The current issue and full text archive of this journal is available at http://www.emeraldinsight.com/0955-6222.htm
Development of a perfusion suit incorporating auxiliary heating and cooling system
Development of a perfusion suit
11
J.E. Ruckman, S.G. Hayes and J.H. Cho Department of Clothing Design and Technology, Manchester Metropolitan University, Manchester, UK
Received February 2001 Accepted August 2001
Keywords Perfusion suit, Cooling garment, Athlete’s performance, Comfort Abstract Based upon numerous assertions that a garment should be developed to maximise athletes’ muscle performance while maintaining freedom of movement, this paper initially discusses the development of a perfusion suit that utilises a flexible single layer cooling system, with a view to the development of a cooling garment that does not employ a conventional tubing system which can restrict movement. The stages of the development have been described in detail, and an appropriate evaluation completed for both the initially developed perfusion suit and the subsequently developed cooling garment (modified perfusion suit). From results obtained from experiments conducted using the cooling garment, which incorporates super absorbent sodium polyacrylate pads as the cooling component, the following conclusions were drawn. First, anterior thigh temperature was reduced by 4– 58C at the end of the cooling period confirming that the developed cooling garment provides effective cooling. Second, although the difference between the skin temperature of the anterior thigh when cooling is applied to that when cooling is not applied decreased during the exercise period, the difference is still significant confirming that cooling of the anterior thigh by wearing the developed cooling garment persists throughout the duration of exercise.
Introduction Temperature regulation is an important issue for athletes as the body functions most effectively only within a limited temperature range. Environmental heat stress can negatively affect sports performance in spite of proper training. Under such stress athletes are unable to maintain thermal balance due to heat acclimation and dehydration. Such incompensable conditions occur especially when the air temperature exceeds 358C and relative humidity becomes higher than 60 per cent R.H. (Nielsen, 1996). To maximise their performance most athletes incorporate some form of warming or cooling of the body into their training, especially if they are anticipating a strenuous start to a race or beginning a high-intensity interval training session. During the years preceding the 1996 Olympic Games in Atlanta many athletes experienced hot and humid weather that is typical to the southern United States (Roos, 1996). It was noticed during the Olympics that some athletes used jackets The work was supported by the Korea Research Foundation Grant (KRF-1999).
International Journal of Clothing Science and Technology, Vol. 14 No. 1, 2002, pp. 11–24. q MCB UP Limited, 0955-6222 DOI 10.1108/09556220210420309
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containing ice packs to pre-cool their bodies in order to delay or reduce the rise in body temperature. It has been suggested that using such jackets in these circumstances improved performance by 2 per cent. It has previously been demonstrated that lowering body temperature provides a wider temperature span before the upper critical body temperature can be reached (Nadal, 1987). Warming or cooling of the body is also necessary to avoid stiff muscles and to prevent muscle injury, as well as to improve performance. Examining the specific effects of temperature change on muscle function is important for athletes as a decrease in muscle temperature of 1 – 28C has been shown to result in a 10– 20 per cent increase in power output, and therefore affects the athletes’ performance in hot environment competition (Sargeant, 1987). Increasing muscle temperature has been shown to produce the opposite effect. Examining the specific effects of temperature change on muscle function is also important in the understanding of an individual’s physiological reaction to thermal stress. Traditional studies (Tikuisis, 1989; Ducharme et al., 1991; Booth et al., 1997; Marino and Booth, 1998; Kay et al., 1999; Marsh and Sleivert, 1999) examining the effects of temperature perturbation on muscle function have commonly employed a water immersion method to induce thermoregulatory responses. Much research has been undertaken to establish the needs of an individual for 1ocalised auxiliary cooling and heating through different devices but mainly using ice packs. Epstein et al. (1986) compared the effects of different cooling devices such as water cooled vest, air cooled hood, ice bag vest and fan cooling under a hot and dry environment (508C, 30 per cent R.H.). They reported that the ice-bag vest had the highest cooling effect on the torso. Thorsson et al. (1985) investigated the effect of 1ocalised cooling on intramuscular blood flow at rest and after running. One leg was cooled for 20 minutes by applying two “instant cold packs” to the quadriceps muscle. Skin temperature was reduced after 4.5 minutes of cooling, both at rest and after running, by 158C and 14.98C respectively. Palmer and Knight (1996) found that different activities resulted in differing responses to ice pack applications. All of the above methods involve ice packs in their original form or incorporated into a vest or a jacket. However, in many cases it was reported that this method is very inconvenient as the ice packs start to melt due to high environmental temperature and the athlete’s body temperature. To avoid this problem, and to address the limitations of the ice jackets, researchers therefore tried to achieve the same effect by utilising a “perfusion suit”. A perfusion suit is a garment incorporating some sort of auxiliary heating and cooling system, normally a liquid heating and cooling tube. A perfusion suit is also referred to as a Liquid Cooling Garment. (Watkins, 1995; Braddock and O’Mahony, 1999). Different perfusion suits with liquid heating and cooling systems have been investigated under various conditions. Nag et al. (1998) examined the efficiency
of auxiliary body cooling under a simulated hot environment using a garment Development of a incorporating a water recirculating three-layered vest of cotton fabric. Xu et al. perfusion suit (1999) investigated the effects of multi-loop controlled liquid cooling garments during exercise under heat stress (358C, 40 per cent R.H.). They used a tripleloop liquid cooling garment by which the torso, arms and legs could be independently cooled. The results showed that a multi-loop control is more 13 effective than a single-loop control. It was also shown that a thorough cooling of the surface over the working muscles, especially leg muscles, provided the greatest thermoregulatory advantage during exercise. According to studies carried out using such perfusion suits, despite a suit incorporating an auxiliary heating and cooling system being effective in optimising the temperature of a part of the body, wearers experience restriction of mobility. This is partly due to the length and coiling of the tubing for the water supply system but mostly due to the fact that perfusion suits used in previous studies were not designed for comfort when a tubing system is incorporated. Since there is a need for the further development of such garments to maximise the athlete’s muscle performance and also allow freedom of movement this paper initially discusses the development of a perfusion suit that utilises a flexible single layer cooling system, and eventually the further development of a perfusion suit that does not employ the conventional type of tubing that can restrict movement but a new high technological material that acts as a cooling element next to the skin. Design and construction of the perfusion suit In situations where body cooling or warming for appropriate muscle function is required without restriction of the wearer’s movement, garment design is crucial. The selection of textile materials is also a key factor in maximising the comfort of the wearer and the performance of a garment, especially in relation to maintaining optimal thermal balance. To construct a perfusion suit incorporating an auxiliary heating and cooling system the concept of the form of the garment was first established. For this study a perfusion suit that provides cooling to the legs, especially quadriceps muscle, was developed using a “chaps” design. The design of the garment is shown in Figure 1. To make up the design into a wearable garment, patrems for the garment were created with a view to ensuring acceptable freedom of movement for the wearer. The pre-shaped and articulated chaps design garment was therefore developed with a pattern consisting of ten pieces; front cut, back cut, front lining, back lining, front knee piece, front lining facing, back lining facing, front crotch facing, back crotch facing, and front and back shanks. These pattems were drawn up to suit a medium sized athlete. To incorporate the cooling system into the perfusion suit it was necessary to use three layers of fabric in the area covering the quadriceps muscle. The detail of features
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demonstrating the concept of the three layers incorporated into the garment is shown in Figure 2. All fabrics, including the three different fabrics required to construct the part of the perfusion suit that is comprised of three layers, were acquired through normal commercial channels. For the three layer encapsulation section: a fabric with low thermal conductivity was identified for the outermost layer to minimise heat flux between the inside and outside of the perfusion suit; a fabric with reasonable flexibility and moisture absorbency was used for the inner layer to hold the cooling system; a fabric with high wicking capability was used for the innermost layer to counteract any perspiration or condensation of vapour on the cooling system that could compromise the garment’s temperature regulation capability. For the rest of the perfusion suit, polyester knitted fabric was chosen for the shanks, and cotton woven fabric was used for the articulated knees. The specifications for the fabrics used in the perfusion suit are shown in Table I. The perfusion suit was constructed according to a pre-shaped and articulated chaps design using Nm75 ballpoint needle and No.120 polyester core-spun thread on a lockstitch sewing machine with a stitch length of 2.5 mm. Preliminary evaluation of the perfusion suit A preliminary experiment was carried out to assess the effectiveness of the perfusion suit by monitoring changes of muscle temperature. The main objectives of this preliminary experiment were to evaluate the suitability of the garment design and to find out if there was any restriction of movement resulting from the use of tubing, despite the garment having been specially designed to incorporate the tubing, and to identify any possible improvements that could be made to the design. For these experiments the perfusion suit was prepared with water recirculating dense latex tubes (Merck 275:1 mm wall Nalgene 180). The tubes were single loop and therefore much more flexible than those used in previous
Figure 1. Design of the perfusion suit
Development of a perfusion suit
15 Figure 2. Schematic diagram of the three layers of fabric incorporated into the perfusion suit
studies. The tubing was attached to the inner layer of the garment covering the quadriceps muscle to allow them to be close to the skin. Cooled water was supplied from a portable temperature-controllable water tank with pumping unit (Grant LTG6G). The extent of body cooling provided was examined by reference to the inlet water temperature and the rate of water flow across the perfusion suit, which was maintained by a thermo-controller with a regulated power supply. One male subject in good physical condition who regularly engages in physically demanding sports, such as rock climbing, undertook the experiment while he was wearing the perfusion suit. Prior to the experiment, thermistors were attached to the subject to measure the skin and muscle temperature. To measure the skin temperature thermistors were securely attached to the anterior of the right thigh with micropore surgical tape. To measure muscle temperature of the quadriceps femoris a small area on the right thigh of the subject was first wiped with disinfectant. The subject was then given a Lindocain (Hydrochloride injection BP 2 per cent W/V 2 ml) for
Material
Weight (g/m2)
Thickness (mm)
Outermost layer
Metallised polyester
71
0.99
Inner layer Innermost layer
100% cotton 100% polyester
140 213
0.36 0.69
Shanks Knees
100% polyester 100% cotton
252 140
1.09 0.36
Section
Special Characteristic Thermal conductivity: 0.023 W.m2 1k2 1 Sateen weave ð37 £ 31=cm2 Þ Hydrophilic finished warp knitted mesh Interlock knitted Sateen weave ð37 £ 31=cm2 Þ
Table I. Specifications of the fabrics used in the perfusion suit
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Figure 3. Skin and muscle temperature whilst wearing a perfusion suit incorporating single layer tubing system
muscle relaxation via a 9.5 cm tube. Finally a sensor was inserted into the quadriceps femoris to a depth of 1.5 cm so that the muscle temperature could be monitored. The subject then put on the garment incorporating a pair of cotton boxer shorts, short sleeve T-shirt, and the perfusion suit. The preliminary experiment was conducted in an environmental chamber ma‘intaining 20 ^ 28C and 35 ^ 5percent R.H. During the experiment, the skin temperature and muscle temperature were recorded at one-minute intervals using a Grant Squirrel meter/logger type SQ8 16U. The experiment was performed for 40 minutes with the subject in a sitting position. The fluctuations of skin temperature on the anterior thigh and muscle temperature during the experiment are shown in Figure 3. The muscle temperature of the quadriceps femoris and skin temperature of the anterior were 30.98C and 22.88C respectively at the beginning of the experiment. Both the muscle temperature and the skin temperature of the anterior thigh tended to decrease with elapsed time. The skin temperature of the anterior thigh dropped rapidly by 58C during the first 10 minutes. After this initial fall, the temperature decreased gradually for the next 22 minutes. The temperature was then stable for 2 minutes and
then increased gradually until the end of the experiment. There was a strong Development of a positive correlation (r ¼ 0:791; p , 0:01) between the skin temperature of the perfusion suit anterior thigh and the muscle temperature. Modification of the perfusion suit The perfusion suit discussed above proved that the use of such a garment can contribute to the control of muscle temperature. It was also found that the effectiveness of such a garment can be estimated by measuring skin temperature changes of the anterior thigh. Although it was shown that a single layer tubing system is flexible enough to be used in a perfusion suit there was still concem about the comfort of the wearer as the system was heavy, to wear and difficult to manage due to the pumping unit that is attached to the tubing system. The perfusion suit was therefore modified to a simpler and lighter design whilst the skeleton of the garment remained the same. This was achieved by replacing the method of Iocalised cooling using cold water through dense latex tubes with re-usable frozen super-absorbent sodium polyacrylate pads. The pads were commercially purchased and used to provide the mechanism through which temperature is regulated. The specification of the superabsorbent material is shown in Table II.
17
Evaluation of the modified perfusion suit (cooling garment) To evaluate the modified perfusion suit two male and four female subjects in excellent physical condition undertook exercise routines whilst wearing the cooling garment both with and without the cooling component incorporated. The average characteristics of the subjects are shown in Table III. Each of the exercise routines consisted of a pre-exercise rest (20 minutes), exercise on an ergometer (Rotronic Hygrometer Monark 814E) rated at 110
Absorbent Covers
Cross-linked sodium polyacrylate Polyethylene Polyester Polyester 315 g/m2 0.64 mm
Dry weight Dry thickness
Number
Age (years)
Weight (kg)
Height (m)
Surface areaa (m2)
6
21.9 ^ 1.76b
61.3 ^ 4.2
1.69 ^ 0.08
1.715 ^ 0.1056
a
DuBois Area (Fanger, 1970). Standard deviation.
b
Table II. Specification of the cooling system used in the modified perfusion suit (cooling garment)
Table III. Mean characteristics of the subjects
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Watts (10 minutes), and a post-exercise rest (20 minutes). A 10-minute cooling period was allowed after the pre-exercise resting period and before the exercise session when wearing the cooling garment incorporating the cooling component. The 10-minute cooling period was considered sufficient as preliminary experiments have shown that the skin temperature of the anterior thigh decreases by 58C during the first 10 minutes of cooling. Prior to the exercise, and towards the end of the 20 minute pre-exercise resting period, thermistors were attached to the subjects to measure skin temperature. All thermistors were securely attached at six different places (high and low parts of the anterior of right and left thighs, upper back and abdomen) with micropore surgical tape. The subjects then changed into the experimental garments comprising a pair of cotton boxer shorts, a round-neck short sleeve T-shirt and the modified perfusion suit. The sodium polyacrylate pads that consisted the cooling component were frozen and then placed in a standard atmosphere for two hours to allow them to reach a temperature of 1 – 38C. The pads were then inserted into the layers of the perfusion suit for the experiments. Experiments were conducted in an environmental chamber maintained at 20 ^ 28C; 65 ^ 5percent R.H. During the exercise, skin temperatures at the six different locations were recorded at one-minute intervals using a Grant Squirrel meter/logger type SQ8 16U. The effectiveness of the modified perfusion suit incorporating the superabsorbent sodium polyacrylate pads as the cooling component is shown in Figure 4. In this figure the skin temperature of the anterior thigh when wearing the modified perfusion suit is compared to the skin temperature when wearing the initially developed perfusion suit incorporating a tubing system. As can be seen from Figure 4, the rate of change of skin temperature of the anterior thigh when wearing the modified perfusion suit is comparable to the rate of change when wearing the initially developed perfusion suit. There is, however, a difference of about 4.58C between the two temperatures throughout the 10minute cooling period, for which there may be to two reasons. First, the latex tubing provides more effective.cooling than super absorbent sodium polyacrylate pads. Second, the two experiments were conducted under different relative humidity (one at 35 per cent R.H., the other at 65 per cent R.H.). Both of these sets of results exhibit a lower rate of temperature decline than that observed in previous research. Thorsson et al. (1985) reported that when ice packs are applied directly to the quadriceps muscle at rest the skin temperature is reduced after 4.5 minutes by 158C. The moderate decrease in skin temperature when wearing the developed perfusion suit is regarded to be due to the design and composition of the garment. Since a rapid fall in skin temperature may cause undesirable health problems (Robergs and Roberts, 1997) this moderate fall in temperature is regarded to be more desirable. At the end of the cooling period, however, the temperature of the anterior thigh when
Development of a perfusion suit
19
Figure 4. Anterior thigh temperature during cooling period
wearing the modified perfusion suit was 26. 138C, which is 4– 58C lower than normal skin temperature of the anterior thigh, confirming that the developed cooling garment provides effective cooling. Since maintaining a low muscle temperature during exercise can maximise the power output of muscles, further analysis was made to ascertain whether the cooled anterior thigh temperature resulting from wearing the modified perfusion suit could be sustained throughout the exercise. For the analysis, skin temperature at both low and high parts of the anterior thigh were plotted (Figure 5). This graph shows that, as discussed previously, there is a great difference between the skin temperature of the anterior thigh when cooling is applied to when cooling is not applied. The difference between these two was reduced during the exercise period, but the difference is still significant (Table IV). The gap decreased further towards the end of the 10 minute exercise period, and although still noticeable continued to decrease throughout the postexercise resting period. Two more interesting phenomena should be noted from Figure 5. First, when cooling is applied the temperature of the low anterior thigh falls dramatically and then increases dramatically as exercise progresses. Second, when cooling is applied the temperature of the low anterior thigh remains lower than that of the high anterior thigh throughout the pre-exercise, exercise and post-exercise period. Another phenomenon observed is that whilst
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Figure 5. Anterior thigh temperature whilst wearing a modified perfusion suit (cooling garment)
the low part of the anterior thigh recorded slightly higher temperature than the high part of the anterior thigh when cooling is not applied during the preexercise resting period, this changes during exercise and the temperature of the low anterior thigh decreases. A decrease in muscle temperature of 1 – 28C results in a 10– 20 per cent increase in power output (Sargeant, 1987). As shown previously in Figure 3, a decrease in muscle temperature has a strong positive correlation with a decrease in skin temperature (58C decrease in skin temperature correlates to a 28C decrease in muscle temperature during the 10-minute cooling period). Therefore, a decrease in skin temperature of the low part of the anterior thigh by 98C during the cooling period and 48C during the exercise period by wearing the modified perfusion suit will also prove to contribute to a decrease in muscle temperature by at least 1 – 28C. The changes in average skin temperature throughout the experiments are shown in Figure 6. This is based on the calculation of average skin temperature taken from six different parts of the subjects’ bodies. According to Figure 6 the average skin temperature immediately prior to exercise (30.668C when cooling was not applied and 26.138C when cooling was applied) changes dramatically as soon as the subjects begin exercise. The skin temperature of subjects when
Time (min.) E1 E2 E3 E4 E5 E6 E7 E8 E9 E10
No cooling ð8C ^ s:d:Þ
Cooling ð8C ^ s:d:Þ
t value
29.33 ^ 1.18 29.07 ^ 1.26 28.92 ^ 1.30 28.83 ^ 1.36 28.74 ^ 1.40 28.76 ^ 1.51 28.77 ^ 1.56 28.78 ^ 1.65 28.81 ^ 1.70 28.88 ^ 1.74
24.98 ^ 4.26 25.50 ^ 3.65 25.84 ^ 3.33 26.12 ^ 3.07 26.37 ^ 2.93 26.59 ^ 2.82 26.81 ^ 2.75 27.02 ^ 2.70 27.23 ^ 2.68 27.44 ^ 2.70
42.013 32.049 26.765 19.632 15.665 11.081 8.275 5.786 4.730 4.515
t-test sig. , 0.05 *** *** *** *** *** *** ** ** * *
Development of a perfusion suit
21 Table IV. Skin temperatures of anterior thigh during exercise and the result of t-test
cooling is not applied decreases whilst the skin temperature of subjects when cooling is applied increases steadily. The initial decrease in skin temperature when cooling is not applied may be due to convection created around the ergometer whilst the subject is conducting exercise. This phenomenon has been previously observed (Timmis and Ball, 1997; Ruckman et al., 1999). The discrepancy between the skin temperature when cooling was not applied and the skin temperature when cooling was applied is clearly shown in Figure 6 (2.808C difference during the first minute of exercise and 0.878C difference
Figure 6. Average skin temperature whilst wearing a modified perfusion suit (cooling garment)
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Table V. Average skin temperatures and the result of t-test
Time (min).
No cooling ð8C ^ s:d:Þ
Cooling ð8C ^ s:d:Þ
Mean skin temperatures during the exercise E1 30.41 ^ 1.97 E2 30.23 ^ 2.11 E3 30.14 ^ 2.20 E4 30.06 ^ 2.25 E5 29.98 ^ 2.28 E6 29.98 ^ 2.31 E7 30.00 ^ 2.34 E8 29.93 ^ 2.47 E9 30.02 ^ 2.39 E10 30.06 ^ 2.37 Skin temperatures during the post-exercise rest PE1 30.27 ^ 2.16 PE2 30.45 ^ 2.05 PE3 30.57 ^ 2.01 PE4 30.72 ^ 1.96 PE5 30.84 ^ 1.93 PE6 30.95 ^ 1.89 PE7 31.02 ^ 1.89 PE8 31.05 ^ 1.86 PE9 31.07 ^ 1.86 PE10 31.10 ^ 1.83 PE11 31.08 ^ 1.81 PE12 31.10 ^ 1.79 PE13 31.08 ^ 1.77 PE14 31.07 ^ 1.77 PE15 31.10 ^ 1.76 PE16 31.14 ^ 1.76 PE17 31.16 ^ 1.76 PE18 31.16 ^ 1.76 PE19 31.06 ^ 1.72 PE20 31.00 ^ 1.78
t value
t-test sig. , 0.05
27.60 ^ 5.18 27.94 ^ 4.67 28.15 ^ 4.36 28.33 ^ 4.13 28.48 ^ 3.95 28.63 ^ 3.81 28.77 ^ 3.70 28.72 ^ 3.61 29.05 ^ 3.52 29.19 ^ 3.45
23.806 19.607 16.450 14.023 12.747 12.226 10.987 8.028 8.843 8.271
*** *** *** *** *** ** ** ** ** **
29.58 ^ 3.26 29.82 ^ 3.09 30.04 ^ 2.93 30.17 ^ 2.90 30.32 ^ 2.84 30.42 ^ 2.75 30.47 ^ 2.67 30.56 ^ 2.61 30.65 ^ 2.58 30.67 ^ 2.50 30.71 ^ 2.45 30.72 ^ 2.38 30.79 ^ 2.32 30.82 ^ 2.31 30.84 ^ 2.28 30.84 ^ 2.25 30.85 ^ 2.25 30.89 ^ 2.25 30.93 ^ 2.26 30.92 ^ 2.23
12.960 12.952 11.622 12.680 11.706 10.883 8.711 8.913 8.184 7.557 6.915 4.885 4.479 4.194
*** *** *** *** *** ** ** ** ** ** * * * *
during the last minute of exercise). The difference between the average skin temperature when cooling is not applied and average skin temperature when cooling is applied proved to be significant, as shown in Table V, especially during the initial period of exercise. A significant difference ðp , 0:05Þ between the cooled and non-cooled skin temperature was also noted throughout the 10 minutes exercise period and for 14 minutes during the post-exercise resting period. Conclusions Based upon numerous assertions that a garment should be developed to maximise athletes’ muscle performance that also allows freedom of movement,
this paper initially discussed the development of a perfusion suit that utilises a Development of a flexible single layer cooling system, with a view to the further development of a perfusion suit cooling garment that does not employ a conventional tubing system, which restricts movement, but instead a new high technology material that acts as the cooling element next to the skin. The stages of the development have been described in detail, and an 23 appropriate evaluation completed for both the initially developed perfusion suit and the modified perfusion suit (the cooling garment). From the experiments conducted using the finalised cooling garment, which incorporates super absorbent sodium polyacrylate pads as the cooling component, the following two results were observed which confirm the effectiveness of the cooling garment. First, the anterior thigh temperature was reduced by 4 – 58C at the end of the cooling period when wearing the cooling garment. Second, although the difference between the skin temperature of the anterior thigh when cooling is applied to that when cooling is not applied decreased during the exercise period, the difference is still significant confirming that the cooled anterior thigh temperature resulting from wearing the developed cooling garment is sustained throughout the exercise. References Braddock, S.E. and O’Mahony, M. (1999), Techno Textiles, Thames and Hudson, London. Booth, J., Marino, F. and Ward, J.J. (1997), “Improved running performance in hot humid conditions following whole body precooling”, Medicine and Science in Sports and Exercise, Vol. 29 No. 7, pp. 943-49. Ducharme, M.B., VanHelder, W.R. and Radomski, M.W. (1991), “Cyclic intramuscular temperature fluctuations in the human forearm during cold-water immersion”, European Journal of Applied Physiology and Occupational Physiology, Vol. 63 No. 3/4, pp. 188-93. Epstein, Y. and Shapiro, S. Brill (1986), “Comparison between different auxiliary cooling devises in a severe hot/dry climate”, Ergonomics, Vol. 29 No. 1, pp. 28-41. Fanger, P.O. (1970), Thermal Comfort: Analysis and Applications in Environmental Engineering, McGraw-Hill, New York. Kay, D., Taaffe, D.R. and Marino, F.E. (1999), “Whole-body pre-cooling and heat storage during self-paced cycling performance in warm humid conditions”, Journal of Sports Sciences, Vol. 17 No. 12, pp. 937-44. Marino, F. and Booth, J. (1998), “Whole body cooling by immersion in water at moderate temperatures”, Journal of Science and Medicine in Sport, Vol. 1 No. 2, pp. 73-81. Marsh, D. and Sleivert, G. (1999), “Effect of precooling on high intensity cycling performance”, British Journal of Sports Medicine, Vol. 33 No. 6, pp. 393-97. Nadal, E.R. (1987), “Prolonged exercise and high and low ambient temperature”, Canadian Journal of Sport Science, Vol. 12, pp. 140S-42S. Neilson, B. (1996), “Olympics in Atlanta: a fight against physics”, Medicine and Science in Sports and Exercise, Vol. 28 No. 6, pp. 665-68. Nag, P.K., Pradhan, C.K., Nag, A., Ashtekar, S.P. and Desai, H. (1998), “Efficacy of a water-cooled garment for auxiliary body cooling in heat”, Ergonomics, Vol. 41 No. 2, pp. 179-87.
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Palmer, J.E. and Knight, K.L. (1996), “Ankle and thigh skin surface temperature changes with repeated ice pack application”, Journal of Athletic Training, Vol. 31 No. 4, pp. 319-23. Roos, R. (1996), “Heat stress in Atlanta: preparing for the Olympic worst”, Physiology Sports medicine, Vol. 24 No. 6, pp. 89-99. Robergs, R.A. and Roberts, S.O. (1997), Exercise Physiology, Mosby, St. Louis. Ruckman, J.E., Murray, R. and Choi, H.S. (1999), “Engineering of clothing systems for improved thermophysiological comfort: the effect of openings”, International Journal of Clothing Science and Technology, Vol. 11 No. 1, pp. 37-52. Sargeant, A.J. (1987), “Effect of muscle temperature on leg extension force and short-term power output in humans”, European Journal of Applied Physiology, Vol. 56, pp. 693-98. Tikuisis, P. (1989), “Prediction of thermoregulatory response for clothed immersion in cold water”, European Journal of Applied Physiology and Occupational Physiology, Vol. 59 No. 5, pp. 334-41. Timmis, J.A. and Ball, D. (1997), “The influence of temperature on the Torque-Velocity relationship of human knee extensors and flexors”, Journal of Sports Science, Vol. 64, pp. 64. Thorsson, O., Lilja, B., Ahlgren, L., Hemdal, B. and Westlin, N. (1985), “The effect of local cold application on intramuscular blood flow at rest and after running”, Medicine and Science in Sports and Exercise, Vol. 17 No. 6, pp. 710-13. Watkins, S.M. (1995), Clothing: The Portable Environment, Iowa State University Press, Iowa. Xu, X.J., Hexamer, M. and Wemer, J. (1999), “Multi-loop control of liquid cooling garment systems”, Ergonomics, Vol. 42 No. 2, pp. 282-98.
The current issue and full text archive of this journal is available at http://www.emeraldinsight.com/0955-6222.htm
Estimating thermal resistance of dry infant bedding — Part 1: a theoretical mathematical model C.A. Wilson and R.M. Laing
Estimating thermal resistance 25 Received December 2000 Accepted July 2001
Clothing and Textile Sciences, at the University of Otago, Dunedin, New Zealand Keywords Insulation, Thermal testing Abstract The purpose of this work was to develop a model for estimating “dry” and “wet” thermal resistance of bedding during use. The model takes into account proportions of the body covered by different bedding arrangements, and the effects of an infants sleep position and method of tucking on thickness, thermal resistance and heat loss. Predictions of thermal resistance using various published formulae are compared with those from this study.
1. Introduction The possible link between thermal stress and SIDS (Sudden Infant Death Syndrome) has lead to evaluations into how the thermal resistance and other characteristics of bedding assemblies affects heat loss from the infant body (Bolton et al., 1996; Fleming et al., 1990; Nelson et al., 1989; Ponsonby et al., 1992; Wailoo et al., 1989; Wigfield et al., 1993). Differences in sleep position, method of tucking, and bedding products used have also been identified between case and control infants (L’Hoir et al., 1998; Williams et al., 1996). For example, infants sleeping in the prone position and those using a duvet have both been linked to increased risk of SIDS, while firm tucking and use of a “drycot” (a “waterproof” under-bedding layer) have been linked to reduced risk (L’Hoir et al., 1998; Williams et al., 1996; Wilson et al., 1994). Precisely how these variables affect the risk of SIDS is unclear. However, the method of tucking, infant sleep position and the type of bedding affect the thermal resistance of bedding during use (Wilson et al., 2000; Wilson et al., 1999b). In an attempt to assess the risk of SIDS, different methods for estimating the thermal resistance of clothing and bedding have been developed. Most are based on the assumption that the covering(s) is of uniform thickness and thus The assistance of J. Anderson, B. Niven, Burston Nuttal, and Alliance Textiles Ltd. is gratefully acknowledged. When measuring thickness of the bedding C. Wilson was supported partially by the New Zealand Cot Death Association, a division of the National Child Health Research Foundation.
International Journal of Clothing Science and Technology, Vol. 14 No. 1, 2002, pp. 25–40. q MCB UP Limited, 0955-6222 DOI 10.1108/09556220210420318
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resistance over the surface of both the bed and body is uniform. Thermal resistance of bedding which consists of multiple-layers is also commonly assumed to be estimated by adding either the thickness (Bolton et al., 1996; Tuohy and Tuohy, 1990) or “dry” thermal resistance (Ponsonby et al., 1992; Wigfield et al., 1993; Williams et al., 1996) of individual layers measured flat. Estimates are commonly based on measurements of “dry” thermal resistance determined byClulow (1978; 1986). The effect of variables such as tucking and sleep position on the arrangement of bedding and air space(s) formed during use has only recently been taken into account (Wilson et al., 1999a; Wilson et al., 2000; Wilson et al., 1999b). During use, bedding adopts one of two possible configurations depending on it’s position in relation to the human body: i) that immediately over the body where minimal air spaces are formed between bedding layers, and ii) adjacent to the body where larger air spaces are formed between textile layers (Wilson et al., 1998). This three-dimensional arrangement of bedding affects the surface area in each configuration (i.e. minimal air spaces were estimated to be approximately 18 per cent of the bedding cross section in the lateral and 36 per cent in the prone and supine positions) (Wilson et al., 1999b). Thus, the proportion of the bedding surface area with minimal air spacing is relatively small. A further complicating factor is that the thickness of bedding immediately over the body can be less than the thickness of bedding adjacent to the body (by approximately 1000 per cent) (Wilson et al., 1998). Using the thickness or thermal resistance of the multiple-layer bedding with minimal air spaces between layers to estimate the overall insulation appears likely to result in incorrect estimates. Consequently, the relationship between thermal resistance of bedding during use and SIDS may not have been adequately assessed. The aim of this work was to develop a theoretical mathematical model for estimating thermal resistance of upper-bedding which accommodates the effects of sleep position and method of tucking on the bedding configuration and thus thermal resistance 2. Theoretical analysis This model of the three-dimensional bedding system is based on the following assumptions: .
the thickness of clothing does not contribute to overall thermal resistance of the bedding;
.
the infant chest is circular and the body (excluding the head) is thus represented by the frustum of a cone;
.
the mattress and bedding beyond the feet and edges of the bed form super-insulating barriers (i.e. no heat is lost from the body along the x-axis (Figure 1a and b) and thus the effective surface area available for heat transfer does not extend to the edges of the bed;
Estimating thermal resistance 27
Figure 1. Orientation of the bedding during use and variables used to estimate the width of the bedding surface (x axis) and surface area of each section of the “body” (y axis)
IJCST 14,1
.
heat loss through bedding immediately adjacent to the body ranges from negligible along the x-axis to almost the equivalent to that which occurs immediately over the body at the z-axis;
.
the proportion of the bedding with minimal air spacing between layers remains constant along the length of the “body” (y-axis) because as the diameter of the “body” decreases along its length the width of the bedding across the x-axis decreases; and
28
as the diameter of the “body” decreases along its length the combined thickness of the bedding plus air layers adjacent to the “body” decreases. A number of surface areas and proportions of the body are required to estimate heat loss i.e. the nude surface area of the body; the effective surface area of the bedding; the proportions of the bedding surface area across the width of the bed (x-axis) with minimal air spaces and with air layers between; and the proportions of the bedding surface area along the y-axis. The nude surface area, represented by the frustum of a cone excluding the frustum ends (Figure 2a), is: D þ df A ¼ pl ð1Þ 2 .
where A is the surface area of the frustum (m2), i.e. the nude surface, D the maximum diameter of the frustum (m) i.e. the chest, df the minimum diameter of the frustum (m) i.e. foot length, and l the length of the frustum (m) i.e. recumbent length (crown to foot). Coverings change the surface from which heat is lost and also increase the surface area available for transfer. The distance between two sites along the bedding cross-section (x-axis) was used to determine the length of the surface. The two boundary sites were selected by examining bedding cross-sections and considering the extent of contact between the upper sheet and mattress layer (Wilson et al., 1999b). Total distance along the surface of the bedding (Figure 1b) and distances over and adjacent to the body were estimated for two sleep positions (lateral and prone/supine) and three tucking arrangements (loosely, or firmly tucked or swaddled) according to: bT ¼
8 X
bi
ð2Þ
i¼1
where bT is the total distance of the external bedding surface along the x axis (mm), bi the surface distance of segment i between ffi sites (mm), e.g. 100 to pffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi 150 mm (Figure 1b) bi ¼ ð ðziþ1 2 zi Þ2 þ ðxiþ1 2 xi Þ2 Þ, i the segment across the width of the mattress surface (50 mm), i ¼ 1 – 10, xi the measurement site i ¼ 1 – 8 (mm), i.e. sites 100 to 500 mm, zi the thickness of bedding at site xi (mm) and
Estimating thermal resistance 29
Figure 2. Variable used to calculate the surface area of a frustum of a cone and surface area of the bedding trapezoid
bover ¼
X
biover
and badj ¼
i
X biadj
ð3Þ
i
where biover is the surface distance of bedding over the body along the x axis (mm) and biadj the surface of bedding adjacent to the body along the x axis (mm) Proportions of the bedding over and adjacent to the body were thus: xover ¼
bover bT
and
xadj ¼
badj bT
ð4Þ
IJCST 14,1
30
where xover is the proportion of the external enclosing surface (i.e. the bedding) over the body with minimal air spaces between, xadj the proportion of the external enclosing surface adjacent to the body with air spaces between. Distance along the surface of the bedding across the foot (Figure 2b) was estimated by comparing the total distance across the surface of the bedding (determined using the bedding cross-section across the shoulders of the “body”) with the perimeter of the nude “body” for each sleep and tucking position according to: Dper: ¼ pD
ð5Þ
and distance aT estimated: aT ¼ bT
d fper Dper
ð6Þ
The effective surface area of the bedding was therefore: Aeff ¼ 0:5lðaT þ bT Þð1 2 0:21c
ð7Þ
where: Dper is the perimeter of the “body” (m), aT the distance across the bedding surface (x axis) at the “bottom” of the “body”, dfper the perimeter of the “body” (m), Aeff the total surface area of the bedding available to transfer heat to the ambient environment (m2), c the constant, where c ¼ 1 if the head is uncovered and c ¼ 0 if the head is covered. The surface area, thermal resistance of bedding and thickness of the various air spaces formed adjacent to the “body” decrease down the length of the bed (yaxis) as diameter of the “body” decreases. Thus the length of the body was divided into three sections. The thermal resistance of section 1 was estimated using the material and air arrangement formed at site 450 mm (x-axis) and section 3 the arrangement at site 100 mm (x-axis) (i.e. based on foot length). Section 2 was estimated as intermediate between sections 1 and 3. The proportions of nude surface area of the “body” resulting from each section (Figure 1c) were estimated as: X D i þ d f i Asi ¼ pl si ð8Þ 2 i where Asi is the surface area of each section of the frustum, i ¼ 1 – 3 (m2), Di the upper diameter of section i, where i ¼ 1 – 3 (m), dfi the lower diameter of section i, where i ¼ 1 – 3 (m), lsi the length of each section of the frustum, where i ¼ 1 – 3. The length of each section was determined using a 1:2:1 ratio and surface area calculated (Equation 1). The decrease in diameter between the top (D ) and
bottom (df) of the “body” was determined by estimating the Di and dfi for each section as follows (Figure 1c): DD ¼ ðD 2 d f Þ=4
ð9Þ
Estimating thermal resistance
and
31
d f1 ¼ D 2 DD ¼ D2 d f2 ¼ D2 2 ðDD·2Þ ¼ D3 d f3 ¼ D3 2 ðDDÞ ¼ df and the proportion of the surface area accounted for by each section was calculated according to: ysi ¼
Asi A
where :
A ¼ ðAs1 þ As2 þ As3 Þ
ð10Þ
where df1 – 3 is the lower diameter of each section of the “body” (m), D1 – 3 the upper diameter of each section of the “body” (m), DD the change in diameter between the upper and lower ends of the total “body”, and ysi the a constant representing the proportion of surface area attributable to each section of the “body”, where i ¼ 1 – 3. “Dry” and “wet” thermal resistance of bedding during use are thus estimated according to: Rct ¼ ðRctover xover Þ þ {½ðRctadjs1 ys1 Þ þ ðRctadjs2 ys2 Þ þ ðRctadjs3 ys3 Þxadj }
ð11:1Þ
Ret ¼ ðRetover xover Þ þ {½ðRetadjs1 ys1 Þ þ ðRetadjs2 ys2 Þ þ ðRetadjs3 ys3 Þxadj }
ð11:2Þ
where Rctadj Si is the Rctadj ¼ 0:278 þ 0:0127d 2 0:0024d a1 þ 0:00226d a2 þ 0:0143da3 2 0:0041d a4 2 ð0:344if duvet is present Þ, Retadj Si the Retadj ¼ 0:024 þ 0:0010d 2 0:0002da1 þ 0:0018d a2 2 ð0:0346if duvet is present Þ, Rctover the Rctover i.e. minimal air spaces between layers (m2 K/W) where Rctover ¼ 0:051 þ 0:023d 2 ð0:469if duvet is present Þ (Wilson et al., 1999a), Retover the Retover where there are minimal air spaces between layers (m2 kPa/W) according to Wilson et al., (2000): Retover ðif no duvet is presentÞ ¼ 0:001 þ 0:002d or Retover ðif a duvet is presentÞ ¼ 20:007 þ 0:001dd = thickness of the air spaces dai determined according to Wilson et al. (1999b))and total thermal resistance of the material and adherent air layer as: RctT ¼ Rct þ Rctad RetT ¼ Ret þ Retad
ð12Þ
IJCST 14,1
32
where: RctT is the total “dry” thermal’ resistance of the bedding assembly during use including resistance of the adherent air layer (m2 K/W), RetT the total “wet” thermal resistance of the bedding assembly during use including resistance of the adherent air layer (m2 kPa/W), Rctad the “dry” thermal resistance of the adhering air layer (m2 K/W) (Wilson et al., 1999a): Rctad ¼ 0:197 2 000343d ad , Retad the “wet” thermal resistance of the adhering air layer (m2 kPa/W) (Wilson et al., 2000): Retad ¼ 0:0111d 0:2411 Total heat loss ad was thus: QT ¼ Qd þ Qe
ð13Þ
where: Qd ¼
ðTsk 2 Ta Þ RctT
ð13:1Þ
ðP sk 2 P a Þ RetT
ð13:2Þ
and Qe ¼
where: QT is the total heat transfer (W/m2), Qd the “dry” heat transfer (W/m2), Qe the “wet” heat transfer (W/m2).
3. Application of the model The application of this model depends on access to information about the infants sleep position and tucking arrangement (which affect size and distribution of air spaces), and bedding combinations used. Ambient environment and skin temperature, and vapour pressure data are also required. Data on infants is required. However, given the age of the infants in question (,1 year) and the ethical issues surrounding measurement of some sleep and wrapping combinations (e.g. the prone sleep position and/or duvet use have been identified as increasing risk of SIDS) alternatives to direct validation of the model such as using manikins, were investigated. However, while infant manikins exist, they are either partial infant manikins (e.g. a hip manikin for assessing diapers), too large for the purposes of this study (a toddler), or simplified premature manikins designed for testing incubators (Bolin et al., 1989; Nanameki et al., 1998; Sarman et al., 1992). Thus, validation of the model requires laboratory data from a balance study (similar to that described by Wigfield et al., (1993)) prior to application of the model to SIDS case and control data. Validation will form Part two of this series. To compare resistance and heat loss values calculated using this model with those published by other researchers (Bolton et al., 1996; Ponsonby et al., 1992;
Wailoo et al., 1989; Wigfield et al., 1993), the model was applied using “set” values identified from the published literature. Four bedding combinations (a sheet (S), a sheet and nine blankets ðS þ 9 AÞ; and two of the most common bedding combinations (a sheet and two air-cell blankets (SAA) and a sheet, two air-cell and duvet (SAAD)) commonly used to cover New Zealand infants were used (Wilson et al., 1994). Items were: .
cotton sheet, plain weave, napped, 18:8 £ 16:6 yarns=10 mm; thickness X ¼ 2:5; s:d: ¼ 0:3 mm;
.
wool blanket, cellular or air-cell, weft faced, 5:2 £ 4:0 yarns=10 mm; thickness X ¼ 6:0; s:d: ¼ 0:3 mm;
panel quilt or duvet, bulked polyester filling; polyester/cotton, woven plain weave cover, 32:8 £ 19:5 yarns=10 mm; thickness X ¼ 34:8; s:d: ¼ 1:8 mm: The thickness of bedding/air combinations formed during use was measured as previously described in Wilson et al., (1999b) and relevant thermal resistances determined (Wilson et al., 1999a; Wilson et al., 2000). Dimensions of the “infant” were assumed to be: weight 5100 g; chest circumference 0.37 m; recumbent length 0.56 m; foot length 0.08 m; surface area of the nude “body” 0.14 m2 (Snyder et al., 1977). An example of surface areas for the lateral sleep position and other variables are given in Table I a – c. When estimating total heat loss (Equation 13), temperature, relative humidity and vapour pressure at the skin surface were assumed to be Tsk ¼ 35:0 8C; 20 per cent R. H. and thus P sk ¼ 3:17 kPa with no sensible water loss, and ambient conditions Ta ¼ 16:7 8C; 50 per cent R.H. P sk ¼ 0:38 kPa (Bolton et al., 1996; Tuohy and Tuohy, 1990). .
4. Results The estimated thermal resistance of dry bedding immediately over the manikin with minimal air spaces between layers ranged from 0.29 to 1:19 m2 K=W for “dry”, and from 0.02 to 0:10 m2 kPa=W for “wet” thermal resistance (Figure 3a). “Dry” and “wet” thermal resistance of all bedding combinations differed significantly (F 3;356 ¼ 23877:55; p # 0:001; F 3;356 ¼ 60440:02, p # 0:001 respectively). Thermal resistance (“dry” and “wet”) of the sheet and nine blankets layers was 310 per cent and 400 per cent (respectively) greater than that of the sheet only. Thermal resistance of bedding adjacent to the manikin with air spaces between layers ranged from 0.18 to 1.02 m2 K/W for “dry” and from 0.02 to 0.08 m2k Pa/W for “wet” thermal resistance. Depending on the tucking and sleep position resistance varied from that with minimal air spaces between by 217 to 29 per cent and 250 to 30 per cent respectively (Figure 3a). However, when comparing mean values only, thermal resistances did not vary significantly irrespective of whether thickness of bedding adjacent to or
Estimating thermal resistance 33
IJCST 14,1
34
Table I. Surface areas, variables and thickness used to estimate integrated thermal resistance of the bedding system (m, unless otherwise stated)
Tucking and manikin position
bT
aT
bover
badj
a Surface areas Lateral Loose 0.66 0.46 0.05 0.61 Swaddled 0.58 0.41 0.11 0.48 Firm 0.67 0.46 0.05 0.62 Prone Loose 0.46 0.32 0.15 0.31 Swaddled 0.49 0.34 0.22 0.28 Firm 0.46 0.32 0.21 0.26 Supine Loose 0.44 0.31 0.15 0.29 Swaddled 0.46 0.32 0.20 0.25 Firm 0.44 0.30 0.15 0.29 b Section variables Section 1 Section 2 Section 3 Total Diameter (m) D 0.12 0.11 0.09 0.12 df 0.11 0.09 0.08 0.08 Length (m) 0.11 0.22 0.11 0.44 Surface area (m2) 0.04 0.07 0.03 0.14 0.29 0.50 0.21 1.00 Proportions (ysi) c Thickness of X¯ S.D. bedding (mm) S 1.65 0.23 SAA 10.25 0.25 SAAD 60.80 2.43 S þ 9A 41.00 0.46
Aeff Aeff cov (m2) unc (m2)
xover
xadj
0.08 0.19 0.08
0.92 0.81 0.92
0.24 0.21 0.24
0.19 0.17 0.19
0.33 0.44 0.45
0.67 0.56 0.55
0.17 0.18 0.17
0.13 0.14 0.13
0.35 0.45 0.35
0.65 0.55 0.65
0.16 0.17 0.16
0.13 0.13 0.13
cov. = head covered. unc. = head uncovered.
immediately over the body, was used to estimate resistance (t 3 ¼ 1:61; NS; t3 ¼ 0:52; NS). The “dry” and “wet” thermal resistances of the bedding estimated using the integrated model are shown in Figure 3b. “Dry” thermal resistance of the entire bedding assembly ranged from 0.27 to 1.12 m2 K/W and “wet” thermal resistance from 0.02 to 0.10 m2 kPa/W. Differences between the thermal resistance of bedding adjacent to the body and that determined using the integrated model ranged from 250 per cent to 7 per cent for “dry” and 225 per cent to 33 for “wet” thermal resistance. Differences reflected the effect of tucking and sleep position, and thus the non uniform thickness of bedding, on thermal resistance of the bedding during use. Type of bedding combination ðF3;359 ¼ 18845:67; p # 0:001; F3;359 ¼ 23523:98; p # 0:001Þ; sleep position ðF2;359 ¼ 2211:96; p # 0:001; F2;359 ¼ 1944:24; p # 0:001Þ; and tucking arrangements ðF2;359 ¼ 471:69; p # 0:001;
Estimating thermal resistance 35
Figure 3. Estimated “dry” and “wet” thermal resistance of bedding
IJCST 14,1
36
F3;359 ¼ 4344:22; p # 0:001Þ significantly affected both “dry” and “wet” thermal resistance respectively when estimated using the integrated model. Sleep position and tucking arrangement also had a combined effect on thermal resistance of the bedding ðF6;359 ¼ 97:03; p # 0:001; F6;359 ¼ 120:54; p # 0:001Þ: The estimated total heat losses ranged from 223.65 to 44.40 W/m2 immediately over the manikin through bedding with minimal air spaces and from 257.86 to 46.46 W/m2 adjacent to the manikin through bedding with air spaces (Table II). As expected the most heat was lost through the sheet and least through the sheet and nine air-cell blankets. Estimating total heat loss through bedding using thickness of bedding immediately over the manikin only, masked differences which resulted from the various manikin positions and methods of tucking.
¯ X
Table II. Estimated total heat loss through bedding ðT a ¼ 16:7 8C; P a ¼ 0:380; T sk ¼ 35:0 8C; P sk ¼ 3:172 kPaÞ (W/m2, n ¼ 10)
S S.D.
¯ X
SAA S.D.
a Over the body with minimal air spaces between 223.65 5.27 118.32 1.62 b Adjacent to the body with air spaces between Overall mean 155.72 58.77 146.41 31.09 Lateral Loose 131.74 1.12 101.66 0.70 Swaddled 257.86 3.79 168.79 1.78 Firm 257.86 3.79 168.79 1.78 Prone Loose 115.75 0.76 93.68 0.55 Swaddled 156.41 1.39 118.68 0.88 Firm 156.41 1.39 118.68 0.88 Supine Loose 82.93 0.40 70.68 0.32 Swaddled 121.27 0.84 97.13 0.59 Firm 121.27 0.84 97.13 0.59 C Integrated – both over and adjacent to the body Lateral Loose 111.00 0.79 88.63 0.54 Swaddled 198.22 2.61 134.45 1.32 Firm 195.62 2.32 137.06 1.26 Prone Loose 131.21 1.28 97.27 0.77 Swaddled 170.62 2.33 114.44 1.15 Firm 171.33 2.36 114.50 1.16 Supine Loose 99.27 0.74 78.25 0.51 Swaddled 144.64 1.68 102.04 0.92 Firm 136.18 1.39 99.61 0.82
¯ X
SAAD S.D.
¯ X
S+9A S.D.
57.37
2.32
44.40
0.42
75.11
14.36
61.36
9.10
68.03 97.36 97.36
2.90 5.92 5.92
57.39 75.74 75.74
0.39 0.66 0.66
66.56 78.70 78.70
2.73 3.86 3.86
55.73 63.73 63.73
0.36 0.47 0.47
53.37 67.96 67.96
1.76 2.85 2.85
46.46 56.85 56.85
0.25 0.37 0.37
61.20 79.05 83.42
2.38 4.06 4.42
51.99 62.53 66.21
0.34 0.53 0.54
61.76 66.17 65.98
2.54 2.97 2.96
50.55 52.64 52.46
0.39 0.45 0.45
52.73 61.37 62.23
1.86 2.57 2.59
44.57 49.71 50.82
0.30 0.41 0.40
The use of mean total heat loss to represent the losses through bedding adjacent to the body does not adequately describe the possible range of losses through the various bedding configurations (Table IIb). Estimates of thermal resistance using the integrated model illustrated differences in resistance over the surface of the bed during use. Thus calculating heat loss using estimates of thermal resistance derived using the integrated model are likely to be better representative of what actually occurs. The predicted thermal resistances using various formulae (Bolton et al., 1996; Ponsonby et al., 1992; Wailoo et al., 1989; Wigfield et al., 1993) were compared with those from this study and are shown in Figure 4.
Estimating thermal resistance 37
5. Discussion Conclusions formed about total heat loss for a specific level of insulation and ambient conditions are likely to be erroneous if based i) only on thermal resistance of bedding with minimal air spaces between layers and ii) if the
Figure 4. Comparison of estimates of “dry” and “wet” thermal resistance and total heat loss derived using the integrated model of Wilson and Laing with that of selected authors
IJCST 14,1
38
effect of “wet” thermal resistance is not accounted for. With the exception of Bolton (1996), the effect of “wet” thermal resistance of materials on their insulation has been largely ignored (Fleming et al., 1990; Nelson et al., 1989; Ponsonby et al., 1992; Wailoo et al., 1989; Wigfield et al., 1993). When thermal resistance estimated using the integrated model is compared with that of other researchers it can be seen that use of mean values subsumes the effect of differences in the distribution and size of air spaces among sleep positions and tucking arrangements. Use of mean values based on thickness of bedding with minimal air spaces between layers fails to address the question of how methods of use affect insulation and thus risk of SIDS. The integrated model proposed in this paper enables the effect of body position and tucking on the thickness of bedding adjacent to the body to be accommodated by utilising thickness of bedding with air spaces between layers in the calculation of thermal resistance. Thus the model accommodates differences in thickness of bedding both across and down the length of the bed; proportions of the bedding with minimal air spaces and air spaces between layers; and how these variables affect both “dry” and “wet” thermal resistance of the bedding. Researchers have suggested that SIDS cases have greater thermal insulation for a given room temperature than matched controls (Ponsonby et al., 1992); that SIDS is associated with too little insulation (i.e. when not firmly tucked in infants become more vulnerable to SIDS) (Williams et al., 1996); and that thermal resistance of bedding over a prone infant is greater than that over other sleep positions. However, methods used to estimate thermal insulation do not appear to have been sufficiently sensitive to differences in resistance to enable the relationship between SIDS and insulation levels to be satisfactorily assessed. For example, thermal resistance of loosely tucked bedding estimated using the integrated model were consistently higher (up to 27 per cent) than firmly tucked bedding or bedding over swaddled infants, irrespective of sleep position. In addition, the prone sleep position (implicated in risk) generally resulted in thermal resistance values intermediate between that for the same bedding over a body in the lateral and supine positions. Re-examination of the relationship between insulation level and risk of SIDS is required. Part II of this series will address validation and re-examine the relationship between insulation and risk of SIDS.
6. Conclusions The total thermal resistance of the upper bedding used for infant care is not adequately described by either the thickness of bedding immediately over or that adjacent to the body. The model proposed accommodates differences in thickness and thermal resistance across the bedding and allows their effect on total heat loss to be taken into account. Total heat transfer through bedding
combinations should thus be determined using the integrated method rather than estimated from thickness of bedding immediately over the infant. Use of the integrated model to estimate thermal resistance of bedding used to insulate infants in their homes, assumes that the air layer arrangements documented and ambient and skin temperature and vapour pressure are representative of those that occur during actual use. Estimating “dry” and “wet” thermal resistance of (Equation 12) and heat loss through (Equation 13) infant bedding used in the home requires measurement of: .
infant weight, chest circumference and both recumbent and foot length;
.
classification of bedding composition as either duvet(s) or other;
.
total thickness of the bedding assembly when arranged flat and with minimal air spaces between; and
.
ambient and infant skin temperature and relative humidity under conditions of use. For example during a nominated sleep or as soon after death as possible.
References Booth, J.E. (1975), Textile mathematics, The Textile Institute, Manchester. Bolin, D., Holme´r, I., Sarman, I. and Tunell, R. (1989), “The use of an infant thermal manikin for assessment of different neonatal heating equipments for premature newborn babiesrldquo;, in Kin, Y., Spelman, F.A. (Eds), Images of the twenty-first century: Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society. 11th Annual International Conference, Institute of Electrical and Electronic Engineers, Seattle, Washington pp. 252-3. Bolton, D.P.G., Nelson, E.A.S., Taylor, B.J. and Weatherall, I.L. (1996), “A theoretical model of thermal balance. Implications for the sudden infant death syndrome”, Journal of Applied Physiology, Vol. 80 No. 6, pp. 2234-42. Clulow, E.E. (1978), “Thermal insulation properties of fabrics”, Textiles, Vol. 7 No. 2, pp. 47-52. Clulow, E.E. (1986) Extended list of thermal insulation values for infants bedding and clothingvalues used to calculate thermal insulation. Figures in Tables I to V in analysis of survey of 100 infants. Report No. N7012. Shirley Institute. Fleming, P.J., Gilbert, R., Azaz, Y., Berry, P.J., Rudd, P.T., Stewart, A. and Hall, E. (1990), “Interaction between bedding and sleeping position in the sudden infant death syndrome: a population based case control study”, British Medical Journal, Vol. 301 No. 6743, pp. 85-9. L’Hoir, M.P., Engelberts, A.C., van Wall, G.T.J., McClelland, S., Westers, P., Dandachli, T., Mellenbergh, G.J., Wolters, W.H.G. and Huber, J. (1998), “Risk and preventive factors for cot death in The Netherlands, a low-incidence country”, European Journal of Pediatrics, Vol. 157 No. 8, pp. 681-8. Nanameki, T., Kang, I. and Tamura, T. (1998), “Evaluation of heat and moisture transport properties of infants’ clothing”, in, Second International Conference on HumanEnvironment System, Human-Environment System, Yokohama, Japan pp. 186-9. Nelson, E.A.S., Taylor, B.J. and Weatherall, I.L. (1989), “Sleeping position and infant bedding may predispose to hyperthermia and the sudden infant death syndrome”, Lancet, Vol. i No. 8631, pp. 199-202.
Estimating thermal resistance 39
IJCST 14,1
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Ponsonby, A.L., Dwyer, T., Gibbons, L.E., Cochrane, J.A., Jones, M.E. and McCall, M.J. (1992), “Thermal environment and sudden infant death syndrome: Case control study”, British Medical Journal, Vol. 304 No. 6822, pp. 277-82. Sarman, I., Bolin, D., Holme´r, I. and Tunell, R. (1992), “Assessment of thermal conditions in neonatal care: use of a manikin of premature baby size”, American Journal of Perinatology, Vol. 9 No. 4, pp. 237-44. Snyder, R. G., Schneider, L. W., Owings, C. L., Reynolds, H. M., Golomb, D. H. and Schork, M. A. (1977) Anthropometry of Infants, Children and Youths to Age 18 for Product Safety Design. Report No. SP-450. Highway Safety Research Institute, The University of Michigan. Tuohy, P.G. and Tuohy, R.J. (1990), “The overnight thermal environment of infants”, New Zealand Medical Journal, Vol. 103 No. 883, pp. 36-8. Wailoo, M.P., Petersen, S.A., Whittaker, H. and Goodenough, P. (1989), “The thermal environment in which 3-4 month old infants sleep at home”, Archives of Disease in Childhood, Vol. 64 No. 4, pp. 600-4. Wigfield, R.E., Fleming, P.J., Azaz, Y.E.Z., Howell, T., Jacobs, D.E., Nadin, P.S., McCabe, R. and Stewart, A.J. (1993), “How much wrapping do babies need at night? Laboratory and community studies agree”, Archives of Disease in Childhood, Vol. 69 No. 2, pp. 181-6. Williams, S., Taylor, B.J. and Mitchell, E.A. and other members of the national Cot Death study group (1996), “Sudden infant death syndrome: Insulation from bedding and clothing and its effect modifiers”, International Journal of Epidemiology, Vol. 25 No. 2, pp. 366-75. Wilson, C.A., Taylor, B.J., Laing, R.M. and Williams, S. and the New Zealand Cot Death study group (1994), “Clothing and bedding and its relevance to sudden infant death syndrome: further results of the New Zealand Cot Death Study”, Journal of Paediatrics and Child Health, Vol. 30 No. 6, pp. 506-12. Wilson, C.A., Niven, B.E. and Laing, R.M. (1998), “Estimating thermal resistance of multiplelayer materials”, in, Second International Conference on Human-Environment System, Human-Environment System, Yokohama, Japan pp. 160-3. Wilson, C.A., Laing, R.M. and Niven, B.E. (1999a), “Estimating thermal resistance of multiplelayer bedding materials — re-examining the problem”, Journal of the HumanEnvironment System, Vol. 2 No. 1, pp. 69-85. Wilson, C.A., Niven, B.E. and Laing, R.M. (1999b), “Estimating thermal resistance of bedding from thickness of materials”, International Journal of Clothing Science and Technology, Vol. 11 No. 5, pp. 262-76. Wilson, C.A., Laing, R.M. and Niven, B.E. (2000), “Multiple-layer bedding materials and the effect of air spaces on “wet” thermal resistance of dry materials”, Journal of the HumanEnvironment System, Vol. 4 No. 1, pp. 23-32.
The current issue and full text archive of this journal is available at http://www.emeraldinsight.com/0955-6222.htm
Graphical analysis of bra size calculation procedures M.C.M. Wright
Bra size calculation procedures 41
Institute of Sound and Vibration Research, University of Southampton, UK
Received October 2000 Accepted August 2001
Keywords Garments, Measurement Abstract A widely used procedure for calculating bra size from body measurements is analysed graphically. It is shown that arbitrarily small variations in the body measurements can cause a difference of up to three cup sizes in the calculated bra size. Some implications are discussed and improved procedures suggested.
1. The calculation procedure The rise of internet shopping has brought an increasing need for consumers to measure themselves rather than consulting experienced fitters. An internet search has revealed that variations on the following procedure for calculating bra sizes is quoted on many retail sites and elsewhere: (1) Measure around the ribcage just under the bust in inches. (2) If the result is even add four, otherwise add five, this is the band size. (3) Measure around the bust at its fullest point. (4) Subtract the result of (2) from the result of (3). (5) Convert this number to a letter, this is the cup size. There is an implicit assumption that the results of steps (1) and (3) must be integers. It will be assumed in what follows that this is the result of a rounding to the nearest integer, so that the range from 0.5 to 1.499. . .rounds to 1, etc. Variations are found in the letter system used in step (5), but these are immaterial to the discussion that follows. For definiteness the system shown in Table I, which is common in the UK, will be used. Mathematically the procedure defines a mapping from two continuous variables x and y, the actual ribcage and bust sizes, to two discrete variables X and Y, the resulting band and cup size. This mapping can be written X ¼ 2bðbx þ 1=2c þ 5Þ=2c;
ð1Þ
Y ¼ by þ 1=2c 2 2bðbx þ 1=2c þ 5Þ=2c;
ð2Þ
where bxc is the greatest integer less than or equal to x. Hence or otherwise, the domain in (x, y ) space occupied by each (X, Y ) pair can be found. This is plotted in Figure 1 with Y expressed as a letter.
International Journal of Clothing Science and Technology, Vol. 14 No. 1, 2002, pp. 41–45. q MCB UP Limited, 0955-6222 DOI 10.1108/09556220210420327
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As can be seen from Figure 1, each size (i.e. each distinct (X, Y ) pair) occupies a rectangular domain in (x, y ) space, 2 inches wide and 1 inch tall. The domains corresponding to a particular cup size, however, are not adjacent, whereas there exist pairs of domains whose cup sizes differ by two which are horizontally adjacent. By the same token there exist pairs of domains whose cup sizes differ by three which are diagonally touching. This means that arbitrarily small errors in x and y could, if they caused the measurement to cross the relevant diagonal boundary between domains, change a predicted size from an A-cup to a D-cup, for example. The cup size is suppposed to describe the difference between the bust and ribcage sizes. The points on a line inclined at 458 in (x, y ) space have a constant difference between x and y. It is impossible, however, to draw such a line on Figure 1 so that it passes through the domains corresponding to any one cup size for more than half of its length, if the line is continued far enough. Coincidentally it is often claimed that 50% of women in the UK wear the wrong size of bra, although a literature search has failed to reveal any published research to support this statistic. Note also that although cup sizes go up in one inch steps the difference between the smallest and largest values of x 2 y to be assigned to the same cup size is three inches.
2. An alternative procedure The cause of these anomalies can be seen in Equation (2). The ribcage size x is rounded twice, once (implicitly) when measured and then again when made even. The cup size Y, therefore, is the difference between two rounded quantities, which allows the rounding errors to accumulate. That error is plus or minus half an inch for the first term, and plus or minus one inch for the second, leading to an accumulated error of plus or minus one and a half inches, corresponding to the three inch range in x 2 y values. The situation can be improved by modifying the procedure as follows: (1) Measure around the ribcage just under the bust in inches. (2) Add five to the result. (3) Measure around the bust at its fullest point rounding up to the next integer. (4) Subtract the result of (2) from the result of (3). (5) Convert this number to a letter, this is the cup size. (6) If the result of (2) is odd subtract one, this is the band size. Table I. Key to cup size letters
21 AA
0 A
1 B
2 C
3 D
4 DD
5 E
Bra size calculation procedures 43
Figure 1. Domain map for first procedure
This corresponds to the following mapping: X ¼ 2bðbx þ 1=2c þ 5Þ=2c;
ð3Þ
Y ¼ by þ 1c 2 bx þ 1=2c 2 5;
ð4Þ
which is plotted in Figure 2. Now all the domains corresponding to a particular cup size are at least diagonally touching and it is possible to draw a continuous 458 line which passes only through the domains corresponding to a single cup size. The cup size is still the difference of two rounded quantities, but the error in the second is reduced because now it is only rounded once. The range of y 2 x values to be assigned to the same cup size therefore becomes two inches, as can be verified from Figure 2. For completeness it may be worth pointing out that it is possible to completely remove all error accumulation by arranging for the difference operation to occur before any rounding. This could be achieved if, for example, a disposable paper tape were used to make the measurements, on which marks were made to indicate its position when placed around the ribcage and bust. The calculation procedure would then be: (1) Measure the distance from the beginning of the tape to the first mark. (2) If it is even add four, if it is odd add five, this is the band size. (3) Measure the difference between the marks rounding up to the next integer. (4) Subtract five and convert to a letter.
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Figure 2. Domain map for second procedure
The corresponding mapping is X ¼ 2bðbx þ 1=2c þ 5Þ=2c;
ð5Þ
Y ¼ by 2 x þ 1c 2 5;
ð6Þ
which is plotted in Figure 3. This reduces the range of y 2 x over a cup size to one inch, albeit at the expense of a more involved procedure.
3. Discussion In practice consumers will usually find their preferred size by trial and error, although this may not always be the case if the 50 per cent statistic mentioned above does have any basis in fact. The success of any procedure can only be judged by the likelihood of its predicting the same size as would be chosen by trial and error, and no such procedure can be as successful as an experienced fitter. But with the rise of internet shopping the reliance on such procedures seems likely to grow. The graphical analysis carried out above suggests that the second procedure should have a greater likelihood of success than the first. Naturally the manufacturers’ implementation of sizes will be a factor in the success of any procedure, but generally this will only affect the location and scaling of the patterns in Figures 1 and 2, not the relative positions of the domains therein. In particular it is hard to conceive of a rational manufacturing strategy for which the first procedure is more suitable than the second.
36E
38D
36DD
38C
34E
36D
38B
34DD
36C
38A
34D
36B
38AA
34C
36A
34B
36AA
40B
Bra size calculation procedures
40A 40AA
The implications of this analysis go beyond manufacturer/retailer/consumer relationships. Before reconstructive or cosmetic breast surgery the postoperative bra size is predicted, and the mappings discussed above can be signigicant (Kanhai, 1999). Furthermore, medical statistics relating, for instance, incidence of cancer to breast size may be based on census data which asks for cup size. The procedure used to calculate that cup size could then have implications for the interpretation of such statistics. References Kanhai, R.C.J. and Hage, J.J. (1999), “Bra cup size depends on band size”, Plastic and Reconstructive Surgery, Vol. 104 No. 1, pp. 300.
45
Figure 3. Domain map for third procedure
The current issue and full text archive of this journal is available at http://www.emeraldinsight.com/0955-6222.htm
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Dimensions of apparel manufacturing strategy and production management Shu-Hwa Lin
Received August 2000 Accepted October 2001
North Carolina Central University, Durham, NC, USA
Mary Ann Moore Florida State University, FL, USA
Doris H. Kincade Virginia Tech, Blacksburg, VA, USA
Carol Avery Florida State University, Tallahassee, FL, USA Keywords Manufacturing strategy, Sewing, Production management, Apparel Abstract The purpose of this study was to explore the dimensions of apparel manufacturing strategy (i.e. cost, quality, flexibility, delivery time) and their relationship to style and sewing systems. U.S. apparel producers are seeking strategies that will make their production competitive to production in low wage countries. Two style types were defined: new styles and standardized styles. Results indicated that the production of new styles of apparel is related to the manufacturing dimensions of quality and delivery. The standardized style is related to the dimension of cost. Significant associations were also found between the multiple-sewing systems used by plants and dimensions of manufacturing strategy (cost, delivery, and flexibility).
International Journal of Clothing Science and Technology, Vol. 14 No. 1, 2002, pp. 46–60. q MCB UP Limited, 0955-6222 DOI 10.1108/09556220210420336
1. Introduction The U.S. apparel industry is facing the greatest challenge in its history because of the rapidly changing business environment with respect to global competition, market performance, and changing technology (Abernathy et al., 1995; Mize, 1992). The high amount of labor involved in apparel production (30 per cent – 50 per cent of the final garment cost) has caused apparel producers to seek locations with lower wage employees for reduced production costs. Apparel producers in less-developed countries have labor-cost advantages compared to industrialized countries. The result of this wage differential has contributed to an import deficit for the United States so that low-wage countries are producing more than half of the products sold in the U.S. market (Abernathy et al., 1995). This global competition is expected to become even stronger in the future. U.S. apparel producers must seek strategies and use dimensions of the manufacturing process that will create a competitive product when low wage employees are not present.
Ongoing changes in the international business environment have dictated changes in management’s approach to U.S. apparel manufacturing. In addition, new technologies are available to facilitate major changes in U.S. production systems (AAMA, 1996; Mize, 1992). Communication technologies, automatic air or light controlled sewing machines, and laser and ultrasonic cutting can provide quick response capability and improved apparel quality in U.S. apparel industry. Use of the optimal manufacturing strategy in conjunction with a sophisticated production management approach is required to continue to produce products effectively and efficiently with these new technologies (Mize, 1992; Taplin, 1994). While apparel producers are trying to reduce inefficiencies within the production process, they must be concerned with market performance. Successful market performance will depend on the availability of style variations to meet consumers’ needs. In 1992, Kotabe suggested that U.S. firms should have better manufacturing strategies and should develop manufacturing capabilities to meet market needs. An examination of style characteristics in relation to dimensions of manufacturing strategies is important in developing the production management approach needed for U.S. apparel producers. Production systems must be in place to support these manufacturing strategies. As international competitiveness continues to be a critical issue, the U.S. apparel industry has acknowledged the need for improved production systems (Gereffi, 1994). Empirical research, which examines a broad population of apparel producers to describe the relationship between dimensions of apparel manufacturing strategy and any production activities, is needed (Kotabe, 1992). In addition, no formulas or models appear to exit to explain these relationships for apparel production. This study was designed to explore the dimensions of apparel manufacturing strategy and to determine the relationships of these dimensions (i.e. quality, cost, delivery, flexibility) to (a) style types (i.e. new and standardized) and (b) selection of apparel production systems for the manufacturing process. 2. Background 2.1. Dimensions of manufacturing strategy Planning effective manufacturing strategies is an important means of coping with a changing business environment and may help companies achieve a competitive advantage or maintain an already prominent position. Manufacturing strategy is defined as an effective plan of manufacturing capability for the achievement of business goals in a future environment (Schroeder and Lahr, 1990). Researchers have identified the most frequently used dimensions of manufacturing strategy as cost, quality, delivery, and flexibility (Ettlie and Penner-Hahn, 1994; Kim and Lee, 1993). Although companies differ on their use of these four dimensions, apparel producers
Dimensions of apparel manufacturing 47
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generally accept basic definitions of the four dimensions. Cost is defined as price efficiency or the production price of a product. Quality is defined as conformance of product performance to consumer preferences in the decision to adopt products. Delivery involves speed and service to the customer. Flexibility refers to the variety and quantity of products available to meet consumer requirements. As Swamidass and Newell (1987) indicated, manufacturing strategies are designed to make effective use of a company’s manufacturing strengths as a competitive weapon for business success. Several studies in different other fields have been conducted comparing manufacturing strategies to manufacturing environmental performance or outcomes of the strategy (Ettlie and Penner-Hahn, 1994; Shroeder and Lahr, 1990); however, to date, only two studies exploring manufacturing strategies in relation to characteristics of the production environment have been found. The theoretical model by Kim and Lee (1993) suggested that manufacturing strategies are related to the choice of production systems. For the field of apparel, only Ko and Kincade (1998) have surveyed U.S. apparel manufacturers, and they found that adoption of the Quick Response strategy, for manufacturing, is related to production line features. No literature suggests an explicit analytical framework for understanding the relationship between apparel manufacturing strategies and the of the production environment.
2.2. Style types Style types (i.e. new and standardized) for the apparel product include more variety of styles than any other manufacturing industry within the product line (Kotabe, 1992; Scahill, 1985). This large number of styles creates variation within the product line. Within certain product and price categories, the variation in style is important to please the consumer. Style variations help to maintain a competitive advantage (MacDuffie et al., 1996; Kotabe, 1992). Although important to the consumer, Meredith (1981) reported that variations in style play a key role in the overall variation within the production environment. Sources of style types increase the cost of manufacturing because they require reengineering of the apparel production line (Meredith, 1981). This reengineering causes downtime, re-calibration of equipment, and reconfiguration of assembly processes. When a new style is to be initiated in the plant, the production line manager needs to reengineer the production line, and sewing operators have to be retrained to master new sewing sequence. The reengineering required to meet these production demands have associated costs of manufacturing. Costs will generally increase as the number of style types and changes increases. Variations generated through these style characteristics have the potential to influence the priority placed on the dimensions of manufacturing strategy.
For style type, scholars have suggested a two-stage, product cycle model consisting of new products and standardized products. The first stage consists of new products, and the second stage contains standardized products (Fischey and Harrington, 1996; Kotabe, 1992; Scahill, 1985). Scahill (1985) stated that a new style is likely to involve a series of unstandardized production sequences. Scahill also stated that a new style cannot be produced economically. Either, it cannot be mass-produced or operators may not be familiar with the new assembly skills required. Although many authors have predicted the link between style variations and dimensions of manufacturing strategy such as cost and flexibility, limited empirical evidence exists to support these predictions. 2.3. Production systems One of the major features within the plant or production environment is the production system. A production system includes the machinery and processes used to change raw materials to a finished product. The system is also described by the flow of goods through the system and the relationship of workers to the equipment and to each other. Apparel production systems are also called sewing systems and have gained a great deal of attention in the last ten years (Solinger, 1988). Many variations of old and new systems have been introduced and have been defined and/or named with an array of terms (e.g., stand up, agile, lights out, team, modular). Various classifications of sewing systems were designed to meet the variety of production needs (Solinger, 1988). In this study, a sewing system is defined as a specific type of apparel production system that involves the flow of materials, the types of equipment, the layout of sewing machines and equipment, and the activities of the operators (Cooklin, 1991; Solinger, 1988). This study used the production system analysis method based on the work of Kim and Lee (1993). Although hundreds of sewing systems are used in the world today, the basic conventional and teamwork production systems were selected for this study. For this study, the conventional sewing system included the Bundle system and the Progressive Bundle system, and the teamwork system was represented by the Modular System. In the Bundle System (BS) of production, the bundle is the unit of work. The system was named from the bundles of components that are moved sequentially from workstation to central deposit and back and back to the next workstation (Solinger, 1988). Each workstation is a highly specialized operation. BS is considered a broken sequence or layout in that each sewing machine operator performs one operation or a series of operations on a bundle of garments (Solinger, 1988). Sewing operators participate in extremely standardized training for greatest productivity and large volume. The Bundle System is the oldest mass apparel production system and is still widely used in many apparel plants today (Lin et al., 1995).
Dimensions of apparel manufacturing 49
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The Progressive Bundle System (PBS) is a variation of BS. In PBS, the workstations are grouped to create skill centers. The bundles flow from workstation to workstation within a skill center (Cooklin, 1991; Solinger, 1988). Machines for similar operations are placed together, and subsequent operations are placed sequentially for direct flow between skill centers. Machines and operations continue to be highly specialized and interchangeable. A Modular Production System (MPS) is a teamwork sewing system. The unit of work is a garment. Components for one garment are fed into the workflow in single ply so that bundles of components are not moved. Dissimilar machines are clustered into a skill center or team area, for a self contained workflow. Components are passed by hand or KanBan as needed for the next operation. Cross-trained sewing teams perform short production runs and are involved in line decision making. Operators are interchangeable among tasks within the team to the extent practical, and incentive compensation is based upon the team’s output of first quality products (The [TC]2 Manufacturing Team, 1995). BS and PBS are generally associated with issues of cost. Solinger (1988) noted that BS could be the most productive system because of the use of sectionalized and highly specialized workstations. Operators can be very productive because of the repetitive nature of their operators. These systems are also viewed as appropriate for standard products with few changes. MPS is associated with quality and flexibility dimensions of a manufacturing strategy ([TC]2, 1995). With hand-to-hand workflow and in-line decision-making, operations are encouraged to evaluate and improve quality as the garment is constructed. Team work and cross train operations are features of MPS that indicate the flexibility of the system for easily handling style variation. Although these relationships are generally accepted as true, limited empirical evidence exists to support these assumptions. 2.4. An apparel manufacturing model To explore the production environment, an Apparel Manufacturing Model (AMM) was proposed by this researcher based on the theory of Kim and Lee (1993), and several conceptual frameworks (Ettlie and Penner-Hahn, 1994; Kotable, 1992; Schroeder and Lahr, 1990; Taplin 1994). The AMM (Figure 1) examines the complex relationship between dimension of apparel manufacturing strategy and other aspects of the production environment. This model depicts a manufacturing flow chart, with the association of manufacturing strategy dimensions to style types and the selection of an optimal production system. The manufacturing process includes the production system. Improving business performance is the major reason for implementing a manufacturing strategy. According to trade sources and scholars, dimensions of apparel manufacturing strategy can be used to enhance the production environment and to determine the most economic and feasible manufacturing strategy. For
Dimensions of apparel manufacturing 51
Figure 1. Apparel Manufacturing Model
an optimal production, environment a producer should consider selection of an appropriate production system (Taplin, 1994) Manufacturing strategy can be influenced by product market demands such as style types and style changes (AAMA, 1986). Style types and/or style changes help to maintain a competitive advantage (MacDuffie et al., 1996; Kotabe, 1992). A test of these assumptions and the proposal relationships among dimensions of manufacturing strategy, style variations and production systems is the purpose of this research. 2.5. Hypotheses To meet the purpose of this study, the following hypotheses were proposed: (1) There will be no significant differences between companies in respect to the dimensions of apparel manufacturing strategy (i.e. quality, cost, delivery, flexibility).
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(2) There will be no significant relationship between dimensions of apparel manufacturing strategy (i.e. quality, cost, delivery, flexibility) and style types (i.e. new and standardized). (3) There will be no significant relationship between the dimensions of apparel manufacturing strategy (i.e. quality, cost, delivery, flexibility) and the apparel sewing system (i.e. BS, PBS, MPS). (4) There will be no significant relationship between the style types (i.e. new and standardized) and apparel sewing systems (i.e. BS, PBS, MPS). 3. Research design This ex post facto study was designed to explore the dimensions of apparel manufacturing strategy (i.e. quality, cost, delivery, flexibility) and to examine the relationship of style types (i.e. new and standardized) to these dimensions in the U.S. apparel industry. The relationship of manufacturing strategy dimension and style types with the selection of sewing systems were also examined. The apparel industry has a large and versatile population that is spread over the entire U.S. A mail survey was utilized as the most effective method of reaching different geographic locations. A disproportionate stratified random sample of 450 apparel producers was selected from three groups of apparel producers (i.e. publicly owned apparel manufacturers, privately owned apparel manufacturers, contractor/manufacturers). The sample included 150 randomly selected apparel producers from each of the three groups. Those publicly-owned apparel manufacturers were listed in the WWD Supplier’s Guide 1994 (American Business Information, 1996). Privately owned apparel manufacturers and contractor/manufacturers were listed in the Directory of AAMA (AAMA, 1995) and Sourcing Guide (American Apparel Contractors Association [AACA], 1995-1996) respectively. This multiple source sampling was used to achieve a broad selection of apparel producers and to reduce bias from any single list. 3.1. Instrument The questionnaire for this study was developed by the researcher based on previous research and trade definitions. The self-administrated questionnaire contained three sections: (a) dimensions of manufacturing strategy, (b) production information including style types and sewing systems, and (c) demographic information. Both close-ended and open-ended questions were included in the questionnaire. A four-item measure was used to assess apparelmanufacturing strategies (quality, cost, delivery, and flexibility). Dimensions of apparel manufacturing strategy were measured on a 7 point Likert-type scale (1 = Least Important, 7 = Most important). Style type was measured with openended questions that ask for the number of each style type per season. This
question was developed from Mize (1992) description of products. The sewing system variable was a series of open-ended questions that ask for the number of production lines operated by each producer for each type of system: bundle, progressive bundle, modular and other (Solinger, 1988). An additional multiplechoice question was asked to determine if the producer had multiple or single lines in the plant. Demographic characteristics and product types were openended questions. Dillman (1978) Total Design Method for implementing mail surveys was used as a guide for mailing the questionnaires and for follow-up. The questionnaire was pilot tested with industry personnel, not in the final sample, for validity and reliability. The questionnaires were mailed to production managers/engineers or operation managers of the companies selected in the sample. 3.2. Data analysis Data were coded and entered on the Statistical Analysis System (SAS) program. Frequencies were used to examine the dimensions of apparel manufacturing strategy (Hypothesis 1). Hypotheses 2 and 3 were examined by utilizing discriminant analysis and ordinary least squares regression. Proc Candisc was used for the discriminant analysis. Hypothesis 4 was examined by regression analysis (Aldrich and Nelson, 1986). Logistic regression was chosen over discriminant analysis because of better prediction and classification (Cabrera, 1994). 4. Findings and discussion One hundred and ten usable responses were received for an adjusted response rate of 30.3 per cent. The adjusted sample size was 363 and was adjusted because of non-deliverables, incorrect business, closed business, and unwilling to participate. The number of personnel employed at respondent locations varied from ten to 10,000. Approximately three-fourths of the sample (73.8 per cent) reported employing more than 100 people. Products produced by the responding plants included men’s, women’s, and children’s apparel, and others types of garments such as disposable clothing and industrial uniforms. The most frequently manufactured product was T-shirts/sportswear (28 per cent), followed by men’s shirts (10 per cent), and women’s blouses (9 per cent) (Table I). The number of new styles ranged from 0 to 450 per season; the mean was 32.68 new styles per season. Almost three-fourth of the plants (72.8 per cent) produced four or more new styles per season, and almost half (46.8 per cent) of the plants reported more than six new styles per season. The number of standardized styles produced in a season ranged from 1 to 350; the mean number of standardized styles was 38.47. Fifty-four percent of the respondents reported that they produced more than six standardized styles per season.
Dimensions of apparel manufacturing 53
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Characteristics A. Number of Employees 1 – 19 20 – 99 100 – 499 500 & over B. Type of Product T-shirt & sportswear Men’s shirts Women’s blouses Men’s suits Men’s slacks Jean’s Swimwear, bodywear Uniforms Career wear Children’s wear Women’s underwear Waterproof outerwear Others
Table I. Characteristics of the responding companies
C. Sewing Systems BS1 PBS2 MPS3 OTHERS Total
Frequency
Percentage (%)
2 24 51 22 99
2.0 24.2 51.5 22.3 100.00
28 10 9 7 7 7 6 5 4 3 3 2 9 100
28 10 9 7 7 7 6 5 4 3 3 2 9 100.0
50 50 30 10 140
35.7 35.7 21.5 7.1 100.0
Note: All respondents did not answer every question. 1BS = Bundle System, 2PBS = Progressive Bundle System, 3MPS = Modular Production System. Twenty plans used more than one type of sewing system.
To identify the types of systems used by producers, the producer was identified as having a system if they had at least one line in the plant using that system. Both of the conventional sewing systems, BS and PBS (35.7 per cent each, n ¼ 50), were the types of sewing systems most frequently reported by the respondents. Modular Production Systems were reported by 21.5 per cent ðn ¼ 30Þ of the companies. About 7 per cent of the plants ðn ¼ 10Þ reporting sewing systems other than the types listed in the questionnaire. Twenty plants reported using more than one type of sewing system. 4.1. Hypothesis 1 – dimensions of manufacturing strategy This study is explored the patterns or combinations for dimensions of apparel manufacturing strategy (i.e. quality, cost, delivery, flexibility. The standard deviations for the four dimensions of apparel manufacturing strategy were less
than 1.5, and the means were very similar, ranging from 5.4 (flexibility) to 6.4 (quality). Almost all of the respondents tended to give high scores to all four of the dimensions of manufacturing strategy, meaning all dimensions are of general importance to the apparel producers (see Table II).
