Finite element modelling the mechanical performance of pressure garments produced from elastic weft knitted fabrics

Compression garments mainly produced from elastic knitted fabrics have attracted many attentions due to their medical care performances. Components’ characteristics of the pressure garments such as yarn and fabric structure affect significantly the pressure applied on the human body. In this paper, it is aimed to simulate the effect of yarn’s mechanical properties as well as fabric structure on mechanical performance of the compression garment. For this purpose, a precise geometrical model for fabric structure is needed by which the pressure applied to the body could be predicted. Accordingly, double jersey knitted fabrics containing elastane weft yarns were produced on an electronic flat knitting machine and the fabric tensile properties were measured in course direction. Using equations governing the fabric structural unit-cell, a real geometric model was created in a finite element software environment. Considering the linear visco-elastic properties for elastane weft yarn, stress-strain curve was extracted. The results obtained from numerical simulation were compared with the experimental data in order to validate the proposed geometrical model. The findings demonstrate a good agreement between experimental and simulation results.     

Modeling the effect of elastane linear density,fabric thread density,and weave float on the stretch,recovery, and compression properties of bi-stretch woven fabrics for compression garments

The aim of this study was to investigate the effect of elastane linear density, thread density, and weave float on the stretch, recovery, and compression properties of bi-stretch woven fabrics for compression garments. Fabric samples were produced using elastane core-spun cotton yarns both in the warp and weft. The elastane linear density, fabric thread density, and weave float size were used as input variables while fabric contraction, subgarment pressure, fabric stretch, and recovery were taken as response variables. Two different elastane linear densities, i.e. 44 and 78 dtex, two different thread densities, and three different weave designs, i.e. 1/1 plain, 2/2 z-twill, and 3/3 z-twill were used. The results of fabric samples were analyzed in Minitab statistical software. The coefficients of determinations (R-sq values) of the regression equations showed good prediction ability of the developed statistical models. The findings of the study may be helpful in deciding appropriate manufacturing specifications of bi-stretch fabrics to attain specific stretch, recovery, and compression properties.     

Development of woven stretch fabrics and analysis on handle,stretch, and pressure comfort

Twelve stretchable fabrics are woven in two sets with one set in 50^s and 60^s 100% cotton in warp and 40^s, 50^s, and 60^s cotton core spun lycra yarn in weft and another set with 2/75 and 2/120?Nm silk in warp with 40^s, 50^s, and 60^s cotton core spun lycra yarn in weft. Hundred percent cotton sari blouse materials commercially available in the market are also included for a comparative study of pressure distribution between cotton core spun lycra fabrics and cotton blouse materials. The influence of fabric specification on total hand value (THV), stretch properties, and pressure comfort is analyzed. The effects of body shape and fabric mechanical properties on garment pressure are also analyzed. The results indicated that the finer counts of cotton core spun lycra woven with cotton and silk to elasticize fabrics provided improved hand feel, stretch, and pressure comfort values. The average pressure value of the samples at the major pressure points with the cotton/cotton core spun lycra samples and silk/cotton core spun lycra samples is lower than 100% cotton samples’ fabric physical properties, stretch properties, mechanical properties, and THV significantly influenced the pressure distribution and comfort of garments.     

毛粗纺弹性纬纱加工参数对织物性能的影响

文章介绍了毛粗纺氨纶包芯纱的捻系数和氨纶牵伸倍数对粗纺弹力织物强伸性和弹性的影响规律,并得出了适合毛粗纺弹力织物性能的毛/氨包芯纱工艺参数.     

Modeling the mechanical and compression properties of polyamide/elastane knitted fabrics used in compression sportswear

A compression sportswear fabric should have excellent stretch and recovery properties in order to improve the performance of the sportsman. The objective of this study was to investigate the effect of elastane linear density and loop length on the stretch, recovery, and compression properties of the weft-knitted polyamide/elastane (PA/EL) stretchable fabrics used in sportswear. Two different tests were performed to study the stretch and recovery properties of the fabric 1st: under low power force and 2nd: cyclic loading under high tension force. Kikuhime pressure sensor was used to measure the pressure generated by different PA/EL knitted sample garment sleeves. It was found that with the increase in elastane linear density there is an increase in fabric course density, areal density, recovery percentage, and compression, and fabric stretch percentage and elongation percentage decreased in both course and wale direction. The results of fabric samples were analyzed in Minitab statistical software. The coefficients of determinations (R² values) of the regression equations showed good prediction ability of the developed statistical models.     

