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.     

Effect of input tension of inlay yarn on the characteristics of knitted circular stretch fabrics and pressure generation

Stretch fabrics are used in manufacturing pressure garments to exert pressure over specific body parts in medical conditions like venous and lymphatic disorders, scar management, and bone and muscle injuries. The amount of therapeutic pressure required in each medical condition is different; therefore, there is a need to engineer the stretch properties of garments to match the requirements in each case. Limited information is available on the relationship between fabric properties and the pressure generated on the body. In this paper, an attempt has been made to study the effect of inlay yarn pre-tension at the time of manufacturing of stretch fabrics on the pressure generated by the garments. Results show that change in inlay pre-tension significantly changes the structural characteristics of the fabric but the load elongation behavior remains unchanged up to 100% extension. Pressure exerted on rigid cylindrical tubes increases with reduction factor of the fabric tube and the curvature of the cylinder.     

泡泡袖袖山褶皱凸起量的影响因素

探讨面料性能和袖山剪开量对泡泡袖造型效果的影响。采用5种性能迥异的面料,分别测量出其厚度、悬垂性、面密度、硬挺度等物理性能。结构设计中,在原型袖袖山处加放不同的参数,绘制泡泡袖样板;以袖山褶皱凸起量为主要因素,测量相关数据,并分析得出结论：当袖山剪开量偏小和中等时,面料的厚度和面密度对褶皱凸起量影响最大;当袖山剪开量偏大时,面料悬垂率越大,褶皱凸起量越小;面料性能一定时,褶皱凸起量的大小随着袖山剪开量的增大而增大。     

面料物理性能与袖山造型的相关性

选用13种常见面料并采用同一样板制作袖子,请专业人员对袖山造型好坏进行评分,然后借助相关分析及多元逐步回归分析研究面料物理性能与袖山造型间的关系。研究结果表明:在面料的规格参数中厚度与袖山造型关系最密切;在面料FAST风格参数中,延伸性及压缩性与造型的关系较密切,呈正相关关系,且延伸性中经向延伸性与造型效果的相关系数均大于纬向延伸性,其中负荷为0.98 N/cm下的经向延伸性与袖山造型的相关性最强;而弯曲性与袖山造型的关系很微弱。     

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.     

Simulation of a textile sleeve on a manikin arm undergoing elbow flexion: effect of arm-sleeve friction

The effect of friction on the interaction between a protective fabric sleeve and a manikin arm undergoing elbow flexion has been investigated both numerically and experimentally. The experimental studies used a cylindrical Kevlar sleeve on the right arm of a Hybrid III crash-test dummy. A load frame was used to produce elbow flexion and to measure the force required to produce that motion. Friction was varied by performing the elbow flexion task with and without a tight-fitting white knit polyester undergarment, and friction coefficients were determined experimentally. Corresponding numerical simulations using LS-DYNA were also performed, with the textile sleeve represented by orthotropic shell elements with geometric non-linearity based on experimental literature data. The results show that the presence of the Kevlar sleeve significantly increases the force required to execute elbow flexion, but that the addition of the friction-reducing undergarment reduces the flexion force generated by the Kevlar sleeve. Furthermore, this behavior can be effectively captured by the numerical simulation. These results demonstrate the possibility of direct simulation of the mechanical burden generated by protective clothing, which could lead to computational design of protective garments with improved comfort, and reduced reliance on human subject testing.     

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.     

对抗微重力环境下肌肉骨骼废用性病变的压力服装研究进展

针对航天员在微重力环境下的肌肉骨骼去重力性适应问题，以人体生物力学与服装功效学为研究背景，介绍了对抗微重力环境的压力服装的研究现状，分析了空间站现用压力服装和文献报道中的原型服装的对抗机制和结构功效特点，总结并完善现有评价方法。研究认为：该类压力服装存在重力加载量不足、性能测试单一的问题，应深入优化纺织成形工艺，探究服装力学性能与人体所需载荷的关系，结合多学科技术，全面评价服装加载功能性、穿着舒适性和人体生理适应性；研发持久稳定、透湿舒适的新型材料，提高评价方法的智能化和准确性以及将该航空压力服装技术转化为卧床患者康复措施是未来的发展方向。     