Dimensions of apparel manufacturing
4.2. Hypothesis 2 – relationship of strategy dimensions to style types Canonical discriminant analysis was used to determine whether the dimensions of manufacturing strategy are related to style types. Style types was defined as new and standardized in this study. Style types have been noted as important on selected manufacturing strategies for the auto industry (MacDuffie et al., 1996). Two statistically significant associations were found between the production of new styles and the individual manufacturing strategy dimension of quality ðF ¼ 2:28; p ¼ 0:006Þ and delivery ðF ¼ 2:05; p ¼ 0:01Þ: One discriminant function, including all four dimensions of manufacturing strategy, was tested and was significant with Roy’s Greatest Root (Roy’s Greatest Root = 1.42, F½26; 53 ¼ 2:89; p ¼ 0:0005) showed a significant relationship between new styles and the four manufacturing strategy dimensions considered at one time. One significant association between the production of standardized styles and individual manufacturing strategy dimensions of cost was found in the discriminant analysis ðF ¼ 1:88; p ¼ 0:02Þ: Roy’s Greatest Root did indicate a significant overall relationship (Roy’s Greatest Root = 0.93, F½26; 60 ¼ 2:14; p ¼ 0:008) between these variables. Standardized styles derived manufacturing strategies on the cost. This indicates that cost as major factor on apparel manufacturing strategy (see Table III). The null hypothesis of no significant relationship between the apparel manufacturing strategies and style types was rejected. Production of new styles has strong associations with quality and delivery, while the production of standardized styles appear to be associated with cost strategy. This indicates that manufacturers that are producing new styles and have frequent style changes must constantly adjust their strategies to respond to market needs. As Schroeder and Lahr (1990) observed, manufacturing strategy needs to respond to business needs. Also, manufacturing strategy should change constantly according to altered business environments and situations (Schroeder and Lahr, 1990).
55
Variables
Mean
Standard Deviation
Quality Cost Delivery Flexibility
6.40 5.94 6.02 5.37
1.10 1.34 1.19 1.37
Table II. Manufacturing strategies
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F Value
p Value
New Style Quality Cost Delivery Flexibility
2.2751 1.2852 2.0510 0.7847
0.0056** 0.2163 0.0135* 0.7461
Standardized Style Quality Cost Delivery Flexibility
1.3311 1.8760 0.8616 1.0300
0.1801 0.0231* 0.6544 0.4473
Note. * significant at .05,
**
significant at .01.
4.3. Hypothesis 3 – relationship between strategy dimensions and sewing system Canonical Discriminant analysis was also used to examine the suggested relationships between manufacturing strategies and sewing systems. The variable of sewing systems was used as the number of lines within a system that was reported by the respondents. In addition the variable of multiple types of systems or a single system type within the plant was examined. Significant associations between the use of the Bundle System (BS) and three individual manufacturing strategy dimensions were found in the discriminant analysis; cost ðF ¼ 6:19; p ¼ 0:01Þ; delivery ðF ¼ 11:43; p ¼ 0:001Þ; and flexibility ðF ¼ 13:02; p ¼ 0:0005Þ: The same three significant associations were found between the Progressive Bundle System (PBS) and the individual manufacturing strategies of cost ðF ¼ 9:04; p ¼ 0:003Þ; delivery ðF ¼ 11:27; p ¼ 0:0011Þ; and flexibility ðF ¼ 11:17; p ¼ 0:001Þ: The high proportion of the respondents who used the BS and the PBS, were good data for statistical analysis. No significant relationships were found between the use of Modular, the Toyota Sewn management, or other systems reported by the respondents and any of the manufacturing strategies. Perhaps, there are limited respondents make hard to fit model (see Table IV). Significant associations were also found between the multiple-sewing systems used by plants and individual manufacturing strategies (cost: F ¼ 3:09; p ¼ 0:01; delivery: F ¼ 3:59; p ¼ 0:005; and flexibility, F ¼ 3:07; p ¼ 0:01) Roy’s Greatest Root tests also confirm that the overall relationship between the multiple-sewing systems used by plants and the manufacturing strategies are significantly related. The null hypothesis that there will be no significant relationship between the selection of apparel sewing systems and manufacturing strategies was rejected. The model of Kim and Lee (1993) suggested that different manufacturing strategies must be linked to different production systems in order to succeed. Results of this study support this
Variable
F Value
p Value
2.14 6.19 11.43 13.02
0.15 0.01* 0.001*** 0.0005****
2.28 9.04 11.27 11.17
0.13 0.003** 0.001** 0.001**
A. Type of sewing system Bundle system Quality Cost Delivery Flexibility Progressive bundle system Quality Cost Delivery Flexibility Modular System Quality Cost Delivery Flexibility Others Systems Quality Cost Delivery Flexibility B.Sewing System Used by Plant Quality Cost Delivery Flexibility Note. * significant at .05,
**
significant at .005,
0.008 0.29 0.09 1.01
0.93 0.59 0.77 0.31
0.20 0.41 0.73 0.43
0.82 0.66 0.48 0.65
1.46 3.09 3.59 0.07
0.21 0.01* 0.005** 0.01*
***
significant at .001,
****
significant at .0005
assertion and indicate that manufacturing strategies influence the selection of sewing systems.
4.4. Hypothesis 4 – relationship of style type to sewing systems Relating of style type to sewing system by plants was tested in a regression analysis. Levels in the style type analysis were the numbers of new styles and standardized styles. Sewing systems were used as the number of production lines that were in one plant for each system type. A significant linear relationship was found between the production of new styles and the sewing systems used by plants (See Table V). The R2 of this model is 22.82 ðF ¼ 5:46; p , 0:02Þ and 76.0 per cent of variations is addressed in the model. Introduction of new styles into the production environment may suggest that producers have at least three sewing system options available to produce garments.
Dimensions of apparel manufacturing 57
Table IV. Discriminant analysis for manufacturing strategy dimensions and sewing systems
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5. Discussion The apparel industry is a highly competitive industry that generally operates with very little research and few reports. Survey-based empirical research is especially important, as the field lacks an accumulation of reliable findings across a variety of plants. At one time, the industry was seen as a sunset industry; however, everybody needs clothing every day. The challenge for U.S. producers is how to design an optimal apparel manufacturing strategy (Ettlie and Penner-Hahn, 1994). Firms always should be evaluating dimensions of manufacturing strategy to meet new competitiveness. One aspect of this argument is that a firm’s major manufacturing decisions should enhance its competitive advantage. Significant associations between new styles and the individual dimension of quality and delivery were found in the discriminant analysis. The relationship between standardized styles and the individual dimension of cost was also significant. The frequency of style changes was significantly associated with the strategies of quality and delivery with mass production. Producers can possibly lower costs, reduce production time, and improve quality, while frequent style changes require quick delivery and quality that is acceptable to customers. The results of this study are consistent with the literature (Cooklin, 1991; Solinger, 1988; Taplin, 1994). Additionally, results indicate that the sewing systems used by plants were significantly related to the plant’s individual dimensions of a manufacturing strategy and further illustrate the importance of an optimal manufacturing strategy. The most effective way for plant managers or production engineers to select the most appropriate sewing system(s) is to consider the dimension of a manufacturing strategy to achieve the firm’s business goals. Style variations related to the sewing system used by plants were included in the analysis. Regression analysis showed that new styles and the selection of sewing systems by plants are linearly related. The other aspects of style variations were not significantly related to the sewing system. Literature indicated that new styles require the reengineering of the whole production line in order to be economically produced (Scahill, 1985). 6. Conclusions Results of this study successfully support the proposed model that provided the basis for the current study. The model may provide a theoretical framework Style variety
Table V. Summary of regression analysis
Standardized style New Style * Statistically significant at .05
F Value
p Value
0.99 5.46
0.32 0.02*
for future studies of apparel manufacturing. Besides its possible contribution to research, this study may also benefit practitioners. Dimensions of manufacturing strategy have been shown to be related to the use of sewing systems. Recognizing the influences of manufacturing strategies from the beginning to the end of the production process is valuable in product development and strategic planning for apparel manufacturers. The present research also has important implications from a statistical and methodological view. The AM model used in this study is extremely complex and difficult to estimate, particularly since mail survey of the apparel industry tend to have low response rates. Additional research is needed with a larger, more diverse sample of apparel manufacturers and with a larger variety of apparel manufacturers’ achievement and performance measures. Despite this limitation, the research provides some important information about the validity of production environment decisions for apparel manufacturers. On the most fundamental level, the study has demonstrated that significant information can be determined from an exploration of apparel manufacturing strategies and examination of the production environment. In this case, the value of the selected sewing systems has been questioned for a long time. The research has provided logical suggestions and has shown that the manufacturing strategies of U.S. apparel industry form an important repository for future research in this area.
References Aldrich, J.H. and Nelson, F.D. (1986), Linear Probability, Logit and Probit Models, 3rd., Sage Publications, Beverly Hills, CA. Abernathy, F.H., Dunlop, J.T., Hammond, J.H. and Weil, D. (1995), “A study of US apparel industry in transition”, Brookings papers on Economics Activity: Macroeconomics., Vol. 1, pp. 175-246. American Apparel Contractors Association, (1995), 1995-1996 Sourcing Guide, Atlanta, GA. American Apparel Manufacturers Association, (1986), Planning and Implementing an Apparel Sourcing Strategy, Arlington, VA. American Apparel Manufacturers Association, (1995), AAMA 1995 Directory, Arlington, VA. American Apparel Manufacturers Association, (1996), Focus: An Economic Profile of the Apparel Industry, Arlington, VA. American Business Information, (1996), 1996 American Big Business Directory, New York. Cabrera, A.F. (1994), “Logistic regression analysis in higher education: An applied perspective”, in Smart, J.C. (Eds), Higher Education: Handbook of the Theory and Research, Agathon Press, New York, Vol.10. Cooklin, G. (1991), Introduction to Clothing Manufacture, BSP Professional Books, London. Dillman, D.A. (1978), Mail and Telephone Surveys: The Total Design Method, John Wiley, New York. Ettlie, J.E. and Penner-Hahn, J.D. (1994), “Flexibility ratio and manufacturing strategy”, Management Science, Vol. 40, pp. 1444-54.
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Fischey, J.H. and Harrington, J.E. (1996), “Product variety and firm agglomeration”, RAND Journal of Economics, Vol. 27 No. 2, pp. 281-309. Gereffi, G. (1994), “The organization of buyer-driven global commodity chains: How U.S. retailers shape overseas production networks“, in Gereffi, G., Korzeniewicz, M. (Eds), Commodity Chains and Global Capitalism, Greenwood, Westport, CT pp. 95-122. Kotabe, M. (1992), Global Sourcing Strategy, Quorum, New York. Kim, Y. and Lee, J. (1993), “Manufacturing strategy and production systems: An integrated framework”, Journal of Operations Management, Vol. 11 No. 1, pp. 3-15. Ko, E. and Kincade, D.H. (1998), “Product line characteristic as determinants of quick response implementation for US apparel manufacturers”, Clothing and Textiles Research Journal, Vol. 16 No. 1, pp. 11-8. Lin, S., Kincade, D.H. and Warfield, C. (1995), “An analysis of sewing systems with a focus on Alabama apparel producers”, Clothing and Textiles Research Journal, Vol. 3, pp. 30-7. Meredith, J.K. (1981), “Style change: Its effects on operator earnings”, Bobbin, Vol. 23 No. 3, pp. 139-44. Mize, J.H. (1992), “Constant change, constant challenge”, in Heim, J.A., Compton, W.D. (Eds), Manufacturing Systems, National Academy, Washington, DC pp. 196-203. MacDuffie, J.P., Sethuraman, K. and Fisher, M.L. (1996), “Product variety and manufacturing performance: Evidence from the international automotive assembly plant study”, Management Science, Vol. 42 No. 3, pp. 350-68. Scahill, E.M. (1985), The Effect of Research and Development on U.S. Market Structure, UMI Research Press, Ann Arbor, MI. Solinger, J. (1988), Apparel Manufacturing Handbook, Bobbin Media Corporation, Columbia, SC. Schroeder, R.G. and Lahr, T.N. (1990), “Development of manufacturing strategy: A proven process”, in Ettlie, J.E., Bernstein, M.C., Fiegenbaum, A. (Eds), Manufacturing Strategy, Kluwer, Boston pp. 3-14. Swamidass, P.M. and Newell, W.T. (1987), “Manufacturing strategy, environmental uncertainty and performance: A path analytic model”, Management Science, Vol. 33, pp. 509-24. Taplin, I.M. (1994), “Strategic reorientations of U.S. apparel firms“, in Gereffi, G., Korzeniewicz, M. (Eds), Commodity Chains and Global Capitalism, Greenwood, Westport, CT pp. 205-22. The [TC]2 Manufacturing Team, (1995), “Workplace teams: What’s in it for you?”, Bobbin, Vol. 36 No. 6, pp. 48-52. Women Wear Daily, (1994), WWD Supplier’s Guide 1994. New York: Fairchild.
The current issue and full text archive of this journal is available at http://www.emeraldinsight.com/0955-6222.htm
Enabling mass customization: computer-driven alteration methods
Computer-driven alteration methods 61
Cynthia L. Istook Dept. of Textile and Apparel, Technology and Management, North Carolina State University, College of Textiles, Raleigh, NC, USA Keywords Manufacturing, Customization, Garments Abstract Manufacturers have been struggling to meet the wants and needs of their customers without sacrificing the efficiencies and profits gained through mass production. Fortunately, developments in information technology have increased the probability of mass customization being adopted as an acceptable business paradigm. Almost every CAD system used in apparel patternmaking has some method that would enable mass customization through automatic alteration of patterns based on individual measurements. Although each has created an interface somewhat differently from all of the others, most have a number of preparatory activities in common that will allow “automatic” alterations to occur. This article outlines the activities involved in setting up CAD systems to automatically customize garments for fit.
During this decade, the textile and apparel complex has been scrambling to adjust to a rapidly changing business environment. With increasing imports and rising labor rates, the industry has seen a drastic change in its appearance. Businesses have closed and employment within the US industry has decreased, as production of textile products moved offshore. Industry leaders have been forced to evaluate this business shift and the ultimate effect on the consumer to determine ways in which the US industry might regain, if not maintain, market share. This evaluation ultimately led to the paradigm of mass customization. Mass customization is broadly defined as the mass production of customized goods. Since Stan Davis coined the term in 1987 in his book Future Perfect, manufacturers have been struggling to meet the wants and needs of their customers without sacrificing the efficiencies and profits gained through mass production. Manufacturers have been understandably reluctant to throw out all of their comfortable production practices to completely re-engineer their businesses in order to respond to the needs of their customers. Meeting the needs of a target market of one appears to be a foolish endeavor when taken at face value. Fortunately, developments in information technology have increased the probability of mass customization being adopted as an acceptable business paradigm.
International Journal of Clothing Science and Technology, Vol. 14 No. 1, 2002, pp. 61–76. q MCB UP Limited, 0955-6222 DOI 10.1108/09556220210420345
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The role of information technology Information technology and automation are a vital part of mass customization because they constitute the connection between the consumer’s wants and needs and the ability of a manufacturer to create the products accordingly. Taking advantage of technological developments in combination with proximity to the target market is the differential advantage that domestically manufactured products have over foreign produced goods. However, while technology may enable mass customization efforts, the processes involved are far from automatic. A significant amount of “behind the scenes” effort is still required in order to provide the color selection and fit of each garment that might be requested by individual customers. The purpose of this paper is to explore the technologies that enable the customized fit of previously created garment designs. Alteration of garment patterns is an essential step in producing attractive and accurately fitting clothing from patterns that already exist. Traditionally, alterations have been done using measurements, achieved with a measuring tape, to be incorporated into a paper pattern using the slash, seam, or pivot methods (Liechty et al., 1992; Rasband, 1994). In teaching pattern makers the correct way to achieve a garment with fit, educators have instructed them to create a pattern with optimal fit in the beginning (based on individual measures) and not to alter existing patterns (Joseph-Armstrong, 2000; Hillhouse and Mansfield, 1948; Zamkoff and Price, 1997). Commercial CAD alteration systems have been developed that either (1) draft patterns directly according to body measurements, (2) use base patterns and apply a mathematical formula to change them to fit specific body measurements, or (3) use graded patterns in conjunction with sizing and alteration tables to alter patterns to fit a person with specific body measurements (Turner and Bond, 1999). Most pattern makers in the industry are not required to know how to alter their patterns because they have always produced garments to fit their company’s sizing system (defined in the form of the basic sloper) and not individual customers. In fact, many pattern makers have absolutely no idea exactly how body measurements directly relate to the development or fit of specific garments. With renewed interest in meeting the specific fit needs of consumers, many involved in the production of these garments are at a distinct disadvantage. Commercial CAD alteration systems are not only complicated, they also require a significant level of knowledge and practical experience not easily obtained. Little information is available in current literature concerning the alteration of existing garment patterns in conjunction with current technology.
Why now is the alteration of industry garment patterns becoming such an Computer-driven issue? The developments in new technologies, such as 3-dimensional body alteration scanning and digital printing, have the potential of enabling manufacturers to methods utilize mass customization business strategies that would allow them to more effectively meet the needs of specific customers. An essential key to the use of these enabling technologies is the ability of Computer-Aided-Design (CAD) 63 systems to integrate measurement information and make changes to patterns, as necessary, without permanently changing the basic, original garment pattern. Almost every CAD system used in apparel pattern making has some method that enables pattern alterations based on individual measurements. Although each has created an interface somewhat different from all of the others, most (Gerber Technologies, Lectra Systems, Investronica, and Assyst) have several preparatory activities in common that will allow “automatic” alterations to occur. Two other systems (PAD and Optitex) have attempted to enable automatic alterations in a slightly different manner, however, the basic underlying theory is the same. These preparatory activities are laborious in the beginning, but ultimately allow the automatic alteration of existing garment patterns. Figure 1 shows the common workflow and decision process involved in establishing the alteration process for all of the patterns used in any specific garment. This set of activities requires a strong knowledge of garment design, grading, and garment construction, as well as an understanding of how computer programs “think”. Required alteration activities When adjusting a set of patterns to assure the desired fit of a garment, the pattern maker must make a number of decisions related to how much each pattern needs to change and exactly where each pattern needs to change. For beginners who still may not have a mental picture of how the patterns work together to create a garment, this may be a very difficult process. Experienced pattern makers, however, tend to make the necessary decisions without much apparent thought. Experience has helped them develop a set of heuristics that guide them in making requisite changes very rapidly. Unfortunately, computer systems do not have the “experience” or background knowledge required allowing the rapid alterations that can be accomplished by an experienced tailor. Current CAD systems cannot learn by experience. However, once the heuristics have been defined within a CAD system, it can process the information and perform the function, much more rapidly, accurately, and consistently than the most experienced tailor. Step 1: Determine critical alteration points Garments are generally altered at grade points or cardinal points. Since a great deal of effort has been made previously to allow garment patterns to grow as the human body does, this makes sense. Therefore, critical alteration points are
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Figure 1. Alteration process in typical CAD programs
usually related to the human circumferential measurements of the neck, chest/bust, waist, hips, biceps, thigh, knee, and ankle, and the length measurements of arms, back of neck to waist, waist to hip, waist to knee, and waist to floor. However, since no ONE person is exactly average, normal grading methods leave much to be desired in relation to fit. Fortunately, CAD
systems have the ability to alter garment patterns exactly where they need to Computer-driven be altered, if set up correctly and determined in advance. For this to occur, the alteration tailor must determine where fit problems might occur in any specific garment, methods (high hip, seat, upper chest, above elbows, etc.) and may be required to add grade points to these locations.
65 Step 2: Develop point numbering/naming convention CAD software used to develop patterns is limited by the information it holds in relation to each pattern piece. When each pattern was originally created, it was merely a conglomerate of lines, curves, and points until the operator identified the parts that made the whole piece or block. Grade points were then labeled to identify growth locations for the computer. In order for a CAD system to perform alterations on a pattern, it must be able to identify each point by number or name and it must be able to differentiate between points so that the requested action does not cause confusion or occur inappropriately. When developing the numbering or naming convention, it is important to plan ahead so that future pattern preparations will be easier. One of the most time consuming activities in the CAD pattern alteration process is the development of a numbering convention and the application of that convention to the pattern pieces and in alteration rules. If a numbering convention is developed in advance, the tailor can take advantage of that process in all similar garment situations. For example, a numbering convention should be developed that can encompass a wide variety of pant styles, so that it can be used on every pant pattern in the line. The easiest way to do this would be to take the most complicated style in the line and work out a convention that would allow the most varied alterations to occur. When the resulting convention is applied to simpler garments, it is very likely that a successful alteration can occur. The first step in creating the numbering convention is to identify all of the garment categories that would have similar alterations performed on them. This might include categories such as tops, skirts (no legs), pants, dresses, etc. The first level of a numbering system would identify these categories. The second step is to get a layout of all of the pattern pieces used in the most complicated garment, such as the pants mentioned above. For a pair of jeans this might include a riser, left pant front, right pant front, pant back, left fly, right fly, pocket facing, bag pocket, patch pocket, and so on. If the most complicated pattern has nine pieces or fewer, the second digit in the numbering system would identify a specific part of the whole garment. If more than 9 pieces were required to create the garment, then two digits would be required to identify each part. The last step is to identify all of the points on any specific part of a garment that would be involved in the CAD alteration process. All grade points will need to be included in this process. Other points will need to be added, beyond
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those normally graded, to allow alterations to meet individual body shapes. The number system should be developed to allow for a consecutive number addition in between major points, if it becomes necessary. Table I shows how a numbering convention might work. It is important to note that some CAD systems allow the use of words to “name” each individual point. As can be seen in Table I, words or letters are probably much more difficult to control than numbers would be. Once the convention is determined, it must be physically applied within the CAD system to the appropriate point in the appropriate pattern piece. Exactly how this should be accomplished will depend upon the specific CAD system in use. Figure 2 provides an example of point numbers/names applied to a pattern piece. It is very important to understand that the point number will be used to tell the system how to alter a pattern. The system will try to perform the alteration at every location with the same number/name. This might be appropriate in some cases, but is likely to create difficult errors when the process is tested. A general rule of thumb, then, would be to insure that all point numbers/names within a piece are unique. Depending on the situation, it may also be important to insure that all point numbers within the entire garment are unique. Some CAD systems do not allow multiple points within a piece to have the same number, however, others provide no such control. Step 3: Develop alteration rules Grade rules must be created and applied to pattern pieces, in order to tell the computer how to make each piece increase or decrease in size. The grade rule numbers identify the location of a required action by the CAD system. These grade rules generally increase and decrease the size of a pattern in a very predictable, proportional way, from one size to the next (see Figures 3 and 4). As mentioned before, all alterations will generally occur at specific grade points. For the systems for which that is a requirement, new grade points may need to be developed in a garment to allow for growth of unusual body shapes.
Category
Part
Point
Tops Skirts Pants Right Front Left Front Back Table I. Example Numbering Convention
Waist/SS SS/High Hip SS/Hip SS/Thigh Dresses
Number 1 2 3 3 3 3 3 3 3 3 4
1 2 3 30 31 31 32
1 0 5 0
An example of a situation where this might be a requirement could include a Computer-driven person with a disproportionately small waist compared to her hips. In this case, alteration an additional grade point might be required at a high hip location methods (approximately 3 in. below the waist). Alteration rules are generally created for each body measurement considered “key” for the fit of a specific garment. The shift garment 67 demonstrated in Figures 2 – 4 above would have alteration rules for the bust, waist, hips, back waist length, and waist to knee length as “key” alterations. For women with significant fit problems, however, additional alteration rules might also be needed, such as across chest, across back, high hip, and combined thigh girth. The addition of each alteration rule beyond the initial “key” rules complicates the process for two important reasons. First, grade points and grade rules will need to be created, if none exist on those specific locations. Second, many of the CAD systems expect to use all of the alterations that are developed for a specific garment, every time the garment is ordered. If
Figure 2. Points numbered with unique names
Figure 3. Grade point locations
Figure 4. Graded nest
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only the initial “key” measurements are used (because of a lack of the other measurements or rather insignificant fit problems), the CAD system may fail to process the order at all. Within each alteration rule, instructions must be developed to control every point on a garment related to a specific location where an alteration should occur. For example, in the shift front pattern shown in the previous Figures 2, 3, and 4, there is a side seam waist point for each side of the garment, as well as waistline dart points that would be impacted by a waist alteration. The same points exist on the back pattern piece, as well. To increase the waistline by any amount, the measure would generally be evenly distributed at the 4 locations (1/4 or 25%) defined by the left front side seam waist, right front side seam waist, left back side seam waist, and right back side seam waist points. The front and back waistline darts would also receive half of the distribution allowed to each quadrant of the garment; 1/8 or 12.5% of the measure. As the structure of the garment gets more complicated, as with princess lines or asymmetrical constructions, the instructions for each alteration rule become increasingly more complicated. Instructions for alteration rules are based on types of movements that can be used to generate an alteration. The five types include: (1) Counter-clockwise, no extension [CCW No Ext], (2) Counter-clockwise, extension [CCW Ext], (3) Clockwise, no extension [CW No Ext], (4) Clockwise, extension [CW Ext], and (5) X and Y move [X Y move]. To provide control for these alteration movements, hold points and move points must generally be defined. In moves 1 and 2, the move point is counterclockwise on the pattern piece from the hold point. (See Figures 5 and 6) In the CCW Ext, the first alteration point is held stationary. Every point (going counter-clockwise from the first point) until the second (move) alteration point will move as the segment between the two point pivots. The pivoted line may
Figure 5. Move 1: CCW No Ext. The hold point is 2130 and the move point is 2120
lengthen or shorten as necessary to meet the adjacent line. The same is true for Computer-driven the CCW No Ext except that the pivoted line remains the same length as on the alteration unaltered pattern. methods In moves 3 and 4, the move point is clockwise from the hold point. (See Figures 7 – 9) For the CW Ext, the first alteration point is held stationary. Every point (going clockwise from the first point) until the second (move) alteration 69 point will pivot with the segment between the two points. The pivoted line may lengthen or shorten as necessary to meet the adjacent line. For the CW No Ext,
Figure 6. Move 2: CCW Ext. The hold point is 2130 and the move point is 2120
Figure 7. Move 3: CW no Ext. The hold point is 2120 and the move point is 2130
Figure 8. Move 4: CW Ext. The hold point is 2120 and the move point is 2130
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Figure 9. Move 3: CW no Ext. The hold point is 2125 and the move point is 2130
Figure 10. Move 5: XY Move. The hold and move points are both 2125 in a +Y direction
Figure 11. Move 5: XY Move. The hold point (1st point) is 2115 and the move (2nd point) is 2120 in a – X direction
the same is true except that the pivoted line remains the same length as on the unaltered pattern. In move 5, both points move the same amount. (See Figures 10 and 11.) For the XY move, the first and second alteration point, and all points in between (going clockwise from the first point to the second) move together in the X, Y, or XY direction. Beginning with one alteration rule at a time, identify all points that should be adjusted and determine the kind of move (CCW no Ext, CCW Ext, etc) that would be most appropriate for each. It is possible that more than one kind of move instruction could cause the same change in the pattern piece. For example in Figure 10, point 2125 could have been moved with an XY Move, a CCW Ext,
Computer-driven alteration methods 71 Figure 12. Alteration table for the Gerber Accumark system
a CW Ext, or a combination of two. In cases such as this, the best move can only be determined by trial and error. Once all of the alteration rules have been determined and the descriptions defined by point number, movement type, and amount, the information needs to be entered into the CAD system. In the Gerber Accumark system, this means the creation of an alteration rule table. (See Figure 12 for an example.) A more complicated alteration is with the bust area. In the shift, there is a bust dart and facing that must be accommodated in the move. The armholes in the front, back, front facing, and back facing along with the underarm-side seam point to the waist must move for an alteration. An example of an alteration rule for the bust can be found in Figure 13 with the affected patterns found in Figure 14.
Figure 13. Alteration table for the bust alteration
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Figure 14. Garment pieces with point numbers for alterations
Step 4. Verify alteration rules Every alteration rule that is created must be checked for accuracy before it is implemented. Most of the CAD systems have a feature allowing the operator to test the alteration rule. In the Gerber system, the “display piece” function enables each pattern piece to be viewed with an alteration rule applied. The operator should test each rule using an exaggerated measure, such as 2 in. (Figure 15). Once each rule has been tested on its own, then begin testing combinations of rules (see Figures 16 and 17). When all rules have been tested using a variety of measurements and combinations, as might occur in real life, you can feel fairly comfortable that the alteration rules have been created accurately, at least for this specific garment silhouette. Step 5: Determine physical measures for graded sizes Fit is a subjective term that describes how well a garment conforms to the expected shape on a person’s body. Above and beyond the generally accepted
Figure 15. Bust alteration rule tested on original pattern
practice by professionals to create garments that are balanced and have Computer-driven appropriate comfort ease, lies the personal preferences of each customer that alteration governs their perceptions of fit. Because of this, it has become very important methods for apparel manufacturers to communicate to their customers how each garment was designed to fit. Levi’s does a good job of communicating their jeans fit by both describing the fit and displaying a picture of the garment as it 73 was designed to fit on the tag attached to the garment. This communication is an essential step in having the ability to meet the fit expectations of the customers. However, every customer whose measurements differ from those for whom the garment was initially designed—most of the population, in fact—will be unable to achieve the same fit as previously communicated. At this point, it becomes important to know the exact measurements of the physical body for which the desired garments were created. This knowledge allows us to alter garments based on the specific difference between our customer’s measurements and the reference measurements that were used to create a garment that has the desired fit. Once the physical measures (at critical locations for a specific garment) have been determined for each of the graded sizes, a size code table needs to be created. A size code table contains a list of the measure names (such as bust, waist, hip, knee height, and back waist length) and the measurements for each specific size. An example of a size code table, as developed using the Gerber system, is shown in Figure 18. Step 7: Obtain the physical measure of the fit subject In order to create a custom fitted garment, you must have accurate physical measurements of the customer to use as a comparison against the “ideal” person for which the garment was initially designed. As body-scanning
Figure 16. Bust and waist alteration rules tested using 2 inch differences
Figure 17. Bust, waist, hips, dress length, and back waist lengths all tested using 2 inch differences
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technologies improve and become more readily available, this process will become quicker, more accurate, and less painful. Until that time, accurate physical measurements can be used as a basis for comparison. Most CAD systems base the alteration process on a comparison of the customer’s physical measurements with the measurements of the “ideal” person. In order to accomplish this the operator must determine the best match between the customer and the ideal person. In other words, which size garment would fit the customer best without alterations? Starting with a garment that most closely matches the customer’s expectations allows a smaller amount of change to occur and increases the likelihood of creating a more pleasingly shaped garment. Step 8: Create a size code table for the fit subject Once the “best” comparison size has been determined, a size code table must be created that included the measurements of the customer or “fit subject”. In the systems that have “made-to-measure” capabilities, the system itself may determine the “best fit” sizing and create a virtual table to be used when alterations are being performed. However, underlying all of this is the measurement table that allows the comparisons to be made (Figure 19). Step 9: Merge pattern with alteration rules and size code table When using CAD systems that have automatic made-to-measure (MTM) processes in place, the operator initially follows the previous 8 steps before the MTM system can be correctly setup. The MTM setup procedure involves identifying the specific alteration rules and size tables that apply for a specific garment pattern. In lieu of MTM software, most systems allow markers to be “ordered” using specific size tables and alteration rules. An example of this process using the Gerber system can be found in Figure 20.
Figure 18. Basic size code table for 3 of the graded sizes for a specific garment
Step 10: Process the merged marker order Computer-driven MTM systems often accomplish both steps 9 and 10 through a batch process, alteration creating a production marker for the custom fit garment automatically. In the methods background, however, the MTM system generates an order for a custom marker, processes the order, and automatically makes the marker. This process can be accomplished without the MTM system or other batch processes 75 through normal software functionality.
Step 11: Plot or cut the custom marker The final step in creating custom fit garments is to cut and produce the garment. When initially developing each of the parts of the automatic alteration system, the process should be tested and proven repeatedly, using a variety of people with diverse fit problems. Repeated trials help insure successful implementation and enable hidden errors to be found.
Figure 19. Customer size comparison table
Figure 20. Merging garment pattern with alteration rules and sizing tables
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Benefits of CAD Driven Alterations The mass production strategies that have driven apparel production for decades have negatively impacted the design and fit of clothing. These strategies have categorized whole populations by a relatively small number of sizing systems and made it virtually impossible to meet the needs of those individuals who have special fitting requirements. Computer-driven alteration methods will enable the creation of garments, customized for fit, in a very quick and accurate manner. These customized garments can be inserted into normal production lines as an additional “size” and produced like every other garment of the same style. CAD driven alterations methods also allow styles to be customized, repeatedly, without time consuming preparational activities. Since the development of a successful style may take many weeks, it is very important that proven styles be customizable without any additional input from designers or patternmakers. This means that successful companies with huge libraries of garment styles would be able to implement mass customization strategies with relatively little effort. The decrease in production numbers that would occur due to cutting one garment at a time, rather than hundreds, could be offset with increases in sales prices and customer loyalty. References Davis, S.M. (1987), Future Perfect, Reading, Mass, Addison-Wesley. Gerber Garment Technology (GGT), (1997), Accumark Applications Guide, Tolland, Ct. Hillhouse, M. and Mansfield, E. (1948), Dress Design: Draping and Flat Pattern Making, Houghton Mifflin Co., NY. Joseph-Armstrong, H. (2000), Patternmaking for Fashion Design, 3rd ed., Prentice Hall, NJ. Liechty, E.G., Pottberg, D.N. and Rasband, J.A. (1992), Fitting and Pattern Alteration: A Multimethod Approach, Fairchild, New York. Rasband, J.A. (1994), Fabulous Fit, Fairchild, New York. Turner, J.P. and Bond, T. (1999), “Made-to-measure garments for ladies—catering for wide ranging stature and length measurements for standard and outsize ladies”, International Journal of Clothing Science and Technology, Vol. 11 No. 4, pp. 216-25. Zamkoff, B. and Price, J. (1997), Basic Pattern Skills for Fashion Design, Fairchild Publications, NY.
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Thickness and compressional characteristics of air-jet textured yarn woven fabrics A. Mukhopadyhay
Received March 2001 Accepted October 2001
Senior Lecturer, The Technological Institute of Textile & Sciences, Haryana, India
A.K. Dash Research Scholar, The Technological Institute of Textile & Sciences, Haryana, India, and
V.K. Kothari Professor, Indian Institute of Technology, Department of Textile Technology, New Delhi, India Keywords Yarns, Compression, Woven fabrics Abstract The effect of pick density, constituent filament fineness and heat-setting on the fabric thickness and compressional properties have been studied before and after laundering. With the increase in pick density fabric thickness, compression and compressibility increases up to a certain extent. Coarser filament textured yarn fabric have higher thickness, compression and compressibility than that of finer filament textured yarn fabrics. Heat-set fabrics possess higher thickness, compression and compressibility than the grey textured yarn fabrics. However, fabric compressional recovery and resiliency are mainly influenced by the fabric pick density rather than the effect of heat-setting and filament fineness of constituent textured yarns. On laundering, fabric thickness, compression and compressibility improve particularly for the fabric of lower pick density. The effect of laundering is marginal on fabric compressional recovery and resiliency.
International Journal of Clothing Science and Technology, Vol. 14 No. 2, 2002, pp. 88-99. q MCB UP Limited, 0955-6222 DOI 10.1108/09556220210424198
Introduction Among several attributes, thickness and compressional properties of the fabric are very important characteristics in view of fabric handle. Compressibility is one of the most important properties for the fabrics used in garment manufacture. Fabric compressional characteristics depend on several factors like the compressional properties of the constituent warp and weft threads and the structure of the fabric. In earlier work (Dupuis et al., 1995; Sengupta et al., 1990), thickness and compressional behaviour of fabrics with various types of spun yarns with different compressional properties have been studied. The effect of fabric parameters on the thickness and specific volume of the fabric for a given air-jet textured yarn bulk has also been studied (Kothari et al., 2000). It should be noted that the efficacy of the texturing process depends upon its stable bulkier structure depending on its end use. The realisation of textured yarn bulk in
fabric could be influenced by numerous factors. In this regard, it is important to study the change in compressional properties of the fabrics made from textured yarns of different levels of bulk in relation to heat-setting. Further to judge the long term performance of the fabric, it is also important to study the above characteristics after a number of laundering cycles.
Thickness and compressional characteristics 89
Specimen preparation Plain woven fabric samples were prepared with 14.7 tex polyester-viscose (67:33) spun yarn warp. For weft yarns, two different materials, 70 denier/36 filament and 70 denier 72 filament drawn polyester filament yarns were textured on ELTEX AT/HS air-jet texturing machine. Two ends of parent yarns were fed together in a parallel-end air-jet texturing machine using HemaJet with T100 core. Details of the process parameters used in the production of air-jet textured yarn are as follows: Overfeed to jet: 26.7 per cent Air Pressure: 900 kPa Texturing speed: 300 m/min Amount of water used per jet: 1 litre/hr Water pressure: 2 kgf/cm2 Stabilising stretch: 4.7 per cent Stabilisation heater temperature: 1808C Winding underfeed: 0.7 per cent The linear densities of 70 denier/72 filament and 70 denier/36 filaments textured yarns were 17.44 tex and 17.54 tex respectively. Four different pick densities (24.4, 27.6, 30.7, 33.9 picks/cm) were used on the loom and the fabrics were heat-set on a stenter at 1808C temperature and 20 m/min. speed with 3 per cent overfeed, allowing 5.1 per cent widthwise shrinkage. Both the grey and heat-set fabrics were laundered in a washing machine under the following conditions: Bath composition: 5 g/l soap solution Temperature: 258C Time/cycle: 15 minutes washing Rinsing and drying: 15 minutes rinsing followed by 5 minutes drying Material and liquor ratio: 1:50 The fabric samples were dried centrifugally after every laundering cycle. Based on an initial trial, fabrics were subjected to 20 laundering cycles so that further to this no significant changes occur in the above fabric
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characteristics. Before taking measurements, all the samples were pressed by a steam press and conditioned for 24 hours. The fabric particulars are given in Table I. The physical bulk of textured yarn was measured by package density method using spindle driven winder on the basis of equal diameter of 25 mm. The bobbins were built on empty package of 12.16 mm outer diameter with 60 mm traverse. The average winding tension was adjusted to 0.3 gf/tex. The physical bulk of coarser filament (2.16 dtex) and finer filament (1.08 dtex) textured yarns was 237 g/tex and 213 g/tex respectively. Fabric thickness was measured on an Instron (Model 4411) tester in compressional mode, using a compression plate of 49 mm diameter and compression rate of 1.2 mm/min. Thickness values at different pressure levels viz. 5 gf/cm2, 20 gf/cm2 and 50 gf/cm2 were obtained. The compression, compressibility, compressional recovery and the resiliency behaviour were studied by extending the jaw movement distance in the graph (which is plotted on x-axis) as shown in the Figure 1. The following parameters are obtained from the equations given below: Compression ðmmÞ ¼ t0 2 t f
Fabric particulars without laundering Sample code
Table I. Textured yarn woven grey and heat-set fabric particulars with and without laundering
ends/cm
picks/cm
GT GT GT GT GT GT GT GT
72/62 36/62 72/70 36/70 72/78 36/78 72/86 36/86
36.2 36.0 36.0 36.0 36.0 36.0 36.3 36.2
24.2 24.4 27.3 27.7 30.4 30.6 33.9 33.9
HT HT HT HT HT HT HT HT
72/62 36/62 72/70 36/70 72/78 36/78 72/86 36/86
37.8 37.2 37.8 37.0 38.0 37.4 38.0 37.6
26.2 26.6 28.6 28.7 31.5 31.6 34.0 34.0
Weight (g/m2) Grey fabrics 103.6 101.8 106.5 105.9 113.9 112.3 120.0 118.1 Heat-set fabrics 110.7 108.2 114.8 114.7 118.2 117.8 120.8 119.0
Fabric particulars with laundering ends/cm
picks/cm
Weight (g/m2)
37.4 37.6 37.4 37.4 37.1 37.6 37.0 37.8
25.6 25.8 28.4 28.6 31.0 31.1 34.0 34.0
111.0 110.6 113.2 113.0 119.4 117.8 120.7 119.3
38.0 37.6 37.9 37.4 38.4 37.4 38.4 37.6
26.6 27.0 28.9 29.0 31.8 31.9 34.0 34.0
112.6 110.8 114.7 114.5 118.6 117.9 120.9 119.0
G – Grey, H – Heat-set, T – Textured, Nominal end density – 36 ends/cm, Nominal pick density varying between 62 to 86 picks/inch.
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Figure 1. Compression and recovery graph obtained on INSTRON tester
Compressibility; ð%Þ ¼
t0 2 tf £ 100 t0
Thickness recovery; ð%Þ ¼
tr £ 100 t0
Compressional energy ¼ f £ ðW 1 Þ Recovered energy ¼ f £ ðW 2 Þ Resiliency ð%Þ ¼
W2 £ 100 W1
Where, t0 is the initial thickness, tf is the final thickness after the fabric is compressed, tr is the thickness obtained after the fabric recovered from the compressed state after 1st cycle, W1 is the weight of the chart paper of the area below the compression curve, W2 is the weight of the chart paper of the area below the recovery curve, and f is the conversion factor.
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Discussion of results Effect of pick density, constituent filament fineness and heat-setting on fabric thickness before and after laundering Figures 2 and 3 show the effect of pick density on fabric thickness at different levels of pressure. It is observed that fabric thickness increases up to a certain extent with the increase in fabric pick density, particularly when the thickness is measured at lower pressure level. At higher pressure levels, changes in fabric thickness due to the change in pick density is very small. The above finding is in agreement with the earlier finding (Kothari et al., 2000). It is also noted that the textured yarn fabric thickness is higher after heat-setting for both laundered and unlaundered fabrics. The thermal shrinkage during the heatsetting leads to increase in fabric thickness. It is further observed that the difference in thickness values of grey and heat-set fabrics is much higher at 5 gf/cm2 pressure compared to that of 20 gf/cm2 and 50 gf/cm2 pressure during the thickness measurement. It is noted from the Figures 4 and 5 that the thickness of laundered fabric is significantly higher than that of unlaundered fabrics at lower pick density and at lower pressure. Further after laundering, change in thickness with increase in pick density is very marginal. The changes in thickness with the increase in pick density depend upon relative and absolute values of crimp amplitudes of warp and weft threads, diameters of warp and weft yarns, compressibility of threads in the fabric structure and the surface irregularity of the fabric. After laundering, pick density increases particularly for the fabric of lower pick density leading to greater dimensional change of the said fabric. It is also observed from the above figures that thickness of coarser filament textured yarn fabric is higher than that of finer filament textured yarn fabric before and after laundering. This is due to the higher yarn bulk of coarser filament textured yarn as compared to finer filament textured yarn. It is further observed that the effect of laundering is more on heat-set fabric particularly for the fabric at lower pick density. Effect of pick density, constituent filament fineness and heat-setting on fabric compression and compressibility before and after laundering Table II shows that with the increase in pick density the compression of fabric increases up to a certain level of picks/cm for both grey and heat-set textured yarn fabrics before and after laundering. However, the compression values of laundered fabrics is significantly higher than that of unlaundered fabric at lower pick density for both the above said fabrics. It is further observed that the coarser filament textured yarn fabric has higher compression values than that of finer filament textured yarn fabric before and after laundering. This is due to the higher bulk of coarser filament textured yarn which provides greater compression. On heat-setting the difference in compression values of finer and
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Figure 2. Effect of pick density on thickness of coarser filament textured yarn fabric at different pressures without laundering
Figure 3. Effect of pick density on thickness of finer filament textured yarn fabric at different pressures without laundering
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Figure 4. Effect of pick density and constituent filament fineness on thickness of grey textured yarn fabrics before and after laundering
Figure 5. Effect of pick density and constituent filament fineness on thickness of heat-set textured yarn fabrics before and after laundering
coarser filament textured yarn fabric became lower. It is also noted that, in general, the fabric compression is higher for heat-set fabric before and after laundering. The effect of heat-setting is much higher than the effect of laundering. Table II and Figures 6 and 7 show that with the increase in pick density, the compressibility of both coarser and finer filament textured yarn grey and heatset fabrics increase only up to a certain picks/cm. After laundering, fabric compressibility becomes higher for the fabric of lower pick density. From the same figures it is observed that, on heat-setting the difference in compressibility values of finer and coarser filament textured yarn fabric reduces. The above reduction in difference in compressibility of finer and coarser filament textured yarn fabric is also shown by the fabric compression results (Table II). After heat-setting there is an increment in compressibility of both coarser and finer filament textured yarn fabric with and without laundering (Table II). This may be attributed to increase in compressible part of the fabric after heat-setting. The effect of laundering on fabric compressibility is much lower than the effect of heat-setting. Effect of pick density, constituent filament fineness and heat-setting on compressional recovery and resiliency before and after laundering Table II and Figures 8 and 9 show that with the increase in pick density the recovery and resiliency of both grey and heat-set laundered and unlaundered textured yarn fabrics increase. This may be attributed to the increase in number of cross-over points of warp and weft threads within the compression zone of the fabric which results greater mass of fabric contributing towards compressional recovery and resiliency. From the same figures it is observed that constituent filament fineness has little influence on recovery and resiliency both before and after laundering. However, after laundering the fabric compressional recovery and resiliency increases slightly for both the coarser and finer filament textured yarn fabric. Further, it is observed that heat-setting has little influence on both the compressional recovery and resiliency for coarser and finer filament textured yarn fabric (Table II). Conclusions With an increase in pick density of textured yarn fabric, the fabric thickness increases up to certain extent when thickness is measured at lower pressure. At higher pressure, the effect of pick density on fabric thickness is marginal. However, after laundering the effect of pick density on thickness is marginal at all pressures. The difference thickness values of grey and heat-set fabric is much higher at 5 gf/cm2 pressure compared to that of 20 gf/cm2 and 50 gf/cm2 pressure both before and after laundering.
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Table II. Effect of pick density, constituent filament fineness and heat-setting on fabric compressional parameters
0.076 0.104 0.121 0.118
0.110 0.119 0.120 0.120
0.143 0.174 0.185 0.179
0.193 0.204 0.204 0.197
24 28 31 34
24 28 31 34
24 28 31 34
24 28 31 34
Pick density, picks/cm (Nominal)
96
0.148 0.160 0.159 0.150
0.114 0.148 0.167 0.165
0.054 0.070 0.069 0.066
0.036 0.050 0.066 0.066
22.1 28.5 31.1 31.5
Grey fabrics 12.0 19.7 22.3 23.3 Grey laundered fabrics 29.0 16.9 30.7 21.5 31.4 21.9 32.1 22.0 Heat-set fabrics 33.0 28.2 35.4 34.5 37.6 37.6 38.5 37.7 Heat-set laundered fabrics 39.8 37.0 40.5 38.2 41.2 39.0 40.8 38.0 86.2 91.6 94.7 96.8
83.5 86.1 89.1 95.0
83.8 87.8 91.8 96.8
80.0 84.9 88.0 94.0
87.9 92.9 95.0 97.0
84.0 87.0 90.7 95.9
85.7 89.7 93.6 96.2
81.1 85.0 88.6 94.1
70.1 74.7 78.7 84.8
68.4 71.4 75.3 82.7
68.1 72.1 75.3 83.9
66.4 71.4 74.9 81.9
71.1 74.9 78.7 85.9
69.1 71.5 75.4 82.8
69.9 72.1 76.1 84.0
67.1 71.3 75.6 82.7
Compression (mm) Compresibility (per cent) Recovery (per cent) Resiliency (per cent) Finer Coarser Finer Coarser Finer Coarser Finer Coarser filament filament filament filament filament filament filament filament textured yarn textured yarn textured yarn textured yarn textured yarn textured yarn textured yarn textured yarn fabric fabric fabric fabric fabric fabric fabric fabric
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Figure 6. Effect of pick density and consntuent filament fineness on compressibility per cent of grey textured yarn fabrics before and after laundering
Figure 7. Effect of pick density and constituent filament fineness on compressibility per cent of heat- set textured yarn fabrics before and after laundering
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Figure 8. Effect of pick density and constituent filament fineness on recovery per cent of heat-set textured yarn fabrics before and after laundering
Figure 9. Effect of pick density and constituent filament fineness on resiliency per cent of heat-set textured yarn fabrics before and after laundering
With the increase m fabric pick density, fabric compression and compressibility increase up to a certain extent. Fabric compressional recovery and resiliency are mainly influenced by fabric pick density rather than the effect of heatsetting and filament fineness of constituent textured yarns. On heat-setting, the textured yarn fabric possesses higher thickness, compression and compressibility than that of grey textured yarn fabrics with little difference in compressional recovery and resiliency. Coarser filament textured yarn fabrics have higher thickness, compression and compressibility than that of finer filament textured yarn fabrics but there is no significant difference in fabric recovery and resiliency. On laundering, fabric thickness, specific volume, compression and compressibility improve particularly for the fabric of lower pick density. However, the effect of laundering is marginal on fabric compressional recovery and resiliency. References Dupuis, D., Popov, G. and Viallier, P. (1995), “Evaluation of grey state fabrics as a function of yarn structure”, Textile Research Journal, 65, pp. 309-16. Kothari, V.K., Mukhopadhyay, A. and Kaushik, R.C.D. (2000), “Bulk characteristics of air-jet textured yarn woven fabrics”, Indian Journal of Fibre & Textile Research, 25, pp. 37-41. Sengupta, A.K., Kothari, V.K. and Srinivasan, J. (1990), “Effect of repeated laundering on the properties of air-jet textured cotton/filament composite fabrics”, Textile Research Journal, 60, pp. 573-9.
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Effect of clothing pressure on the tightness sensation of girdles A.P. Chan and J. Fan
Received August 2000 Accepted November 2001
Institute of Textiles and Clothing, The Hong Kong Polytechnic University, Hong Kong Keywords Clothing, Effectiveness Abstract Girdles should be designed to beautify the lower body part of a woman without creating any discomfort and detrimental physiological effects. This paper reports on an experimental investigation into the relationship between the subjective tightness sensation and the clothing pressure of girdles. The subjective tightness sensation is a measure of the effectiveness of girdles, since too loose means the girdle is not effective in shaping the body and too tight means it is not comfortable and may have detrimental physiological effects. Based on this experimental investigation, the effect of clothing pressure on the tightness sensation is better understood and the optimum pressure distribution of girdles, which is an important criterion for product development and evaluation of girdles, is proposed.
International Journal of Clothing Science and Technology, Vol. 14 No. 2, 2002, pp. 100-110. q MCB UP Limited, 0955-6222 DOI 10.1108/09556220210424215
Introduction Girdle is a type of pressure foundation wear worn by women to re-shape the lower part of the body by uplifting the hips and compressing the abdomen so as to enhance the aesthetic appearance of the wearer. The functional requirements of girdles are very demanding. While shaping the women’s lower part of the body, it should not create discomfort and any detrimental effects on wearer’s physiology. The effects of wearing girdles on wearer’s physiology were investigated by a number of researchers. Watanuki (1994), who evaluated the degree of blood disturbance from wearing girdles by the cardiac output. It was found that the cardiac output decreased linearly with the increase in the pressure applied to the groin. Redesigning the bandage attached to the groin with a new shape and material reduced the pressure and hence decreased in the cardiac output. Nagayama et al. (1995) reported that wearing a hard-type girdle could produce significant cardiovascular responses in terms of blood pressure and heart rate accompanied by the change in the balance of sympathetic and parasympathetic nervous activity. The wearing comfort of girdles is affected by pressure, touch, fitness and hot/wet feelings. Ikuta (1970) investigated the effect of the size difference and found that the smaller the girth of the foundation wear in comparison with that of the body, the hotter the wearer feels, and a greater sense of perspiration and tightness. Yamana et al. (1988) revealed that the wearing comfort of soft,
medium and hard girdles were very different. Soft girdles, although not so good Effect of clothing in body shaping, were more comfortable to wear and therefore preferred by pressure women students. Ito et al. (1995) found that total comfort of girdles were correlated with the sensation of softness, smoothness and touch of the girdle. Inamura et al. (1995) reported that the wearing comfort of girdles were related to the tensile and shear properties the girdle fabrics. 101 The pressure created by wearing girdles is an important parameter as it closely relates to body shaping, wearer’s physiological effects and wearing comfort. Makabe et al. (1991) conducted pressure measurements on subjects wearing girdles of various design, materials, pattern and construction. They found that subjects complained of discomfort when the pressure reached more than 30 , 40 mmHg: The relationship between the pressure sensation and clothing pressure was studied by Okada (1995). He found that the pressure sensation at the waistline was linearly related to the logarithm of the pressure applied by a waist cuff band, following the Weber-Fechner Law. As for the clothing pressure of girdles, Ito et al. (1995) found that there were only weak to moderate relationships between the sense of compression and clothing pressure of girdles at the waist, abdomen, hip and thigh lines. The effects of dynamic clothing pressure were recently investigated by Sasaki et al. (1997), who showed that the measured clothing pressure corresponded to the tightness sensation. For the product development and evaluation of girdles, it is important to establish the optimum clothing pressure distribution of girdles at various body positions. The optimum pressure distribution should be such that it maximally beautifies the lower body part of a woman without creating any discomfort and detrimental physiological effects. Despite of considerable published research work in the Japanese literature on the wearing comfort of girdles, the optimum pressure distribution is still not well established. The present study aims at establishing the optimum pressure distribution through an experimental investigation into the relationship between the subjective tightness sensation and clothing pressure of girdles. The subjective tightness sensation is used in this work to provide a simplified measure of the effectiveness of girdles, since too loose means the girdle is not effective in shaping the body and too tight means it is not comfortable and may have detrimental physiological effects. Experimental Girdle samples Nine girdles were obtained for the experiments. The details of the samples are listed in Table I. Human subjects Six female university students were invited to act as human models in the experiments. The details of the six human models are shown in Table II.
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Pressure measurement device We used the SD500 digital skin evaluator to measure the clothing pressure. It is a portable device consisting of two main parts: a LCD display and a balloon type sensor (See the photos in Figure 2). The sensor can be in different sizes. We used the one of 10 cm in diameter for good reproducibility. The sensor has an air cushion, which contains platinum wires on the two sides of its inner surface. During testing, the sensor is firstly inserted in between the skin and clothing, and air is pumped into the cushion so that the electrical contact of the platinum wires is disconnected. As the clothing pressure pushes the air out of the cushion, the cushion becomes flat and the platinum wires makes the electrical contact. As soon as the electrical contact takes place, the pressure shown on the LCD display is memorized and recorded. Measurement positions Pressures were measured at 10 different positions on the standing models as shown in Figure 3.
Table I. Details of girdle samples
Table II. Details of the six human models
Figure 1. Three different brands of girdle
Sample No.
1
2
3
4
5
6
7
8
9
Brand Size
A 64
A 70
A 76
B 60
B 65
B 75
C S
C M
C L
Human Model
Waist Girth
Tummy Girth
Hips Girth
Height
Weight
Age
75 cm 64 cm 62 cm 61 cm 67 cm 59.5 cm
88 cm 78 cm 79 cm 75 cm 79 cm 81 cm
91 cm 87 cm 84 cm 93 cm 91 cm 87 cm
160 cm 161 cm 163 cm 163 cm 157 cm 156 cm
118 lbs 106 lbs 104 lbs 100 lbs 100 lbs 94 lbs
24 24 25 29 22 21
1 2 3 4 5 6
Experimental procedures Effect of clothing The nine girdles were conditioned under the standard laboratory condition pressure (228C and 65 per cent R.H) for over 24 hours before wearing tests. Each model was explained of the experimental procedure and the meaning of tightness rating. She was asked to wear the nine girdles for pressure measurement and rate the tightness at the 10 body positions. Figure 4 shows 103 a model’s lower body during pressure measurement. The tightness was rated in 1 to 7 scale (i.e. 1 ¼ very tight, 2 ¼ quite tight, 3 ¼ tight but acceptable, 4 ¼ comfortable; 5 ¼ loose but acceptable, 6 ¼ quite loose, 7 ¼ very loose). In
Figure 2. SD 500 digital skin evaluator
Figure 3. The ten measurement positions
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the preliminary experiment, it was found that model No. 1 varied her rating within the 30 minutes after wearing the girdle. Consequently, the tightness sensation was rated 45 minutes after wearing the girdle. Results and discussion Reproducibility of pressure measurement According to Niwaya et al. (1990) and Ono (1968), the accuracy and reproducibility of many pressure sensors are a serious problem, when used for measuring garment pressure on human body. The accuracy and reproducibility of the pressure device SD500 digital skin evaluator used in this work was therefore considered. To ensure the accuracy, the pressure measurement device was calibrated by a standard device, which is commonly used to measure blood pressure. Better control during measurements should also provide greater accuracy and reproducibility. The human models were asked to stand erectly with both legs straight. They were not allowed to shake their bodies until finishing of each in-between pressure assessment. The human models were also required to carry a normal breath instead of deep breath. The aim of standing erectly was to ensure the even pressure distribution of measured point. If the human model shakes her body or change her posture during measurement, the pressure reading from apparatus will be affected. Besides, when the human model took a deep breath rather than a normal breath, the two side metal plates of the balloon typed sensor would contact to each other at the wrong time. Consequently, the wrong pressure reading would result, which would increase the variation of pressure measurement at each location. Five repeated pressure measurements were made. The distribution of the CV (i.e. coefficient of variation) of the pressure measurements are shown in Figure 5. As can be seen, 76 per cent of the measurements had CV ranged from 0 per cent to 6 per cent. There was only 23 out of 540 (4 per cent) measurements having CVs over 10 per cent. This confirmed the reproducibility of the measurements.
Relationship between tightness rating and clothing pressure Effect of clothing According to the Web-Fechner Law, human sensation is linearly related to the pressure logarithm of the physical stimuli, the tightness rating is plotted against the logarithm of the measured pressure. Figures 6 – 15 plot the relationships at the ten different positions. The correlation was the strongest at the waistline, with R2 being 0.56. The lowest correlation was found at the front tummy with a 105 R2 of 0.24. The other R2 values are between 0.3 to 0.4. In general, there is only moderate linear relationship between human tightness sensation rating and logarithm of clothing pressure on human skin. The effect of clothing pressure on pressure sensation at the waistline was previous investigated by Okada (1995), who found that there was a strong linear relationship between the pressure sensation and the logarithm of clothing pressure at the waistline. The relatively lower linear relationship found in our work may be due to the following reasons:
Figure 5. CV per cent of repeated pressure measurements
Figure 6. Tightness rating v.s. logarithm of pressure at left front tummy
Figure 7. Tightness rating v.s. logarithm of pressure at front tummy
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(1) The tightness rating is different from the pressure sensation. The pressure sensation in Okada’s work is purely a pressure feeling, whereas the tightness rating in our work is the adequacy of the pressure in terms of shaping the body and wearing comfort. As a result, the tightness rating is not entirely dependent on the clothing pressure.
106
(2) In Okada’s work, pressure was only applied to the waistline, so the pressure sensation at the waistline was not influenced by the pressure sensation at other locations. However, in our work different pressures were imposed onto the various parts of the body by wearing the girdle. When the wearer was asked to rate the tightness at a particular position, her rating may be influenced by the sensation at other positions.
Figure 8. Tightness rating v.s. logarithm of pressure at right front tummy
Figure 9. Tightness rating v.s. logarithm of pressure at left side
Figure 10. Tightness rating v.s. logarithm of pressure at right side
(3) Okada used the average pressure sensation of 28 subjects to relate to the Effect of clothing clothing pressure. Whereas, in our work each individual’s tightness pressure rating was plotted against the logarithm of the pressure. It is understandable that different people may have different response to pressure. (4) The tightness rating may be influenced by factors, such as human fat, resilience of muscle and human bone structure, in addition to pressure.
107
Our findings are more in line with the results of Ito et al. (1995), who investigated relationships between the sense of compression and clothing
Figure 11. Tightness rating v.s. logarithm of pressure at left front lower
Figure 12. Tightness rating v.s. logarithm of pressure at right front lower
Figure 13. Tightness rating v.s. logarithm of pressure at left hips
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pressure of girdles at the waist, abdomen, hip and thigh lines. They found that there were only weak to moderate relationships between the sense of compression and clothing pressure. It is important to realize the difference between the tightness rating, pressure sensation and sense of compression, although they look very similar. Tightness rating is a degree of adequacy in terms of body shaping and wearing comfort, pressure sensation is purely a pressure feeling, and sense of compression is a combination of compressive deformation and pressure. Optimum clothing pressure distribution of girdles The optimum clothing pressure distribution of girdles may have two interpretations: the optimum clothing pressure distribution for an individual and that for a group of people. The latter is the pressure distribution, which may not be ideal to each one, but is satisfied by the majority of people in the group. Since the body shaping requirements and wearing comfort of each individual is different, the optimum clothing pressure distribution of one individual is generally different from that of another individual. Based on the experimental findings in this work, the optimum pressure distribution of individuals cannot be established, instead we are aimed at establishing the optimum clothing pressure distribution for a group of people. From Figure 6 – 15, it can be seen that the pressure corresponds to the tightness rate 4 (comfortable) varies considerably among the six models and
Figure 14. Tightness rating v.s. logarithm of pressure at right hips
Figure 15. Tightness rating v.s. logarithm of pressure at waist level
when wearing different girdles. The pressure, which most people consider to be Effect of clothing at least acceptable is the average of the pressures corresponding to tightness pressure rate 4 (comfortable) of each models when wearing different girdles. The optimum pressure the ten different positions are calculated and listed in Table III. As can be seen, most people can accept relatively greater pressure at the two sides and prefer lower pressure at the hip. 109 Manufacturers can use the optimum clothing pressure distribution as a criterion to ensure that the newly developed girdles to have the pressure distribution, which most people in the designated size range find satisfactory. They can test the girdles on a dummy to see whether the pressure distribution matches or close to the optimum pressure distribution.
Conclusions The clothing pressure distribution of girdles is very important to the function of girdles in terms of body shaping and wearing comfort. In this paper, the effects of clothing pressure on the tightness rating as a subjective measure of the appropriateness of the girdles are considered and experimentally investigated. It was found that there is moderate linear relationship between the tightness rating and the logarithm of clothing pressure. The optimum clothing pressure at the ten different positions, proposed in this study, is useful to girdle manufacturers in product development and evaluation. The tightness rating may not only related to clothing pressure, but also to factors such as body size, human fat, resilience of muscle and human bone structure. Further investigation with the consideration of these additional factors would provide better understanding. Furthermore, other subjective sensations such as tactile feeling, hot/wet feelings, etc. and objective measures such as the change of body shape could be used in future work to evaluate the effectiveness of girdles.
Position Front Tummy Left Front Tummy Right Front Tummy Left Side Right Side Left Front Lower Right Front Lower Left Hips Right Hips Waist Level
Optimum Pressure (mmHg) 7.03 9.2 9.15 11.98 11.57 7.34 7.5 4.34 4.37 6.47
Table III. Optimum clothing pressure of girdles at different positions
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References Ikuta, N. (1970), “Hygienic Studies of Foundation Garments Part 1. Effects on Subjective Observations, Clothing Climate and Clothing Observation”, Japanese Journal of Hygiene, 25 No. 4, pp. 344-9. Inamura, A., Nakanishi, M. and Niwa, M. (1995), “Relationship between Wearing Comfort and Physical Properties of Girdles”, Journal of the Japan Research Association for Textile EndUses, 36 No. 1, pp. 109-18. Ito, N., Inoue, M., Nakanishi, M. and Niwa, M. (1995), “The Relation Among the Biaxial Extension Properties of Girdle Cloths and Wearing Comfort and Clothing Pressure of Girdles”, Journal of the Japan Research Association for Textile End-Uses, 36 No. 1, pp. 102-8. Makabe, H., Momota, H., Mitsuno, T. and Ueda, K. (1991), “A study of Clothing Pressure Developed by the Girdle”, Journal of the Japan Research Association for Textile End-Uses, 32 No. 9, pp. 424-38. Nagayama, Y., Nakamura, T., Hayashida, Y., Ohmura, M. and Inoue, N. (1995), “Cardiovascular Responses in Wearing Girdle – Power Spectral Analysis of Heart Rate Variability”, Journal of the Japan Research Association for Textile End-Uses, 36 No. 1, pp. 68-73. Niwaya, H., Imaoka, H., Shibuya, A. and Aisaka, N. (1990), “Predicting Method of contact Pressure of Fabrics”, Sen-I Gakkaishi, 46 No. 6, pp. 229-36. Ono, S. (1968), “Studies on the Hygiene of Underwear Clothing Part 3. Measurement of Clothing Pressure”, Japanese Journal of Hygiene, 22 No. 6, pp. 581-9. Okada, N. (1995), “Clothing Pressure and Pressure Sensation in Waist Line”, Journal of the Japan Research Association for Textile End-Uses, 36, pp. 146-53. Sasaki, K., Miyashita, K., Edamura, M., Furukawa, T., Shimizu, Y. and Shimizu, H. (1997), “Evaluation of Foundation Comfort Based on the Sensory Evaluation and Dynamic Clothing Pressure Measurement”, Journal of the Japan Research Association for Textile End-Uses, 38 No. 2, pp. 109-14. Watanuki, S. (1994), “Improvements on a Design of Girdle by Using Cardiac Output and Pressure Sensation”, Annuals of Physiological Anthropology, 13 No. 4, pp. 157-65. Yamana, N., Okabe, K., Sindo, K. and Kusumoto, K. (1988), “A study on Wearing Comfort of Girdles”, Journal of the Japan Research Association for Textile End-Uses, 29 No. 5, pp. 199-204.
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Optimising the number of layers in firefighters’ hoods James R. House Senior Scientific Officer (Physiology), Institute of Naval Medicine (Royal Navy), Gosport, United Kingdom
James D. Squire Higher Scientific Officer, Textile Development Scientist, Ministry of Defence, Bicester, United Kingdom, and
Firefighters’ hoods
111 Received March 2001 Revised March 2001 Accepted August 2001
Ronald Staples Higher Scientific Officer, Textile Development Scientist, Ministry of Defence, Bicester, United Kingdom Keywords Protective clothing, Fire Abstract To optimise protection from fire afforded to the head, an investigation into layering of firefighters’ hoods was undertaken. Hoods made from 1 to 4 layers of Kermel/FR Viscose (50 per cent blend) were flame challenged for up to 10 seconds (53 kW m2 2 to 85 kW m2 2) on a manikin head. Protection was increased with more layers. After four seconds of flame it was predicted that 74 per cent of the head suffered 28 or 38 burns with a 1-ply hood. This fell to 59 per cent and 45 per cent respectively, when a breathing apparatus mask and helmet were also worn. For a 4-ply hood corresponding predicted burns fell to 13 per cent, 8 per cent and & 8 per cent. Between 50 per cent to 67 per cent of these reductions occurred using a 2-ply hood, and 80 per cent with 3-ply. In conclusion, the most appropriate benefit was gained by adopting a 2-ply hood. Three or more layers interfered with helmet fitting and communications, and offered little increased benefit.
Introduction The Royal Navy (RN), like most other organisations employing firefighters, provides its personnel with a flame-retardant (FR) hood as part of their personal protective equipment. Until recently, RN firefighters used singlelayered Probanw treated cotton ‘anti-flash’ hoods, these are also provided to all ships’ crews as part of the FR protective clothing ensemble worn during conflict (termed action dress ). Previous work has demonstrated that the antiflash hood provides good protection against weapons flashes and small fuel explosions, and is appropriate for general use, but does not provide sufficient protection for firefighters (House, 1998). The anti-flash hood was not designed to fit properly around the breathing apparatus (BA) mask, leaving vulnerable areas of exposed skin (House, 1998). Of concern was the finding that the head was the least well-protected area of the firefighter’s body. Fatal head burns could occur before other areas of the body would suffer a burn, although protection was enhanced when a BA mask and helmet were worn (House, q British Crown Copyright
International Journal of Clothing Science and Technology, Vol. 14 No. 2, 2002, pp. 111-118. MCB UP Limited, 0955-6222
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1998). Consequently, a programme was initiated to develop a hood that provided enhanced protection and increased the survivability of firefighters exposed to extreme emergency conditions, such as a flashover or large-scale fuel explosion. These events are considered to have heat exposures in the range 80– 135 kW m2 2 with a duration of up to 5 seconds, although more usually they last 2 seconds or less (for review see House, 1998). Although it is obvious that the greater the number of layers of FR material (and air) used for a hood the greater the protection, it is not possible to simply provide a multi-layered hood as there are other conflicting constraints. As the number of layers increases, so too does the size of the helmet required to accommodate the increased size of the hooded head. Without special (and very expensive) sizing of helmets, thick or multi-layered hoods will result in many firefighters being unable to fit into even the largest of the normal size range of most manufacturers’ helmets. Furthermore, a new helmet mounted communications system was being introduced into the RN, which uses a bone conduction microphone mounted inside the top of the helmet. As the thickness or the number of layers between the top of the skull and the microphone is increased, the effectiveness of the microphone system is reduced. Moreover, the helmet mounted ear-muffs of the communications system would be less effective at reducing external noise due to the ‘seal’ between the muff and the skin around the ear being compromised. This would require an increase in the volume of the communications speaker. Both of these factors increase the risk of damage to hearing and European standards recommend that “Protective clothing should be worn over any hearing protection and not underneath. Any attempt to wear ear-muffs or banded ear plugs over clothing will greatly reduce their effectiveness.” (BS EN 458, 1993, 6.5.2). This study was undertaken to measure the protection afforded by a fire hood manufactured with between 1 to 4 layers of material, to quantify the benefits of adding each layer to the final hood design. The study was designed to test the hypotheses that: .
the surface area of the head with a predicted burn injury will decrease with an in crease in the number of hood layers;
.
the greatest improvement will occur when doubling layers from 1-ply to 2-ply, with further additional layers offering a diminished return in protection.
Methods A prototype hood was designed to give a good fit around the face-mask of the new extended duration BA being introduced into service in the RN. The hood was designed in four variants with 1, 2, 3 or 4 layers (1– 4 ply) and was made from 50 per cent/50 per cent Kermel/FR Viscose (fabric weight 200 g m2). This material was chosen because is widely used commercially for similar end uses
and prototypes had been received favourably in an uncontrolled user evaluation. The level of protection against fire provided by the hoods was assessed using a flame manikin head form (Squire, 2000). The head incorporates 30 thermocouples distributed over its surface and it is engulfed in flame using 30 propane cup burners that produce a mean incident heat flux on the head of 53 kW m2 2, peaking at 85 kW m2 2. During the tests, head “skin” temperatures were recorded every second for sixty seconds from the time of the initial flame exposure. Heat flux incident upon the head was calculated from these data. Predictions of pain and tissue damage could be made from heat flux data using a model developed from human experiments (Stoll and Greene, 1959; Stoll and Chianta, 1971). Further details about the development of the manikin testing method, the method of use and the prediction of burn injury are published elsewhere (Squire, 2000). Predicted burn injuries were described as first (18), second (28), and third (38) degree burns. This classification describes the depth of damage to the skin. In simple terms: .
1 per cent degree burn is superficial reddening of the skin, which is painful but does not cause blistering;
.
2 per cent degree burn damages some of the skin layers with resultant blistering but does not cause scarring;
.
3 per cent is a full thickness burn, through the skin to the tissues below and results in scarring.
In each test, the hood was placed on the manikin head and engulfed in flame for specified periods of between one to ten seconds. The most likely duration of fuel explosion events is one to five seconds, most commonly being two seconds or less, and with ten seconds generally considered the maximum likely possible survival time in full flame exposure (for review see House, 1998). The hoods were challenged initially for four seconds so that the duration of subsequent challenges could be determined. If no burns were predicted after a four-second challenge, there was no need to conduct shorter duration tests and likewise, if severe burns were predicted, there was no requirement to conduct longer duration challenges. Four examples of the hoods were tested at each flame challenge to assess the variability of the test measures. For each test a new hood that had not been exposed to flame previously was used. Whilst the designated RN firefighting teams, like almost all civilian fire-fighters, wear a helmet and BA mask on the head, those providing the initial response to the fire on a ship may be wearing only the hood, or the hood and BA mask on their head. Accordingly, the hood should be tested when worn alone, with a BA mask, and with a BA mask & helmet. During a pilot study it was shown that the protective effect of the BA mask and helmet were consistent, irrespective of the hood type used or the flame duration, as might be expected. Thus the effect of wearing these items could be superimposed on the “hood alone” data to provide accurate predictions of burn
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injury without having to test (to destruction) a large number of expensive BA masks and helmets. To quantify the increase in head circumference when the hoods were donned the head circumference of 10 subjects was measured without, and with, each of the four hoods. The circumferences were taken at the level of the top of the ears and the forehead temples. Results Although 18 burn injuries were predicted they are not reported here. These type of injuries, although painful are not serious and heal quickly without permanent injury. All results quoted refer to the total predicted 28 and 38 injuries, which are more serious, rapidly debilitating, often cause permanent injury and are potentially fatal. Figure 1 shows the burn injury when the prototype hoods were challenged with flame for up to 10 seconds, with Figures 2 and 3 being the results incorporating the protective effects of the BA mask, and the BA mask & helmet respectively. From Figures 1– 3 it can be seen that the incidence of injury was reduced as the number of hood layers increased. It also appears as if the greatest improvement in protection occurred when increasing the hood layers from 1 to 2, with diminishing improvements in protection as subsequent layers were added. For example, after 4 seconds of flame engulfment the predicted burn injuries were 74 per cent, 28 per cent, 14 per cent and 13 per cent with 1-ply, 2ply, 3-ply and 4-ply hoods respectively. Similar results were seen when the effects of adding the BA mask and the helmet were added to the predictions, although the difference between the hoods was reduced as a smaller surface area of the head was exposed to flame. To visualise this more clearly the percentage reduction in predicted burn injury relative to that injury predicted when a 1-ply hood was worn is shown in Figure 4. Figure 4 uses the data for the
Figure 1. Mean percentage of head with a predicted 28 or 38 burn injuries when 1, 2, 3 or 4-ply firefighting hoods were worn (^ maximum and minimum values) ðn ¼ 4Þ
Firefighters’ hoods
115 Figure 2. Mean percentage of head with a predicted 28 or 38 burn injuries when 1, 2, 3 or 4-ply firefighting hoods and BA mask were worn (^maximum and minimum values) ðn ¼ 4Þ
four second flame challenges, the only common time period for which all hood types (1 to 4-ply) were tested. Figure 4 shows that the percentage surface area with a predicted burn injury when the head was exposed to flame for 4 seconds fell by 47 per cent when a 2-ply hood was used in preference to 1-ply, 60 per cent for a 3-ply, and 61 per cent for a 4-ply hood. When a BA mask, or BA mask plus helmet were worn these changes, although of lessor magnitude, were of similar proportion to that when the hood alone was tested. It should be noted that increasing 3-ply to 4-ply offered little reduction in burn injury. From Figures 1 – 3 it can be seen that for flame exposures longer than four seconds, the level of burn injury predicted for the 2, 3 and 4-ply hoods diverges, up to the maximum of 10 seconds i.e. there are differences between the hood
Figure 3. Mean percentage of head with a predicted 28 or 38 burn injuries when 1, 2, 3 or 4-ply firefighting hoods, BA mask and helmet were worn (^maximum and minimum values) ðn ¼ 4Þ
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Figure 4. Mean reduction in head surface area with a predicted burn injury when extra layers were added to a 1-ply hood, and exposed to flame for 4 seconds (^maximum and minimum values) ðn ¼ 4Þ
Figure 5. Mean reduction in head surface area with a predicted burn injury when extra layers were added to a 1-ply hood, and exposed to flame for 8 seconds (^maximum and minimum values) ðn ¼ 4Þ
types. Although, the 1-ply hood was not tested at 10 seconds, considering the data presented in Figures 1 and 3 it is reasonable to assume that the maximum level of burn injury with a 1-ply hood for flame exposures between 6–10 seconds would have been 80 per cent, or 60 per cent and 45 per cent with a BA mask or BA mask plus helmet, respectively. Using these assumptions, the reductions in head surface area with a predicted burn injury when 2, 3, and 4-ply hoods were tested can be calculated, these are shown in Figure 5. Again, when the hoods alone were tested, more than half the improvement of using multi-layered hoods over the 1-ply variant occurred using a 2-ply hood, with approximately two-thirds improvement with the 3-ply and full improvement with the 4-ply. Mean head-circumferences were increased: 1.1 cm, 1.8 cm, 2.2 & 2.7 cm (all SDs 0.7 cm) when the 1-ply, 2-ply, 3-ply and 4-ply hoods were worn respectively ðn ¼ 10Þ:
Conclusions As expected, the level of protection from fire afforded to the head increased as the number of layers of FR material in the hood was increased, supporting our first hypothesis. More importantly, the majority of the differences in the protection afforded the head, as related to the number of hood layers, occurred at the longer duration flame exposures. At eight seconds, the differences between the hoods were greater than at an exposure of four seconds although, even then, more than half the improvement in protection occurred using the 2-ply hood. Considering that the duration of most fuel explosions and flashovers may be less than 2 seconds (for review see House, 1998), albeit at heat fluxes 1.5 to 2 times greater than produced by the gas burners in the system used in this study, the level of protection provided at 4 seconds in this study may be the most important (i.e. twice the duration, half the heat flux, resulting in the same heat energy exposure ). In this case, the level of protection provided by the 2-ply hood was much greater than the 1-ply hood, with the 3-ply hood offering a much smaller increase in improvement over the 2-ply hood. The 4-ply hood offered no additional advantage. This would support our second hypothesis, for the flame events of the most likely duration. The data would support our second hypothesis, at least for exposures to which firefighters might reasonably be considered to be at risk. Of course, if there were no restrictions to the design of firefighting hoods, a 4-ply hood, which gives better protection in the extreme (and rare) longer duration events should be chosen. However, the likelihood of there being no other restrictions to the hood design seems remote. Cost must be assumed to have a bearing on all equipment, and multi-layered hoods cost more due to the requirement for extra material and the use of a more complex manufacturing process. For the RN, like many other organisations, there are also other considerations. Compatibility with the new firefighting helmet, and soon to be introduced communications system resulted in a conflicting requirement for as thin a hood as possible. The increases observed in head circumference when the hoods were worn were such that it is estimated that up to 36 per cent of the RN population would exceed the largest standard size produced by the manufacturers of the new firefighters’ helmet. The problem of special-fit helmets, or reduced numbers of personnel able to be firefighters, is minimised when a 2-layered hood is worn (a much cheaper solution than requiring manufacturers to provide special sized helmets). A RN firefighting trials and evaluation team assessed the effectiveness of the prototype communications helmet with the different hoods. The 2-ply hood was considered compatible, but the 4-ply hood was assessed as interfering to an unacceptable degree with the conduction microphone; these results are preliminary and unpublished and will not be investigated further until the communications system is fully developed. The findings in this study are important for the RN; they support the moves to use a 2-layered hood to increase the compatibility with the new
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firefighting helmet and communications system, whilst retaining a good level of protection. References House, J.R. (1998), Balancing the fire and flash protective clothing needs of Royal Navy personnel against the debilitating effects of heat strain. The Institute of Marine Engineers’ Fourth International Naval Engineering Conference and Exhibition, HMS Sultan 15-17 April 1998 Proceedings Part II, 21-29. EN 458. (1993). Hearing protectors – Recommendations for selection, use, care and maintenance – Guidance document (Paragraph 6.5.2). Squire, J.D. (2000), Development of the Research and Technology Group flammability manikin systems. Proceedings of the 1st European Conference on Personal Protective Equipment, Stockholm, Sweden May 7-10. Stoll, A.M. and Chianta, M.A. (1971), “Heat transfer through fabrics as related to thermal injury”, Transactions NewYork Academy of Sciences, pp. 649-70. Stoll, A.M. and Greene, L.C. (1959), “Relationship between pain and tissue damage due to thermal radiation”, Journal of Applied Physiology, 14 No. 3, pp. 373-82.
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Pressing performance of light-weight wool and wool blend fabrics
Performance of light-weight wool 119
G. Wang Fashion Institute, Dong Hua University, Shanghai Peoples Republic of China
Received April 2001 Accepted December 2001
R. Postle Department of Textile Technology, School of Materials Science and Technology, The University of New South Wales, Sydney, Australia
D.G. Phillips CSIRO Division of Textile and Fibre Technology, Geelong, Victoria, Australia, and
W. Zhang Fashion Institute, Dong Hua University, Shanghai Peoples Republic of China Keywords Fabric, Temperature, Wool Abstract The press performance of a range of wool and wool blend fabrics has been investigated with the aid of a temperature adjustable hand steam iron, a domestic ironing board and a thermocouple digital temperature display. It was found that for a press duration of 10 seconds, the fabric crease angle is reduced with the increasing press temperature. The sharpest reduction in crease angle was found in the temperature range of 808C to 1208C for all fabrics tested. At 1008C iron temperature, the fabric crease angle was reduced with increasing press duration until 20 seconds for wool fabrics and until 30 seconds for wool blend fabrics. The initial regain, or in other words, the relative humidity of the ambient atmosphere used to precondition the samples, has an important influence on the press performance. It was also found that the fabric crease recovery was greater for increasing ambient relative humidity. The fabric regain was greatly reduced during the first 10 seconds pressing time with further very slow reduction in fabric regain until 80 seconds pressing time. The regain in the upper layer of the fabric specimen was always lower than that in the lower layer.
Introduction Garment appearance is very important from the viewpoints of the garment manufacturer or tailor, the retailer and the ultimate consumer. Superior We gratefully acknowledge the financial assistance of the Australian government and Australian wool growers in the form of a research grant administered by IWS.
