DESIGNING AND PATTERNMAKING WITH STRETCH FABRICS 1
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Nareerut Jariyapunya, Jelka Geršak, Blažena Musilová, Smita Boob
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Technical University of Liberec – Faculty of Textile Engineering, Department of Clothing, Studentská 2, Liberec, Czech Republic
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University of Maribor – Faculty of Mechanical Engineering, Research and Innovation Centre for Design and Clothing Science, Smetanova 17, SI-2000 Maribor, Slovenia +420 773591414.
[email protected]
Abstract The pattern construction for woven fabric is considered to be very ordinary when comparing with the patterns construction for tight-fitting clothing characterized by its stretched fabric. Fabric elasticity is an important parameter, which plays a key role particularly when constructing patterns for tight-fitting clothing, in respect of changing pattern-piece size, resp. adapting the garment to the contours of a body in motion. The purpose of this research is to design 3D pattern construction with stretch fabric for women tight-fitting sportswear using OptiTex software to represent the tension properties of fabric generated on the surface of the simulation model. Moreover, the study on mechanical properties of stretch fabric and its result have illustrated that OptiTex could be used to simulate the tension map options so as to inspect its colored map depicting amounts of tension between clothing and model. It is certainly obvious that tension map area could be adjusted in accordance to the pattern design suitable for tight-fitting clothing wearing. Subsequently, the final pattern of 3D simulation would be compared with the actual clothing worn by rigid mannequin and also to be measured by PicoPress pressure tester.
Key words Stretch fabric, 3D pattern construction, Tension distribution, Tight-fitting, Pressure comfort
1. Introduction 3D virtual pattern construction representation of garment provides high potential for design clothing and development. Clothing industry rapidly turns to virtual simulation which not only presents realistic 3D view of garment but also simulates mechanical behaviour of materials. Elastic garments for sportswear has been providing comfortable movement, minimizing the risk of injury or muscle fatigue, and reducing friction between body and clothing [1]. Patterns construction for tight-fitting garments which very closely contour the human body. The moment the physical movement is made, the comfort performance level changes and different parts of the body stretch very differently, and the amount of stretch will vary differently in each direction [2]. J. Geršak [3] report that adjustment adapting an initial pattern of a tight-fitting garment is often done by decreasing the pattern-pieces. The garment patternpieces are often, in practice, reduced by subjectively evaluating fabric elasticity, using only a manual elongation test. A simple and ordinary body movement expands the skin by about 10–50% [4]. Pressure garments are defined as custom made elastic garments that exert pressure on the body by virtueof the fact that they are made smaller than the body they are designed to fit [5, 6]. Accounting for garment pressure and comfort sensations at the waist, they have observed that in the 2 lower garment pressure range (0–15 gf/cm ) no sense of discomfort is there. In the medium range of
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garment pressure (15–25 gf/cm ) negligible or only slight discomfort is perceived. But in higher 2 pressure range, i.e. when the garment pressure exceeds 25 gf/cm , extreme discomfort is perceived [7]. The Reduction Factor method reduces all of the size measurements by a standard amount, typically between 10 and 20% [5, 6], regardless of the fabric used. Krzywinski et al [8] evaluate elastic properties of a fabric, wearing tests will determine the necessary load to match adequate garment fit with required comfort during wear. Investigations have shown that the feeling of comfort when wearing −1 tight garments is reached at fabric elongation occurring at a load of 1.5 or 2.0 N (5 cm) . The Laplace Law method uses the Laplace equation to calculate the reduction factor for each circumferential measurement in order to deliver a specific pressure [8]. However, the Laplace Law method takes account of the fabric tension when calculating garment dimensions while the Reduction Factor method does not [9]. The compression tester PicoPress was used by Vinckx et al [10] estimating the pressure perturbation when PicoPress sensor is used to measure the interface pressure applied to a cylinder, which is used in the apparatus, as no other mathematical model is currently available to estimate this perturbation. The estimated value of perturbation was, then, used to apply a correction factor to the pressure values measured by PicoPress.
