Three-Dimension Parametric Simulation of Knitted Fabric Based on the Twisted Loop Model

To enhance the realistic simulation effect of knitted fabric, a new three-dimension （3D） twisted loop model was proposed. This model was constructed by using Non-uniform Rational B-Spline （NURBS） surface. The control points of this surface were generated through rotating the cross-section along the center path of yarn. The cross-section of yarn was generated based on the two-level hexagonal ~lose packing model. Both of the center path and the cross-section were fitted by NURBS. With this twisted loop model, 3D parametric simulation of knitted fabric was realized in 3DS MAX by utilizing MAXScript and analyzing the relationships between structure parameters （including the wale-spacing, the course-spacing, the yarn diameter, .and the fabric thickness） and geometric model. The simulation of knitted fabric has 3D realistic twist effect dearly. Furthermore, the structure parameters and the twist parameters of fabric can be modified interactively.     

Investigation on the Dimensional Properties of Relaxed Plain Knitted Fabrics

A geometric model of relaxed plain-nitted fabric isproposed.A method based on the model for predictingthe loop length from the course spacing,wale spacing offabric and the diameter of yarn is deduced,as well as a computer program is developed to graphically represent the structures of plain knitted fabric with various struc-tural parameters.     

Study on Wet Permeability Models of Yarns and Knitted Fabrics

Water transport through the pore structure of the knitted fabric can occur only in place where the fiber-water surface attraction force is greater than the water weight in the capillary. To investigate wet permeability of the knitted yarn in the fabric, a liquid transport model is established. The main factors which have significant influences on the liquid transport have been analyzed. It is derived from the argument that the optimal design for the knitted fabric with quick sweat transport property can be obtained.     

纱线均匀度指标离散率及与织物外观质量的关系

本文根据离散率的定义,讨论了离散率的意义,由所假设的随机纱条的条件,推导了随机纱条的离散率公式和近似的计算式.并用18.2 tex(32°)普梳纯棉纱做了纱线均匀度与针织物和机织物外观质量之间的对照试验,且对实验结果进行了分析。     

基于AE技术和HHT的涤纶机织物拉伸断裂过程研究

为了获取与研究织物拉伸破坏模式的时频特征,通过改变织物组织结构和纬纱密度织造4种不同织物,在常规织物强力仪上利用自主搭建的声发射检测系统,分别采集对应织物拉伸破坏过程中产生的动态声频信息,利用Matlab软件运行基于HHT方法编译的程序对所采集信息进行信号分析与处理。分析结果表明:织物拉伸过程的AE信号曲线与拉伸载荷-位移曲线完全对应,所表征的结构相变化、纱线形变以及纱线断裂3个破坏模式可明显区分;4种织物结构相变化阶段特征频率相同,均为100Hz,且来自同一来源——经纬纱间正交摩擦,与织物组织、密度无关,表现在持续时间、幅值、能量等声发射信号参量上,结构相变化阶段与纱线强力利用系数大小有关。     

3D Simulation of Two-bar Warp-knitted Structures

In this study,3D computer modeling of simple warp-knitted structures is achieved based on 3D model of warp-knitted loops.Firstly, according to the studying on the geometric structure of warp-knitted loops, Gktepe's 3D solid yarn model is developed,and the dimensions of the warp-knitted loops are obtained;then 3D models of stitch defined by eleven given points and in-lay defined by five given points are built with the method of Non-Uniform Rational B-Spline (NURBS) curves and surfaces.Secondly, according to...     

Tensile Property of Bi-axial Warp Knitted Structure

The tensile property of bi-axial warp knitted fabrics is tested and compared with that of the plain weave fabric. The results show that there are obvious differences between the tensile property of a bi-axial warp knitted fabric and that of a plain weave fabric. The former can give fuller play to the property of a high modulus yarn than the latter. The tensile strength of a bi-axial warp knitted fabric is linear with the number of yarns in the direction of force.     