International Journal of Clothing Science and Technology, Vol. 14 No. 2, 2002, pp. 119-131. q MCB UP Limited, 0955-6222 DOI 10.1108/09556220210424224
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garment appearance is universally desirable and derives from the combination of style, suitable choice of fabrics, tailoring skill and successful pressing. Steam pressing is an important procedure which is extensively and repeatedly used in the garment industry, both during garment manufacture and in the after care processes of dry cleaning and laundering. Pressing represents the final opportunity to impart shape, flatness, creases and other desirable attributes to the garment. Many research workers have investigated the pressing conditions in order to optimise steam pressing (Kopke and Lindberg, 1966; Baird, 1968; Kalecki et al., 1974; Rosenblad-Wallin and Cednas, 1974; Pharo and Munden, 1978; Dhingra and Postle, 1980). In practice, however, the pressing temperature has been limited within a narrow range. Poor crease retention at the seams may occur after pressing and results in an undesirable blown’ appearance. Biglia et al. (1991) carried out industrial and laboratory trials to study the relationship between the garment appearance and measured fabric properties. They developed a simple measurement of fabric pressing performance indicated by the fabric crease angle. A low crease angle is a necessary but not sufficient condition for a good pressed seam appearance. It was concluded that crease angle can be used in combination with fabric formability as measured by the FAST set of instruments Ly et al. (1988) to give an assessment of garment appearance of light-weight fabrics after pressing. Le et al. (1995) studied the effects of decatising treatments at various temperatures and regains on the pressing performance of wool fabrics. The pressing performance is strongly affected by fabric regain and the level of set imparted during decatising treatments. It was proposed that the pressing performance of a wool fabric is comprised of two components, namely: temporary and permanent. The temporary component depends on the fabric regain during the last setting treatment and the permanent component depends on the level of permanent set imparted to the fabric by all previous treatments. The hand iron is also extensively used in garment manufacturing and particularly in domestic garment after-care. The advantage of using a hand iron to investigate fabric pressing performance is the flexibility in the sense of multiple choices of fabric pressing temperature. In the present work, the effects on the pressing performance of wool and wool blend fabrics of iron temperature, press duration, ambient relative humidity and the changes of fabric regain during pressing will be investigated for hand iron and domestic ironing board conditions. Experimental Pressing temperature control The hand iron used was a well known brand in China, viz. “Red Hart”. This is a temperature adjustable steam hand iron for which the steam was locked
throughout the present work i.e only dry heat (no steam was used in our experiments). The iron has a dial which can select six temperature ranges. At any one range, the temperature changes slowly within the range. With the aid of a digital temperature display comprising a thermocouple sensor, the temperature during pressing can be effectively controlled during the pressing for that part of the iron where contact with the fabric is made and the fabric crease is set. Table I shows the iron temperature in the fabric contact region of the iron during 1008C pressing and 1808C pressing.
Performance of light-weight wool 121
Fabrics tested In this investigation, a range of eight commercially available wool and wool blend fabrics and one polyester fabric were used. The characteristics of these fabrics are listed in Table II. Setting the fabric crease The hand steam iron and a domestic ironing board, together with the digital temperature display, were used to set the crease in the fabric. In order to avoid the uncertain influence from the ironing board, the specimen was carefully positioned with respect to the sensor of the digital temperature display and the iron. Figure 1 shows the relative positions of these items. Pressure was carefully applied by the weight of the iron itself. Tester et al. (1995)) found that the weft crease angle should be considered as more important for garment appearance. So, in this study, only weft specimens were used. Three specimens were cut from each fabric sample into 2 £ 6 cm size (warp £ weft) and preconditioned in the laboratory. Immediately before pressing, the fabric specimen was folded along the warp direction into 2 £ 3 cm size (warp £ folded weft). When the iron temperature was steady, the folded fabric specimen was placed in position and pressing with the iron was carried out by placing the iron on the fabric for the specified time after which the iron was removed. The fabric specimen was rapidly removed from the pressing position and cut parallel to the crease to 2 £ 1 cm size (warp £ folded weft). The creased fabric with two arms of 1 cm width was then available for crease angle measurement.
Press duration (s) Pressing temperature ranges (8C) Pressing temperature ranges (8C)
5
10
20
30
40
80
100 – 101
100 – 101
99 – 101
99 – 101
100 – 102
98 – 102
180 – 181
180 – 181
179 – 181
178 – 181
178 – 182
174 – 184
Table I. The pressing temperature ranges during 1008C and 1808C pressing
Table II. The characteristics of the fabrics tested 2W
3W
4 W/PE
5* WS
6* WS
7 W/PE
8 PE
9W
Per cent wool 70a 100 100 50b 100 100 60c 0d 100 187 211 145 147 160 169 171 187 248 Mass (g/m2) Construction Twill Twill Plain Plain Plain Plain Twill Jacquard Gaberdine Warp density (tex) 12:5 £ 2 18:5 £ 2 14:3 £ 2 14:3 £ 2 15:2 £ 2 17:5 £ 2 12:5 £ 2 11.1 17:5 £ 2 Weft density (tex) 12:5 £ 2 18:5 £ 2 14:3 £ 2 14:3 £ 2 15:2 £ 2 17:5 £ 2 12:5 £ 2 23.8 17:5 £ 2 Ends per 10 cm 385 345 238 253 253 230 330 630 420 Picks per 10 cm 305 300 198 214 222 202 260 358 220 Note: a – 30 per cent polyester, b – 50 per cent polyester, c – 40 per cent polyester, d – 100 per cent polyester; * – treated with Synthappret BAP for shrinkproofing.
1 W/PE
122
Fabric
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Ambient conditions Five different experiments were conducted. The first experiment investigated the effect of iron temperature on the fabric press performance. The actual ambient atmospheric conditions were 208C ^ 28C; 60 ^ 5 per cent r.h. during the preconditioning and processing of the fabric specimens. The second and third experiments investigated the effect of press duration on the fabric press performance. The ambient conditions were 208C, 65 per cent r.h. The fourth and fifth experiments investigated the effect of ambient relative humidity on the fabric press performance. Two levels of relative humidity were used during the preconditioning and during recovery after pressing, one relative humidity level was 65 per cent and the other level was 94 per cent.
Performance of light-weight wool 123
Fabric crease angle measurement The fabric crease angle was first measured one and a half hours after the pressing operation. The fabric crease angle was again measured by allowing 24 hours recovery after the pressing. The crease angle was measured according to IWTO Draft Test Method No. 42, (1992). Using the optical bench, two crease angles were obtained by measuring the crease angle at both ends of the crease for each fabric specimen. The mean of six measurements for three fabric specimens was evaluated. Results and discussion The effect of iron temperature on pressing performance In this experiment, the press duration was 10 seconds. The ambient condition was 208C ^ 28C; 60 ^ 5 per cent r.h. Table III gives the mean values of fabric crease angles measured one and a half hours after pressing using different iron temperatures. Table IVgives the mean values of fabric crease angle measured after 24 hours recovery. It can be seen that for all the fabrics tested, the crease angle decreases with increasing iron temperature, i.e. fabric crease setting becomes more effective as the iron temperature is raised. It should be noted that the crease angle decreases very slowly as the temperature increases from 408C to 808C. The crease angle
Figure 1. The placement of the iron, fabric specimen and sensor
124
Table III. Fabric crease angles measured one and a half hours after pressing at different iron temperatures
40 60 80 100 120 140 160 180
173 158 141 99 54 48 30 20
173 159 141 104 66 42 24 23
173 156 116 78 36 28 20 18
172 157 116 100 71 45 28 19
175 165 146 114 72 46 33 28
174 163 135 88 57 39 26 20
172 161 143 99 62 34 23 12
171 162 143 101 76 74 48 39
Press temp. (8C) Sample 1 W/PE Sample 2 W Sample 3 W Sample 4 W/PE Sample 5 WS Sample 6 WS Sample 7 W/PE Sample 8 PE
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40 60 80 100 120 140 160 180
177 168 160 125 74 48 47 28
177 169 163 128 86 62 42 41
178 166 152 107 57 51 35 35
176 165 159 118 85 61 37 27
178 173 161 143 102 76 53 50
176 171 160 124 91 63 44 39
178 167 158 123 80 53 32 20
175 165 149 107 77 77 54 45
Press temp. (8C) Sample 1 W/PE Sample 2 W Sample 3 W Sample 4 W/PE Sample 5 WS Sample 6 WS Sample 7 W/PE Sample 8 PE
Performance of light-weight wool 125
Table IV. Fabric crease angles measured allowing 24 hours recovery after pressing at different iron temperatures
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decreases sharply with increasing iron temperature in the region of 808C to 1208C. The rate of reduction in the crease angle is again relatively slow for increasing iron temperatures above 1208C. These results may be explained in terms of the segmental mobility of fibre molecules and the glass transition temperature for wool and polyester fibres. With increasing iron temperature, fibres absorb more heat from the iron. Therefore the segmental motion of fibre molecules becomes easier and thus results in the decrease of fibre stiffness. The sharpest decrease of crease angle in the region of 808C to 1208C may be related to the glass transition of wool and polyester fibres occurring in this range of temperature. Wortmann et al. (1984) found that the glass transition temperature of wool fibres depends on their water content or regain and that the relation between the glass transition temperature and the water content of wool can be described by the Fox equation. According to the present work, the mean moisture regain of wool fabrics is about 7 per cent and 6 per cent respectively measured after 5 and 10 seconds pressing at 1008C iron temperature. The corresponding glass transition temperatures can be calculated using Fox equation and they are 1098C and 1178C respectively. The glass transition temperature of polyester fibre is known to be in the region of 81– 1258C. The effect of press duration on the pressing performance The first experiment showed that the crease angle decreased most sharply in the region of 1008C to 1208C iron temperature. Therefore, iron temperatures 1008C and 1808C were chosen to study the effect of press duration on the pressing performance. Results for the fabric crease angles measured one and a half hours after pressing and that measured 24 hours after pressing are given in Figure 1 (a) and (b) respectively for 1008 C iron temperature. Figure 2 shows that at 1008C iron temperature, the crease angle decreases sharply with press duration until 20 seconds for wool fabrics and until 30 seconds for wool blend fabrics. However, for the polyester fabric, the crease angle decreases until 80
Figure 2. The effect of press duration on the pressing performance using an iron temperature of 1008C. (a) crease angle measured one and half hours after pressing; (b) crease angle measured 24 hours after pressing
seconds press duration time. Figure 3 shows a similar trend for 1808C iron temperature. From Figure 2, it can be seen that sufficient crease setting cannot be achieved for all pressing times using an iron temperature of 1008C. This may be the result of three factors. The first factor is that an iron temperature 1008C is not high enough to impart sufficient set to either wool or polyester. The second factor is that the mechanical pressure of the steam iron may be relatively low. The third factor relates to drying of the heated fabric, i.e. the fabric regain decreases after 10 seconds pressing so that the fabric does not reach the glass transition temperature at the reduced regain. Comparing Figure 3 with Figure 2, it can be seen that the fabric crease angle for 1808C iron temperature is always much lower than the corresponding value at 1008C iron temperature. In this experiment, it was found that when the press duration was longer than 20 seconds at 1808C iron temperature, some odour resulted from the pressing for the wool and wool blend fabrics. This indicates that 1808C temperature is too high to be used when pressing wool and wool blend fabrics without a wet pressing cloth, which would prevent or reduce fibre damage or degradation caused by heating.
Performance of light-weight wool 127
The effects of fabric initial regain and post-conditioning relative humidity Samples 3 W, 4 W/PE and 6 WS were preconditioned at two different levels of ambient relative humidity for at least 24 hours and the measured initial regains
Figure 3. The effect of press duration on the pressing performance using an iron temperature of 1808C. (a) crease angle measured one and half hours after pressing; (b) crease angle measured 24 hours after pressing
Sample
3W
4 W/PE
6 WS
65% relative humidity 94% relative humidity
11.6 16.1
6.3 7.9
11.2 15.6
Table V. Percentage fabric regain reached by samples after preconditioning at different levels of ambient relative humidity
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of the three fabrics are given in Table IV. It is readily seen that, as expected, these fabrics reached higher initial regains when preconditioned at 94 per cent relative humidity compared with the same fabrics preconditioned at standard (65 per cent) relative humidity. The fabric crease angles measured one and half hours after pressing and that measured 24 hours after pressing for the three fabrics at different initial regains are given in Table VI. It can be seen that fabric initial regain has a significant effect on the pressing performance of wool and wool blend fabrics for 1008C iron temperature. When these fabrics were preconditioned at high (94 per cent) relative humidity, viz. with high initial fabric regains, much lower crease angles were obtained, especially for 30 seconds of pressing duration. A similar trend is also found for pressing at 1808C iron temperature. These results are attributed to the effect of moisture on the glass transition temperature of wool fibres. According to the study of Wortmann et al. (1984), the glass transition temperature of wool fibres decreases with increasing fibre moisture content or regain. The effect of preconditioning ambient relative humidity on the crease recovery is also shown in Table VI. It can be seen that the ambient relative humidity has a significant effect on the level of recovery of pressed creases for the pure wool fabric and the wool fabric treated with Synthappret BAP: the higher is the relative humidity, the higher is the recovery and the crease angle and hence the poorer is the final seam or crease appearance. For the wool/polyester fabric, the recovery of crease angle is much lower than that of the wool fabric and the wool fabric treated with Synthappret BAP under high ambient relative humidity, especially for the pressing at 1008C iron temperature for 30 seconds and the pressing at 1808C iron temperature for 10 and 30 seconds. These results indicate that, if the fabric is preconditioned at 208C and 94 per cent r.h. and then pressed under such conditions as 1008C iron temperature for 30 seconds or 1808C iron temperature for 10 seconds, then lightweight wool/polyester fabrics can attain sufficient set and the durability of this set is remarkably good. The pure wool fabric treated with Synthappret BAP also showed significantly lower crease recovery than the normal untreated pure wool fabric. This result can be attributed to the effect of the synthetic resin applied during the Synthappret BAP treatment. The changes of fabric moisture regain during pressing The typical results of moisture regain changes of the upper layer fabric and the lower layer fabric during the pressing at 1008C iron temperature are graphically depicted in Figure 4. It can be seen that the moisture regain decreases very quickly for the upper layer fabric in the first 5 seconds. Thereafter, the upper layer of the fabrics continues to lose moisture at a relatively slow rate for the next 5 seconds. Then, the fabrics lose their moisture at a very slow rate for the rest of the pressing time to 80 seconds. For the lower
6 WS
4 W/PE
3W
15.2
11.2
7.9
6.3
16.1
11.6
Initial Sample regain (%) 10 30 10 30 10 30 10 30 10 30 10 30
Pressing time (sec.) 58 48 18 8 84 69 49 8 67 62 20 8
86 82 24 15 107 92 56 14 84 80 22 15
– – 128 105 – – 114 30 – – 131 94
At 1008C iron temperature One and half hr. After 24 hr at After 24 hr at after pressing 65% r.h. 94% r.h. 18 18 8 8 13 14 8 5 15 12 8 8
27 27 15 15 18 16 14 9 21 21 15 15
– – 105 108 – – 30 23 – – 94 90
At 1808C iron temperature One and half hr. After 24 hr at After 24 hr at after pressing 65% r.h. 94% r.h.
Performance of light-weight wool 129
Table VI. The effects of fabric initial regain and post-conditioning relative humidity on the fabric crease angle
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Figure 4. Moisture regain changes with pressing time at 1008C iron temperature
layer, the moisture regain decreases in a very similar way to that of the upper layer. However, the moisture regain in the lower layer is always higher than that in the upper layer. These results are consistent with the observations of Pharo and Munden (1978) during steam pressing where the steam temperature was not clearly given. However, the steam temperature can be assumed to be 1208C when an analysis was made of their earlier report on this related topic (Kalecki et al., 1974). Both the results of this present work and those of Pharo and Munden (1978) are consistent with the observations of Kopke and Lindberg (1966) in laboratory press experiments where steam temperature was 1208C and steamflow rate was 1 kg/cm2. When compared with the results obtained by Kopke and Lindberg (1966) at 1048C steam temperature, there is a significant difference for the first 5 seconds pressing time. For the steam pressing results of Kopke and Lindberg (1966), there was an increase of a maximum of 3 per cent in fabric moisture regain in the first 5 seconds, then followed by a gradual decrease in fabric moisture regain. The final regain after 60 seconds steam pressing at 1048C steam temperature was about 8 per cent while the final regains after 40 and 80 seconds iron pressing at 1008C iron temperature are respectively 4.5 per cent and 3.1 per cent (average of the upper and lower layers). Therefore, it can be considered that steam-heating has the advantage of delaying the drying process of pressing. From Figure 4, it can be seen that the initial regain of wool fabric (3 W) is slightly higher than that of washable wool fabric (6 WS). This can be attributed to the Synthappret BAP treatment where the resin may reduce the absorption of wool fibres.
Conclusion The effect of iron temperature on the pressing performance of wool and wool polyester fabrics can be related to the glass transition temperature of wool and polyester fibres. The fabric crease angle is much lower for the pressing at 1808C iron temperature compared to the pressing at 1008C iron temperature when press duration is 10 seconds. The press duration has a significant effect on the pressing performance of the fabrics tested, especially for pressing at 1008C iron temperature. The ambient relative humidity for preconditioning and post-conditioning fabrics also remarkably influences the pressing performance. The comparison between the results of the changes of fabric moisture regain observed for pressing at 1008C iron temperature in this present work and those obtained by Kopke and Lindberg (1966) for steam pressing at 1048C indicates that iron pressing causes a much more dramatic decrease of fabric moisture regain than steam pressing. References Baird, K. (1968), “Temperature and moisture regain of wool fabrics during steam pressing”, Textile Res. J., 38, pp. 670-4. Biglia, U., Roczniok, A.F. and Ly, N.G. (1991), “The prediction of garment appearance of wool fabric“, in, Proc. of Textile Objective Measurement and Automation in Garment Manufacturing, Bradford University, UK pp. 175-8. Dhingra, R.C. and Postle, R. (1980), “Some aspects of the tailorability of woven and knitted outwear fabrics”, Clothing Research J., 10 No. 6, p. 39. IWTO Draft Test Method No. 42, Crease Pressing Performance Test, IWTO Technical Committee, 1992. Kopke, V. and Lindberg, J. (1966), “Steam pressing of wool fabrics: the influence of temperature and moisture regain on the efficiency of pressing”, J. Text. Inst., 57, pp. 551-73. Kalecki, E.H., Pharo, J.A., Dorkin, C.M.C. and Munden, D.L. (1974), “Some factors affecting the degree of set achieved during steam pressing of all wool fabrics”, Clothing Research J., 2 No. 1, p. 11. Le, V.C., Biglia, U., Tester, D.H. and Sarlej, L.M. (1995), Proc. 9th Int. Wool Text. Res. Conf. Vol. V, 3, Biella, Italy. Ly, N.G., Tester, D.H., Buckenham, P., Roczniok, A.F., Brothers, M., Scaysbrook, F. and de Jong, S. Simple Instruments for Quality Control in a Tailoring Company, IWTO Tech, Cttee Meeting, Paris, December, 1988, Report No. 11 Pharo, J.A. and Munden, D.L. (1978), “An investigation of the performance of wool/polyester blend fabrics during steam pressing”, Clothing Research J., 8 No. 2, p. 59. Rosenblad-Wallin, E. and Cednas, M. (1974), “Pressing of seams and creases”, Clothing Research J., 2 No. 3, pp. 115-21. Tester, D., Roczniok, A., Minazio, P., Mello, P. and Fleiss, C. (1995), The pressing Performance of Wool Fabric, in Proc. 9th Int. Wool Text. Res. Conf. Vol. V, 20, Biella, Italy, 3-10 Wortmann, F.J., Rigby, B.J. and Phillips, D.G. (1984), “Glass transition temperature of wool as a function of regain”, Text. Res. J., 54 No. 6, pp. 6-8.
Performance of light-weight wool 131
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IJCST 14,2
Communication CAD/CAM adoption in US textile and apparel industries
132 Received March 2001 Revised March 2001 Accepted August 2001
He Yan Department of Textile Products Design and Marketing University of North Carolina at Greensboro, USA
Susan S. Fiorito Department of Textile and Consumer Sciences Florida State University, Tallahassee, USA Keywords CAD/CAM, Apparel, Management, Technology Abstract This study examines the determinants of CAD/CAM adoption in American textile and apparel industries. Theories of innovation were used to develop hypotheses relating market factors to manufacturers’ decisions to adopt CAD/CAM technologies. A variety of sources were used to develop the survey which was mailed to a national random sample of 500 textile and apparel manufacturers. The responses of 103 manufacturers from 30 different states were analyzed. Factor analysis was used to identify the dimensions of reasons for CAD/CAM adoption. Hypotheses were tested with logistic regression analysis procedures. The CAD/CAM adoption was found to be driven primarily by the market and affected by the business-unit size. In addition, labor considerations affected recent CAD/CAM adoption.
International Journal of Clothing Science and Technology, Vol. 14 No. 2, 2002, pp. 132-140. q MCB UP Limited, 0955-6222 DOI 10.1108/09556220210424233
Introduction In recent years, American textile and apparel industries have faced intense competition from foreign companies. Competitive dynamics in many segments of the textile and apparel industries are being transformed as a result of technological innovation. These innovations have set the foundation for a retailing strategy known to most as Quick Response (QR). With QR, retailers and manufacturers are working as partners to meet the consumers’ requirements. In order to produce the right products at the right price, in the right time and in the right place, future manufacturers must be faster and more flexible than their competitors to rapidly respond to consumer demands and adapt to current and future trends. (Dunlop and Weil, 1996). The textile and apparel industries are being forced to change at a very rapid rate, due in part to the ever quickening pace of the information age and the trends toward globalization. (DesMarteau et al., 2000). These industry changes have necessitated the adoption of information technology (IT) in the textile and apparel industries. To be successful and competitive to achieve efficiency and productivity in manufacturing, the textile and apparel industries must use the most advanced IT concepts and methods, including computer aided design (CAD), computer aided manufacturing (CAM) and computer integrated manufacturing (CIM).
IT holds considerable promise for delivering gains in efficiency and quality. But CAD/CAM technology has not diffused to a significant degree in the American textile and apparel industries (Collier and Collier, 1990). The purpose of this study is to examine the determinants of the adoption of CAD/CAM technology in the American textile and apparel industries. Innovation diffusion theory provides a developed conceptual framework and an empirical base applicable to the study of technology evaluation, adoption, and implementation (Fichman, 1992). Diffusion theory provides quantitative and qualitative tools for assessing diffusion of technology and the various factors that facilitate or hinder technology implementation (Rogers, 1983). Objectives The objectives of this study are as follows: (1) Determine how the external pressure exerted by the retailer alters the process of CAD/CAM adoption. The retailer’s external pressure shows up as reduced throughput time for product assembly, improved product quality and the need to meet standards on product delivery. (2) Determine how the manufacturing firm adjusts the process of CAD/CAM adoption based on internal pressures. Internal pressures include human resource factors, such as reducing support workers and supervisors, reducing labor content for garment assembly and attracting new workers and technicians. (3) Compare CAD/CAM adoption status in companies with different sales volumes. Hypotheses The following hypotheses will be tested: H1. CAD/CAM adoption will be positively related to the external pressure that the textile and apparel firms experience. H2. CAD/CAM adoption will be related to the internal pressure that the textile and apparel firms experience. H3. CAD/CAM adoption will be positively related to the size of the firms as measured by their sales volume. Methodology Participants This study was conducted using questionnaires designed to assess the CAD/CAM adoption practices and performances of U.S. textile and apparel firms, the demographic variations of the firms and Chief Information Officers (CIOs).
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The national list of survey recipients was obtained from National Registers of Apparel Manufacturers and users lists provided by CAD/CAM vendors. The respondents were contacted to establish data validity. Survey instrument The instruments used for the collection of data were questionnaires developed specifically for this study revising previous questionnaires based on the literature of textile and apparel firms and IT users (Dunlop and Weil, 1996; Mehlhoff and Sisler, 1989; Armstrong, 1995). The questionnaires were developed separately for CAD/CAM users and non-users, and explored various topics including demographics and CAD/CAM practices of the textile and apparel firms. Personal contact was made to the national sample of textile and apparel firms stratified by size to solicit participation in the survey. Five hundred questionnaires were mailed to those who agreed to participate. One hundred and three returned questionnaires were deemed useable, for a response rate of 20.6 per cent. Data analysis Factor analysis was used to identify dimensions of reasons for CAD/CAM adoption. Logistic regression was performed to test hypotheses 1, 2 and 3 which examined the relationships between the firms’ CAD/CAM adoption and the external and internal pressure factors, and company size. Results The results of our analysis will be illustrated through descriptive figures and tables. We will begin with an analysis of the respondents showing the distribution of CAD/CAM users and non-users. This will be followed by a brief description of the respondents’ companies by sales volume and number of employees. We will next offer an illustration indicating which and when the various segments of the textile and apparel industries adopted CAD/CAM technologies. Reasons for and against adoption of CAD/CAM are presented and ranked. One particular reason against CAD/CAM adoption, which is lack of information, is further analyzed and broken down into sources of information about CAD/CAM available to firms. Hypotheses one through three were tested using logistic regression analysis and follow the discussion for and against CAD/CAM adoption. The regression model included one factor for external pressure and another factor for internal pressure, which were obtained using principal component factor analysis. The CAD/CAM adoption distribution is illustrated in Figure 1. Slightly over one-third (34 per cent) of the respondents had already adopted CAD/CAM systems, while approximately two-thirds (64 per cent) have not adopted these
technologies. Slightly over one-fifth (24 per cent) indicated that they would adopt CAD/CAM in the future. The sales volume for the manufacturing firms is illustrated in Table I. The manufacturing firm profile by annual sales volume for the respondents of this study highlights the differences between users and non-users. Non-users of CAD/CAM tended to be smaller manufacturing firms with just over one-half (50.8 per cent) of the non-users with sales volumes less than $10 million. None of the non-users had a sales volume of over $50 million. On the other hand, a very small percentage of CAD/CAM users had a sales volume of less than $10 million and all the larger manufacturing firms with sales volume more than $50 million had adopted CAD/CAM technologies. The majority of respondents to this study sales volumes ranged from $10 to $50 million annually. The number of employees for the manufacturing firms is illustrated in Table II. The manufacturing firm profile by number of employees for the respondents of this study clearly shows several important factors. First, it illustrates that non-users of CAD/CAM tend to be smaller manufacturing firms with nearly 90 per cent of the non-users of CAD/CAM having 100 or fewer employees. Second, it shows that for the most part users of CAD/CAM tended to be larger with nearly 40 per cent of them having over 100 employees. Overall, the manufacturing firms profile for those who responded indicated
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Figure 1. CAD/CAM adoption distribution
Sales volume ($ million) , 10 10 – 50 . 50
Number of employees , 50 50 – 100 . 100
Non-user (per cent)
User (per cent)
Total (per cent)
33 (50.8) 32 (49.2) 0 (0)
3 (8.3) 28 (77.8) 5 (13.9)
36 (35.6) 60 (59.4) 5 (5)
Non-user (per cent)
User (per cent)
Total (per cent)
25 (38.4) 33 (50.8) 7 (10.8)
5 (13.9) 17 (47.2) 14 (38.9)
30 (29.7) 50 (49.5) 21 (20.8)
Table I. Company profile: sales volume
Table II. Company profile: employee number
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that the majority of firms were mid-sized with 49.5 per cent that had between 50 to 100 employees. Figure 2 illustrates the adoption trend of major apparel CAD/CAM systems by different segments of the industries from 1980 to 1997. The increasing rate has been quite stable for the Marker Making and Grading systems. However, the demand for the Fashion Design and Pattern Development System (PDS) has been rapidly increasing in the past few years. See Table III for the three most important reasons for CAD/CAM adoption which were: .
Improves first-pass product quality;
.
Improves ability to meet retailer standards on product delivery; and
.
Reduces throughput time for product assembly.
Figure 2. CAD/CAM adoption trend
Table III. Reasons for CAD/CAM adoption
Reasons (in rank order)
Mean (Std.)
Improves first-pass product quality Improves ability to meet retailer standards on product delivery Reduces throughput time for product assembly
2.14 (.93) 1.82 (1.16) 1.80 (1.13)
*Based on a scale of 1 to 3 where 0 ¼ not important; 1 ¼ somewhat important; 2 ¼ important; and 3 ¼ extremely important.
CAD/CAM adoption
Reasons against CAD/CAM adoption (Table IV) include: .
system cost;
.
lack of information;
.
lack of experts, and
.
training time.
137
Lack of information resulting in the non-adoption of CAD/CAM was investigated further. Figure 3 shows CAD/CAM information sources for nonusers. Among those firms who indicated that they will adopt CAD/CAM systems, 60 per cent of them get the knowledge about CAD/CAM systems directly from vendor. On the other hand, 17 per cent of the firms choosing not to adopt CAD/CAM systems know about the systems directly from vendor. Reasons The cost of the CAD/CAM system is too expensive Nobody in the company knows about CAD/CAM system It is hard to find persons who know how to operate CAD/CAM systems It takes too much time to train a person to learn CAD/CAM systems
Percentage 72.7 45.5 22.7 20.5
Table IV. Reasons against CAD/CAM adoption
Figure 3. CAD/CAM information sources
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Table V. Factor loadings in CAD/CAM adoption reasons
Factor 1 labor consideration
Reasons Meets retailer standards on product delivery Reduces WIP inventories Improves product quality Reduces assembly time Improves job satisfaction of workforce Reduces material handlers and support workers Reduces supervisors Attracts new workers and technicians Reduces labor content for garment assembly Reduces space for assemble operations Eigenvalue Per cent of variance Reliability (Cronbach’s alpha)
Factor 2 process improvement .8007 .7080 .6336 .6450 .6904
.6937 .7841 .6093 .8528 .8825 6.91 57.6 .89
1.10 9.1 .84
To identify dimensions of reasons for CAD/CAM adoption, principal component factor analysis with varimax rotation was performed on 12 Likert-type items. This resulted in two factors with eigenvalues greater than one (Table V). Factor 1 was labeled Labor Consideration, which was used as a proxy for internal pressure. Factor 2 was labeled Process Improvement, which was used as an indicator of external pressure. The reliability of each factor was calculated using Cronbach’s alpha, showing high reliability for each factor. The result of the logistic regression analysis is a model that is highly significant (Table VI). The external pressure factor, and sales volume have a positive effect on CAD/CAM adoption, while internal pressure was negatively related to CAD/CAM adoption. Thus, hypothesis 1, 2, and 3 were supported. Conclusion The external pressure factor, and sales volume were both positively related to CAD/CAM adoption. The internal pressure was negatively related to CAD/CAM adoption. Independent variable
Table VI. Results of logistic regression analysis dependent variable: CAD/CAM adopters vs non-adopters
Ln Sale volume ($) Internal pressure factor External pressure factor Model x 2 N * Significant at P , :05. ** Significant at P , :01. *** Significant at P , :001.
b
Standard error
.87*** 2 .22* .21* 31.10*** 81
.23 .10 .11
If CAD/CAM adoption is linked to the competitive pressure faced by adopting firms, one would expect a higher probability of adoption among those manufacturing firms facing the greatest degree of pressure from retailers to provide products on a rapid replenishment basis. The internal pressure factor was negatively related to CAD/CAM adoption. This result is difficult to interpret in light of possible bi-directional causal flows between these two variables. The apparel industry is labor intensive. Is it more difficult for companies experiencing higher internal pressure to adopt CAD/CAM, since it will lead to reducing the number of workers as well as supervisors? Alternatively, for the companies with high level of automation, the labor issue may not be that important. The statistical result could be caused by both situations operating in different firms. Generally, manufacturer’s attitudes toward CAD/CAM systems are positive. The expense of the systems appears to be the major reason against adoption. Modernization of manufacturing equipment and strategies is essential for manufacturing firms today. However, the price of modernization is high, so a balance must be reached (Figure 4). This balance is necessary for successful companies between enhancing technology to improve manufacturing performance and the price to achieve that performance (Cahill, 1992). It is suggested that CAD/CAM vendors need to put more effort into communicating with textile and apparel firms and developing more customized products especially for those small and medium size companies since they are the majority of the industry.
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Figure 4. Balance between performance and investment (Cahill, 1992)
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The findings from these analyses are also quite important to educators and students. As CAD/CAM adoption in the textile and apparel industries increase, educators must be prepared to give students opportunities to become trained in the effective use of hardware and software that will soon become the basic tools of the industry. In turn, textile and apparel firms will be able to respond more competitively to both the external and internal pressure of the business requirements. References Armstrong, C.P. (1995), Creating business value through information technology: the effects of the chief information officer and top management team characteristics. Unpublished doctoral dissertation, Florida State University, Tallahassee. Cahill, N. (1992), “How to build a global competitor OE plant”, Textile World, 142 No. 12, pp. 60-3. Collier, B.J. and Collier, J.R. (1990), “CAD/CAM in the textile and apparel industry”, Clothing and Textile Research Journal, 8 No. 3, pp. 7-13. Dunlop, J.T. and Weil, D. (1996), “Diffusion and performance of Modular production in the U.S. apparel industry”, Industrial Relations, 35 No. 93, pp. 334-55. DesMarteau, K., Little, T.J. and Istook, C. (2000), “Information technology trends drive dramatic industry change”, Bobbin, 41 No. 12, pp. 48-60. Fichman, R.G. (1992), Information Technology Diffusion: A Review of Empirical Research. Proceedings of the Thirteenth International Conference on Information Systems. Dallas, Texas. Mehlhoff, C.E. and Sisler, G. (1989), “Knowledge, commitment, and attitudes of home economics faculty toward computers”, Home Economics Research Journal, 17 No. 4, pp. 300-18. Rogers, E.M. (1983), Diffusion of innovations, Collier Macmillan Publishers, London. The National Register of Apparel Manufacturers-Men and Boys’. (1996), Marche Publishing, California. The National Register of Apparel Manufacturers-Women & Children’s. (1996), Marche Publishing, California. 1996-1997 Garment Manufacturers Index. (1996) Marche Publishing, California.
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Nerves for smart clothing – optical fibre sensors and their responses
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Xiaoming Tao Institute of Textiles and Clothing, The Hong Kong Polytechnic University Kowloon, Hong Kong Keywords Clothing, Fibre optics Abstract Deals with the optical responses of fibre Bragg grating (FBG) sensors under different modes of deformation. It derives both the polarisation states and reflection spectra of FBGs based on coupled mode equations by considering the deformation perturbations. It conducts numeric simulations, finds that the experimental results agree well with the simulated ones for normal germano-silicate FBGs under different individual modes of deformations.
1. Introduction Man has always been inspired to mimic nature in order to create their clothing materials like our skin. However, till date, most textiles and clothing are lifeless. Fibre optic sensors, which are capable of measuring temperature, strain/stress, gas, biological species, and smell are typical smart fibres that can be directly applied to textiles as the nerves. Fibre optic sensors (FOS) are lightweight, small and flexible. They are based on a single common technology that enables devices to be developed for sensing numerous physical perturbations of mechanical, acoustic, electric, magnetic and thermal nature. A number of sensors can be multiplexed along a single optical fibre using wavelength-, frequency-, time- and polarisationdivision techniques to form one-, two- or three-dimensional distributed sensing systems. They do not provide a conducting path through the structure and do not generate additional heat that could potentially damage the structure. They do not require electrical isolation from the structural material and do not generate electromagnetic interference; this could be a crucial advantage in some applications. Textile fabrics and composites integrated with optical fibre sensors have been used to monitor health conditions of major bridges and buildings. FOS have been integrated in the textiles for monitoring and controlling of parachutes. The first generation of wearable motherboards has been developed, The authors wish to thank Hong Kong Research Grants Council for supporting this work (Grant No. PolyU5112/98E). Technical assistance in preparing this paper from Dr. Yang D.X. and Mr. Zhang A.P is appreciated.
International Journal of Clothing Science and Technology, Vol. 14 No. 3/4, 2002, pp. 157-168. q MCB UP Limited, 0955-6222 DOI 10.1108/09556220210437130
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which has optic sensors integrated inside garments and is capable of detecting injury and health information of the wearer, and transmitting such information remotely to a hospital. FOSs can be classified into three broad categories, intensiometric and interferometric as well as fibre Bragg gratings (FBGs), according to the sensing scheme. Intensiometric sensors are simply based on the amount of light detected through the fibre. In its simplest form, a stoppage of transmission due to breakage of a fibre embedded in the structure indicates possible damage. Interferometric sensors have been developed for a range of high-sensitivity applications, such as acoustic sensors and magnetic field sensors, and are usually based on single-mode fibres. For example, Mach – Zender interferometer, is one of the most common configurations. An alternative interferometric sensor, more suitable for localized sensing, is based on interference between light reflected from two closely spaced surfaces, which form a short-gage-length Fabry-Perot (FP) type interferometer. The strain or stress applied on the gage inside the structure can be determined by measuring the reflected spectrum or reflected light signal from the FP cavity, which is a function of the distance between the two reflected surfaces. The disadvantage of such devices is difficult to perform absolute measurements, and hard to form a multiplexing sensor array along a single fibre length due to the large loss of the discontinuing structure of a FP cavity. The FBG consists of a modulation in the refractive index, n(z), along a short length (z) of the core in germania-doped silica fibre with a period of L, which is given by nðzÞ ¼ neff þ Dneff cos½ð2p=LÞz þ f0
ð1Þ
where neff is the linear refractive index for a guided mode in the fibre core, Dneff is the modulation amplitude of the refractive index and f0 is the initial phase of the grating. The inscription of permanent Bragg grating can be achieved in the core of an optical fibre by interference of two coherent ultraviolet (UV) light beams or masked side exposure of intensive UV light. The grating thus has a holographically induced refractive index modulation with a period L. When a broadband light source is coupled into the fibre, those components with wavelengths that satisfy the Bragg condition are strongly reflected, but all other components pass through the grating with negligible insertion loss and no change in signal. The central reflecting wavelength, referred as the Bragg wavelength (lB) of a fibre grating, is determined by the Bragg condition:
lB ¼ 2neff L
ð2Þ
The Bragg wavelength shifts due to the axial strain or temperature are well defined when the fibre sensors are under axial deformation either in a free state or embedded in a structure (Udd, 1995; Tao et al., 2000). However, in flexible
textile structures, the integrated FBG sensors are normally subject to complex Nerves for smart deformation, often involving tension, torsion, bending and lateral compression. clothing Hence fundamental questions arise as their optical responses to these various deformation modes and their underlining principles are largely unknown. In order to address this issue of unknown phenomena, this paper presents a systematic study of reflective spectra and polarisation behaviour of FBG which 159 are subject to various modes of deformation, i.e. tension, torsion and lateral compression. 2. Electric field in single mode fibre and FBG Light in fibre propagates in the form of modes. In mathematics, a mode in optic fibre is a solution of the Maxwell’s equations under the boundary conditions. The guided modes are electric and magnetic fields that maintain the same transverse distribution and polarisation at all distances along the fibre axis. Each mode travels along the axis of the fibre with a distinct propagation constant and group velocity, maintaining its transverse spatial distribution and its polarisation. There are two independent configurations of electric and magnetic vectors for each mode, corresponding to two states of polarisation. When the core diameter is small, only a single mode is permitted and the fibre is said to be a single-mode fibre. Fibres with large core diameters are multimode fibres. In a single-mode fibre, the weakly guiding approximation nco 2 ncl ! 1 is satisfied, where nco and ncl are the refractive indices of the core and the cladding, respectively. The fundamental mode is the hybrid mode HE11, which consists of two orthogonal modes HEx11 and HEy11 in accordance with their polarisation directions, so the electric fields in a single-mode fibre which is not under Bragg condition can be well represented as Eðx; y; z; tÞ ¼
2 X
cm ðzÞE m ðx; yÞexp½2iðvt 2 bm zÞ
ð3Þ
m¼1
where c1 and c2 denote the slowly varying amplitudes of the orthogonal HE11 modes, v, b1, b2, E1, and E2 are the angular frequency, the propagation constants of HE x11 ; and HE y11 ; the transverse spatial distribution of electric field HE x11 ; and the transverse spatial distribution of electric field HEy11 ; respectively, and E 1 ðx; yÞ ¼ F 0 ðrÞe x þ ði=b0 Þcos u½dF 0 ðrÞ=dre z
ð4Þ
E 2 ðx; yÞ ¼ F 0 ðrÞe y þ ði=b0 Þsin u½dF 0 ðrÞ=dre z
ð5Þ
where F0(r ) represent the 0th order Bessel functions J0 in the core, and modified Bessel functions K0 in the cladding, respectively, b0, ex, ey, and ez are the propagation constant of the mode in an ideal single-mode fibre, the unit vectors
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in x, y, and z direction, respectively. Figure 1 shows the calculated and measured reflective spectra of a FBG. The coupled mode theory is often used to describe the polarisation characteristics, or modes coupling in optical fibre, and the reflection spectra of FBG sensors. When the optical response of an optical fibreRR is analysed based on the coupled mode theory, the electric field is normalised as E nt †E*nt dxdy ¼ 1: Based on the perturbation approach, the slowly varying amplitudes cm are determined by the following coupled mode equations dc1 ðzÞ=dz ¼ i{k11 c1 ðzÞ þ k12 c2 ðzÞexp½ðb2 2 b1 Þz}
ð6Þ
dc2 ðzÞ=dz ¼ i{k21 c1 ðzÞexp½2ðb2 2 b1 Þz þ k22 c2 ðzÞ}
ð7Þ
where the subscript 1 and 2 denote the modes HEx11 and HEy11 ; respectively. The amplitude coupling coefficient from mode m to mode n is given by ZZ 2 knm ¼ ðk0 =2b0 Þ ð1~ij E m Þ†E*n dx dy; n; m ¼ 1; 2 ð8Þ where 1˜ij is the dielectric permittivity perturbation tensor, which may include the perturbation during the manufacturing of the fibre, fabrication of the grating as well as other external factors such as deformation, temperature, etc. An evolution velocity V is usually introduced to describe qualitatively the polarisation characteristics of a specific polarisation behaviour. V in a generalised Poincare´ sphere can be expressed by the coupled coefficients as77
Figure 1. Calculated and measured reflective spectra of FBG
jVj ¼ ½ðk11 2 k22 Þ2 þ 4k12 k21 1=2
ð9Þ Nerves for smart
clothing 2x ¼ argðk11 þ k12 2 k21 2 k22 Þ
ð10Þ
2c ¼ arctan½ðk11 2 k22 Þ=ð4k12 k21 Þ1=2 where 2x and 2c are the latitude and longitude of the generalised Poincare´ sphere, respectively.
3. Optical responses of FBGs under tension No significant polarisation signals can be observed for FBG sensors under tension. But an FBG sensor has good linear characteristics when it is applied to measure the axial strain by reflection spectra. From differentiating equation 2, the relative shift of the Bragg wavelength due to strain is given by DlB I X ›neff 1 X ›L ¼ ji þ ji neff i ›ji L i ›ji lB where ji is the applied strain field to the FBG sensor. According to photoelastic effect, the first term on the right side of equation (12) can be written as n2 X 1 X ›neff ji ¼ 2 eff pij ji neff i ›ji 2 i where pij is the strain-optic tensor. For a homogeneous isotropic medium, 3 2 p11 p12 p12 0 0 0 7 6 6 p12 p11 p12 0 0 0 7 7 6 7 6 6 p12 p12 p11 0 0 0 7 7 6 pij ¼ 6 7 0 7 0 0 p44 0 6 0 7 6 6 0 0 0 0 p44 0 7 7 6 5 4 0 0 0 0 0 p44 where p44 ¼ ðp11 2 p12 Þ=2: In the case of tension, the strain response arises due to both the change in fibre index due to photoelastic effect, and the physical elongation including the corresponding fractional change in grating pitch of the FBG. If a uniaxial longitudinal stress s2 is applied to the FBG sensor in the
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ji ¼ ½2vjz
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2 vjz
0
jz
0
0T
where the superscript T denotes the transpose of a matrix, jz ¼ sz =E is the longitudinal strain, E is the Young’s modulus and v is the Poisson’s ratio. Here we will only discuss the axisymmetric problem where the optic fibre is a thermal isotropic material with a constant expansion coefficient a. Equation (12) can be written in the same form
Dl n2 j2 n2 ¼ j1 1 2 þ a ðP 11 þ 2P 12 ÞDT þ hDT P 12 þ ðP 11 þ P 12 Þ 2 j1 2 l ¼ f 11 þ h* DT
ð11Þ
where the strain sensitivity factor is
n2 j2 f ¼12 P 12 þ ðP 11 þ P 12 Þ 2 j1
ð11:1Þ
and the temperature sensitivity factor is:
h* ¼ h þ
an 2 ðP 11 þ 2P 12 Þ 2
ð11:2Þ
The detailed discussions of the two sensitivity factors and their relations have been reported elsewhere (Tao et al., 2000) for free and embedded FBG sensors. They are the functions of thermal, optical and mechanical properties of the fibre as well as the strain ratio. 4. Optical responses under torsion The sensitivity of the Bragg wavelength shift of an FBG sensor under torsion is very small. However, the polarisation response to torsion is significant. The torsion introduces shearing stress in the cross section of the fibre. If the twisted length of a fibre is L, and the angle of twist is q ¼ tL; where t is the torsion ratio that is the angle of twist per unit length along the axis of the fibre, the matrix for the strain due to this torsion is
ji ¼ ½. 0 0 0 tx
2 ty
0T
ð12Þ
so that the matrix for DDi, perturbation in optical impermeability, is: DDi ¼ pij ji ¼ ½0
0
0 p44 tx
2 p44 ty
0T
ð13Þ
The relationship between the dielectric permittivity perturbation and the Nerves for smart optical impermeability perturbation can be expressed as: clothing 1~torsion
ij
¼ 2n4co DDij
ð14Þ
The induced circular birefringence in a single-mode optical fibre is given by: Bc ¼ nco tlðp11 2 p12 Þ=ð2pÞ
ð15Þ
The polarisation of pulse UV beam and asymmetric geometry associated with the side-exposure of UV light during the FBG fabrication process will induce linear birefringence. The peak birefringence of the FBG can be calculated from the expression Dn ¼
l jphaseðQ1 Þ 2 phaseðQ2 Þj 2pL
ð16Þ
where L is the length of the FBG, Q1 and Q2 are the eigenvalues of the corresponding Jones matrix det½T ðtÞT 21 ð0Þ 2 QI ¼ 0
ð17Þ
where T, t, and I are the Jones matrix, the time from the beginning of the UV exposure, and the identity matrix, respectively. The symbol det and the superscript 2 1 denote the determinant and the inverse of a matrix, respectively. Based on the birefringence, a permittivity perturbation tensor can be used to represent its polarisation behaviour 3 2 0 0 D1x 7 6 D1y 0 7 ð18Þ 1~UV ¼ 6 5 4 0 0 0 0 where De y 2 De x ¼ 2neff ·Dn: By considering the azimuth f of the faster or slow axis of the FBG sensor and the titled angle q, equation (25) becomes 0
1~UV ¼ T z T x 1~UV T Tx T Tz
ð19Þ
where Tz and Tx are the rotation matrix around z, x axis, respectively. In the case of an FBG sensor under torsion, both shear strain-induced circular birefringence and UV-induced linear birefringence are considered: 1~ij ¼ 1~torsion
0
ij
þ 1~UV
ð20Þ
The FBG sensors can be treated as the wave-plates. Apparently, when an FBG sensor is under torsion, these wave-plates will be rotated. This means the
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Figure 2. Polarisation measurement of singlemode fibre of FBG
Figure 3. Calculated (left) and measured (right) polarisation states of FBG under torsion
geometric parameter, the azimuth f, will be changed during the twisting of an optical fibre. In numeric simulations, the parameters of the FBG sensor were chosen to be the same as those used in the corresponding experiments. The torsion model under investigation is shown in Figure 2. Figure 3 shows the measured and calculated polarisation states of an FBG sensor under torsion. The simulated result coincides with the experimental result. The initial orientations do not appear to affect the shape of the output polarisation signals. However, the ellipticity of the input light will affect the output polarisation signals significantly. The position of the FBG can influence the output polarisation signals significantly. On one side, it will change the direction of the angular velocity vector of the FBG sensor, and on the other side, it will provide a different initial state of polarisation to the FBG segment.
Although both their directions vary along the equator in a generalised Poincare´ Nerves for smart sphere, their respective variation velocities are different. clothing 5. Optical responses under lateral compression In the case of optical fibres under lateral compression, linear birefringence will be induced based on the strain – optic relationship, as follows: 3 4nco f B1 ¼ ð1 þ vÞðp12 2 p11 Þ lEr0 In the case of lateral compression, the propagated fundamental mode HE11 perfectly degenerates into x- and y-polarised modes with different propagation constants. According to the photoelastic effect and the stress – strain relationship, the effective index changes of the two polarised modes can be expressed as: Dneffx ðx; y; zÞ ¼ 2
n3eff {ðp11 2 2vp12 Þsx ðx; y; zÞ þ ½ð1 2 vÞp12 2 vp11 sy ðx; y; zÞ} 2E ð21:1Þ
Dneffy ðx; y; zÞ ¼ 2
n3eff {ðp11 2 2vp12 Þsy ðx; y; zÞ þ ½ð1 2 vÞp12 2 vp11 sx ðx; y; zÞ} 2E ð21:2Þ
Using the stress-strain relationship and equation (12), the relative shifts of the Bragg wavelength of two polarised modes at any point of the FBG due to lateral compression are then obtained by: n2 DlBx ¼ 2 eff {ðp11 2 2vp12 Þsx ðx; y; zÞ þ ½ð1 2 vÞp12 2 vp11 sy ðx; y; zÞ} lB 2E 2 v½sx ðx; y; zÞ þ sy ðx; y; zÞ=E
ð22:1Þ
n2 DlBy ¼ 2 eff {ðp11 2 2vp12 Þsy ðx; y; zÞ þ ½ð1 2 vÞp12 2 vp11 sx ðx; y; zÞ} lB 2E 2 v½sx ðx; y; zÞ þ sy ðx; y; zÞ=E
ð22:2Þ
The spectrum split of the polarised modes at any point is then given by: n2 DlBy ðx; y; zÞ 2 DlBx ðx; y; zÞ ¼ 2 eff ð1 þ vÞðp11 2 p12 Þ½sy ðx; y; zÞ 2 sx ðx; y; zÞ lB 2E ð23Þ
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A more rigorous treatment has been proposed (Zhang et al., 2001) in a full vector formulation where the permittivity perturbation induced by the external force has been employed rather than the change in the effective refractive index. Hence, by using the coupled mode equations, the electric field in the FBG sensors was simulated. Experiments were carried out to investigate the spectrum responses of FBG under compression; the setup for this is shown in Figure 4. The experimental and simulation results for reflective spectra are presented in Figure 5. By adjusting the polarisation controller, the reflectivity of the two split peaks was changed. Figure 6 shows the peak split of the refractive spectra of FBG as a function of line compression force. Good agreements have been obtained between the simulated and experimental results up to 10 KN/m. 6. Conclusion This paper has dealt with the optical responses of FBG sensors under different modes of deformation. Both the polarisation states and reflection spectra of FBGs have been derived based on the coupled mode equations by considering the deformation perturbations. Numeric simulations have been conducted. Experimental results agree well with the simulated ones for normal germanosilicate FBGs under different individual modes of deformations, as summarized in Table I.
Figure 4. Experimental setup of FBG under compression
Figure 5. Calculated and measured reflective spectra of FBG under lateral compression
Nerves for smart clothing
167 Figure 6. Reflection peak split sensitivity a) experimental result; b) simulation result; c) approximation result
Mode of deformation Tension Torsion Lateral compression Pure bending
Optical response Deformation induced linear/circular Bragg wavelength shift birefringence B1 =Bc 1200 pm/millistrain, at wavelength 1550 nm , 10 pm, at torsion ratio 0.072 rad/mm 2.0 pm/N (parallel), 8.6 pm/N (perpendicular), with length 10 mm , 260 pm, at curvature 2.43 cm2 1
0 Bc ¼ 9:7 £ 1027 s; ½s ¼ rad=mm; at 1550 nm B1 ¼ 5:1 £ 1024 ; at 10 N/mm B1 ¼ 1:5 £ 1025 ; (1/rbent)2 ½rbent ¼ cm
References Buck, J.A. (1995), Fundamentals of Optical Fibers, John Wiley & Sons, New York. Du, W.C., Tao, X.M., Tam, H.Y., et al., (1998), “Fundamentals and applications of optical fiber Bragg grating sensors to textile structural composites”, Composite Structures, Vol. 42 No. 3, pp. 217-29. Erdogan, T. and Mizrahi, V. (1994), “Characterization of UV-induced birefringence in photosensitive Ge-doped silica optical fiber”, Journal of Optical Society of America B, Vol. 11 No. 10, pp. 2100-5. Gafsi, R. and El-Sherif, M.A. (2000), “Analysis of induced-birefringence effects on fiber Bragg gratings”, Optical Fiber Technology, Vol. 6 No. 3, pp. 299-323. Marcuse, D. (1991), Theory of Dielectric Optical Waveguides, Second Edition, Academic Press, Boston. Rao, Y.J. (1997), “In-fiber Bragg grating sensors”, Measurement Science and Technology, Vol. 8 No. 4, pp. 355-75.
Table I. Optical responses of FBGs under various deformation modes
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Tao, X.M. (2001), Smart Fibres, Fabrics, and Clothing, Woodhead Publishing Co., Cambridge, UK. Tao, X.M., Tang, L.Q., Du, W.C. and Choy, C.L. (2000), “Internal strain measurement by fiber Bragg grating sensors in textile composites”, Journal of Composite Science and Technology, Vol. 60 No. 5, pp. 657-69. Udd, E. (1995), Fiber Optic Smart Structures, John Wiley & Sons, New York. Ulrich, R. and Simon, A. (1979), “Polarisation optics of twisted single-mode fibers”, Applied Optics, Vol. 18 No. 13, pp. 2241-51. Zhang, A.P., Tao, X.M. and Tam, H.Y. (2000), “Prediction of polarisation behavior of twisted optical fibres containing Bragg grating sensors”, Journal of the Textile Institute, pp. 105-16 Part 3. Zhang, A.P., Guan, B.O., Tao, X.M. and Tam, H.Y. (2001), submitted to Optics Communication.
The current issue and full text archive of this journal is available at http://www.emeraldinsight.com/0955-6222.htm
Development of the system for qualitative prediction of garments appearance quality Jelka Gersˇak
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University of Maribor, Faculty of Mechanical Engineering, Department of Textiles, Institute of Textile and Garment Manufacture Processes, Maribor, Slovenia Keywords Garments, Predictive techniques Abstract The contribution presented here is the development of the system for qualitative prediction of garment appearance quality. The starting point for designing such a system is a qualitative evaluation of garment appearance quality, based on the study of relation of fabric mechanical properties and achieved quality level of garment appearance, as well as the definition of elements of a system for qualitative evaluation of garment appearance quality level, i.e. its fit.
1. Introduction Garment quality is not only defined through its aesthetic and functional properties, but also as mechanical and physiological of wear, e.g. the feeling of well being in wearing, its proper drape and fit – visual quality of form. Knowing and predicting the properties such as drape and fit, e.g. visual form of an article of clothing is equally important in engineering planning of the quality of new models – collections, as well as in introducing new technologies of manufacturing by measure, which makes possible production of articles by individual measures, following individual customer requirements in an industrial environment. Evaluation and prediction of garment appearance quality level, e.g. its visual form, is a complex area of investigation, especially if we take the idea of quality as a “philosophical notion”, to be defined “as a property” accepted and evaluated through senses (i.e. red, soft), through perception not usually expressed quantitatively (Gersˇak, 1996). Contrary to that, quality can also be defined as a positive or negative property that can properly determine garment. This means that in an objective evaluation of garment appearance quality (its visual form), expressed and seen as complete harmony of the fabric used, its drape and quality of processing, it is necessary to start from fabric mechanics, as fabric is a basic construction element of an article of clothing. The problem of fabric mechanics and objective evaluation of garment appearance quality is not only highly complex, but also undetermined properly
International Journal of Clothing Science and Technology, Vol. 14 No. 3/4, 2002, pp. 169-180. q MCB UP Limited, 0955-6222 DOI 10.1108/09556220210437149
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as yet. The reason for this is that today’s evaluations are based on descriptive estimations. Furthermore, they are visual and extremely subjective. For this reason it is not possible to predict in advance the quality level of garment produced or its appearance – garment form. The problem of objective evaluation of garment appearance quality level and comparable evaluation of garment fit is therefore still present. According to the above facts, and based on the study of fabric mechanics and its influence on garment appearance quality level, the directions for design of a system for qualitative prediction of garment appearance quality and its prediction are presented in the frame of this paper. 2. Relationship between fabric mechanics and quality of the form – garment appearance While constructing high-quality garments, such as those that have to satisfy the requirements of individuality, e.g. in fulfilling high standards of comfort in wearing, it is necessary to pay special attention to obtain high-quality appearance (garment form), as well as to fit the garment to the anatomic part of the human body in question. The last two influential factors are directly linked to the investigations of fabric mechanics, meaning its ability to be processed from two-dimensional cutting patterns to a three-dimensional form of an article of clothing. These problems are especially present in manufacturing outer garment, such as jackets and the like, which utilize different shapes of cutting parts, with straight and curved contours, and where various materials are used in manufacture, such as interlinens, shoulder and other pads, meaning it is extremely difficult to obtain proper form and appearance of the article of clothing in question (Gersˇak, 1998). It is known that the form signifies the conferment of a particular shape during tailoring. To do this it is necessary to force an essentially twodimensional fabric to take on three-dimensional shape (Bona, 1994). The deformation in the zone between the shoulder and the neck, as well as the formation of a double curvature region at the top of the sleeve, where it joins the shoulder, are complex steps. In order to obtain these complex curvatures in a jacket in such a way that they remain well rounded and smooth (without wrinkles), different tailoring production techniques can be used. Bona (1994), Mahar et al. (1983), Postle et al. (1983) and Lindberg et al. (1960) dealt with the problem of formability and technique, known as overfeeding, with which it is possible to provide fullness in the structure and/or curvature in the direction of the seam. The mechanism of overfeeding was studied by Mahar et al. (1983) and Postle et al. (1983), who defined overfeeding, including those concerning deformation induces in the fabric plane. Also Bona (1994) and Lindberg et al. (1960) studied the relationship between formability and overfeeding. He stated that, as well as by fabric properties, the maximum level
of overfeed is also conditioned by the direction of sewing: warp to warp, weft to weft, on the bias. Bona (1994) stated that all these studies clearly indicate the possibility to adapt the making-up technique to the properties of the fabrics: or else, inversely, to establish limits of acceptability for the later, i.e. in practice a certain limit-level for overfeeding. As from the point of view of end use, regarding patterns and diversity of fabrics, as well as specific requirements of various sewing techniques (sewing technique, e.g. various ways of feeding individual layers of cutting patterns, has a considerable impact on the 3D shape of the article of clothing), and the requirement for smaller series, sewing techniques cannot be adapted to fabric properties, it is necessary to define minimum criteria for the parameters of individual fabric mechanical properties, e.g. the relation between the parameters of fabric mechanical properties and the degree of appearance quality (visual shape of the garment). Comprehensive investigation has been done in this area, too. Of special interest are the investigations done in the areas of performance in clothing and clothing manufacture (Kawabata and Niwa, 1989), tailoring process control (Kawabata et al., 1992), development of high quality apparel fabrics (Kawabata et al., 1997) and the ideal fabric project, as ideal fabric can be defined using three criteria: hand – T.H.V., suit appearance – TAV (three basic components of tailoring: formability, elastic potential and drape) and mechanical comfort. These investigations have yielded some interesting results and some prototypes of garments have been manufactured from the ideal fabrics described, but the problem of defining high quality garment appearance (garment form) is still present. It should be kept in mind that European customer has rather high criteria in evaluating the quality of appearance – visual form of the garment, as well as the fact that standards in the manufacture of high-quality, elegant, small-series articles for the customers of highest requirements are constantly rising. Individual wishes and demands of customers will certainly come soon into focus and “garment by measure” will soon a become predominant trend. The economy of the whole textile and garment industry will depend on the fact whether each individual step or manufacturing phase functions in an optimal way. It means that the changes in managing the link of supply and logistics will have to stress more fabric quality, e.g. fabric manufacturer will have to declare fabric quality adequate for high-quality garment, meaning appearance quality or visual form of the garment in question. Having in mind the complexity of obtaining high-quality appearance (garment form), associated with the ability to shape the garment properly through overfeeding in manufacturing the required 3D forms in the area of sewing shoulders and sleeves, as well as fabric drape and fit of the article of clothing, it is necessary to define clearly fabric mechanics, e.g. the parameters of fabric mechanic properties from the point of view of garment construction.
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Analyzing construction of outer garment, or its structure, it can be seen, that fabric properties in the direction of the warp are important in obtaining proper shape, i.e. the form of a jacket, as most seams run in that direction. The quality of the seam produced depends upon bending and shear rigidity, formability of the fabric and its elongation. In case of imperfect mechanical properties, the fabric is prone to shear deformation in the area of the seam, whereas the elongation and yield are reflected in the seam itself. This deformation can be seen as seam puckering and/or floating seam, and is a result of interaction of shear and bending rigidity and fabric elongation in the area of the seam (Gersˇak, 1997; 1998a, b). Besides fabric formability and elongation, shear properties, such as shear rigidity, shear hysteresis and bending rigidity are, due to specific construction requirements, very much important in order to obtain proper 3D shape in the areas of shoulder and sleeve seams, breast part and gussets on the rear part of the jacket. Fabric should have required dimensional stability, meaning shrink relaxation and hygral expansion should be properly low, as high shrink relaxation can result in sleeve creasing of the shoulder area during ironing, while high hygral expansion tends to impact detrimentally the appearance of the seam (seam puckering), and have adverse influence on the form of the article of clothing as well (Gersˇak, 1998; 2001). It can be concluded that there is a strong link between fabric mechanics and its behavior in a garment manufactured from it, e.g. garment appearance quality. As in most cases the impact is exerted by the interaction of a number of parameters defining mechanical properties, as well as by garment construction, it is not possible to predict precisely the degree of garment appearance quality on the basis of theoretical models and laws of fabric mechanics. It can only be done indirectly, establishing a correlation between fabric mechanics, e.g. particular mechanical properties, and the degree of appearance quality – form of the garment manufactured. 3. Definition of the model for qualitative evaluation of garment appearance quality Starting points for qualitative evaluation of garment appearance quality are the study of the influence of fabric mechanical properties on the assurance of garment appearance quality level, as well as definition of the elements for qualitative evaluation of the quality grade of garment appearance, i.e. garment fit. To achieve these goals, extensive theoretical and experimental research work has been done, enabling us to develop the system for qualitative evaluation of garment quality, based on analytical methods and results of the experimental work. In order to achieve these goals, set on the basis of the
problem presented above, the investigations are based on following hypotheses .
Fabric as a building element of an article of clothing has non-linear mechanical properties, defined by mechanical parameters.
.
Non-linear mechanical properties of fabrics in the area of lower loading influence the fabric drape in the garment produced, which is a starting point for the study of the quality grade of a garment and its fit.
The investigation of fabric mechanics and the development of the system for qualitative prediction of garment quality are subdivided into three parts. The first part presents the definition of the model for quantitative evaluation of garment appearance quality and the definition of the elements of the system for quantitative evaluation of garment appearance quality. The second part of the investigation is concerned with studying the influence of particular mechanical properties of the fabrics used on the grade of garment appearance quality. The influence of the parameters of particular mechanical properties on the quality grade of garment appearance and its fit is investigated for this purpose. In the frame of the third part, the system for qualitative evaluation of garment appearance quality, as well as its prediction, based on knowledge based systems and fuzzy logic, are designed, starting from the influence of particular mechanical parameters of the fabrics analyzed on garment appearance grade. The structure of the system for qualitative prediction of garment appearance is shown in Figure 1. 3.1 Criteria for qualitative evaluation of garment appearance quality As the evaluation of garment appearance quality can be done on the basis of the visual appearance of the garment form, reflected as 3D behavior of the fabric built-in, the model for qualitative evaluation of garment appearance quality is constructed on defining the following: .
aesthetic appearance – garment drape,
.
required form – 3D shape of the garment, and
.
quality of the fit.
If constructing the model of objective evaluation of appearance quality – garment visual form, the method of visual evaluation of the degree of garment appearance quality is used, based on systematically defined criteria for individual evaluations and parameters of fabric mechanical properties obtained. Appropriate control system was defined to ensure efficiency of the evaluation of the degree of garment appearance quality, based on determining influential elements of qualitative evaluation of appearance – garment visual form. Each element selected was analyzed in detail using predetermined
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Figure 1. The structure of the system for qualitative prediction of garment appearance quality
criteria for individual evaluation of appearance quality, and differences in grades were also presented graphically. 3.2 Elements for qualitative evaluation of garment appearance quality According to the criteria defined, the elements for qualitative evaluation of garment quality are divided into two groups: .
elements, determining the quality of a visual appearance, i.e. garment fit, which are directly linked with mechanical and physical properties of the fabrics used, and
.
elements, determining the quality of visual appearance as a consequence of quality of garment manufacture.
The elements, determining the quality of a visual appearance, i.e. garment fit, Figure 2, defined on the basis of the evaluation of quality of garment fit, are drape and assurance of 3D shape of the garment (fall of the front/back part and sleeve, shape of shoulders and sleeves) and visual appearance of the quality of seems produced, such as seam puckering, seam flotation, shear-deformed seam, etc. Among the elements determining the quality of a visual appearance as a consequence of quality garment manufacture, are pattern adjustment, symmetry of seems produced, quality of pocket, lapel, etc. Regarding the quality achieved, estimation marks from 1 to 5 are defined for the above elements, where 1 means excellent (cannot be any better), 2 is good, 3
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Figure 2. Criteria for qualitative evaluation of garment appearance quality
satisfactory (minor faults that can be detected by an expert), 4 below average and 5 poor. Furthermore, the study on the influence of particular parameters of mechanical properties of the fabrics used on quality grade of garment appearance has been carried out, based on precisely defined elements of garment appearance quality. Special attention has been given to the study of assurance of the form and formability, as well as to the relationship between the parameters of fabric mechanical properties and appearance, e.g. fit of the garment produced and appearance quality of the garment in the areas of straight and curved contours of seam constituent components. 4. Investigation of the impact of fabric mechanical property parameters on the degree of garment appearance quality The degree of appearance of the garment manufactured was estimated by implementing theoretical basis of relation between fabric mechanics and appearance quality – garment form. Mechanical and physical properties were evaluated for all the fabrics analyzed, using the KES-FB measuring system, while dimensional stability was assessed employing the FAST-4 testing method.
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Relation between individual parameters of mechanical and physical properties of the fabrics used and the degree of appearance quality (garment form) was established on the basis of the results obtained for mechanical properties of the fabric analyzed and the degree of appearance quality (visual form of the articles manufactured) achieved. The analysis of the relationship between the extensibility of the fabrics analyzed and appearance quality (garment form) achieved indicate that high warp-wise extension EMT has a detrimental influence on garment overfeeding (creating fullness), Figure 3, as well as on its softness and formability. Formability rises with elongation, which is reflected in unaesthetic garment drape. Contrary to this, low elongation in the direction of seam contour results in seam puckering. Sewing thread, as a linking element, causes, due to its bulk and pressure, a compressional strain in the seam area of the fabric. Deformation thus created is manifested as pushing the warp or weft threads away, i.e. seam puckering due to pushing the threads away, as seen in Figure 4. If the fabric in question exhibits simultaneously low bending, B, and shear, G, rigidity, coupled with low shear hysteresis, 2GH5, it cannot properly adapt to the deformation in the area of the seam. It is reflected as more or less puckered seam. Garment appearance quality is also affected by the relation between fabric extension in the direction of the warp and weft a ða ¼ EM2=EMT1Þ; which is, for fabrics used for ladies wear around 1. Higher or lower values than this can result in seam puckering and cause poor behavior of contours of different curvature in ironing. This, in consequence, means low quality of 3D shape (garment form). It was also established that low values of shear rigidity, G, and shear hysteresis 2HG5 directly impact garment appearance. It happens through so called “seam weaviness”, as well as through poor garment drape, which is especially pronounced with sleeves. The seam, as a linking element, due to the mass of sewing thread in stitches, causes shear deformation of the fabric in its vicinity. This deformation can, in case of higher extension of the fabric weftwise, or perpendicular to it, cause fabric elongation in the area of the seam, manifested as seam puckering and/or floating seam, Figure 5. It is also necessary to emphasize the impact of some other parameters on garment fit, such as bending rigidity (G) and bending hysteresis 2HB1 and 2HB2, which release the energy captured by bending deformation, and have a considerable impact on garment drape and on the quality of the seam produced as well. Fabrics with lower bending rigidity (B) ensure better fabric flexibility in the garment manufactured. However, too low a value has a detrimental influence on the visual appearance of the seam, as the fabric cannot reach a satisfactory level of fullness and cannot compensate the deformation occurring in the area of the seam.
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Figure 3. Visual form of unaesthetic garment drape
Higher bending rigidity values impact formability and enhance the resistance of the fabric to wrinkling/creasing/bulking. It should be noted that, it is advisable to consider the impact of the parameters of bending properties, i.e. bending rigidity and bending hysteresis, in relation to stretching and bending properties, since parameters such as extension (EMT1 and EMT2, EM2/EMT1), shear rigidity (G) and shear hysteresis (2HG5) impact considerably final visual garment appearance.
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Figure 4. Seam puckering
Interesting conclusions can also be reached by analyzing dimensional changes of the articles of clothing tested in ironing, both in positive and in negative changes of dimension. The analysis of the results obtained indicate that fabric behavior in the area of the seam is affected by the seam contour shape, the ability of the fabric to take a new form required. This is defined by bending and shear properties and their hysteresis values, elongation and dimensional stability, i.e. relaxation shrinkage and stretching in wet state. Due to poor formability, fabrics often cannot take the required form and thus stretch or shrink in ironing. These changes are more clearly pronounced in fabrics with low relaxation shrinkage and high stretching in wet, and vice versa. Key elements for designing a knowledge basis are obtained understanding of the impact fabric mechanical properties have on the degree of garment appearance quality, i.e. through the results of evaluating the degree of garment appearance quality and mechanical and physical properties of the fabrics analyzed. They are used as input units in designing the knowledge basis, which will, as a result enable us to predict the degree of garment appearance quality and help engineering high-quality garment. 5. Conclusion Knowledge and definition of the relation between fabric mechanics, based on mechanical parameters, and quality grade of garment appearance is of essential importance for engineered planning of required garment quality.
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Figure 5. Shear deformation of the fabric and floating seam
Definition of the common criteria for objective evaluation of the garment appearance quality, which serves as a starting point for knowledge base design, i.e. for the design of a system for qualitative prediction of garment quality, will enable the comparison of a quality grade of the garment produced and its fit, for different models and types of garments. The information obtained on fabric behavior in the article of clothing manufactured, i.e. on ensuring the required degree of appearance quality – visual form of the garment manufactured, will also be a sound basis for engineering prediction of fabric mechanical and physical properties, as related to the required properties of high-quality garment.
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References Bona, M. (1994), Textile Quality, Physical methods of product and process control. Textilia, Istituto per la Tradizione e la Technologia Tessile, Biella. Gersˇak, J. (1996), Material Quality requirements – Expense or saving (Kakovostne zahteve materiala – strosˇek ali prihranek). Proceedings of the 3rd symposium Clothing Engineering, Faculty of Mechanical Engineering, Maribor, pp. 37-46. Gersˇak, J. (1997), Ursache der Gewebe- und Sakkodeformation im Bereich der Ru¨ckenmittelnaht: fachliche Gutachtung [ fu¨r MURA, European Fashion Design, Murska Sobota ]. Faculty of Mechanical Engineering, Maribor. Gersˇak, J. (1998a), Does garment manufacture industry know the material? (Pozna oblacˇilna industrija material?) Proceedings of the 4th symposium Clothing Engineering, Faculty of Mechanical Engineering, Maribor, pp. 38-44. Gersˇak, J. (1998b), Expert opinion of reason of low quality jacket appearance and floating seam. Faculty of Mechanical Engineering, Maribor. Gersˇak, J. (2001), Expert opinion on processing ability of fabrics and sources of their deformations in seam areas. Faculty of Mechanical Engineering, Maribor. Kawabata, S. and Niwa, M. (1989), “Fabric performance in clothing and clothing manufacture”, J. Textile Institute, Vol. 80 No. 1, pp. 19-50. Kawabata, S., Ito, K. and Niwa, M. (1992), “Tailoring process control”, J. Textile Institute, Vol. 83 No. 3, pp. 361-74. Kawabata, S., Niwa, M., Kurihara, S., Yamashita, Y., Inamura, A. (1997), Development of high quality apparel fabrics by means of Objective Measurement. 78th World Conference of The Textile Institute, Thessaloniki. Lindberg, J., Waessterberg, L. and Svenson, R. (1960), “Wool fabrics as garment constructions materials”, J. Textile Institute, pp. T1-T465. Mahar, T.J., Dhingra, R.C. and Postle, R. (1983), The investigation and objective measurement of fabric mechanical and physical properties relevant to tailoring. Proceedings of the 2nd Symposium, Parkville, ed. J. Text. Mach. Soc. Japan, Osaka. Postle, R., Kawabata, S. and Niwa, M. (1983), Wool fabric and clothing objective measurement technology. Proceedings of the 7th International Wool. Textile Research Conference, Tokyo.
The current issue and full text archive of this journal is available at http://www.emeraldinsight.com/0955-6222.htm
From fabric hand to thermal comfort: the evolving role of objective measurements in explaining human comfort response to textiles
From fabric hand to thermal comfort 181
Roger L. Barker Center for Research on Textile Protection and Comfort, North Carolina State University College of Textiles, Raleigh, NC, USA Keywords Textiles, Physical properties Abstract This paper traces the evolution of objective measurement of textile hand and comfort from Pierce through modern methodology and approaches. Special emphasis is given to discuss the contribution of the Kawabata Evaluation System (KES) towards advancing the state of objective measurement. Laboratory case studies are used to show how data generated by the KES and other instruments can be integrated into a comprehensive approach that attempts to explain human comfort response to garment wear in terms of fabric mechanical, surface and heat and moisture transfer properties.
Introduction Scientifically based approaches to objective measurement of textile hand and comfort must be based on an understanding of the complexity of human sensory response to clothing materials. Pontrelli (1990) introduced the concept of “Comfort’s Gestalt” to discuss the various stimuli which result in comfort or discomfort (Table I). Therefore, comfort is not only a function of the physical properties of materials and clothing variables, but must be interpreted within the complete context of human physiological and psychological response. Human expectations, or stored modifiers, that filter or influence our judgement about comfort based on personal experiences must be also considered. Pontrelli’s analysis emphatically defines the complexity of factors influencing human comfort response and, in doing so, underscores the challenges embodied in attempts to measure properties of fabrics, or garments, that correlate with the perception of hand and comfort. Objective measurement of fabric hand Recognition of the importance of primary sensory factors to an overall evaluation of fabric hand preference is a fundamental idea that has been shared
International Journal of Clothing Science and Technology, Vol. 14 No. 3/4, 2002, pp. 181-200. q MCB UP Limited, 0955-6222 DOI 10.1108/09556220210437158
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Physical stimuli
Psycho-physiological factors
Level of physical activity Fabric/garment properties Fiber content/fabric constructions Moisture and heat transport Air permeability Fit/stretch/tactility
State of being End-use and occasion of wear Style-fashion Fit, familiarity
Environmental factors Air temperature, humidity, etc. Table I. “Gestalt” of comfort
Stored modifiers Past experiences Bias Expectations Life style
Source: Pontrelli (1990)
by many researchers, including the classic work by Pierce (1930), Hoffman and Beste (1951), Howorth and Oliver (1958) and Lundgren (1969). Pierce identified a number of simply measured fabric properties that correlate with judging the feel or handle of a material, including sensations related to stiffness or hardness (Table II). Pierce’s landmark research provided foundation for simple and useful measurement of handle predicting fabric properties that are widely utilized in textile measurement to this day, most notably the measurement of fabric bending length. Other researchers including Dawes and Owen (1971a, b), Winakor et al. (1980), Brand (1964), Vaughn (1975), and Matsuo et al. (1971) have contributed much to the science of objective measurement of fabric hand. The most widely known and well-developed modern system available for standardized evaluation of fabric hand is the Kawabata System of Evaluation (KES) (Kawabata and Niwa, 1980). The basic of Kawabata’s methodology is the assumption that fabric hand is derived from a combination of primary sensory factors such as softness, stiffness, or roughness. A second assumption in Kawabata’s approach is the notion that the ultimate judgment of hand of a fabric is biased according to the specific apparel end use. Consequently, the set of primary sensory components that is appropriate and the weight of individual sensory factors in the overall hand evaluation are critically determined by end use function. This means that the set of primary factors for
Table II. Fabric properties associated with stiffness and hardness (Pierce, 1930)
Bending length, C Flexural rigidity, G Thickness, d Density, p Hardness, H Bending modulus, q Compression modulus, h Extensibility, q
fabrics that are intended for a particular class of garments, such as men’s From fabric hand suiting, is specific and unique to that class of fabrics. It may not be inclusive of to thermal factors controlling the overall hand evaluation of some other type of clothing comfort such as ladies dress material, for example. Finally, the system of instruments developed by Kawabata for the objective evaluation of hand joins numerous other methodologies that seek to predict the sensory components of hand from 183 fabric properties measured in laboratories. The unique feature of Kawabata’s devices, however, lies in their ability to measure fabric mechanical properties at small strains with high sensitivity. The instruments provide unprecedented capability to isolate the contribution of individual fabric properties and to define the role played by tensile, bending, compression, shear and surface properties on tactile sensations. This analytical power, combined with the capability to characterize energy loss in mechanical deformation and recovery processes, provides an unparalleled tool for use in fabric hand analysis. Our experience in using the KES confirmed that translations between subjective hand and fabric properties, measured using the KES, must be customized for specific categories of woven or knitted fabrics (Table III). Research studies, conducted at North Carolina State University (NCSU), show that, for well defined sets of fabrics, human perception of hand can be reliably predicted using simple linear regression models that incorporate as few as two KES measurements of fabric properties (Vohs et al., 1985; Barker and Luckey, 1989; Chen et al., 1992). These hand translation models typically incorporate bulk mechanical properties (tensile, bending, or compression) and a fabric surface property measurement (surface friction or roughness). Measuring clothing comfort Beyond fabric hand, clothing comfort has two main aspects that combine to create a subjective perception of satisfactory performance. These are thermophysiological and sensorial comfort. The first relates to the way
Sheeting (Vohs et al., 1985) Hand ¼ 2:51 þ 4:34 log WT 2 1:15 log MMD þ 1:31 log SMD 2 2:68 log W R 2 ¼ 0:98 Men’s suiting (Barker and Luckey, 1989) Hand¼7.87 2 14.61 LC+0.02 RT R 2 ¼ 0:97 Single knits (Chen et al., 1992) Hand¼ 2 8.4+20.9 MIU+3.4 log W R 2 ¼ 0:95 Double knits (Chen et al., 1992) Hand ¼ 25:3 þ 5:2 log SMD 2 4:2 log B R 2 ¼ 0:99
Table III. Examples of KES hand translations from NCSU studies
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clothing buffers and dissipates metabolic heat and moisture. The latter relates to the interaction of the clothing with the senses of the wearer, particularly with the tactile response of the skin.
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Thermophysiological comfort Thermophysiological comfort has two distinct phases. During normal wear, insensible perspiration is continuously generated by the body. Steady state heat and moisture vapor fluxes are thus created and must be gradually dissipated to maintain thermoregulation and a feeling of thermal comfort. The clothing becomes a part of the steady state thermoregulatory system. In transient wear conditions, characterized by intermittent pulses of moderate or heavy sweating caused by strenuous activity or climatic conditions, sensible perspiration and liquid sweat occur and must be rapidly managed by the clothing in order to maintain thermal regulation. The behavior of clothing in these two different domains may be predicted by certain measurable fabric properties, including thermal insulation, water vapor permeation resistance, moisture transport and moisture vapor buffering index (Umbach, 1988). Steady state heat and moisture transfer, key parameters in clothing comfort, can be measured using sweating guarded hot plates, or skin models. One skin model, used at NCSU employs the Kawabata Thermolabo device (Kawabata et al., 1985) in conjunction with an environmental control system. As shown in Figure 1, the NCSU thermal analyzing system consists of three parts: a controlled environmental chamber, a component that simulates skin or body heat loss, and a computer analyzing system.
Figure 1. NCSU thermal analyzing system
Heat and moisture vapor transfer are simultaneously measured using a From fabric hand sweating hot plate featuring simulated sweating glands supplying water to the to thermal heated surface of the plate. Indices of comfort are calculated from heat transfer comfort measurements including thermal insulation (I ), moisture vapor permeability index (im), and the predicted thermophysiological comfort limits. Our research uses a model developed by Woo and Barker (1988) to calculate a comfort range 185 in terms of heat generated. The model is based on the first criterion of clothing comfort which holds that the net metabolic heat generated (Mn) must be dissipated through garments worn (Q ). Body heat is lost through garments by both thermal energy transfer (H ) and evaporative transfer (E ), as represented in the following formula: Mn ¼ Q ¼ H þ E This equation has a minimum value, H, which is sensible heat transfer only at sweat wetted area ðSWAÞ ¼ 0 and a maximum value at fully wetted condition; i.e. SWA ¼ 1: The range between the minimum and maximum values represents the theoretical thermoregulation region satisfying the first criterion for comfort. In fact, the limit of 20 per cent SWA has been suggested as the second comfort limit. Applying comfort limit, 0 , SWA , 20 per cent, to the above equation results in: H , M n , H þ 0:2E Applying Woodcock’s energy dissipation formula (Woodcock, 1962a, b) gives the following thermal comfort limits for the 20 per cent and 100 per cent sweat wetted conditions: Comfort limit ¼ ð6:46=I Þ½ðT s 2 T a Þ þ 3:3im ðP s 2 P a Þ Thermoregulation limit ¼ ð6:46=I Þ½ðT s 2 T a Þ þ 16:5im ðP s 2 P a Þ This generalized equation is derived from Woodcock’s (1962a, b) equation for energy dissipation from the body into an ambient environment. It assumes that the thermal comfort zone can be extended by evaporative heat transfer in addition to dry heat transfer. The model contains three groups of functional parameters: those that are a function of fabric type (I, im), those that are a function of environment (Ta, Pa, air velocity), and a parameter that is a function of amount of metabolic heat generated (Mn). Application of this thermophysiological comfort model is discussed in studies conducted at NCSU (Barker and Choi, 2001; Barker et al., 2000; Barker and Scruggs, 1996; Hatch et al., 1990).
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Sensorial comfort Sensorial comfort is determined, to some extent, by moisture transport and moisture vapor buffering capacity. At NCSU, a specially developed dynamic sweating hot plate is used to assess fabric and microclimate response to pulsed heat and moisture loads. With this apparatus, illustrated in Figure 2, a momentary vapor pressure gradient is created using a diffusion column with a shuttering device housed in an environmental chamber. Strategically placed high sensitivity/rapid response probes track the moisture and temperature pulse history in the microclimate. The moisture vapor buffering capacities of the test fabric are characterized by the following calculated parameters. S10, the rate of increase in the microclimate relative humidity occurring during a 10 min period following initiation of the sweat pulse; DRHmax, the maximum increase in microclimate humidity created by the simulated sweat pulse; and Td, the time required for the microclimate humidity to return to a steady level following termination of the sweat pulse. Fabrics possessing the best moisture vapor regulation performance should display the lowest values in the quantities described above. Additionally, the combined buffering response was estimated using the following moisture vapor regulation index: Bd ¼
D S 10 ·DRH max ·T d
where D is constant (1000) to give the Bd value a certain range. Higher values of the sweat buffering parameter, Bd, indicate advantageous moisture vapor modulating capabilities in transient sweating conditions.