2. Experimental The research has been using stretch fabric to construct tight sportswear and its pattern by reducing its size in accordance with its pressure simulated by Optitex software. Simulation of tension map has shown different levels of physical tensions distribution on the sportswear model. Then the last suitable pattern adjusted by Optitex would be compared by Pico Press pressure measurement device. 2.1. Materials Two different types of stretch knitted fabrics were used: (a) the fabric containing 65% Polyamide 2 (PA), 35% elastane with 183 g/m and (b) fabric from 38% Outlast, 52% Polyester (PES) and 10% 2 Spandex with 151 g/m . The experiment using Fabric Assurance by Simple Testing (FAST) system and Kawabata Evaluation System for Fabrics (KES FB-Auto) to determine the parameter requirements with OptiTex 3D simulation. The experiment preparation, pre-conditioning and testing were carried out under standard atmospheric conditions of 20 ± 2 °C temperatures and 65 ± 5% relative humidity. 2.2. Methods The properties of stretch fabrics requirment from Optitex simulator software for input parameters 2 measure by The FAST-1 compression meter provides a direct measure of fabric thickness at 2 gf/cm 2 (196 Pa) and 100 gf/cm (9.81 kPa). The FAST-2 bending meter provides a direct measure of fabric bending length in either the wale or course direction. Bending rigidity is calculated from the bending length and fabric mass per unit area. The FAST-3 Extension meter provides a direct measure of fabric extension under selected loads with wale and course directions. Shear rigidity is using extension on the bias at 5 gf/cm. Extensibility using measure of fabric extension under selected loads at 100 gf/cm with wale and course directions by KES FB-Auto system because the fabric speciments were every hightly extension with loading at E100 (100 gf/cm) from FAST Extension meter. KES FB-Auto determind the strain at 100 gf/cm and samples are clamped between 2 jaws with an effective test area of 5 cm x 5 cm. Simulation method The OptiTex software simulate the model of human body by input parameter of the model which determind the model medium size from European standard size 38 with 88 cm. bust circumference. The figure 1 illustrates the pattern construction for aerobic sportswear of ladies which reduced all of the size measurements 10% and designing 2D pattern from computer-aided program shows in the figure 1(a) and the figure 1(b) illustrates 3D simulation of human body surface for visual model.
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Figure 1. Pattern construction for aerobic sportswear: (a) 2D pattern construction, and (b) 3D pattern contour on model and setting measuring points for measuring pressure.
Evalulation method PicoPress used to measure the pressure the relation between time and pressure (mmHg) by setting the important parts on the body for measuring which have risked or the highly extension when covering with rigid mannequin. In figure 1(b), it could been seen that the critical points pressure on the visual mannequin had been measured by PicoPress pressure measurement system; however, these pressure results in the right side could be resembling the left side values as well.
3. Results and discussion The result of stretch fabrics properties could input parameters from Optitex simulator software had been used to determine the tension map on the virtual mannequin are as follows: The figure 2 shows the results of mechanical properties which were measured by FAST system. The value of extensibility marked (20.6%*) in figure 2 mean the tested fabric had very high extensibility due to the limitation of equipment measurement performance which could only measure 20.6%. Whereas, we use to simulate the value of tensile properties obtained by using the KES-FB system.
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Figure 2. FAST system control chart. (a) 65% PA, 35% Elastane and (b) 38% Outlast, 52% PES, 10% Spendex
The results of stretch fabric properties as shown in the Table 1 illustrated the parameters and functions of fabric editor from OptiTex. The editor function would be used to convert fabric physical attributes from FAST parameter to OptiTex parameter in oder to evaluate the tension of clothing when draping with the 3D model. Table 1. Elastic knitted properties from FAST system convert parameter to OptiTex parameter.