The Mechanical Behaviour of Rubber Hose Reinforced with Warp Knitted Fabric

IntroductionBendable pipe is an indispensable non-metallic part ofautomobiles , which is used to transport cooling liquid,hotair and oil media . Auto radiator hose is a bendable rubberhose connecting the water tank ,radiator and engine ,andit is used to transport cooling liquid . Smooth surface ,easy assemblage , high inside pressure bearing capacity ,low radial direction expansion ratio are required. As far asthe mech-anical perfor mance of auto radiator hose isconcerned , ISO4081requires t…     

基于VRML-Java的虚拟现实技术在可视化装配中的应用

为实现建立在开放技术标准之上的可视化装配系统，本文对基于VRML－Java的虚拟现实技术在工程设计领域的应用进行了研究，提出了一种新型的Web环境下3D交互仿真结构，3D模型下载到客户端显示，复杂的运算和仿在服务器上进行，从而实现服务器端装配模型和客户端显示模型的分离，在此基础之上可以完成VRML场景的动态生成，装配控制、碰撞检测以及装配过程的动画回放等功能，该结构不仅可用于网络环境下的可视化装配，也适合于其他领域基于Web的科学可视化。     

基于分布式虚拟现实的高超声速飞行器仿真系统

针对高超声速飞行器X--38,基于Java和虚拟现实建模语言(VRML),提出并具体实现了一个基于客户机/服务器模型的分布式虚拟仿真系统,重点讨论了其中的三维场景建立与动作事件建模、分布式网络结构设计与数据库管理、场景接口实现等关键技术.虚拟仿真系统实际运行效果良好.该系统具有良好的可移植性和可扩展性,易于大规模部署,也可方便地进行二次开发.     

Characterization of Deformations of Multiaxial Warp Knitted Fabrics during Forming Process

The typical structure(with four inserting yarn systems) of multi-axial warp knitted fabrics shows unsatisfactory conformability according to hemisphere pressing experi-ments.The structure containing only two bias inserting yarn systems(TBMWK fabric),however,proves to possess good conformability.This paper characterized in detail the forming behavior of TBMWK fabric.It was found that the two bias inserting yarn systems tend to gather always along the weft direction,and the angles between them along this direction are basically linear to the perpendicular distances from the measured points to the longitudinal axis of the hemisphere.And the     

基于几何模型的纬编提花织物结构计算机辅助设计

通过对构成纬编提花针织物的基本线圈单元进行几何结构分析,建立几何模型,开发了一套纬编提花针织物计算机辅助设计系统。利用该系统,通过输入花型信息及圈高、圈宽、纱线直径等参数,不仅能以图形方式直观地显示针织物的线圈结构形态,还能计算线圈长度等织物结构参数。     

Effect of Knitting Process on Elastic Property of Polyethylene Terephthalate (PET)/Polybutylene Terephthalate (PBT) Warp Knitted Fabric

This study investigated the elastic elongation and elastic recovery of the elastic warp knitted fabric made of polyethylene terephthalate( PET) and polybutylene terephthalate( PBT)filament. The effect of knitting parameter on the elasticity of PBT /PET warp knitted fabric was analyzed. The increase of drawing density( from 16 to 26 courses per centimeter( CPC)) on machine resulted in the decrease of elongation at the weft direction. But,the elongation at the warp direction fluctuated as drawing density increasing. The yarn run-in speed influenced the elongation of PET /PBT warp knitted fabric as well. When the yarn run-in speed of GB1( front bar) was kept a constant,the increase of GB2( back bar) yarn run-in speed caused the gradual enhancement of the elastic elongation at the warp direction,but the different trends of the elastic elongation at the weft direction. When yarn run-in speed of GB2 was kept a constant,the increase of GB1 yarn run-in speed enlarged the elastic warp elongation from 104.16 to 124.97 mm,while the weft elongation decreased from 110.34 to 98.03 mm.Eventually yarn run-in speeds of GB1 and GB2 were retained at1 360 and 1 170 mm / rack respectively under 20 CPC drawing density. It could not only balance the two directions of elongation but also reach the highest elongation at both directions( 126. 32 and115.88 mm) under 100 N tension. These results provide a better understanding of characteristics of PET / PBT warp knitted fabric,and its elastic elongation and recovery behavior for development and effective applications.     