Figure 2. NCSU dynamic sweating hot plate
Application of this device to assess clothing comfort is discussed by Barker From fabric hand and Choi (2001). to thermal
comfort Liquid moisture management The ability of a clothing material to transport moisture from sweat wetted skin is crucial to perceived wear comfort. A modified gravimetric absorbency testing system (GATS) is used at NCSU to measure the moisture accumulation associated with the wicking of liquid moisture from sweating skin. The GATS procedure measures demand wettability. The test indicates the lateral wicking ability of the fabric, or the ability of the material to take up liquid in a direction perpendicular to the fabric surface. The GATS apparatus was modified to incorporate a special test cell and cover to assess absorption behavior in the presence of evaporation (Figure 3). In this arrangement, liquid is drawn from a fluid reservoir by the capillary action of the fabric. The hydrostatic pressure of the fluid delivery system is adjusted by controlling the position of the sample platform. Liquid is delivered to the test material placed on a porous plate. Numerous pins, distributed over the area of the test surface uniformly restrain the test fabric. The amount (grams) of liquid siphoned from the reservoir is recorded as a function of time. These data are used to calculate absorption capacities and rates, and the percentage of moisture evaporated by the fabric. Applications of this device are discussed by Barker and Choi (2001).
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Figure 3. Gravimetric absorbency testing system (GATS)
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Measuring warm/cool feeling The Kawabata thermal tester (Thermolabo) is used to measure the warm/cool feeling offered by the fabrics. Such a feeling, which is generated when fabric initially contacts the skin, is related to the heat flow between the skin and the contacted object. Rees (1941), Hollies et al. (1953), and Kawabata et al. (1985) have investigated the correlation between transient heat flux and the warm/cool feeling. Kawabata et al. (1985) have reported that transient heat flux significantly affects clothing comfort in next-to-skin fabrics. Figure 4 shows the principle used by Kawabata’s Thermolabo device to measure the warm/cool sensation of fabrics. When a preheated hot plate (as a simulator of human skin) is placed on a fabric sample, a heat flux versus time curve is generated. Maximum heat flow (qmax) is measured for a fraction of a second after the hot plate contacts the fabric, a time that approximates the warm/cool feeling experienced when fabric is placed on skin. The qmax value depends on the heat capacity and conductivity of the fabric and on the area of contact established between the skin and fabric surface. Contact area is the most important determinant of how warm or cool a fabric feels to an individual. It is not surprising, therefore, that the surface character of the fabric has great influence on this sensation: a rough fabric surface reduces the area of contact appreciably, and a smoother surface increases the area of contact and the heat flow, thereby creating a cooler feeling. Because qmax is influenced by a combination of fabric surface and thermal properties, it can be expected to be an important predictor of next to skin fabric contact comfort. NCSU studies have confirmed the correlation between Thermolabo measurement of qmax and subjectively perceived coolness of touch (Figure 5). Hes (1998) has also demonstrated the importance of thermal contact properties on clothing comfort.
Evaluating human comfort perception The extent of the relationship of wearer perceived clothing comfort to measured material properties is greatly influenced by garment design, cut and fit, and the end-use conditions in which the clothing is worn. Therefore, the
Figure 4. Warm/Cool feeling measuring device
From fabric hand to thermal comfort 189 Figure 5. Correlation between subjective and thermolabo ranking of cool touch for group of nonwoven fabrics (Woo, 1988)
only way to gauge the combined effects of other variables on total comfort is to obtain subjective evaluations using human subjects. Subjective evaluations, performed under controlled environmental conditions at the fabric and garment level, provide responses that can be related back to instrumentally measured physical properties of materials and for use in identifying and correcting material deficiencies. At both levels, human evaluators make ratings using specially chosen descriptor terms related to comfort feeling and on certain garment properties. The wear trial protocols used at NCSU are deliberately designed to produce conditions of physical activity and environment that cause differences in human response to the physical properties and characteristics of the worn garments to emerge. The wear protocol, based on the general approach developed by Hollies et al. (1979) is designed to include sweat generating activities that would represent a reasonable range of comfort conditions. NCSU wear trial protocols are designed to simulate the end-use wearing situations as close as possible in a controlled laboratory setting. As an example, Table IV shows a wear trial protocol designed to assess the comfort response to operating room gowns (Barker et al., 2000). The protocol features a five-period test sequence that includes periods of physical activity alternating with periods of rest, in moderate and mildly warm environmental conditions. Sweat producing exercises were incorporated, including a mild aerobic step exercise and an exercise that required upper torso dexterity and mental skill (Figure 6). Prior to initiating the wear trial, evaluators were required to sit quietly for 15 min in a moderate (218C, 65 per cent RH) environment. This was done to bring the evaluators to a relaxed condition.
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Test gowns were randomly assigned to evaluators, so that different types were worn in each test session. This practice assured that more independent ratings were obtained. Additionally, evaluators were instructed not to discuss the gowns or their ratings. An evaluation form was designed to obtain ratings of comfort and sensory tactile properties for each of the five periods of the test protocol. The first three items in the evaluation form require evaluators to rate overall comfort, warm– cool feeling, and softness of the material. The rating values of these items ranged from 1 – 7 as they appear on the evaluation form with 7 representing the most comfortable, coolest, and softest garment. Eleven descriptor terms were selected to be representative of the fabric properties that are most relevant for operating gown applications. The descriptors are stated negatively because individuals are better able to discern degrees of tactile unpleasantness than degrees of tactile pleasantness. Values of 1 – 5 were assigned in these ratings with 1¼“totally” and 5 ¼ “no sensation”
Rating period
Table IV. Wear trial protocol for O.R. gowns
Figure 6. Evaluators (performing dexterity exercise) as they rate surgical gown comfort in a climate chamber at NCSU center for research on textile protection and comfort (T-PACC)
1 2 3 4 5 a
Time (minutes)
Activity
10 15 15 5 5
Rest Aerobics/exercisea Rest Mental dexterity activityb Rest
Temperature 8C (8F) 21 21 27 27 21
(70) (70) (80.6) (80.6) (70) b
Relative humidity (per cent) 65 65 65 65 65
Notes: Mild stepping exercise with some arm movement.; A competitive table-top game of manual skill.
(do not sense any negative quality). Higher values denote a more desirable From fabric hand quality. Table V contains a list of the descriptor terms with the associated to thermal physical property of the fabric. comfort Figures 7 and 8 compare comfort ratings obtained for a single use nonwoven (A) and reusable woven cotton (B) operating room gown of identical design. These results confirm the importance of including primary sensory factors 191 in comfort analysis. They show that substantial differences do not emerge between test garments for the broad comfort descriptors of softness, thermal feeling and overall comfort vote, as these ratings are averaged over all periods of the wear test protocol (Figure 7). This finding suggests that general or composite descriptors of evaluator comfort response are too diffuse to
Sensory quality descriptor Snug Heavy Stiff Sticky Nonabsorbent Clammy Damp Clingy Prickly Nonstretchy Scratchy
Associated physical property Fit Weight Bending Moisture Moisture Moisture Moisture Moisture Surface Tensile Surface
Table V. List of comfort descriptors
Figure 7. Ratings of garments of all periods combined
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Figure 8. Ratings of garments for all periods combined
discriminate between these particular materials. On the other hand, perceived differences are more apparent when primary, or more specific ratings of skin contact sensations, such as stiffness or dampness are used (Figure 8). These studies also show the activity and/or environmental conditions that significantly influence comfort ratings over the five periods of evaluation (Figures 9 and 10). Sensorial comfort and fabric properties Sensorial comfort is mainly determined by skin contact sensations and is often expressed as feelings of softness, smoothness, dampness, clinginess, prickliness, and the like. These descriptors can be related to specific, measurable fabric, mechanical and surface properties including number of surface fibers and contact points, wet cling to a surface, absorptivity, bending stiffness, resistance to shear and tensile forces and coolness to the touch. Fiber characteristics, yarn and fabric construction and fabric finish mainly determine these properties. Figures 11 –13 show correlations observed between measured fabric properties and corresponding ratings of skin contact sensations obtained in a NCSU wear trial study of heat resistant workwear garments (Barker and Choi, 2001). These results show that the degree of correlation depends on the
From fabric hand to thermal comfort 193
Figure 9. Stiffness rating of garments by period
conditions of wear, specifically on the sweat producing activity and the temperature and humidity of the ambient environment. Therefore, during periods characterized by little physical activity, and a cool environment (periods 1 and 5), perceived garment stiffness is more highly correlated with fabric bending and shear stiffness than when wear conditions involve sweat generating physical activity, body movements or a warm and humid environment (Figure 11). Absent warm environmental conditions or sweat, attributes and properties associated with fabric aesthetics, drape and hand, are the qualities sensed by the wearer. Figure 12 shows that measured fabric surface properties, including surface roughness and contact points, associate with sensations of garment prickliness. Measured fabric contact (nk) correlates with impressions of
Figure 10. Damp rating of garments by period
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194 Figure 11. Correlation between fabric mechanical properties and perceived stiffness in wear of heat resistant workwear garments
prickliness across all the periods or conditions of wear. KES measured surface roughness index (SMD) correlates with perceived prickliness best in the initial phase of the wear trial (period 1), or before sweat producing physical exercise has occurred. The observed correlations between measured surface properties underscore the importance of the fabric interface in influencing skin contact sensations, especially against sweat-wetted skin. Figure 13 indicates that fabric cling to hydrated skin (wet-cling index, ik) is a correlated comfort factor in wear conditions associated with sweat generating physical activity or in a warm and humid environment (periods 2, 3, and 4 in the wear protocol).
Figure 12. Correlation between fabric surface properties and perceived prickliness in wear of heat resistant workwear garments
From fabric hand to thermal comfort 195
Figure 13. Correlation between fabric wet cling and perceived clinginess in wear of heat resistant workwear garments
Laboratory characterizations indicative of the nature of the fabric and skin interface, or expected contact between the fabric and skin, were made using skin test procedures employed by Umbach (1988). Measures included index of the number of contact points (nk) between the test materials and a flat surface. An estimate of the force with which a fabric clings to moist skin (Ik) was made using a procedure employed by Umbach (1988). In this apparatus, sweating skin is simulated by a sintered glass plate attached to a water supply. The test fabric is mechanically drawn across the moistened plate and the force required to draw the sample is measured and used to compute a wet-cling index. Objective measurement of clothing comfort Because human subjects vary considerably in individual physiological and psychological response, it is desirable to have a means of objectively measuring clothing comfort. NCSU uses an advanced sweating manikin for this purpose (Figure 14). The NCSU manikin is similar to the system devised by Meinander (1992). Although thermal manikin technologies have been used to evaluate clothing comfort and heat stress for many years, no other manikin systems possess the unique measurement capabilities incorporated in this manikin. The manikin is capable of internally generating a controlled supply of moisture through 187 individually controlled sweat glands. Moisture and heat loss can be continuously monitored for full clothing ensembles in a variety of climatic conditions and simulated activity levels. The ability to precisely control sweating over lengthy test periods has been lacking in previous thermal
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Figure 14. NCSU advanced sweating manikin used for comfort studies
manikin technologies. Consequently, this manikin truly represents a “new generation” manikin with unprecedented ability for simulating human physiological heat loss mechanisms. The manikin is housed in a climatic chamber. Water is supplied from a reservoir, placed on a balance near the ceiling in the chamber. A microvalve system in the manikin distributes the water to the 187 sweat glands, and the computer system allows individual control of each sweat gland. The operator controls the water supplied to each of the simulated sweat glands, by setting the desired “sweating” rate. Individual “sweat glands” are calibrated with software controlled routing. Based on calibrated values, the software algorithm
time proportions the valve openings to supply the desired water delivery rate. From fabric hand The valve supplying each sweat gland is opened after a precision balance has to thermal established the weight of the supplied water. When the sweat gland is closed, comfort the water supply is reweighted. The time dependent weight change determines the “sweating” rate for each individual sweat gland. The condensed water on the dressed manikin is recorded by measuring the change in the weight of the 197 clothed manikin during the test. This measurement is made from the output of the sensitive balance from which the manikin is suspended. Test garments are weighed before and immediately after the test. This is done to estimate the amount of moisture condensation in the individual clothing layers. Moisture condensation in the skin material of the manikin is calculated as the total weight change subtracted by the moisture condensed in the clothing. An example, showing application of the NCSU sweating thermal manikin can be found in Deaton et al. (2001). Conclusions Objective measurement has progressed far since Pierce’s pioneering work. Modern laboratory devices and measurement systems are not only capable of reliably predicting human sensory response to fabric touch, but can explain sources of discomfort associated with material properties and garment design. The diverse instrumented systems developed by Professor Kawabata have had a profound impact on the evolution of the science of objective measurement for textiles. In spite of advances in instrumented measurement, much remains to be learned about human sensory response to textiles and the effects of surrounding conditions on comfort assessments. Recent research has shown the importance of isolating complex effects of tactile comfort on the total comfort equation. These include problems associated with adjectives such as stiff, scratchy, clingy, prickly, etc. Recent work suggests that tactile input may be the deciding comfort-predicting factor. A deeper understanding of tactile comfort and the material properties that affect it may remove a major obstacle to the translation of measured material physical properties to subjective human comfort response. Our studies have shown that vapor transport and thermal transfer properties are often necessary but not sufficient predictors of comfort. The specific mode of moisture transport through the clothing system seems to play a role as does the tactile, mechanical skin sensation associated with so-called cling and prickliness. These studies demonstrate that sensorial comfort is a complex function of material properties as well as climatic conditions of wear. They illustrate the benefits of an approach to comfort assessment that is based on a multilevel concept, advancing from the investigation of fabric properties to, ultimately, analysis of complete garment systems. They confirm the value of
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the measurements made by the KES when used as a component of comprehensive research, designed to explain complex human response to clothing comfort. Measurement technologies for the virtual age must now be considered. If we are to tailor textile products to the preference of the consumer, or develop virtual handling of fabrics for electronic retailing, continued advances are needed in objective measurement, in fabric and garment engineering and in our understanding of human and clothing interactions. As Hearle (1993a, b) has observed, if fabric hand is to enter the data space, we must contemplate measuring the unmeasurable (Hearle, 1993a; b). Study is needed in the development of objective measurement systems for garment level evaluations. The development of manikin technologies as increasingly realistic simulators of human thermophysiological and even human sensorial response represents an exciting frontier for future research. References Barker, R.L. and Choi, S. (2001), “Relating fabric properties to wear comfort of protective garments”, Prodeedings of Textile Institute 81st World Conference, Melbourn, Australia, April. Barker, R.L. and Luckey, G.S.H. (1989), “Objective evaluation of the hand of mens’ suiting fabrics – relationship between measured fabric properties and subjective hand ratings,” Proceedings of the 39th Annual Technical Conference American Society of Quality Control. Barker, R.L. and Scruggs, B.J. (1996), “Evaluating the performance of fabrics used in nuclear protective apparel“, in, Performance of Protective Clothing, ASTM STP 1237, Johnson, Mansdorf, (Eds) American Society for Testing and Materials, Philadelphia, PA Volume 5. Barker, R.L., Scruggs, B.S. and Shalev, I. (2000), “Evaluating operating room gowns: comparing comfort of nonwoven and woven materials”, International Nonwovens Journal, Vol. 9 No. 1, pp. 23-9. Barker, R.L., Radhakrishnaiah, P., Woo, S.S., Hatch, K.L., Markee, N.L. and Maibach, H.I. (1990), “In vivo cutaneous and perceived comfort response to fabric, Part II: mechanical and surface related comfort property determinates for three experimental knit fabrics”, Textile Research Journal, Vol. 60 No. 8. Brand, R.H. (1964), “Measurement of fabric aesthetics analysis of aesthetic components”, Textile Research Journal, Vol. 34, pp. 791-804. Chen, P., Barker, R.L., Smith, G.W. and Scruggs, B.J. (1992), “Handle of weft knit fabrics”, Textile Research Journal, Vol. 62 No. 4, pp. 200-11. Dawes, V.H. and Owen, J.D. (1971a), “The assessment of fabric handle Part I: stiffness and liveliness”, Journal of the Textile Institute, Vol. 62, pp. 233-44. Dawes, V.H. and Owen, J.D. (1971b), “The assessment of fabric handle Part II: smoothness”, Journal of the Textile Institute, Vol. 62, pp. 245-50. Deaton, A.S., Thompson, D.B. and Barker, R.L. (2001), Evaluation of Protective Clothing for Comfort, INDA Technical Symposium, Miami, FL. Hatch, K.L., Woo, S.S., Barker, R.L., Radhakrishnaiah, P., Markee, N.L. and Maibach, H.I. (1990), “In vivo cutaneous and perceived comfort response to fabric Part I: thermophysiological comfort determinations for three experimental knit fabrics”, Textile Research Journal, Vol. 60 No. 7.
Hearle, J.W.S. (1993a), “Can fabric hand enter the data space?”, Textile Horizons International, pp. 14-16. Hearle, J.W.S. (1993b), “Can fabric hand enter the data space? Part II: measuring the unmeasurable”, Textile Horizons International, pp. 16-20. Hes, L. (1998), “Optimization of the shirt fabric composition from the point of view of their appearance and thermal comfort,” 27th Mt. Fuji Textile Research Symposium, Japan. Hoffman, R.M. and Beste, J.F. (1951), “Some relations of fiber properties to fabric hand”, Textile Research Journal, Vol. 21 No. 2, pp. 66-77. Hollies, N.R.S., Bogaty, H., Hintermaier, J.C. and Harris, M. (1953), “The nature of a fabric surface: evaluation by a rate-of-cooling method”, Textile Research Journal, Vol. 23, pp. 763-9. Hollies, N.R.S., Custer, A.G., Morin, C.J. and Howard, M.E. (1979), “A human perception analysis approach to clothing comfort”, Textile Research Journal, Vol. 49, pp. 557-64. Howorth, W.S. and Oliver, P.H. (1958), “The application of multiple factor analysis to the assessment of fabric handle”, Journal of the Textile Institute, Vol. 49 No. 11, pp. T540-53. Kawabata, S. and Niwa, M. (1980), The Standardization and Analysis of Hand Evaluation, The Hand Evaluation and Standardization Committee, 2nd ed., The Textile Machinery Society of Japan, Osaka. Kawabata, S., Niwa, M. and Sakaguchi, H. (1985), “Application of the new thermal tester “thermolabo” to the evaluation of clothing comfort,” objective measurement application to product design and process control, Kawabata, S. Postle, R. and Niwa, M. Eds., Journal of Textile Machinery Society of Japan. Lundgren, H.P. (1969), “New concepts in evaluating fabric hand”, Textile Chemists and Colorists, Vol. 1 No. 1, pp. 35-45. Matsuo, T., Nasu, N. and Saito, M. (1971), “Study on the hand; Part 2: method for measuring hand”, Journal of Textile Machinery Society of Japan, Vol. 24, pp. T58-T68 English translation 17, 92-104, 1971. Meinander, H. (1992), “Determination of clothing comfort properties with the sweating thermal manikin,” Proceedings of the Fifth International Conference on Environmental Ergonomics, Maastrich, TNO Institute for Perception, Soesterberg, The Netherlands, pp. 40-1. Pierce, F.T. (1930), “The handle of cloth as a measurable quantity”, Shirley Institute Memoirs, Vol. 9 No. 8, pp. 83-122. Pontrelli, G.J. (1990), “Comfort by design”, Textile Asia, Vol. 21 No. 1, pp. 52-61. Rees, W.H. (1941), “Transmission of heat through textile fabrics”, Journal of the Textile Institute, Vol. 32, pp. T149-66. Umbach, K.H., et al. (1988), “Physiological tests and evaluation models for the optimization of the performance of protective clothing“, in, Environmental Ergonomics, Mekjavic, I.B., (Eds) Taylor & Francis, New York/London pp. 139-61. Vaughn, E.A. (1975), “Studies of fabric hand,” Proceedings of the AATCC Annual Technical Conference. Vohs, K.M., Barker, R.L. and Mohamed, M.H. (1985), “Objective evaluation of fabrics woven with air jet yarns, Part II: hand properties,” objective measurement: application to product design and process control, Kawabata, Postle, Niwa, Eds., Journal of Textile Machinery Society of Japan, pp. 130-3. Winakor, G., Kim, C.J. and Wolens, L. (1980), “Fabric hand: tactile sensory assessment”, Textile Research Journal, Vol. 50, pp. 601-10.
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Woo, S.S. Comfort Properties of Nonwoven Fabrics in Extreme Hot and Cold Environment Ph.D. Dissertation North Carolina State University. Woo, S.S. and Barker, R.L. (1998), “Using novel methods to measure the heat and moisture transport properties of polyester and cotton knit fabrics,” Proc. Fiber Producer Conference – 88, Greenville, SC, May. Woodcock, A.H. (1962a), “Moisture transfer in textile systems, Part I”, Textile Research Journal, Vol. 32, pp. 628-33. Woodcock, A.H. (1962b), “Moisture transfer in textile systems, Part II”, Textile Research Journal, Vol. 32, pp. 719-23.
The current issue and full text archive of this journal is available at http://www.emeraldinsight.com/0955-6222.htm
Recent developments in materials for use in protective clothing
Recent developments in materials 201
Roshan Shishoo IFP Research AB, Mo¨lndal, Sweden Keywords Protective clothing, Fabrics Abstract This paper outlines the innovations in high functional and high performance fibres for applications in protective clothing, including fibres for flame and heat protection. It also describes some typical woven and non-woven constructions for such applications. And presents the trends in producing smart textile materials, capable of interacting with human/environmental conditions.
Background Millions of people world-wide have working environments which expose them to specific risks from which their bodies need protection. In many industrial sectors, military and energy services, hospital environments, human beings are subjected to various types of risks and each sector has its own requirements for protective clothing. The end-use applications for protective clothing include .
chemical splash and vapour protection,
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clean-room apparel,
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cut resistant gloves,
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dirt and dust,
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fire fighting,
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ballistic protection,
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paint spray,
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puncture-resistant clothing,
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hospital textiles, and
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dry chemical handling.
The performance requirement of all types of protective clothing often demand the balance of very different properties of drape, thermal resistance, liquid barrier, water vapour permeability, anti-static, stretch, etc. The seemingly contradictory requirement of creating a barrier, e.g. towards heat, cold, chemicals, bacteria, and breathability in high-functional clothing has placed
International Journal of Clothing Science and Technology, Vol. 14 No. 3/4, 2002, pp. 201-215. q MCB UP Limited, 0955-6222 DOI 10.1108/09556220210437167
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challenging demands on new technologies for producing fibres, fabrics and clothing design. Among the contributing factors responsible for successful marketing of such products have been advances in polymer technology and production techniques for obtaining sophisticated structures of fibres, yarns and fabrics. Improved fibre spinning techniques in melt spinning, wet spinning, dry spinning and new techniques such as gel spinning, bicomponent spinning, microfibre spinning, have made it possible to produce fibres with characteristics more suitable for use in protective clothing (Shishoo, 1988). Many of the requirements for protective clothing are aimed at solving a set of problems such as .
Improved protection – against the environment
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Maintenance of thermo-physiological comfort – or survival in extreme conditions.
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Improved compatibility – between and within different components in the clothing assembly.
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Reduction in weight and bulk – especially load carriage systems and ballistic protective clothing.
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Integration of clothing items – in which the clothing items are considered to be parts of a multi-role system.
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Reduction of life cycle costs – future systems may be more expensive, but may be more effective, durable, may consist of fewer components, and could be recyclable.
In this paper innovations in fibres in terms of high functional and high performance fibres for applications in protective clothing will be highlighted. These include fibres for flame and heat protection. Description of some typical woven and non-woven constructions for such applications will also be given. The trends in producing smart textile materials capable of interacting with human/environmental conditions will be presented. These include materials for environmental protection, high performance wicking materials, waterproof/water vapour permeable materials, etc. Innovations in fibres The evolution of fibre developments have gone through the phases of conventional fibres, high-functional fibres and high-performance fibres (Mukhopadhyay, 1993). Improved fibre spinning techniques in melt spinning, wet spinning, dry spinning and new techniques such as gel spinning, bicomponent spinning, microfibre spinning, have made it possible to produce fibres with characteristics more suitable for use in protective clothing.
Today a wide range of high-performance fibres is commercially available for Recent technical and industrial applications. Speciality fibres already established developments in include: materials (1) Aramid fibres .
p-aramid fibre to provide high strength and ballistics.
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m-aramid fibre to provide flame and heat resistance.
(2) Ultra-high tenacity polyethylene fibres (UHMWPE) Gel spun, ultra-high molecular weight polyethylene fibres with extremely high specific strength and modulus, high chemical resistance and high abrasion resistance. (3) Polyphenylene sulphide fibres (PPS) Crystalline thermoplastic fibre with mechanical properties similar to regular polyester fibre. Excellent heat and chemical resistance. (4) Polyetheretherketone fibres (PEEK) Crystalline thermoplastic fibre with high resistance to heat and a wide range of chemicals. (5) Novoloid (Cured phenol-aldehyde) fibres High-flame resistance, non-melting with high resistance to acid, solvents, steam, chemicals and fuels. Good moisture regain and soft hand. (6) Polybenzimidazole fibres (PBI) Moisture regain 15 per cent, high resistance to chemicals especially at elevated temperatures.
Aramid fibres A number of different types of p-aramid fibres are commercially available as the basis material for protective clothing. The brands include Kevlar by DuPont, Twaron by Acordis and Technora by Teijin. Para-aramid fibre’s combination of high strength, non-flameability and high temperature resistance makes this type of fibre suitable in applications such as .
ballistic protection in armour vests and helmets,
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cut through protection in safety gloves, aprons, work wear and shoes for high risk jobs,
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high-temperature protection, e.g. spatter-resistant clothing.
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These fibres are also well-known for their dynamic energy absorbing properties (Van Zijl et al., 1999). For thermal stability purposes m-aramid fibres has the right attributes. Meta-aramids have high temperature resistance, moderate tenacity and low modulus but excellent resistance to heat (Gorashi and Stocks, 1995). These fibres are very useful when outstanding thermal protection and electrical insulation properties are required. The brands include Nomex and Corex. The m-aramid fibre Kermel is currently used in protective clothing. It has excellent thermal properties against high temperature, “flash” exposures and is easily blendable with other fibres (Cassat and Hoessi, 1995). DuPont-Toray in Japan have also produced new spun-dyed Kevlar p-aramid fibres. Twaron made by Acordis is also being produced as a microfibre with a dtex of 0.93. High-performance polyethylene fibres UHMPE with high modulus and high strength, together with exceptional strength-to-weight ratios, are available with trade names Dyneema from DSM, Spectra from Allied Signals, Tekmilon from Mitsui. This type of fibre has .
very high specific strength, specific modulus and high energy to break,
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low specific gravity,
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very good abrasion resistance,
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excellent chemical and electrical resistance,
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good UV resistance,
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low moisture absorption.
In protective clothing applications, many impact helmets used by runners and mountain climbers, for example, are made of UHMPE composites. High performance PE fibres are also used for protection against cutting, sawing, puncturing, and ballistics. A very high growth in the use of fibres such as Dyneema and Spectra is predicted for use as body armour. Knitted fabrics made of UHMPE are used for personal protection viz., gloves, chain saw protection and fencing suits (Jacobs and Mencke, 1995; Van Gorp and Van der Loo, 1995). Novoloid fibres Kynol woven and non-woven fabrics display the following advantages
In flame .
high flame resistance; non-melting at any temperature,
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retention of textile integrity; no embrittlement or breakage,
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minimal evolution of smoke, nearly no shrinkage,
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virtually no toxic off-gassing (no HCN, halogens, etc.).
And in general .
outstanding resistance to acids, solvents, bleaches, fuels, steam and other chemicals,
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excellent thermal and electrical insulation,
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good moisture regain and soft hand; comfortable to wear and use,
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light weight (specific gravity 1.27),
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available as 100 per cent novoloid and in various blends.
Melamine-based fibres Basofil (BASF), a high-temperature and fire resistance fibre, is a melaminebased staple fibre which has a LOI of 31– 33 with no melt dripping and a continuous service temperature of about 2008C (Berber, 1995; Ott, 1995). PEN and PBO fibres Recently some new exciting fibre types such as PEN and PBO have been introduced in the market. Compared to the standard polyester, PEN, polyethylene-2,6-naphtalat, fibre yarns have a significantly higher modulus, high-dimensional stability, higher glass-transition temperature and better resistance to hydrolysis and LOI of 31. Toyobo’s high performance PBO fibre, Zylon, p-phenylene-2,6benzobisoxazole, has strength and modulus far exceeding those any of the known fibres. PBO fibre has the decomposition temperature of 6508C, tenacity 5 – 8 GPa and modulus of 180 – 250 Gpa (Shishoo, 2000; Technical information, 1998, 1999). Other types The market for FR-treated cellulosic fibres for use in apparel. Flame-retardant armaments made from cellulosic fibres continue to find application even in most demanding work environments such as those encountered by firefighters.
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Polyester Trevira is another example of a flame retardant fibre. Flameresistant heavy-duty PES multifilament yarns are also available from, e.g. KoSa.
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Electro-conductive fibres Many synthetic fibres are excellent electrical insulators and are therefore susceptible to static charges. One approach to solve this problem is to increasing the fibre conductivity by applying conductive finishes to the surface. Most of these finishes are easily removed by washing, however, they do not provide durable protection against the hazards of static electricity. Metal fibres have been successively replaced by electro-conductive organic fibres in the past decade. One commercial approach to make a permanently antistatic fibre is to blend a conducting polymer into the non-conducting fibre. Many polyblend fibres of this type are now commercially available (Shishoo, 1988). Novel yarn spinning technology Novel yarn spinning technologies are commercially available now for producing hybrid yarns for various applications including protective clothing. Two technologies are used to manufacture such yarns .
the conventional spinning by intimately blending two different yarns,
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the core yarn spinning, making a core of a certain fibre type covered with a sheath of a different fibre type.
One can thus combine the functions of two different fibre qualities to produce fabric of varied functions. For example the core can be made of p-aramid, the sheath of m-aramid, cotton or polyester. Sensitive core-materials can be protected by the sheath fibres (Bontemps, 1995). High-functional and high-performance fabrics Microfibre based light woven constructions The very first example within this group is the ventile fabrics made of 100 per cent cotton, where a very large reduction in the interfibre pore sizes is achieved as a result of swelling in fibres in wet state. New techniques for spinning extremely fine polyester filaments of 0.1 – 0.3 denier have resulted in many interesting developments of woven and nonwoven structures of high-functional characteristics. For example the superfine yarns are woven into various constructions such as Oxford and taffeta, in which individual filaments are packed so tightly that the resultant fabric develops high hydrostatic resistance in combination with good water-vapour
permeability and drape. These properties can be further improved by treatment Recent with liquid repellent finishes. developments in Some of the most interesting developments lie in the production of multimaterials layer knitted and woven constructions. A multi-knit fabric of two or threelayered structure using 100 per cent polyester and polypropylene yarn has characteristics of quick water absorption, ability to evaporate water and a dry 207 touch, being capable of transporting perspiration from the skin to the outer surface and then quickly dispersing it (Shishoo, 1988). Breathable fabrics Laminated fabrics (microfibrous membrane). One of the most significant developments in breathable waterproof was the introduction of the GORE-TEX rainwear fabric in 1976. GORE-TEX is a microporous polymeric film made of polytetrafluoroethylene (PTFE). The GORE-TEX film is supposed to contain micropores of size 0.2 micron at the rate of more than 1.3 billion/cm2, and it provides a barrier to water, airborne particles and bacteria. Being very hydrophobic, PTFE will resist wetting of the surface. At the same time because of the pore distribution water vapour can readily diffuse through the film. GORE-TEX film has been bonded to a variety of substrates and constructions. Both two-layer construction, where a single layer of fabric is bonded to one side of the film, and three-layer, where fabrics are bonded to both sides of the film, are available as high functional fabrics. A similar principle is used in MICRO-TEX film from Japan. A fabric for outwear is laminated with porous film of PTFE resin containing micropores of size 0.6 micron at the rate of approx. 1 billion/cm2(Shishoo, 1988). Coated fabrics (microporous coating). Polyurethane is one of the most widely used polymers for coating apparel fabrics. One reason for this is the availability of numerous combinations of polyols, isocynates and amines for its synthesis. Poromeric polyurethane coatings are produced by either a wet coagulation process or a direct coating system. The general procedure in a wet coagulation system is to impregnate the fabric with a special polyurethane formulation dissolved in an appropriate solvent. Prior to evaporation of the solvent the coated fabric is immersed in a water bath which precipitates a coherent but highly porous polyurethane layer. In a direct coating system, the microporous structure develops during subsequent drying and curing process. Numerous developments in microporous polymer structures for use in direct coating, and as a film for laminating into two or three layer structures, have taken place world-wide. These microporous structures function by allowing the passage of water vapour molecules (approx. 0.0004 micron in dia.) whereas large diameter (.100 micron) water drops get blocked by these structures. For a given porosity and thickness of the coating the water vapour permeability increases if one reduces the pore size (Shishoo, 1988).
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Laminated fabrics (hydrophilic membrane). High-functional fabrics are engineered by combining with hydrophilic membranes. Water-vapour transmission through these membranes is achieved by the physical processes of adsorption, diffusion and desorption. Because the membrane is a non-porous material one can expect no clogging of pores.
208 Smart coatings Important developments are envisaged in making multifunctional coated or laminated fabrics for different applications. For example some new innovative functional textiles for protective clothing were introduced by GORE last year. In the GORE-TEX Airlock breathable textile, it is claimed by GORE that fire fighting clothing made from this material combines the functions of protection, comfort and heat insulation. GORE-TEX Antistatic breathable textile combines protection, comfort and antistatic protection. GORE-TEX anti-static is a functional textile for protective clothing which combines several functions: permanent full-surface antistatic protection, weather protection, heat and flame protection. Additionally, this garment provides the wearer with excellent comfort. This innovative, durable, antistatic protection is based on nano-technology, a field which has not been applied in functional textiles before. Electrically conductive nano-particles are homogeneously and durably anchored in the fibrils of the windproof, waterproof and breathable GORE-TEX membrane, creating an electrically conductive network throughout the membrane. The grid formed in this way is 100,000 times denser than conventional conductive grids. This quasi-homogenous structure prevents the formation of isolated chargeable areas and critical levels of electrostatic energy because the charges permanently flow in all directions. The electrostatically dissipative effect of GORE-TEX anti-static is based on two mechanisms: electrical influence and micro-discharges. GORE-TEX Airlock is a functional textile which was developed by Gore for the special needs of fire fighters. This is the first time that a single product combines an effective heat shield with a moisture barrier and high physiological comfort due to its inherent breathability. The concept of this product is to eliminate the conventional, bulky, thermal insulation layer and substitute it by a protective air cushion. Dots consisting of foamed silicone are discontinuously applied to a fibre substrate and anchored within the microporous GORE-TEX membrane. They measure only a few millimeters in height, creating a defined air cushion between the adjacent flame-retardant face fabric and the inner lining. Fire fighting clothing made from this material is considerably more comfortable to wear than conventional constructions due to significantly improved breathability, perspiration transport, absorption and quick dry properties (Avantex, 2000).
AKZO Nobel has introduced SYMPATEX, which is a non-porous high Recent breathable polyester membrane. This product is washable and dry cleanable developments in and is claimed as watertight, windtight and having high wear resistance. Its materials development included work in polymeric composition, membrane process, laminating process and the seam-sealing technique. AKZO Nobel developed a special seam-sealing tape for this purpose (Spijkers, 1995). 209 It is desirable from many aspects that one looks at coatings in coated and laminated structures which are able to contribute to properties other than strength and barrier. The polymeric backbone is of potentially great importance. The polymeric components in these structures could be given smart functions such as shape memory and phase-change effects. The polymer layer can also be embedded with sensors for registration of strains, stresses, stability, colour change, moisture, liquid transport etc. In the past few years there have been some interesting developments taking place as regards smart materials where the value-added function has been achieved by suitable coating and laminating techniques. Among these developments one can mention photoluminescent materials, shape memory polymers, phase-change materials, heat insulative tarpaulin, light-protective sheets etc.
Thermal insulation materials Waterproof and breathable fabrics are often used in combination with synthetic heat insulating materials. Because of fashion and function requirements and demands, developments have taken place for producing thin but warm fibrefills. Since air has a very low conductivity in the newly developed materials, heat insulating property is imparted and improved by confining as much air as possible in the microspaces between and/or within the fibres and thereby checking heat losses by convection. These materials are made by producing Coweb-like structures from superfine fibres, or by making the fibres hollow in order to contain air and prevent air movements. These new materials have 2– 3 times as much thermal insulation as that of conventional polyester wadding or down of the same thickness (Shishoo, 1988).
Non-woven protective clothing Protective coveralls, suits, gowns, lab coats and accessories are used in industry and institutions to protect workers from exposure to hazardous materials and to protect sensitive products from human contamination. Nonwoven clothing are used for limited use protective clothing and as components in reusable clothing. Spun-bonded olefins are the leading materials used and are often used in composites with barrier films.
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Medical/surgical disposal represent about 11 per cent of the European nonwoven market whereas, these disposals are the second largest market for nonwoven in the U.S. This product group includes surgical packs, drapes and gowns, surgical face masks, caps and head covering, patient and staff clothing. Spun-laced pulp/polyester, spun-bonded, spun-bonded/meltblown components and wet laid pulp/polyester non-wovens are the leading fabric types used for medical disposables. Heatbonded and calendered polyethylene spun-bonded fabric Tyvek from DuPont is a fine example of a very successful non-woven material for protective clothing. Tyvek 1431N, non-woven structure made of 100 per cent HDPE offers excellent particle hold and properties down to particle size of 3 microns. For protection from particles smaller than 3 microns, DuPont recommends the coated fabric Tyvek C and laminated fabric Tyvek F. For dust protection Corvin Company’s spun-bonded non-woven “Multidenier” using different spun-bonded technologies demonstrate a new group of innovative products (Bernstein and Thiele, 1995). Photoluminescent material Inorganic luminescent pigments are composed of zinc-sulphide crystals. The crystal lattice of the pigment is able to absorb visible high energy and store that energy through various levels of the electrons. The energy will be set free under the emission of light when the activating light source disappears. This process can be repeated as often as required. The cause of photoluminescence is the transport of electrons. These materials are free of radioactive substances and are non-toxic. The size, formation and quantity of the zinc intensity of the light emission. The base material carrying the photoluminescent is a softcoating blend of polyester and cotton (Simpson, 1995). Interactive textile materials We will see continued efforts in the production of interactive textiles. There have been some interesting developments taking place in recent years regarding smart textile materials. These materials readily interact with human/environmental conditions to produce change in material properties. The shape memory polymers and phase-change materials embedded in fabric layers will be able to interact with a human body and produce thermorequlestoring effect by affecting the microclimate. We will also see, for example a new range of reactive materials for flame and heat protection. These types of materials are designed to provide minimal insulation during normal wear, but maximum insulation when the heat threat impinges. Among the novel treatments mentioned, Intumescent treatments
which normally are in the form of thin, low insulation coatings on a lining Recent fabric: when activated by excessive heat or flames the formulation swells developments in instantly to form an inert insulative char, protecting the wearer. materials Shape memory polymers The shape memory effect is observed in metal alloys and polymers, and results in an object reverting to a previously held shape when heated. Early shape memory polymers were blends of glassy thermoplastics and elastomers. More recently, Mitsubishi has made shape memory polyurethanes available. These are thermoplastic polymers that can have reversion temperatures in the range 2 308C to +1008C. Shape memory polyurethanes are block copolymers having hard and soft segments. The hard segments, which contain the urethane linkage and chain extenders, are present in sufficient numbers to form a continuous crystalline phase. Constituted from polyether or polyester diols, the soft segments make up the glassy phase (Russel et al., 1999; Technical Textiles International, 1999). In effect, the shape memory polyurethanes are thermoplastic elastomers that can have glass transition temperatures within an unusually interesting range. For instance, this includes ambient temperatures (about 258C), the temperature of the human body (378C) and the temperature of boiling water (1008C). The prototype design is a laminated film consisting of: .
a film of shape memory polymer having a glass transition temperature of 258C;
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a layer of a compatible elastomeric, a thermoplastic polyurethane having a much lower glass transition point (such as a conventional shoesoling grade).
The films can be made on an extrusion/calendering line and the laminates can be compression-moulded using conventional equipment. To promote the circulation of air and moisture vapour within the interstitial space, as well as reducing the weight of the film, holes and cut-outs can be made in the laminate. On cooling below 258C, the shape memory layer should shrink linearly by some 3 per cent and become rigid while the conventional elastomer remains largely unaltered. As a result, an out-of-plane deformation of the laminate is expected to occur. It is anticipated that deformed films of these laminates will provide a reversible response to cold conditions. Phase change materials Protective textiles with microencapsulated phase change material (PCM) are now commercially available, e.g. Outlast Technologies. The PCMs used in this
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technology consists of carbohydrates with different chain lengths, whose phase change takes place in a temperature range close to that of the human skin (Pause, 1995; 1999; Technical Textiles International, 1999; Leitch and Tassinari, 2000). The PCMs, are encapsulated in small spheres in the order that they are contained when in a liquid state. The microcapsules have an approximate diameter of 1 – 10 mm and are resistant to abrasion, pressure, heat and chemicals. At present this technology is only applicable to acrylic fibres using the wet-spinning process. For coating applications, the PCM microcapsules are dispersed in, e.g. a polyurethane coating which is then applied to a fabric. For foam applications, the PCM microcapsules are dispersed in a polyurethane foam matrix. These foams are often laminated to a fabric. Textile structures with PCM microcapsules for protective clothing have the following interactive functions .
absorption of surplus body heat;
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an insulation effect – s caused by heat emission of the PCM into the textile structure;
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a thermo-regulating effect – which keeps the microclimate temperature nearly constant.
Exothermic functions in clothing For many years, Japan has been an innovation gateway in the man-made fibre high-tech and high-performance textile sectors. Very interesting developments in heat retention and exothermic functions for protective clothing and sportswear have taken place especially in Japan. Passive heat retention is achieved by enhancing the thermal insulation using microfibres and bulky webs. Active heat generation is achieved, for example, by incorporation of exothermic functions in fibres. Thermotron (also known as Solaro) was the first heat-regenerating conjugate fibre with a core containing zirconium carbide (ZrC). Since ZrC absorbs sunlight (visible and near-infrared radiation) and emits far-infrared radiation, one feels warmer when one puts a jacket made of Thermotron on. Thermocatch W (a sheath-and-core type acrylic fibre from Mitsubishi Rayon), MasonicN (a nylon filament mixed with ceramic micro-particles from Kanebo), and Lonwave (a hollow polyester fibre mixed with ceramic micro-particles from Kuraray) are heat-generating fibres based on the same principle. Cooling fibres Other relatively new technology of interest is cooling fibres by the introduction of water-retaining fibres into the fabric structure. These fibres are sandwiched
between a breathable out fabric, e.g. cotton and Nomex and an inner layer Recent conducting heat and moisture from the body (Stull, 2000). developments in
materials Reactive materials for flame and heat protection These types of materials are designed to provide minimal insulation during normal wear, but maximum insulation when the heat threat impinges (Scott, 1999; Congalton, 1999). The novel treatments can be mentioned as Intumescent treatments – these would normally be in the form of thin, low insulation coatings on a lining fabric: when activated by excessive heat or flame the formulation swells instantly to form an inert insulative char, protecting the wearer. Shaped memory alloys – these are metals which can assume different shapes when the temperature is changed. One wishes to establish a large air gap during the threat phase. This can be achieved by using a coil spring between two fabrics layers which adopts a flat conformation during normal operations, but which rapidly forms an extended helical shape when the heat threat arrives. Thermochromic dyes – these are textile colorants which change colour with temperature. These dyes provide radiant flash protection and reflect a proportion of the incident radiant energy. Biomimetics and fibres The structure and functions of natural biological materials are precise and welldefined. The imitation of living systems, “biomimetics” could make it possible in future to replicate the molecular design and morphology of natural biological materials once their structure and functions are related. Already in many laboratories around the world, R&D work is going on in the field of biomimetic chemistry and fibre formation. A typical example is the development of water and soil repellent fabrics T produced by imitating the surface structure of a lotus leaf. In future interaction of fibre science, fibre technology and biomimetics will constitute an integral part of textile research resulting in composite structures, functional surface structures, high tenacity fibres etc. In 1987 the Technology Prize of the Society of Fiber Science and Technology, Japan, was awarded to the Teijin Co. for its development of fabrics with high water repellency. Super-Microft is one that was designed by emulating the structure of a lotus leaf. Water rolls like mercury from the lotus leaf, whose surface is microscopically rough and covered with a wax-like substance with low surface tension. When water is dropped on to the surface of a lotus leaf; air is trapped in the dents and forms a boundary with water. The contact angle of the water is large, because of the wax-like substance. The apparent contact angle depends on the evenness and roughness of the surface,
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and surface tension. When (i) the surface is reasonably even but with microscopic dents to enlarge the surface area and to trap air, and (ii) the surface tension of fibres is small, then water rolls well on the fabrics. Super-Microft is a highly water-repellent fabric made of polyester fibres, harnessing the waterrepellent mechanisms of lotus leaves.
214 Concluding remarks The driving technology force in material development for protective clothing has been spear-headed by advances in fibres, polymers, chemical technology and fabric/web forming technologies. The technological trends and challenges ahead will be determined by market pull demands, increasing environmental awareness, personal safety and comfort, and performance requirements. The advances in material and technologies should lead to products with soughtafter characteristics, e.g. laminates able to meet multiple functional requirement, coating which can be tailored for specific end-uses, fibres and fibre-blends for demanding applications and sophisticated fibrous structures. References Berber, H. (1995), “Textile Processing of Fibres based on Melamine Resin”, Techtextil Symposium, lecture 2.14, Messe Frankfurt. Bernstein, U. and Thiele, R. (1995), “New Dustproof Textiles from Composite Nonwovens”, Techtextil Symposium, lecture 2.56, Messe Frankfurt. Bontemps, G. (1995), “Schappe Core Yarns for Protection against Heat”, Techtextil Symposium, lecture 2.41, Messe Frankfurt. Cassat, R. and Hoessi, J. (1995), Kermel Tech – A New Fibre for Industrial Applications”, Techtextil Symposium, lecture 2.56, Messe Frankfurt. Congalton, D. (1999), “Thermally Active Clothing Systems using Shape Memory Alloys and Polymers”, Intelligent Textiles Conference, Heriot-Watt University, Sept. Gorashi, H.M. and Stocks, A.I. (1995), “Nomex Omega – a new fibre for active fire protection”, Techtextil Symposium, lecture 2.16, Messe Frankfurt. Jacobs, M.J.N. and Mencke, J.J. (1995), “New Technologies in Gel-Spinning the World’s Strongest Fibres”, Techtextil Symposium, lecture 2.13, Messe Frankfurt. Leitch, P. and Tassinari, T.H. (2000), “Interactive Textiles; New Materials in the New Millennium Part 1”, J. of Industrial Textiles, Vol. 29 No. 3, pp. 173-90 January. Mukhopadhyay, S.K. (1993), “High Performance Fibres”, Textile Progress. Vol. 25, No 3/4, 1993, The Textile Institute. Ott, K. (1995), “Development of Heavy Fire and Heat Protection Suits from Basofil for the BASF Fire Brigade”, Techtextil Symposium, lecture 2.43, Messe Frankfurt. Pause, B. (1995), “Development of Heat and Cold Insulating Membrane Structures with Phase Change Material”, J. of Coated Fabric, Vol. 25 No. 7, pp. 59-68. Pause, B. (1999), “Development of Self-conditioning Sport Shoe with PCM”, Techtextil Symposium, lecture 305, Messe Frankfurt, pp. 22-6. PEN-fibres, (1999), Technical Information, KoSa GmbH & Co. April.
Proceeding AVANTEX Symposium 27–29 Nov. 2000, Messe Frankfurt. Russel, A., Hayashi, S. and Yamada, T. (1999), “The Potential Use of Shape Memory Film in Clothing”, Techtextil Symposium, lecture 302, Messe Frankfurt. Scott, R.A. (1999), “Intumescent Treatments for Flame and Heat Protection”, Intelligent Textiles Conference, Heriot-Watt University, Galashiels, Sept. Shishoo, R., (1988), “Technology for Comfort”, Textile Asia, June. Shishoo, R. (2000), “Global Advances in Technical Fibres and Fibrous Products for Speciality Applications”, Techtextil North American Symposium 2000, Atlanta. March 22-4. Simpson, U. (1995), “New Possibilities through the Making of Protective Clothing for Drakness with Luminescent Fabric Film”, Techtextil Symposium, lecture 2.44, Messe Frankfurt. Spijkers, J.C.W. (1995), “New Application of Sympatex Polyester Membranes in Personal Protection”, Techtextil Symposium, lecture 2.52, Messe Frankfurt. Stull, J.O. (2000), “Cooler Fabrics for Protective Apparel”, Industrial Fabric Products Review, Vol. 76 No 11, 62-8, March. Super High Performance Fiber ZYLON (1998), Technical Information, Toyobo Co. Technical Textiles International (1999), Phase change materials show potential for medical applications, September, 23-6. Technical Textiles International, (1999), “Potential uses of shape memory film in clothing”, October, 17-19. Van Gorp, E.H.M. Van der Loo, L.L.H (1995), “Dyneema Non-wovens for Ballistic Protection”, Techtextil Symposium, lecture 2.53, Messe Frankfurt. Van Zijl, N., Ren, I. and Chiou, M. (1999), “High Comfort Systems with KEVLAR for Protection against Sharp and pointed Weapons”, Techtextil Symposium, New Protective Textiles, lecture 301, Messe Frankfurt.
Recent developments in materials 215
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Theoretical analysis of compression properties of blankets Mari Inoue and Satoshi Kurata Kobe University, Kobe, Japan Keywords Compression, Blankets Abstract We predict the compression properties of blankets from the blanket structure and the fiber bending property. This study applies to the theory developed originally for the compressive deformation of carpets by Kimura, Kawabata and Kawai in 1970 to blankets. As a result, we found that the initial compression properties of Mayor and New Mayor blankets could be predicted by the compression theory.
1. Introduction The main performance factor of blankets was naturally thermal insulation and other utility functions. However, recently blankets are widely used throughout all four seasons, even in summer because the air conditioning units are generally used. In some cases, blankets have a direct contact with human hands and skin, particularly if used without sheets. And therefore, tactile performance of blankets, that is, good handle, now attracts peoples’ attention. Therefore, one of the important components related to the quality of blankets is tactile performance, that is good handle. Niwa et al., (1999, 2001) found that the method derived from the direct correlation of characteristic parameters with subjective THV increased the regression accuracy of handle of blankets. The results showed the effectiveness of including surface, compression, thickness and weight. The surface and compression properties of blankets are supposed to be effected by the mechanical properties of the fiber composing blankets. In this study, we suggest the theory predicting the compression properties of blankets using the fiber bending property and the blanket structure. The theory is based on the compressive deformation theory of carpets developed by Kimura et al. (1970). The theoretical equations are derived on the basis of the thin rod theory on elastica. One side of the structure of mayor and new mayor blankets is similar to the structure of carpets. The objective of this study is to inspect the validity of the theory for predicting the compression property of blankets. International Journal of Clothing Science and Technology, Vol. 14 No. 3/4, 2002, pp. 216-222. q MCB UP Limited, 0955-6222 DOI 10.1108/09556220210437176
We wish to express our sincere thanks to Professor Niwa for her valuable discussions.
2. Theory Figure 1 shows the basic structure model of blankets. A straight fiber is inserted into backing cloth with the inclined angle b of the thread from the perpendicular line to the cloth. Where, h is fiber’s height, that is, thickness of blankets, and L is fiber length. We assumed that fibers are equally arranged in lattice as shown in Figure 1. When the model is compressed, the compressed angle a, that is, the angle between tangential line at the end of fiber and perpendicular line, becomes large as shown in Figure 2. When the fibers of blankets are compressed, two types of deformed shapes of fiber are observed as shown in Figure 3, depending on the initial shape of a fiber, direction of the compressed force, and frictional coefficient between end
Theoretical analysis of compression 217
Figure 1. Structural model
Figure 2. Compression model
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218 Figure 3. Deformed shapes NA:number ratio of A shape, NB:number ratio of B shape, NA þ NB ¼ 1
of fiber and compression plate. When the length is same, the compressed force of B shape is about eight times the force of A shape. In an actual deformation of blankets, both the A and B shapes are simultaneously observed. Therefore, we introduce parameters, NA and NB, to represent the ratio of the two shapes. Typical value of NA obtained by experimental observation is about 0.7. Therefore, we used the value for the calculation. In the case of A shape, the compression force can be derived from the bending property of rigid rod with a fixed end. The basic structure of blankets is shown in Figure 4. A straight fiber is inserted into backing cloth with the inclined angle b of the thread from the perpendicular line to the cloth. The compression property of blankets is derived by the relationship between the compression force of a single fiber induced by the bending deformation of a single fiber and the decrease of the thickness. The theory of elasticity gives the non-linear differential equation (1) EI
du þ P y 2 Rx ¼ 0 ds R ¼ ^mP
EI P ¼ pffiffiffiffiffiffiffiffiffiffiffiffiffiffi L2 1 þ m2
Z
!2 df pffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi 1 þ K 2 sin2 f f0 p 2
!2 rffiffiffiffiffi Z p Z p 2 pffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi 2 EI d w pffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi h¼ 1 þ K 2 sin2 f dw 2 P 1 þ K 2 sin2 f f0 w0
ð1Þ ð2Þ
ð3Þ
ð4Þ
Theoretical analysis of compression 219
Figure 4. Fiber bending model
where, 8 9 b > > > > <sin = 2 21 a ; K ¼ sin > > > : sin 2 > ;
9 8 bþw > > > > <sin = 2 21 ; f ¼ sin > aþw > > > :sin ; 2
w ¼ tan21 ð7mÞ
EI: bending rigidity, P: force, u: angle between tangential line at Q point and perpendicular line, a: value of u at 0 point, s: arc length from 0 point, R: force of horizontal direction (friction), m: frictional coefficient between fiber end and compression plate When bending stiffness of fiber EI, Fiber length L, f which is calculated by inclined angle b and compression angle a are given, compression force P is calculated by equation (3). When the calculated P value and compression angle a are given to equation (4), the thickness h is calculated. Therefore, the relationship between the compression force P of a single fiber and the thickness h, that is, the compression property of blankets is derived. The compression force of blankets, P(gf/cm2) is derived by force of a single fiber, P(gf) times n, number of fibers per 1 cm2. (The theoretical equations are derived on the basis of the thin rod theory on elastica. In the case of carpets, the thin rod was yarn. On the other hand, in this study, the rod is a single fiber. The bending properties of a single fiber composing of blankets are used.)
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Figure 5. Bending property of fiber composed of N-1 blanket
3. Experimental results and discussion The basic structural parameters are fiber length L, inclined angle b, number of fibers per unit N, diameter of fiber Dc. These parameters were obtained by experimental observation. Fiber bending stiffness EI was experimentally measured. Frictional coefficient, m value was used in literature in this study. We used the m value, 0.05 for the calculation. The structural parameters and the fiber bending properties applied to the calculation are obtained by measurement of the structure of the test-blankets specimen and the properties of single fibers taken out of blankets. The bending stiffness EI was estimated experimentally by measuring the bending properties of twenty single fibers taken out of blankets, which was carried out by using KES-F2 bending tester. Figure 5 shows example of bending property, that is, the relationship between curvature and bending moment. The bending stiffness is obtained by this slope. In order to examine the ability of the theory to make predictions, compression deformation experiment on a specimen of blankets was carried out to compare the experimental results and the theoretical prediction. The structural parameters and the fiber bending properties applied to the calculation are obtained by measurement of the structure of the test-blankets specimen and the properties of single fibers taken out of the blankets. The bending stiffness used by the calculation was estimated experimentally by measuring the bending properties of sixty single fibers, which was carried out by using KES-F2 bending tester. The basic parameters used by the calculation are shown in Table I. The compression experiment was carried out by using a modified KES-3 version of the Handy compression tester, with a 25 cm2 compression plate. The structures of samples used in this study are mayor and new mayor blankets as shown in Figures 6 and 7. The blankets are composed of both face and back
sides. We calculated each side by the theory and got the sum of both sides as a result of the sample blankets’ compression property. Figures 6 and 7 show the results of the theoretical calculation and the experiment, where the theoretical prediction curves are shown by broken lines
No.
Structure
Thickness (mm)
N-1 N-4
Mayor New Mayor
17.6 8.5
face back
Fiber diameter (mm)
Number of fiber (1/cm2)
Fiber length (cm)
Angle b (degree)
23.6 12.9
4096 4725
1.19 0.75 0.56
46.0 40.1 28.9
Bending stiffness (g.cm2) 8.11£102 5 6.49 £ 102 5
Theoretical analysis of compression 221 Table I. Basic structural parameters of blanket specimen
Figure 6. Initial compression property of mayor blanket
Figure 7. Initial compression property of new mayor blanket
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and the experimental curves by solid lines. Good agreement between them can be observed. As a result, we found that the initial compression properties of blankets were predicted by the compression theory applying to the theory for carpet, which was presented by Kimura et al. (1970). In summary, we found that the initial compression properties of mayor and new mayor blankets could be predicted by the compression theory with the structural model and fiber bending property. References Kimura, K., Kawabata, S. and Kawai, H. (1970), “Journal of the Textile Machinery Society of Japan”, Vol. 23 No. 4. Niwa, M., Inoue, M. and Kawabata, S. (1999), “The objective evaluation of blanket hand and durability –- A preliminary investigation”, International Journal of Clothing Science and Technology, Vol. 11 No. 2/3, pp. 90-104. Niwa, M., Inoue, M. and Kawabata, S. (2001), “Objective evaluation of the handle of blankets”, Textile Research Journal, Vol. 71 No. 8 in press.
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Analytical woven fabric mechanics G.A.V. Leaf Leeds, UK
Analytical woven fabric mechanics 223
Keywords Textiles, Woven fabrics, Mechanics Abstract The paper briefly reviews the results of previously published analytical studies of the mechanics of plain woven fabrics, and shows how these can be used to determine how the various properties (extension, bending, shear) are related to each other.
Introduction The mechanical properties of textile products are virtually unique among engineering structures, and arise not only from the properties of the fibres used in the construction but are also due to the internal structure of the fibrous assemblies. Consequently there has been, for many years, considerable interest in the study of such structures, and particularly of the interaction between the properties of the components (fibres, yarns etc.) and the details of the structures into which the components are formed. Particular attention has been paid to the analysis of woven fabrics, and various approaches have been adopted. Some of the methods developed are quite general and have led to rather powerful and elegant methods for analysing the behaviour of woven fabrics under large deformations (Hearle and Stephenson, 1978; Postle and de Jong), but they tend to require the development of computer software to implement them. However, there is a class of simpler approaches that are more restricted in their application which, by limiting their objective to the study of small deformations, results in a series of closed form solutions that have an aesthetic appeal and unity which, perhaps, makes them more suitable for teaching purposes than the more general approaches mentioned earlier. This paper is concerned with these small deformation solutions. The mechanical properties studied are fabric extension, measured by moduli E1 and E2 (we shall use the usual convention with suffixes 1 and 2 to refer warp and weft directions, respectively); fabric bending resistance, measured by flexural rigidities B1 and B2; and fabric shear, measured by a shear modulus G. We are concerned with how these fabric mechanical properties are related to the properties of the yarns from which the fabrics are made and to the structural parameters of the fabric, its thread spacings, yarn crimps, etc. The study of woven fabric geometry was pioneered by Peirce (1937), and many of the later anaylses have been based on his models. It is appropriate,
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therefore, to begin by describing Peirce’s basic model and, in doing so, introduce the notation we shall use. Peirce’s models In order to simplify his models Peirce began by assuming that: (1) the yarns are perfectly flexible, i.e. their flexural rigidity¼0; (2) the yarns have circular cross-sections; (3) the yarns are incompressible; (4) the yarns are inextensible. Of course, none of these assumptions are strictly justified but they do simplify the analysis and lead to some useful relations among the fabric parameters. The resulting model is shown in Figure 1. The yarn path, exemplified by the warp path ABCD in Figure 1, consists of straight lines and arcs of circles and is of length l1. Other dimensions are marked on the diagram. Peirce defined yarn crimp (c ) by the equations l 1 ¼ p2 ð1 þ c1 Þ;
l 2 ¼ p1 ð1 þ c2 Þ;
ð1Þ
and was able to show that 1=2
h1 < 1:33 p2 c1 ;
1=2
h2 < 1:33 p1 c2 ;
ð2Þ
and that: h1 þ h2 ¼ d1 þ d2 ¼ D:
ð3Þ
He also deduced that: 1=2
u1 < 1:88 c1 ;
1=2
u2 < 1:88 c2 ;
ð4Þ
when the angles are measured in radians. An important feature of the model, as we shall see, are the “contact lengths”, AB and CD in Figure 1. These are each of length Du1/2 in the model, and the length of the straight section BC is therefore ðl 1 2 Du1 Þ: In a real fabric, the lengths of the contact regions are likely to be different, because of the yarn rigidity, so we shall assume them to be of length k1Du1/2, and that the length of the straight section is l 1 2 k1 Du1 : ð5Þ The mechanical equations The required equations relating the geometrical parameters are defined earlier, the yarn bending rigidities b1 and b2, and the fabric moduli were derived by
Leaf and Kandil (1980); Leaf and Sheta (1984) and Leaf et al. (1993). The analyses assume that only the straight sections bend when the fabrics are deformed. Using relatively straight-forward and well-known analytical methods the equations obtained were as follows: 12p2 b1 b2 ðl 1 2 k1 Du1 Þ3 cos2 u1 E1 ¼ ; ð6Þ 1þ p1 ðl 1 2 k1 Du1 Þ3 sin2 u1 b1 ðl 2 2 k2 Du2 Þ3 cos2 u2 12p1 b2 b1 ðl 2 2 k2 Du2 Þ3 cos2 u2 E2 ¼ ; 1þ p2 ðl 2 2 k2 Du2 Þ3 sin2 u2 b2 ðl 1 2 k1 Du1 Þ3 cos2 u1
225
ð7Þ
B1 ¼
b1 p2 ; p1 ðl 1 2 k1 Du1 Þ
ð8Þ
B2 ¼
b2 p1 ; p2 ðl 2 2 k2 Du2 Þ
ð9Þ
p1 ðl 1 2 k1 Du1 Þ3 p2 ðl 2 2 k2 Du2 Þ3 G ¼ 12 þ p2 b1 p 1 b2
Analytical woven fabric mechanics
21 :
ð10Þ
These equations have been shown to be in reasonable accord with experimental data, provided the values of k1 and k2 are chosen appropriately. Unfortunately, the values of the mechanical moduli are rather sensitive to the choice of the k values, and this is something that needs to be investigated further, but the form of the equations can tell us about how fabrics behave and what will happen to their properties if we change one or more of the fabric parameters. For example, consider equation (8). Differentiating this with respect to p1, one gets: b1 p2 dB1 ¼ 2 2 dp1 : p1 ðl 1 2 k1 Du1
Figure 1.
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Note that, in performing this differentiation, one has to make sure that u1 is not a function of p1 and it is quite easy to see from equations (1) and (4). A particular fabric might have the values l 1 ¼ 0:700 mm; p1 ¼ 0:485 mm; p2 ¼ 0:588 mm; b1 ¼ 5:62 mNmm2 ; D ¼ 0:500 mm; u1 ¼ 0:821 radians; B1 ¼ 19:6 mNmm2 =mm; k1 ¼ 0:8 (say). We then find that: dB1 ¼ 238:3 dp1 : Thus, if we want to change B1 from its current value of 19.6 mNmm to, say, 19.0 mNmm by changing only the warp spacing, we need to change p1 by dp1 ¼ 20:6=ð238:3Þ ¼ 0:016; i.e. from 0.485 to 0.501 mm. This kind of calculation gives a student a “feel” for the orders of magnitude involved. Relations between mechanical properties Of course, if we change B1 in the way envisaged earlier, we shall also change other properties of the fabric, and the equations allow us to estimate the properties of the new fabric. In fact, they allow us to investigate the connections among the various mechanical moduli. For example, eliminating b1 and b2 from equations (8), (9) and (10) yields: 12 ðl 1 2 k1 Du1 Þ2 ðl 2 2 k2 Du2 Þ2 þ ¼ G B1 B2
ð11Þ
This is particularly an interesting equation. So far as I am aware, we do not have a simple method to estimate experimentally the shear modulus of a fabric. The methods used by Treloar (1965) and by the KES equipment can be criticised on the grounds that they do not produce in the test specimen a uniform stress distribution of the kind envisaged in the definition of shear. But the KES equipment, for example, does allow us to make reasonable estimates of B1 and B2. Does equation (11) form the basis of a method for estimating the real shear modulus of a plain-woven fabric? Leaf and Sheta (1984) attempted to estimate, via a rather round-about route, the values of G for a series of fabrics produced by Kandil (1981), who measured all the quantities on the right-hand side of the equation (11). I have compared the values estimated experimentally by Leaf and Sheta (1984) with those calculated using equation (11). The result is shown in Figure 2. The agreement is quite good, using a value of k ¼ k1 ¼ k2 ¼ 0:8; suggesting that further investigation might be fruitful. Of course, the method is limited in its application to plain woven fabrics but may be useful, especially for teaching purposes.
Analytical woven fabric mechanics 227
Figure 2.
Eliminating b among equations (6), (8) and (9) yields a relation between E1 and B1 and B2 of the form E1 ¼
12{B1 p21 ðl 2 2 k2 Du2 Þ2 cos2 u2 þ B2 p22 ðl 1 2 k1 Du1 Þ2 cos2 u1 } ; ... p21 ðl 1 2 k1 Du1 Þ2 ðl 2 2 k2 Du2 Þ2 sin2 u1 sin2 u2
ð12Þ
showing that E1 can be regarded as a kind of weighted mean of B1 and B2. This relation was tested using Kandil’s (1981) data but when k ¼ 0:8 is used the agreement with experimental values is not too good, equation (12) tending to over-estimate the experimentally determined values, but the correct trend is exhibited in Figure 3. Yet another form of relation involving the Es and the Bs can be deduced. This is: E 1 ðl 1 2 k1 Du1 Þ2 sin2 u1 E 2 ðl 2 2 k2 Du2 Þ2 sin2 u2 21 2 1 ¼ 1: ð13Þ 12B1 12B2 The product on the left hand side is plotted in Figure 4, using k ¼ 0:8; from which it can be seen that the product tends to be less than 1. There is little doubt that the product is rather sensitive to the values of k used but, once again, there is sufficient evidence to suggest that the equations at least anticipate the correct trends. The fact that such relationships occur among the fabric mechanical properties may have other consequences. Many fabric characteristics (e.g. handle, comfort) are obviously influenced by the mechanical properties of the fabrics. In such cases, we have little or no
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Figure 3.
idea of what form these relationships take and often, in these circumstances, recourse is done to statistical linear regression techniques. If the “independent” variables (i.e. the mechanical properties) in such investigations are not truly independent it is well-known that problems arise in estimating the coefficients in the linear regression. The solution would seem to take into account the mechanical relations we have discussed when setting up the statistical model. Conclusions I hope I have said enough to justify the claim that the kind of approach described in this paper is worthy of consideration, at least for a place in teaching of textiles. I find an intellectual satisfaction from such closed-form
Figure 4.
solutions as these, and get a “feel” for the topic that I, personally, do not get from the more general methods. Whether the simpler approach can be extended to more complex structures, as the general methods can, is very doubtful, and there are obvious limitations to the application of the results to practical problems, though I would not rule them out as a first guide in the engineering design of fabrics with specific mechanical properties (Chen and Leaf, 2000). References Chen, X. and Leaf, G.A.V. (2000), Text. Res. J., Vol. 70, p. 437. Hearle, J.W.S. and Stephenson, W.J. (1978), J. Text. Inst., Vol. 69, p. 81. Kandil, K.H. (1981) PhD Thesis, Univ. of Leeds. Leaf, G.A.V. and Kandil, K.H. (1980), J. Text. Inst., Vol. 71, p. 1. Leaf, G.A.V. and Sheta, A.M.F. (1984), J. Text. Inst., Vol. 75, p. 157. Leaf, G.A.V., Chen, Y. and Chen, X. (1993), J. Text. Inst., Vol. 84, p. 419. Peirce, F.T. (1937), J. Text. Inst., Vol. 28, p. T45. Postle, R. and de Jong, S. Treloar, L.R.G. (1965), J. Text. Inst., Vol. 56, p. T533.
Analytical woven fabric mechanics 229
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Objective hand measurement of nonwovens used for top sheet of disposable diapers Hiroko Yokura Shiga University, Japan
Masako Niwa Nara Women’s University, Nara, Japan Keywords Fabric, Clothing Abstract The objective hand evaluation of the top sheet materials used for disposable diapers has been investigated, with consideration given to aspects of both dermatitis and comfort. The objective hand evaluation system for men’s suiting has been applied to assess the hand of top sheet nonwovens. The subjective hand of the top sheet nonwovens, separated from the disposable diaper product, was assessed by female students. It became clear that the hand of the top sheet nonwovens could be predicted by the equation developed for men’s suiting, for which the calculated error was within the range of the standard deviation of the subjective hand value of each product. The correlations between the hand quality of the diaper and the mechanical properties of its top sheet nonwoven were also examined. The diapers with high total hand value (THV ) of their top sheet nonwovens were estimated to have good hand under both dry and wet conditions.
International Journal of Clothing Science and Technology, Vol. 14 No. 3/4, 2002, pp. 230-237. q MCB UP Limited, 0955-6222 DOI 10.1108/09556220210437194
1. Introduction The performance of disposable diapers in the personal care market is improving rapidly. The hand (softness and smoothness) of diapers is considered to be related to both diaper dermatitis and wearing comfort. In our previous study, we investigated the objective hand evaluation of disposable diapers (Yokura and Niwa, 2000a), and clarified the properties of the diapers estimated to have good hand under both dry and wet conditions (Yokura and Niwa, 2000b). Dry diapers with small values of the mean deviation of the coefficient of friction (MMU ) and surface roughness (SMD ), and a large value of compressional resilience (RC ), and containing a large quantity of absorbent material are estimated to have good hand under both dry and wet conditions (Yokura and and Niwa, 2000b). Among these properties, the surface property of the diaper is considered to be influenced by the mechanical and surface properties of its top sheet fabrics. A method for the objective measurement of the fabric hand of men’s suiting has been developed (Kawabata and Niwa, 1996; Kawabata, 1980). This objective hand evaluation system has been applied to the objective evaluation We wish to express our thanks to Ms. Tomoko Kashima of Nara Women’s University for her technical assistance.
of a group of nonwovens which are used for materials near human skin (Kawabata et al., 1994). It was reported that the equation for predicting the hand of men’s suiting was applicable to the hand of nonwovens (Kawabata et al., 1994). This result proved the possibility of common criteria comprising “good feel” existing for all human interactive materials (Kawabata et al., 1994). In this study, we have extended our investigation to the objective hand evaluation of the top sheet materials of disposable diapers. We investigate the relationship between the hand quality of diapers and the mechanical and surface properties of their top sheet fabrics, with the goal of obtaining basic data for use in the design of high-quality products. 2. Experiment 2.1 Sample preparation Sixty nine commercially produced nonwovens for sanitary and medical uses were collected from 1995 to 1997. These samples were made up of 29 nonwoven fabrics used for diapers and underwear, and 40 top sheet fabrics separated from commercially produced disposable diapers. These samples were mostly popular spunbondeds. The fibers in these top sheet nonwovens were mainly polypropylene. 2.2 Objective hand evaluation The objective hand evaluation system of men’s suiting has been applied to the objective evaluation of a group of nonwovens which are used for materials near human skin (Kawabata et al., 1994). Mechanical parameters measured by the KES system are converted into the hand values of three primary hands by using the same constant coefficients as the Equation KN101W series (Kawabata and Niwa, 1996), with modification such that each of the mechanical parameters which is substituted into these equations is normalized by using the respective mean value and standard deviation of the top sheet nonwoven population ðn ¼ 59Þ shown in Table I as follows xi ¼ ðX i 2 mi Þ=si
ð1Þ
where xi : ith normalized mechanical parameter, X i : ith parameter, mi : the top sheet population mean of X i , and si : the standard deviation of X i . The primary hand Yj is obtained as follows 16 X C ij · xi ð2Þ Y j ¼ C 0j þ i¼1
where Y1, Y2, Y3 are the hand values of KOSHI, NUMERI and FUKURAMI, respectively, C0j and Cij are the constant coefficients of the KN101W series (Kawabata and Niwa, 1996) shown in Appendix Table AI.
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Table I. The mean value and standard deviation of the top sheet nonwoven population ðn ¼ 59Þ
Mechanical parameter LT logWT RT logB log2HB logG log2HG log2HG5 LC logWC RC MIU logMMD logSMD logT logW
Mean value mi
Standard deviation si
0.8243 0.0474 58.369 2 1.6356 2 1.5985 0.9411 2 0.0414 2 0.0414 0.7181 2 1.0598 58.924 0.2824 2 1.4095 0.5943 2 0.2206 0.3692
0.0817 0.2902 7.847 0.2064 0.2634 0.2064 0.4219 0.4219 0.0827 0.3719 6.816 0.0618 0.0784 0.0822 0.2410 0.0768
The mechanical and surface parameters of the top sheet nonwovens were measured by the KES system under the conditions for nonwovens (Kawabata et al., 1994). The measuring condition for the mechanical parameters of these nonwovens was changed from the KES standard condition (Kawabata and Niwa, 1996) to some properties as shown in Table II. In the case of nonwovens, we used a single wire sensor for surface friction (Kawabata et al., 1994). The total hand values (THV ) of top sheet fabrics were derived by using both the men’s suiting equation KN301W and the nonwovens equation KN5LNW (Kawabata and Niwa, 1996)
Property
Table II. The new measuring condition for the mechanical and surface parameters of nonwoven fabrics (Kawabata et al., 1994)
Tensile The maximum load Shearing The maximum shear angle Measurement of G Measurement of 2HG Measurement of 2HG5 Compression The maximum pressure Surface The contact force Measurement of MIU, MMD and SMD
Unit 50 gf/cm 0.48 Between 0 and 0.48 of shear angle At 0.28 of shear angle Not measured 10 gf/cm2 10 gf Use a single wire sensor
THV col ¼ C 0 þ
3 X
ð3Þ
Zk
Objective hand measurement
k¼1
where Zk represents the contribution of the primary hand Yk to THV, and can be calculated by equation (4) Z k ¼ C k1 ðY k 2 M k1 Þ=sk1 þ C k2 ðY 2k 2 M k2 Þ=sk2
233
ð4Þ
where C0, Ck1, Ck2: constant coefficients, Yk: the hand value of ith primary hand, Mk1: population mean value of the kth primary hand value Yk for top sheet materials, sk1: population standard deviation of kth primary hand value Yk, Mk2: population mean value of the square of the kth primary hand value Yk, si2: population standard deviation of the square of the kth primary hand value Yk. The constant coefficients are shown in Appendix Table AII.
2.3 Subjective evaluation of hand The hand of 40 top sheet nonwovens, separated from commercially produced diapers, were assessed by 25 female students. They were asked only to judge whether the hand was good or poor, based on the sensation felt from contact with the fabrics. They evaluated sample quality by referring to the standard THV samples for nonwoven fabrics (Kawabata et al., 1994), using a scale from one (poor) to five (excellent). The standard samples were prepared under controlled conditions using fibers of different denier (Kawabata et al., 1994). The mean score of the subjective hand assessments was used as the subjective total hand value (THVsub-top ) of the top sheet materials. In our previous study, the subjective hand of 40 diapers was assessed by mothers and female students (Yokura and Niwa, 2000b). We have obtained the subjective hand value THVsub-diaper of these diapers. The results of the subjective hand assessments of dry diapers are summarized in Table III.
Top sheet fabrics Sample group Number of samples Number of judges R SD
– 40 25 0.59 0.92
Diapers I 26 26 0.54 1.05
II 20 22 0.60 0.85
Notes: R: the mean value of correlation coefficients between individuals and the THVsub within groups; SD: the mean values of the standard deviation on the THVsub of each product.
Table III. Subjective hand assessments
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Table IV. Correlation coefficients between the calculated hand factors of top sheet fabrics and subjective THVsub of the top sheet fabrics and diapers
Figure 1. Relationship between the subjective THVsub-top and the predicted THV(KN301W) of top sheet nonwovens
3. Results and discussion 3.1 Objective hand evaluation of top sheet nonwovens The results of the subjective hand assessments of top sheet nonwovens are summarized in Table III. The correlation coefficients between the calculated hand factors (the primary hands and THV ) of top sheet nonwovens and subjective THVsub of the top sheet nonwovens are shown in Table IV. There is high correlation between NUMERI and THVsub-top. This result was same for other types of nonwoven fabrics (Kawabata et al., 1994). In the case of THVsub of top sheet nonwoven fabrics, NUMERI (smoothness) is the most important property for the primary hand quality. Figure 1 shows the relationship between the THVsub-top and the predicted THV(KN301W) of top sheet nonwovens. The correlation coefficient was 0.69, and the prediction error RMS was 0.50. The mean value of the standard deviation SD on the THVsub-top of each fabric is also plotted in Figure 1. It is clear that the hand of the top sheet materials can be predicted by the equation developed for men’s suiting, for which the
Hand values
THVsub-top
THVsub-diaper
KOSHI NUMERI FUKURAMI THV(301W)
2 0.065 0.741** 0.688** 0.690** ðRMS ¼ 0:50Þ 0.501**
0.094 0.569** 0.470** 0.554** ðRMS ¼ 0:63Þ 0.247
THV(5LNW) **
1 percent significance level, r . 0:403 ðn ¼ 40Þ.
calculated error is within the range of the standard deviation SD on THVsubtop of each fabric listed in Table III. This agreement proves the similarity between the THV criteria of men’s suiting and that for nonwoven fabrics. 3.2 Hand quality of diapers and mechanical properties of its top sheet nonwovens Table III also shows the results of the subjective hand assessments for dry diapers (Yokura and Niwa, 2000b). Agreement between individual judges was lower for dry diapers than for top sheet nonwoven fabrics. It seems that assessing diapers is relatively difficult compared to assessing nonwoven fabrics, because disposable diapers have a more complex structure than nonwovens. The correlation coefficients between the calculated hand factors of top sheet nonwovens and subjective THVsub-diaper of the diapers are shown in Table IV. The THVsub-diaper was correlated with the THV(KN301W) and smoothness (NUMERI ) of their top sheet fabrics. This result proves the possibility of designing the hand quality of dry diapers using the mechanical parameters of their top sheet fabrics. The diapers with high THV of top sheet nonwovens were estimated to have good hand. The correlation coefficients between the THVsub-diaper of diapers and each of the mechanical parameters of their top sheet nonwovens are shown in Table V. We saw the highest correlation in relation to the surface parameter, MMD. The lower MMD increases smoothness and accordingly increases THV. Dry diapers with small MMD and SMD values of their top sheet fabrics are estimated to have good hand under both dry and wet conditions.
Parameters Tensile Bending Shear Comp. Surface Thickness Weight **
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r LT WT RT B 2HB G 2HG LC WC RC MIU2 MMD2 SMD2 T W
1 percent significance level, r . 0:403 ðn ¼ 40Þ.
0.005 20.049 0.105 0.241 0.267 20.317 20.222 0.318 0.261 0.421** 20.443** 20.617** 20.516** 0.240 20.140
Table V. Correlation coefficients r between the subjective THVsubdiaper and each of the mechanical parameters of the top sheet fabrics
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4. Conclusions We have investigated the objective hand evaluation of the top sheet materials used for disposable diapers. The objective hand evaluation system of men’s suiting has been applied to assess the hand of top sheet nonwovens. Primary hand values for top sheet nonwovens are obtained using the same equation as the men’s suiting equations, KN101W series, with minor modifications. Each of the mechanical parameters which are substituted into these equations are normalized by using the respective mean value and standard deviation of the top sheet nonwoven population. Then the three primary hand values are substituted into the THV equation KN301W for men’s suiting to derive the THV of the top sheet nonwovens. It became clear that the hand of the top sheet nonwovens could be predicted by the equation developed for men’s suiting, for which the calculated error was within the range of the standard deviation of the subjective hand value of each product. The correlations between the hand quality of a diaper and the mechanical properties of its top sheet nonwoven were also examined. The diapers with high THV of their top sheet nonwovens were estimated to have good hand under both dry and wet conditions. References Kawabata, S. (1980), The Standardization and Analysis of Hand Evaluation, 2nd ed., The Textile Machinery Society of Japan. Kawabata, S. and Niwa, M. (1996), “Chapter 10, Objective Measurement of Fabric Hand”, Modern Textile Characterization Methods, edited by Mastura Raheel, Marcel Deckker, pp. 329–354. Kawabata, S., Niwa, M. and Wang, F. (1994), “Objective hand measurement of nonwoven fabrics Part I: development of equations”, Text. Res. J., Vol. 64 No. 10, pp. 597-610. Yokura, H. and Niwa, M. (2000a), “Objective hand measurement of materials used for disposable diapers”, Int. J. Clothing Sci. Technol., Vol. 12 No. 3, pp. 184-92. Yokura, H. and Niwa, M. (2000b), “Changes in disposable diaper properties caused by wetting”, Text. Res. J., Vol. 70 No. 2, pp. 135-42.
(The appendix follows overleaf.)
Appendix NUMERI (smoothness) Mechanical parameters
4.7533
Tensile
LT logWT RT logB log2HB logG log2HG log2HG5 LC logWC RC MIU logMMD logSMD logT logW
Bending Shear Comp. Surface Thickness Weight
20.0686 0.0735 20.1619 20.1658 0.1083 20.0263 0.0667 20.3702 20.1703 0.5278 0.0972 20.1539 20.9270 20.3031 20.1358 20.0122
KOSHI (stiffness) C0 5.7093 Ci
FUKURAMI (fullness)
2 0.0317 2 0.1345 0.0676 0.8459 2 0.2104 0.4268 2 0.0793 0.0625 0.0073 2 0.0646 2 0.0041 2 0.0254 0.0307 0.0009 2 0.1714 0.2232
20.1558 0.2241 20.0897 20.0337 0.0848 0.0960 20.0538 20.0657 20.2042 0.8845 0.1879 20.0569 20.5964 20.1702 0.0837 20.1810
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4.9799
237
(1) k
Yk
Ck1
Ck2
Mk1
Mk2
sk1
sk2
1 2 3
NUMERI KOSHI FUKURAMI
2 0.1887 0.6750 0.9312
0.8041 2 0.5341 2 0.7703
4.754 5.709 4.980
25.03 33.90 26.97
1.5594 1.1434 1.4741
15.562 12.113 15.234
(2) k 1 2 3
NUMERI KOSHI FUKURAMI
2 0.0652 2 1.4884 0.4037
0.5977 0.9482 2 0.5028
4.753 5.710 4.979
24.96 34.68 27.41
1.5371 1.4424 1.6187
13.899 17.849 15.225
Table AI. Equations converting mechanical parameter into HV of primary hand (KN101W series) for men’s winter suiting
Table AII. (1) The suiting THV equation parameters (KN301W ) for men’s winter suiting, where C 0 ¼ 3:1466. (2) The nonwoven fabric THV equation parameters (KN5LNW ) for nonwoven fabric, where C 0 ¼ 2:7525
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The importance of clothing science and prospects for the future Masako Niwa Nara Women’s University, Nara, Japan Keywords Clothing, Fabrics, Clothing industry Abstract This paper outlines the history of clothing and modern textile production, from manual systems to modern line-production systems, and notes that this has been affected by the mechanical properties of fabrics. It also focuses on the roles of textile scientists and the clothing industry to meet the needs of society.