Parameter of fabric Bending X (Wale) Y (Coures) Stretch X (Wale) Y (Course) Shear Friction Surface Thickness Weight
65% PA, 35% Elastane FAST OptiTex 2.70 µN.m 245 dyn.cm 2.20 µN.m 31.61 % 121.68 g/cm 21.84 % 176.11 g/cm 25.40 N/m 762 dyn.cm 0.19 0.19 0.05 mm. 0.005 cm. 2 2 183 g/m 183 g/m
38% Outlast, 52% PES, 10% Spendex FAST OptiTex 1.60 µN.m 230 dyn.cm 3.00 µN.m 63.60 % 60.47 g/cm 38.89 % 98.89 g/cm 17.80 N/m 534 dyn*cm 0.27 0.27 0.286 mm. 0.0286 cm. 2 2 151 g/m 151 g/m
The figure 3, results from these 3D simulation had shown maximum tension value at the upper right corner of figure as well as tension gradient map of the stretch fabrics. In figure 3(a) 65% PA, 35% Elastane clothing had given higher tension value of 26.98 fg/cm more than 15.00 fg/cm maximum tension value of 38% Outlast, 52% PES and 10% Spandex clothing illustrated in figure 3(b). After observing 3D tesion gradient map, the colour distribution value on clothing from figure 3(a) and 3(b) are quite similar. In fact, the red areas in both figures had show differences in term of tension value. Besides, critical points should be determined in order to find out extension values of clothing from eight given points on the 3D simulated model.
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(b) Figure 3. 3D simulation tension map gradient. (a) 65% PA, 35% Elastane and (b) 38% Outlast, 52% PES, 10% Spendex
Tension value of two types of stretch fabrics at 8 different points of the body as shown in figure 1(b) had been compared in the figure 4. The values of tension in the figure 4(a) are evaluated by OptiTex software. The tension values of 65% PA, 35% Elastane fabric are approximately 46.30% higher than 38% Outlast, 52% PES and 10% Spandex fabric. At specific point 1 and 2 of shoulder positions in the figure 4(a), low values of tension have been illustrated. In the figure 4(b), pressure volume graph shows how PicoPress is used to determine pressure values from eight specific points on two different types of clothing worn on the rigid mannequin. Referring from the pressure testing, the results show that the value of pressure from fabric 65% PA, 35% Elastane are higher than the fabric 38% Outlast, 52% PES and 10% Spendex. Located at the back of the waist, specific point 7 shows the lowest value of pressure due to the fact that surface of rigid mannequin and the prototype had air gaps. Obviously, the third point at bust position had respectively shown the highest tension value and pressure value of 26.98 fg/cm and 9 mmHg measuring on fabric 65%PA, 35% Elastane clothing.
The Tension of stretch fabrics
Tension (fg/cm)
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PA65%,E35%
26.98
25
23.33 19.84
18.77
20 15
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17.58
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14.97 11.84
9.27
8.65
10 5
Outlast
11.39
11.55
8.56
3.69 2.64
0 Point1
Point2
Point3
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Point5
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The Pressure of stretch fabrics Pressure (mmHg)
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PA65%,E35%
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Outlast
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4 3 2
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(b) Figure 4. Comparison the value of tension and pressure between two stretch fabrics. (a) 8 critical points in the tension graph and (b) 8 critical points in the pressure graph.
4. CONCLUSIONS The results of the simulation has shown on the pattern construction 3D and the virtual mannequin that evaluated amend the tension map gradient results. The colour of tension map when simulated the distribution of 2 types of stretch fabrics had shared similar gradients. However, the results of the value of tension were different by the value of extensibility. The values of fabric elasticity in wale and course direction have an influence on values of tension and the value of the pressure. Obviously, the results of tension simulated by OptiTex were compared with the pressure of prototypes worn by rigid mannequin measured by PicoPress pressure tester. The extensibility values of stretch fabric from 65% PA, 35% Elastane of 31.61 % in wale direction and 21.84 % in course direction. Whereas, tension value of 26.98 fg/cm and pressure value of 9 mmHg at the bust point have no sense of discomfort in 2 the lower garment pressure range (0 – 15 gf/cm or 0 - 11.03 mmHg) accounting for garment pressure and comfort sensations. This could be concluded that the lower the extensibility value is, the higher pressure and tension will be and vice versa. It is certain that the extensibility of fabric tension could be evaluated by OpiTitex to adjusted in accordance to the pattern design suitable for tight-fitting clothing.
ACKNOWLEDGEMENTS The authors would like to extend sincere appreciation to the Research and Innovation Centre for Design and Clothing Science, Faculty of Mechanical Engineering, University of Maribor and Department of Clothing, Faculty of Textile Engineering, Technical University of Liberec and This work was supported by “SGS 21147”. as well as Dr. Danijela Klemenčič from LISCA company in Slovenia.
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