3—THE FINITE-DEFORMATION THEORY OF PLAIN-WEAVE FABRICS PART I: THE BIAXIAL-DEFORMATION THEORY

Theories of the biaxial tensile properties, the uniaxial tensile properties, and the shear-deformation properties of plain-weave fabrics are presented in a general form, a simplified stereo-model of the structure of plain-weave fabrics being used throughout these theories.

In the first part of this series, the biaxial tensile-deformation theory is presented with the aid of the model, and the forces required to stretch the fabric along the warp and weft directions at the same time are theoretically calculated from the properties of yarns and from the structure of the fabrics. In this biaxial theory, both warp and weft yarns are assumed to be perfectly flexible, and the forces caused by yarn-bending are ignored. The compressibility of the yarn under the action of a lateral compressive force is also introduced into the theory, and it is shown that the compressive properties of yarns have a great influence on the tensile properties of the fabrics.     

医疗袜用弹力管状针织物的开发与性能测试

为解决医疗袜穿着适配性存在的局部截面压力不均匀问题,编织3种弹力管状针织物,每种织物选用3种规格衬垫纱线,针对脚踝、小腿、大腿3个不同部位进行袜机参数的4因素3水平L₉(3⁴)的正交试验设计;对织物进行截面周长、织物克质量、密度、厚度及接触压力测试。研究发现,同一织物,在相同测试部位,压力值随腿模型号增大而变大;不同衬垫纱织物,衬垫纱越粗,压力值越大;袜机编织参数相同,围度上由两种组织编织的弹力管状织物的压力值大于单一组织的织物。     

The dimensional and mechanical properties of wool/polyester fabrics made from vortex and ring-spun yarns

Fabric woven from wool/polyester (PES) Murata vortex spun (MVS) blend yarn is a commercially viable proposition particularly on the basis of advantageous wear-resistant properties, compared with fabric made from traditional worsted ring-spun yarn. However, in some early industrial trials with fabric made from 45/55-blend wool/PES MVS yarn, significantly greater relaxation shrinkage was found relative to comparable worsted ring-spun fabric. It was noted at the time that the amount of relaxation shrinkage in MVS fabric could be reduced to a large extent by using steamed MVS yarn.

In this study, the extent of variations in the dimensional and mechanical properties of fabric samples woven from a combination of steamed and unsteamed MVS yarn and equivalent worsted ring-spun yarn is examined. In general, greater hygral expansion and relaxation shrinkage were found in loom-state fabrics made from unsteamed MVS yarns, whereas the fabric made from steamed MVS and ring-spun yarns gave relatively low levels of relaxation shrinkage and hygral expansion. Permanent setting of fabrics, by pressure steaming, was found to be more effective than yarn pre-steaming in reducing relaxation shrinkage levels of fabrics made from unsteamed MVS yarn. After pressure steaming, all fabrics showed similar levels of relaxation shrinkage and hygral expansion.

Permanent setting of the fabrics, by pressure steaming, resulted in similar levels of relaxation shrinkage and hygral expansion, irrespective of the yarn production method; relaxation shrinkage fell to around 1% and hygral expansion increased by about 1%, relative to the loom-state samples. MVS fabrics were relatively heavier and fuller and had a firmer handle than the worsted ring-spun fabrics, reflecting the greater fabric weight, thickness and shear rigidity measured on these fabrics. These attributes are associated with different structures of the worsted ring-spun and MVS yarns used to make the fabrics.     