1. Introduction Clothing is one item with which humans most closely interact. Thousands of years ago, humans first took textile fibers in hand and began producing clothing. Textiles made of natural fibers were in continuous use for hundreds of years as materials that appeal to human sensibilities. Their history dates back as far as 4000 BC, and these textiles satisfied the original need for decorative beauty as well as functions such as preserving the balance between body heat and the outside environment and protecting from injuries. In addition to these original functions of fabrics, material performance was achieved by harmony of “touch” with a beautiful appearance. They contributed to the richness of the human heart. The qualities of fabrics that relate to the dialog between people and fabrics came to be called “fabric hand”. In the millennia since then, we have learned through experience to distinguish the quality of materials.
International Journal of Clothing Science and Technology, Vol. 14 No. 3/4, 2002, pp. 238-246. q MCB UP Limited, 0955-6222 DOI 10.1108/09556220210437202
2. History of modern textile production In modern times, apparel manufacture has become industrialized. The transition from manual work to mechanized manufacturing, as well as the development of high-speed automated manufacturing, gave birth to the clothing and textile industries. However, the current rapid advancements are primarily in the area of efficient manufacturing technology, and the quality of the manufactured product has not necessarily been high. This is due to the slow advancements of the objective evaluation methods and methods for product design for aesthetic performance.
The performance of fabrics as clothing materia1s must be considered from several viewpoints. Roughly, it may be divided into two categories. First is the utility of a fabric as clothing material, indicated by its friction resistance during wear and so on. Second is the comfort and aesthetic performance aspect of a fabric, which may be more directly related to genuine high quality as clothing materials. The first type of performance is important, and excellent research work concerning this kind of fabric performance has been carried out, with standards having been established in many countries. On the other hand, the second category of performance is probably equally essential and important in clothing material, because consumers pursue better quality in this aspect of performance, provided the first category of performance is satisfied to some extent. Judgment of fabric hand has long been used by textile manufacturers and consumers as a method of evaluating fabric performance from the mechanical – comfort viewpoint. A new thrust occurred when Peirce (1930) initiated research on fabric mechanical properties and directed attention to the control of fabric hand by engineering means. Much research on textile mechanics has been carried out since Peirce’s time. The basis of motivation of this research is certainly in the improvement and control of performance by engineering means. As a result of the accumulation of a great deal of basic research work by many researchers in the fabric-mechanics field, we now have the possibility of realizing the design and control of the second fabric-performance aspect by engineering means. This research has concentrated on the objective methods of evaluating hand that have recently been developed. In addition, as a result the change from the craftsman’s manual system of clothing production to modern line-production systems, the fabric-property requirements for achieving better making-up on the garment production line are becoming more important in industry. Mechanical properties are critically related to this need. This is the third performance aspect of the fabric as clothing material. Lindberg et al.,’s (1960) forecast about making-up in garment production is now becoming effective. In 1978, Prof. Kawabata and I initiated a cooperative effort with apparel engineers and have since improved the prediction equations for fabric performance related to the making-up of garments (Kawabata and Niwa, 1989). 3. Art and technology In the history of polymer science, we can see that polymer materials progressed through three stages: first, strength and durability; second, functionality; and third, conformity to human sensibilities. At the end of the 20th century, we have experienced the change from the first to the second, which relied on technology, and are now facing the challenge of the third, which will rely on art as well.
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Over the millennia devices for more effective textile production have been developed, and they have brought the beauty of fabrics to a kind of art. That is, for a long time art and technology were combined to deepen the relationship between “materials” and “humankind”. The beauty of clothing and the quality of “fabric hand” just represent these facts. Even in functional items for daily life, as opposed to items of art like paintings or music, people have always sought beauty. Beauty in functional items is not merely a matter of superficial appearance, but rather a direct response to humankind’s yearning for beauty. However, in the industrialized world, the arts have come to be considered the opposite of technology, particularly high-level technology. Technology has been prone to estrangement from humanity, and it cannot be denied that, watching the progress of polymer science, it has been hard to sense human warmth and beauty. For example, textiles are used in direct contact with people, but despite their essential nature as materials that conform to human sensibilities, modern science has avoided tackling this directly and in earnest. The third phase of development will see the fusion of art and science, and we must aim to create polymer materials that appeal to the human heart (Niwa, 1998a). Recent scientific technology has ignored the dialog with humankind called “fabric hand” in pursuit of functionality and practicality. For example, “fabric hand” was thought of as a typical example of an unscientific idea having a lessthan-reliable background, and as such was not even the subject of research. There have been a variety of developments in synthetic polymer science since the 1970s, each heralded with pride as the fiber that will dominate the future. From the appearance of “Go-sen” (synthetic fibers) to “Shin Go-sen” (new synthetic fibers) to “Shin-shin Go-sen” (post-new synthetic fibers), the development of new materials continued. But have these new fibers been accepted by humankind as favorable materials? From 1970, centred in Japan, the development of a standardization and numerization system for determining “fabric hand” progressed, and from 1980 an objective assessment system was realized and has come to be used throughout the world (Kawabata, 1980). At the interface of polymer materials and humankind there commonly exists the materials “hand” as well as their beauty. Recent research has revealed that the objective evaluation system for “fabric hand” can also be applied to other materials touched by people (Kawabata et al., 1994), including blankets (Niwa et al., 2001), futons, and other bedding; disposable diapers (Yokura and Niwa, 1997) and other sanitary goods; wrapping materials; leather goods; paper; and even the steering wheels of cars. Clothing materials by itself gives birth to beauty. The study of textile materials used in the human environment must break free of the research that leads to human alienation, even if it leads to the creation of something new, and leave behind the era of superficial beauty for performance’s sake. In the evolution of a new era, should not we in the study of textiles strive for greater
affinity to humanity and continue to seek materials that have a deeper appeal to people’s heart?
4. The role of female scientists and researchers Most textiles are used in the human environment, either as clothing or in interior goods. In research projects, thoroughly taking into account preparations for the human environment for all ages, from newborn to old age; protection of the environment; effective utilization of resources; and final treatments for disposal, it is necessary to incorporate the viewpoints of female scientists and researchers who have backgrounds in fundamental and theoretical research works to provide the stimulation to revitalize the textile industry (Niwa, 200). If we look at history, whether that of East or West, we learn that those who rang the warning bells about environmental destruction and who pointed out the importance of environmental problems were mainly women; for example, Rachel Carson (1962), the author of “Silent Spring”, and Theo Colborn et al. (1996), the first author of “Our Stolen Future”, about environmental hormones. It is very important to achieve women’s empowerment, and it is highly expected to be realized in the future. I feel that the industry needs to pay more attention to the women’s perspective. For example, in many studies of clothing for men and women, I often find that men create the clothes for women (Kawabata and Niwa, 1992). The creation of women’s apparel is certainly an area where women should have expertise; other areas include but are not limited to clothing for infants and children, the elderly, and the handicapped. In the “cycle of knowledge” that links universities and the textile industry, and particularly the field of textile manufacturing, female scientists and technicians can be considered as an undeveloped intellectual resource. I hope that their viewpoints will also be incorporated in the above cycle. We must demand concentration on the wisdom and achievement of both men and women in studying the global environment and in the development of science and technology. University research in the fields of science and engineering carries two roles: the creation of the fundamentals of industrial technology as well as the responsibility of cultural roles. Recently, the role of the universities has been brought into question, and it is thought that the major roles of universities are to actively return the results of their research works back to society, and on the other hand to create a new body of knowledge and continue fundamental research that will withstand the current trends. Many kinds of research are permitted to grow in the rich academic soil, and it is believed that creative research development is not possible without good circumstances.
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Figure 1. The ideal fabric concept (Kawabata et al., 1999)
5. The ideal fabric We are now attempting to combine scientific methods with professional skills in the textile mills to establish the engineering techniques needed to produce ideal fabrics for clothing material on the basis of newly developed technology for objective evaluation; and then to find a technical guideline for precision manufacturing of low-cost ideal fabrics. This vertical cooperation is very important and we have never had such technical cooperation before, especially here in Japan. We call this project the “Ideal Fabric Project” (Kawabata et al., 1999). For the objective evaluation of the fabric performance we used three criteria which we have developed: good fabric hand, good garment appearance, and comfort of garment. The ideal fabrics are those which satisfy these three criteria as shown in Figure 1. The objective measurement clearly indicates the direction that must be taken to improve fabrics (Kawabata, 1980). After we obtain some ideal fabrics, tailoring will be tried followed by inspection of suit performance, as well as of consumer response (Kawabata and Niwa, 1989). This method is applicable to other types of fabrics, such as women’s dress fabrics, knitted fabrics, and various end-use fabrics, as we already have criteria for objectively evaluating the quality of these fabrics. The eventual goal of the Ideal Fabric Project is to use engineered design and manufacturing technology to provide consumers with high-quality fabrics at a reasonable price. The engineered manufacturing of high-quality clothing and clothing materials is an absolute necessity for the future of textile industries as shown in Figure 2. The engineered design of fabric quality is a goal of textile technology development (Kawabata et al., 2001). There are four crucial factors. The first and most important is the selection of high-quality fabrics for garment materials, or fabrics with good hand. Secondly, the garment manufacturing of these fabrics requires difficult technical operations, and we must solve these difficulties with advanced technology. Next, the reduction of manufacturing costs must be taken into account when applying modern technology. Finally, automated adjustment of sewing machines to optimum conditions based on the
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Figure 2. Development of the ideal fabrics under the cooperation of university and industry (Kawabata et al., 2001)
information about fabric properties is desirable. From the academic side, we must continue to do more research in the theoretical areas. 6. The future of the clothing science The quality of textile products is a barometer of a civilization; however, one cannot say that what sells must be of the best quality. The essential quality of the final textile product ought to show true harmony with humankind. It is necessary to introduce a consideration of human sensitivity to textile engineering and to construct new textile engineering in which humankind plays a central role. I do not think that a textile industry flattering each consumer age group will contribute to a rich living environment in the 21st century. At the turn of the millennium, we must question the basic expectations of technology. As new technologies can have a great impact on industry and economy, much is expected of technology. Society expects economic results from technology. Ought not the field of textile technology to change its
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Figure 3. The prediction map of textile technology and clothing science in the next 30 years (Kawabata et al., 2001)
direction to concentrate on meeting, through new inventions and discoveries, the most important and essential needs, such as widening our views of the world, creating new cultures, protecting our health, keeping us safe, and raising the quality of our daily lives and welfare? Figure 3 is a forecasting of the structure of textile technology and clothing science in the next thirty years. Textile technology must be reconstructed and we must push more basic research towards more advanced levels. Living standards will continue to rise in the next century. The engineered manufacturing of high-quality clothing and clothing materials is an absolute necessity for the future of textile industries. Fibers are valuable natural resources, even synthetic fibers. We have to use them carefully, so that we do not produce poor fabrics, but only high-quality fabrics of reasonable price. This will also conserve energy. Another new engineering application for textiles is the industrial use of textiles. The use of fibrous composite materials is now rapidly expanding as they become the next generation of materials. Both of these engineering applications depend on the advanced theories of textile mechanics as well. Based on an experiment on the formability of suiting using the KES-F System, there is a similarity between the formability of fabrics in clothing manufacturing and the textile forming for composites manufacturing. Using the mechanical parameters of these industrial fabrics and the prediction equations that have been developed for apparel fabrics, the formability of the industrial fabrics can be examined. In fabric formability for composite forming, it is certainly true that fabric mechanical properties are closely related to formability. Its trial suggests the possibility of the optimum design of fabrics for composite forming with the aid of mechanical property control. More extensive research is necessary to characterize the fabric formability, easy handling, etc. of the textile fabrics for composite forming. Then, these evaluated properties may be easily connected with their mechanical properties for prediction.
In future, clothing scientists must have an accumulated database of fabric’s basic heat, mass transport, and mechanical properties related to: (1) garment comfort,
The importance of clothing science
(2) beautiful garment appearance, and (3) smooth tailorability. Rapid progress in this field was initiated with the spread of a measuring system for fabric’s basic properties. 7. Conclusion Finally, I would like to discuss the role of the textile research and clothing science. It is imperative that the field should not become stagnant if it is to be successful. To that end, I believe that three things are necessary. First, to develop a strong theory, a mission statement, to put a consideration for sensitivity to humankind at the heart of the industry, and to carry out basic research with the goal of fulfilling that mission. In the midst of the rapid changes that occur in our high-level information society, textile research and clothing science, as an academic field backed by a sound theory, would certainly become the power to sustain the industry of this field for a long time. Secondly, to work in harmony with Earth’s environment and to manage resources wisely, from production through disposal of used products. Thirdly, to respect the role of women scientists and researchers, and to incorporate their viewpoints into research. Clothing science must be reconstructed and we must push fundamental research on fiber properties, fabric mechanics, and basic research towards more advanced research levels (Niwa, 1998b). Furthermore, an increase in population and the limited natural resources of the Earth will require the creation of a uniform rational system for the manufacture, consumption, and disposal of clothing. The clothing science field has undertaken this task, and clothing science must work towards the creation of such a system. References Carson, R. (1962), Silent Spring, Houghton Mifflin Co., New York. Colborn, T., Dumanoski, D. and Peterson Myers, J. (1996), Our Stolen Future, A Dutton Book, New York. Kawabata, S. (1980), “The standardization and analysis of hand evaluation“, in, Hand Evaluation and Standardization Committee, 2 Ed., Textile Machinery Society of Japan, Osaka. Kawabata, S. and Niwa, M. (1989), “Fabric performance in clothing and clothing manufacture”, J. Text. Inst., Vol. 80, pp. T19-T50. Kawabata, S. and Niwa, M. (1992), “Objective evaluation of the quality of ladies’ garments”, Int. J. Clothing Sci. Technol., Vol. 4 No. 5, pp. 34-44.
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Kawabata, S., Niwa, M. and Wang, F. (1994), “Objective hand measurement of nonwoven fabrics. Part 1: development of the equations”, Text. Res. J., Vol. 64, pp. 597-610. Kawabata, S., Niwa, M. and Yarnashita, Y. (1999), “A guide line for manufacturing “ideal fabrics””, Int. J. Clothing Sci. Technol., Vol. 11 No. 2&3, pp. 134-40. Kawabata, S., Niwa, M. and Yamashita, Y. (2001), “Recent developments in the evaluation technology of fiber and textiles: toward the engineered design of textile performance”, J. Appl. Polym. Sci., Vol. 82 in press. Lindberg, J., Waesterberg, L. and Svenson, R. (1960), “Wool fabrics as garment construction materials”, J. Text. Inst., Vol. 51, p. T1475. Niwa, M. (1998a), Polymer Science in the Next Century – Art and Technology, KOUBUNSHI/High Polymers, Japan Volume 49 737 pp. Niwa, M. (1998b), “The importance of clothing science and textile education”, SEN’I GAKKAISHI, Vol. 54, pp. P189-94. Niwa, M. (200), “Towards the integration of the viewpoint of female scientists and researchers into the field of textile engineering-related technologies”, SEN’I GAKKAISHI, Vol. 56, pp. P164-5. Niwa, M., Inoue, M. and Kawabata, S. (2001), “Objective evaluation of the handle of blankets”, Text. Res. J., Vol. 71, pp. 701-10. Peirce, F.T. (1930), “The “handle” of cloth as a measurable quality”, J. Text. Inst., Vol. 21, pp. T377-T416. Yokura, H. and Niwa, M. (1997), “Objective hand evaluation on non-woven used for nappies”, Int. J. Clothing Sci. Technol., Vol. 9 No. 2&3, pp. 207-31.
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An introduction to a garment technical drawing system and its DB construction methodology
Garment technical drawing system 247
Young A. Ji and Jae Sang An Korea Institute of Industrial Technology, Chung-Nam, S. Korea
Kyung Seo Lim With Technology Co., Seoul, S. Korea
Dae Hoon Lee Korea Institute of Industrial Technology, Chung-Nam, S. Korea Keywords Garments, Data storage, Apparel, Computer integrated manufacturing Abstract A garment technical drawing system and its database construction methodology is introduced in this paper. The system consists of an application program and a modulized database system. The advantage of this system is that it is possible to construct a garment’s partial technical drawing easily using this database system, and it enables the combination of any part of drawing stored in the database.
Introduction Recently, with innovative advance of computer technologies, the garment manufacturers and related industries have made considerable efforts to construct computer-integrated or computer-controlled system from product concept to consumer’s market place. They have also tried to develop an interface, which is applicable to any system. The technical drawings such as product specification, construction details, and stitch symbols are regarded as a matter of primary means of communication during the apparel manufacturing process for quality control and assurance. Generally, technical drawing is used in the technical file as an easy communication means like a text. It is a very useful means of communication when a designer and manufacturer are not in the same place or country to work, when they use significantly different languages, or when something is difficult to be explained to each other. However, these technical drawings and symbols are not so easy to draw using computers. In this research, an apparel technical drawing application program, the database system, and its construction method were developed.
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Since 1997, the Korea Institute of Industrial Technology (KITECH) have studied a computer integrated manufacturing and database management system for the construction of quick response system using computer network in the apparel industry. This system interconnected in the process with integrating peripheral systems. This system is a kind of graphic program, used to construct a technical drawing by using computer with database. System construction The system consists of an application program and a modulized database system. The application program has been developed for the apparel technical drawing with useful and essential functions, extracted and added from existing graphic tools. Some functions have been modified to reflect the taste of the endusers, and the fundamental format of the program has been made by Scalable Vector Graphics (SVG) format. This SVG format is a next generation extensible graphic format that can express a 2-dimensional device, bitmap object, or text by XML (eXtensible Mark up Language) computer language. Using this method, most of the 2-dimensional devices, styles, interactives, transforms, animations can be expressed impeccably. In this system, we have constructed the internal data structure which can convert the data in the easiest possible manner into the SVG format. And also using the import/export functions, a lot of existing solutions can be supported to convert their data into the system (Figure 1). Distinguished functions To represent a synergetic object drawing effect, a mixed technology was used with bitmap and vector drawing function. This technique has been tried to solve the limited conversion problems, which happened frequently in the field, and to express an object with multiple and various graphic effects. In other words, it can realize to fill a vector object with bitmap object. The second feature of this application program is a stroked fill mode. The existing drawing tools allow one line style towards a segment (for constructing
Figure 1.
one object) but, in the garment technical drawing or in the garment construction details, a multiple type of line stroking is sometimes necessary (Figure 2). Commonly, when we construct a computer communication system that enables us to connect each production process, we are faced with the difference of colors of object on the screen and on the hard copied print out. At this stage of development, we tried to apply the color matching technology to solve the problem. Moreover, to imagine a real sized garment, the accurate geometry function, which enables us to show an object with the real size simulated ruler on the screen, has been developed. And to express realistically, the alpha composition function has been applied to a transparent fabric such as see-through fabrics. The compound path function for a holed design and free texture mapping function are applied as an advanced feature.
Garment technical drawing system 249
Database system The advantage of this system is that it enables us to construct a database system for a garment’s partial element drawing, the construction details, and the stitch symbols. Generally, it is not so easy for an end-user to draw a technical drawing using computer. To support this problem, we have developed a template-based database system constructed by types, items, styles, and parts of garment. These drawing database are stored in the classified library and used by just clicking buttons. Each garment element can be coordinated using specified combination methodology when used, like the principle of a puzzle game. This methodology is more easier and more rapid if it is compared with the way of drawing in manuscript on the white board (Figure 3). Expectancy effect and further research This apparel technical drawing system and its template-based database system can improve product quality, and reduce the cost and defects during
Figure 2.
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Figure 3.
the manufacturing process. Thanks to the precision transmission of the designer’s concept to the manufacturer, we can expect varied effectiveness in the industry such as short delivery and cost reduction, easy communication using multinational communication means—drawing, data storage, and data management task. According to the recent market requirements for various types of products and designs, apparel mills must make up a garment with more shortened delivery than in the past. This tendency implies that it needs more powerful and more useful computer system in the process. To get a more advanced and more useful system, room for improvement should remain for further researches such as the more expanded graphic data conversion technology, or the more advanced user-defined interface development. Consequently, it is prerequisite to provide and improve computerization of the workflow process, the development of more powerful interactive data conversion technology. Further reading Cho, K.I. (1997), Database Design, Hongrung Science Publishing. Harold, E.R. (2000), XML Bible, Information Publishing Group. JI, Y.A. (1995), “Computerization of technical file” final project report, ESIV & Decathlon Production International, FR. http://www.corel.com http://www.craneis.co.uk/corel/intro.html http://www.w3org/XML
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Effect of thermal radiation from fabrics on human body Toshinari Nakajima Showa Women’s University, Setagaya-ku, Tokyo, Japan
Effect of thermal radiation from fabrics 251
Yuki Hachino and Haruko Yamano Ochanomizu University, Bunkyo-ku, Tokyo, Japan Keywords Clothing, Temperature Abstract The effectiveness of the far infrared radiation processing cloth as clothing material is discussed. Temperature rise of the irradiation plane is more rapid than the heating by heat conduction and convection for the radiant heating. Skin temperature change and thermal sensation of the examinee wearing the sweater with a plastic heater at back were examined. “The relation of the inverse proportion of heat intensity to the time needed until the extent of thermal stimulation perceived was examined. Individual examinees tested, by oral contact, the extent of the pleasant sensation produced by the warming condition. They judged the extent of the warming according to whether it felt comfortable. Individually, they differed a great extent in their opinion of what was comfortable. However, for all examinees, the relationship of warming and feeling comfortable was confined within narrow parameters. In this experiment, a unit of the radiant heat stimulation was determined by dividing mW/cm2 by the warming period, since intermittent warming was carried out.” The degree of the skin temperature perceived by the sensation was almost fixed at 33 – 35, even if the radiant heat strength differed. The rapid thermal stimulation by radiant heating can be perceived even for a slight temperature rise of the skin. It is also necessary to consider the temperature rise speed, except for the temperature rise of the cloth surface, when the effectiveness of the far infrared radiation processing cloth was discussed.
Introduction A new textile finish will come in the near future, which has an energy transfer mechanism, for example, from short-wave radiation to long-wave radiation (heat regeneration), and also from long-wave radiation to short-wave radiation. The mechanism of photochemical reaction with reversible prototropy can be applied and some kinds of dyestuff derivatives can also be applied. We intend to develop a measurement device for the evaluation of these kinds of fabrics. Recently, many kinds of far infrared regenerating fabrics have arrived in the market in Japan. Purpose of the research is to have some basic concepts to develop a new type of evaluation method for far infrared regenerating fabrics, and to have some knowledge of the effect of thermal radiation from fabrics on human body. Temperature rise of the irradiation plane is more rapid than the heating by heat conduction and convection for the radiant heating. Method The experiment was carried out in a climatic chamber. The environmental condition was 23, 50 per cent RH. It was the temperature which was a little
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lower than that which the subjects felt comfortable when sitting quietly. Seven healthy female college students and six healthy male students were treated as subjects. Physical characteristics of the subjects are shown in Table I. Skin temperature change and thermal sensation of subjects in wearing the sweater with a plastic heater at back were examined. Figure 1 gives an outline of the subject under experiments. The heater was fixed to a part of the back of the sweater for the experiment. The subject sat in the chair without backrest during the experiment. The back skin temperature and the rectal temperature of the subject were measured by the thermocouple, and the skin side temperature of the heater was also measured. Simultaneously, seven local skin temperatures were measured every 4 s, and the mean skin temperature was calculated by the Hardy and Du-Bois method. The back skin blood flow was measured by the laser Doppler blood flow meter every 4 s. On/off of the electricity of the electric heat circuit was programmed between 0.1 and 1.0 s. The thermal stimulation was controlled in on/off of the electricity of the electric
Subject
Table I. Physical characteristics of the subjects
Figure 1. An outline of the subject under experiments
HM KH KN KS MH YS AT HY NY OM OS TT YK
Sex
Age
Height (m)
Weight (kg)
Body surface area (m2)
Male Male Male Male Male Male Female Female Female Female Female Female Female
23 23 23 23 22 23 22 23 23 21 23 21 21
1.69 1.64 1.63 1.69 1.83 1.75 1.54 1.60 1.63 1.58 1.54 1.56 1.49
65.0 53.1 63.5 65.0 52.7 63.1 48.0 47.7 49.0 53.3 37.0 43.4 42.1
1.76 1.58 1.70 1.76 1.71 1.78 1.45 1.49 1.52 1.54 1.30 1.40 1.37
heat circuit. The radiant heat was set at 20, 140, 220, 320, and 430 mW/cm2 at Effect of thermal the five stages. The blind test for electric power supply to a part of the radiation from examinee in the heater was carried out. The examinee reported the time fabrics perceived for the hyperthermia stimulation, and the time needed to report was recorded. Comfort sensation, and thermal sensation at the back of the examinee were reported. 253 Results Figure 2 shows the plots of the thermal stimulation against sensation. The plots look like a hyperbolic curve. Figure 3 shows the linear relationship between skin temperature change perceived and the radiant heat flux in both
Figure 2. The thermal stimulation against sensations
Figure 3. Skin temperature change perceived and the radiant heat flux
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Figure 4. Relationship between the radiant heat flux and the back skin temperature perceived the sensation
Figure 5. The beginning to stuffy feeling by approximating mean skin temperature (Ushioda et al., 1995)
logarithmic plotting. Figure 4 shows the relationship between the radiant heat flux and the back skin temperature perceived the sensation. The degree of the skin temperature perceived by the sensation was almost fixed at 33 –35, even if the radiant heat flux was different. This temperature corresponds to the supreme vicinity of the neutral skin temperature. We have already reported that it begins to feel uncomfortably by approximating the mean skin temperature 34.2 (see Figure 5; Ushioda et al., 1995). It was possible that the hyperthermia stimulation was perceived even for a slight temperature change, when the radiant heat strength was high. No performance was seen in perceiving the hyperthermia stimulation, if the rise degree of skin temperature is not high, when the radiant heat strength is low. It was also found that when the rise in skin temperature was high, the radiant heat strength was low. This result agrees with Hensel’s (1981) report. The threshold of the sensation increased with the lowering of the temperature change rate. A linear relationship was obtained when both the logarithm coordinates were plotted in
the required time, until the radiant heat strength was perceived with the Effect of thermal stimulation. radiation from Discussion The initial skin temperature at back is defined as Ti. The skin temperature at the time when the subject perceived the temperature change is defined as Tt. Tt2Ti is the skin temperature rise. The skin temperature rise was plotted in both logarithms against the radiant heat flux. There was an individual difference among subjects. However, there was an inversely linear relationship on the skin temperature rise for the thermal stimulation quantity of the identical subjects. At a particular instant when the subject perceived temperature change, the skin temperature kept rising higher. Highest skin temperature in programmed heating time is defined as Tf. Thus, Tf2Ti was defined as the highest skin temperature rise. The highest skin temperature rise was plotted against radiant heat flux. There were some subjects who were sensitive to heat, and another group of subjects, who were insensitive to heat. The subjects had the individual difference. Stevens law was found valid for the relation between the highest skin temperature rise and the thermal stimulation quantity of identical subjects. Figure 6 shows the back skin temperature rise against the radiation heat flux. The vertical axis is the temperature difference between the final temperature and the initial temperature at back. The variation of plots between subjects showed differences among individuals. This result agrees with Stevens power function law. It is proven that rapid stimulation load kicked for radiant heating can be perceived even for a slight temperature rise of the skin. Figure 7 shows the relationship between the skin temperature change perceived and the radiant heat flux in both logarithm plotting. The vertical axis in the figure is the temperature difference between the initial temperature and the temperature when the subjects perceived the hyperthermia stimulation at
fabrics 255
Figure 6. The back skin temperature rise against the radiant heat flux
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back. These plots also show individual variation. These results show that the rapid thermal stimulation by radiation heating can be perceived even for a slight temperature rise of the skin. These results agreed with the physiological studies of thermoreception (Hensel, 1981). Conclusion The rapid thermal stimulation by radiant heating can be perceived even for a slight temperature rise of the skin. It is necessary to consider the temperature rise speed also, except for the temperature rise of the cloth surface, when the effectiveness of the far infrared radiation processing cloth is discussed. References Hensel, H. (1981), Thermo Reception and Temperature Regulation, Academic Press, New York 20 pp. Ushioda, H., Aoki, A. and Nakajima, T. (1995), “A factor on humid sense”, J. Jpn. Res. Assn. Text. End-Uses, Vol. 36 No. 1, pp. 162-4.
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Structural mechanics of knitted fabrics for apparel and composite materials
Structural mechanics of knitted fabrics 257
Ron Postle University of New South Wales, Sydney, Australia Keywords Knitwear, Physical properties Abstract The importance of fabric biaxial extension, in-plane compression, shear and bending properties, have been widely recognised by textile scientists and engineers for the evaluation of the three-dimensional formability and drape of textile materials in apparel products and threedimensional preforms. In contrast to woven fabrics where bending and shear properties determine the fabric formability, knitted fabrics have very high formability as a direct result of their easy biaxial extension properties. This ability to form three-dimensional shapes using the biaxial extensibility of knitted structures enables these knitted textile materials to be utilised for a wide variety of close fitting apparel garments and shaped composite preforms. Some representative biaxial extension curves for the plain knitted structure are described in this paper. These curves illustrate an unusual shape for the load-extension curve of a textile material arising from the pretension or pre-stress. The pre-stress yields an initial high tensile modulus for the structure in contrast to the very low initial modulus characteristic of apparel textiles. Accordingly, for knitted textile materials, it is shown how biaxial extension of the fabric introduces a fabric pre-stress to maximise the three-dimensional fabric formability especially when subjected to transverse compression by the resin or matrix in a composite material. Typical uniaxial and biaxial tensile stress – strain curves for knitted fabrics are compared.
1. Introduction Concentrating on the plain weft-knitted structure, we investigate uniaxial and biaxial extension in this section and transverse compression in a subsequent section. The mechanisms of deformation are studied for each of these mechanical properties. The load-extension properties of knitted fabrics have been investigated theoretically by several workers (Shanahan and Postle, 1974a; Popper, 1966; Whitney and Epting, 1966; Kawabata et al., 1973; MacRory et al., 1975; Shanahan and Postle, 1974b), acknowledging the importance of this subject as far as the end use of knitted fabrics is concerned. Popper (1966) and Whitney and Epting (1966) analysed the biaxial deformation of plain-knitted fabrics after a sufficient load had already been applied to straighten the threads in the fabrics. Kawabata et al. (1973) used as their model a fabric built up from several bent and loaded yarn segments and assumed that a yarn segment extends so that the slope of the yarn remains constant at the extremity of the segment. Further geometrical assumptions were made in applying this technique to an
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actual fabric. MacRory et al. (1975) used a similar technique but, instead of the two-dimensional model of Kawabata et al. (1973), they used a three-dimensional model and assumed that the shape of the yarn in the contacting region of the plain-knitted fabric could be described by a helix. This technique ignores the deformation of certain segments within the structure. Theoretical load-extension curves for plain-knitted fabric have been derived by three force methods (MacRory et al., 1975; Shanahan and Postle, 1974b; Hepworth, 1978, 1980). Except for the analysis of walewise extension by Shanahan and Postle (1974a, b), all the predicted tensile moduli were higher than the experimentally observed values. Only two methods of analysis have been capable of including both length and width jamming in the determination of the tensile properties of plainknitted fabric. Using the Hepworth and Leaf force model, Hepworth (1980) predicted the load-extension behaviour of plain-knitted fabrics under uniaxial and biaxial tension. de Jong and Postle (1977) determined the effects of very small uniaxial loads ðPL 2 =B ¼ 2Þ [1] on the plain-knitted loop, using the energy model. The energy analysis includes yarn compression, which is omitted from the Hepworth and Leaf force model. The energy analysis is used here to predict fabric tensile behaviour at uniaxial and biaxial (dimensionless) loads up to PL 2 =B ¼ 4:0: A wide range of biaxial load ratios is used.
2. Uniaxial extension Uniaxial load-extension curves Load-extension curves calculated from the energy considerations for plainknitted fabrics are shown in Figure 1 for uniaxial walewise loading and in Figure 2 for uniaxial coursewise loading. The figures also provide a comparison with the results of the force analysis of Hepworth (1980). The sharp changes in the modulus, characteristic of the Hepworth and Leaf force model, are absent from the results of the energy equations because the onset and release of jamming are gradual processes when yarn compressibility is included. Jamming forces cause a pre-stress when they are parallel to the direction of extension (Hepworth, 1980) and a restriction on fabric extensibility when they are normal to the direction of fabric extension. Although the fabric as a whole is not loaded at zero tension, there is a pressure exerted between yarns where jamming occurs in the relaxed structure. This pressure is counterbalanced by a yarn tension existing elsewhere in the loop. This pre-stressed jammed structure was quoted by Hepworth (1980) as the reason for the discontinuity in the uniaxial tensile load-extension curves predicted from the model incorporating incompressible yarns. Typical computed shapes of the plain-knitted fabric in its relaxed, walewise extended state and coursewise extended state are shown in Figure 3.
Structural mechanics of knitted fabrics 259
Figure 1. Uniaxial load-extension curves for the plainknitted structure in walewise loading, showing the effects of yarn compression index a and fabric tightness dmin/L, for (a) walewise extension and (b) coursewise extension (in walewise loading): curve 1, a ¼ 10; d min =L ¼ 0:22; curve 2, a ¼ 20; d min =L ¼ 0:22; curve 3, a ¼ 20; d min =L ¼ 0:26; curve 4, results of Hepworth, d=L ¼ 0:22; curve 5, results of Hepworth, d=L ¼ 0:26:
Frictional resistance to slippage The significance of the inter-yarn forces calculated by the energy method in relation to frictional slippage in the fabric is of interest. Yarn tension in the interlocking regions is approximately equal to the fabric tension per loop and the direction of the inter-yarn forces at the point of closest contact is almost normal to the yarn axis. Therefore, slippage of the yarns past each other occurs in the contact region when fabric tension per loop .m total inter-yarn force
ð1Þ
where m is the coefficient of friction between the yarns. Thus, once m is known, equation (1) can be used to determine whether interyarn slippage occurs. The range of m for yarn-to-yarn friction is approximately
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Figure 2. As Figure 1, but coursewise loading: (a) coursewise extension and (b) walewise extension (in coursewise loading)
0:1 , m , 0:4 (Yanagawa et al., 1970). If the ratio on the left-hand side of equation (1) is high relative to m, the interlacing yarns are likely to slip during fabric extension. In this way, it has been calculated (Hart, 1981) that the interlacing yarns are more likely to slip when the plain-knitted fabric is extended in the wale direction. Setting increases the ratio on the left-hand side, thereby facilitating yarn slippage during fabric extension. The jamming forces As the fabric is extended uniaxially, the jamming forces between neighbouring loops increase in the direction normal to extension. In walewise extension the width jamming yarns come closer together (see Figure 3(b)), thereby increasing the force between the interlacing yarns (Hart, 1981). This would reduce the
Structural mechanics of knitted fabrics 261
Figure 3. The effect of yarn slippage on jamming for the plain-knitted structure: (a) untensioned fabric (W and L indicate where width and length jamming will occur); (b) walewise tension (the direction of slippage, labelled DS, puts more yarn in the stem of the loop, bringing the widthjamming yarns closer together); (c) coursewise tension (the direction of slippage puts more yarn in the arc, bringing the length-jamming yarns closer together)
tendency for the interlacing yarns to slip. Similarly, in coursewise extension, Figure 3(c) shows that the length-jamming yarns come closer together again, increasing the force between interlacing yarns. This would also reduce the tendency for further yarn slippage to occur. In contrast, jamming in the direction of extension decreases very rapidly with increasing applied tensile load, and the magnitude of the jamming force is comparable with the difference observed between the initial modulus and the modulus after the jamming has diminished. Thus the jamming pre-stress effect explains the initially high tensile modulus of the theoretical curves.
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Yarn compression The principal effect of yarn compression is to increase fabric extensibility. The area of contact is larger between interlocking yarns for compressible yarns than for relatively incompressible yarns, resulting in decreasing freedom of movement in the fabric. For compressible yarns, these effects give the high pre-stresses at very low loads and the high fabric rigidity up to loads of PL 2 =B ¼ 4; which are shown most clearly in Figure 1(a). As the tensile load increases further, fabric extension by the mechanism of yarn compression becomes significant, not only because of compression in the interlocking region, but also because of compression between jamming yarns at right-angles. In walewise extension, for example, yarn compression between width-jamming yarns allows more reduction in the length of the arc of the loop by yarn slippage, as shown in Figure 3(b). 3. Biaxial extension The tensile properties of plain-knitted fabrics have been calculated (Hart, 1981) from the energy equations under many combinations of walewise and coursewise biaxial loads. The biaxial condition, P c L 2 =B ¼ 2P w L 2 =B; was used for the biaxial load-extension curves shown in Figure 4, where Pc and Pw are the loads applied in the course and wale directions, respectively. In Figure 5 a family of biaxial load-extension curves has been developed using a fixed walewise load PwL 2/B and varying the coursewise load PcL 2/B. The stress values were based on relaxed fabric dimensions. Computed shapes are shown in Figure 6 for the plain-knitted structure in the relaxed state and the biaxially extended state for equal biaxial stress, PL 2 =B ¼ 20: At high fabric tensions and when the coursewise load is greater or equal to the walewise load ðP c L 2 =B $ P w L 2 =BÞ; the fabric is usually in compression in the walewise direction (negative walewise extension in Figures 4 and 5) and the length-jamming forces are large, as in uniaxial coursewise extension. Comparison with the analysis of Hepworth (1980) in Figure 4 shows good agreement, particularly at high loads. The main difference is that, in Hepworth’s results, fabric extensibility varies less with fabric tightness. This effect is related to yarn compressibility. For compressible yarns used in the energy model, the area of contact increases with increasing fabric tightness; this causes a reduction in the freedom of movement in the fabric. Even without yarn compression, freedom of movement is reduced by increasing tightness but yarn compressibility magnifies the effect. The jamming forces fall very rapidly in biaxial extension. If it were not for the increase in yarn compression during biaxial extension, the initial reduction in bending energy for slack fabrics would cause a negative modulus in part of the load-extension curve, as illustrated in the results of Hepworth in Figure 4. In contrast, the compression energy decreases with increasing load initially for tight fabrics, while the bending energy increases. The jamming forces are so
Structural mechanics of knitted fabrics 263
Figure 4. Biaxial tensile loadextension curves for the plain-knitted structure, where P c L 2 =B ¼ 2 2P w L =B; showing the effect of fabric tightness dmin/L, for (a) the coursewise direction and (b) the walewise direction: curves as in Figure 1
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Figure 5. Biaxial tensile loadextension curves for fixed walewise loads PwL 2/B (values indicated on the curves) and varying coursewise loads PcL 2/B for (a) coursewise extension and (b) walewise extension (fabric compression index a ¼ 10; fabric tightness d min =L ¼ 0:22; highly set fabrics f ¼ 0:99); †, experimental results of MacRory et al..; - - - - -, load combinations that cause no inter-yarn slippage
large that their reduction is responsible for most of the changes in compression energy. A large variation in the ratio of the walewise load to the coursewise load is shown in Figure 5. Coursewise extensibility is generally greater than walewise extensibility because of the ease of yarn straightening in the arc of the loop. Walewise contraction is larger than coursewise contraction, but it only occurs when the coursewise load per yarn is greater than the walewise load per yarn. Slippage is the main cause of contraction but Figure 5 shows that a small walewise contraction still occurs for the particular load ratio where there is no slippage. Figure 5 is most useful for experimental comparison because experimental testers cannot easily apply a constant load ratio. The results of MacRory et al. (1977) agree very closely with the predicted deformations in both fabric directions. The dmin used in Figure 5 is less than the yarn diameter measured by MacRory et al.. Experimental methods of determining yarn diameter appear to overestimate dmin because of yarn flattening in the contacting region. It is this effect far more that the yarn compression during fabric extension that explains the large discrepancy between the model of MacRory et al. and their experimental results. Results computed from the energy equations show that an extreme range of compression indices does not cause more than 30 percent variation in fabric extensibility (Figure 6).
Structural mechanics of knitted fabrics 265
4. Transverse compression of the plain-knitted structure The transverse compression force was applied at the end point of the loop (Hart, 1981). An alternative method would be to simulate compression between parallel plates. This latter method would allow more accurate specification of fabric thickness, but would differ only slightly from the present analysis at the low pressures used. At high pressures such as those which exist in a composite material, the usefulness of theoretical results is limited by the accuracy of the compression energy function. A maximum compressive load of PL 2 =B ¼ 5 was used to derive, from energy considerations, the series of transverse load-compression curves shown
Figure 6. Fabric plane projections of the plain-knitted structure for (a) relaxed fabric and (b) fabric under equal biaxial stressed ðPL 2 =B ¼ 20; a ¼ 20; d min =L ¼ 0:22Þ:
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Figure 7. Transverse load – compression curves for the plain-knitted structure calculated from the energy equations, showing the effects of the yarn compression index a and the fabric tightness dmin/L for set fabrics with form factor f ¼ 0:99 : curve 1, a ¼ 10; d min =L ¼ 0:22; curve 2, a ¼ 20; d min =L ¼ 0:22; curve 3, a ¼ 20; d min =L ¼ 0:235; curve 4, from the formula derived by Williams and Leaf, i.e. t ¼ a þ b exp½2kðPL 2 =BÞ; where a ¼ 0:417; b ¼ 0:089 and k ¼ 0:256
in Figure 7. For a typical plain-knitted fabric used by Postle (1971), this load is equivalent to a pressure of 84 kPa, slightly larger than the maximum pressure used experimentally. Figure 8 shows that the transverse compression modulus for the plainknitted structure decreases and therefore the fabric compressibility increases with increasing fabric slackness and yarn compressibility. The main mechanisms are the rotation of the arc of the loop into the fabric plane and yarn compression. The former causes an increase in the course spacing and a build-up of the length-jamming forces. This rotation also reduces the fabric width. This effect is most easily understood by considering the arcs of the loop as rotating links of a chain. A counteracting effect is caused by the increase in width-jamming forces. The jamming forces are so large for very tight fabrics that the fabric extends coursewise during transverse compression. Figure 8 shows that the following equation for the fabric thickness t of the form derived by Williams and Leaf (1974) from experimental results fits the theoretical curve within 5 percent: PL2 t ¼ a þ b exp 2k ð2Þ B where a ¼ 0:417; b ¼ 0:089 and k ¼ 0:256: The constants used in this equation have been chosen to give the correct moduli at 0 and PL 2 =B ¼ 5: All three constants are dependent on fabric parameters, as concluded by Williams and Leaf (1974). The measurement of fabric thickness t/L at almost constant dmin, as performed experimentally, is equivalent to finding t/dmin at a constant
quarter-loop length L. There is only a small variation (less than 3 percent) in t/dmin with changing fabric tightness dmin/L (Hart, 1981). This small variation may not be detectable experimentally. The thickness increases with the fabric tightness for the plain-knitted structure, but not linearly.
Structural mechanics of knitted fabrics
5. Conclusion Several modes of tensile deformation of the plain-knitted structure have been studied. Using the forces, couples, energies and loop shapes that can be evaluated from energy considerations, the mechanisms of knitted fabric extension have been analysed. Previous studies have concentrated on isolated elements of the deformation, but in this paper, the interplay of the major mechanisms – yarn bending, slippage, yarn compression and jamming – has been described in order to explain the overall fabric tensile behaviour. A redistribution of yarn curvature has the largest single influence on fabric extension and results in greater extensibility in the coursewise direction than in the walewise direction. Structural jamming gives an initial pre-stress in the direction of extension and, at high loads, jamming normal to the direction of extension increases the fabric modulus. Jamming is less significant in biaxial extension than in uniaxial extension for plain-knitted fabrics. Slippage is large in uniaxial extension but would be greatly reduced by friction if it were included in the theoretical analysis. Fabric setting would reduce the frictional resistance. Yarn compression can increase knitted fabric extensibility by up to 30 percent in the load range used (maximum PL 2 =B ¼ 40). Yarn compressibility reduces the amount of curvature in regions of loop interlocking and weakens the effect of jamming at high loads.
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Figure 8. Initial modulus of fabric transverse compression for the plain-knitted structure plotted as a function of fabric tightness dmin/L for different values of the yarn compression index a and of the degree f of set: curve 1, f ¼ 0:99; a ¼ 30; curve 2, f ¼ 0:99; a ¼ 20; curve 3, f ¼ 0:99; a ¼ 10; curve 4, f ¼ 0:99; a ¼ 5; curve 5, f ¼ 0; a ¼ 20; curve 6, f ¼ 0; a ¼ 10:
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The relaxed or unstressed shape of the knitted structure encountered in knitted apparel yields the characteristic very low initial tensile modulus. On the other hand, the shape of the biaxially stressed or pre-tensioned knitted structure yields the high initial tensile modulus evident from the almost linear yarn segments comprising the pre-stressed knitted loop shape. This latter prestressed structure enables the superior formability of knitted textile materials to be adapted to the production of the three-dimensional composite material preforms. It is clear that we need to interact strongly with the mathematical disciplines of differential geometry and nonlinear dynamical systems in order to advance this challenging field of study. The rewards are potentially very great because success would yield dynamic analytic mathematical solutions to very practical problems in textile, clothing and composite materials science and technology. Such solutions would, for example, facilitate the dynamic display in real time of three-dimensionally deformed textiles or fashion garments on a computer screen since no time consuming numerical procedures for solving complex fabric deformation problems would be required. Note 1. P is the externally applied force; L is the knitted quarter-loop length; and B is the yarn bending rigidity. References de Jong, S. and Postle, R. (1977), J. Text. Inst., Vol. 68 No. 10, pp. 324-9. Hart, K.R. (1981), The mechanics of plain weft and single-bar warp-knitted fabrics using energy minimization techniques, Ph.D. Thesis, University of New South Wales. Hepworth, B. (1978), J. Text. Inst., Vol. 69, pp. 101-7. Hepworth, R.B. (1980), Some aspects of the mechanics of a model of plain weft-knitting, in J.W.S. Hearle, J.J. Thwaites and J. Amirbayat (Eds.), Mechanics of Flexible Fibre Assemblies, Sijthoff and Noordhoff, Alphen aan den Rijn, pp. 175–196. Kawabata, S., Niwa, M. and Kawai, H. (1973), J. Text. Inst., Vol. 64, pp. 21-85. MacRory, B.M., McCraith, J.R. and McNamara, A.B. (1975), Text. Res. J., Vol. 45, pp. 746-60. MacRory, B.M., McCraith, J.R. and McNamara, A.B. (1977), Text. Res. J., Vol. 47, pp. 233-9. Popper, P. (1966), Text. Res. J., Vol. 36, pp. 148-57. Postle, R. (1971), J. Text. Inst.,, Vol. 62, pp. 586-8. Shanahan, W.J. and Postle, R. (1974a), J. Text. Inst., Vol. 65, pp. 200-12. Shanahan, W.J. and Postle, R. (1974b), J. Text. Inst., Vol. 65, pp. 254-60. Whitney, J.H. and Epting, J.L. Jr. (1966), Text. Res. J., Vol. 36, pp. 143-7. Williams, R.C.G. and Leaf, G.A.V. (1974), J. Text. Inst., Vol. 65, pp. 380-3. Yanagawa, Y., Kawabata, S., Toyama, K. and Kawai, H. (1970), J. Text. Mach. Soc. Jpn, Vol. 16, pp. 216-28.
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A preliminary study for evaluation of skirt asymmetric drape V. Sidabraite and V. Masteikaite
Accepted March 2002
Kaunas University of Technology, Kaunas, Lithuania Keywords Garments, Fabric, Drape, Evaluation Abstract Undesirable effect of asymmetric drape often occurs when cutting patterns of flared skirt on cross. Out of this reason garment seams twist toward the front or back or folds form different shapes on each side of the garment and this lowers garment aesthetic appearance. The new measuring procedure for asymmetric skirt drape near the side seam, based on bottom traces geometry, was developed in this paper. The experiment with four-gored skirts of six lightweight fabrics was made. It was found that asymmetric drape depends on combination of grain lines directions of front and back panels of a skirt. There were made general conclusions relating skirt asymmetric drape with various fabric characteristics, such as bending rigidity, extensibility, shear rigidity, fabric weight and drape coefficient in this article. According to developed measuring procedure a final objective evaluation of skirt asymmetric drape rate will be done further.
International Journal of Clothing Science and Technology, Vol. 14 No. 5, 2002, pp. 286-298. q MCB UP Limited, 0955-6222 DOI 10.1108/09556220210446103
Introduction The new generation of 3D computer-aided design systems for fashion design and garment industries is coming. It may be possible in the near future for virtual fashion show and home shopping to become a reality. It requires precise fabric, garment and synthetic human models to predict the true 3D behavior of garments from various textile materials. It is generally accepted that one of the most important requirements for the development of a 3D garment CAD system is how to obtain the real shape of the garment in 3D space from the original 2D design patterns. It was realized that the deformable behavior of textile materials, such as fabric drape, would play a very important role in this area. The ability of fabrics to drape into complex 3D shapes provides a graceful aesthetic effect for apparel and other industrial design and uses. This aesthetic effect depends on fabric structural and mechanical properties. The wide variety of modern fabrics provides us to get a lot of different drape and fold shapes. For this reason the measurement of drape is required to specify the performance of fabric. Chu et al. (1950) started first a 3D study of drape. Instruments for measuring drape ability have been developed by Chu et al. (1950) and later by Cusick (1965, 1968).
The earliest studies of fabric drape have been mainly directed to fabrics Evaluation of without seams. Nevertheless, the formation of a seam in a fabric influences its skirt asymmetric drape. Hu et al. (1997, 1998) investigated the effect of seams on fabric drape. drape The relationships between fabric drape ability and seam allowance, seam positions and seam directions have been studied in terms of drape coefficient and drape profile, evaluated by The Cusick’s Drape meter, and bending length, 287 measured by the FAST-2 bending tester and Peirce’s Flex meter in a paper of Hu et al. (1997). They concluded that the drape behavior of a fabric with seams seem to be much more complicated than that of fabrics without seams. Seam positions, seam types, seam structure, seam directions and testing methods all affect the results. Later Hu et al. (1998) studied both radial and circular seams sewn onto fabric specimens. They have found that drape coefficient increases with the addition of a radial seam. The drape profile of an unseamed fabric is not stable, but the drape profiles of fabrics with two and four radial seams are more stable and regular. On the other hand, the number of seams shows a great effect on both drape coefficient and drape profile for heavyweight fabrics, but very little effect on lightweight fabrics. Nevertheless, node length can detect the effect of radial seams on lightweight fabrics. For a fabric with a circular seam, they have found the highest drape coefficient when such seam is located just off the pedestal edge. Any outward movement of the seam causes drape coefficient to fall. The paper about bending behavior of woven fabrics with vertical seams furthers the investigation of Hu et al. (2000). They related the experimental results of bending length to the second moment of area of the fabric cross section, involving the study of seam structures, such as fabric thickness, seam thickness, seam allowance, distance of neutral axis from the surface of the fabric cross section, and width of the fabric strip. Investigation of fabric drape with seams has a significant value for both the textile and clothing industries because it provides a realistic drape study with respect to garment appearance. On the other hand, to evaluate seam effect only on fabric drape is not enough. The finished garment’s drape depends on its geometry too (Armstrong, 1995). The most part of fabric drape experiments was made with circular specimens (Cusick, 1965; Hu, 1997, 1998). Some drape experiments are made with quadratic specimens (Ascough et al., 1996; Chen and Govindaraj, 1995, 1996; Gan and Ly, 1995; House et al., 1996). But there are very few examples about researches with realistic form of garment. However, the next generation of textile and garment manufacturing and automated retailing systems is coming. These systems will need to predict the true 3D behavior of the fabric and garment design and wear (Stylios et al., 1995). The major task for researches working on that is to find precise and efficient approach to determine the real 3D deformed shape of a cloth according to real fabric properties and to deal with complex 3D design patterns.
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Stylios et al. (1995, 1996) developed the deformable node-bar model based on physical analogue to a deep shell system that is capable to deal with the complex deformation of fabric in garment. The model has been verified with the simulation of a real drape system and with the simulation of the dynamic draping of a skirt, which is worn by a synthetic lady. A new collision technique has been presented in later reference (Stylios, 1997). The real forms of garment were used in other papers that describe numerical garment simulations (Dai et al. 2001; Hu, 2000), too. However, while the geometric methods enables to simulate cloth drape simply and quickly, the details, such as effects of cloth anisotropy and seaming lines, are difficult to reflect well and the high computational cost still remains a problem to be solved (Dai et al., 2001). The other important influence on garment drape makes the grain alignment. Orzada et al. (1997) examined the effects of a common apparel industry practice, tilting patterns off-grain on fabric and garment drape evaluations. Degree of tilt significantly increased shear stiffness and hysteresis for the twill fabrics examined in their study. In addition, off-grain fabric specimens exhibited more asymmetrical shear curves. However, since there was no consistent relationship between tilt angle and drape value, an objective measure of amount of drape, the most significant effect of tilting may be on drape symmetry and appearance. Because of a fact that there are limit researches related to investigation of realistic garment drape behavior, this study was designed to examine the drape behavior of four-gored skirt drape. The main purpose of this study is to analyze the appearance of asymmetric drape near the side seams of skirt, because undesirable garment drape occurs when garment seams twist towards the back or front or when folds form different shapes on each side of the garment. Data from an apparel industry survey were utilized to establish specimen geometry and pattern pieces positioning for drape analysis.
Methodology According to the research object, the following methodology was created and followed. Skirt pattern design methodology (Aldrich, 1997) was used to draft the patterns of skirt front and back panels (Figure 1). For better skirts hang the grain line was taken in the center of a panel and makes 458 angle with lengthwise direction. Due to chosen construction of a skirt and position of the front and back panels in the pattern there are four variants of the half skirt’s appearance taking the angle ai between the grain line of the panels and the side seam of the skirt into consideration (Figure 2). When lengthwise direction coincides with warp direction, the direction of grain line is called bias warp direction and due to skirt’s flare it makes an angle
a1 ¼ 458 þ 138 with the side seam of the back panel or a2 ¼ 458 2 138 angle Evaluation of with the side seam of the front panel. When lengthwise direction coincides with skirt asymmetric weft direction, the direction of grain line is called bias weft direction and makes drape a2 ¼ 458 2 138 angle with the side seam of the back panel or a1 ¼ 458 þ 138 angle with the side seam of the front panel. The scale of drafted skirt patterns was 1 : 2. Parts of patterns from hip line to 289 hem line (Figure 1) were used for the experiment. The upper part of patterns was ignored because the upper part of skirt hangs close to woman’s body and does not drape. In addition, after sewing front and back panels together they take the 3D shape, and it is more complicate to investigate 3D specimen. In this research, we examined a half of skirt consisting of front and back panels. The behavior of other part of four-gored skirt is similar. Specimens for the experiment were cut from six lightweight fabrics with various fiber contents and weaves. All these fabrics are suitable to produce four-gored skirts. The details are shown in Table I.
Figure 1. Patterns of four gored skirt (a) back and (b) front details
Figure 2. Variants of skirt’s front and back panels combinations according to the angle ai between the grain line of skirt’s panel and the side seam
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Table I. Fabric details
A B C D E F
Fiber composition
Weave
Polyester 35%, viscose 65% Polyester (warp), viscose (weft) Polyester 44%, silk 56% Viscose 100% Viscose 100% Cotton 100%
Plane Hopsack Hopsack Plane Plane Plane
Warp Weft Weight, (g/m2) 48 41 46 39 47 39
27 24 37 27 20 31
133 116 70 119 112 83
Thickness* (mm) 0.33 0.51 0.37 0.31 0.31 0.26
Note: * Thickness at pressure of 2 g/cm2.
The front and back panels were sewn together by sewing machine PFAFF hobby 422. The stitch density was four stitches per centimeter, the needle size was number 70, and the thread was a black polyester spun 50S/2 5000Y. Machine loading and thread tension were always kept constant. The seam allowance was pressed open and equal to 3 mm. Sewn specimens were supported at hip line at five points lying in one straight line to plate lying in horizontal position (Figure 3(a)). After supporting specimen the plate was raised into vertical position making the specimen to drape (Figure 3(b)). The front and bottom images (Figure 3) of draped specimen were captured with digital photo camera TOSHIBA PDRM70. When we were getting the front images photo camera was fixed at position 1 with the distance of about 60 cm from the plane of a specimen. When we were getting the bottom images camera was fixed at position 2 with the distance of about 80 cm from the hemline of a specimen.
Figure 3. Schematic view of a specimen supporting and images getting
The appearances of skirt front and bottom images, shown in Figure 4, differ in Evaluation of combinations of grain line direction of front and back panels, as it was skirt asymmetric explained in Figure 1. drape The front images (Figures 4(a), (b), (e) and (f)) are useful evaluating skirt drape subjectively. It is difficult to measure objectively what degree of asymmetric drape appears near the side seam of the skirt because side seam 291 hides among the folds and we can not see it (Figures 3(a) and (b)). The front images shows only the general character of the seam – is it vertical or twist towards the front or back. For objective drape evaluation we prefer the bottom images (Figures 4(c), (d), (g) and (h)). The bottom images of specimens were processed by graphical program AutoCAD 2000. Processed bottom traces of specimens were analyzed in a present study. Each trace of specimen can be characterized by number of folds, by fold geometry (length and high) and by position of a seam. Borrowing terminology from wave theory, “node length” is defined as a distance between two adjacent troughs measured along the supporting plane (measurements X1 and X2), while “node high” is defined as the distance
Figure 4. Halves of skirts with panels of different grain line position: a, b, e and f – front images, c, d, g and h – bottom images
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between a peak and adjacent trough measured along the direction perpendicular to the plane of the seam (measurements Y1 and Y2) (Figure 5). Node 1 is visually assessed as being more severe than node 2 (Figure 5) and the node severity can be defined as ratio Y/X, were Y and X are respectively a high and a length of a node. Two specimens of each grain line position variation were tested with three measurements taken of each. To evaluate fabric drape ability we used Drape meter. A circular fabric specimen was held concentrically between smaller horizontal discs, and annular ring of fabric was allowed to drape into folds around the lower supporting disc. According to Cusick (1968) the combination of a 12 cm radius fabric specimen and 9 cm radius support disc is suitable for limp fabrics, i.e. those producing a drape coefficient below 30 per cent with the template of 15 cm radius. We chose this combination because there were used lightweight fabrics in our research. The drape coefficient was calculated as the ratio of the vertical projection area to the entire sample area. The drape ability of each fabric specimen was measured three times from the face and three times from the back, making a total of six measurements on the same specimen and the mean drape coefficient of the two specimens was calculated. The results are given in Table II. However, the drape coefficient alone is not sufficient to characterize cloth drape ability. The number of folds (node number) formed by a drape sample has also been used to describe cloth drape ability. We calculated the mean node
Figure 5. A sample of bottom trace of a draped specimen
Bending rigidity (mNm) Fabric Table II. Mean values of fabric mechanical properties and drape
A B C D E F
Shear rigidity (%)
Extensibility (%)
Drape coefficient (%)
Node number
Warp
Weft
Bias warp
Bias weft
Warp
Weft
48 55 54 56 70 86
8 8 8 7 5 0
1.36 1.21 3.08 6.97 13.09 12.08
3.22 1.89 1.13 1.47 3.42 3.60
18.2 13.6 22.8 15.9 13.7 36.0
20.5 12.3 12.6 15.0 14.6 56.8
9.5 8.6 2.3 8.2 3.9 0.9
4.5 5.1 10.0 7.1 1.5 7.6
number from two specimens from a total of 12 measurements. The results are Evaluation of given in Table II. skirt asymmetric To measure fabric mechanical properties related to drape two instruments drape from the FAST fabric testing system (Masteikaite˙ et al., 2000) were utilized. The FAST-2 bending meter was used to measure the bending length and to calculate bending rigidity. The FAST-3 extension meter was used to calculate 293 extensibility and shear rigidity. The results of these measurements are taken in Table II.
Results and discussion After analysis of bottom traces of sewn specimens it was found that there are four basic shapes of traces for all fabrics (Figure 6). These shapes differ in number and geometry of nodes and side seam position with respect to Y-axis. Investigated specimens always drape into two folds of different geometry. The node on which contour is the side seam of a skirt is always higher and shorter than that without seam (Figure 6(a) and (b)). This visual assessment was expressed in terms of node severity. Severity of the node with seam is always higher then that of the node without seam. The shape of a specimen depends on the chosen combination of grain lines of front and back panels. The first and the second shapes of traces of specimens with two nodes of different high and side seam moved out of Y-axis are characteristic when both front and back panels were cut in bias warp direction (Figure 6(a)) or in bias weft direction (Figures 6(b)). The third shape of specimen’s traces with one node and side seam on Y-axis (Figure 6(c)) is characteristic when front panel was cut in bias weft direction and back panel was cut in bias warp direction. The fourth shape of specimens’ traces with two nodes of similar high and side seam on Y-axis (Figure 6(d)) is characteristic when back panel was cut in bias weft direction and front panel was cut in bias warp direction. As may be observed from Figures 6(a) and (b), the first and the second shapes of traces of specimens are examples of undesirable asymmetric drape
Figure 6. Shapes of specimens bottom traces
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while the shapes of specimens, shown in Figures 6(c) and (d), are symmetric with respect to side seam. Because the main purpose of present study is to investigate the effect of asymmetric drape on four-gored skirt the objects of our investigation are the specimens with both front and back panels cut in bias warp or bias weft direction that gives asymmetric drape. And the specimens with front and back panels cut in different bias directions serve as control. We do not use specimens without seams as control because the shapes of traces of such specimens are not always stable when tested at different times and they are not comparable with the shapes of specimens with seams. This is out of the reason that the seam has a supportive function to the drape of the local fabric and there forms a trough of a fold near the seam while we can not notice such effect on the specimens without seams. Existing asymmetric drape occurs not only for the reason of different grain line directions in front and back panels, because specimens of various fabrics with the same position of grain line behave differently. The side seams of all specimens of fabrics D and E twist toward the back, for the other fabrics the side seams of some specimen twist towards the front, some towards the back when direction of grain line is along warp. The side seam of specimens of fabrics D and F twist towards the front, the side seam of all specimens of fabrics A and E twist towards the back and for fabrics B and C some specimens twist towards the front and some towards the back when grain line’s direction is along weft. The effect of asymmetric drape may be due to the physical and mechanical characteristics of the fabrics or sewing conditions. The influence of the fabric mechanical properties and drape coefficient on the asymmetry of skirt drape can be illustrated by correlation relationships between the value of ratio X i =SX i and values of the various mechanical properties. There Xi is the length of node, SXi is the sum of lengths of all nodes of bottom trace, i is the number of nodes in bottom trace. In our case i ¼ 2; node length X 1 , X 2 ; node high Y 1 . Y 2 and node severity X 1 =Y 1 . X 2 =Y 2 : The relationship between bending rigidity in warp direction and X i =SX i in bias warp direction (Figure 7(a)) is good correlated (correlation coefficient r ¼ 0:52) for both, more and less severe nodes. Fabrics of higher bending rigidity have the lower rate of drape asymmetry near the side seam of a skirt. This is out of the fact that the length of more severe node X1 increases and the length of less severe node X2 decreases until at the value of X i =SX i ¼ 0:5 node lengths and severities become equal. Influence of bending rigidity in weft direction on the value of X i =SX i in bias warp direction (Figure 7(b)) was not observed because correlation relationship was not significant ðr ¼ 0:18Þ: The extensibility in warp and weft directions and the shear rigidity in bias warp and bias weft directions are good correlated with X i =SX i in both bias directions ðr ¼ 0:44 2 0:71Þ and the character of the relations is analogical to that one shown in Figure 7(a). The character of relation between the fabric
Evaluation of skirt asymmetric drape 295
Figure 7. The relationship between bending rigidity B and ratio X i =SX i : (a) specimens cut in bias warp direction, bending rigidity B measured in warp direction, (b) specimens cut in bias weft direction, bending rigidity B measured in weft direction
weight and X i =SX i is opposite to that shown in Figure 7. Out of this fact the difference between the lengths of nodes is higher and the drape asymmetry increases too for the fabrics of higher weight. The relation between the fabric weight and X i =SX i in bias weft direction is more significant ðr ¼ 0:85Þ than between the fabric weight and X i =SX i in bias warp direction ðr ¼ 0:35Þ: It was found that the highest correlations are between the drape coefficient and X i =SX i in bias warp direction ðr ¼ 0:76Þ and X i =SX i in bias weft direction ðr ¼ 0:85Þ: The influence of skirt construction and the sewing conditions to the asymmetry of skirt drape were not analyzed in this study and were kept constant through all the experiment. Severity of the nodes with seam and without seam of various fabrics differ in various rates. The biggest differences of severities were observed for the fabric D when panels of specimens were cut in bias warp direction (Figure 8(a))
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and for the fabric E when panels of specimens were cut in bias weft direction (Figure 8(b)). The largest difference between severities of the nodes with seam, comparing specimens cut in bias warp and bias weft directions, was observed for the fabric D. We can make a conclusion that the difference of severities of nodes with seam and without seam depends on orthotropy of fabrics. On the other hand, orthotropy of fabrics influences the rate of asymmetry in drape behavior of a skirt. Fabric orthotropy depends on different fabric properties while testing fabrics along warp and weft directions. The higher orthotropy of fabrics D and E shows the higher difference between bending rigidities in warp and weft directions (Table II) comparing with other fabrics. But we can not say this by comparing the values of shear rigidity, because the largest difference between values of shear rigidity in bias warp and bias weft directions was observed for the fabrics C and F. Out of this fact we can make a conclusion that asymmetric drape depends on bending rigidity more then on shear rigidity of fabrics. On the other hand, shear rigidity influences fabric drape and drape profile. It can be seen from results of fabrics E and F (Table II). While bending rigidities of these fabrics are similar, drape coefficients and node numbers are different. Node number of fabric F is equal to 0 because out of large shear rigidity fabric almost does not drape on Drape meter.
Conclusions In this paper, undesirable effect of asymmetric drape near the side seam of fourgored skirt was investigated. Datas from an apparel industry survey were utilized to analyze and solve this problem. This paper also gives a methodology for the objective assessment of skirt asymmetric drape.
Figure 8. Severity of the nodes with seam and without seams: (a) specimens cut in bias warp direction, (b) specimens cut in bias weft direction
We made a conclusion that skirt asymmetric drape depends on the combination Evaluation of of grain lines directions of front and back panels of a skirt. This effect appears skirt asymmetric when sawing together front and back panels both cut in bias warp or bias weft drape direction. General conclusions were made relating skirt asymmetric drape with various fabric characteristics such as bending rigidity, extensibility, shear 297 rigidity, fabric weight and drape coefficient, in this paper. The rate of asymmetry in skirt drape behavior depends on orthotropy of fabrics, too. Relationships between various measurements of the bottom traces of a skirt of various constructions made in various sewing conditions and fabric physical and mechanical properties and fabric drape will be further examined through correlation coefficients with the aim to get a final objective evaluation of skirt asymmetric drape rate. We will work on providing a general conclusion in terms of the finding of this work, so that industry can avoid unwanted skirt drape asymmetry, too.
References Aldrich, W. (1995), Metric Pattern Cutting, Blackwell Science, Cambridge. Armstrong, H.J. (1995), Patternmaking for Fashion Design, Harper Collins Publishers, New York. Ascough, J., Bez, H.E. and Bricis, A.M. (1996), “A simple finite element model for cloth drape simulation”, Int. J. Clothing Sci. Technol., 8 No. 3, pp. 59-74. Chen, B. and Govindaraj, M. (1995), “A physically based model of fabric drape using flexible shell theory”, Textile Res. J., 65 No. 6, pp. 324-30. Chen, B. and Govindaraj, M. (1996), “A parametric study of fabric drape”, Textile Res. J., 66 No. 1, pp. 17-24. Chu, C.C., Cummings, C.L. and Teixeira, N.A. (1950), “Mechanics of elastic performance of textile materials part V: a study of the factors affecting the drape of fabrics – the development of drape meter”, Textile Res. J., 20 No. 8. Cusick, G.E. (1965), “The dependence of fabric drape on bending and shear stiffness”, J. Textile Inst., 56 No. 11, pp. T596-T606. Cusick, G.E. (1968), “The measurement of fabric drape”, J. Textile Inst., 59 No. 6. Dai, X., Furukawa, T., Mitsui, S., Takatera, M. and Shimizu, Y. (2001), “Drape formation based on geometric constraints and its application to skirt modeling”, Int. J. Clothing Sci. Technol., 13 No. 1, pp. 23-37. Gan, L. and Ly, N.G. (1995), “A study of fabric deformation using nonlinear finite elements”, Textile Res. J., 65 No. 11, pp. 660-8. House, D.H., DeVaul, R.W. and Breen, D.E. (1996), “Towards simulating cloth dynamics using interacting particles”, Int. J. Clothing Sci. Technol., 8 No. 3, pp. 75-94. Hu, J. (2000), “3D skirt simulation”, Conference IMCEP 2000, October, pp.66-72. Hu, J. and Chan, Y.F. (1998), “Effect of fabric mechanical properties on drape”, Textile Res. J., 68 No. 1, pp. 57-64. Hu, J. and Chung, S. (1998), “Drape behavior of woven fabrics with seams”, Textile Res. J., 68 No. 12, pp. 913-9.
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Hu, J. and Chung, S. (2000), “Bending behavior of woven fabrics with vertical seams”, Textile Res. J., 70 No. 2, pp. 148-53. Hu, J., Chung, S. and Lo, M. (1997), “Effect of seams on fabric drape”, Int. J. Clothing Sci. Technol., 9 No. 3, pp. 220-7. Masteikaite˙, V., Petrauskas, A., Sidabraite˙, V. and Klevaityte˙, R. (2000), “The evaluation of fabric mechanical and surface properties”, Material Science, 6 No. 2, pp. 108-12. Orzada, B.T., Moore, M.A. and Collier, B.J. (1997), “Grain alignment: effects on fabric and garment drape”, Int. J. Clothing Sci. Technol., 9 No. 4, pp. 272-84. Stylios, G.K. and Wan, T.R. (1998), “A new collision detection algorithm for garment animation”, Int. J. Clothing Sci. Technol., 10 No. 1, pp. 38-49. Stylios, G., Wan, T.R. and Powell, N.J. (1995), “Modeling the dynamic drape of fabrics on synthetic humans. A physical, lumped – parameter model”, Int. J. Clothing Sci. Technol., 7 No. 5, pp. 10-25. Stylios, G.K., Wan, T.R. and Powell, N.P. (1996), “Modeling the dynamic drape of garments on synthetic humans in a virtual fashion show”, Int. J. Clothing Sci. Technol., 8 No. 3, pp. 44-55.
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Influence of clothing material properties on rectal temperature in different environments P. Zhang and R.H. Gong
Influence of clothing material properties 299 Received April 2001 Accepted April 2002
Department of Textiles, UMIST, Manchester, UK
Y. Yanai Nisshinbo Industries, Miai Research Centre, Miai, Japan
H. Tokura Department of Environmental Health, Nara Women’s University, Japan Keywords Clothing, Physical properties, Moisture Abstract One of the main purposes of clothing is to provide the wearer protection against undesirable environments. The properties of clothing materials have critical influences on the comfort of the wearer. Also, clothing is not just a passive cover for the skin, it interacts with and modifies the heat regulating function of the skin and has effects that are modified by the environment condition. Up to the present, most physiological studies have been on the thermal regulation of the human body without clothing. Although it is a necessary first step, more realistic and valuable information can only be obtained through studies of the interaction between clothing and the physiological aspects of the human wearer. This study reports an investigation into the combined effects of the properties of the clothing material and environment conditions on the rectal temperature of human wearers. The rectal temperature was the highest for the clothing with the lower air permeability and moisture regain during both the cooling and heating periods. In the hot environment after heating, the rectal temperature was the lowest for the clothing with the higher air permeability and moisture regain in environments of both with and without wind.
Introduction Clothing comfort is an extremely complex phenomenon but it is also a very important subject for both clothing and physiological sciences. Best-Gordon (1974) attempted to relate fibre type and fabric construction to comfort, but his discussion was presented only in the most general terms. Several other authors have attempted to establish the relationship between comfort and clothing (Mehta and Narrasinham, 1987; Slater, 1977; Tarafdar, 1995). There is a general The study was conducted in collaboration with the Research Institute of Human Engineering for Quality Life (HQL), Japan and was part of the Model Project to Assemble the Human Sensory Database supported by the New Energy and Industrial Technology Development Organization (NEDO), Japan.
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agreement that the water vapour and liquid water transport rates are very important parameters of fabrics used for garments (Adler and Walsh, 1984; Happer et al., 1976). Furthermore, clothing is not only a passive cover for the skin, it interacts with and modifies the thermal regulating function of the skin and has effects that are modified by the environment. Some of this interaction is automatic, derived from the physical properties of the clothing materials and their spacing around the body. Human physiological responses are greatly influenced by the various kinds of clothing material. Ha et al. (1995) studied the effects of two kinds of clothing material, hydrophobic such as polyester and hydrophilic such as cotton, on the rate of sweating at a high ambient temperature and found that the local sweating rate was higher in polyester than in cotton. Tokura and Natsume (1987) also found that the level of rectal temperature in sedentary female was consistently higher in polyester garments than in those of wool garments at an environmental condition of 348C and 63 per cent RH. Farnworth (1986) reported that the evaporation and diffusion of water vapour through clothing system were accompanied by heat transport. The relationship between heat transfer from simulated sweating skin surface and fabric porosity was studied by Hatch et al. (1990). It was found that different moisture and air permeability of clothing material could influence internal body temperature during exercise in a hot environment. It is necessary for more data to be collected for a systematic understanding of the relationship between textile material and physiological responses. Attention will have to be paid to how clothing insulation and permeability are altered by wind speed as well as by air motion generated by wearer movement. The physical effect of wind can be more accurately measured on physical apparatus, but in clothing studies the use of living subjects to evaluate the effects of wind is essential for more realistic data. Wind is a very important factor which modifies the thermal insulation value and hence the warmth of clothing fabrics. Hollies and Goldmand (1977) described modifications to the static manikin measurement to allow for air motion and for subject generated air motion, but tests on living subjects would still be more realistic. It has been reported that wind can quickly carry away the warm air surrounding the body and act to evaporate liquid sweat and dissipate the resulting warm vapour (Watkins, 1984). Adams et al. (1992) have observed that the total body sweat loss was significantly greater in wind speeds of 0.2 m/s than 3.0 m/s and that mean skin temperature was higher in the 0.2 m/s wind speed during exercise. Havenith (1999) and Havenith et al. (1990, 1999) reported on the individual and combined effects of posture, movement, wind speed and air permeability of clothing materials on clothing insulation and ventilation. According to Nielsen et al. (1985), the combination of an increased air velocity and walking reduces air insulation when compared with walking in still air. Most studies are concerned with the influence of wind on thermal insulation, but there have been
few physiological studies on the combined effects of clothing materials and Influence of wind in different thermal environments. clothing material The present study investigates the air permeability and moisture regain of properties clothing material on the physiological responses of human subjects in environments of varying temperature and wind.
301 Methods Subjects Seven healthy female subjects participated in the study. The general purpose, procedures and risks were fully explained and informed consent was given by all the subjects. The subjects had an average age of 20.52 years (SEM 0.65), average height of 160.02 cm (SEM 1.37) and average body mass of 53.06 kg (SEM 1.98). The subjects reported to the laboratory at the same time of day to minimize circadian effects on the body temperature and they were all at the early follicular phase of their menstrual cycles. Experimental garments The experimental clothing consisted of underwear, outerwear and socks, and the shapes of these were the same for each type of clothing. The material of underwear and socks was 100 per cent cotton. Only the outerwear material was investigated in this study. Three types of clothing material were used for the outerwear. The details of these clothing materials are given in Table I. Two fibre types, cotton (Type A and Type B) and tencel (Type C), which have significant differences in moisture regain, were used. The fabrics were specially made for the study by Nisshinbo Industries in Japan. Type A and Type B were designed to have the same moisture regain but different air permeability. Type B and Type C were designed to have the same air permeability but different
Weft thickness (mm) Warp thickness (mm) Picks (cm2 1) Ends (cm2 1) Cover factor (%) Moisture regain (%) 208C 65% Moisture regain (%) 208C 90% Air permeability (cm3/cm2/s1) Air resistance (Pa/s/m1) Thermal conductivity (w/m2) Moisture transfer rate (g/m2/h1)
Type A (Cotton)
Type B (Cotton)
Type C (Tencel)
0.167 0.142 31 61 94 6.9 10.4 19 752 12 328
0.141 0.119 31 51 77 6.8 10.4 138 48 12 361
0.133 0.134 45 51 87 10.4 16.8 128 48 11 356
Table I. Details of the clothing materials
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moisture regain. Cover factor was calculated by the following formula (Lord and Mohamed, 1973): C fab ¼ ðmf df þ mw d w 2 mf d f · mw dw Þ £ 100
302
ð1Þ
where Cfab¼ fabric cover factor, mf ¼weft density, mw¼warp density, df ¼weft yarn thickness as it lies in the fabric and dw¼warp yarn thickness as it lies in the fabric. All the fabrics were subjected to the same finishing processes and were of the same light-blue colour. Apart from the air permeability and moisture regain, the design of the garments and the other physical properties of the fabrics were as closely matched as possible. Prior to the beginning of the experiment all test garments were laundered in cold and soft water and ironed. The garments were then hung in an environmentally controlled chamber for a minimum of 24 h before any test. Experimental protocol The subjects entered the artificial climatic chamber with a controlled temperature and relative humidity. The room was maintained at a constant relative humidity of 60 per cent. The room temperature was maintained at 268C in the first hour, then decreased from 268C to 208C over the course of 0.5 h. Then it was increased from 208C to 358C over the course of 1.5 h, and maintained at 358C for 2 h. In the last hour, the fan was turned on (wind velocity of 1.5 m/s when measured at chest level.) Each subject was tested with the three types of clothing, and the order was randomized. During all the experiments, the subjects sat quietly on a sofa listening to light taped music or reading books after changing their clothes. Data acquisition and analysis Rectal temperature was recorded continuously from a thermistor probe (RE type, Grant Instruments Ltd., UK, accuracy ^ 0.058C) inserted 12 cm beyond the anal sphincter and was stored every 1 min. by a Squirrel Meter Logger (type 1206) during all experiments. The data were analyzed by using a two-way factor repeated analysis of variance (environment condition and clothing type).
Results A comparison of temporal changes in the rectal temperature among the three types of clothing is shown in Figure 1. The rectal temperature decreased significantly ð p , 0:001Þ during the cooling period, then increased
Influence of clothing material properties 303
Figure 1. Rectal temperature changes
significantly ð p , 0:001Þ when the temperature rose, in conditions of both without wind and with wind. The decrease of the rectal temperature was significantly affected by the clothing type during the cooling period. The rectal temperature was higher for Type A than those for both Type B [environment condition £ clothing type; Fð59; 354Þ ¼ 2:091; p , 0:001] and Type C [environment condition £ clothing type; Fð59; 354Þ ¼ 1:956; p , 0:001]. The increase of the rectal temperature was also significantly affected by clothing type during the heating period. Again, the rectal temperature was higher for Type A than for Type B ð p , 0:01Þ and Type C ð p , 0:05Þ: In the hot environment without wind, there were significant differences in the increase of the rectal temperature between Type A and Type B [environment condition £ clothing type; Fð59; 354Þ ¼ 1:82; p , 0:001], and between Type A and Type C [environment condition £ clothing type; Fð59; 354Þ ¼ 2:454; p , 0:001]. Compared to Type C, the rectal temperatures were higher ð p , 0:1Þ for both Type A and Type B. The same trend exists in the hot environment with wind. The rectal temperature for Type C was lower ð p , 0:05Þ than both Type A and Type B.
Discussions The body can be regarded as an internal combustion engine. In a temperate climate, the resting internal body temperature is maintained between about 35.6 and 37.28C by the “thermostat” at the base of the brain; this maintains a balance between heat production and heat loss. The present study evaluated
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the effect of the clothing material on the rectal temperature in different environments. It was shown that when chemical protective clothing was worn in the cold, the extremities were especially susceptible to cooling (Cortili et al., 1996; Rissanen and Rintama¨ki, 1997), and systolic and diastolic blood pressure increased (Gavhed et al., 2000). Furthermore, it has been shown that the torso skin temperature increased gradually after the first session during four consecutive exercise/rest sessions in the cold (Rissanen and Rintama¨ki, 1998). In our experiment, the rectal temperature decreased dramatically when cooling began, but became steady after about 30 min. The body heat is dissipated at the body surface as latent heat derived from insensible perspiration which is continually passing out through the skin; the rest of the heat is lost by radiation and convection at the surface of the clothing. As seen in Figure 1, the rectal temperature for Type A clothing was the highest. This indicates that when this clothing was worn, the lowest heat flow occurred from the skin surface through the clothing to the surrounding air during both the cooling and heating periods. This is likely to be caused by the least heat exchange by evaporative and dry heat flow for Type A because it has the lowest air permeability of the three clothing materials. When the air temperature is higher than the skin temperature, heat can no longer be lost by convection or radiation and cooling of the body depends entirely on the evaporation of sweat. Although a freely perspiring body clothed by dry fabric may lose more heat, the rate of evaporation from the body varies in proportion to the moisture regain of the clothing when the clothing is damp. When sweat production increases under the hot condition, the water-drops accumulated on the fabric surface and its inside could be occupying the space in the fabric for moisture absorption. The moisture absorption of fabrics depends on the moisture regain of the fibers and on the environmental conditions (Fourt and Hollies, 1970). In this study, Type C was made from tencel and has a higher moisture regain. It takes up relatively larger quantities of liquid water; this can be an advantage for removing sweat from the skin and results in the lowest rectal temperature after heating in both the environments of with and without wind.
Conclusions When the environmental temperature is lower than the skin temperature, the air permeability of clothing materials has a far greater influence than the moisture regain on the rectal temperature of the human wearer. This is because a higher air permeability allows greater dry heat loss through convection and radiation. However, when the body has to lose heat through the evaporation of perspiration, for example in an environment where the temperature is higher than the skin temperature, the moisture regain becomes important as well.