衣袖的结构设计及其运动机能性

以衣袖结构设计作为切入点,追求人体装饰美及运动舒适性两者完美统一的宗旨,阐述了衣袖的外观造型与运动功能的关系,并提出了解决措施。     

经编全成形脖套的结构设计与工艺实现

针对目前脖套结构单一,裁剪缝制加工工序多且有裁剪损耗等问题,在分析研究人体头颈部位尺寸数据的基础上,结合经编全成形原理进行全成形脖套款式结构设计与开发。首先确定基础纸样结构,在纸样上进行穿戴部位设计与结构分区,对于口鼻部位进行一体成形的双层织造结构开发,通过贾卡变化组织定位设计实现双层结构局部开口;之后在经编针织物CAD系统中进行贾卡组织设计,建立工艺模板并进行织物结构仿真;最后应用Style 3D软件进行经编全成形脖套的三维建模与虚拟展示。研究结果表明,一体成形的双层结构可通过贾卡变化组织实现,通过经编全成形织物的二维仿真与三维虚拟展示可快速预览开发织物的穿戴效果,为实现经编全成形新品的快速开发提供有效途径。     

Study on heat transmission through multilayer clothing assemblies under different convective modes

The present work reports a detailed study on dry thermal resistance of multilayered clothing assemblies under different modes of heat transmission (i.e. non-convective mode, natural convection and forced convection). A series of multilayered fabric assemblies have been created with different combinations of fabric layers (like plain woven, nonwoven wadding, warp-knitted spacer fabric, weft-knitted breathable coated and weft-knitted aluminium coated) and air gaps of different thicknesses between fabric layers. Significant impacts of thickness of air gaps and mode of heat transmission on thermal resistance of multilayered clothing assemblies have been observed. The thermal resistance of the fabric assemblies increases with the increase in the thickness of air gap in between fabric layers. The thermal resistance of all the fabric assemblies at any given air layer thickness is highest under non-convective mode of heat transmission, followed by natural convection mode and the forced convection mode shows least thermal resistance. Incorporation of coated fabric in the outer layer reduces the effect of forced convection. ANOVA has been prepared and F value has been calculated to find the effect of modes of convection, type of fabric and thickness of air layer on thermal transmission properties. The results obtained from this detailed study will help in designing multilayered clothing assemblies suitable for different climatic conditions.     

Study on interface pressure generated by a bandage using in vitro pressure measurement system

This paper aims to identify and analyze various factors responsible for the variations in the interface pressure exerted by compression bandages during compression treatment. Some of the major factors, i.e. the applied force, the limb circumference, and the numbers of bandage layers wrapped, were chosen to analyze their impacts on the initial interface pressure and also on the interface pressure profile generated by compression bandages over time during static mode of the mannequin limb. The testing under static mode was done using a leg-segment prototype, which allows continuous online measurement of interface pressure exerted by the bandage over mannequin surface. The interface pressure variations under dynamic mode of the mannequin limb was also investigated using another dynamic leg-segment prototype which simulates the dynamic behavior of the human limb i.e. walking, jogging, running, etc. The investigation of stress relaxation and fatigue behavior of the bandage was examined to find their impacts on the bandage performance under static and dynamic conditions. The result of an N-way analysis of variance shows that the applied force and number of layers significantly affect the interface pressure drop over time. The interface pressure drop under dynamic mode is faster and higher than the static mode. The study of relaxation and fatigue behavior of the bandage helps in evaluating the bandage behavior during compression treatment.     

消防服上装结构分析和调整

 本研究从目前消防战斗服上装的结构参数入手分析其结构特点,结合消防服的静态和动态穿着效果,探讨其在结构方面存在的问题。依据三维测量所得的人体动态变形情况和对消防服的运动功能性和防护性要求,对衣身、衣袖结构提出改进方案,具体包括：减少前后袖窿差、抬高袖窿线、增加袖底插片宽度以及在后袖缝增设褶裥等。按照改进方案进行样衣试制并进行穿着对比,实验表明采用结构补偿方法能够使消防服上装的遮蔽防护性能得到明显改善。     

闪火中防护服装的形变及其影响因素

防火服在火焰中的收缩形变会影响其热防护性能并制约人体的肢体运动。本文提出用捺印的方法,通过燃烧假人闪火燃烧试验研究防火服各部位形变量的分布规律,探究形变差异的原因及影响因素,对比分析服装形变与假人皮肤表面烧伤程度的关系。结果显示,燃烧试验后防火服在四肢和背部发生了显著收缩形变,热流量、衣下空气层等是主要影响因素。着装姿势越复杂、闪火持续时间越长,服装越宽松,服装面料的面密度越大,服装形变越显著。服装形变显著的对应部位衣下皮肤的烧伤也越严重。     