Physical properties of ring,compact, and air vortex yarns made of PTT/wool/modal and wearing comfort of their knitted fabrics for high emotional garments

This study examined the physical properties of PTT/wool/modal yarns according to the yarn structure and the wearing comfort of their knitted fabrics for high emotional garments. For this purpose, the air-vortex, compact, and ring yarns and their knitted fabrics were prepared to analyze the wear comfort according to the yarn structure and the possibility of applications of the PTT/wool/modal blend fibers to air-vortex yarn. The wicking and drying rates of the air-vortex yarn knitted fabrics were superior to those of the ring and compact yarns fabrics, and the heat-keeping capability of the air-vortex yarn knitted fabric was higher than those of the ring and compact yarns fabrics due to the low thermal conductivity and maximum heat flow rate. In addition, the pilling of the air-vortex yarn knitted fabric was less than those of the ring and compact ones due to the air-vortex yarn structure with parallel fibers in the core part and the periodical and fasciated twists on the sheath part of the yarns. The tactile hand of the air-vortex yarn knitted fabric was harsher than those of the ring and compact yarns knitted fabrics because of the low extensibility and compressibility, and the high bending and shear rigidities.     

Influence of stabilization and short-term relaxation to compression generated by stocking welt

Abstract

This research was carried out to investigate the influence of yarns and knitting parameters, stabilization, and relaxation processes on compression properties of knitted fabrics, used for stocking welt or other compression products. It is well-known that there is a high correlation between the mechanical properties of the fabric and its generated pressure. Also, it is proved that generated compression values decrease during the time they are being worn. In this research, it was found that course and wale density of knitted fabric, as well as tensile force values, increased after the stabilization process. Moreover, increases of linear density of core yarn (PU) of elastomeric yarn do not have direct linear influence to its generated tensile force. The results of short-term stress relaxation tests (300?sec) showed that the major alteration of the generated compression values appears during the first 100?sec period of relaxation process.     

弹性纱在高速织机上的加工

采用弹性纱制织的织物是对时装业的流行趋势,本文介绍了在剑杆织机和片梭织机上加工经纱或纬纱为弹性纱的织造方法,以及弹性纱的引纬方法和坯布卷绕方法。     

Thermophysiological comfort properties of selected knitted fabrics and design of T-shirts

Thermal comfort is one of the most important components of comfort which shows physiological, psychological, and physical harmony between human body and environment. The heat and moisture transfer capacity of fabric from skin to environment affects the thermal comfort of garments. The transfer capacity depends on the characteristic features of raw materials and fabric structural properties. In this study, it is aimed to determine the advantages of knitted fabric types, taking into account the environmental condition and activity level by measuring the thermal comfort properties such as air permeability, wicking, moisture management, thermal and water vapor resistances. Two knitted structures composed of tuck and float combinations and six raw materials were chosen for the fabrics produced. According to the measurement results, the polyester and cotton/Coolmax fabrics with float stitches have had good liquid moisture transport properties. Besides, high air permeability and low water vapor resistance have been obtained in viscose and Tencel LF fabrics with tuck stitches. On the basis of the results obtained in this investigation, and taking into consideration thermal behavior of human body, four women’s and five men’s T-shirts are designed. These T-shirt designs may be helpful for further approaches on the optimization of thermal comfort for sports activities in hot environment.     

Interface pressure generated by knitted fabrics of different direction,composition and number of layers in sport compression garments

The present study aimed to determine the effect of fabric direction, fabric composition and number of fabric layers on pressure generated by sport compression garments. Experimental fabric used in commercially available compression sport garments was chosen. Experimental fabric sleeves imitating a part of a pressure garment were assembled and placed on cylinders of different diameters, so that they provided different fabric direction, fabric composition of sleeve and number of layers in assemblies along the circumference of the cylinders. A Salzmann MST MK IV pressure-measuring device and Salzmann MST 2007 software were used to measure the interface pressure generated by the sleeves. It was established that different direction, fabric composition of sleeve and number of fabric layers in fabric assemblies influences the interface pressure.     

基于可调张力装置的芳纶织物交织阻力研究

为更加真实地模拟芳纶织物在受到冲击时产生的交织阻力变化情况,通过构建一个半经验模型来预测对于不同规格、不同预加张力情况下纱线交织阻力的数值,并设计了可调预加张力的纱线抽拔实验用夹具,分别以织物的经向宽度、纬向宽度和预加张力为变量对纱线进行抽拔实验.实验结果表明:对织物施加横向预加张力与纱线抽拔时的交织阻力呈正相关,预加...     