A higher moisture regain allows better sweat removal from the skin and more Influence of effective wet heat loss through evaporation, resulting in lower rectal clothing material temperature of the wearer. This appears to be true whether or not there is properties wind, although the influence of moisture regain tends to be increased by wind. References Adams, W.C., Gray, W.M., Gray, W.L. and Ethan, R.N. (1992), “Effects of varied air velocity on sweating and evaporative rates during exercise”, J. Appl. Physiol., 73, pp. 2668-74. Adler, M.M. and Walsh, W.K. (1984), “Mechanisms of transient moisture transport between fabrics”, Text. Res. J., 54, pp. 334-43. Best-Gordon, H. (1974), “The ‘natural’ choice for a come-back?”, Textile Month, p. 95 Cortili, G., Mognoni, P. and Saibene, F. (1996), “Work tolerance and physilogical responses to thermal environment wearing protective NBC clothing”, Ergonomics, 4, pp. 620-33. Farnworth, B. (1986), “A numerical model of the combined diffusion of heat and water vapor through clothing”, Text. Res. J., 56, pp. 653-65. Fourt, L. and Hollies, N.R.S. (1970), Clothing: Comfort and Function, Marcel Dekker, New York. Gavhed, D., Ma¨kinen, T., Holme´r, I. and Rintama¨ki, H. (2000), “Face temperature and cardiorespiratory responses to wind in thermoneutral and cool subjects exposed to 2 108C”, Eur. J. Appl. Physiol., 83, pp. 449-56. Ha, M., Tokura, H. and Yamashita, Y. (1995), “Effect of two kinds of clothing made from hydrophobic and hydrophilic fabrics on local sweating rates at an ambient temperature of 378C”, Ergonomics, 38, pp. 1445-55. Happer, R.J., Bruno, J.S., Blanchard, E.J. and Gautreaux, G.A. (1976), “Moisture-related properties of cotton-polyester blend fabrics”, Text. Res. J., 46, pp. 82-90. Hatch, K.L., Markee, N.L., Maibach, H.I., Barker, R.L., Woo, S.S. and Radhakrishnaiah, P. (1990), “In vivo cutaneous and perceived comfort response to fabric, III. Water content and blood flow in human skin under garments worn by exercising subjects in a hot, humid environment”, Text. Res. J., 60, pp. 511-9. Havenith, G. (1999), “Heat balance when wearing protective clothing”, Ann. Occup. Hyg., 43, pp. 289-96. Havenith, G., Heus, R. and Lotens, W.A. (1990), “Resultant clothing insulation: a function of body movement, posture, wind, clothing fit and ensemble thickness”, Ergonomics, 33, pp. 67-84. Havenith, G., Holmer, I., Den Hartog, E.A. and Parsons, K.C. (1999), “Clothing evaporative heat resistance-proposal for improved representation in standards and models”, Ann. Occup. Hyg., 43, pp. 339-46. Hollies, N.R.S. and Goldmand, R.F. (1977), Clothing Comfort: Interaction of Thermal, Ventilation, Construction and Assessment Factors, Ann Arbor Science, Ann Arbor, Michigan. Lord, P.R. and Mohamed, M.H. (1973), Weaving: Conversion of Yarn to Fabric, Merrow Technical Library. Mehta, R. and Narrasinham, K.V. (1987), “Clothing comfort – A review of related properties”, Man-made Textile in India, 30, pp. 327-35. Nielsen, R., Olesen, B.W. and Fanger, P.O. (1985), “Effects of physical activity and air velocity on the thermal insulation of clothing”, Ergonomics, 28, pp. 1617-32. Rissanen, S. and Rintama¨ ki, H. (1997), “Thermal responses and physiological strain in men wearing impermeable and semipermeable protective clothing in the cold”, Ergonomics, 40, pp. 141-50.
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Rissanen, S. and Rintama¨ki, H. (1998), “Effects of repeated exercise/rest sessions at 2108C on skin and rectal temperatures in men wearing chemical protective clothing”, Eur. J. Appl. Physiol., 78, pp. 560-4. Slater, K. (1977), “Comfort properties of textiles”, Textile Progress, 9 No. 4, pp. 1-91. Tarafdar, N. (1995), “Selection of appropriate clothing in relation to garment comfort”, Man-made Textiles in India, 38 No. 1, pp. 17-21. Tokura, H. and Natsume, K. (1987), “The effects of different clothing on human thermoregulation at an ambient temperature of 348C”, Trans Menzies Foundation, 14, pp. 279-81. Watkins, S.M. (1984), Clothing: The Portable Environment, Iowa State University Press, Ames, Iowa, pp. 3-57.
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Garment’s pressure sensation (1): subjective assessment and predictability for the sensation
Garment’s pressure sensation 307
F. You, J.M. Wang and X.N. Luo Compute Application Graduate School, Zhongshan University, People’s Republic of China
Y. Li
Received March 2001 Revised May 2002 Accepted May 2002
Institute of Textile and Clothing, The Hong Kong Polytechnic University
X. Zhang Clothing Department, Xian Institute of Science and Technology, People’s Republic of China Keywords Factor analysis, Garments, Fabric, Subjectivity Abstract In order to study the wearing comfort of pressure for tight-fit clothing, the sensation of wearing pressure and the other related sensations have been assessed for knit garments, which have different sizes and fabrics which have different extensibilities, by developing a wearing experimental procedure. Using factor analysis with principal factor solutions and rotated by the Varimax method, we obtained relevant factor matrices about the subjective assessment. At the same time, objective clothing pressure, fabric extensibility and garment fitness have been measured. Regression analysis showed that the garment fitness and fabric extensibility had great predictive power for the subjective pressure assessment.
1. Introduction Comfort of clothing is the psychological feeling or judgment of a wearer who wears the clothing under certain environmental conditions. Garments’ wearing comfort cannot be described comprehensively using purely physical parameters, although many objective properties of fabrics and garments are related to garments’ wearing comfort. Subjective assessment is a complex synthesis of many kinds of psychological and physiological response of individuals and of the physical properties of the clothing materials. Therefore, subjective measurement is critical for the assessment of clothing comfort (Li, 1998; Li et al., 1991). Wearing comfort of pressure is a major direction for study of wearing comfort, and the pressure wearing comfort is basically determined by the extensibility of fabrics, the fitness of garments and the style of garments. The pressure comfort is one of the most important factors influencing a wearer’s sensation of comfort in tight-fitting garments. Therefore, we developed a wearing experimental procedure and investigated the
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relationship between different subjective wearing sensations using factor analysis. At the same time, regression analysis showed that garments’ fitness and fabrics’ extensibility have great predictive power for the subjective measurement of pressure when garments’ style remains the same. 2. Experimental 2.1. Fabric material and garment size Nine tight-fit pants were made from three knit fabrics with different extensibilities. Three pairs of pants of different sizes(s, m, l) were made from each fabric. The style of the resulting nine garments were the same, and the grading between different sizes(s, m, l) were the same, as shown in Table I and Figure 1. According to the model of using membrane theory to analyze the stress distributions of fabrics (Zhang et al., 2000a, b), the extensibility of fabrics has the main contribution to the garment pressure. Figures 2 and 3 show the extensibility of three fabrics in warp and wept directions. The fitness of the garments was defined in the following way: The fitness of garment ¼ ðthe girth of garment 2 the girth of the naked bodyÞ=the girth of the naked body
Table I. Fabrics and garments
Figure 1. The grading between different sizes(s, m, l)
Fabric ID
Fabric weave
Fiber content %
a b c
Double jersey Double jersey Tricot
Dacron 100% Spandex 5%/Cotton 95% Spandex 20%/Nylon 80%
Garment size s, m, l s, m, l s, m, l
2.2. Wearer trials Subjects were 18 female textile college students chosen among 400 students within the age range of 18-25 years. Details of physical constitutions are given in Table II. Every subject was required to wear appointed four tight-fitting pairs of pants selected from nine pairs. Finally, every pair would be evaluated eight times by the different subject, without a time limitation in a quiet room maintained at a temperature of 208C and a relative humidity of 60 per cent. Each trial consisted of two conditions: stand and raise a leg (with 908 between the thigh and shank, and with the thigh parallel to the ground).
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2.3. Measurement of the clothing pressure and fabric strain A sensor (You, 2000) was used to measure clothing pressure, and four areas of body were selected upon which the pressure according to the strain areas of the body was measured. GYG-06 pressure Sensor was primarily designed to measure the application in which the pressure range can be expected to be 0-10 kPa. The size of sensor cell was 10 £ 10 mm; and no more than 5 mm high. The sensor cell was small and flexible, and so could be easily inserted between the pants and skin without affecting the accuracy of the pressure measurement. The hip (area 1, at the level of hip girth), the shank (area 2, L1cm below the back of the center of the knee cap, L1 – the length between the center of knee cap and anklebone), the thigh (area 3, L2cm above the center of knee cap – the length between the center of knee cap and hipbone) and the knee (area 4, the center of knee cap) were selected upon which the clothing pressure on the body
Figure 2. The extensibility of fabric in warp direction(y:kg; x:%)
Figure 3. The extensibility of fabric in wept direction(y:kg; x:%)
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Table II. Physical constitution of subjects
Maximum Thigh Anterior Height waist height Knee height Waist girth Hip girth base girth shank girth (cm) (cm) (cm) (cm) (cm) (cm) Subject (cm) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
163 159 159.5 160 161 161.5 161.5 162 162 162.1 162.5 163 163 163 163.5 163.5 164 165
103 102.5 102 101 102.5 101 101 101.5 102 103.5 100.5 104 104 104.5 101.5 105 101.5 100.5
46 45.5 46.5 42.5 45.5 45.5 43 43 44 46 47 47.5 45 47.5 46 45 44.5 48
63 64.5 62.5 65.5 64 63 63 63 65 65 62.5 62.5 63 65 63 63.5 63 61.5
90 88 89 90.5 87 87.5 90 88 89.5 87 91 88.5 90 90 87 91 88 89
52 49 50 50.5 50 51 52 54 52 50.5 49 51 50.5 51 50.5 53.5 53 52
35 33.5 34 33.5 34.5 33.5 34.5 36.5 35 35 32 34 34 36 32 34.5 34 36
was measured. The sensor was put to the four parts between clothing and body to measure clothing pressure. Four strain around the four areas just mentioned was also measured. This was done by drawing a series of lines on the thigh-fit at regular intervals and measuring the changes in dimension that took place when subjects were wearing the garment. Figures 4 and 5 show the measuring areas and method.
2.4. Subjective assessment Magnitude estimation (Marks, 1974), a simple and generally applicable method of psychophysical scaling for a quantitative continuum, was used in rating
Figure 4. Measuring points
Garment’s pressure sensation 311 Figure 5. Measuring method
subjective perception. We use it to assess pressure perception and other relative wearing sensations in our wearer trials by psychophysical scaling. Subjects were asked to rate the sense of pressure on a scale of 0-10. One tight-fitting pair of pants with a great clothing pressure was presented to subjects as the standard for the maximum degree of pressure, indexed as 10. And when subjects were naked, this was presented as the standard for the minimum degree of pressure, indexed as 0. The subjects were asked to rate the sense on a scale 0-10. Every subject was asked to assess the pressure sensation of each area while wearing the garments. Because subjective assessment is a complex synthesis of many kinds of psychological and physiological response of individuals, the subjective responses of wearers are not only decided by the physical properties of garments but also by the wearing habits and experiences of wearers. Therefore, questionnaire design is critical for the rating of subjective sensations. The other adjectives used were also rated on a similar scale. Such adjectives included: fetter, smooth, scratchy, soft, heavy and pressure comfort. Some questions about habits and experiences of subjects were also asked, such as: how often do you wear tight-fitting garments?; average number of tight-fitting garments worn per week?; where did you live before going to college? 3. Result 3.1. Relationship between different subjective wearing sensations Table III shows the correlation coefficients for every subject’s rating scores of each adjective. From them, we see that the wearing comfort of pressure has a negative correlation with the feeling of fetter, scratchy, heavy and the sensation of pressure, and that the sensation of pressure has a positive correlation with the feeling of fetter, scratchy and heavy. We obtained factor matrices using principal factor solutions, which constitute the proportion of the test variances ascribed to the actions of the common factors. Using factor analysis, five factors were extracted from seven
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adjectives, whose numeric features and accumulated percentage contributions are shown in Table IV. After rotating the factor axes, the structure of the sensory test relations was more clearly indicated. The results of factor matrices rotated by the Varimax method are shown in Table V. The five factors obtained are given in Table V. In this case, five factors were sufficient to describe the data. Each column of the factor loading must be studied in turn so that the nature of each factor can be determined. As shown in Table V, factor One is highly related to the sensation of pressure, the pressure wearing comfort and the feeling of fetter. Factor Two is highly related to garments that have scratchy feeling and factor Three to those garments that feels heavy. Factor Four is highly related to the feeling of softness and Factor five to the feeling of smoothness. According to results of the above analysis with the knowledge of factor analysis, when wearing tight-fitting garments, the sensation of pressure, the wearing comfort of pressure and the feeling of fetter can be explained by the common factor (factor One), which mainly reflect the fitness of garment, because these three adjectives are highly related to factor One. But the other feelings (scratchy, heavy, soft, smooth) cannot be explained by any common factor, that is they do not have natural relations to one another.
Correlation Table III. Correlation coefficients of sensory values for each adjective correlation matrix
Pressure comfort Pressure sensation Fetter Heavy Scratchy Smoothness
Component Total
Table IV. Total variance explained
1 2 3 4 5 6 7
3.434 1.402 0.905 0.432 0.347 0.320 0.160
Pressure sensation
Fetter
Heavy
2 0.683
2 0.792 0.675
2 0.458 0.342 0.444
Initial eigenvalues % of variance Cumulative % 49.054 20.031 12.935 6.169 4.956 4.576 2.279
49.054 69.085 82.020 88.189 93.146 97.721 100.000
Scratchy Smoothness 2 0.510 0.436 0.605 0.642
0.157 2 0.100 2 0.012 2 0.366 2 0.248
Soft 0.247 2 0.218 2 0.224 2 0.201 2 0.116 0.511
Extraction sums of squared loadings Total % of variance Cumulative % 3.343 1.402 0.905 0.432 0.347
Note: Extraction method: principal component analysis.
49.054 20.031 12.935 6.169 4.956
49.054 69.085 82.020 88.189 93.146
Pressure comfort Pressure sensation Fetter Heavy Scratchy Smoothness Soft
Component 3
1
2
2 0.842
2 0.190
0.920 0.767 0.236 0.317 2 1.42 £ 102 2 2 0.144
9.177 £ 102 2 0.439 0.293 0.872 2 9.87 £ 102 2 2 8.10 £ 102 3
Garment’s pressure sensation
4
5
2 0.263
0.148
5.952 £ 102 3
3.949 £ 102 2 0.186 0.898 0.312 2 0.173 2 5.00 £ 102 2
5.916 £ 102 5 2 0.203 2 5.98 £ 102 2 1.093 £ 102 2 0.291 0.939
2 0.138 0.199 2 0.190 2 0.144 0.918 0.275
Notes: Extraction method: principal component analysis; Rotation method: Varimax with kaiser normalization; a Rotation converged in 7 iterations.
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Table V. Rotated component matrixa
3.2. Relationship between clothing pressure and fabrics strain Clothing pressure is not only dependent on fabric extensibility and fabric stretch levels, but also on the curvature of skin (Ito, 1995). So, body’s four areas were measured and analyzed individually. The knee area will be explained here as an example. Clothing pressure and fabric strain were measured and analyzed while subjects were wearing garments of different fits and fabrics; regression equations in the knee area with regard to clothing pressure and fabric strain were obtained, and are shown in Table VI. Figures 6 and 7 show the relationships of clothing pressure and fabric strain in warp and wept directions. Regular pattern of curves was found between Figures 1, 2 and Figures 5, 6. This means that clothing pressure increases with fabric extensibility when the fabric strain remains the same. Therefore, clothing pressure is not only related to fabric strain, but also to fabric extensibility.
Direction
Fabrics
Warp
a b c a b c
Wept
Notes: y: Fabric strain; x: Clothing pressure.
Equation y¼ y¼ y¼ y¼ y¼ y¼
2 58.13+8.24 ln(x ) 2 99.59+14.24 ln(x ) 2 237.52+32.60 ln(x ) 2 32.37+6.70 ln(x ) 2 116.95+19.62 ln(x ) 2 139.65+21.45 ln(x )
R R ¼ 0.90 R ¼ 0.89 R ¼ 0.74 R ¼ 0.74 R ¼ 0.94 R ¼ 0.91
Table VI. Regression equations of clothing pressure and fabrics strains
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314 Figure 6. Relationship of clothing pressure and fabric strain in warp direction y: fabrics strain (%); x: clothing pressure
Figure 7. Relationship between clothing pressure and fabric strain in wept direction y: fabrics strain (%); x: clothing pressure (Pa)
There are similar results in other body when the same procedure was applied. Therefore, fabric extensibility should be one important quota of the physical properties of clothing materials in the study of clothing pressure.
3.3. Relationship between pressure sensation and garment fit Refined garment fit has been given and it reflects the original fit between the garment and the body without the influence of fabric extensibility. The Fit 1 (Fit 1¼ 2Fit) was used to describe the fit of garments in this study, since the fit of tight clothing is frequently expressed by a negative number. The regression equations between Fitness 1 and pressure sensation are
shown in Table VII that illustrates this phenomenon in the knee area when subjects are wearing garments under standing conditions. The analysis shows that garment fit has a high relation to pressure sensations for three fabrics when subjects are wearing tight clothing under standing conditions. Therefore, garment fit should be considered as a quota in the study of clothing pressure comfort.
Garment’s pressure sensation 315
3.4. Predictability of pressure sensation by garment fit and fabric extensibility Liner regression analysis showed that variables for the fit of garments and the extensibility of fabrics are good predictors for subjective pressure assessment ðR . 0:9Þ: Regression equations are shown in Table VIII.
4. Discussion The major cause of clothing pressure is garment resistance to the body’s demands, especially with regards to the reduction of garment fit and increasing body motion. The critical strain areas of the body in motion would produce fabric stretch, and then the subject’s sensation of wearing pressure would result. Figures 6 and 7 show fabric degree of change in the warp and wept directions for the knee area. Fabric a has about 20 per cent stretch level, fabric b about 35 per cent, and fabric c about 55 per cent in the warp direction; fabric a has about 40 per cent, fabric b about 60 per cent, and fabric c about 55 per cent in the wept direction. But in fact, the skin stretch in the warp direction is higher
Fabrics a b c
Equations
R
y ¼ 14.66+3.51 ln(x ) y ¼ 16.78+5.79 ln(x ) y ¼ 17.90+7.07 ln(x )
0.96 0.93 0.89
Notes: y: Pressure sensation; x: Fitness 1.
Areas Hip Knee Shank Thigh
Equations y¼ y¼ y¼ y¼
2 1.19+35.19x1+1.29x2+15.83x3 2 0.99+34.33x1+3.38x2+0.77x3 2 4.24+33.74x1+4.24x2+1.86x3 2 5.80+50.22x1+0.98x2+16.82x3
Table VII. Regression equations of fitness 1 and pressure sensation
R R¼ 0.94 R¼ 0.94 R¼ 0.90 R¼ 0.92
Notes: y: Pressure sensation; x1: Fitness 1; x2: Fabric extensibility in warp; x3: Fabric extensibility in wept.
Table VIII. Predictive equations for pressure sensation
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than in the wept direction when we raise ours legs. The slip between the fabric and the skin is a major cause leading to great stretch differences for the fabric and skin in two directions. Fabric extensibility also affects fabric stretch in any direction. Figures 2 and 3 show that the extensibility of fabric a and fabric b in the warp direction are considerably higher than in the wept direction. So, fabrics a and b are easier to extend in wept than in warp. Fabric c’s warp and wept extension are similar. Fabric extensibility is highly related to fabric stretch in wearing. Therefore, we should not only pay attention to fabric extensibility in the warp direction but also in the wept direction with regard to the production of tensioned pants. Regression analysis showed that fabric extensibility and garment fit have good predictive power with regard to wearing pressure sensations when subjects are standing under certain conditions. Table VIII showed that if we want to maintain wearing pressure comfort, the tightness should have garment fit and the fabric extensibility, or either of them. 5. Conclusion The wearing comfort of pressure has a negative correlation with the feeling of fetter, scratchy, heavy and the sensation of pressure, and has a poor correlation with the feeling of softness and smoothness. The proportions of pressure sensation, wearing comfort of pressure and fettered feelings can be explained by the common factor: the garment’s fit. And the other feelings, such as scratchy, heavy, softness and smoothness, do not have natural relations to one another. In this study, the garment fit and the fabric extensibility show good ability to predict pressure sensation for clothing, when garments have the same style and the skin stretch of subjects is not high. References Ito, Noriko (1995), “Clothing pressure”, Jpn. Res. Assn. Text. End-Uses, 36 No. 1, pp. 38-43. Li, Yi (1998), “Clothing comfort and its application”, Textile Asia, pp. 29-33. Li, Y., Keighley, J.H., Mcintyre, J.E. and Hampton, I.F.G. (1991), “Predictability between objective physical factors of fabrics and subjective preference votes for derived garments”, J. Text. Inst., 82 No. 3, pp. 277-84. Marks, Lawrence E. (1974), Sensory Processes, Academic Press, New York and London. You, F. (2000), “The pressure comfort of tight-fit clothing”, Master thesis. Zhang, X., Li, Y., Yeung, K.W., Miao, M.H. and Yao, M. (2000a), “Fabric – bagging : stress distribution in isotropic and anisotropic fabrics”, J. Text. Inst., 91 No. 4, pp. 563-76. Zhang, X., Li, Y., Yeung, K.W., Miao, M.H. and Yao, M. (2000b), “Mathematical simulation of fabric bagging”, Textile Res. J., 70 No. 1, pp. 18-28.
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Garment’s pressure sensation (2): the psychophysical mechanism for the sensation
Garment’s pressure sensation 317
F. You, J.M. Wang and X.N. Luo Compute Application Graduate School, Zhongshan University
Y. Li Institute of Textile and Clothing, The Hong Kong Polytechnic University
X. Zhang Clothing Department, Xian Institute of Science and Technology Keywords Physical properties, Subjectivity, Clothing, Factor analysis Abstract Relationships have been investigated between subjective pressure sensation and objective pressure measured, for knit garments of different sizes and fabrics with different extensibilities. Fechner’s logarithmic law is used to investigate the relations. Equations are obtained for describing the Psychophysical mechanism of clothing pressure perception under certain conditions. Objective pressure measuring had high predictive power with regard to subjective pressure sensation only under those conditions. Wearing pressure comfort has a negative correlation with feelings of fetter, scratchy, heavy and pressure, and has a poor correlation with feelings of softness and smoothness. Using factor analysis with principal factor solutions and rotated by the Varimax method, we obtained factor matrices.
1. Introduction The subjective assessment of pressure is one of the most important factors influencing a wearer’s sensation of comfort in tight-fitting garments. Some work (Haruko Makabe et al., 1991; Harumi Morooka et al., 1997; Kazuya Sasaki et al., 1997; Noriko Ito et al., 1995) has been carried out in the area of clothing pressure and wearing comfort. Haruko Makabe et al. (1991) and Kazuya Sasaki et al. (1997) studied and discussed the relation between comfort and clothing pressure. Harumi Morooka et al. (1997) and Noriko Ito et al. (1995) investigated the relationship between physical fabric properties and the wearing comfort of girdles. Generally, people think clothing pressure is the only reason leading to pressure perception. So, other reasons were seldom analyzed and studied. However, the published literature lacks of publications on the process and mechanisms of clothing pressure perception. In this report, we develop a psychophysical experimental procedure for wearing pressure comfort. Based on a series of studies of subjective responses in a wearer trial and objective measurements of pressure between garment and skin, equations between subjective sensation and objective
International Journal of Clothing Science and Technology, Vol. 14 No. 5, 2002, pp. 317-327. q MCB UP Limited, 0955-6222 DOI 10.1108/09556220210446248
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pressure measured have been obtained using the psychophysical law under certain conditions. The correlation between wearing pressure comfort, the pressure sensation, the feeling of fetter, scratchy, heavy, soft and smoothness are investigated by means of factor analysis with principal factor solutions.
318 2. Experimental 2.1. Fabric material and garment fit Tight-fit pants were made from three knit fabrics with different extensibilities. Three pair of pants of different sizes (s, m, l) were made from each fabric. The styles of the nine garments were the same, as shown in Table I. 2.2. Wearer trials Subjects were 18 female textile college students chosen among 400 students within the age range of 18-25 years. Details of physical constitutions are given in Table II. Every subject was required to wear four tight-fitting pair of pants, selected from nine pairs. Finally, every pair of pants would be evaluated eight times by each subject, without time limitation and in a quiet room maintained at a temperature of 208C and a relative humidity of 60 per cent. Each trial consisted of two conditions: stand and raise a leg (with 908 between thigh and shank, and with the thigh parallel to the ground) Each subject was required to answer the survey questionnaire in each condition, and at the same time, pressures of clothing to the body were measured. 2.3. Measurement of clothing pressure A sensor was used to measure clothing pressure, and four areas of the body were selected for measuring pressure according to the strain areas of the body under two conditions(standing and raised leg). The hip (area 1,at the level of hip girth), the shank (area 2, 18 cm below the back of the center of the knee cap), the thigh (area 3, 16 cm above the center of the knee cap) and the knee (area 4, the center of knee cap) were selected in
Table I. Fabrics and garments
Fabric ID
Fabric weave
Fiber content %
a b c
Double jersey Double jersey Tricot
Dacron 100% Spandex 5%/Cotton 95% Spandex 20%/Nylon 80%
Garment size s, m, l s, m, l s, m, l
Height Subject (cm) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
163 159 159.5 160 161 161.5 161.5 162 162 162.1 162.5 163 163 163 163.5 163.5 164 165
Anterior waist height (cm)
Knee height (cm)
Waist girth (cm)
Hip girth (cm)
Thigh base girth (cm)
Maximum shank girth (cm)
103 102.5 102 101 102.5 101 101 101.5 102 103.5 100.5 104 104 104.5 101.5 105 101.5 100.5
46 45.5 46.5 42.5 45.5 45.5 43 43 44 46 47 47.5 45 47.5 46 45 44.5 48
63 64.5 62.5 65.5 64 63 63 63 65 65 62.5 62.5 63 65 63 63.5 63 61.5
90 88 89 90.5 87 87.5 90 88 89.5 87 91 88.5 90 90 87 91 88 89
52 49 50 50.5 50 51 52 54 52 50.5 49 51 50.5 51 50.5 53.5 53 52
35 33.5 34 33.5 34.5 33.5 34.5 36.5 35 35 32 34 34 36 32 34.5 34 36
Garment’s pressure sensation 319
Table II. Physical constitution of subjects
which the pressure of clothing to the body was measured. Figure 1 shows these measuring points under two conditions. 2.4. Subjective assessment Magnitude estimation, a simple and generally applicable method in the psychophysical scaling method for a quantitative continuum, was used in rating subjective perception. The subjects were asked to rate the sense of pressure on a scale of 0-10. A pair of tight-fitting pants with great clothing pressure was presented to subjects as the standard for the maximum degree
Figure 1. Measuring points under two conditions
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of pressure, indexed as 10. And when subjects were naked, this was presented as the standard for the minimum degree of pressure, indexed as 0. Other adjectives were also rated on a similar scale: fetter, smooth, scratchy, soft, heavy, pressure comfort. Some questions about the habit of subjects were also asked, such as: how often do you wear tight-fitting garments? Average number of tight-fitting garments worn per week?
3. Results 3.1. Relationship between subjective sensation and objective pressure measured Every subject’s magnitude estimations of subjective pressure sensation and objective pressure obtained in the wearer trials were recorded. The relationship between pressure sensation and measured pressure is shown in Figure 2. Data was derived from subjects who wore garments of different fabrics and different sizes under two different conditions (standing and raised leg). A logarithmic relation between pressure sensation and measured pressure were observed. The objective pressure measured contributes to 58 (hip), 42 (knee), 64 (shank) and 52 per cent (thigh) of the total variance in the subjective rating, indicating that objective pressure measured has predictive power with regard to subjective pressure sensation in some degree. We divided every set of data into three groups according to the fabrics used, providing the equations and their R were not changed too much. The results are shown in Figure 3. So, fabrics are not the main factor in the relation between pressure sensation and measured pressure. Thus we divided the data provided by the fabrics, into two again, according to the body’s condition (standing and raised leg). It was found that objective pressure measured had a strong predictive power with regard to subjective pressure sensation. Figure 4 shows the relationships between pressure sensation and measured pressure in the hip area with fabric A. Subjective ratings are highly correlated with corresponding clothing pressures. In different body areas with different fabrics under standing conditions, clothing pressure contributes to about 90 per cent of total variance in the subjective rating under standing conditions, but only 70-80 per cent under raised leg condition. Fechner’s logarithmic law R ¼ a þ b log S are fitted to the data under standing conditions, where R is the sensation magnitude, S is the stimulus magnitude, and a is the constant. The value of exponent b reflects future sensory continuum, which differs from one sensory continuum to another. Only when skin strain is minimum and the fabric is the same, does clothing pressure have a good predictive power with regard to subjective pressure sensation in the same body area. Equations are also obtained for describing the psychophysical mechanism of clothing pressure perception under this condition.
Garment’s pressure sensation 321
(Continued)
Figure 2. The relationships between pressure sensation and measured pressure in different body areas
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Figure 2.
3.2. The analysis of subjective assessment Table III shows the correlation coefficients for every subject’s rating scores of each adjective. From them, we see that wearing pressure comfort has a negative correlation with the feeling of fetter, scratchy, heavy and the sensation of pressure; the sensation of pressure has a positive correlation with the feeling of fetter, scratchy and heavy. We obtained factor matrices using principal factor solutions, which constitute the proportion of the test variance ascribed to the action of the common factors. Using factor analysis, five factors were extracted from seven adjectives, whose numeric features and percentages of accumulated contribution are shown in Table IV. After rotating the factor axes, the structure of the sensory test relations was more clearly indicated. The results of factor matrices rotated by the Varimax method are shown in Table V. The five factors obtained are given in Table V. In this case, five factors were sufficient to describe the data. Each column of the factor loading must be studied in turn so that the nature of each factor can be determined. As shown in Table V, factor One is highly related to the sensation of pressure, wearing pressure comfort and the feeling of fetter. Factor Two is highly related to garments that have scratchy feeling and factor Three to those garments that feels heavy. Factor Four is highly related to the feeling of softness and factor Five to the feeling of smoothness.
Garment’s pressure sensation 323
Figure 3. The relationships between pressure sensation and measured pressure in the hip area with different fabrics (Continued)
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Figure 3.
Garment’s pressure sensation 325
Figure 4. The relationships between pressure sensation and measured pressure in the hip area with fabric A under certain conditions
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According to the results of the above analysis, when we wear tight-fitting garments, the sensation of pressure, wearing pressure comfort and the feeling of fetter could be explained by the common factor (factor One), which mainly reflects the fit of the garment. But the other feelings (scratchy, heavy, soft, smooth) could not be explained by any common factor, that is, the other feelings have no natural relation to each other.
Correlation Table III. Correlation coefficients of sensory values for each adjective correlation matrix
Pressure comfort Pressure sensation Fetter Heavy Scratchy Smoothness
Component
Table IV. Total variance explained
Pressure sensation
Total
2 0.683
Heavy
20.792 2 0.458 0.675 0.342 0.444
Initial eigenvalues % of Variance Cumulative %
2
Scratchy Smoothness 2 0.510 0.436 0.605 0.642
0.157 2 0.100 2 0.012 2 0.366 2 0.248
Soft 0.247 2 0.218 2 0.224 2 0.201 2 0.116 0.511
Extraction sums of squared loadings Total % of Variance Cumulative %
1 3.434 49.054 49.054 3.434 2 1.402 20.031 69.085 1.402 3 0.905 12.935 82.020 0.905 4 0.432 6.169 88.189 0.432 5 0.347 4.956 93.146 0.347 6 0.320 4.576 97.721 7 0.160 2.279 100.000 Note: Extraction method: principal component analysis.
1
Table V. Rotated component matrixa
Fetter
Component 3
49.054 20.031 12.935 6.169 4.956
4
49.054 69.085 82.020 88.189 93.146
5
Pressure comfort 2 0.842 20.190 2 0.263 0.148 5.952 £ 102 3 Pressure sensation 0.920 9.177 £ 102 2 3.949 £ 102 2 5.916 £ 102 5 2 0.138 Fetter 0.767 0.439 0.186 20.203 0.199 Heavy 0.236 0.293 0.898 2 5.98 £ 102 2 2 0.190 Scratchy 0.317 0.872 0.312 1.093 £ 102 2 2 0.144 Smoothness 21.42 £ 102 2 2 9.87 £ 102 2 2 0.173 0.291 0.918 Soft 2 0.144 2 8.10 £ 102 3 25.00 £ 102 2 0.939 0.275 Note: Extraction method: principal component analysis; Rotation method: Varimax with kaiser normalization; a Rotation converged in 7 iterations.
4. Discussion Generally, people think clothing pressure is the only reason leading to pressure perception. So, other reasons have seldom been analyzed and studied. Based on a series of studies of subjective responses in wearer trials and objective measurements of pressure under different conditions, we found that subjective pressure sensation is not only decided by the objective clothing condition but also by skin strain, even if garments are made of the same fabric. Equations between subjective sensation and objective pressure measured were obtained here using the psychophysical law under certain conditions. We obtained an equation describing the psychophysical mechanism of clothing pressure perception in which clothing pressure served as stimulation, because skin strain was minimal. On the contrary, an equation cannot be obtained when skin strain increases with regard to the movement of critical strain areas of the body, such as knee, hip, back and elbows. This conclusion is consistent with the psychological view that real stimulation of a pressure sensation is not physical pressure but skin strain. This conclusion also tells us that we should not only study clothing pressure vis-a-vis wearing pressure comfort, but also precision skin strain in three dimensions, especially when studying dynamic clothing pressure. 5. Conclusion In this study, Fechner’s logarithmic law was used to explain the psychophysical mechanism of clothing pressure perception. Objective pressure measured had high predictive power with regard to subjective pressure sensation only under some special conditions. Wearing pressure comfort has a negative correlation with the feeling of fetter, scratchy, heavy and the sensation of pressure, and has a poor correlation with the feeling of softness and of smoothness. The proportions of pressure sensation, wearing pressure comfort and feeling fettered could be explained by a common factor: the fit of garment. The other feelings, such as scratchiness, heaviness, softness and smoothness do not have any natural relation with each other. References Haruko, Makabe, Hiroko, Momota, Tamaki, Mitsuno and Kazuo, Ueda (1991), “A study of clothing pressure developed by the girdle”, Jpn. Res. Assn. Text. End-Uses, 32, pp. 42-56. Harumi, Morooka, Miyuki, Nakahashi and Hideo, Morooka (1997), Jpn. Res. Assn. Text. EndUses, 38, pp. 44-52. Kazuya, Sasaki, Kazuhiro, Miyashita, Masayoshi, Edamura, Takao, Furukawa and Yoshio, Shimizu (1997), “Evaluation of foundation comfort based on sensory evaluation and dynamic clothing pressure measurement”, Jpn. Res. Assn. Text. End-Uses, 38, pp. 53-8. Noriko, Ito, Mari, Inoue, Masae, Nakanishi and Masako, Niwa (1995), “The relation among the biaxial extension properties of girdle cloths and wearing comfort and clothing pressure of girdles”, Jpn. Res. Assn. Text. End-Uses, 36, pp. 102-8.
Garment’s pressure sensation 327
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Theoretical analysis of the geometry of the inclined stitch as a structural element of interlacings
Received January 2002 Accepted June 2002
A. Charalambus Technical University Sofia, Bulgaria Keywords Fibre, Yarns Abstract The geometry of interlacing with different stages and ways of greating are technically investigated. The theoretical lengthening of the fiber in the inclined stitches is defined by different conditions. Preconditions are searched, by which the values of this lengthening are within various limits and do not affect the quality of the used yarns and the ready knitting.
International Journal of Clothing Science and Technology, Vol. 14 No. 5, 2002, pp. 328-333. q MCB UP Limited, 0955-6222 DOI 10.1108/09556220210446130
The inclined stitch is a basic component structural element of knitting of meshes, interlacings, aran, cable, cord, racked and other knitting patterns (Figure 1). Usually, during the knitting process, it is made an upright face or a reverse stitch. Subsequently, in dependence on the desired knitting effect, it tilts through different knitting techniques. In the inclining process different forces act upon the thread, forming the stitch, which change its geometry. Usually stretching forces, which prolong it, act in the thread. During the actual inclining process these forces and prolongations are big and depend on the used technique and the desired knitting effect. Sometimes structural changes neighboring the inclined stitches knitting sections also occur, through geometrical change of the different stitch parts. After the end of the inclining process and the balance of the knitting (Charalambus and Hadzhidobrev, 2001a, b), the lengthening of the sticthes decreases by balancing the forces in the threads. We can assume approximately, that during the inclining process the stitch has the form as shown in Figure 1(a). If we assume, that the length of the thread in the right stitch is ‘H, the length of the inclined one during the inclining process is ‘0 and in a balanced state it is ‘y then ‘H , ‘y , :‘0 : If we also assume, that the thread is an ideal elastic body and after the balancing it turns back to its initial length completely, then in the very geometrical structure definite specific changes occur. In this case the model in Figure 1 will not correspond to the reality. In order to pass a normal knitting and inclining process of the stitch, it is necessary that the lengthening of the thread in the inclined stitch to the within the limits of its elastic prolongation (Charalambus and Hadzhidobrev, 2001a, b).
Analysis of the geometry of the inclined stitch 329 Figure 1. Parameters of inclined stitch during the knitting process (a) and in ready knitting fabric (b)
In many cases, especially for knitting of complex structures (cable stitches, aran) (Charalambus, 1995) this prolongation is outside the limits of its elastic values, by proceeding in the flow area. There is a risk from part or complete destruction of the cohesion of the threads and their tearing. This interrupts the knitting process and worsens quality of the product. That is why it is important to investigate the influence of the different conditions of knitting and inclining of the stitches over the physical-mechanical properties of the thread. The lengthening of the threads within the limits of the flow area (Charalambus and Hadzhidobrev, 2001a, b) causes changes in the thread structure, thus worsening their basic physical-mechanical indexes. This reflects negative over the knitting properties. In some measure this question can be solved with the use of high-elastic threads which have large limits of elastic prolongation. On the other side the products of these materials have low physical-mechanical indexes (stretching and fraying solidity). Besides, the knitting effect does not give very often the desired quality of the relief of the knitting. This problem also could be solved if the inclined stitches are being made in the very knitting process by reaching the exact necessary length of the thread, which will be other than this of the right stitch. In the modern technologies this is being solved with the use of more than two needle beds or through an individual compactability of every stitch in one stitch row. The task is to make such conditions, during the knitting and inclining process of the stitch, that the structure of the threads of traditionally used materials will not change. Thoroughly the physical-mechanical properties of the yarn during the inclining process of the stitch are influenced by the size of the lengthening of the thread in the inclined stitches, on the kind of the structure and the parameters of the knitting machine (Figure 1(a)). If we accept that the sections of the stitch head and sinker loop does not change during the inclining process, it follows that the lengthening of the thread will be expressed with the change
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of the L0, which will correspond to the legs of the inclined stitch. This length can be defined by the expression pffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi L0 ¼ h 2 þ t 2 ð1Þ where t is the needle step of the knitting machine and h is the loop length during the knocking-over. In case that cable pattern with different stages and ways of making are investigated, expression (1) is transformed into: pffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi L0 ¼ m 2 h 2 þ n 2 t 2 ð2Þ If we accept, that h ¼ kt; where k is a coefficient, corresponding to specific knitting conditions, then, according to equation (2): pffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi ð3Þ L0 ¼ t m 2 k 2 þ n 2 Then obviously the common actual lengthening of the stitch during the inclining process will be: pffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi D‘ ¼ 2ðL0 2 hÞ or D‘ ¼ 2t m 2k 2 þ n 2 2 k ð4Þ This common lengthening D‘ is also equal to the amount of the lengthening of the structural change of the knitting D‘str and the lengthening of the thread D‘th: D‘ ¼ D‘str þ D‘th
ð5Þ
In order to avoid changes in the cohesion of the threads it is necessary that the lengthening D‘th is within the limits of the elastic prolongation D‘el D‘th , D‘el
ð6Þ
It follows from equations (4), (5) and (6) that the following inequality must concern the limits of the elastic prolongation: pffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi D‘el . 2t m 2 k 2 þ n 2 2 k 2 D‘str The geometry of cable pattern in a balanced state with different stages and ways of creating is investigated from theoretical aspect. The theoretical lengthening of the thread in the inclined stitches by different conditions is being defined. For this purpose the index “angle of inclining” a is shown in, which thoroughly reflects the lengthening of the thread (Figure 1(b)). This angle depends on the height B and the width of the stitch A, on the number of
the crossed stitches in the cable pattern n and on the number of the stitch rows, where the crossing is made m (Charalambus, 1995; Dalidovich, 1970). From Figure 1(b) it follows that: pffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi L ¼ m 2B 2 þ n 2A 2 ð7Þ
Analysis of the geometry of the inclined stitch 331
and sin a ¼
mB L
According to equation (7) mB sin a ¼ pffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi m 2B 2 þ n 2A 2
ð8Þ
The coefficient of the correlation of the compactabilities Kp is equal to: Kp ¼
B A
ð9Þ
or B ¼ K pA When we replace equation (9) in equation (8) it follows that: mK p A sin a ¼ qffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi m 2 K 2p A 2 þ n 2 A 2 or mK p sin a ¼ qffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi m 2 K 2p þ n 2 Then mK p a ¼ arc sin qffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi m 2 K 2p þ n 2 By using the last expression the angle of inclining of different cable patterns is defined if K p ¼ 0:865 and for various values of m and n. In Table I the different values of L/A are shown, and also the angle a by the relevant values of m and n. The ratio L/A according to these arguments expresses the change of the lengthening of the inclining for different kinds of cable patterns.
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332 Table I.
n
m¼1
L/A m¼2
m¼3
m¼1
a m¼2
m¼3
0 1 2 3 4 5 6
0.865 1.322 2.179 3.122 4.092 5.074 6.062
1.73 1.998 2.644 3.463 4.358 5.291 6.244
2.595 2.781 3.276 3.966 4.768 5.633 6.537
90 41 23 16 12 10 8
90 60 41 30 23 19 16
90 70 53 41 33 27 23
Figure 2 shows clearly that the lengthening of the thread in the stitch expressed with L/A increases with the increase of m and n. When n increases the influence of the value of m becomes more insignificant. Figure 3 shows that when n increases, the angle of inclining decreases. It also increases with increase in m.
Figure 2.
Figure 3.
From these researches we can make the conclusion, that the lengthening and the tensions in the threads during the process of greating of knitting with inclined stitches have different values, which correspond to three stages.
Analysis of the geometry of the inclined stitch
(1) A stage of inclining process. (2) The end of the inclining process. The created inclined and right stitches are still in a kind of loop on the needles (Figure 1(a)). (3) Throwing away of the knitting from the knitting machine and its complete balance. The lengthening and the tensions have highest values in the first moment. Then the bigger risk of reaching the dragging out area and worsening of the physical-mechanical properties of the threads. It is necessary that the maximum value of the thread lengthening us within the limits of the elastic area. In this case the physical-mechanical properties of the thread does not worsen, the knitting and inclining process passes normally and knitting with high quality indexes is made. References Charalambus, A. (1995), “Analysis of the knitting process of knitting cable patterns”, magazine Textiles industry, Sofia, Bulgaria, 6S, pp 11-13. Charalambus, A. and Hadzhidobrev, P. (2001a), “Theoretical aspects of the mechanics of the structure of relief knitting”, magazine Textiles- Clothing Sofia, Bulgaria, 2S, pp 5-8. Charalambus, A. and Hadzhidobrev, P. (2001b), “Defining of the stretching of the threads in the float stitch with reading only the elastic lengthening”, Textiles- Clothing, Sofia, Bulgaria, 3S, pp 7-9. Dalidovich, A.S. (1970), Principles of the theory of knitting, Moscow.
333
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Optimal marking of garment patterns using rectilinear polygon approximation In Hwan Sul and Tae Jin Kang
Received December 2001 Revised April 2002 Accepted April 2002
School of Materials Science and Engineering, Seoul National University, Seoul, Korea Keywords Garments, Garment design, Manufacturing Abstract Pattern marking is the allocation of garment patterns on the cloth roll minimizing the fabric loss, and thus very important for the cost reduction in garment manufacturing industries. But automatic marking is very difficult because it is a non-deterministic in polynomial time problem. Most previous pattern marking methods needed collision detection routine to lay out patterns without interfering each other, which was the bottle neck of nesting speed. In this study, rectilinear polygon approximation technique was used to reduce the overall calculation time because the garment patterns are usually in non-convex shape that can effectively be approximated by rectangles. Additionally, we adapted stochastic simulated annealing to search the optimal pattern marking.
International Journal of Clothing Science and Technology, Vol. 14 No. 5, 2002, pp. 334-346. q MCB UP Limited, 0955-6222 DOI 10.1108/09556220210446149
1. Introduction Fabric is the major raw material which comprises the most part of production cost in garment manufacturing industry. Therefore the minimization of fabric consumption is needed to reduce the production cost, which is fulfilled by improving marking efficiency. Nowadays three different methods of marking are mostly in use. One is manual marking by a skilled marking expert. A second is computerized automatic marking. The latter is more economical but yields lower efficiency in utilization of the fabric than the former. The third method is the interactive method as a trade-off, which still needs human labor. The fabric pattern marking is a combinatorial optimization problem which is allocating non-convex polygons of various shapes in a two dimensional space. Because this is a case of NP-hard (non-deterministic in polynomial time) problem, it is infeasible to find the “best” solution. But it is better to seek to find as optimal a solution as possible. That is, we are able to search the solution with the highest efficiency among a large number of possible markers. Therefore the fabric pattern marking problem can be thought in two aspects, which are individual marker making algorithm and optimal marker searching. There have been many researches on effective marking algorithm not only in the garment industry, but also in VLSI chip designing and shipbuilding
industry. Adamowicz and Albano (1976) used No-Fit-Polygon (NFP) algorithm Optimal marking to nest polygons of complex shape. Nee and Cheok (1991) devised an algorithm of garment for ship structural plates. Jang and Han (1999) used column nesting technique patterns for nesting and cutting path generation. In fabric pattern marking, the fabric patterns are overlapped outside the sewing line. This characteristic increases the degree of freedom of allocating 335 patterns that there is an additional burden on calculation, but we can make a marker of higher efficiency only by reducing the overlapping patterns. We used 2-step marking algorithm to overcome this difficulty while enhancing the marking speed. The patterns are allocated at random positions after rectilinear approximation. And the positions of patterns are slightly adjusted to produce higher efficiency allowing pattern overlapping. It is necessary to select the most efficient marker as the earlier marking method generates different marker each time with random values. We adopted simulated annealing to avoid being stuck in local optimum during the searching procedure. Besides, there are an unlimited number of markers depending on the pattern shape and pattern order to allocate. Ismail and Hon (1992) and Jacobs-Blecha Riall (1991) and proposed Artificial Intelligence based method such as genetic algorithm to find the optimal solution among the numerous ones. Genetic algorithm is based on probabilistic method, so there is no guarantee to find the optimal solution even under unlimited time condition. So we adopted the simulated annealing which is proved to reach the best solution in unlimited trial mathematically (Rutenbar, 1989).
2. Marking algorithm 2.1. Rectilinear approximation of patterns Previous marking algorithms (Jacobs-Blecha and Riall, 1991) fixed the order in which the patterns are allocated and the patterns were located at the BottomLeft-Most position (Downsland and Downsland, 1993; Art, 1966). Fabric patterns are of various shape and size, it is not recommended to fix the order with only several simple rules such as size or aspect ratio (Art, 1966). But it is probabilistically more feasible to allocate the patterns by random order. In this case, much of the calculation time is spent in collision detection between patterns to be allocated and patterns already allocated to avoid the overlapping of patterns. This is due to the fabric patterns’ complex shape of non-convex polygon. Analytical method such as Minkowski difference for this kind of collision detection problem exists. But such analytical methods need long calculation time thus impractical to use in pattern marking problem where collision detection between patterns are repeated many times. To reduce the collision detection time among patterns, we approximated each pattern as a
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rectilinear polygon which is a combination of small element rectangles. We do not place the pattern itself but place each rectilinear polygon of pattern on the die. And then each rectilinear polygon is replaced with original pattern polygon. Because each rectilinear polygon is mere an approximation, the die filled with pattern polygons which are replaced with rectilinear polygons may have void spaces between them. The VLSI chip design or shipbuilding problems has the condition that each polygon should adjoin one another. Rectilinear polygon has approximation error, so it may be inappropriate to such areas. But in fabric pattern marking, each pattern may overlap slightly with nearby ones outside the sewing line because the real surface that constitutes clothes is the part inside the sewing line. Jacobs-Blecha and Riall (1991) enhanced the efficiency of human-made pattern marker by adjusting the pattern positions slightly allowing overlapping of patterns in a predefined limit. The reason we approximated each polygon is pattern positions are changed many times in heuristic searching. When placing each pattern, it is time-consuming to check the collision whether patterns are adjoining, much more to allow pattern overlapping. Moreover, even if several pattern pieces are allocated allowing overlapping, it cannot guarantee that the whole marker will be also efficiently marked. So we achieved pattern marking with two steps, pre-marking and main marking. In the pre-marking, we approximated each pattern with rectilinear polygon and then placed the rectilinear polygons adjoining one another, thus not allowing overlapping. In the main marking, each pattern moves slightly from original positions many times allowing overlapping nearby patterns, so that void space between patterns is removed and overall marker efficiency is improved than the pre-marking result. The amount patterns overlap can be decided by the user.
2.2. Rectilinear approximation scheme Figure 1 shows the rectilinear approximation scheme. The original pattern polygon is masked with grids of small rectangle cells, and the cells containing the original polygon are marked as effective cells. So the overall effective cells forms rectilinear polygon. And we found the smallest number of rectangles which can compose the rectilinear polygon. We defined the number of rectangles as “multiplicity”. As the size of rectangle cell is decreased, the rectilinear polygon approximates the original polygon more accurately with increasing calculation time. So we found that the multiplicity of 5-6 was appropriate. There are a number of researches about allocating rectangles. Among them, we used Sakanushi et al. (1998) Multi-BSG algorithm which is applicable both for rectangles and rectilinear polygons.
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Figure 1. Rectilinear polygon approximation of patterns
2.3. Multi-BSG algorithm Figure 2 shows the example of allocation of simple rectilinear polygons using Multi-BSG algorithm. Multi-BSG is an extended methodology of single BSG. The brief principle of the algorithms is as follows. 2.3.1. Single-BSG. Single BSG algorithm does not determine the exact position of the rectilinear polygons, but determines only their relative positions
Figure 2. Example of rectilinear polygon nesting using Multi-BSG
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Figure 3. Rectangle nesting using Multi-BSG method
in the allocation table (Figure 3(b)). Each room of the allocation table can hold only one polygon, and the room where each pattern will be laid is decided by random values of x- and y- directions.
In Figure 3(b), the lines of the table are composed of broken segments of lines. Optimal marking The shape of the line segments determines whether the rectangles beside the of garment line segment are placed side by side or not. In the row direction, two patterns rectangles with a line between them are laid in succession in x direction. For example, rectangles A and B, B and C, B and D of Figure 3(b) are meeting with a common line between them, so they are laid in queues in the x direction 339 (Figure 3(c)). In the column direction, rectangles C and D, D and E of Figure 3(b) are meeting with a common line between them, so they are laid in queues in the y direction. Now the relative position of rectangles A, B, C, D, E is determined. The absolute positions of the rectangles are determined by the assumption that the rectangles are adjoined in x- or y- direction with each other. For example, x coordinate of the left-hand most rectangle (rectangle A) is set to 0.
x coordinate of rectangle A ¼ 0
As the rectangle B is adjoined with rectangle A in the x- direction,
x coordinate of rectangle B ¼ x coordinate of rectangle A þ width of rectangle A
Also x coordinate of rectangle C can be calculated by
x coordinate of rectangle C ¼ x coordinate of rectangle B þ width of rectangle B ¼ x coordinate of rectangle A þ width of rectangle A þ width of rectangle B
Now rectangle D also meets rectangle B in the x direction, so
ð1Þ
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¼ x coordinate of rectangle A þ width of rectangle A þ width of rectangle B ¼ x coordinate of rectangle C X coordinate of rectangle E can be set to 0. The y coordinates are calculated in the same way. Y coordinate of the lower most rectangle (rectangle E) is set to 0. So the final allocation result is y coordinate of rectangle E ¼ 0 y coordinate of rectangle D ¼ y coordinate of rectangle E þ height of rectangle E y coordinate of rectangle C ¼ y coordinate of rectangle D þ height of rectangle D ¼ y coordinate of rectangle E þ height of rectangle E þ height of rectangle D
ð2Þ
Y coordinates of rectangle A and B are the same of rectangle D. So the final allocation of the five rectangles are as Figure 3(c). 2.3.2. Multi-BSG. Multi-BSG is used to find allocation of rectilinear polygons. As the rectilinear polygon is composed of several rectangles, we need tables as many as multiplicity of rectilinear polygons (Figure 3(d)), while we need one allocation table for simple rectangles. If a rectilinear polygon is composed of n rectangles, n tables are needed. And the shapes of line segments of each table are all slightly different so as to compare the positions of element rectangles of rectilinear polygons. For one rectilinear polygon, the element rectangles have the same room positions of each table. As the size of rows and columns of allocation table increase, the possibility for finding better optimal result increases, while the calculation time increase.
We found the table size of n £ n was appropriate for the number of rectangles Optimal marking being n. of garment All the patterns were considered to be polygons to reduce the amount of patterns calculation. Allocating patterns with its original polygonal shapes need calculation of order Oðn 2 £ m 2 Þ
ð3Þ
where m is the maximum number of polygon edges. In allocating rectangles using an allocation table, each rectangle lies in queues in x or y direction. So the x coordinate of any reference rectangle is known by the width values of the patterns which lie left side of the reference pattern. Y coordinates are also known by the height values of the rectangles. From equations (1) and (2), positions of a rectangle is known by several times of addition operation. That is, when n rectangles are in an allocation table of size p £ q; we need, not more than 2 £ p £ q times of addition to get the x or y coordinates. As the table size p £ q has the only condition that p£q$n
ð4Þ
minimizing the table size makes the order of calculation OðM £ nÞ
ð5Þ
This means the overall calculation will be decreased relatively to equation (3). In the practical pattern making processes the patterns for one or two suits of clothes are marked, which are about 100-200 patterns. Therefore, allocation using rectilinear polygon approximation is more economical than using the original polygons. Since the pattern marking is a case of NP-hard problems, the possible number of marking increases drastically with increasing number of patterns. As the marking result is made by the random values, we should try as many trials as possible to get the more efficient marker. But we cannot estimate how many times of marking trials will get a certain level of efficiency which most of user want. In the actual garment manufacturing process, we are not allowed unlimited time for pattern marking in search of better efficiency. So it is necessary to reduce the calculation time of each marking trial. 2.4. Optimal marker searching using simulated annealing To find the better efficiency of marking, we need to iterate the marking trial with changing the positions of rectilinear polygons slightly. There are a large number of choices where we allocate the polygons. The order of number of possible markers is O(n!), so it is necessary to select the best one among those. The simulated annealing is the appropriate searching method. Since it is a
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Figure 4. Flow chart of simulated annealing
heuristic searching method, it is possible to find the marker of maximum efficiency in theory if we are given unlimited time of trial. Other searching algorithm such as Monte Carlo method does not guarantee to find the marker of maximum efficiency because it is a stochastic search. Figure 4 shows the simulated annealing algorithm embedded in the marking procedure. The position of the patterns in the marker is slightly modified in every trial. When the modification brings the better efficiency, the new marker is selected as result just as in hill climbing method (Sakanushi et al., 1998). The differences between simulated annealing and hill climbing lies when the modification brings the poorer efficiency. Hill climbing method has the shortcomings that it can be stuck in the local optimum nearby the starting solution. This is due to the hill climbing method is deficient in ability to skip
such local optimum of poor efficiency. To overcome this problem, the simulated Optimal marking annealing adapted random value e and parameter P which is a function of of garment temperature both ranging from 0 to 1. patterns The simulated annealing comes from the annealing process of metals. The temperature T is an analogue of number of marking trials in the marking procedure, while the dE is an analogue of difference of marker 343 efficiency before and after modification. To skip the local optima of poor efficiency in the early stage, parameter P is low value near 0. As e is a random value, e tends to be greater than P. When the modification to the marker brings the better efficiency, the modification is accepted. Even if the result is poorer, the modification can be accepted only if e is greater than P. So at the early stage of modification, it is more common to accept the poorer modification result. This is desirable because the marking efficiency of early stage is generally poor because the patterns are allocated randomly. Repeating such modifications and accepting even poorer result, the marker efficiency grows slightly with number of trial as shown in Figure 5. As seen in the Figure 5, it shows that the algorithm is skipping the local optima successfully. As approaching the global optimum, the temperature is decreased and the parameter P has the value near to one. And the poorer modification is apt to be deserted. This is because skipping local optima with low P value can lead to divergence.
Figure 5. Efficiency vs. number of marking trials
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2.5. Final marking with collision detection Marking with rectilinear polygon approximation can lead to some void or overlapping between patterns due to the approximation error. To remove the void and to allow limited overlapping of patterns, final marking is done with collision detection of pattern polygons. The ratio at which the patterns are overlapped is determined by the user. The position of the pattern is adjusted little by little so that the patterns are overlapped inside the user-defined overlapping ratio. But the patterns are not overlapped inside the sewing line.
3. Results and discussion We programmed an application for pattern marking, using rectilinear polygon and marking, using shape function (Figure 6). The platform was IBM-PC with Pentium II-300 MHz C.P.U. and the compiler was Borland C++ Builder 4.0. The codes are written in C++ language and the patterns were considered as polygons. The marking efficiency and overlapping ratio are defined as PNumber Marking efficiency ¼
Figure 6. Program window
of patterns
Area of ith pattern £ 100ð%Þ Area of enclosing rectangle
i¼1
Overlapping ratio ¼
Optimal marking of garment patterns
Overlapped area Area of original pattern
3.1. Pattern marking using rectilinear polygon Comparing the rectilinear polygon approximation with marking with original polygons, we generated each 100 polygons of various number of edges and compared the calculation time to reach 80 per cent efficiency (Table I). The multiplicity of rectilinear polygons was fixed to six. In the case of triangles (degree 3) or rectangles (degree 4), marking with original polygons was faster. But the fabric patterns are generally of complex shape, and the rectilinear approximation is appropriate as shown in the table. As the degree of polygon increases, the time taken for the collision detection between polygons increases in proportion to the square of number of patterns. That is why the marking with original shape takes more calculation time as the pattern shape becomes more complex. In the case of rectilinear approximation, the calculation time also increases, but not so much as the previous method. This is because the rectilinear polygon is a combination of finite number of rectangles. The calculation time for each marking decreases, it is possible to find the better efficiency of marker under condition of the same marking time given. The calculation time for the degree 30 and 15 is similar due to error resulting from rectilinear approximation. This error is corrected by the main marking step using collision detection.
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3.2. Optimal marking searching using simulated annealing Figure 5 shows the number of marking trial versus marking efficiency. The initial marker shows very low efficiency because the patterns are allocated
Degree of polygon 3 4 5 6 7 8 9 10 15 20 25 30
Number of polygons 100 100 100 100 100 100 100 100 100 100 100 100
Marking time (s) Collision detection Rectilinear approximation 8.4 12.0 15.2 17.6 20.1 25.0 39.2 50.2 75.9 91.0 108.2 199.8
23.5 24.6 25.2 25.7 28.0 29.2 29.9 30.1 32.2 31.8 32.0 32.5
Table I. Comparison of marking results
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randomly without any allocation rules. As the modification repeats, the efficiency increases monotonously. And the searching procedure is not stuck to local optima. But as the efficiency approaches the global optimum, skipping of local optimum is rare, thus minimizing the possibility of diverging. 4. Conclusion We allocated fabric patterns starting from random positions without any rule and searched the most efficient marker among the modified marking results using simulated annealing method. The patterns were not laid with their original polygonal shape, but they were approximated as rectilinear polygon to reduce the calculation time. As the pattern shape becomes complex, the rectilinear approximation method proved to be faster than the previous method. Generally the fabric patterns are of complex shape so the rectilinear approximation has the advantage to find the more efficient marking result. References Adamowicz, M. and Albano, A. (1976), “Nesting two dimensional shapes in rectangular modules”, Computer Aided Design, 9 No. 1, pp. 48-52. Art, R.C. (1966), “An approach to the two-dimensional irregular cutting stock problem”, IBM Cambridge Scientific Center Report, 36-Y08. Downsland, K.A. and Downsland, W.B. (1993), “Heuristic approach to irregular cutting problems”, Working Paper EBMS/1993/13, European Business Management School UC Swansea, UK. Ismail, H.S. and Hon, K.K.B. (1992), “New approaches for the nesting of two-dimensional shapes for press tool design”, International Journal of Production Research, 30 No. 4, pp. 825-37. Jacobs-Blecha, C. and Riall, W. (1991), “The feasibility of improving the marker making process”, International Journal of Clothing Science and Technology, 3 No. 4, pp. 13-24. Jang, C.D. and Han, Y.K. (1999), “An approach to the optimal allocation of irregular shapes and cutting path optimization”, Journal of Ship Production, 15 No. 3, pp. 129-35. Nee, A.Y.C. and Choek, B.T. (1991), “Algorithms for nesting of ship/offshore structural plates”, ASME Advances in Design Automation, 2, pp. 221-6. Rutenbar, R.A. (1989), “Simulated annealing algorithms: an overview”, IEEE Circuits Device Magazine, pp. 19-26. Sakanushi, K., Nakatake, S. and Kajitani, Y. (1998), “The Multi-BSG: stochastic approach to an optimum packing of convex-rectilinear blocks”, Proceedings of ACM/IEEE International Conference on Computer Aided Design’ 98, pp. 267-74.
International Journal of Clothing Science and Technology
ISSN 0955-6222 Volume 14 Number 6 2002
International textile and clothing research register Editor-in-Chief George K. Stylios Paper format International Journal of Clothing Science and Technology includes six issues in traditional paper format. The contents of this issue are detailed below.
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Editorial The International Textile and Clothing Research Register Championing the Research Efforts of the Community The International Textile and Clothing Research Register (ITCRR) is in its eighth year of publishing the research efforts of our community. It provides a breadth of activity in the field of textile and clothing research and it encourages participation and dissemination to those working in this discipline and further afield. Research, development and innovation can, without doubt, give us more wisdom, enable our industries to become more competitive, and contribute to our quality of life. I believe that registering research projects will provide the due credit to originators of the research and contribute much more to the future development of this field. Groups of expertise can be identified in this manner, repetition and re-invention can be avoided, leading to best utilisation of time and funding for faster and better directed research in the international arena, since globalisation is on everybody’s agenda. The ITCRR has been set up with all these things in mind. Textiles and clothing originate from the physiological need to protect ourselves from the environment. This has made necessary the art of hand knitting and weaving, and cut and sew processes, which have been evolving for many centuries. Although the original need for clothing has somewhat changed, mechanisation of this process started after the industrial revolution and has continued this century, with automation developments on a massive scale. Considering the upstream part of the whole textile and clothing production chain, yarn-making is the most highly automated area, followed by fabric, with high speed knitting and weaving machines. The downstream part of garment making, however, still remains probably the less developed connection in this chain; one that no doubt many of us have our eyes on as the candidate for development into the new century. With massive computerisation over the last 20 years, logistics and sales have also changed dramatically from pen and paper to electronic data interchange and electronic point of sale. Consistent and extensive research and development in textile and clothing science and technology underpin all these developments by the international research community, whether in educational establishments, in research trade organisations, or in companies. IJCST has been set up as a platform for the promotion of scientific and technical research at an international level. With the statement that the manufacture of clothing in particular needs to change to more technologically advanced forms of manufacturing and retailing, IJCST will continue to support the community in these and other efforts. The journal will continue with its authoritative style to accredit original technical research. The refereeing process will continue but we will be
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implementing a pilot scheme, which will be designed to reduce waiting time during the refereeing process. IJCST will be instrumental in supporting conferences and meetings from around the world in its effort to promote the science and technology of clothing. I praise the enthusiasm of our research community and those authors who have made IJCST an invaluable resource to all involved with textiles and clothing. I thank our editorial board for their continuous support and our colleagues who have acted in a refereeing capacity, with commitment to progress our research efforts. I take the liberty to list some of those names below (apologies in advance if anyone has accidentally been omitted from this list): Dr. Norman Powell, University of Bradford Dr. Taoruan Wan, University of Bradford Professor David Lloyd, University of Bradford Dr. Jim Betts, University of Bradford Dr. Steve Heycock, University of Bradford Dr. Lu Cheng, University of Bradford Dr. Simon Harlock, University of Leeds Dr. G.A.V. Leaf, University of Leeds Dr. David Brook, University of Leeds Dr. C Iype, University of Leeds Dr. Jaffer Amirbayat, UMIST Dr. David Tyler, Manchester Metropolitan University Dr. Jintu Fan, Hong Kong Polytechnic University Dr. Lubas Hes, University of Minho Dr. Jelka Gersak, University of Maribor Professor Paul Taylor, University of Hull Professor Haruki Imaoka, Nara Women’s University Professor Mario De Araujo, University of Minho Professor H.J. Barndt, Philadelphia College of Textiles and Science Professor Masako Niwa, Nara Women’s University Professor Jachym Novak, Vysoka Skola Sronjni a Tectilffi Professor Isaac Porat, UMIST Professor Roy R Leitch, Heriot-Watt University Professor Ron Postle, The University of New South Wales Professor Gordon Wray, Loughborough University of Technology Professor Witold Zurek, Lodz Technical University Thank you all subscribers, authors, editorial board members, referees, publishing team, colleagues and students for your support and note that my address for correspondence is: Heriot-Watt University, School of Textiles, Netherdale, Galashiels, Selkirkshire, TD1 3HF, Scotland, E-mail:
[email protected] George K. Stylios Editor in chief
Research register Belfast, UK Queens’ University, Belfast, Ashby Building, Stranmillis Road, Belfast BT9 5AH Tel: 0289 0 274147; Fax: 0289 0 661729 School of Mechanical & Manufacturing Engineering Dr J. McCartney, Dr B.K. Hinds Research staff: Dr B. Seow
Three dimensional design using fabric properties Other partners: Academic Industrial None Sara Lee Courtaulds Project started: 1 August 1999 Project ended: 31 July 2001 Finance/support: £135,008 Source of support: Sara Lee Courtaulds, IRTU Keywords: Performance fabrics, Fabric characteristics, Fabric modeling In common practice, the patterns for a newly designed garment are created by an experienced pattern technologist, made into a garment and worn by a standard model. This garment may be required to go through various alteration cycles until the fitting is deemed good. A range of sizes are then derived from these sample patterns. The entire process from concept garment to an approved set of patterns can take up to 12 weeks. This project aims to both improve and shorten the design process. A formula to predict the 3D behavior of textile materials will be developed. The formula will then be incorporated in a computer-engineering model that predicts the 3D deformation of material under load conditions. A prototype garment CAD system developed at the end of this project will allow the user to design a garment on a 3D underlying body, automatically producing as its output the 2D shape of pattern of fabric necessary to give the 3D stress shape. This would both improve and shorten the design process. Details of research include devising mechanical testing equipment to determine new material characteristics that takes into account grain direction sensitivity. The test result is then used to validate the simulation model. This simulation model will then be tested on hybrid constructions such as seams and straps.
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Project aims and objectives The objectives of the project are to characterise the behavior of textile materials and to use this data in a computer-engineering model, which predicts the 3D deformation under load conditions. This will lead to the definition of 2D patterns necessary to give the 3D stressed shape. A prototype garment CAD system will be developed by the end of this project. Research deliverables (academic and industrial) . Bi-directional energy model for knitted fabrics. . Test device for model validation. . Prototype CAD system. Publications Not available
Bolton, UK Bolton Institute, Deane Road, Bolton, BL3 5AB, UK Tel: 01204 903108; Fax: 01204 399074; E-mail:
[email protected] Leah Higgins, Advanced Materials Research Center Research staff: Prof. S. C. Anand (Director of Studies), Dr. D. A. Holmes (Supervisor), Dr. M. E. Hall (Supervisor)
Effect of laundering on dimensional stability, distortion and other properties of cotton fabrics (Ph.D. Project) Other partners: Academic Industrial None Whirlpool Corporation, USA Project started: March 2000 Project ends: February 2003 Finance/support: $16,000 per annum Source of support: Whirlpool corporation Keywords: Cotton, Laundering, Dimensional stability, Wrinkling New cotton garments tend to shrink and distort when first laundered, particularly if they are tumble dried. Although this behaviour is often an
inevitable consequence of the manufacturing and finishing process consumers tend to blame their laundering equipment. This project is the second Ph.D. project in an ongoing collaboration between Bolton Institute and Whirlpool Corporation. The underlying aim of this research is to gain a better understanding of how different laundering factors effect the levels of shrinkage, distortion and also wrinkling observed in new cotton fabrics on initial laundering. This knowledge will allow the project sponsors to develop laundering equipment that is less damaging to the appearance and dimensional stability of cotton fabrics. Publications Higgins, Anand, S. C., Hall, M. E. and Holmes, D. A. (2002a), ‘‘Factors during tumble drying that influence dimensional stability and distortion of cotton knitted fabrics’’, International Journal of Clothing Science and Technology (in Preparation). Higgins, L., Anand, S. C., Hall, M.E., Holmes, D.A. and Brown, K. (2001), ‘‘Effect of repeated laundering of dimensional stability and distoration of weft knitted cotton fabrics’’, IAT Conference Proceedings March 2001. Higgins, L., Anand, S.C., Holmes, D.A., Hall, M. E. and Underly, K. (2002b), ‘‘Rinse cycle softener and drying method and the effect of tumble sheet softener and tumble drying time’’, Textile Research Journal (in Preparation).
Bradford, UK University of Bradford, Bradford, UK Tel: +44 (0) 1274 384248; Fax: +44 (0) 1274 391333 Mr. J. Watson Department of Industrial Technology, Textile and Garment
Centre for objective measurement and innovation technologies (COMIT) for the textile clothing and retailing industries Other partners: Academic None Project started: 1 January 1993 Finance/support: £2.8 million
Industrial CBWT Bradford Council Project extended: December 2002
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Source of support: ERDF Keywords: Clothing, Garments, Retailing, Textiles The objective of the centre is to provide measurement, testing and interpretation services to the textile, clothing and retailing industries, using the technologies resulting from many years of innovative research work, carried out at the University of Bradford. The unique systems employed measure fabric parameters objectively. These measurements are analyzed and interpreted to determine optimum manufacturing parameters to produce quality products for a competitive market. The project has recognised the importance of objectively quantifying products and processes, and their interpretation in a traditionally skills-oriented industry, where subjectivity hinders its future development. Technological innovations in which the group at COMIT has contributed in recent years have provided instrumentation measurement systems and procedures which can enable the industry to increase quality, added value, production efficiency, waste minimization and sustainability, to compete globally and penetrate newly emerging markets. To that effect COMIT is preparing our local industry to make best use of the technology, and it also feeds back industrial requirements to the EU committee. Project aims and objectives The promotion, standardization and implementation and training for the textile, clothing and retailing industries, through objective measurement technologies, to improve competitiveness of the industry in the world market. To develop further and extend the services of COMIT to a large client base of SMEs within the textile clothing and retailing industries. Research deliverables (academic and industrial) COMIT has been extended into 2002; with this phase the scheme will incorporate new research in yarns and garments, which will enable the scheme to become coherent and more comprehensive. Through this initiative the centre has developed close working relationships with over 300 companies, providing training in objective measurement technologies, measurement and interpretation, development of fabric fingerprinting, prediction of optimum sewing conditions and fabric/garment aesthetics. Other activities of the centre include successful identification of a number of individual industrial projects which are currently under way and several successful industrial graduate placements have already taken place.
Budapest, Hungary Budapest University of Technology and Economics (BUTE), Budapest, M} uegyetem rkp. 3., H-1111 Hungary Budapest, H-1521, Hungary Tel: +36-1-463-1376; Fax: +36-1-463-1376; E-mail:
[email protected] Prof. Judit Borsa Department of Plastics and Rubber Technology
Effect of quaternary ammonium compounds on structure and reactivity of cellulose Other partners: Academic Industrial Department of Analytical Chemistry, None BUTE Department of Physical Chemistry, BUTE Department of Chemical Technology, BUTE Chem. Research Center of the Hungarian Academy of Sciences Johannes Kepler University, Linz, Austria Dr. Habil Ildiko Tanczos Project started: 1 January 1999 Project ends: 31 December 2002 1 January 2002 31 December 2003 Finance/support: Euro 15,000, Euro 5,000 Source of support: Hungarian National Research Fund and Austrian-Hungarian Scientific Exchange Program Keywords: Cellulose, Cotton, Tetraalkylammonium compounds, Tetramethylammonium hydroxide, Sodium hydroxide, Swelling, Mercerization Quaternary ammonium compounds are intracrystalline swelling agents of cellulose, moreover, they are also its good solvents in the case of sufficiently large size of molecule. Scientific literature on the effect of tetraalkylammonium hydroxides on cellulose is very limited, partly due to the relatively high price of these chemicals. Tetramethylammonium hydroxide has recently been applied in the electronic industry for surface cleaning, hence its price has significantly decreased. Some more information about the interaction of cellulose with these swelling agents, compared to sodium
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hydroxide, could be interesting both from a scientific and technological point of view.
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Project aims and objectives The aim of the work is to study the interaction of tetramethylammonium hydroxide (TMAH), the smallest member of the tetraalkylammonium hydroxide family, with cotton cellulose. Crystallinity, sorption capacity, water retention, dye uptake, effect of high energy irradiation etc. were investigated. Purification of various cellulose sources (wood, hemp, cotton) was also studied. Research deliverables (academic and industrial) It was found that TMAH is a more effective swelling agent of cellulose than sodium hydroxide. It was explained by its large size, partly apolar character, and extremely high activity. This property of TMAH might be used in various areas including textile industry. Publications Borsa, J., Ta´nczos, I., Sajo´, I., Juha´sz, Z.A. and To´th, T. M. (1999), ‘‘Activation of cellulose with tetramethylammonium hydroxide’’, Advances in Wood Chemistry, International Symposium (Proceedings), Wien, Austria. Taka´cs, E., Wojna´rovits, L., Fo¨ldva´ry, Cs., Borsa, J. and Sajo´, I. (2001), ‘‘Radiation activation of cotton cellulose prior to alkali treatment’’, Res. Chem. Intermediates, Vol. 27, pp. 837-45. Ta´nczos, I., Putz, R. and Borsa, J. (1999), ‘‘Comparative study on the effects and mechanism of the new quatam pulping’’, 10th International Symposium on Wood and Pulping Chemistry, Main Symposium (Proceedings), Yokohama, Japan, Vol. II, pp. 288-91. Ta´nczos, I., Borsa, J., Sajo´, I., La´szlo´, K. and Juha´sz, Z.A. (1998), ‘‘Comparison of the effect of sodium hydroxide and tetramethylammonium hydroxide on cotton cellulose’’, International Symposium in Wakayama on Dyeing and Finishing of Textiles (Proceedings), Wakayama, Japan, pp. 276-7. Tanczos, I., Borsa, J., Sajo, I., Laszlo, K., Juhasz, Z.A. and Toth, T.M. (2000), ‘‘Effect of tetramethylammonium hydroxide on cotton cellulose in comparison with sodium hydroxide’’, Macromolecular Chemistry and Physics, Vol. 201 No. 17, pp. 2550-6. To´th, I., Borsa, J., Reicher, J., Sallay, P., Sajo´, I. and Tanczos, I., ‘‘Mercerization of cotton with tetramethylammonium hydroxide’’, Textile Research Journal (in preparation).
Budapest, Hungary Budapest University of Technology and Economics (BUTE), Budapest, Mu¨egyetem rkp. 3., H-1111, Hungary, Budapest, H-1521, Hungary Tel: +36-1-463-1376; Fax: +36-1-463-1376; E-mail:
[email protected] Prof. Judit Borsa, Department of Plastics and Rubber Technology
Advanced textiles Other partners: Academic Industrial Chem. Research Center of the None Hungarian Academy of Sciences Bay Zolta´n Institute for Materials Science and Technology Ilona Ra´cz Ph.D. Cornell University, Ithaca, New York, USA Prof. S. Kay Obendorf, Johan Be´la National Center of Epidemiology Project started: 1 January 2001, Project ends: 31 December 2004, 1 July 2001 31 July 2004 Finance/support: Euro 25,000, Euro 30,000 Source of support: Hungarian National Research Fund, Hungarian National Research and Development Fund Keywords: Cellulose, Cotton, Chemical modification, Carboxymethylation, Pesticide protective clothes, Soil release, Medical textile, Antimicrobial textile Supermolecular structure and morphology of cellulose can significantly be modified by chemical modification. Slight carboxymethylation of cotton cellulose improves the accessibility of the fiber, which can be used for various purposes. Project aims and objectives The aim of the work is to find useful applications for a fiber with very high accessibility (sorption capacity). Slight carboxymethylation as durable finishing for various aims (pesticide protection, lipid soil release, antimicrobial properties) has been studied. Research deliverables (academic and industrial) Highly accessible cotton fiber was used for pesticide protective clothes. Durable carboxymethylation finish has been used on cotton fabrics to trap the pesticide on the fabric decreasing the transfer to the skin and also enhancing the removal of the pesticide by laundering. This finish improved also the lipid soil removal from cotton fabric. Studies on antimicrobial fabric are going on. Publications Borsa, J., Ra´cz, I., Obendorf, S.K. and Bodor, G. (1999), ‘‘Slight carboxymethylation of cellulose’’, Lenzinger Berichte, Special Symposium Issue, pp. 19-25. Borsa, J., Racz, I., Obendorf, S.K. and Bodor, G. (1999), ‘‘Slight carboxymethylation of cellulose’’, Advances in Wood Chemistry, International Symposium, Wien, Austria.
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Csisza´r, E., Borsa, J., Ra´cz, I. and Obendorf, S.K. (1998), ‘‘The reduction in human exposure to pesticide through selection of clothing parameters: fabric weight, chemical finishing, and fabric layering’’, Archives of Environmental Contamination and Toxicology, Vol. 35, pp. 129-34. Obendorf, S.K. and Borsa, J. (1999), ‘‘Carboxymethylierung von Baumwollflaeche zur Verbesserung der Trageeigenschaften’’, International Textile Bulletin, Vol. 45, pp. 40-2. Obendorf, S.K., Borsa, J. (2001), ‘‘Soil removal from chemically modified cotton’’, Detergent and Surfactant, Vol. 4 No. 3, pp. 247-56. Ra´cz, I., Obendorf, S.K. and Borsa, J. (1998), ‘‘Carboxymethylated cotton fabric for pesticide protective work clothes’’, Textile Research Journal, Vol. 68, pp. 69-74.
Dresden, Germany Technische Universita¨t Dresden, 01062 Dresden, Germany Tel: +49 351 4658 358; Fax: +49 351 4658 361; E-mail:
[email protected];
[email protected] Institute of Textile and Clothing Technology, Chair of Clothing Technology Prof. Dr-Ing. Habil Ro¨del, Ms. Dipl.-Ing. Elke Haase and Mr. Dr. sc. nat. Rolf Bochmann
Fundamental investigations for construction of compressive clothing and its effect on blood circulation Other partners: Academic Technische Universita¨t Dresden
Industrial None Faculty of Medicine Prof. Dr. med. A. Deussen Project ended: November 2001
Project started: September 1999 Finance/support: DM100,000 Source of support: German Research Foundation Keywords: Knitwear, Medical textiles, Physiology
The product quality of cloths depends not only on the physiological comfort. Also the mechanical impact could be of interest. One aim of the research project is the determination of the pressure and comfort requirements to induce the shape effect on the body. Another aim could be the improvement of the blood circulation. The blood circulation has a great influence of the capacity, productivity and health of the customer. Not enough work was done on the performance deterioration of the pressure garments in terms of blood circulation. This project initiates an integrative approach to analyze the relationships between the material parameters, the pattern construction and the biological
impact. Until now there have been no functional methods that consider defined material parameters in pattern construction. Project aims and objectives . investigations of the mechanical impact of pressure garments on the body with consideration of the material behaviors, the pattern construction and motion studies; . develop an objective measurement equipment to analyze the pressure on the surface of the body to define optimum range of pressure; . quantification of the blood circulation with a focus on the arms and legs due to a pressure garment; . optimize the production process of knitted fabrics with manufacturing engineering. Research deliverables (academic and industrial) Deliverables include research and conference papers, product collections, exhibitions and knowledge base. Publications None
Enschede, The Netherlands Textile Technology, Department of Chemical Engineering, University of Twente, P.O. Box 217, 7500 AE, Enschede, The Netherlands Tel: +31-(0)53-489 3596; Fax: +31-(0)53-489 3849; E-mail:
[email protected] or
[email protected] Dr. V.S. Moholkar, Textile Technology Research staff: Prof. Dr. ir. M.M.C.G. Warmoeskerken
Ultrasound enhanced mass transfer in wet textile processes Other partners: Academic None Project started: 1 July 1998
Industrial Stork Brabant, The Netherlands Project ended: 30 June 2002 (the project will be continued in 2003) Source of support: Stork Brabant, The Netherlands
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Keywords: Ultrasound, Enhanced mass transfer, Sono-process engineering, Cavitation, Process intensification One of the main problems in wet textile processes is the relatively slow transport processes in the porous structure of the textile substrate. Due to the complex geometry of textile materials these processes are mainly diffusion controlled. It is believed that ultrasonic waves can enhance these processes. The current project is aimed at understanding the mechanisms of ultrasound waves and their effect on the enhancement of the transport processes by inducing convective diffusion in the pores of textile materials. The mechanisms of ultrasound waves are being investigated in terms of acoustic cavitation phenomena and acoustic streaming. The theoretical analysis is supported by model experiments. Project aims and objectives The relatively slow transport processes in the porous structure of the textile substrate form one of the main problems in wet textile processes. Due to the complex geometry of textile materials these processes are mainly diffusion controlled. The aim of the project is to intensify the mass transfer process in the pores of textiles by acoustic cavitation. The focus of the project is on the mechanisms of ultrasound waves and their effect on the enhancement of the transport processes by inducing convective diffusion in the pores of textile materials. Publications Moholkar, V.S. (2002) ‘‘Intensification of textile treatments: sonoprocess engineering’’, PhD thesis, University of Twente, The Netherlands. Moholkar, V.S. and Warmoeskerken, M.M.C.G. (2000a), ‘‘Mechanistic studies in ultrasonic textile washing’’. AATCC Annual Book of Papers-2000 (CD-ROM version), Section 18, 1-8. Moholkar, V.S. and Warmoeskerken, M.M.C.G. (2000b), ‘‘Scale-up and optimization aspects of an ultrasonic processor’’, Proceedings of 21st Annual European AIChE Colloquium, AIChE NL-BE Section, pp. 59-66. Moholkar, V.S. and Warmoeskerken, M.M.C.G. (2001), ‘‘Intensification of mass transfer in textile materials’’, Proceedings of the 1st AUTEX Conference (Technitex), Povoa do Varzim, Portugal, June 26-29, 2001, pp. 204-13. Moholkar, V.S. and Warmoeskerken, M.M.C.G. (2002a), ‘‘The mechanism of ultrasonic mass transfer enhancement in textiles’’, Proceedings of the 2nd Autex Conference, Bruges, Belgium, 1-3 July, p. 561. Moholkar, V.S. and Warmoeskerken, M.M.C.G. (2002b), ‘‘Mechanistic aspects and optimization of ultrasonic washing’’. AATCC Review, Vol. 2 No. 2, pp. 34-7. Moholkar, V.S., Pandit, A.B., and Warmoeskerken, M.M.C.G. (1999), ‘‘Characterization and optimization aspects of a sonic reactor’’, Proceedings of the International Conference and Exhibition on Ultrasonics (ICEU-99), Ultrasonics Society of India, Vol. 1, pp. 17-22. Moholkar, V.S., Rekveld, S. and Warmoeskerken, M.M.C.G. (2000), ‘‘Modeling of the acoustic pressure fields and the distribution of the cavitation phenomena in a dual frequency sonic processor’’, Ultrasonics, Vol. 38, pp. 666-70. Moholkar, V.S., Huitema, M., Rekveld, S. and Warmoeskerken, M.M.C.G. (2002), ‘‘Characterization of an ultrasonic system using wavelet transforms’’, Chem. Eng. Sci., Vol. 57 No. 4, pp. 617-29.