基于三角模糊数的汉服袖型感性评价北大核心CSCD

为探究消费者对汉服袖型的感性认知,帮助服装设计师更准确地把握消费者心理,文章选取具有代表性的8款汉服袖型,采用语意差异法收集袖型样本在6对感性形容词汇上的感性评价,将其用三角模糊数的形式进行表征,并对模糊评价结果的准确性进行检验。为得到各汉服袖型较为精确的感性评价,文章对三角模糊数进行贴近度分析,并将贴近度的结果作为依据,运用系统聚类的方法将汉服袖型分为4类。研究表明:各汉服袖型因袖宽大小、袖缘线条形状、袖长、袖口形状的不同,感性评价存在一定差异,且最终感性评价结果符合客观认知。经验证可知,利用三角模糊数能够较准确地对汉服袖型进行感性评价。     

藏族服装袖型结构在现代服装中的融合应用

以藏族袍服的袖型结构为主要研究对象,分析了藏民袍服袖型的结构特点,并将其融合于现代服装袖型的结构设计理念中进行设计,为现代服装的袖型及肩部造型结构设计提供更多的方法。运用服装结构学、服装设计学知识,合理将藏族服饰结构特征融入到现代服装结构设计中,为现代服装及民族文化服饰的传承与发展提供设计方向,弘扬传统民族服饰文化。     

牛仔面料性能对泡泡袖成型的影响

测量了7种不同牛仔面料的性能参数和由其制成的泡泡袖的各项性能参数,并用数理统计的方法研究了牛仔面料性能对泡泡袖收褶量大小和泡泡袖整体造型的影响。研究结果表明,泡泡袖的收褶量大小及其成衣整体造型受牛仔面料厚度的影响最大,其次是面料的悬垂性和织纹密度,因此用不同的牛仔面料制作泡泡袖时,设计袖型收褶量和抬高量应以厚度为第一考虑因素,厚度对袖子的泡泡效果,袖身的挺括度都呈正向影响。其次考虑织物的悬垂性和织纹密度。     

The influence of two bar warp-knitted structure on the fabric tensile stress relaxation Part I: (reverse locknit,sharkskin, queens’ cord)

Time-dependent mechanical behavior of textiles has particular importance. One of such behaviors is the stress relaxation. If a fabric is under tension over a period of time, some of the stresses in it will be relieved. During the manufacture and application of clothing and footwear, materials experience various long-lasting deformations, and relaxation process in materials arises. For example, if medical pressure garments such as compression stockings are under tension over a long period of time, some of their stresses will be relieved, with a consequent reduction in the skin and garment interfacial pressure. Thus, with theoretical and experimental study of the factors affecting stress relaxation, the ability to design and produce appropriate clothes will be increased. The aim of this study was to investigate the effect of fabric structure on the stress relaxation of two bar warp-knitted fabrics (reverse locknit, sharkskin, queens’ cord), as well as to find the effect of strain value and loading direction on the stress relaxation of the fabrics. The results reveal that the fabric structure, strain, and loading direction are important factors affecting the stress and stress relaxation percent of the fabrics. By increasing the strain and the length of underlap in the back guide bar, stress will be increased, but stress relaxation percent will be decreased. Also, stress relaxation percent in wale direction is more than course direction for reverse locknit and sharkskin3, but this is reversed for sharkskin4 and queens’ cord. Finally, among the mechanical models used to describe the stress relaxation behavior of the fabrics, three-component Maxwell’s model with parallel-connect nonlinear spring showed the best agreement with the experimental relaxation curve of the analyzed fabrics.     

全成形针织服装三维款式向二维样板转化方法

为进一步了解全成形针织服装的编织原理,开发出更多不同造型的服装,从理论依据、数学模型以及转化流程3个方面探究了全成形针织服装三维款式向二维样板转化原理;从双层结构、三层结构以及四层结构3个方面研究了不同类型服装的三维款式向二维样板转化方法;以5种典型款式为例,运用上述方法在SDS-ONE APEX3系统和四针床电脑横机中进行了二维样板设计与编织实践。结果表明:三维款式向二维样板转化时,双层结构服装二维样板前后片需根据三维款式前后片是否等宽从左右侧缝或前后中心线处确定;三层结构服装二维样板需根据三维款式有无袖从后中袖窿分割或门襟侧缝处展开后确定;四层结构服装里外层衔接位置应位于领部、腰部等特殊部位。     

带织物层叠缠绕玻璃钢管的设计与缠绕成型

采用仿形织造方法织造带织物,并用该带织物层叠缠绕生产玻璃钢管道是一种新方法。在缠绕成型过程中,为了使管道的成型性良好,需要对缠绕角度、经纱长度、织物幅宽等进行设计,同时选择成型效果好的织物组织。试验结果表明:圆直管道预成型织物的缠绕角取决于织物幅宽、缠绕层数和管道直径;织物的经纱长度不等,按照一定的规律随缠绕层数的增加而增加;2/2斜纹组织织物的成型效果较好。