The effects of chitosan antimicrobial treatments on the physical and mechanical properties and wear performances of highly elastic fabrics used for burn scar management

As exerted pressures play a critical role on highly elastic fabrics on performances of pressure garments in burn scar management, they should also protect their physical and mechanical properties after chemical treatments. Samples were treated with chitosan to achieve antimicrobial property for further designs to help rehabilitation. In this study, the physical, mechanical properties and wear performances of chitosan treated highly elastic fabrics in comparison with untreated control samples were investigated. Results showed that a small significant decrease was observed for air permeability, bursting strength and drapeability while a small significant increase was observed for stiffness (CD, MD). The elasticity of the fabrics was protected during 90 days observation with time-dependent fabric growth analysis. The moisture regain of the fabric samples showed a small significant increase. Antimicrobial tests showed that all treated samples have a very good antimicrobial activity.     

Development and evaluation of dustless fabrics for medical applications

Dust-free fabrics and garments are essentially used in hospitals to maintain hygiene in operation theatres and also in various other industrial establishments, such as cleaning electronic chip manufacturing rooms. It is also needed for personal health care of allergy and asthma patients. In order to design a dust-free fabric, it is very important to study the characteristics of the textile materials that influence dust attraction. In this work, the dust particle size and its distribution on different types of fabrics with different fibre types have been studied making use of non-conventional instruments. As of today, there is no instrumental technique available for studying the dust concentration on textile substrates. Therefore, there is a need for developing an instrument that would measure dust particle size and their concentration on textile materials. A digital dust analyzer has been developed for this purpose. This instrument is calibrated by standard dust particles that have similar properties as that of atmospheric dust particles. The reference dust particle size falls in the range of 0.1–198 μ m. A set of fabrics were selected to study the effect of fabric properties towards dust attraction. The results revealed that lowest dust accumulation occurs on plain woven 100% polyester fabrics followed by polyester–cotton blends. The dust-less fabrics developed through different techniques such as polyurethane coating, silicone finishing and weaving of metallic filaments showed satisfactory improvement in their functional properties. Polyurethane coated fabrics give best results followed by silicone finish fabrics and metallic yarn woven fabrics. Based on the analysis and understanding of the results, some of the factors influencing the dust affinity of fabrics are established.     

Elastic Recovery and Performance of Denim Fabric Prepared by Cotton/Lycra Core Spun Yarns

ABSTRACT

Elastic performance coefficient (EPC) and recovery behavior of denim fabrics prepared with cotton/lycra core spun stretch yarns have been presented in this article. The denim fabrics are woven as broken twill weaves in an air-jet weaving machine by the insertion of core spun yarns (lycra filament in core, cotton fiber on sheath) as weft and using 100% cotton yarns as warp. The effect of linear density and stretch percentage of the core spun weft yarns on tensile and recovery behavior of denim fabric have been investigated by employing full factorial design of experiments. It has been observed that the tensile strength and EPC of fabric increase with decrease in linear density and stretch percentage of the core spun stretch yarn. The immediate elastic recovery and delayed elastic recovery increase with decrease in linear density and stretch percentage of the yarns.     

膨体弹力真丝的结构及性能

介绍了膨体弹力真丝的形成原理和机加工方法，并对膨体弹力真丝及其织物进行了性能测试。测试结果表明，膨体弹力真丝具有显著的弹性伸长量和回复量，良好的膨松性与卷曲性，其织物具有较强的膨松性与毛型感，与普通真丝织物相比，具有明显的弹性与韧性。     

试论基于服装的面料风格设计

围绕基于服装的纺织面料设计主题,探讨了服装与面料发展的互动关系,指出面料设计的理念要适应服装社会文化的进步,面料生产的技术要满足服装消费变革的需求。创新思维是面料进步的原动力,创造设计是服装面料成功的法宝。服装面料的创新与进步是服装创新与升级的最重要物质支撑,服装面料的进步加速了服装的流行和消费革命。同时,服装的变革进步也推进了面料的升级与进步。     

竹浆/棉混纺纱针织物的服用性能

以竹浆/棉混纺纱为研究对象,经圆纬机织造和后整理工艺制备出纬平针和双罗纹针织物,测试分析了织物的透气性、透湿性、芯吸性、吸湿快干性、悬垂性、刚柔性和表面摩擦性等服用性能。测试结果显示,竹浆/棉混纺纱针织产品具有良好的春夏季服用舒适性能。