Enschede, The Netherlands Textile Technology, Department of Chemical Engineering, University of Twente, P.O. Box 217, 7500 AE, Enschede, The Netherlands Tel: +31-(0)53-489 3596; Fax: +31-(0)53-489 3849; E-mail:
[email protected] or
[email protected] M. Lopez-Lorenzo M.Sc., Textile Technology Research staff: Prof. Dr. ir. M.M.C.G. Warmoeskerken, Dr. ir. V.A. Nierstrasz
Enzymatic upgrading of the properties of recycled paper fibers Other partners: Academic Technical Univ. Eindhoven, Wageningen Agricultural Univ.,
Industrial Kappa RP Europe, Sappi, So¨dra, Voith Sulzer, Buckman, DSM, Novozymes
ATO-DLO, KCPK, TNO Paper and Board Project started: 1 September 2000 Project ends: 31 August 2004 Finance/support: N/A Source of support: Ecology, Economy and Technology program (EET) from the Dutch Ministry of Economic Affairs Keywords: Cellulase, Enzyme technology, Cellulose, Surface modification It is expected that within 10 years the processes of textile production will be shifted substantially due to increasing governmental and environmental restrictions and the availability of fresh water. Enzyme technology is a promising technology to fulfill expected future requirements. In 1998 the Textile Technology Group has taken the initiative to start research on fundamental aspects on enzyme applications. This project focuses the surface modification of cellulose fibres. Paper is a non-woven material formed by cellulose fibres. The recycling of cellulose fibres is limited since the tensile strength decreases during this process. Generally, it is assumed that the deterioration of properties of recycled paper is mainly due to structural changes in the fiber cell wall caused by drying. The project aims to improve the tensile strength of recycled paper, for which different concepts for the surface modification of the fibres will be developed.
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Recycled fibers can be upgraded through enzymatic treatments of these fibers. Enzymatic hydrolysis of cellulose by cellulases can improve fibrillation and flexibility, enabling the formation of a fibre-network, which gives improved strength characteristics to the paper. Project aims and objectives The overall aim of the project is ‘‘fibre technology for a durable production of paper and board’’. Our task in this project is to minimise the decrease in the tensile strength of paper during the recycling process using enzyme technology. We will establish the connection between bonding and strength properties and how fibres are affected due to the enzymatic modification. Publications Lenting, H.B.M. and Warmoeskerken, M.M.C.G. (2001a), ‘‘Mechanism of interaction between cellulase action and applied shear force, an hypothesis’’, Journal of Biotechnology, Vol. 89 No. 2-3, 217-26. Lenting, H.B.M. and Warmoeskerken, M.M.C.G. (2001b), ‘‘Guidelines to come to minimized tensile strength loss upon cellulase application’’, Journal of Biotechnology, Vol. 89 No. 2-3, pp. 227-32. Lopez-Lorenzo, M., Nierstrasz, V.A. and Warmoeskerken, M.M.C.G. (2002a), ‘‘Enzymatic modification of cellulosic fibers: from lyocell to recycled paper’’, Book of abstracts of the 2nd International Symposium on Biotechnology in Textile Industry (INTB conference), Athens, Georgia, USA, 3-6 April, pp. 25-6. Lopez-Lorenzo, M., Nierstrasz, V.A. and Warmoeskerken, M.M.C.G. (2000b), ‘‘Enzymatic modification of cellulosic fibers: from lyocell to recycled paper’’, Proceedings of the 2nd Autex Conference, Bruges, Belgium, 1-3 July, p. 563.
Enschede, The Netherlands Textile Technology, Department of Chemical Engineering, University of Twente, P.O. Box 217, 7500 AE, Enschede, The Netherlands Tel: +31-(0)53-489 3596; Fax: +31-(0)53-489 3849; E-mail:
[email protected] or
[email protected] P.B. Agrawal M.Sc., Textile Technology Research staff: Prof. Dr. ir. M.M.C.G. Warmoeskerken, Dr. ir. V.A. Nierstrasz
Bioscouring of cotton fabrics Other partners: Academic TNO Textiles, TU Graz, UMinho, UPC Terrassa Project started: 1 December 2000
Industrial Textile Alberto de Sousa (Portugal), Tinfer (Spain) Project ends: 30 November 2004
Finance/support: N/A Source of support: EU 5th framework Keywords: Bioscouring, Enzyme technology, Cotton, Pectinase The traditional alkaline scouring process can be replaced with an enzymatic scouring process, in which impurities such as protein, wax and ash are efficiently removed prior to further processing of the cotton fabric. Our aim in this project is the development of a new environmentally and industrially viable (enzyme based) continuous process for the scouring of cotton. In order to design a stable enzymatic pre-treatment process, it is necessary to understand the structure of a cotton fiber that will help to make a targeted attack on non-celluloses. Due to the high substrate specificity of most enzymes it is necessary to have sufficient detailed information about the substrate composition and structure to design and introduce a robust pre-treatment process. On the basis of the structure of the cotton fiber an alternative process was proposed. Project aims and objectives The overall aim of this project is the development of a new environmentally and industrially viable enzymatic continuous and batch processes for the scouring of cotton fabrics. Publications Agrawal, P.B., Nierstrasz, V.A. and Warmoeskerken, M.M.C.G. (2002a), ‘‘Bioscouring of cotton textiles: the structure of cotton in relation to enzymatic scouring processes’’, Book of abstracts of the 2nd International Symposium on Biotechnology in Textile Industry (INTB Conference), Athens, Georgia, USA, 3-6 April, pp. 21-2. Agrawal, P.B., Nierstrasz, V.A. and Warmoeskerken, M.M.C.G. (2002b), ‘‘Bioscouring of cotton textiles: the structure of cotton in relation to enzymatic scouring processes’’, Proceedings of the 2nd Autex Conference, Bruges, Belgium, 1-3 July, p. 562. Lenting, H.B.M., Zwier, E. and Nierstrasz, V.A. (2002), ‘‘Identifying important parameters for a continuous bioscouring process’’, Textile Research Journal, Vol. 72 No. 9, 825-31.
Enschede, The Netherlands Textile Technology, Department of Chemical Engineering, University of Twente, P.O. Box 217, 7500 AE, Enschede, The Netherlands Tel: +31-(0)53-489 3596; Fax: +31-(0)53-489 3849; E-mail:
[email protected] or
[email protected] T. Topalovic M.Sc., Textile Technology Research staff: Prof. Dr. ir. M.M.C.G. Warmoeskerken, Dr. ir. V.A. Nierstrasz
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Catalytic bleach processes Other partners: Academic TNO Textiles, TNO Nutrition
Industrial Procede Twente B.V., Boessenkool B.V., TDV B.V., Emiod B.V., Vlisco Helmond B.V. Project ends: 30 October 2006
Project started: 1 November 2002 Finance/support: N/A Source of support: Ecology, Economy and Technology Program (EET) from the Dutch Ministry of Economic Affairs Keywords: Oxidative catalysts, Process intensification, Bleach In the traditional bleaching process high temperatures and high concentrations of peroxide are needed. In this recently honored project innovative bleach processes will be developed for the pre-treatment of textile materials using oxidative catalysts. Processes on the basis of oxidative catalysts can be performed at much lower temperatures (40 C) and with a significant reduction of the concentration of chemicals compared to the traditional process. In this project more environmentally acceptable and more efficient pre-treatment processes for textile materials will be developed on the basis of such oxidative catalysts. Project aims and objectives The aim of this project is the development and introduction of more environmentally acceptable and more efficient pre-treatment processes for textile materials on the basis of oxidative catalysts.
Enschede, The Netherlands Textile Technology, Department of Chemical Engineering, University of Twente, P.O. Box 217, 7500 AE, Enschede, The Netherlands Tel: +31-(0)53-489 3596; Fax: +31-(0)53-489 3849; E-mail:
[email protected] or
[email protected] Textile Technology Research staff: Prof. Dr. ir. M.M.C.G. Warmoeskerken, Dr. ir. V.A. Nierstrasz
Dynamic and advanced wetting of textile materials Other partners: Academic Industrial None None Project started: 1 May 1999 Project ended: – Finance/support: W/A Source of support: The Dutch Foundation for Technology of Structured Materials Keywords: Wetting, Dynamic surface tension, Contact angle, Nanotechnology, Surface heterogeneity, Surface roughness Wetting is key in transport processes in wet textile processing, like washing and dyeing. The knowledge of liquid flow through and the wetting of complex materials is often limited and the process conditions are usually chosen on an empirical basis, rather than a fundamental one. Recent advances in the characterization of surface properties of materials make it in principle possible to relate the macro- and meso-scopic properties of the textile to its nanoscopic properties, even under conditions far from equilibrium. In this project the inter relations between wetting properties, surface roughness, surface heterogeneity and adhesion forces will be studied. The Textile Technology Group has advanced facilities available such as an auto-porosimeter, equipment to measure the dynamic surface tension and high resolution ADSA equipment to measure dynamic and equilibrium wetting characteristics. Project aims and objectives The aim of this project is to generate fundamental knowledge about wetting phenomena in textile materials and to develop tools to predict the wetting behavior in wet textile processes. Publications Nierstrasz, V.A. and Warmoeskerken, M.M.C.G. (2002), ‘‘Dynamic wetting of textile materials’’, Proceedings of the 2nd Autex Conference, Bruges, Belgium, 1-3 July, p. 564.
I˙zmir, Turkey Engineering Faculty, Department of Textile Engineering, Ege University, E.U Mu¨h. Fak. Tekstil Mu¨h. Bo¨lu¨mu¨, 35100 Bornova, I˙zmir, Turkey Tel: 90-232-3887859; Fax: 90-232-3887859; E-mail:
[email protected] Prof. Dr. Is¸ık Tarakc¸iogˇlu, Department of Textile Finishing
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Research staff: Assistant Prof. E. Perrin Akcakoca (Ph.D.), Assistant Prof A. Taner O¨zgu¨ney (Ph.D.), Research Assistant Arzu Ozerdem (M.Sc.)
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An investigation of the application of RF dryer combined with steam as a reactor in textile pretreatment, dyeing and printing Other partners: Academic Industrial None None Project started: June 2002 Project ends: June 2003 Finance/support: 35,000 US$ Source of support: Textile Research Center of The Scientific and Technical Research Council of Turkey Keywords: Microwave energy, RF dryer, Reactive dyeing, Pretreatment of cotton, Reactive printing, Ager, Reactor High frequency HF energy has been used in industrial dyeing processes for a long time. Besides drying process it is also possible to make use of HF dryers as a reactor in pretreatment and dyeing processes. It was observed that, in the investigations carried out in our University, the usage of microwave combined with steam has given satisfying results. It was figured out that application of two-step microwave steam process (3 min+3 min=6 min dwell time) in pretreatments of cotton substrates has given results (desizing, absorbency, seed removal, degree of whiteness), which are equivalent to that of conventional two-step pad steam processes (10 min+10 min=20 min dwell time). In addition, it was observed that, in many cases, one-step microwave steam combination with 3–4 min dwell time has achieved adequate results. The appropriate results in reactive dyeing and printing was also obtained. These experiments were carried out in a kitchen type modified microwave oven (2,450 MHz). In this study the usability of a modified (direct steam feedable) continuous laboratory type RF (27.12 MHz) dryer as a reactor in the pretreatment of cotton fabrics and their dyeing and printing with reactive dyes will be investigated. Project aims and objectives In this study, it is aimed to reduce energy consumption and time saving by using the steam fed RF dryer as a reactor (ager) and consequently to reduce the manufacturing costs without decreasing quality. Research deliverables (academic and industrial) Experiments in progress
Publication Tarakcioglu, I., Anis, P. (1996), ‘‘Microwave processes for the combined desizing, Scouring and Bleaching of Grey Cotton Fabrics’’, Journal of Textile Institute, Vol. 87, pp. 602-8.
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Ege University, Textile and Apparel Research and Development Centre, 35100 Bornova, I˙zmir, Turkey Tel: +90 232 388 78 59; Fax: +90 232 388 78 59; E-mail:
[email protected] Prof. Dr. Is¸ık Tarakc¸iogˇlu, Ege University, Faculty of Engineering, Textile Engineering Department ¨ zgu¨ney, Research Research staff: Assistant Prof. Dr. Arif Taner O ¨ Assistant Arzu Ozerdem, Research Assistant Emrah Bilgin
A research about solving the problems of reactive printed rayon fabrics Other partners: Academic None
Research register
Industrial Ayboy Tekstil San. Ve Tic. A.S¸. 10037 Sok. No: 8 AOSB. C¸igˇli/I˙zmir Bati Basma San. A.S¸. Efes Cad. No: 1 Torbalı/I˙zmir Project end: 1 September 2002
Project started: 1 September 2000 Finance/support: $35,000 Source of support: The Scientific and Technical Research Council of Turkey Keywords: Viscose, Reactive dyestuff, Causticising, Urea, Moistening, Fixation Reproducibility and unevenness are the common problems for the prints of viscose fabrics and it makes the constitution of comprehensive research project, which will be carried out together with the necessary industry partnership. As the parameters that affect the print quality of reactive dyestuffs on viscose fabrics are investigated, the study has been mainly split into two parts. In the first part, the effects of the pretreatment and the other processes applied to the fabrics before printing have been examined. In the second part, the effects of the treatments applied to the fabrics during or following printing and the print paste contents have been investigated. The parameters, which are investigated in the first part of the study are causticising, bleaching, reductive treatment and impregnating with urea.
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The parameters investigated in the second part are moistening before and after printing, the amount and existence of urea in the print paste and fixation conditions. In each experiment, these factors are investigated with different levels and the outcomes are evaluated statistically. By this way, seven groups of experiment with different repeats have been performed. In all these experiments, Cibacron Red P 4B and Cibacron Blue P 3R with different molecular weights are used as dyestuffs. As a conclusion of all these full-sized and laboratory-sized experiments, processes and conditions, which will optimize qualities and costs, were tried to be determined by comparing the handle properties, tensile strengths, fastness rates and the color values of the printed fabrics. However, this project has been carried out by using only one type of viscose fabric with low sulphur content. This research project will continue to investigate the effect of different viscose types on the printing properties. Project aims and objectives The main purpose of this project is to investigate the parameters, which affect the reproducibility and the levelness of the viscose printing processes and by this way, to determine the optimum printing conditions. Research deliverables (academic and industrial) In relation with all the findings of the projects, the printers would be promoted with the following optimum process steps for both steaming and thermo fixing conditions separately: . For steaming conditions: desizing, causticising (8–10 Be), Padding with 150 g/l urea, printing (without urea), drying (120 C, 2 min), Fixation (102 C, 10 min) and washing off. . For thermo fixing conditions: desizing, causticising (8–10 Be), padding with 150 g/l urea, printing (100 g/kg urea), drying (120 C, 2 min), moistening (10 per cent), fixation (150 C, 5 min) and washing off. All these results are valid for the viscose fabrics with low sulphur content and the whiteness degree which is quite high after desizing. Publications None
I˙zmir, Turkey Engineering Faculty, Department of Textile Engineering, Ege University, E.U Mu¨h. Fak. Tekstil Mu¨h. Bo¨lu¨mu¨, 35100 Bornova, I˙zmir, Turkey Tel: 90-232-3887859; Fax: 90-232-3887859; E-mail:
[email protected]
Prof. Dr. Abbas Yurdakul, Department of Textile Finishing ¨ zen (M.Sc.), Research staff: Assistant Prof. Dr. E. Perrin Akc¸akoca, ˙Ilhan O Sima Sertso¨z (Textile Engineer), Meltem Argun (Technician)
Investigation of the parameters that effect wet fastness properties of the reactive dyed knitted fabrics Other partners: Academic None
Industrial Association of Textile Finishing Producers Pisa A.S¸. Ekoten A.S¸. Project ended: March 2002
Project started: September 2000 Finance/support: US$ 10,000 Source of support: Textile Research Center of The Scientific and Technical Research Council of Turkey Keywords: Fastness, Wet rubbing, Reactive dyes, Crockmeter, Mercerization, Finishing, Aftertreatment The textile industry is composed mainly of companies that develop, produce and/or distribute fabrics, or textile materials. With textiles and apparel having become a global industry balance of supply, and demand changed, as a result today customers are highly demanding. Reactive dyed knitted fabrics have a wide usage in textiles and these fabrics have a major share in Turkish textile and apparel exports. Increased customer demanding results in substantial amount of complaints related to the poor wet rubbing fastness in reactive dyed knitted fabrics particularly in dark shades of red, navy blue, bordeaux, black etc. This issue results in . second quality production and . high production cost. In addition, it effects the textile and apparel sales in international markets negatively. In this research the parameters which could be important for the wet rubbing fastness was investigated. The effects of the following parameters were examined: . pretreatment (bleaching), . mercerization, . washing processes, . aftertreatments (i.e. treatment with cationic fixation agents), . different cotton fiber origin.
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Project aims and objectives . Decreasing of the second quality production. . Developing ecological production. . Decreasing of the cost with non-decreased quality. Research deliverables (academic and industrial): Industrial conclusions . Increased activity of the pretreatment has no effect on wet rubbing fastness, so high exhaustion of the chemicals and long term process time are not needed in dark shades . Aftertreatment like treatment with cationic fixation agents does not bring about any significant improvement in wet rubbing fastness . Mercerization increases color yield and compared with unmercerized samples mercerized samples have ½ higher grade. In addition to achieve some shade, concentration of the dyes for mercerized samples is much little than that of unmercerized samples. This results in better wet rubbing grades. . Amount of washing scales does not change wet rubbing fastness grades. . Knitted fabrics with cotton fibers of different origins were examined and it was observed that type of the cotton fiber has no effect on wet rubbing fastness. . Although raising has no effect on wet rubbing fastness, emerising decreases wet rubbing fastness. . Wet rubbing fastness grades for the reactive dyed knitted fabrics are about 2–3 for dark shades and today, it is almost not possible to improve it, so researchers, dyestuff and textile producers must declare this issue to the customers. Publications Not available
I˙zmir, Turkey ¨ BI˙TAK TAM The Scientific and Technical Research Council TU ¨ niversitesi of Turkey Textile Research Center, Ege U ˙ ¨ TUBITAK Tekstil Aras¸tirma Merkezi, Bornova, I˙zmir TURKEY Tel: 90 232 3887859; Fax: 90 232 3887859; E-mail:
[email protected]
Prof. Dr. Kerim Duran, Faculty of Engineering, Textile Department, Ege University Research staff: Assistant Prof. Dr. Ays¸egu¨l Ekmekci, Emrah Bilgin, Cem Karabogˇa
Usage of ultrasound combined with hydrogen peroxide and UV light in textile wet processing Other partners: Academic Industrial Ege University, None Faculty of Engineering, Textile Department Finance/support: $30,124 ¨ BI˙TAK TAM Source of support: TU Project started: 1 August 2002 Project ends: 1 August 2003 Keywords: Cotton, Ultrasound, Washing, Hydrogen peroxide, UV light, Textile pretreatment It is very important to remove foreign matters from cotton because of quality of textile materials and success in following processes. Effective washing and pretreatment processes depend on three factors: . chemicals and auxiliaries, . mechanical effects, . parameters (temperature, time, materials, etc.). The use of ultrasound in textile finishing offers many potential advantages: . energy savings, . reduced processing times, . reducing environmental problems. In this project, ultrasound will be combined with hydrogen peroxide and UV light. New ultrasound equipment will be used in textile finishing. The project is the first part of great project. All the experiments are preparatory in this year. According to results of the experiments, main project will be expanded. Project aims and objectives . new textile finishing technology, . new ultrasound equipment for textile finishing, . energy savings in textile finishing,
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reducing environmental problems, reducing processing times.
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Publications None
Kaunas, Lithuania Faculty of Design and Technologies, Kaunas University of Technology, Studentu str. 56, Kaunas LT-3031, Lithuania Tel: +370 37 300205; Fax: +370 37 353989; E-mail:
[email protected] Dr. Eugenija Strazdiene Department of Clothing and Polymer Products Technology Research staff: Doctoral students J. Domskiene, V. Dobilaite, V. Sidabraite, K. Dapkuniene
The effect of physical-mechanical properties upon the tailorability and appearance of textiles Other partners: Academic Industrial None None Project started: 15 January 2002 Project ends: 15 January 2006 Finance/support: N/A Source of support: Kaunas University of Technology Keywords: Technical textiles, Mechanical properties, Laminates, Coating, Shearing, Buckling, Surface Roughness, Image analysis The research project is orientated towards modern textiles, which is characterized by new original properties extending their functionality and the range of their end use. Laminates and coatings bring textile technology into a new dimension. High performance fabrics are used for leisure, sports, industrial and military garments. In this sense woven structure is very attractive as the reinforcement for composites because it is lightweight, flexural and strong. This makes textile composites suitable for the parts of complicated or curved shape due to their formability properties. Though technical textiles are designed for a specific performance, aesthetics for such garments is very important, too. Thus the main goal of this research is to study the effect of shearing and buckling
properties for the behavior of technical textiles, especially for fitting such materials on three-dimensional surfaces without wrinkling and to analyze the conditions when these fabrics start to loose their stable shape, i.e. their surface becomes waved. Project aims and objectives An experimental method based on image capturing and image analysis able to characterize deformational properties of coated and laminated composites in uniaxial and spatial tensile deformations will be developed. Comparative analysis of buckling wave’s propagation, i.e. alterations of its shape (changes of image intensity in certain zone of the specimen) and dimensions (length, width and number of waves) in uniaxial tension of bias (45 ) orientated samples will be performed. Furthermore, the ability of coated and laminated textile composites to be deformed into three-dimensional curvature, i.e. to obtain spherical shape of different diameter will be analyzed from the standpoint of such properties as tensile extension, shear stiffness, shear hysteresis, bending rigidity and bending hysteresis. Research deliverables (academic and industrial) Theoretical results of this research will deepen the knowledge of technical textile mechanical behavior not only under in-plane and perpendicular loading conditions but also in spatial shape formation and will be used in textile and polymer garments design process. Publications Domskiene, J., Strazdiene, E. (2002a), ‘‘Shearing behavior of technical textiles’’, Material Science (Medziagotyra), Vol. 8 (in press). Domskiene, J., Strazdiene, E. (2002b), ‘‘Deformational properties of coated and laminated textile composites’’, Proceedings of the 2nd AUTEX World Textile Conference, Bruges, Belgium, p. 552. Domskiene, J., Strazdiene, E., Dapkuniene˙, K. (2002), ‘‘The evaluation of technical textiles shape stability by image analysis’’, Material Science (Medziagotyra), Vol. 8 (in press).
Kaunas, Lithuania Kaunas University of Technology, Faculty of Design and Technologies, Studentu str. 56, Kaunas-3031, Lithuania Tel: 370-7-767066; Fax: 370-7-353989; E-mail:
[email protected] Hab. Dr. Professor Matas Gutauskas Research staff: Dr L. Papreckiene, Dr V. Masteikaiste, doctoral students V. Daukantiene and E. Strazdiene
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Behavior evaluation and prognosis of textile and polymer material shells
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Other partners: Academic Industrial None None Project started: January 1997 Project ended: January 2002 Keywords: Deformation, Membrane, Polyethylene, Punch, Shell, Structure, Textile, X-ray diffraction The research deals with the specific area of materials science concerning clothing, packing and other heterogenic structures of polymer materials. The investigation is aimed to determine parameters of textile and other polymer materials behavior evaluation in biaxial deformation and to develop basis for its diagnosis and prognosis taking into account ambient conditions and acting loads of materials serve and processing. The investigation deals with the problem concerning the measurement and theoretical description of spatial shape of textile or polymer material shell obtained by various biaxial deformation methods. Besides, the investigation of interrelations between these biaxial deformations is to be carried on and the search for new methods and regimes of thin anisotropic polymer membrane formation will be made. Thus, the research seeks to define the relationship between acting loads, materials anisotropy, formed shell geometric parameters and resulting strains. The effect of textile material structure upon its spatial behavior is going to be examined, also. In addition, the assessment of friction factor between textile or polymer shell surface and deforming device will be given. Project aims and objectives A universal and comfortable experimental base for membrane and punch deformation tests must be created which will make it possible to investigate the behavior of different structure materials, i.e. membrane, woven or knitted materials and to reveal characteristic regularities of such processes and materials. Research deliverables (academic and industrial) The new experimental base of textile and polymer materials biaxial deformation is going to extend the existing laboratory of material testing and will be used in the study process of the University. Theoretical results of this research work will deepen the knowledge of materials spatial shape formation and will be used in textile and polymer garments design process.
Publications Daukantiene, V. and Gutauskas, M. (1997), ‘‘The influence of clamp geometry on polymer membrane punch deformation characteristics’’, Proc. of the Cone Design and Technology of Consumer Goods, Kaunas, pp. 201-5 (in Lithuanian). Daukantiene, V. and Gutauskas, M. (in press), ‘‘The performance in secondary structures of polyethylene membranes after uni/biaxial deformation process’’, Materials Science, Kaunas. Masteikaite, V. and Gutauskas, M. (1997), ‘‘Mechanical stability of fused textile systems’’, International Journal of Clothing Science and Technology, Vol. 9 No. 5, pp. 360-6. Strazdiene, E., Daukantiene, V. and Gutauskas, M. (in press), ‘‘The changes of polyethylene structure in shell forming process’’, Materials Engineering, Kaunas. Strazdiene, E., Gutauskas, M. and Williams, J.T. (1997), ‘‘Mechanical behavior prediction of spatial textile constructions’’, Proc. 2nd International IMCEP’97 Conference, Maribor, Slovenia, pp. 71-9. Strazdiene, E., Gutauskas, M., Papreckiene, L. and Williams, J.T. (1997), ‘‘The behavior of textile membranes in punch deformation process’’, Materials Science, Kaunas, Vol. 2 No. 5, pp. 50-4. Tijuneliene, L. and Gutauskas, M. (1998), ‘‘The geometry of punch formed thin shell and method of its determination’’, Proc. of the Cone Design and Technology of Consumer Goods, Kaunas, pp. 194-200 (in Lithuanian). Tijuneliene, L., Strazdiene, E. and Gutauskas, M. (in press), ‘‘The behavior of polyethylene membrane due to punch deformation process’’, Polymer Testing, Elsevier, Oxford.
Kaunas, Lithuania Kaunas University of Technology, Faculty of Design and Technologies, Studentu str. 56, Kaunas-3031, Lithuania Tel: 370-7-767066; Fax: 370-7-353989; E-mail:
[email protected], Department of Clothing and Polymer Products Technology Hab. Dr. Professor Matas Gutauskas Research staff: Dr E. Strazdiene, Dr L. Papreckiene, Dr V. Daukantiene and master student G. Martisiute
New method of textile hand evaluation Other partners: Academic Industrial None None Project started: June 2001 Project ends: December 2004 Keywords: Textiles, Membrane, Pulling through, Biaxial deformation, Geometry, Wave, Jamming
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Although a large part of textiles is concerned with imparting desirable physical properties, theoretical understanding of the effect of these properties on material response is limited. The research project will provide new method for the evaluation of planar anisotropic material’s behavior and original experimental information will be obtained, contributing to the existing knowledge in the field of mechanics of heterogenic, e.g. textile structures. New pulling through a hole method is similar to a well-known punch test used to control strength parameters of knitted material. The difference is that rounded specimen is not firmly fixed by its external contour and the diameter of the hole and the punch are relatively small compared to that of the specimen. Latest investigations have shown that this method is sufficiently informative and able to characterise such hand properties as softness, slippery, roughness, etc. Besides, it provides useful information for the evaluation of textile’s drape and anisotropy. Project aims and objectives The aim of the research is to set the relationship between the geometry and resistance parameters of textile membrane due to its type and testing conditions. Tests are performed by the original device mountable on the standard tensile testing machine. It consists of two perpendicular plates, replaceable stand with the hole in the centre and supporting plate with the hole of the same radius. Spherical punch is used to pull rounded specimen through the hole of the stand. The investigations are realised by two pulling through cases: free pulling through the hole of the stand; restrained pulling simultaneously through the limited crack of the plate and through the same hole of the stand. Research deliverables (academic and industrial) New testing method for textile and its experimental base will extend the existing laboratory of material testing and will be used in the study process of the Kaunas University of Technology. Theoretical results of this research will deepen the knowledge of textile spatial shape formation and will be used in textile and polymer garments design process. Publications Martisiute, G. and Gutauskas, M. (in press), New Approach to the Evaluation of Fabric Handle, Materials Science, Kaunas. Martisiute, G. and Gutauskas, M. (in press), ‘‘Pulling through process of knitted membrane: analysis of geometry’’, Proc. of the Conf. Design and Technology of Consumer Goods - 2001, Kaunas (in Lithuanian). Strazdiene, E., Martisiute, G., Gutauskas, M. and Papreckiene, L. (in press), ‘‘New method for the objective evaluation of textile hand’’, Journal of the Textile Institute, UK.
Kettering, UK Satra Technology Centre, Satra House, Rockingham Road, Kettering, Northamptonshire NN16 9JH Andrea Wilford, CTC
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Clothing comfort (intended) Other partners: Academic None Project started: – Finance/support: N/A Source of support: SATRA Keywords: Clothing, Design .
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Industrial None Project ends: Ongoing
A study of the factors important for comfortable clothing and development of a method to measure and assess comfort. To provide the clothing industry with a practical technique to quantify the comfort of clothing, highlighting strengths and weaknesses in design and making recommendations on how to improve the comfort of the garment. To provide guidance in product design, product manufacture and purchasing.
Project aims and objectives The development of a Clothing Comfort Index. A study of the factors important for comfortable clothing and to develop a practical technique for the quantification of clothing comfort. Academic deliverables Production of a Comfort Index System. Industrial deliverables A design guide for manufacturers and retailers to enable them to source materials and provide goods which meet consumer needs. Publication SATRA, ‘‘Clothing-Closeup’’.
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Kettering, UK Satra Technology Centre, Satra House, Rockingham Road, Kettering, Northamptonshire NN16 9JH. Austin Simmons, CTC Research staff: Mark Gamble
Swimwear degradations Other partners: Academic None Project started: June 1998 Finance/support: N/A Source of support: SATRA Keywords: Elastane, Swimwear
Industrial None Project ends: Ongoing
Limited wear trials were conducted on a variety of elastane-containing swimwear and examinations were carried out on a selection of failed swimwear garments. The common feature of each garment’s failure was the breakdown of the elastane component. In each case of failure it was noted that garments exhibited a particular pattern of wear. The project currently being undertaken aims to reproduce the wear patterns in a laboratory setting. It is intended to investigate the flow of swimming bath water through the fabric structure of different garments and the effect of flow restriction in preserving the life of a garment. It is also intended to develop a test rig for assessing the effects of combined chemical and mechanical action on swimwear garments. Project aims and objectives To establish an effective means of assessing the likely wear performance of elastane-containing swimwear. The means of assessment to incorporate a chemical and mechanical system for degrading swimwear materials. Academic deliverables An understanding of the mechanisms which contribute to elastane failure in swimwear garments. Industrial deliverables A test apparatus for predicting garment performance. Publication SATRA, ‘‘Clothing-Closeup’’.
Kettering, UK Satra Technology Centre, Satra House, Rockingham Road, Kettering, Northamptonshire NN16 9JH Andrea Wilford, CTC Research staff: David McKeown, Mark Gamble
Water-resistant permeable membranes Other partners: Academic None Project started: – Finance/support: N/A Source of support: SATRA Keywords: Garments, Wear
Industrial None Project ends: Ongoing
Limited wear trials have been undertaken on a series of commercially available garments which incorporate membrane structures. The results of this testing, which may be advanced to moisture and temperature recording of wear trialled products, using data-loggers, will be made available to SATRA members. Much of the work that is to be undertaken will complement SATRA’s current Comfort Index work. Project aims and objectives To understand the mechanisms at work in water permeable membranes which are used for clothing. We aim to draw on the expertise developed in the use of such materials in footwear. Academic deliverables To develop performance guidelines for current market products. Industrial deliverables To provide a service to industry for the development of membrane materials (and their testing). Publication SATRA, ‘‘Clothing-Closeup’’.
Kowloon, Hong Kong The Hong Kong Polytechnic University, Yuk Choi Road, Hung Hom, Kowloon, Hong Kong Tel: 852-27666525; Fax: 852-27731432; E-mail:
[email protected]
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Dr Winnie Yu, Professor Edward Newton, Institute of Textiles and Clothing, Apparel Research Laboratory Research staff: Miss Cherie Chan
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Conceptual model of intimate apparel design Other partners: Academic Industrial None Sunikorn Knitters Limited Project started: 19 October 1999 Project ended: 18 October 2001 Finance/support: $995,700 Source of support: Area of Strategic Development Fund Keywords: Conceptual model, Intimate apparel, Lingerie, Design, Process The goal of any conceptual design of garment is to add value. There is an increasing interest in using hi-tech fiber, functional fabric, seamless construction, new color, trimmings, fasteners and special fit. The introduction of new design into ladies’ intimate apparel becomes more fashion-oriented. However, companies always find difficulty in recruiting qualified and experienced designers. It takes excessive time to train the new blood, with lots of trials and errors. Intimate apparel is so complex that it requires multi-functions of comfort, stretch, shaping, protection, support and durability as well as aesthetic match with the outer-garments, at a moderate price. No systematic model is available in the industry for the designers to handle the necessary information such as material cost, product trend, consumer needs and market change for their commercial design. This project proposes to develop a conceptual model for intimate apparel design, with an overall aim of providing an intelligent system for making creative design with practical concerns. As a consequence, a company can take advantage of reducing the developing cost by using a conceptual model and well-structured information system for intimate apparel design. Project aims and objectives This project is proposed to achieve four specific objectives as follows: (1) to examine the existing concepts, information flow, technical process and working methods in designing intimate fashion; (2) to build up an architecture for intelligent support of intimate apparel design with knowledge database;
(3) to rationalize the process of commercial design including fashion inspiration, sketching, color mix, material selection, fabric testing, pattern cutting, sample fitting, sizing and product engineering; and (4) to develop and test the effectiveness of a new integrative conceptual model for intimate apparel design. Research deliverables (academic and industrial) Conference paper, research paper, model for intimate apparel design. Publications Chan, Y.C., Yu, W.M. and Newton, E. (2000a), ‘‘A discussion on bra inventions’’, Journal of Fashion Marketing and Management, June. Chan, Y.C., Yu, W.M. and Newton, E. (2000b), ‘‘Evaluation and analysis of bra design’’, Journal of Fashion Marketing and Management, October.
Kowloon, Hong Kong The Hong Kong Polytechnic University, Yuk Choi Road, Hung Hom, Kowloon, Hong Kong Tel: 852-27666525; Fax: 852-27731432; E-mail:
[email protected] Dr Winnie Yu, Dr Roger Ng, Institute of Textiles and Clothing, Apparel Research Laboratory Research staff: Mr Sunny Yan, Mr Wilson Lui, Rapid Product Prototyping Syndicate, Ms Sandy To, Ultra Precision Machining Centre
Advancement of moire´ body scanner and 3D visualization Other partners: Academic Industrial East China University Jeanswest International Project started: 15 March 2000 Project ended: 31 January 2001 Finance/support: $1,997,000 Source of support: Industrial Guided Applied Research & Development Keywords: Body scanner, Moire´ topography, Visualization, 3D, Pattern The project is divided into four phases.
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Phase 1: Enhancement and commercialization of single moire´ scanner A single moire´ scanner for capturing the human leg has been developed in our laboratory. To commercialize this novel product, the hardware will be packaged with an attractive design of housing, integrated with all optical components. The software program will be enhanced in accuracy and speed. The hardware is tested extensively to check if optical/mechanical refinement is required. The practical needs in the industry will be investigated through market survey and tests on various human figures. Then an attempt will be made to commercialize it based on market needs. Phase 2: Optical advancement of moire´ topography Based on our experience, further research can be made on optical advancement to increase the moire´ fringe visibility. The work includes a feasibility test of using flash light, optimization of the grid pitch, increase of CCD resolution, using macro design lens, installation of film cartridge at focal plane, enlarging the scanning format, improvement of hardware mechanism, and making even light brightness. Phase 3: Development and commercialization of a multi-head body scanner In this stage, an advanced version of multi-head body scanner will be developed. Light is projected through high density grid on to the body by flash tubes for quick shots. The images can be simultaneously transferred into a computer for fringe analysis. The 3D data are then used to map a body surface and the required body dimensions will be extracted by computer program. Phase 4: Visualization of 3D human body A software program will be developed to perform the following tasks: . generate virtual human body using the 3D data cloud; . project a virtual garment on the virtual mannequin; . project texture on to the virtual garment; . display the 3D images on the monitor; and . produce garment patterns based on built-in procedure or using 3D pattern mapping method. Project aims and objectives It is aimed to design and develop several sets of single-head and multi-head body scanner with six ‘‘S’’ features - small, slim, saving, swift, simple, and safe. The specific objectives are: . to enhance the optical system of moire´ topography; . to improve the image processing;
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to provide a quick and realistic visualization of captured image; and to develop and commercialize the body scanner.
Research deliverables (academic and industrial) Upon completion of this project, the following deliverables will be provided: . An innovative design of half body scanner made with six ‘‘S’’ features – small, slim, saving, swift, simple and safe. . Professional service to the clothing industry regarding body scanning and its related applications. . Optical advancement of moire´ topography that contributes a low-cost method for non-contact measurement which can be used for body shape analysis, evaluation of clothing appearance and garment fit. . Semi-automatic/automatic moire´ image analysis system. . 3D visualization of captured image for better product development and adding value to apparel retailing. Patent to be filed . New optical design of moire´ camera with wide coverage, short image capturing and high resolution in short distance. . New photographic chemical process to obtain high-density range and high transparency for photographic grid plane. Publications Gu, H., Yu, W.M., Yan, S., Ng, K. and Hu, J. (2000), ‘‘Image improvement and fringe analysis of a moire´ body measurement system’’, World Automation Congress, 3rd International Symposium on Intelligent Automation and Control, Maui, Hawaii, June 11-16, Article number ISIAC048, ISBN: 1-889335-10-Xn. Yu, W.M. (1999a), ‘‘3D body scan – a new measure of size and shape’’, ATA Journal, October/November, pp. 69-70. Yu, W.M. (1999b), ‘‘3D body scanning and custom-fit apparel’’, Journal of Textile Research, Vol. 3, pp. 156-9. Yu, W.M. (2000), ‘‘Fit evaluation of men’s jacket using moire´ topography’’, Textile & Clothing, Vol. 12 No. 2, March. Yu, W.M., Yan, S. and Gu, H.B. (1999), ‘‘Design of 3D body scanner for apparel fit’’, Proceedings of the 5th Asian Textile Conference, September, pp. 400-3.
Kowloon, Hong Kong The Hong Kong Polytechnic University, Yuk Choi Road, Hung Hom, Kowloon, Hong Kong. Tel: 852-27666525; Fax: 852-27731432; E-mail:
[email protected]
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Dr Winnie Yu, Professor Xiao-ming Tao, Dr Jin-tu Fan, Dr Zhi-min Zhang, Institute of Textiles and Clothing, Apparel Research Laboratory Research staff: Mr Xiao-ming Qian, Ms Xiao-ning Jiao
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Product innovation of comfort stretch/pressure garment Other partners: Academic Jockey Club Rehabilitation
Industrial Triumph International Engineering Centre Project ended: 31 December 2001
Project started: 1 January 2000 Finance/support: $995,700 Source of support: Area of Strategic Development Fund Keywords: Comfort, Stretch garment, Pressure, Sensory, Shape
The effect of body shape on the wearing pressure was seldom studied. There is a lack of understanding of the optimum range of pressure distribution, stationary and dynamically, for different types of products, body sizes and shapes, as well as different ages of consumers. No work was made on the performance deterioration of the pressure garments in terms of shaping power and comfort after repeated use. This project initiates an integrative approach to study the consumer market of the pressure foundation garment, the existing product limitation and the actual functional requirement for different body shape. These will then be transferred to the ideas for fabric, pattern and production design. The product quality will then be evaluated in terms of sensory comfort, static and dynamic pressure, shape-up effect and wearing performance. Project aims and objectives This project proposes to develop a comfortable and high performance foundation garment that provides adequate pressure distribution to achieve good appearance and body feel. Specific aims are to: . analyse the customer needs and market potentials; . examine the functional performance of selected pressure foundation wear during wear; . identify the functional requirements and problems; . develop a model to test and redesign the warp knit fabric’s performance in providing optimal pressure and extensibility; . analyse the human body shapes with a focus at the waist to abdomen segment;
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determine the pressure and comfort requirement to induce the desirable shape-up effect on the body; design the fashion style and pattern to achieve desirable body comfort and shaping functions; develop an objective system to evaluate the overall function of pressure, body shape and wear comfort; and optimise the production process with manufacturing engineering.
Research deliverables (academic and industrial) Deliverables include review papers, research papers, conference papers, register patents for pressure analysis instruments, product collections, exhibitions and knowledge base. Publication Yu, W.M. (2000), ‘‘Special functions and market potential of intimate apparel’’, ATA Journal, October/November.
Kyeongsan, Korea School of Textiles, Yeungnam University, 214-1 Daedong Kyeongsan, Korea Tel: 82-53-8102771; Fax: 82-53-8125702; E-mail:
[email protected] Seung-Jin Kim, Textile Processing Lab Research staff: K.S. Park, S.B. Sim, S.Y. Kim, M.Y. Park
Comparison of physical properties of PET produced in domestic and foreign industries for enhancing fabric quality Other partners: Academic Industrial None S. H. Jeong Hanyang University Project started: 1 May 2002 Project ends: 31 December 2002 Finance/support: US$ 11,000 Source of support: FITI Testing and Research Institute Keywords: POY, FDY, Layer, Fineness, Thermal shrinkage, Thermal stress, Modulus This project surveys present status of quality on the polyester filament yarns (POY and FDY) which is used in Korean weaving industry. For this purpose,
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three POY (120d/36f, 50d/24f and 75d/36f) and FDY (118d/36f, 120d/36f, 120d/72f, 54d/36f, 50d/24f and 75d/36f) are selected. Nineteen filament manufactures in domestic and eight filament manufacturers in foreign countries such as China, Taiwan and Japan are also selected as companies of filament specimens. All specimens (cake state) are divided by 20 layers, the physical properties of each layer’s filament are measured and analysed with comparison between layers and manufacturers. The physical properties measured are fineness, thermal shrinkage (wet and dry), modulus, breaking stress and strain, thermal stress. And weaving preparatory and texturizing process conditions are predicted through analysis of these experimental results. Project aims and objectives . Enhancing fabric quality. . Counterplan of fabric streaky phenomena in synthetic fabrics. . Inducement of quality assurance in domestic filament manufacturers. Academic deliverables . One or more graduate theses. . Presentation to seminar as a paper. Industrial deliverables . Research report is delivered to small and medium weaving preparatory companies and seminar is held to them. Publications Kim, S.Y., Kim, S.J., Sim, S.B. and Park, M.Y. (2002), ‘‘A study on variation of physical properties of the PET FDY filament yarns between domestic and foreign’’, Proceedings of the Korean Textile Conference (submitted). Park, M.Y., Kim, S.J., Sim, S.B. and Kim, S.Y. (2002), ‘‘A study on variation of thermal shrinkage in layer of the PET filament yarns between domestic and foreign’’, Proceedings of the Korean Textile Conference (submitted). Park, K.S., Sim, S.B., Kim, S.Y., Park, M.Y. and Kim, S.J. (2002), ‘‘A study on variation of physical properties of the PET POY filament yarns of domestic and foreign’’, Proceedings of the Korean Textile Conference (submitted).
Kyeongsan, Korea School of Textiles, Yeungnam University, 214-1 Daedong Kyeongsan 712-749, Korea Tel: 82-53-8102771; Fax: 82-53-8125702; E-mail:
[email protected]
Seung-Jin Kim Textile Processing Laboratory Research staff: K.S. Park, S.B. Sim, S.Y. Kim, M.Y. Park
Development of easy-care worsted fabric using drawn worsted yarns Other partners: Academic Industrial None None Project started: 1st March 2002 Project ends: 28 February 2003 Finance/support: US$ 50,000 Source of support: Ministry of Science and Technology Keywords: Easy-care, Drawn worsted yarns, Anti-shrinkable, Twist, Drawing temperature This project covers development of easy-care worsted garment using drawn worsted yarns. For this purpose, various chemical treatment technology are applied for marking drawn worsted yarns. The chemical treatment technology includes anti-shrinkable technology and various chemical agent treatment recommended by WRONZ in New Zealand. The optimum processing condition such as yarn twist, drawing temperature, drawing time and yarn count on the drawing machine for easy care clothing are surveyed and analysed. Finally the physical properties of garment are measured and discussed with the various processing conditions of draw worsted yarns. Project aims and objectives . Development of antipilling worsted drawn yarns. . Development of easy-care worsted fabrics and garment. Academic deliverables . One or more graduate theses. . Presentation to seminar as a paper. Industrial deliverables . Manufacturing procedures for implant for making textile goods. Publication Lee, D.H., Kim, S.J. and Seo, O.K., ‘‘Changes in the properties of wool fibres, yarns and fabrics by finedrawing of worsted yarns’’, Extended Abstracts of the 31st Textile Research Symposium at Mt. Fuji, Textile Science Research Group in Text. Mac. Soc. of Japan, August, 2002, p. 24.
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Kyeongsan, Korea School of Textiles, Yeungnam University, 214-1 Daedong Kyeongsan 712-749, Korea Tel: 82-53-8102771; Fax: 82-53-8125702; E-mail:
[email protected] Seung-Jin Kim, Textile Processing Laboratory Research staff: None
Strategic direction on the progress of the Daegu textile industry Other partners: Academic Industrial None None Project started: 1 May 2002 Project ends: 31 December 2002 Finance/support: US$ 15,000 Source of support: Ministry of Commerce, Industry and Energy; Taegu-Kyeongbuk Silk and Synthetic Weaving Industrial Corporation Keywords: Daegu textile industry, R&D infra structure, Networking, Marketing This project is planning to make a strategy for the progress of the Daegu textile industry. This project covers a strategy for using the R&D infra structure, which is constructed in Milano Project. For this purpose, the present status of the synthetic textile industry in China and Japan are surveyed and networking system between various SME of textiles and textile research centers such as KTDI, DYETECH, KITECH and FCK in Korea is systemized. Especially the other infra system related to the technology and marketing is proposed for the progress of small and medium textile companies around Daegu area in Korea. Project aims and objectives . Set-up of strategy for the progress of Daegu textile industry. . Set-up of strategy for marketing infra structure for SME of textile around Daegu area in Korea. Academic deliverables . Presentation to seminar as a paper.
Industrial deliverables . Research report is delivered to small and medium weaving and yarn preparatory companies and seminar is held for them. Publications None
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Kyeongsan, Korea School of Textile & Fashion, Yeungnam University, 214-1 Daedong, Kyeongsan, Korea Tel: (053) 810 2536; Fax: (053) 812 5702; E-mail:
[email protected] Seung Jin Kim, Textile Processing Lab Research staff: J.W. Kim, K.S. Park, J.S. Yu, S.D. Hong, Y.S. Kim, B.K. Seo
Development of PET/staple composite knitted yarns and fabrics using disk twist device Other partners: Academic
Research register
Industrial S.I. Shin Project ended: 30 June 2001
Project started: 1 July 2000 Finance/support: US$17,000 Source of support: Ministry of Commerce, Industry and Energy Keywords: Disk twist devices, Viscose rayon, Pre-twist, Post-twist, Composite yarns, Circular knitting, Weft knitting The objective of this project is to develop the disk-twist device and the PET/staple composite yarns using this disk-twist device. First, the various disktwist devices such as various engraved shapes on the navel in the open-end rotor spinner are made and attached on the winder. Filaments used were viscose rayon 150d and polyester 70d/24f; 40 specimens are prepared using various disk-twist devices and disk vibrating conditions. These specimens are processed on the pretwist and post-false twist machines with processing conditions of S618/Z2200 and heat temperature 200 C. The physical properties of these specimens are measured and discussed with various disk-twist devices and processing conditions. The optimum conditions for good yarn physical properties are decided and the knitted fabrics with composite yarns produced under the optimum conditions are made using circular and weft knitted machinery.
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Project aims and objectives . Development of disk-twist device and application to filament twisting on winder. . Development of knitted yarns and fabrics using this disk-twist device.
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Academic deliverables . One or more graduate theses. . Presentation to seminar as a paper. Industrial deliverables . Manufacturing procedures for implant for making textile goods. Publication Kim, S.J., Shin, S.I., Kim, T.H., Son, J.H., Kim, J.W. and Park, K.S. (2000), ‘‘Development of PET/staple composite knitted yarns and fabrics using disk-twist device’’, Proceedings of the Korean Textile Conference, Vol. 33 No. 1, pp. 145-8.
Kyeongsan, Korea School of Textile & Fashion, Yeungnam University, 214-1 Daedong, Kyeongsan, Korea Tel: 82-53-8102536; Fax: 82-53-8125702; E-mail:
[email protected] Seung-Jin Kim, Textile Processing Lab Research staff: S.B. Shin, S.Y. Kim, M.Y. Park
A study of optimum production condition for the development of the PET composite yarns for knitted fabrics Other partners: Academic Industrial Tae Hoon Kim B.H. Ahn, K.Y. Kim Project started: 1 March 1999 Project ends: 28 February 2002 Finance/support: US$35,000 Source of support: Ministry of Science & Technology; Nine small and medium textile companies Keywords: Knitted yarns and fabrics, PET composites yarns, Pre-twist texturing M/C, Bulkiness of knitted fabrics
This project is aiming to develop knitted yarns and fabrics using PET composites yarns such as PET/Acryl, PET/Acetate, PET/Rayon and PET/natural yarns. This project includes the development of optimum production condition on the composite yarn manufacturing machineries such as pre-twist texturing machine and blend twisting machine of two or threefold yarns. Using these yarns, knitted fabrics are made and the bulkiness of knitted fabrics are measured and discussed with various knitted yarns, and optimum knitted yarn manufacturing conditions are decided. Project aims and objectives Objective of this project is to develop knitted yarns and fabrics of PET/PET, PET/Acryl, PET/Acetate, PET/Rayon and PET/natural yarns using pretwist texturing machinery. The optimum production conditions for the best knitted fabrics are decided and discussed with relation to various knitted yarns. Academic deliverables . one or more graduate theses; . presentation to seminar as a paper. Industrial deliverables . manufacturing procedures for implant for making textile goods. Publications Han, W.H., Lee, S.H., Lee, S.J., Noh, T.C. and Kim, S.J. (2001), ‘‘Effect of processing conditions of ITY on the physical properties of compound yarn for new synthetic fabrics (II)’’, Journal of the Korean Society of Dyers and Finishers, Vol. 13 No. 2, pp. 49-54. Hong, S.D., Kim, S.J., Seo, B.K., Sim, S.B. and Kim, J.W. (2001), ‘‘Effect of fabric manufacturing process characteristics on the PET handle for clothing’’, Proceedings of the Korean Society for Clothing Industry, pp. 130-4.
Kyeongsan, Korea School of Textile & Fashion, Yeungnam University, 214-1 Daedong, Kyeongsan, Korea Tel: 82-53-8102536; Fax: 82-53-8125702; E-mail:
[email protected] Seung-Jin Kim, Textile Processing Lab Research staff: K.S. Park, J.S. Yu, B.K. Seo, S.D. Hong, Y.S. Kim
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A study of optimum production condition for the development of the composite yarns and fabrics for the natural/PET garment Other partners: Academic Industrial None W.H. Han, T.C. No, M.S. Lee Project started: 1 March 1999 Project ended: 28 February 2002 Finance/support: US$58,000 Source of support: Ministry of Science & Technology; 15 small and medium textile companies Keywords: Weaving preparatory m/c, 2-for-1 twister, Winder, Yarn texturing, Composite twister, Thermal shrinkage, Thermal stress, Yarn bulkiness The objective of this project is to develop attachment of weaving preparatory machinery such as 2-for-1 twister, winder, yarn texturing machinery, twister and composite twister for developing the composite yarns and fabrics for natural/PET garment. In addition, the optimum processing conditions such as yarn tension, guide position, over feed and yarn feed speed are surveyed with various natural/PET composites yarns such as Viscose/PET, Cotton/PET, Rayon/PET, Wool/PET and Acryl/PET. And the various physical properties of the composite yarns such as thermal shrinkage, thermal stress, tensile modulus, yarn bulkiness and elastic recovery are measured and discussed with various processing conditions. Using these yarns, fabrics are made and their physical properties are measured and discussed with various yarn properties. Project aims and objectives This project aims to develop attachment of 2-for-1 twister, winder, yarn texturing machine, ordinary twister and composite twister for composite yarns. And optimum processing conditions are decided for these weaving preparatory machines. Academic deliverables . one or more graduate theses; . presentation to seminar as a paper. Industrial deliverables . manufacturing procedures for implant for making textile goods. Publications Hong, S.D., Kim, S.J. and Park, K.S. (2001), ‘‘Effect of the manufacturing process characteristics of PET fabrics on the clothing sensibility’’, Proceeding of the 2001 Spring Conference of Korean Society for Emotion & Sensibility, p. 23.
Park, K.S., Kim, S.J., Yu, Z.S., Kim, Y.S, Kim, S.Y. and Park, M.Y. (2001), ‘‘Effect of fabric manufacturing process characteristics on the sewability of PET garment’’, Proceedings of the Korean Society for Clothing Industry, pp. 125-9.
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Kyeongsan, Korea School of Textile & Fashion, Yeungnam University, 214-1 Daedong, Kyeongsan, Korea Tel: 82-53-8102536; Fax: 82-53-8125702; E-mail:
[email protected] Seung-Jin Kim, Textile Processing Lab Research staff: B.K. Seo, S.D. Hong, S.B. Sim
Development of knit and woven fabrics using drawn worsted yarns and their drawing system Other partners: Academic Industrial None O.K. Seo Project started: 1 July 2001 Project ended: 30 June 2003 Finance/support: US$24,600 Source of support: Ministry of Commerce, Industry & Energy Keywords: Worsted drawing yarns, Silk-like worsted yarn, Drawing ratio, Heating temperature This project surveys manufacturing technology of the silk-like worsted yarns and fabrics, and includes development of the drawing system of worsted staple yarn. Using this drawing system, optimum drawing ratio and temperature are decided. Fine staple worsted yarns (100 Nm) are made from 66 Nm and 52 Nm staple worsted yarns using the drawing system. The optimum conditions in the drawing process such as drawing ratio and temperature for linen-like and silklike knitted fabrics are decided through various experiments. The physical and mechanical properties of the specimens of the yarns and knitted fabrics are measured and discussed with various processing conditions in the drawing system. The yarn physical properties measured are thermal shrinkage, snarl index, bending rigidity, torsional rigidity, and fabric mechanical properties are tensile, bending, shear, compression and surface.
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Project aims and objectives Objectives of this research are to develop the linen-like and/or silk-like worsted yarn for knitted fabric. Also this project aims at the development of drawing machinery for worsted yarns, which is available to control draw ratio and drawing temperature, and includes the determination of the optimum twist condition. Academic deliverables . one or more graduate theses; . presentation to seminar as a paper. Industrial deliverables . manufacturing procedures for implant for making textile goods. Publications None
Kyeongsan, Korea School of Textile & Fashion, Yeungnam University, 214-1 Daedong, Kyeongsan, Korea Tel: 82-53-8102536; Fax: 82-53-8125702; E-mail:
[email protected] Seung-Jin Kim, Textile Processing Lab Research staff: B.K. Seo, S.D. Hong, S.B. Sim
Strategic direction on the research and development of technical textiles in Korean textile industry Other partners: Academic Industrial Tae Hoon Kim H.J. Jang Project started: 1 September 2001 Project ends: 31 December 2001 Finance/support: US$23,000 Source of support: Ministry of Commerce, Industry and Energy; Taegu-Kyeongbuk Silk & Synthetic Weaving Industrial Cooperation Keywords: Technical textile, Over-production, Garment oriented textile goods
This project surveys strategic direction on the research and development of technical textiles in Korean textile industries, especially in Daegu-Kyeongbuk textile region. For this purpose, first, the present industry status on the technical textiles in Taegu-Kyeongbuk region is surveyed including the status of technical textiles in the whole of Korea. The present status of advanced countries in relation to the technical textiles of the USA, European countries and Japan is also examined with technical textile goods of various famous companies. Finally, manufacturing field and goods with their own manufacturing facilities of textile industries in Taegu-Kyeongbuk region are recommended and predicted for distributing their production facilities and refraining from over-production of garment oriented textile goods. Project aims and objectives . survey on possibility of production of technical textiles with production facilities for the garment textile goods; . distribution of production facilities for the garment oriented textile goods; and . refraining from over-production of garment oriented textile goods. Academic deliverables . one or more graduate theses; . presentation to seminar as a paper. Industrial deliverables . research report is delivered to small and medium weaving and yarn preparatory companies and seminar is held to them. Publications None
Kyoto, Japan Kyoto Institute of Technology, Faculty of Textile Science, Matsugasaki Sakyo-ku, Kyoto, 606 Japan Tel: (075) 724 7846; Fax: (075) 724 7800 M. Nakamura, T. Matsuo and M. Nakajima, Department of Polymer Science and Engineering
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Analyses of tuft forming at bale opener Other partners: Academic None Project started: April 1994 Keywords: Simulation, Tuft, Yarns
Industrial None Project ends: To be continued
The purpose of the bale opener is to open the bale and to produce fine and uniform size tufts for the sequential process of yarn spinning. The opening mechanism at the tuft forming process was investigated, based on theoretical analyses of macroscopic mass balance and of tooth edge locus, and two experimental model tests. A theoretical model of microscopic mass balance was presented to simulate the opening process. Numerical calculations for several process conditions were carried out using the experimental results of model tufting studies. These simulation results have proved to be a good tool for better understanding of the process. The effect of good tuft forming by bale openers on the processibility of the sequential process of yarn spinning and the quality of yarn thus produced was also investigated through production tests of real mills. Project aims and objectives (1) To clarify the opening mechanism at the tuft forming process of the bale opener. (2) To establish simulation technology for the processing. (3) To investigate the effect of good tuft formings by bale openers on the processibility of the sequential process of yarn spinning, and the quality of yarn thus produced. (4) To pursue means towards the improvement of the bale opener. Industrial deliverables Refer to the publication. Publication Nakamura, M., Matsuo, T. and Nakajima, M. (1997), Journal of Textile Machinery Society.
Kyoto, Japan Kyoto Institute of Technology, Faculty of Textile Science, Matsugasaki Sakyo-ku, Kyoto, 606 Japan Tel: (075) 724 7846; Fax: (075) 724 7800 M.N. Suresh and T. Matsuo, Department of Polymer Science and Engineering
Development of total material design system of woven fabrics for apparel use Other partners: Academic M. Nakajima
Industrial T. Harada M. Inoue Project started: September 1994 Project ends: To be continued Keywords: Apparel, CAD, Fabric, Woven fabrics Although much research has been done on colour/pattern designing related to fabric appearance and fashion, material design technology for apparel fabrics is still in the developmental stage. A review shows that the past 20 years have witnessed the efforts towards trial construction of partial design systems and conceptualization of total material design logic. The main aim of this part in the series of our studies is to construct a fundamental logical structure of the computer-assisted total material design system for general apparel woven fabrics. The main components of the structure thus constructed and their functions are defined. The system consists of three sections: a user interface, the five design stages starting from conceptual design up to the detailed manufacturing design, and different types of databases which support the design stage. The format and contests of important system components are explained with examples. The executional logic of the system and its flow is also presented with a methodology to find a suitable design solution. Utilization of a ‘‘reference sample’’ has been introduced to simplify the design procedure. Some detailed case studies to illustrate application of this system have been carried out. The frame of the computer system is also being developed. Project aims and objectives To develop a ‘‘computer-assisted total material design system of woven fabrics for apparel use’’. Academic deliverables Refer to the publications. Publications Matsuo, T. and Suresh, M.N. (1997), Textile Progress. Suresh, M.N., Matsuo, T. and Nakajima, N. (1997a), Proceedings of IV Congress ATC, Taipei. Suresh, M.N., Matsuo, T. and Nakajima, N. (1997b), Journal of Text. Mac. Soc., Vol. 50, T146. Suresh, M.N., Matsuo, T. and Nakajima, N. (1997c), Proceedings of 25th Textile Research Symposium, Mt Fuji, Japan. Suresh, M.N., Matsuo, T. and Nakajima, N. (to be published), Journal of Text. Mac. Soc.
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Kyoto, Japan Kyoto Institute of Technology, Faculty of Textile Science, Matsugasaki Sakyo-ku, Kyoto, 606 Japan Tel: (075) 724 7846; Fax: (075) 724 7800 D.A. Alimaq and T. Matsuo, Department of Polymer Science and Engineering
Sensory measurements of fabric hand/mechanical properties: part I – worsted fabrics; part II – knitted fabrics Other partners: Academic Industrial M. Nakajima T. Harada Project started: April 1993 Project ends: To be continued Keywords: Fabric, Knitwear, Sensory measurement, Worsted Systems of instrumental method for measuring fabric hand have been fairly successfully developed like KES and its basic way has been well established. On the contrary, systems of sensory method have remained controversial. In this paper, a practical sensory method is proposed on the basis of analogy to sensory colorimetry. Measurement of two kinds of worsted fabrics was conducted by making use of this sensory method. The effective range and the accuracy of this method are discussed based on the data of the above measurement. It is shown that, if a suitable control (temporary standard) sample is chosen, the instrumental values of bending rigidity, thickness and compressibility of worsted fabrics can be estimated by this sensory method with an error of around 20 per cent. The sensory measurement of main mechanical properties of knitted fabrics is now being conducted. Very good results have been obtained so far on these points. Project aims and objectives (1) To develop handometry for fabrics by sensory method. (2) To investigate the effectiveness of sensory measurement of fabric mechanical properties. Academic deliverables Refer to the publications.
Publications Alimaa, D., Matsuo, T., Nakajima, M. and Takahashi, M. (1997), Proceedings of the 25th Textile Research Symposium, Mt Fuji, Japan. Matsuo, T., Harada, T., Saito, M. and Tsutsumi, A. (1995), Journal of Textile Machinery Society, Vol. 48, T244.
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Kyoto, Japan Kyoto Institute of Technology, Faculty of Textile Science, Matsugasaki Sakyo-ku, Kyoto, 606 Japan Tel: (075) 724 7846; Fax: (075) 724 7800 T. Matsuo and Ryuichi Akiyama, Department of Polymer Science and Engineering Research staff: Fumitaka Okamoto
Surface mechanical properties of fabrics in terms of hand: part I - Shingosen fabrics Other partners: Academic M. Kinoshita
Project started: April 1993 Keywords: Fabric, Woven fabrics .
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Research register
Industrial None S. Mukhopadhyay K. Izumi Project ends: To be continued
A measurement method for surface mechanical properties (especially frictional properties) of fabrics in the relation with their surface hands has been developed. The effects of the friction probe form, probe velocity, probe weight and the selection of suitable parameters representative of frictional properties are investigated. The relationships between surface hand and surface mechanical properties for Shingosen fabrics have been clarified, in comparison with silk-like fabrics and silk fabrics. An attempt is also made to simulate frictional properties by certain theoretical structure models of woven fabrics.
Project aims and objectives (1) To develop a measuring method for surface mechanical properties (especially frictional properties) of fabrics.
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(2) To find the features of these properties and the relationships between hand and these properties. (3) To simulate frictional properties theoretically on the basis of fabric structure. (4) To analyze Shingosen fabrics from the viewpoint of (2). Academic deliverables Refer to the publications. Publications Akiyama, R. et al. (1995), Journal of Textile Machinery Society, Vol. 48, T153. Kinoshita, M. et al. (1997), Journal of Textile Machinery Society, Vol. 50, T187.
Kyoto, Japan Kyoto Institute of Technology, Faculty of Textile Science, Matsugasaki Sakyo-ku, Kyoto, 606 Japan Tel: (075) 724 7846; Fax: (075) 724 7800 K. Kawabe and T. Matsuo, Department of Polymer Science and Engineering
Tow opening of reinforcing fibre and its application for thermoplastic composites Other partners: Academic Industrial None S. Tomoda Project started: June 1994 Project ends: to be continued Keywords: Fibre, Pneumatics, Thermoplastics Impregnation of matrix resin into fibre is further facilitated by using opened tow rather than compacted tow. A new processing system for spreading tow which is composed of plural rolls and a pneumatic device was introduced. Preliminary opening is conducted by threading it on plural fixed rolls under a suitable initial tension. Transverse air of suitable flow velocity is then applied to the tow of steadily sagged form. Some experimental results for carbon fibre and glass fibre, and theoretical analysis on these opening mechanisms were presented. The roles of roll part and pneumatic part were also discussed. Thus opened tows have been applied to the impregnation of thermoplastic composites. Significant effect of the tow opening on the facilitation of matrix impregnation has been proved.
Project aims and objectives (1) To develop tow opening of reinforcing fibre with high efficiency and low cost. (2) To analyze the opening mechanism. (3) To apply the tow opening technology to the production of thermoplastic composite prepreg. Academic deliverables Refer to the publications. Industrial deliverables At present, laboratorial scale. Publications Kawabe, K., Matsuo, T. and Tomoda, S. (1997), Proceedings of 42nd International SAMPE, Vol. 42, p. 65. Kawabe, K., Tomoda, S. and Matsuo, T. (1997), Journal of Textile Mac. Soc., Vol. 50, T68.
Leeds, UK Leeds Metropolitan University, Calverley Street, Leeds, LS1 3HE, UK Tel: (0113) 283 2600; Fax: (0113) 283 31, E-mail:
[email protected] Dr A.J. Crispin and Professor G. Taylor Research staff: P. Clay
Genetic algorithm approach to leather nesting Other partners: Academic None
Industrial SATRA (Shoe and Allied Trade, Research Association) R&T Mechatronics Project ended: February 2002
Project started: February 2000 Finance/support: £84,500 Source of support: EPSRC Keywords: Leather, Lay-planning, Nesting, Genetic algorithm, Artificial intelligence
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The research investigates the problem of leather lay-planning using genetic algorithm and other evolutionary methods. It is developing new encoding strategies for mapping shape position and angles evolved by an evolutionary algorithm to non-overlapping configurations. Project aims and objectives . to contribute to the understanding of genetic algorithms as applied to nesting problems particularly with respect to quantifying the issues for efficient and robust performance; . to develop efficient genetic algorithm encoding methods for leather nesting . to evaluate yield and process time performance of the researched algorithms and compare their performance with the current state of the art. Research deliverables (academic and industrial) The main benefit will be to the research community involved in two-dimensional cutting and packing problems in the textile and leather industries. Publications Clay and Crispin (2001) ‘‘Automated lay planning in leather manufacturing’’, National Conference of Manufacturing Research, Cardiff, Wales. Others in progress
Liberec, Czech Republic Technical University of Liberec, Faculty of Textiles, 461 17 Liberec, Ha´lkova 6, Czech Republic Tel: 00420 48 25441/25462 Professor Stanislav Nosek, Department of Weaving Technology (newly renamed Department of Mechanical Technologies in Textiles) Research staff: Ingolf Brotz, Petr Tumajer, Ales˘ Cvrkal and Jaroslava Richterova´
Research of shocks (impacts) and vibrations excited by technological processes in weaving and other textile machines Other partners: Academic Industrial None None Project started: 1998 Project ends: Finance/support: Kc˘1,900,000 (estimated)
Source of support: Applied with the Grant Agency of the Czech Republic (GACR) (or will be worked out as an internal project of TU Liberec) Keywords: Textiles, Weaving Many textile technological processes, especially the weaving process, produce during each working cycle a row of force impulses which affect the processed textile material as well as the machine. The impact of these impulses causes the propagation of delayed deformation of both media – textile material and machine parts – so that the deformation can return to the source of impulse through several paths. The result is that the next impulse changes with respect to the previous one and the technological process may become unstable or steadied in a different regime to that originally set on the producing system, etc. That can affect the quality of the produced good. At the same time, the excited shocks and vibrations in the system material – working machine – can be emitted in the air or into the floor as noise or vibrations on a wide band of frequencies and can affect the workers as well as the environment and the building. The problems of arising propagation and damping of technologically affected impulses and vibrations will be studied first on the process of fabric forming of the loom as the effect of beat-up, of shedding, back rest motion, functioning of fabric take-up and warp let-off devices. Later, the research should be widened to further textile processes – winding, warping, etc. Project aims and objectives The aim of the research is mainly to explain why and how the produced goods on textile machines often differ from the structure and quality of the goods originally (theoretically) set on the machine. One possible reason may be the deviated motions of textile material and machine parts caused by impulses and vibrations in these compliable and massive media, which impulses result from the technological process itself. The research will start with the weaving machines. Academic deliverables A new theoretical view on the stability of technological processes as processes of propagation and returning (feedback) of impulses and vibrations in compliable textile material and machine parts in textile technologies. The research will also be explored as the source of problems for training of PhD students. Industrial deliverables Results will be applied in textile machines design. Results concerning the propagation of vibrations into the air and into the floor will be used to research the protection of persons as well as buildings against damage by noise and vibrations.
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Publications Hanzl, J. (1995), ‘‘The behavior of the back rest on the loom’’, Poster and Book of Transactions, International Conference of Young Textile Science, TU Liberec. Nosek, S. (1994a), ‘‘The dynamics of fabric forming at high weaving rates’’, Industrial Journal of Fibre & Textile Research, Vol. 19 No. 3. Nosek, S. (1994b), ‘‘The dynamics of fabric forming on the loom and problems of weavability at high weaving rates’’, World Textile Conference, Huddersfield. Nosek, S. (1995a), ‘‘Dynamics and stability of beat-up’’, Fibers & Textiles in Eastern Europe, Vol. 1 No. 1, Lodz. Nosek, S. (1995b), ‘‘Feedback phenomena in textile processes’’, International Conference of Young Textile Science, TU Liberec. Nosek, S. (1995c), ‘‘Mechanics and rise of stop marks and structural bars in fabrics’’, Poster and Book of Transactions, IMTEX ’95, Lodz, Polsko. Tumajer, P. (1995), ‘‘Dynamics of start of a weaving loom and the possible rise of transition marks’’, Poster and Book of Transactions, International Conference of Young Textile Science, TU Liberec.
Liberec, Czech Republic Technical University of Liberec, Halkova 6, 461 17 Liberec, Czech Republic Tel: +420 48 5353498; E-mail:
[email protected] Zdene˘k Ku˚s, Head of Department, Department of Clothing Research staff: Jir˘´ı Militky´, Otakar Kunz, Antonı´n Havelka, Dagmar Ruz˘ic˘kova´, Vladimı´r Bajzı´k, Jana Zouharova´, Andrea Halasova´, Viera Glombı´kova´, Blaz˘ena Musilova´, Petra Koma´rkova´, Jaroslav Beran, Josef Olehla, Miroslav Brzezina
Organoleptic properties of three-dimensional textile objects Other partners: Academic Industrial Other departments of the university Project started: 1 January 1999 Project ends: 31 December 2004 Finance/support: £70,000 Source of support: Ministry of Education, Technical University of Liberec Keywords: Fabric properties, Comfort, Handle, Thermal The research will be performed in the following areas:
Surface properties of textile formations, non-linear deformations of fabric . Computer simulation of impact surface parameters of the planispheric textile fabric to their chosen macroscopic properties. This is made with the aim of predicting and optimising these properties. Provide evolution for new measurement methods in this area. . Computer simulation of non-linear deformation of the planispheric textile fabric with ballast, for example, by means methods of final elements. Physiological properties of comfort textile formations, fabric handle . Development of new methods for evaluation of physiology comfort and fabric handle. The following application progressive computers method. For example, the neural networks or the artificial intelligence for comparing objective new parameters with empirical find out values. Thermal properties of textiles sandwich materials . Development of new devices for measurements of thermal properties of textile composites and textiles sandwich materials, with special regard to these materials applied in extreme conditions. . Objectification of the property evaluation of textile materials from the point of view of comfort and hygienic properties. Project aims and objectives New methods of measurement, computer simulation of fabric deformation, etc. Publications Halasova, A. and Glombı´kova´, V. (2000), ‘‘Problem of simulation working breakdown apparel production in program accessories witness’’, Proceedings of Textile Science 2000, Liberec, Czech Republic, 12-16 June, ISBN 80-7083-409-9, p. 375. Hes, L., Li, Y. and Kus, Z. (1999), Ochranna´ textilie proti sa´lavemu teplu a ochranny´ oblek z te´to textilie, Czech Republic Patent PV1673-99. Kus, Z. (1999), ‘‘Investigation of seam pucker with help of image analysis’’, Proceedings of the 5th Asian Textile in the 21st Century Conference, Kyoto, Japan, p. 333. Kus, Z. and Koma´rkova´, P. (2000), ‘‘Computer simulation of apparel production’’, Vla´kna a Textil, Vol. 7 No. 2, ISSN 1335-0617, pp. 113-16. Kus, Z., Glombı´kova´, V. and Brada´cova´, H. (2000), ‘‘Application of image analysis and neural network for the evaluation of seam pucker’’, Proceedings of Textile Science 2000, Liberec, Czech Republic, 12-16 June, ISBN 80-7083-409-9, pp. 391-3. Trung, N.C. and Kus, Z. (1999), ‘‘Computer simulation of sewing needle heating’’, Progress in Simulation, Modeling, Analysis and Synthesis of Modern Electrical and Electronic Devices and Systems, World Scientific and Engineering Society Press, Athens, Greece, ISBN 960-8052-08-4, pp. 166-70.
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Louisiana, USA School of Human Ecology, Louisiana State University, LSU, Baton Rouge, LA 70803-4300 Tel: (225)578-2407; Fax: (225)578-2697; E-mail:
[email protected] Yan Chen and Jianhua Chen, LSU School of Human Ecology, LSU Department of Computer Sciences Teresa Summers, Jackie Robeck, Al Steward, and Ramesh Kolluru
Online fabric sourcing database with data mining and intelligent search Other partners: Academic Industrial University of Louisiana-Lafayette None Project started: 1 June 2001 Project ends: 30 June 2004 Finance/support: $119,822 Source of support: LA Board of Regents Keywords: Fabric properties, Fabric sourcing, Tailorability, Drapability, Online database With rapid development of Internet for business applications and e-commerce, textile manufacturers, garment makers, and clothing retailers are eager to go online for fashion tracking and material sourcing. The goal of this project is to establish an online intelligent database that will help the industry users to locate desired fabrics that match fashion trends in color, drape, and style; to narrow fabric selections to fabrics possessing good physical properties that insure high garment quality; to find better-buy fabrics; and to locate fabric manufacturers and determine earliest shipping date. Major objectives include: (1) construction of a database server using a PC and the Oracle software; (2) establishment of a dynamic database composed of fabric structural parameters, mechanical properties, drape images, tailorability, and manufacturers’ contacting information; (3) development of an intelligent search engine allowing clients to scour the database for their own priorities; and (4) investigation of new search patterns that relate client’s fashion requirements to fabric properties using the new data mining techniques of fuzzy clustering and decision tree approach. The new database will merge an existing database created by faculty at the ApparelComputer Integrated Manufacturing Center (ACIM) at UL Lafayette. This existing database is providing information of the Louisiana Textile, Apparel, and Retail Consortium that aids the state economic development. With accessibility to this database, the new data resources, new search engine, and
new search patterns developed in this research can be applied to this existing database. This will greatly enhance its functionality and help form a united textile and clothing sourcing database in the state and US. Research deliverables (academic and industrial) Online intelligent database and web service. Publications Jianhua Chen, Yan Chen, Bin Zhang and Ayse Gider (2002), ‘‘Fuzzy linear clustering for fabric selection from on-line database’’, 2002 Annual Meeting of the North American Fuzzy Information Processing Society Proceedings, IEEE System, Man and Cybernetics Society, New Orleans, LA, pp. 518-22.
Manchester, UK Department of Clothing Design and Technology, Manchester Metropolitan University, Old Hall Lane, Manchester M14 6HR, UK Tel: 01612472632; Fax: 01612476329; E-mail:
[email protected] Dr. J.E. Ruckman, Mrs. H.D. Rowe Research staff: Dr. A. Popp
Quality control in fashion/textiles supply chains Other partners: Academic None Project started: May 1998
Industrial None Project ended: Project completed on May 2001
Finance/support: £50,000 Source of support: Faculty Research Fund Keywords: Clothing, Quality control, Supply chains, Testing The internationalisation of the fashion/textile supply chain is an ongoing process. This development is often characterised as being primarily cost driven. However, there are many non-cost dimensions of supply chain internationalisation which remain relatively unexplored. This project seeks to explore the impact of international sourcing on the issue of textile and garment quality. The aim of the project is to identify the place and role of quality within the fashion supply chain, to assess whether this role and position is changing as internationalisation takes place and to evaluate intra- and inter-firm handling of testing and quality issues.
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An initial literature review has been conducted and a theoretical perspective established. First, the internationalisation of the industry is situated within an industry life-cycle and comparative competitive advantage perspective that seeks to illuminate the strategic attributes of internationalisation. Second, intraand inter-firm relationships will be approached from an institutional perspective. Thus the study poses questions such as: what is the institutional context within which internationalisation is set? How are issues of governance and coordination handled? Who sets the rules and regulations of testing? A pilot survey of UK retailers and manufacturers, conducted via face-to-face interviews, is currently being undertaken in preparation for a larger questionnaire survey. The third stage of the project will involve devising and conducting a performance test targeted at participating firms and utilising prepared fabric samples. The project will yield qualitative and quantitative data, allowing both the characteristics and performance of varied supply chain configurations to be assessed. Publications Two papers have been presented at conferences, including the 80th Textile Institute World Conference, and four papers have been published in journals.
Manchester, UK Department of Clothing Design and Technology, Manchester Metropolitan University, Old Hall Lane, Manchester M14 6HR, UK Tel: 01612472632; Fax: 01612476329 E-mail:
[email protected] Dr. J.E. Ruckman Research staff: Dr. A.G. Oh
Water vapour transfer through layered clothing systems Other partners: Academic Industrial None None Project started: October 1999 Project ended: September 2002 Finance/support: N/A Keywords: Clothing systems, Microclimate, Water vapour transfer
The transfer of water from the human body through clothing to the outside atmosphere is an important factor in human comfort. Many researchers emphasised the importance of studying water vapour through textile fabrics, layered fabrics and clothing systems. However, most studies were carried out under steady-state conditions, with the result that many factors that play an important part in the comfort of the weaver in different conditions were largely ignored. There is also the limitation of instrumental measurements of moisture transfer to simulate the actual comfort performance of clothing and actual temperature and humidity changes in the microclimates. In wear, these textiles and fabrics form part of a layered clothing system. The aims of this research are therefore to establish a suitable technique for the measurement of water vapour transfer through layered clothing systems and to investigate the ways in which the mechanism of water vapour transfer affects the layered clothing systems, and consequently the human body. Publication A paper has been presented at the 6th Asian Textiles Conference held in Hong Kong, August 2001.
Manchester, UK Department of Clothing Design and Technology, Manchester Metropolitan University, Old Hall Lane, Manchester M14 6HR, UK Tel: 01612472632; Fax: 01612476329; E-mail:
[email protected] Dr. J.E. Ruckman, Dr. S.G. Hayes Research staff: Dr. J.H. Cho
Development of a perfusion suit incorporating auxiliary heating and cooling systems Other partners: Academic Industrial None None Project started: January 2000 Project ended: January 2001 Finance/support: £20,000 Source of support: Korea Research Foundation Keywords: Cooling garment, Pre-shaped, Exercise Examining the specific effects of temperature change on muscle function is important for athletes, as a decrease in muscle temperature by 1-2 C has been shown to result in a 10-20 per cent decrease in power output, and therefore affects
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the athletes’ performance in cold environment competition. Increasing muscle temperature has been shown to produce the opposite effect. Examining the specific effects of temperature change on muscle function is also important in understanding individuals’ physiological response to thermal stress, particularly for fire-fighters or cold-store workers who are exposed to extreme environmental temperatures. Traditional studies examining the effects of temperature perturbation on muscle function have commonly employed either water immersion or lowintensity exercise as means of changing muscle temperature. The aim of this research project is to study the feasibility of developing a ‘‘perfusion suit’’ which will be applicable to various needs of an individual for auxiliary heating or cooling. The feasibility study will concentrate first on identifying the most appropriate textile material and the method by which the auxiliary heating and cooling system is incorporated into the identified textile material. The pilot garment will then be constructed, probably based in the ‘‘chaps’’ design with pockets in the areas of major muscle groups. Various sets of experiments will then be conducted to evaluate empirically the effectiveness of this pilot garment by monitoring changes of human muscle temperature when part of the human body is covered with the basic garment incorporating a basic auxiliary heating and cooling system. Publication A paper has been published in the IJSCT.
Manchester, UK Department of Clothing Design and Technology, Manchester Metropolitan University, Old Hall Lane, Manchester M14 6HR, UK Tel: 01612472632; Fax: 01612476329; E-mail:
[email protected] Dr. J.E. Ruckman, Prof. M.K. Song
Heat and water vapour transfer through high performance clothing systems Other partners: Academic Industrial None None Project started: April 2002 Project ends: March 2004 Finance/support: £15,000 Source of support: British Council Keywords: High-tech fabrics, Layered clothing system, Mass transfer
When technical fabrics are used in a clothing system it is to be expected that the performance of a fabric itself is not the only factor which contributes to thermophysiological comfort. In real life technical fabrics that are developed to suit outdoor activities are rarely worn on their own, but are incorporated into a layered clothing system, especially that incorporating a waterproof breathable fabric as an outer shell. For this reason, the characteristics and properties originally developed for specific end-uses (and evaluated using testing methods based upon Fick’s Law) may not be as decisive as originally anticipated. The aims of this project are to investigate the heat and water vapour transfer through high performance clothing systems and to identify the optimum combination of technical fabrics for each layer of a high performance clothing system.
Manchester, UK Manchester Metropolitan University, Department of Clothing Design and Technology, Old Hall Lane, Manchester M14 6HR, UK Tel: (0161) 247 2632; Fax: (0161) 247 6329; E-mail:
[email protected] Dr J.E. Ruckman and Professor R. Murray, Department of Clothing Design and Technology Research staff: Mr J. Qu
Predictive model for determining the onset of internal condensation in performance clothing systems Other partners: Academic Industrial None None Project started: October 1999 Project ended: September 2002 Finance/support: £37,500 Source of support: University Research Fund Keywords: Clothing system, Condensation, Predictive model, Testing method, Water vapour transfer Internal condensation in fabrics is a key factor in reducing the effectiveness of water vapour transfer and hence comfort in high performance clothing systems. A working design for a device to accurately measure and vary temperature and relative humidity on either side of a fabric sample and simulate conditions similar to those encountered under extreme environments has been completed and a prototype machine built.