BP Neural Network Based on Microwave Method for Measuring the Moisture Content of Textile

The moisture content of yarn and fabric is an important factor in textiles industry.A novel microwave method used for material moisture content measurements is described in this paper.It can estimate the moisture content of the yarn roll with a standard deviation of 1.58% in the range of 0% to 90.00%.According to the actual size of the yarn,the yarn roll simulation model is established.The microwave attenuation variations arising from the changes in the conductivity and dielectric constant of the wet cone yarn from1.8 GHz to 5.0 GHz frequency are obtained by ultra-wideband antenna.The measured data are analyzed using the BP neural network.The result shows that it is a non-contact and online method to solve the moisture content of the yarn in the wide moisture content range.     

Study on Misplating Problems of Composed of Wool and Lycra Plated Knitted Fabrics

By a great deal of experiments,the misplating problemsof plated knitted fabrics composed of wool and Lycra arediscussed and analyzed.The factors affecting the mis-plating problems on manually operated flat knitting ma-chine include the construction and adjustment of a plat-ing feeder,wool yarn count,feeding tension,takedowntension and the ground fabric structures.Some usefulresults can be derived from these works.     

基于均匀化理论的针织物拉伸形变有限元模拟

针对针织物形变规律问题,以纬平针织物为研究对象,通过均匀化理论建立宏细观线弹性数学模型,确定针织物的周期性边界条件及载荷边界条件,采用数值模拟方法对织物等效弹性刚度求解,并结合有限元方法计算两种纬平针织物在双向拉伸下的应力应变响应值。与试验数据相比,当织物拉伸的应变小于5%时,基于均匀化理论的方法可准确模拟形变的应力应变关系,而当应变超过15%时,该模拟方法存在一定误差,但误差均可控制在9.7%之内。     

纬编针织物外观模拟纹理映射技术研究

为更好地展示针织物的着装效果,针对针织纹理图案结构性强的特点,将网格分割算法同两步纹理映射算法相结合.首先利用模型三角片的切向量场将其进行区域划分；然后在两步纹理映射的基础上,提出了将区域的包围盒作为中介面进行纹理映射的算法；最后利用拼接面片纹理技术对纹理接缝区域进行平滑处理,实现纹理的无缝拼接.试验结果表明,该算法既保证了纹理图案在三维模型表面的连续感,又能满足纹理走向符合物体表面形状的要求.     

Wet Permeability and Moisture Vapor Transmission Characteristics of Soybean Knitted Fabrics

Wet permeability of fibrous assembly is mainly influenced by the properties of liquid and the configurations of the fiber which consist of diameter of fiber, twist angle and fiber alignment in a yarn. It can be seen from experimental results that the knitted fabric made of soybean (SB) fiber has good properties both in wet permeability and vapor transmission so that the knitting technology and fabric characteristics can be improved.     

基于倾斜矫正算法的针织物图像研究

倾斜的针织物图像在图像处理前需要对其倾斜进行矫正预处理,但由于针织物图像的特殊性,使其不能采用机织物等倾斜图像的矫正方法。针对这一难题,利用一维傅里叶变换求针织物纵密频谱和横密频谱。计算,然后根据各自频谱的峰值特性进行自动旋转倾斜矫正。给出了算法细节,同时还得到针织物的拉密度。实际研究表明,所采用的方法在针织物行业里尚属独有,运算量小,实时性高,具有很大的普适性,非常适合于在针织物的图像检测领域推广,具有广泛的实际应用价值。     

Research on the Loop Deformation of Flat Silk Knitted Fabric Made from Parallel Spun Silk/ramie Core Yarn

This paper analyzes the causes of loop deformation of flat silk knitted fabric made from parallel spun silk/ramie core yarn. Through the measurement and analysis on the loop deformation of various samples, it is concluded that the problem herein mentioned would be improved to a certain extent by changing the fabric density or mixknitting from yarn with different direction of twist.