基于计算机视觉技术的经编线圈结构仿真

该文根据线圈形态变化特征,运用非线性曲线方程对经编线圈结构进行数学建模,建立了三维经编线圈结构模型。基于计算机视觉技术对线圈模型进行光照处理和纹理结构合成,得到了经编线圈的光照模型及纹理映射模型,结合Visual C++和OpenGL三维图形处理技术,开发了仿真程序,实现了经编针织物三维仿真。由演示的效果图可以看出,经过光照及纹理处理后仿真结果与实际线圈结构十分相似,具有良好的立体真实感。     

贾卡经编针织物仿真方法研究

文章详细研究了经编针织物线圈结构的模型,在此基础上结合贾卡经编针织物的结构特点,提出了贾卡经编针织物的仿真方法,为贾卡经编针织物的计算机辅助花型设计与三维仿真提供了行之有效的方法.     

基于NURBS曲面的经编针织物三维模型

 为使经编针织物CAD系统具有更真实的模拟效果,给设计人员提供准确的工艺设计方案,使用NURBS曲线和曲面的方法建立经编针织物的三维结构模型,并利用保形保凸反算插值的方法,在基本型值点的基础上重构表示经编线圈曲线模型的控制多边形,精确地确定空间纱线的实际形态和位置,描绘出精确的空间曲线。借助于Visual C++和Open GL开发工具,在计算机上实现了经编针织物的三维仿真。由实现的基本经编针织物效果图可以知道,这种模型能达到较好的仿真效果。     

经编组织的三维仿真与动态实现

为了对经编针织物的结构特征和外观效果进行预测,通过分析普通经编针织物的线圈结构,对O Goktepe的三维实体纱线模型进行了改进,得出线圈三维结构尺寸。利用非均匀有理B样条（NURBS）曲线和曲面原理,建立经编组织成圈线圈和衬纬线圈的三维实体模型;运用这些三维线圈模型,结合经编组织的垫纱数码,实现各种形态线圈的自由连接;最后运用Visual C++和Open GL开发工具,将织物的光照和材质因素引入织物三维结构模型中,成功实现对单梳和双梳经编组织的三维模拟。     

轴向经编针织物的设计与仿真

为了解决轴向经编针织物计算机辅助设计方面的不足并且最终实现其快速设计,本文针对轴向经编针织物的CAD设计与仿真功能进行了研究。在深入了解轴向经编针织物生产工艺的基础上,采用实验的方法测量了织物结构的尺寸,建立了轴向经编针织物的CAD设计模型,其中包括地组织模型和铺纬组织模型;重点研究并建立了轴向经编针织物的纱线与线圈的二维仿真模型,以及玻璃纤维衬纱、线圈的三维仿真模型;以Visual C++ 为开发工具,并且结合OpenGL（Open Graphics Library）图形库,最终在WKCAD4.0系统中实现了轴向经编针织物的CAD设计与仿真功能。     

基于TexGen的经编针织物的三维仿真

针对经编针织物复杂的三维仿真问题,采用TexGen软件对经编针织物进行三维仿真。基于TexGen的建模原理,先确定最小重复单元线圈上的数个节点,通过样条插值的方法获得纱线长度方向的三维中心线,然后通过扫掠二维的横截面,再经过重复最小单元的方法获得经编针织物中纱线的三维几何模型。结果表明,由TexGen对经编针织物进行三维模拟的方法简单可行,模拟得到的效果图中线圈过渡平滑,线圈间的连接较平滑,可达到比较理想的仿真效果。     

成圈型贾卡经编针织物的建模与仿真

从贾卡基本提花原理着手,探讨两针技术的线圈结构;找到各针偏移关系的规律,建立了两针、三针、四针技术相互关联的数学模型,并以VC++6.0为平台进行程序编辑。结果表明,在VC++的基础上,该模型能准确高效地表达各选针技术模型,且模型曲线平滑,显现了线圈真实客观形态。该模型成功应用于鞋面设计的仿真中,取得较好的效果,为经编的生产设计及进一步仿真提供参考。     