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The research project will explore the range of the device’s applicability, reliability and validity and refine the prototype machine via a series of experiments with both standard and high performance clothing materials. Confirmation of performance will be followed by the establishment of a methodology to achieve reproducibility of experimental results. Research will then lead to the construction of a predictive model for internal condensation, its effect on water vapour transfer and comfort of the wearer for performance clothing systems. Together with the objective measurement and theoretical consideration of water vapour transfer, a wearer trial utilising the application of sensory assessment techniques on clothing systems will also be performed. Publications Two papers have been presented at conferences, including the World Congress: High Performance Textiles held in Bolton, July 2001.
Manchester, UK Manchester Metropolitan University, All Saints Building, All Saints, Manchester M15 6BH, UK Tel: (0161) 247 2776; Fax: (0161) 247 6329; E-mail:
[email protected] Dr S.G. Hayes, Jackie Jones, Department of Clothing Design and Technology Research staff: Wendy Bailey
The development of an evaluation system for ergonomic clothing comfort Other partners: Academic Industrial None None Project started: 1 October 1999 Project ended: 30 September 2002 Finance/support: £30,000 Source of support: Manchester Metropolitan University Keywords: Ergonomic, Comfort, Clothing, Functional, Evaluation The broad aim of this project is to develop a subjective evaluation system for the ergonomic comfort of functional clothing. Clothing comfort consists of three elements: thermophysiological, ergonomic, and sensorial. This work will complement the existing understanding of thermophysiological comfort and further extend the ability of organisations to develop innovative clothing with
high-performance applications. Garments designed at different levels are being compared with respect to pattern engineering, garment engineering, and seam engineering aspects which can help or hinder movement during a specific activity. A subjective assessment system will provide data to relate wearer comfort to design features. It is envisaged that an extension to this work will include the development of an objective evaluation methodology. Project aims and objectives . To evaluate clothing comfort, mobility and movement using subjective measures. . To establish a relationship between a range of garment designs and ergonomic clothing comfort. . To develop a subjective evaluation system for ergonomic clothing comfort. Research deliverables (academic and industrial) . A subjective evaluation system to be adopted by industry. . Increased understanding of human/garment interaction. . A system of communication to best describe garment comfort.
Maribor, Slovenia Faculty of Mechanical Engineering, University of Maribor, Smetanova ulica 17, SI-2000 Maribor, Slovenia Tel: +386 2 220-7960; Fax: +386 2 220-7990; E-mail:
[email protected] Associate Prof. Dr Sc. Jelka Gersˇak, Department for Textiles, Institute of Textile and Garment Manufacture Processes Research staff: Research Unit Clothing Engineering, Research Unit Textile Technology
Clothing engineering and materials Other partners: Academic Industrial None None Project started: 1999 Project ends: 2003 Finance/support: 15.052.943,00 SIT or 65.840,62 ECU for 2001 Source of support: Ministry of Education, Science and Sport Keywords: Clothing, Fabric, Mechanical properties, Behaviour, Prediction
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The research programme was based on three main activities: basic research on fabric mechanics regarding the non-linear mechanical fabric properties at low stresses and search for model of a fabric as shell; study of response of a fabric against acting stresses in garment manufacturing processes; and study of a behaviour between fabric’s mechanical properties and quality of a produced garment. In frame of the first group of activities, the research was focused on study of a fabric as shell. We have studied the fabric behaviour from the point of view of continuum mechanics. This work resulted in mechanical model of a fabric that was described with rheological coefficients, i.e. elastic and shear module and Poisson’s number. Furthermore, the fabric was modelled using the finite elements method and programme package ABAQUS. The second group of activities referred to the study of fabric response to acting stresses in garment manufacture processes and contained: (1) Study of relationship between tensional stresses and deformations of fabrics. Based on the study of the relationship between the parameters of mechanical properties of analysed fabrics and their response to acting tensional stresses, resp. resulted deformation, it was stated that deformation degree and relaxation time directly depended on mechanical properties of fabrics, acting load and length of the fabric layers. (2) Study of fabric behavior in garment manufacturing processes, which was focused above all on fabric response to acting stresses during cutting, fusing and finishing. The research resulted in: . definition of relationships between fabric mechanical properties and their behaviour in different garment manufacturing processes, . definition of potential problematic spots in manufacturing processes and limit values of particular mechanical properties of fabrics, . set-up of a model ‘‘NAPOVED1.1DZ’’ for prediction of fabric behaviour in garment manufacturing processes. The model was designed in Microsoft Access in such a manner that all respective data, i.e. parameters of mechanical properties were joined together using appropriate relation functions. Study of relationship between the mechanical properties of fabrics and quality of produced garments was carried out in the frame of the third group of research activities. The aim was to design the model for qualitative prediction of garment appearance quality using the principles of objective evaluation of the quality level of garment appearance and comparable estimation of garment suit.
Project aims and objectives Project aims are: definition of principles of fabric behaviour in garment manufacturing processes regarding the non-linear mechanical properties of a fabric, set-up of a model for prediction of fabric behaviour in garment manufacturing processes, definition of relationships between fabric mechanical properties and quality of a produced garment, design of a model for prediction of garment appearance and set-up of a model of fabric as shell. Research deliverables (academic and industrial) Achieved knowledge in a field of fabric mechanics and fabric response to acting stresses, resp. fabric behaviour in garment manufacturing processes, as well as defined limit/critical values of fabric mechanical properties represent an important contribution of the research from the scientific as well as applied point of view. Designed model for prediction of fabric behaviour in garment manufacture processes, ‘‘NAPOVED1.1DZ’’, which comprehends achieved cognitions of basic research on fabric mechanics, and designed knowledge base in Microsoft Access, can be also stated as important applied results of the research. The other important applied achievement is designed simulation of a fabric with the help of a programme package ABAQUS. Fabric model is designed on the basis of numeric modelling as a starting point for study of fabric draping and formability. Furthermore, using appropriate programming tools it will be possible to carry out the simulation of a garment suit. Publications Gersˇak, J. (2002a), ‘‘Development of the system for qualitative prediction of garments appearance quality’’, International Journal of Clothing Science and Technology, Vol. 14 No. 3/4, pp. 169-80. Gersˇak, J. (2002b), ‘‘A system for prediction of garment appearance’’, Textile Asia, Vol. 33 No.4, pp. 31-4. Gersˇak, J. and Zavec, D. (2000), ‘‘Creating a knowledge basis for investigating fabric behaviour in garment manufacturing processes’’, Annals of DAAAM for 2000 and Proceedings of the 11th International DAAAM Symposium Intelligent Manufacturing and Automation: Man-MachineNature, DAAAM International, Vienna, pp. 155-6. Jevsˇnik, S. and Gersˇak, J. (2001), ‘‘Use of a knowledge base for studying the correlation between the constructional parameters of fabrics and properties of a fused panel’’, International Journal of Clothing Science and Technology, Vol. 13 No. 3/4, pp. 186-97. Zavec, D. and Gersˇak, J. (2001a), ‘‘Modular development of prediction knowledge base’’, Annals of DAAAM for 2001 and Proceedings of the 12th International DAAAM Symposium Intelligent Manufacturing and Automation: Focus on Precision Engineering, DAAAM International, Vienna, pp. 519-20. Zavec, D. and Gersˇak, J. (2001b), ‘‘Prediction of fabric behavior as an input information for garment manufacturing process (Napoved obnasˇanja tkanin kot vhodna informacija za proces izdelave oblacˇil)’’, Tekstilec, Vol. 44 No. 9/10, pp. 271-9.
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Maribor, Slovenia Faculty of Mechanical Engineering, University of Maribor, Smetanova ulica 17, SI-2000 Maribor, Slovenia Tel: +386 2 220-7960; Fax: +386 2 220-7990; E-mail:
[email protected] Associate Prof. Dr. Sc. Jelka Gersˇak, Department for Textiles, Institute of Textile and Garment Manufacture Processes Research staff: Research Unit Clothing Engineering, Research Unit TEXTA tovarna sukancev in trakov d.o.o.
The investigation and development of high quality extended PES filament threads Other partners: Academic None
Industrial TSP d.d. TOVARNA SUKANCEV IN TRAKOV Project started: April 2001 Project ended: September 2002 Finance/support: 6.313.460,00 SIT or 27.614,67 ECU for 2001 Source of support: Ministry of the Economy Keywords: Sewing thread, PES filament, Hot extension The research is based on six stages. In the first one, an extensive research on functional properties and specific requirements for high-quality PES filament threads was carried out. It resulted in a document called ‘‘Technical regulations for 100 per cent PES filament threads’’. The second stage run parallel. Research on specific requirements of filament yarns in order to achieve high quality threads was carried out. Furthermore, finishing methods and techniques were carried out. The main aim was the study of constructional parameters of PES filament threads regarding their strength, extensibility, and dimension stability, as well as optimisation possibilities of these parameters. Achieved results of the research on relationship between thread twist and breaking tenacity of a filament thread showed significant differences when compared to threads, produced from spun yarns. Extensive research in the area of hot extension of PES filament thread was carried out in the frame of the third stage of the project. The main goal was to improve the mechanical properties of existing threads and study of the influence of a new drafting technique in hot medium on mechanical properties of PES filament threads. The analysis of achieved mechanical properties after drafting has shown that these properties were dependent on constructional parameters of filament yarn and on following drafting parameters: temperature, processing
speed, acting tensional forces and compression forces. Drafting parameters were determined in the fourth stage of the research. Beside process FMEA, also the research on influence of hot extension on change of constructional parameters and physical/mechanical properties of analysed threads, as well as isolated fibres/filament yarns was carried out. The analysis of achieved results of the research on mechanical properties of PES filament threads after hot extension has shown that this process influenced the change of certain mechanical properties of threads, as well as isolated fibres/filament yarns. Project aims and objectives The main goals of the project were to study the properties and specific requirements for PES filament threads according to the needs of the automotive industry, to study the behaviour of the thread in hot medium and introduction of new technology for hot extension of a thread into finishing process with the aim to improve mechanical properties of existing PES filament threads, resp. to develop a new product with higher tenacity and suitable extensibility. Research deliverables (academic and industrial) Important contribution regarding the scientific as well as applied point of view can be seen as new cognitions of the influence of thread’s constructional parameters and hot extension on change of viscoelastic properties of the thread and twisted filament yarns. Achieved cognitions can be considered as starting points for projecting the sewability of filament threads and their applied properties. Also the determination of optimal parameters of thread’s hot extension according to the planned mechanical properties and development of a new, highquality product based on the stabilised production process will be one of more important contribution of the research. Publications None
Maribor, Slovenia University of Maribor, Faculty of Mechanical Engineering, Smetanova 17, 2000 Maribor, Slovenia Tel: +386 62 220-7960; Fax: +386 62 220-7990; E-mail:
[email protected] Associate Prof. Dr Sc. Jelka Gers˘ak, Institute of Textile and Garment Manufacture Processes, Clothing Engineering Laboratory Research staff: Daniela Zabec, BSc
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Study of the influence of interaction of heat, moisture and pressure on textile material–garment Other partners: Academic None
Industrial MURA European Fashion Design Murska Sobota Project started: June 1998 Project ended: June 2001 Finance/support: SIT4,390,605 or ECU23,230 for 1998 Source of support: Ministry of Science and Technology of Republic of Slovenia: SIT3,073,424 for 1998, Industrial partner: SIT1,317,181 for 1998 Keywords: Clothing, Iron, Transformation The aim of the project is investigation of the interaction of the heat, moisture and pressure on a textiles material and its behavior during ironing process. Ironing of textile materials, respectively clothes, represents a very complex area, because the textile material is in defined time being transformed or changed with help of heat, moisture or vapour and pressure and finally chemical or physically fixed, so that initial form is changed to the proper and relatively stable end form of the material or cloth. There are three material dependent physical-chemical processes; polyester is thermo-plastically transformed and fixed, cotton is performed and fixed in absorption process, while the wool is transformed chemical-physically. The ironing parameters have to be in agreement with these three different transforming mechanisms of the material. For the ironing quality not only is the interaction of the influence of the heat, moisture and pressure important, but also their influence on transforming and dimensional changes in the textile material. The material’s behavior during ironing also depends on its mechanical and physical properties. The behaviour of shell fabric during ironing process is very difficult to predict, although the mechanical, heat and chemical processes are known. Particularly problematical are areas where the fabric is fused with interlining and on the seam area. The knowledge of material properties and their behaviour during the ironing is to be regarded as the basis for the planning of ironing parameters. Project aims and objectives are: . To study and investigate the influence of interaction of heat, moisture and pressure on textile material – garment; study of the behaviour of garment during ironing; . To study the resulting interactions on a change of mechanical and physical properties of the textile material, i.e. above all the relaxation shrinkage and wet extension;
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To study and investigate the behaviour of the base material and interlining as a joint composite in produced garment during the ironing as well as to investigate the influence of heat, moisture and tension on seam as a joint element of a garment, or interaction fabric – seam, respectively; and To define the optimal ironing processing parameters, i.e. the effect of heat, moisture and pressure on the basis of mechanical and physical properties of fabrics and their behaviour during the ironing process.
Academic deliverables The realisation of the project will result in definition of the interaction of the influence of heat, moisture and pressure on textile surface and thus connected change of mechanical and physical properties of a textile material that is built in a garment. Furthermore, new cognitions regarding the behaviour of textile materials during the ironing process will be achieved. An important achievement that will contribute to the application of results of the project will be the knowledge about the ironing mechanism and deformation model of a textile material, fabric’s surface and seam as garment’s joint element and relationship between these elements: fabric – joint composite - seam. Industrial deliverables The project is conceived in such a way that achieved results of the research will enable optimisation of mechanical and physical properties of a fabric from the point of view of their behavior during the ironing process. The designed deformation model of a fabric will also enable the optimisation of processing parameters for ironing of garments. Publication Vnuk, R. and Gers˘ak, J. (1998), ‘‘Influence of the mechanical and physical properties of a fabric on pressing quality’’ (Vpliv mehanskih in fizikalnih lastnosti tkanine na kakovost likanja), Proceedings of the IV Symposium Clothing Engineering ’98, Faculty of Mechanical Engineering, Maribor, pp. 90-6.
Minho, Portugal The University of Minho, Centre for Textile Science & Technology, Campus de Azure´m, 4800 Guimara˜es, Portugal Tel: +351 53 510280; Fax: +351 53 510293 Maria Jose´ Arau´jo Marques, Department of Textile Engineering Research staff: Maria Elisabete Cabec¸o Silva, Dominique Adolphe, Laurence Schacher and Anto´nio Alberto Cabec¸o Silva
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Contribution to the parameter setting study for disposable textiles used in the health-care sector Other partners: Academic ENSITM – Ecole Nationale
Industrial Fapomed S.A. ITN – Instituto Tecnolo´gico e Nuclea Project started: October 1998 Project ended: September 2002 Source of support: Conve´nio ICCTI/Embaixada de Franc¸a Keywords: Non-active medical devices (medical textiles), Non-wovens, Protective clothing, Technical textiles The Portuguese textile industry embraces all sectors, from the production of raw materials and spinning up to the garment industry, mostly conventional textiles, like home textiles and classic garments. The competition of other countries in East Europe, Asia, North Africa and other European countries, among them Greece and Turkey, is growing in these industries. Because of that we have to gain competitive advantages and consolidate new markets, namely in the technical textile sector and specifically in the health-care and hygiene market. It is essential that we conquer sectors in which it is possible to demonstrate our gain in quality, know-how and flexibility and the interest in producing a major diversification of innovative products to permit penetration in new markets. In the area of technical textiles, which is actually one of the three major fields of the textile industry, the area of protective fabrics is growing fast, because of the appearance of new fibres, processing and fabrication technologies. An important and growing part of the textile industry is the medical and related health-care and hygiene sectors. The extent of the growth is due to the constant improvements and innovations in both textile technology and medical procedures. Also, the range of products available is vast, but typically the use is either in the operating theatre or on hospital ward for the hygiene, care and safety of staff and patients. Since 70 per cent of these products are disposables from non-wovens, the research design and development must be a priority in this field. The manufacturers of these products used in the operation room present frequently the study of the properties from the material used before sterilisation, without knowing the changes which can appear after the sterilisation, namely in the comfort and barrier properties.
Project aims and objectives This project will treat the surgical gowns – disposables used as medical devices in the health-care facilities – and has the following objectives: . study the properties of surgical gowns – disposables, before and after the submission to several low temperatures sterilisation methods; . study the influence of the sterilisation doses over the properties, to guarantee a maximum safety limit for surgical gowns; . study the influence of ageing through artificial ageing of the surgical gowns by means of elevated temperature with air; . study the different joining methods in the manufacturing of surgical gowns disposables and the possible changes after sterilisation; and finally . compare and quantify the influence of each sterilisation method over the used materials and indicate the most adequate sterilisation methods for each studied type of gown. Publications Arau´jo Marques, M.J. (1995), ‘‘A importaˆncia dos materiais de protecc¸a˜o no aˆmbito da indu´stria teˆxtil’’, Semina´rio EUROTEX: Texteis Te´cnicos – Um Sector em Expansa˜o, Universidade do Minho, Guimara˜es, Portugal, 10-11 July. Arau´jo Marques, M.J. (1998), ‘‘0 papel da subcomissa˜o 5 – vestua´rio de Protecc¸a˜o’’, Sessa˜o de Esclarecimento sobre Marcac¸a˜o CE no Vestua´rio de Protecc¸a˜o, CITEVE, Famalica˜o, Portugal, 2 July. Arau´jo Marques, M.J. and Cabec¸o Silva, M.E. (1996a), ‘‘The mechanical properties of OR garment and surgical drapes – disposables – in the presence of adhesives used in the manufacturing’’, Conference MEDICAL TEXTILES 96, Bolton Institute, Bolton, 17-18 July (poster). Arau´jo Marques, M.J. and Cabec¸o Silva, M.E. (1996b), ‘‘The properties of non-wovens in the healthcare industry’’, Conference TECNITEX, Turin, Italy, 21-23 November. Arau´jo Marques, M.J. and Cabec¸o Silva, M.E. (1997a), ‘‘Aplicac¸o˜es de teˆxteis hospitalares em Portugal’’, 1 as Jornadas Teˆxteis e do Vestua´rio, Universidade do Minho, Guimara˜es, Portugal, 2-4 April. Arau´jo Marques, M.J. and Cabec¸o Silva, M.E. (1997b), ‘‘Performance requirements of medical textiles – single use materials’’, Advances in Fibre and Textile Sciences and Technology, The Fiber Society Spring Meeting, Mulhouse, France, 21-24 April. Arau´jo Marques, M.J. and Cabec¸o Silva, M.E. (1997c), ‘‘The design of surgical clothing – application in the health-care and hygiene industry’’, Conference TECNITEX, Turin, Italy, 19-21 November. Arau´jo Marques, M.J. and Cabec¸o Silva, M.E. (1998a) ‘‘Propriedades e materiais teˆxteis relevantes nas aplicac¸o˜es me´dico-ciru´rgicas’’, II Jornadas Teˆxteis e do Vestua´rio, Universidade do Minho, Guimara˜es, Portugal, 22-24 April. Arau´jo Marques, M.J. and Cabec¸o Silva, M.E. (1998b), ‘‘Contribution to the definition of properties important for disposable OR garments’’, 4. Dresdner Textiltagung 1998, Technische Universita¨t Dresden, Dresden, Germany, 24-25 June. Arau´jo Marques, M.J. and Cabec¸o Silva, M.E. (1998c), ‘‘Aplicac¸o˜es de Teˆxteis Hospitalares em Portugal’’, XVII Congresso Nacional dos Te´cnicos Teˆxteis, 5a Feira Nacional da Indu´stria Teˆxtil, Casa Grande – Guaruja´, Sa˜o Paulo, Brasil, 9-12 September.
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Arau´jo Marques, M.J. and Cabec¸o Silva, M.E. (1999), ‘‘New materials for medical and surgical applications (non-active medical devices)’’, Materiais 99 Conference, Universidade do Minho, Guimara˜es, Portugal, 21-23 June. Arau´jo Marques, M.J., Cabec¸o Silva, M.E. and Cabec¸o Silva, A.A. (1997), ‘‘Design of medical textiles – application in the health-care industry’’, The Fiber Society Autumn Meeting, Knoxville, USA, 20-22 October (poster). Arau´jo Marques, M.J., Cabec¸o Silva, M.E. and Cabec¸o Silva, A.A. (1998), ‘‘Multivariate analysis in the optimisation and modelling of the quality properties of surgical clothing’’, CESA 98, NabeulHammamet, Tunisia, 1-4 April. Arau´jo Marques, M.J., Cabec¸o Silva, M.E. and Cabec¸o Silva, A.A. (1999), ‘‘Environmental balance of medical textiles - disposables vs. reusables’’, II Confereˆncia Internacional Teˆxtil/Confecc¸a˜o, SENAIICETIQT, Rio de Janeiro, Brasil, 21-23 July.
Newcastle upon Tyne, UK University of Newcastle upon Tyne, Stephenson Building, University of Newcastle, Newcastle Upon Tyne NE1 7RU, UK Tel: 0191-2227145; Fax: 0191-2228600; E-mail:
[email protected] Paul M Taylor, School of Mechanical and Systems Engineering Research staff: Hua Lin
A feasibility study into robotic ironing Other partners: Academic Industrial King’s College London None Project started: 1 August 2002 Project ends: 28 February 2003 Finance/support: £38,742 Source of support: EPSRC Keywords: Garment, Ironing, Robotics This is an adventurous research aiming at investigating a development in applying robotics techniques to one of the most demanding household activities, performing a feasibility study into robotic ironing. Customer market research will be carried out to establish the minimal functional requirements for a range of potential users. Technical requirements will be established for complete and decomposed ironing tasks. A preliminary technology study will then be made, covering the relevant technologies in the UK, Europe, Japan and the USA to establish the state of the art and to determine advances that must be made. These technologies will cover gripping, handling, folding and manipulation, ironing and relevant textile technologies. Potential machinery manufacturers will be approached to bring their perspective into the
study. Gaps in theories and knowledge will be identified and these will be used to determine the further research that must be carried out to provide solutions to the technical problems in a way that should eventually lead to a product acceptable to the consumer. Finally, a consortium will be established which could carry out this research and proposal(s) will be prepared.
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Project aims and objectives . Establish the detailed functionality of robotic ironing devices. . Examine the existing techniques and required disciplines to solve the technical problems. . Determine in detail the research needed to carry out the work, the team to do it and the resource required. . Identify potential industrial collaborators who might provide commercial follow-through. . Draft research proposal(s) to fund the research programme.
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Publications These surveys will be published in appropriate journals, such as the International Journal of Clothing Science and Technology, Journal of Robotic Systems, and at the 11th IFToMM World Congress in Tianjing in 2003, and at the IEEE ICRA in 2003.
Newcastle upon Tyne, UK University of Newcastle upon Tyne, Stephenson Building, The University, Newcastle upon Tyne NE1 7RU Tel: (0191) 222 7145; Fax: (0191) 222 8600 Professor P.M. Taylor, Department of Mechanical, Materials and Manufacturing Engineering Research staff: D. Pollet
Vibration of fabric panels and automated garment assembly Other partners: Academic Industrial None None Project started: 1 October 1992 Project ends: – Keywords: Bending, Environment, Friction, Grippers The primary aim is to understand the way fabrics and garments interact with mechanical devices designed to hold them and move them around and how their behaviors are affected by environmental changes.
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Studies are being undertaken on an analysis of the behavior of fabric during the pinch gripping operation and on how fabric panels move on vibratory surfaces. To complement this, the relevant properties of fabrics are being studied, particularly buckling, bending and friction under zero and low applied normal forces. Friction and bending tests are also being undertaken over a wide range of environmental conditions to see the effects of humidity changes on handling processes. Project aims and objectives The primary aim is to understand the way fabrics and garments interact with mechanical devices designed to hold them and move them around and how these are affected by environmental changes. Academic deliverables Gripping analysis – vibration analysis, new instrumentation, results showing strong links between handling behavior and environmental conditions. Industrial deliverables None yet Publications Taylor, P.M. and Pollet, D.M. (1996), ‘‘Why is automated fabric handling so difficult?’’, 8th International Conference on Advanced Robotics (ICAR 97). Taylor, P.M., Pollet, D.M. and Griesser, M.T. (1994), ‘‘Analysis and design of pinching grippers for the secure handling of fabric panels’’, Proceedings of Euriscon ’94, Vol. 4, Malaga, Spain, 22-26 August, pp. 1847-56.
Ontario, Canada University of Guelph, Ontario, Canada, N1G 2W1 K. Slater, School of Engineering Research staff: various graduate students
Protective clothing design for agricultural uses Other partners: Academic Industrial None None Project starts: April 1999 Project ends: April 2003 Finance/support: Applications under development Source of support: Various groups to be approached Keywords: Agriculture, Protective clothing
The project depends on the ability of textile materials to be incorporated into designs of garments which can resist the ingress of harmful chemicals yet allow the escape of perspiration moisture. Preliminary design considerations have been established, but continuation of the work depends on the successful negotiation of adequate funding, a step which is currently in progress. Project aims and objectives The aim of the project is to develop a clothing system capable of providing agricultural workers with adequate protection from the various chemical and microbiological hazards which they continually encounter in their daily work. Academic deliverables One or more graduate theses. One or more journal articles. Industrial deliverables Protective clothing capable of preventing health deterioration in agricultural workers continually exposed to harmful chemical or microbiological hazards, with the added advantage of being comfortable enough for the workers to accept it without demur. Publications No publications stemming directly from this project have appeared to date, but some of my earlier work (e.g. protective clothing for operating room use) is relevant and has appeared in the past. I have also presented papers dealing with the need for protection of agricultural workers at several recent conferences.
Ontario, Canada University of Guelph, Ontario, Canada, N1G 2W1 K. Slater, School of Engineering Research staff: various graduate students
Protective clothing design for industrial use Other partners: Academic Industrial None None Project starts: April 1999 Project ends: April 2003 Finance/support: Applications under development Source of support: Various groups to be approached Keywords: Clothing, Industrial clothing, Protective clothing Industrial accidents frequently cause injuries which could have been prevented by the use of appropriate protective clothing. Flying projectiles, violent contact
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with machinery, vehicles or the ground, and exposure to harmful chemical or biological materials are encountered regularly in accident reports. This project is intended to build on my previous research in the degradative changes occurring in textiles, and on my comfort research, to match the protective needs of clothing intended to safeguard human beings from the hazardous conditions to which they are exposed. A major need is to ensure that wearers are not likely to discard the protective garments for reasons of physical or mental comfort, so that protection is abandoned. As the work is still in the planning stage, it is not possible to provide any detailed synopsis of its course. Project aims and objectives The aim of the project is to use textile materials, in conjunction with other components, to prevent (or minimise injury from) industrial accidents. Academic deliverables One or more graduate theses. One or more journal articles. Industrial deliverables Protective clothing capable of reducing or eliminating injury, and hence reducing financial costs, arising from workplace accidents. Publications No publications stemming directly from this project have appeared to date, but some of my earlier work relates closely to the needs of this research.
Pendleton, USA Clemson University, 500 Lebanon Road, Pendleton, SC 29670-1957, USA Tel: 864-646-8454; Fax: 864-646-8230 Roy Pargas, Chris Jarvis, Bill Kernodle, Dawn Robertson, Jason Howell, Steve Davis, Clemson Apparel Research
Balanced inventory flow replenishment system Other partners: Academic None
Project started: 16 November 2001
Industrial Parris Island Marine Base EBI Medical Systems, Inc. Stone International, LLC Project ended: 16 November 2002
Finance/support: $500,000 Source of support: Defense Logistics Agency Keywords: Supply chain, Supply network, Flow system, Sewn products This project is developing concepts and software for establishing a balanced flow of products through a supply chain. It extends an earlier system that focused on ordering decisions of a single firm. The new system will recommend ordering, production and distribution actions that benefit the overall supply chain. It is especially well suited for the sewn products industry, wherein the same type product is made in different sizes and colors and the challenge is to maintain the right balance among the different sizes and colors. However, it can also more generally. Primarily it is concerned with maintaining balanced, user-specified levels of inventory in the critical buffers in the supply network. Therefore it measures inventory in days-of-supply rather than number of items. A prototype of this system has been tested successfully for recruit clothing at the U.S. Marine Corps base at Parris Island, South Carolina, and in two non-military commercial applications. Primary benefits to supply network partners are the elimination of stockouts, the reduction of all inventories, and the reduction of manufacturing costs – all at the same time. Project aims and objectives This project will develop software for establishing a balanced flow of products through a supply chain. The software may be used to manage product flow through segments of a supply chain (e.g. lean plant scheduling) or to manage an entire supply chain. Research deliverables (academic and industrial) The main industrial deliverable is innovative concepts and software that support management of a segment of a supply network or an entire network (prototype completed). The main academic deliverable is a report of the balanced flow concepts and of the field experience in applying the software to actual supply chains. Publications Kolluru, R., Meredith, P., Steward, A., Smith, M., Smith, S., Dwivedi, S., Peck, J. and Davis, S. (2001), ‘‘An extended enterprise framework for supply network management’’, International Journal of Agile Manufacturing, Vol. 3 No. 2, pp. 77-102. Pargas, R., Jarvis, C., Davis, J., Peck, J., Kernodle, B. and Luo, W. (2001), ‘‘DSS improves supply chain operations’’, Issues in Information Systems, Vol. II, pp. 357-63. Peck, J., Kolluru, R., Davis, J., Kernodle, B., Jarvis, C., Pargas, R., Steward, A., Smith, M. and Smith, S. (2001), ‘‘Information support for supply network management’’, The International Journal of Agile Manufacturing, Vol. 3 No. 2, pp. 103-8.
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Pendelton, USA Clemson University, 500 Lebanon Road, Pendleton, SC 29670-1957, USA Tel: 864-646-8454; Fax: 864-646-8230; E-mail:
[email protected] Jack Peck, Steve Davis, Chris Jarvis, Nithinant Thammakoranonta, Tyson Wilson, Clemson Apparel Research
New approaches to the tentative order commitment decision in a supply network Other partners Academic Industrial None None Project started: 15 August 2000 Project ended: 31 July 2002 Finance/support: $12,600 Source of support: National Science Foundation (Supplementary) Grant DMI-0075608 Keywords: Ordering, Order commitment, Supply chain management This project investigated the state of the practice and developed and evaluated a new automated protocol for making the tentative order commitment decision. (When a customer seeks to place an order with a firm, that firm must decide whether it can commit to satisfy it.) Making this decision promptly and accurately is important to the efficiency of supply network operations, increases customer satisfaction, and helps suppliers manage their inventories and production more effectively. This investigation of the state of the practice involved a mail survey and interviews of experts. Because there is no evidence that any firms use a formal, automated methodology to make this tentative order commitment decision, it appears our developing a new automated protocol could be a major benefit. Knowledge we gained about the state of the practice helped calibrate the protocol and will help determine how to transfer the new technology to industry. The new protocol is based upon the two-phase commit protocol that guarantees the integrity of a global transaction in distributed computer systems, because the tentative order commitment decision resembles a global transaction in many ways. We evaluated the protocol with reviews by experts in supply chain management and by demonstration through scenarios that it works correctly in any possible supply chain situation or sequence of events. Project aims and objectives The objective of this project was to determine the state of the practice in making the tentative order commitment decision and to develop and
evaluate a new automated protocol for this decision. The new protocol could serve as a basis for software that quickly and accurately makes this decision in a supply network. Research deliverables (academic and industrial) . This project produced a report of the state of the practice in making the tentative order commitment decision. It was based upon analysis of results of a mail survey sent to 1,000 randomly selected members from the Institute for Supply Management, excluding academic members. . Also this project developed an automated protocol for the tentative order commitment decision that will handle a variety of policies for requesting a commitment. Publication Wilson, T., Thammakoranonta, N. and Davis, S. (2001), ‘‘State of the practice in order promising’’, Proceedings of the SE INFORMS Conference, 4-5 October , Myrtle Beach, SC, 2001.
Pendleton, USA Clemson University, 500 Lebanon Road, Pendleton, SC 29670-1957, USA Tel: 864-646-8454; Fax: 864-646-8230 Chris Jarvis, Steve Davis, Bill Kernodle Research staff: Wiboon Masuchun, Sivaram AngannaMuthu
Decision support for balanced inventory flow replenishment system Other partners: Academic None
Industrial Defense Supply Center, Philadelphia Parris Island Marine Base Project started: 15 September 2000 Project ended: 15 September 2001 (renewable annually through 2002) Finance/support: $80,000 (estimated portion of $512,605 contract devoted to this project) Source of support: Defense Logistics Agency Keywords: Clothing ordering and distribution, Supply chain, Decision support system
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This project addresses two problems that are important in effectively managing a supply chain for apparel. First, one must determine efficient choices for the target levels of inventory at various places in the chain and the sizes of transfer batches among different points in the chain. It is desirable to have enough inventory to avoid starving the resources that constitute system-wide constraints, but as little as possible elsewhere. Larger batch sizes help reduce setup costs but reduce system responsiveness. This project will develop a model and a solution method to calculate efficient choices for the inventory levels and transfer batch sizes. Because this problem is so computationally complex the project will probably employ a heuristic search. Second, effective management of a large supply chain requires careful choice of manufacturing resources, considering the trade-off between production cost and speed of response. Most of the production should be done on a high volume, low cost basis. But a certain amount of the available production capacity should be set up for quick response, higher cost production. When actual demand deviates from the forecast, the supply chain needs to be able to respond by changing (part of) the production plan rather quickly. Otherwise stock outages may occur for certain styles or sizes of garments. The question is, what percentage of the production should be rapid response? We will develop models for these problems, determine a solution method, and incorporate that solution in a decision support system. Sponsored by the US military, this project has broad application potential in private industry. Project aims and objectives This project will develop a decision support system for managing an apparel supply chain. The system will help support the following decisions: (1) how to optimize plans for buffer (inventory) and transfer batch sizes throughout the supply chain; and (2) selecting optimum mix of long cycle-time, low-cost manufacturing and quick response, high-cost manufacturing. Research deliverables For the academic community, this project will produce a detailed description of the new models and methods for calculating optimum settings for inventory levels and transfer batch sizes and the optimum percentage of production that should be rapid-response. For the military and industrial community, the project will produce a system capable of supporting decisions by the supply chain manager. Publications None as yet
Pendleton, USA Clemson University, 500 Lebanon Road, Pendleton, SC 29670-1957, USA Tel: 864-646-8454; Fax: 864-646-8230; E-mail:
[email protected] Ramesh Kolluru, Jack Peck, Steve Davis, Stanford Smith, Paul Meredith, Chris Jarvis, Bill Kernodle, Clemson Apparel Research Research staff: Levent Camlibel, Wiboon Masuchun, Nithinant Thammakoranonta, Tyson Wilson
Scalable information flow for the extended business enterprise Other partners: Academic University of Louisiana at Lafayette
Industrial Rutter-Rex Apparel Mfg Co. Milliken Textiles DuPont Performance Textiles, Inc. Performance Designs Defense Supply Center, Philadelphia Project ended: 31 July 2002
Project started: 15 August 2000 Finance/support: $198,573 Source of support: National Science Foundation Grant DMI-0075608 Keywords: Supply network, Enterprise resource planning, Sewn products
This project will develop a model and prototype software for a scalable, extended enterprise resource planning (EERP) system. Based upon an examination of a set of existing supply chains, a general model will be developed to represent a supply network (wherein each firm may have more than one customer and more than one supplier). Standards will be developed for communication interfaces. The prototype software will be designed, developed and tested to determine how well the model supports operation of a small, sewn products supply network with scalability to a complex of military sewn products such as apparel, footwear, and chemical protective suits. This research will lead to new features that are lacking in current enterprise resource planning systems because they focus on supporting internal operations of firms with common ownership or administration. Results of this project will influence the design of future EERP systems to incorporate business-to-business support for groups of cooperating, independently managed organizations – a virtual enterprise that builds competitive advantage through collaboration.
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Project aims and objectives This project will develop a general model of a supply network and prototype software for supply network management. The model will include standards for transactions and for data sharing within the network. The prototype software will be designed, developed and tested to determine how well the model supports operation of a selected small sewn products supply network and how easily it extends to a larger network. Research deliverables (academic and industrial) All these deliverables are completed: . Model of an information system that supports a supply network. . Prototype software based on the model and standards. . Standards for communication interfaces among participating firms. . Report of the model suitability for a sewn products supply chain and model extendibility. Publications Kolluru, R., Meredith, P., Steward, A., Smith, M., Smith, S., Dwivedi, S., Peck, J. and Davis, S. (2001), ‘‘An extended enterprise framework for supply network management’’, International Journal of Agile Manufacturing, Vol. 3 No. 2, pp. 77-102. Luo, W., Davis, J. and Peck, J. (2001), ‘‘Timing control in discrete event simulation’’, IIE Solutions, Vol. 33 No. 5, pp. 32-6 Pargas, R., Jarvis, C., Davis, J., Peck, J., Kernodle, B. and Luo, W. (2001), ‘‘DSS improves supply chain operations’’, Issues in Information Systems, Vol. II, pp. 357-63. Peck, J., Kolluru, R., Davis, J., Kernodle, B., Jarvis, C. and Pargas, R. (2001), ‘‘Information support for supply network management’’, International Journal of Agile Manufacturing, Vol. 3 No. 2, pp. 103-8. Peck, J., Kolluru, R., Davis, J., Meredith, P., Jarvis, C., Smith, S. and Kernodle, B. (2001), ‘‘Scalable information flow for the extended business enterprise’’, International Journal of Clothing Science and Technology, Vol. 12 No. 6, pp. 102-3.
Philadelphia, USA School of Textiles and Materials Technology, Philadelphia University, School House Lane and Henry Avenue, Philadelphia 19144, USA Tel: 215-951-2680; Fax: 215-951-2651; E-mail:
[email protected] Dr. Mohamed Abou-iiana, Textiles Department Research staff: S. Youssef
Knitting and knitting related projects, knitted composites, . . . etc on-line weight and shrinkage control of knits Other partners: Academic Auburn University
Industrial National Textiles, Greensboro, NC, USA Project ends: May 2004
Project started: May 2001 Finance/support: $200,000 Source of support: National Textile Center
An automatic fabric evaluation system has been developed to automatically analyze the knit structures and objectively evaluate fabric properties. Fabric images are captured by CCD camera and preprocessed by Gaussian filtering and histogram equalization. Fabric construction parameters such as courses per inch, wales per inch, fabric cover, weight per unit length are measured and evaluated. The structural changes occurred to the fabric at different levels of fabric relaxation were documented. It has been shown that the system is capable of capturing the structural changes during stress relaxation. This system can be used to on-line control of knit structures during processing by having this image quality acquisition probe determine the spatial characteristics of knitted loop before and after wet treatment. For years knitting has been considered more of an art than a science. Many attempts have been made over the past century to quantify the characteristics of knitted fabrics. The key to unlocking a knitted structure lies within its basic element, the single knitted loop. It has been shown that the length of yarn knitted into a single loop will determine such overall fabric qualities as hand, comfort, weight, extensibility, finished size, cover factor and most importantly fabric dimensional stability. Therefore, to gain control over the characteristics of the fabric performance, the single knitted loop must be controlled to meet certain performance criteria. The problem then arises of how to determine that a knitted loop is of the correct size and shape for a given set of fabric properties. The answer lies in the ability to objectively measure the knitted loop size/shape during processing. Once the loop shape in a fabric is measured, the loops of that size/shape can then be correlated with specific properties of that fabric. With the advent of computers, and more specifically of image analysis and processing, this age old problem of measuring a knitted loop size/shape has been solved [1,2,3,4,5,6,7,8]. Today during fabric processing, a loop can characterize in a matter of seconds with great accuracy instead of the traditional inaccurate techniques of measuring the course spacing or courses per unit length. Computers have not only provided an accurate method for characterizing the loop shape but also a
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means for checking the loop shape to the required shape to achieve certain fabric properties. The knitted structure consists essentially of a yarn bent into the shape of a loop, and this basic element, the loop repeated across the width of the fabric and along its length. The distinctive property of a knitted fabric is its high extensibility in both length and width, which gives it the ability to take up the shape of the wearer and allows it to fit. Attempts to specify the dimensional properties of a knitted fabric in terms of length or width parameter (courses per inch and wales per inch) are subject to high degree of inaccuracy because of its inherent stretch at low loads and poor recovery. Nevertheless, the construction of a fabric is still today frequently described in terms of courses and wales per inch. It is the use of this unreliable and inaccurate parameter for specifying the tightness of a knitted construction, which is directly or indirectly responsible for many of the problems associated with the control of dimensions of knitted structures. This characteristic of a knitted fabric when strained in length or width is due to the fact that the loop shape is easily distorted under low strain conditions and is caused by a change in loop shape without any associated stretching of the yarn forming the loop. In an industrial setting, the techniques of counting the course per inch, wales per inch or unraveling the fabric to determine stitch length are subjected to human error and time consumption. An automatic structure analysis and objective evaluation of knit structures using image analysis techniques will determine the fabric construction parameters and eliminate the subjectivity of the human element.
Pisa, Italy Interdepartimental Research Center ‘‘E. Piaggio’’, Faculty of Engineering, University of Pisa, Via Diotisalvi 2, 56126 Pisa, Italy Tel: ++39-050-553639; Fax: 550650; E-mail:
[email protected] Prof. Danilo De Rossi Research staff: Ing. Alberto Mazzoldi, Ing. Enzo Pasquale Scilingo, Dr. Federico Lorussi, Ing. Alessandro Tognetti, Ing. Federico Carpi
Wearable health care system, WEALTHY Other partners: Academic
Industrial Millior (I)
Institut National des Sciences Centre Suisse d’Electronique et de Appliquees de Lyon (F) Microtechnique (CH) Istituto Scientifico H San Raffele (I) Atkosoft (EL) Centre de Recherches du Service de Messe Frankfurt (D) Sante des Armees (F) Project started: 1 September 2002 Project ends: 28 February 2005 Finance/support: 3.6 10 6 Euro (Total costs) Source of support: EC Keywords: Wearable sensors, Healthcare, Interface V
The WEALTHY activity is planned over 30 months. The specification of the system and the pilot application will be defined as the result of elaboration of user needs and technological requirements. The implementation of software modules will be conducted in parallel in order to assess the integration feasibility among submodules. For this reason the first achievement of the integration is to evaluate the development phase results by establishing some checkpoints in order to make adjustments, if needed, on the ongoing implementation. The following steps need to considered: . A new multifunctional fabric, integrating smart material in form of fiber or yarn, will be realised. Advance textile technology will be used in the component integration also considering comfort and fitting. The wearable garments will be tailored in different shapes. The position and the number of strain gauge sensors and electrodes will be determined in terms of the anatomical location producing the signal and the signal/noise ratio. Alternative sensors will be added, if needed, to increase the number of biophysical variables to be monitored. . The portable part incharge of medical signal acquisition as well as information and communication management will be realised. The implementation of the future UMTS standard will also be examined. . Data processing and representation module will perform the acquisition of physiological parameters, instantiation of patho-physiological model, diagnosis, feedback generation to the patient and to the medical team. Security mechanism will be implemented for controlling the authorisation to access and the manipulation of data and protecting sensitive information. Project aims and objectives The main objective of WEALTHY is to set up a wearable healthcare system that will improve patient or user autonomy and safety. WEALTHY building blocks are:
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cost-effective, non-invasive system based on wearable and wireless instrumented garments, which are able to detect user specific physiological signals; . intelligent system for data representation and alert functions for creating intelligent feedback and deliver information to a target professional; . electronic devices for signals transmission by using 3G wireless network, allowing monitor the patient ‘‘anywhere’’; . advance telecommunication protocols and services; . effective and user-friendly data format. WEALTHY solution will be validate in 2 pilot sites, with an active participation of users and health care institutions. .
Research deliverables (academic and industrial) Intermediate results will generate mock-up versions of the WEALTHY platform, available in month 13. These comprise a mock-up interface, a mock-up device and a mock-up monitoring system. In month 19 the versions of the components and service will be available: beta interface, beta device and beta monitoring system. Publications De Rossi D., Della Santa A. and Mazzoldi A. (1999), ‘‘Dressware: wearable hardware’’, Material Science and Eng. C, Vol. 7, pp. 31-5. De Rossi D., Lorussi F., Mazzoldi A., Orsini P. and Scilingo E.P. (2002), ‘‘Active dressware: wearable kinaesthetic systems’’, Sensor and Sensing in Biology and Engineering (in press). Scilingo E.P., Lorussi F., Mazzoldi A. and De Rossi D. (2002), ‘‘Strain sensing fabrics for wearable kinaesthetic-like systems’’, IEEE Sensors Journal (in press).
Riga, Latvia Institute of Textile and Clothing Technology, Riga Technical University, Latvia. Prof. Dr habil sc. ing, Austrums Klavins Research staff: Assoc. Prof. Dr habil sc. ing, V. Priednieks, Lecturer I. Ziemele, postgraduate (Master and doctoral study programs) students
Control, optimisation and monitoring of the stitch formation process in sewing machines Other partners: Academic None
Industrial Company ‘‘Promshveymash’’ Orsha, Byelorussia (1969-1991) Sewing Company ‘‘Latvia’’ from 1991
Project started: 1969 Finance/support: N/A Source of support: N/A Keywords: Sewing machines, Stitch
Project ends: No limit
Effective operation of sewing machines is of crucial importance for the qualitative production of sewn goods. It is possible to attain it by improving the mechanisms of the machine, controlling and monitoring them. These problems are being solved by applying mathematical methods of statistics, theory of probability and experimental design. The research is based on the unconformity of interaction of stitch formation tools (mechanisms) and needle thread as a complex parameter which permits one to estimate the process as a whole in each cycle and to simulate this process. It allows one to find out the impact of separate mechanisms, to improve the quality of the stitch formation process, so that it is possible to control, optimise and monitor them. On this basis the sewing machines are modernised or rationally used in mass production lines. Project aims and objectives . To work out the investigation methods of the sewing machine process. . To develop methods of the basic, complex parameters control, optimization and monitoring. . To develop practical methods for increasing the sewing machine’s serviceability, improving separate mechanisms of the machine. . To work out methods for the selective application of sewing machines for a rational organization of mass production lines in the garment industry. Academic deliverables . The following part of the study programs for Master’s has been worked out, namely, control and monitoring of the sewing machine process. . The results of the research have been used by doctoral students acquiring investigation methods. Industrial deliverables . Control, monitoring and improving the quality and serviceability of sewing machines. . Rational organization of garment mass production lines. Publications Aizpurietis, A.V., Klavins, A.R., Poluhin, V.P. and Sharamet, U.I. (1988), ‘‘Raschot chetirjohzvennogo mechanizma nitepritjagivatelja shvejnih machin na EVM’’, Journal Tehnologia logkoi promishlennosti, Moscow, Vol. 6, pp. 94-7.
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Klavins, A. and Priednieks, V. (1998), ‘‘The quality improvement problems of the operation sewing machines and the prospects of the development of scientific research’’, Scientific Conference of ‘‘Technologies and Design of Consumer Goods’’, Kaunas University of Technology, 21-22 April. Klavins, A.R., Salenieks, N.K. and Rachok, V.V. (1974), ‘‘Diagramma ispolzovanija igolnoi niti’’, Machinostrojenie dija logkoi promishlennosti, Moscow, No. 3, pp. 3-7. Olshanskij, V., Fedoseyev, G. and Klavins, A. (1987), ‘‘Raschot parametrov prushinih kompensatorov shvejnih mashin’’, Journal Tehnologia logkoi promishlennosti, Moscow, Vol. 4, pp. 114-15. Priednicks, V. and Klavins, A. (1997), ‘‘The optimization of lockstitch formation system in sewing machines’’, The 78th World Conference of The Textile Institute in Association with the 5th Textile Symposium of SEVE and SEPVE, Vol. 11, Thessaloniki, Greece, pp. 195-204. Some Adjusting Techniques for Sewing Machines, Pat (USSR) 442252. IPCl D 05 B 69/24. The Method for Plotting Needle Thread Take-up Curve, Pat (USSR), Nr. 324322 IPCI. D. 05 B45/00. The Method for Plotting Needle Thread Take-up Curve, Pat (USSR), Nr. 461189 IPCl. D. 05 B45/00. Ziemele, I., Klavins, A. and Priednieks, V. (1997), ‘‘Selection of lockstitch sewing machine obtaining a high quality of thread joints in garment’’, abstract of the papers presented at the 26th Textile Research Symposium at Mt Fuji, Shizouka, Japan, 3-5 August, pp. 60-3.
Riga, Latvia Institute of Textile and Clothing Technology, Riga Technical University, Latvia Prof. Dr habil. sc. ing. Viktoria Kancevicha Research staff: Prof. Dr habil. sc. ing, V. Kasyanov, Assoc. Prof. Dr sc. ing. H. Vinovskis, postgraduate (Master and doctoral study programs) students
Development of new textile technology for manufacturing hybrid textile vascular grafts Other partners: Academic Latvian Medical Academy Project started: 1980 Finance/support: N/A Source of support: N/A Keywords: Technology, Textiles
Industrial None Project ends: No limit
In the fields of medicine and bioengineering extensive efforts have been directed to the development of various new types of vascular grafts using different technologies. The textile industry has a lot of practical experience in the production of different kinds of vascular grafts and allows a high production rate to be reached.
Nevertheless there are practical needs for compliant grafts for patients with cardiovascular disease. Clinical implantation and chronic experiments on animals with various grafts have indicated a fairly good correlation between their compliance and patency (especially for a diameter less than 6 mm) because the compliance vascular graft practically does not change the haemodynamics of the blood flow. Thus compliant vascular grafts having mechanical properties matching the human arteries are very promising for successful reconstruction operation and good patency. This problem of developing new textile technology and producing compliant vascular grafts is very important for Latvia because cardiovascular disease is very high – and not only in the Baltic states. The investigation of the peculiarities of the mechanical behavior and structure of human blood vessels is carried out at RTU. On this basis the new structure of the hybrid textile materials is developed. Using the system of two threads having substantially different modulus of elasticity, it is possible to model peculiarities of the biomechanical behavior of the arterial tissue. Project aims and objectives . Development of the new textile technology for manufacturing novel hybrid compliant vascular grafts using knowledge of the biomechanical properties and structure of human arteries. . Manufacturing of novel compliant hybrid vascular grafts with biomechanical properties matching the host arteries. . Establishing the new principles of the manufacturing of the hybrid material composed of two different types of threads for creation of the reinforced composite structure applicable to different engineering purposes. As expected, these structures will provide unique properties and will be characterised by improved reliability and durability. Academic deliverables . The part of the study Masters program in textile technology has been worked out. . The methods and results of the research have been used in Doctoral study programs. Industrial deliverables The new textile technology for manufacturing novel hybrid compliant vascular grafts. Publications Chnourko, M. and Kancevich, V. (1998), ‘‘Woven textile biomaterials international conference’’, Textiles Engineered for Performance, UMIST, Manchester, 8-11 July. Kancevicha, V. and Kasyanov, V. (1994)., ‘‘Small diameter blood vessel prostheses’’, Fibres and Textiles in Eastern Europe, Vol. 2 No. 3, pp. 32-3.
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Kancevicha, V. and Kasyanov, V. (1996), ‘‘Crimp vascular graft’’, Latvian Patent, Nr. 10836. Kancevicha, V. and Kasyanov, V. (1998), ‘‘Crimp vascular graft’’, Latvian Patent, Nr. 12175. Kasyanov, V., Purinya, B. and Kancevich, V. (1994), ‘‘Compliance of human blood vessels and novel textile vascular grafts’’, Abstracts of Second World Congress of Biomechanics, Amsterdam, The Netherlands, 10-15 July, Vol. 1, p. 28. Kasyanov, V., Kancevich, V., Purinya, B. and Ozolanta, I. (1996), ‘‘Design of biomechanically compliant vascular grafts’’, 10th Conference of the European Society of Biomechanics, Leuven, 28-31 August, p. 26. Kasyanov, V., Kancevich, V., Purinya, B., Izolanta, I. and Ozols, A. (1998), 1st Conference of the European Society of Biomechanics, Toulouse, 8-11 July.
Riga, Latvia Institute of Textile and Clothing Technology, Riga Technical University, Latvia. Associate Professor, Dr sc. ing. Ivars Krievins Research staff: Msc, Dipl. ing. V. Sorokins, Msc, Dipl. ing. S. Valaine, postgraduate (Master and doctoral study programs) students
Latvian clothing market product oriented research Other partners: Academic Terminology Committee of Academy of Sciences
Industrial Ministry of Light Industry of Latvia (1988-89) Ministry of Economics of Latvia (1997–98) Lauma Co., Liepaja, Latvia (1996–97) Project started: 1988 Project ends: No limit Finance/support: For particular objectives Source of support: N/A Keywords: Clothing, Fashion General long-term Latvian clothing market studies embrace common information areas met through market secondary (desk) research. Mainly it is based on the analysis of the Latvian 8000 household budget survey data and others available, e.g. pricing statistical data. The results of the Latvian clothing market general monitoring are oriented towards use in academic and industrial fields. In addition, the results are used for planning of primary clothing market research within a narrower in-depth range of clothing products. The morphological structure of ladies’ underwear demand has been determined by the studies of catalogues, that of corresponding retail outlets and by
administering questionnaires to 300 respondents on their actual and planned underwear wardrobe in 1997. In order to carry out the inquiry, Latvian/Russian terminology has been developed for naming illustrated product characteristics of the questionnaires. An elaborated thesaurus of clothing production terms is included in wider consumer education programmes as well as in the academic and professional ones. Conceptual analysis can be used for coordination and subordination of the educational contents within different levels and sectors of clothing education. Project aims and objectives . General monitoring of Latvian clothing market size and segmentation trends. . Distribution of consumer preferences by morphological attributes within in-depth analysis of clothing products. . Simulation of the garment quality evaluation based on consumer perception/satisfaction analysis. Academic deliverables . Morphological simulation of clothing product differentiation. . Comprehensive clothing quality evaluation methodology. . Mathematical simulation of clothing sizing. . Dictionary of Latvian/Russian clothing terms as the basis for product information processing. Industrial deliverables . General information on Latvian clothing market. . Particular information on the women’s underwear style preferences in Riga, 1997. . Feasibility of textiles and clothing standardization items in Latvia. Publications Blinkens, P., Be¯zina, V. and Krievins˘, I. (1989), Tekstilr & u¯pniecibas terminu v & a¯rdnica, Zina¯tne Riga, 855, 1p. (Dictionary of 14,000 textile terms). Der lettische Textil- und Bekleidungsmarkt = LR tekstiliju un apgerbu tirgus – Riga (1997), 57 S. (German/Latvian: Latvian textiles and clothing market, Desk research). Krievins, I. (1996), ‘‘Systematization of clothing technology concepts for Latvian terminology’’, (Lengvsios pramones tehnologios ir dizainas), Kauno, pp. 221-8. ‘‘Rigas sievies˘u apaks˘g`e rbu pieprasi-juma struktu¯ra’’ (1997), gada¯, ZPD pa¯rskats; Riga, 97,1p (Structure of ladies’ underwear demand in Riga).
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Riga, Latvia Institute of Textile and Clothing Technology, Riga Technical University, Latvia Prof. Dr habil sc. ing. Silvia Kukle Research staff: Assoc. Prof. Dr sc. ing. A. Vilumsone, Lecturer I. Vilumsone, Postgraduate (Master and doctoral study programs) students
The investigation of the geometry and composition of Latvian folk art designs Other partners: Academic Latvian Council of Science 1989-1996 Project started: 1989 Finance/support: N/A Source of support: N/A Keyword: Textiles
Industrial Latvian Crafts Chamber, 1993-present Project ends: No limit
Folk art is the form of ethnic consciousness to consolidate not only people of one nation but also of many generations. It is a means for manifesting and forming the specific face of the country and investment in the worldwide cultural heritage. We started our work on computerized collections in 1989, involving scholars of our university and many generations of students. As a result, material from museum and private collections and published works were collected together and systematized and presentations were prepared. The data address different users and applications, such as teaching materials to support school and university courses such as home economics, crafts technologies, ethnography ornamentation and composition; teaching materials for craftsmen for use in design studies libraries to support reproduction for local users – householders, artists and tourist markets; as a source of ideas – motifs and symbols, technologies, ways of material combination with different properties, fashions, placement of ornamentation, compositional solutions, creation of motifs, methods of designing double-face ornamented fabrics, pattern designing; methods of forming color ranges; leveraged space filling; fantasy for imagination. The other application is a well organized source of multipurpose scholastic studies, for example, to sort and classify, to study decoration methods and/or technologies, to find out rules; ethnographic studies, historical studies; regional studies; ethnoastronomy studies, linguistic studies.
Project aims and objectives Aim: Creation of the computerized knowledge basis of Latvian folk designs, crafts, technologies and tools. Objectives: Creation of the image and text libraries for different groups of folk textiles (mittens, table cloths, towels, girls’, women’s and men’s folk costumes, blankets), woodwork tools; investigation of basic rules followed in forming motifs, symbols, compositional groups and composition; investigation of the colour, symbol preferences in different regions and products; comparative analysis of ornamentation traditions in Latvian and Lithuanian folk art; analysis of the information structure and creation of the codification system; calculation of data leading system. Academic deliverables New knowledge supplementing basics of Latvian folk art; creation of new methods of investigation; creation of databases for further investigations; investigation of the use of prehistorical symbols and signs in Latvian border patterns, comparison with other ancient cultures; creation of the system of hypothesis; highly systematized teaching materials supporting different study courses. Industrial deliverables Methods of motifs’ creation, organization of rhythms, color ranges, border and panel type compositions; methods of creation of two face fabric designs; library of designs for reproduction (crafts companies, crafts people, students) and as an inspiration for new designs (artists, craftsmen, designers, students), knowledge of folk art basics (artists, craftsmen, designers, technologists). Publications Kukle, S. (1993), Geometry of Latvian Designs, thesis of Dr habil ing dissertation, Latvia. Kukle, S. (1995), Geometry of the Crosses and Diamond Type Signs Preferably Used in Latvian Folk Designs. The Investigation and Optimization of the Textile Technology, Riga, Latvia, pp. 67-78. Kukle, S. (1996), ‘‘Computer graphics as a tool giving unambiguous results’’, poster abstracts, 2nd World Congress on the Preservation and Conservation of Natural History Collections, University of Cambridge, 20-24 August. Kukle, S. (1997), ‘‘Latvian border patterns, Lengvosios pramones technology’’, Kauno tecgnologijos universitetas, Lithuania. Kukle, S., Vilumsone, A., Vilumsone, I. and Kikule, D. (1996), ‘‘Database of Latvian folk designs’’, poster abstracts, 2nd World Congress on the Preservation and Conservation of Natural History Collections, University of Cambridge, 20-24 August. Vilumsone, I., Kukle, S. and Zingite, I. (1995), ‘‘The ornaments and rhythms of sashes of Alsunga (town on Western Baltic seaside)’’, The Investigation and Optimization of the Textile Technology, Riga, Latvia, pp. 54-60.
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Riga, Latvia Institute of Textile and Clothing Technology, Riga Technical University, Latvia Tel: 00371 708 9333 Assistant Professor Ilze Baltina, Department of Mechanical Technology of Fibre Materials Research staff: Assistant Professor I. Brakch, Associate Professor H. Vinovskis and postgraduate students
Wool carbonizing in the radio frequency electromagnetic field Other partners: Academic None
Industrial Textile factory at Kustanai (Kazakhstan) 1992-present Textile factory at Cernigov (Ukraine) 1993-1995 Textile factory ‘‘Riga tekstils’’ (Latvia) 1991-1994 Project started: 1989 Project ends: No limit Keywords: Electromagnetics, Radio, Wool In wool carbonizing the baking process is usually carried out at very high temperatures, 120-125 C, but sometimes also at 130 C. At such temperatures wool decomposes and turns yellow. It is advanced by a high concentration of sulphuric acid solution. In the new method, instead of baking with hot air, there is inclusion of radio frequency electromagnetic field, which creates vegetable matter energy that is extracted as heat. Wool temperature does not exceed 100 C and end moisture is 10-15 per cent, but vegetable matter temperature is sufficient for hydrolysis. Sulphuric acid concentration in this case does not exceed 35–40 per cent. Wool fibre rapid hydrolysis and dissolution occurred when the acid concentration ranged from 40 per cent up. Project aims and objectives To work out new carbonizing technology in which vegetable matter can be removed maximally, but wool fibre damage is very low. Academic deliverables Practice and new knowledge for Master’s and postgraduate students.
Industrial deliverables New carbonizing technology which prevents wool damage during carbonizing. Publications Baltina, I. and Brakch, I. (1997), ‘‘Wool carbonizing in a radio frequency electromagnetic field’’, World Textile Congress on Natural and Natural-Polymer Fibres, University of Huddersfield. Baltina, I. and Reihmane, S. (1998), ‘‘Use of cellulose production waste product lignosulphonate in carbonisation of wool’’, 7th International Baltic Conference on Materials Engineering, Jurmala, Latvia, pp. 161-5. Zarina, I. (Baltina, I.), Reihmane, S., Braksch, I. and Liepa, I. (1995), ‘‘Wool carbonizing methods’’, Progress in New Polymer Materials: Seminar Materials of TEMPUS Programme, Riga.
Selkirkshire, Scotland Heriot-Watt University, Netherdale, Galashiels, Selkirkshire, Scotland Tel: 01896 892136; Fax: 01896 758965; E-mail:
[email protected] School of Textiles George Stylios, Bert Mather, Bob Christie, Dean Robson, The School of Textiles, Heriot-Watt University
Engineering the performance and functional properties of technical textiles Other partners: Academic UMIST University of Leeds
Industrial British Textile Technology Group Industrial Member companies
Project started: 1 December 2002 Project ends: 31 August 2004 Finance/support: £1,000,000 Source of support: Department of Trade & Industry Engineering and Physical Science Research Council Keywords: Industrial textiles, Non-woven, Biomedical, Fibres, Yarns, Fabrics, Garments Technical textiles are defined as textile materials and products manufactured for their technical performance and functional properties rather than their aesthetic and decorative characteristics. Despite market predictions for technical textiles,
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and incremental advances in some companies, many fundamental problems relating to the engineering and development of technical textiles remain to be solved; these become more urgent due to fierce global competition. There are many areas that still employ subjectivity and tradition that hinder the leap forward the sector needs to enable the development of new products and applications of textiles as engineered materials. Structural mechanics of textiles has been researched extensively, focusing on the understanding of simple textile structures mainly for apparel applications. Whilst such research may have solved specific problems, there are serious limitations to the production of generic solutions for precision engineering and manufacture of technical textiles, due to the inherent complexity of technical textile materials and their structures. Limited research has been carried out on the engineering of other properties such as thermal and fluid, which are equally important for the engineering of technical textiles. Consultation within the academic community, and with industrial members of the TechniTex Partnership over the past 12 months has established three key themes of research required to enable the proposed underpinning platform of knowledge to be established. These mutually dependent themes are modelling (to enable 3D design, simulation, and visualisation), measurement (to define and understand the relationships between structure, performance, and functionality), and manufacture (to enable appropriate manufacturing conditions to create the engineered textile). Within each a fundamental understanding of materials is required. The three themes are reflected in the technical textile challenges. To ensure the industrial relevance and applicability of the theme-based research proposed, it is not possible to explore each theme in isolation. As shown above the level of mutual dependency requires that an integrated programme of research be conducted. Project aims and objectives The rapidly growing technical textiles industry draws ideas and expertise from a diverse range of academic groups and disciplines. The aim of the TechniTex core research programme is to formalise and extend this distributed generic body of knowledge relating to textiles. This extended and integrated body of knowledge will generate a platform for the creation of methodologies for specification, design and manufacture of technical textiles, and relate performance and functionality with manufacturing processes. The specific objectives are to: . establish databases of existing technical textiles, associated technical data, and the associated body of knowledge; . classify existing technical textile structures on the basis of their function, properties, and end use;
. .
.
.
.
.
.
. .
.
classify processing conditions for fibres, yarns, and fabrics; identify missing data in terms of structural and mechanical detail, and fibre and yarn properties; research and develop new and enhanced test methods and equipment for technical textiles; generate new data to further establish the body of knowledge on existing yarns, fibres and fabrics; establish the performance criteria necessary for technical textiles appropriate to their end use; create geometric and mechanical models of technical textile structures using the derived classification and data; create predictive models for these processes specific to the demands of technical textiles, and to optimise their manufacturing conditions to fulfil the specified performance criteria; conduct an experimental programme for the verification of the models; create interfaces between the models and generate an integrated suite for the engineering of technical textiles; conduct a programme of dissemination and technology transfer through established TechniTex Faraday practices.
Research deliverables (academic and industrial) . an integrated suite of databases encapsulating the body of knowledge on technical textiles; . geometric models for visualisation and input into performance modelling; . mechanical models for performance and manufacturability; . new and enhanced test methods and equipment; . new standards for the specification and manufacture of technical textiles; . methodologies for the creation of engineered technical textile structures; . methods for optimising manufacturing conditions, processes and materials geared to the specific needs of these engineered structures; . a technology transfer pathway through to the wider industrial and academic networks of the TechniTex Partnership. Publications Russell, S.J. and Mao, N. (2000), ‘‘Directional permeability in homogeneous nonwoven structures. Part 2: permeability in idealised structures’’, J. Text. Inst., Vol. 91, pp. 344-58. Bandara, P. and Islam, S. (1991), ‘‘Yarn spacing measurement in woven fabric with special reference to start-up marks’’, J. Text. Inst., Vol. 87, Part I, pp. 107-19.
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Finn, J.T., Sagar, A. and Mukhopadhyay, S.K. (2000), ‘‘Effect of imposing a temperature gradient on moisture vapour transfer through water resistant breathable fabrics’’, Tex. Res. J., Vol. 70 No. 5, pp. 460-6. Partridge, J.F., Mukhopadhyay, S.K. and Barnes, J. (1998), ‘‘Dynamic air permeability behavior of Nylon66 air bag fabrics’’, Text. Res. J., Vol. 68 No. 10, pp. 726-31. Potluri, V.V.P., Atkinson, J. and Porat, I. (1992), ‘‘Performance assessment of a robot for use in a fabric test cell’’, 29th International Matador Conference, Manchester, April.
Selkirkshire, Scotland Heriot-Watt University, Netherdale, Galashiels, Selkirkshire, Scotland Tel: 01896 892136; Fax: 01896 758965; E-mail:
[email protected], Professor G.K. Stylios, School of Textiles Research staff: Ms Fan Han
HOMETEX: a virtual trading centre for textiles Other partners: Academic None
Industrial OCF Ltd Silicon Graphics Inc. Scottish Enterprise Borders Scottish Textiles Manufacturers Association Borders Textile Forum Project ends: 31 August 2004
Project started: 1 September 2001 Finance/support: £1,000,000 Source of support: EU ERDF Objective 2 Keywords: Drape, Augmented reality, Virtual trading, Home shopping, 3D simulation, Dynamic draping In recent years we have witnessed a revolution in networking of information on a global scale via the Internet. Many companies have capitalised on this provision and have used it in many diverse ways, from electronic mailing to marketing, selling and trading of products and services. Marketing and selling of limp products such as textiles and, particularly, garments using new multimedia techniques would be extremely beneficial to the industry, since it would enable companies to reduce product to market, to enhance product development through 3D visualisation and to trade
directly without the intervention of retailers. But selling of garments is not as easy as selling other commodities; garments are made of limp materials which take up the configuration of the wearer; customers would in most cases like to wear the garment, or, in the case of buyers, see the garment worn by a model. For the effective exploitation of these possibilities, we should, therefore, develop a multimedia environment to enable the simulation of drape behavior of garment designs on virtual models who may resemble real customers. The textile industry chain, being a traditional industry, is very conservative in the use of multimedia for manufacture, advertising and/or sales. The reason is firstly because the industry consists of small companies which do not have the resources to use multimedia technologies effectively without training, and secondly there is no technological infrastructure available to realistically visualise new products from home. This project aims to pilot such possibilities which have other benefits to this industry in terms of ‘‘just-in-time’’ manufacture, 3D visualisation of new products and better communication with their customers. Project aims and objectives The main objectives of this scheme are as follows: . To develop a virtual Home Trading Centre for the textile, clothing and retailing industries: ‘‘HomeTex’’. . To enable the production of virtual fashion shows for buyers through CD-ROM and Internet presentations. . To network 40 companies with 500 homes (directly) via the technology and to regularly upgrade and manage company trade data, for piloting the technology. . To establish and provide through ‘‘HomeTex’’ other trade data, real-time electronic mail, Tele Trading and, possibly, banking. . To enable textile and clothing companies to interface with this technology so that new products can be made much faster and to minimise energy, raw materials and other resources. . To network with other services, such as Cyber Tex and SPIN. Research deliverables (academic and industrial) A Virtual Trading Centre in Textiles operating from the Borders of Scotland. Publications Stylios, G.K. and Wan, T.R. (1998), ‘‘A new collision detection algorithm for garment animation’’, International Journal of Clothing Science and Technology, Vol. 10 No. 1 pp. 38-49. Stylios, G.K. and Zhu, R. (1998), ‘‘The characterization of static and dynamic drape of fabrics’’, Journal of the Textile Institute, Vol. 88 No. 4, pp. 465-75.
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Stylios, G.K., Wan, T.R. and Powell, N.J. (1996), ‘‘Modeling the dynamic drape of garments in synthetic humans in a virtual fashion show’’, The International Journal of Clothing Science and Technology, Vol. 8 No. 3, pp. 44-55. Stylios, G.K., Wan, T.R. and Powell, N.J. (1995), ‘‘Modeling the dynamic drape of fabrics on synthetic humans: a physical lumped parameter model’’, International Journal of Clothing Science and Technology, Vol. 7 No. 5, pp. 10-25.
104
Zagreb, Croatia Faculty of Textile Technology, University of Zagreb, Pierottijeva 6, 10000 Zagreb, Croatia Prof. Dr Ruz˘ica C˘unko, Department of Textile Chemistry and Testing of Materials Research staff: Dr Maja Andrassy, Dr Emira Pezelj, Dr Mirjana Gambiroz˘a-Jukic´, Vera Fris˘c˘ic´, Biserka Vuljanic´, Antoneta Tomljenovic´, Marija Kovac˘evic´
Ecological aspects of fiber properties and quality of textiles Other partners: Academic Industrial None None Project started: 1 June 1997 Project ends: – Finance/support: N/A Source of support: Ministry of Science and Technology of the Republic of Croatia Keywords: Ecology, Textiles Research activities proposed are related to the environmental aspects of textile materials and will include investigations of the impact of some environmental parameters on fiber properties, as well as the investigations of a possibility of evaluating textile products on the basis of their ecological safety. Textile products interact with their environment, which influences the changes occurring in them, covered by the term ‘‘ageing’’. The changes are complex and varied and in most cases quite specific and sophisticated investigations are necessary to understand them. The investigation of fibre ageing under the influence of UV-radiation, ozone and pollutants, is supposed to contribute to understanding the mechanism of the changes on molecular, structural and morphological levels. The other research task deals with the problem of a possible harmful influence of textiles on human health, covered by the expression of ‘‘human-environmental safety’’. This kind of safety has become one of the basic prerequisites, when speaking about the quality of textile products, and the most important one when trying to sell on the European
market. The investigations are supposed to create basic prerequisites for laboratory evaluation of humane-environmental safety. Part of the research task concerns modification of fibre properties using ultrasound waves, as an environmentally very acceptable solution. The effect of ultrasound waves will be investigated on cellulose fibres, polypropylene, polyamide, polyester and wool. The results will be published in scientific research periodicals and conferences, making possible their usage, checking and evaluation. Project aims and objectives In the area of polypropylene and aramide fibres ageing the aim is to complete the investigations started by the previous project, especially concerning the impact of atmospheric pollutants, sunlight, weather conditions and ozone concentration in various stress conditions. The second aim is to investigate possible modifications of fibre properties through the application of ultrasound, and the third aim is to create a scientific and expert basis for testing and objective evaluation of human-environmental safety as a basic prerequisite for textile quality assurance. Publications C˘unko, R. and Pezelj, E. (1997), ‘‘The ageing of polypropylene through environmental agency’’, The 78th World Conference of Textile Institute, Thessaloniki. C˘unko, R., Andrassy, M. and Pezelj, E. (1998), ‘‘Elimination of polyester fibre oligomers using ultrasound waves’’, Proceedings TEXSc ’98, Liberec. C˘unko, R., Pezelj, E. and Andrassy, M. (1997), Tekstil, Vol. 46, pp. 677-83. Pezelj, E., C˘unko, R. and Andrassy, M. (1997a), ‘‘The effect of global climatic change on the fibre ageing’’, Proceedings Slovenia Chemical Days. Pezelj, E., C˘unko, R. and Andrassy, M. (1997b), ‘‘The influence of repeated maintenance treatments on properties of PP fibers’’, Proceedings The 78th World Conference of Textile Institute, Thessaloniki.
Zagreb, Croatia University of Zagreb, Faculty of Textile Technology, HR-10000 Zagreb, Croatia Tel: ++385 (1) 37 03 153; Fax: ++385 (1) 37 74 029; E-mail:
[email protected] Edita Vujasinovic, Department of Textile Chemistry and Material Testing
Sorption characteristics of medullated wool fibres Other partners: Academic None
Industrial None
Research register
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Project started: 1999 Project ended: 2001 Finance/support: 3,000 DEM/year Source of support: Croatian Ministry of Science and Technology Keywords: Textiles, Wool, Sorption, Medullated wool From 500 to 700 tons of greasy wool are sheared in Croatia every year (annual statistics of Croatia 1990-1995). Because of the widely heterogeneous character of the wool sheared, the number of different breeds of sheep, inadequate shear preparation and extremely high content of medullated fibres (Tekstil, Vol. 41 (1992), 591; Stocarstvo, Vol. 48 (1994), 443), coarse wool of domestic sheep is not used in the textile and garment industry. Under these conditions, the quantities of wool stated cease to be a useful raw material and become an ecological hazard. Some developed European countries are faced with the same problem (Nuova Sel Tess, Vol. 5 (1996), 28), and, as coarse wool, due to high content of medullated fibres, can be a useful absorbing and insulating material (both sound and heat insulating), investigations were started to establish the possibilities of using domestic wool as raw material in the manufacture of technical textiles for a wide range of applications (e.g. in civil engineering, building and construction, agriculture and some other branches of industry). Investigations of the physicochemical (and especially absorptive) properties of medullated wool fibres will show how they can be used in the manufacture of technical textiles, such as various filters, agro-, geo- and thermo-textiles. In this way, coarse domestic waste wool will be used as an environmentally and economically acceptable product, which is in tune with European and global trends of more a rational managing of natural resources, with the purpose of preserving and protecting the environment. Project aims and objectives The quality of most of the domestic wool does not meet the technological requirements stated by the Croatian wool industry, meaning that it is an industrial raw material that cannot be utilised. The aim of the investigation proposed is to explore the possibilities of using coarse domestic wool as a raw material in the manufacture of technical textiles. Fine wool fibres are appropriate, ecologically acceptable and a cheap natural raw material for the textile garment industries. Coarse wool fibres are most often a by-product of sheep breeding, which cannot be properly used. The results of investigating the physio-chemical, and especially absorptive, properties of medullated wool fibres will indicate the feasibility of using such fibres as a proper absorbing material (primarily for liquid and solid waste), in the manufacture of a wide range of technical textiles, such as filters, geo-, agro-textiles, sound and heat insulators, etc. In this way, coarse domestic wool, which has become harmful waste through
burning without control and years of depositing, will be used as an environmentally acceptable and economically profitable product. Publications Raffaelli, D., Dosen-Sver, D. and Vujasinovic, E. (1999), Kemija u Industriji, Vol. 48 No. 5, pp. 189-96. Vujasinovic, E. and Andrassy, M. (2000a), Proceedings of the 4th International Conference TEXSCI 2000, Liberec, Czech Republic, 12-14 June, pp. 84-8. Vujasinovic, E. and Andrassy, M. (2000b), Tekstil, Vol. 49 No. 6, pp. 277-86.
Research register
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Research index by institution
IJCST 14,6
108
Institution
Page
Bolton Institute, Bolton, UK
6-7
Budapest University of Technology and Economics, Hungary
9-12
Clemson University, USA
80-86
Dresden University of Technology, Germany
12-13
Ege University, Izmir, Turkey
19-26
Heriot-Watt University, Selkirkshire, Scotland
99-104
Hong Kong Polytechnic University, Kowloon, Hong Kong
33-39
Kaunas University of Technology, Lithuania
26-30
Kyoto Institute of Technology, Japan
50-55
Leeds Metropolitan University, UK
55-56
Louisiana State University, USA
60-61
Manchester Metropolitan University, UK
61-69
Philadelphia University, USA
86-88
Queens’ University, Belfast, UK Riga Technical University, Latvia
5-6 90-99
Satra Technology Centre, Kettering, UK
31-33
Technical University of Liberec, Czech Republic
56-59
University of Bradford, UK
7-8
University of Guelph, Ontario, Canada
78-80
University of Maribor, Slovenia
70-73
University of Minho, Portugal
73-76
University of Newcastle upon Tyne, UK
76-78
University of Pisa, Italy
88-90
University of Twente, The Netherlands
13-19
University of Zagreb, Croatia
104-107
Yeungnam University, Korea
39-49
Research index by country
Index by country
Country
Page
Canada
78-80
Croatia
104-107
Czech Republic
56-59
Germany
12-13
Hong Kong
33-39
Hungary
9-12
Italy
88-90
Japan
50-55
Korea
39-50
Latvia
90-99
Lithuania
26-30
Portugal
73-76
Scotland
99-104
Slovenia
70-73
The Netherlands
13-19
Turkey
19-26
UK
5-8, 31-33, 55-56, 61-69, 76-78
USA
60-61, 80-86
109
Research index by subject
IJCST 14,6
110 Subject Automated garment assembly, grippers, vibration of panels Body scanning, moire, visualisation Cavitation, convective diffusion Cellulose, cotton fabrics, bioscouring, pre-treatment of cotton, quaternary ammonium compounds, tetramethylammonium hydroxide, swelling mercerisation Comfort, clothing, design, waterresistance, membranes, stretch/pressure garment, ergonomics Composite, thermoplastic, tow opening, reinforced fibres Dimensional stability Dyeing, reactive Energy saving Environment, oxidative catalysts, ecology Enzyme technology, hydrolysis Fabric fingerprinting properties, shell, structure, deformation, jamming, geometry, behaviour, prediction Fabrics, knitted, woven, drawn worsted yarns, silk and worsted like, easy-care, antishrink, PET composite yarn knitted fabric, bulkiness, disk twisting High energy irradiation Intimate apparel, lingerie, design Ironing, effects of heat, moisture, pressure, robotic ironing, automated garment assembly Knitted fabrics and products Mass transfer, water vapour transfer, layered clothing, cooling
Page 77, 78 35 13 6, 9, 15, 16, 20, 23, 25
31, 33, 38, 66, 67 54, 55 5 20, 23 20, 25 18, 24, 25, 104 9, 15, 16, 17 5, 8, 28, 29, 32, 67, 68, 69 39, 40, 41, 43, 48, 51, 86-88
10 34 71, 72, 73, 76, 77 86, 87, 88 13, 62-65
Measurement systems, image analysis, hand evaluation, degradation performance, sensory method, shingosen fabrics, ergonomic clothing comfort, mechanical testing equipment Medical textiles, antimicrobial, blood circulation, compressive clothing, stretch/pressure garment, physiology, knitwear, bioscouring, disposable garments, healthcare, sterilisation, wearable health care system, vascular grafts Microwave energy Nanotechnology Objective measurement, wave fabrics, knitted fabrics, dynamic surface tension, roughness, contact angle, shearing, bending, buckling, technical textiles, biaxial, punching, sterilisation PCS filament threads, sewing PET, properties of, quality of, composite yarn and garment Protective clothing, pesticides, performance clothing, internal condensation, layered clothing, cooling garment, agriculture, industrial Rayon fabrics, causticising, moistening, printing, rayon Recycle paper fibres RF dryer Sorption capacity Sourcing data base, data mining, intelligent search, textiles Stitch formation, sewing, optimisation of sewing conditions
5, 8, 13, 19, 26, 29, 32, 52, 53, 54, 55, 58, 59 11, 13, 16, 38, 73-76, 88, 89, 90, 92-94
20 19 7, 13, 19, 26, 27, 28, 29, 52, 53, 67, 68, 99-103 70, 71 39, 40, 46 11, 78-80
20, 21, 62-65 9, 15 20 10 60, 61 8, 90-92
Strategy, direction, networking, marketing, product oriented research Supply chain, quality, UK retailing, balanced inventory, flow system, ordering Surface modification, fibres Swimwear, degradation Technical textiles, functional, performance, engineering, performance fabrics, measurement, surface modification, fibres 3-D deformation, 3-D textiles, fabric modelling 3-Dimensional design, pattern, moire´ topography, visualisation, CAD,
39, 40, 42, 48, 49, 94, 95 61, 62, 80-86 9, 15 32 5, 27, 99-102
5, 6, 58, 59, 103 5, 6, 35, 50, 51, 55, 56, 96, 97,
simulation, lay planning, pattern nesting, genetic algorithm, virtual trading, folk art design Tuft formation, simulation of Weaving machines, vibration, shock Wet processing, finishing, scouring, bleaching, catalytic, dynamic wetting, surface tension, prediction, wet fastness, rubbing, ultrasound, UV light, laundering Wool medullated, sorption, electromagnetics, wool carbonising Wrinkling
102, 103
Index by subject
50 56-58 6, 13, 17, 18, 19, 23, 25
98, 99, 105, 106 6, 27
111
Research index by principal investigator
IJCST 14,6
112
Principal investigator
Page
Lopez-Lorenzo, M.
15-16
Abou-iiana, M.
86-88
Marques, M.J.A.
73-76
Agrawal, P.B.
16-17
Matsuo, T.
53-54
Alimaq, D.A.
57-58
McCartney, J.
5-6
Baltina, I.
98-99
Moholkar, V.S.
13-14
Borsa, J.
9-10, 10-11
Nakamura, M.
49-51
Chen, Y.
60-61
Nosek, S.
56-58
Crispin, A.J.
55-56
Pargas, R.
80-81
C˘unko, R.
104-105
Peck, J.
82-83
De Rossi, D.
88-90
Ro¨del, H.
12-13
Duran, K.
24-26
Ruckman, J.E.
Gersˇak, J.
67-69, 70-71, 71-73
61-62, 62-63, 63-64, 64-65, 65-66
Gutauskas, M.
27-29, 29-30
Simmons, A.
32
Slater, G.K.
78-80
Strazdiene, E.
26-27
Stylios, G.K.
7-8, 99-101, 102-104 50-53
Hayes, S.G.
66-67
Higgins, L.
6-7
Jarvis, C.
83-84
Kancevicha, V.
92-94
Suresh, M.N.
Kawabe, K.
54-55
Tarakc¸iogˇlu, I.
19-21, 21-22
Taylor, P.M.
76-77, 77-78
Kim, S.J.
39-40, 40-41, 42-43, 43-44, 44-47, 47-48, 48-49
Klavins, A.
90-92
Kolluru, R.
85-86
Krievins, I.
94-95
Kukle, S.
96-97
Ku˚s, Z.
58-59
Topalovic, T. Vujasinovic, E.
17-18 105-107
Witson, J.
7-8
Wilford, A.
31, 33
Yu, W. Yurdakul, A.
33-35, 35-37, 37-39 22-24