经编设备和工艺

一、概说经编是针织方法的一种。在形成经编针织物时,一般采用一组平行排列的纱线,在经编机的所有工作针上同时进行成圈。图1(a)表示了钩针经编机成圈时的情况。成圈时,针升起到退圈位置,使旧线圈退到针杆上,以后后方的眼子针绕针运动,将纱线垫到针钩上,以后再由针的上升、下降运动和压板、沉降片的配合运动在针下降至最下位置时形成线圈。因而经编针织物中,一个横列中的线圈是由许多根纱线同时形成的。为了使经编针织物具有一定的结构和物理机械性能,达到一定的花色效应,往往采用二组或更多组的纱线,形成复杂的组织结构。     

经编针织物三维仿真技术的研究现状与发展趋势

经编针织物三维仿真技术是CAD技术在经编领域的推广应用。三维仿真相对于二维仿真具有更直观、更逼真的效果,但三维模型的建立较为困难,仿真速度较低。经过国内外学者多年的研究,三维仿真技术在经编领域已取得了初步成果。本文从纱线、线圈和织物结构3个层次阐述了经编针织物三维仿真技术的研究历程,分析总结了已有研究成果的优势与不足;并就该技术在未来的发展趋势做了分析,认为三维仿真技术在仿真方法、适用织物品种和应用范围3个方面将有良好的发展前景。通过以上分析,希望为相关研究提供一定的依据。     

基于视觉测量技术构建针织线圈三维结构

采用视觉测量技术中的三角测量原理对针织物线圈进行直接取点测量,并根据光学几何理论提取出纬平针织物线圈上所选取特征点的三维几何坐标值,依据这些点的坐标使用相关数学软件构建出针织物线圈的三维几何模型。这种研究方法是对针织物线圈三维几何结构特性的直接反映,避免了使用传统的几何假设方法进行理论推导时对线圈的过于理想化的假设,能够比较真实地反映出纱线在线圈中的空间形态以及针织物线圈之间的串套效果。在获取线圈几何结构的基础上,通过实验进行验证,证明了其准确性。     

Three-Dimensional simulation of metallic two-bar warp-knitted mesh based on loop structure geometry

In order to predict the appearance and porosity of the metallic two-bar warp-knitted mesh, a three-dimensional (3-D) loop model was developed by some key points on loop, and then based on the model meso structure of mesh was simulated. Firstly, a two-dimensional (2-D) loop geometry in metallic warp-knitted mesh was established. The loop geometry was described on the basis of the yarn property effect to loop sharp. And the underlap geometry was taken as an arc. To describe the 2-D loop geometry, coordinates of key points called databases were established. Then databases in 2-D loop geometry were relocated through the loop offset by stress distribution. Secondly, the 3-D loop geometry was ensured according to the yarn diameter, the angle between loop plane and fabric plane as well as the type of loops (front bar loop or back bar loop), etc. Finally, the coordinates of databases were imported to TexGen software to simulate the 3-D meso structures of the metallic mesh. By comparing simulation images with actual fabrics, the 3-D loop geometry model was fitted well for metallic two-bar warp-knitted mesh. And the simulation results demonstrated that the predicted porosity of mesh was in good agreement with experimental values.     

Parametric modeling of three-dimensional geometry of warp-knitted loop based on variation of process parameters

The purpose of this study is to develop a parametric 3-D loop model for warp-knitted structures which can predict loop geometry with variation of process parameters. Firstly, a process matrix of warp-knitted structure and a matrix including 3-D coordinates of date points were, respectively, developed. Then, based on internal stress analysis, an algorithm were suggested which can calculate the process parameter into 3-D coordinates of date points in geometric model of warp-knitted loop. Moreover, loop model were improved by space curve fitting based on piecewise cubic Hermite interpolating polynomial (CHIP). Furthermore, the developed parametric loop model was programmed with software of Matlab2014, and four test samples with different process parameters were simulated. The accuracy of the proposed model was verified by between simulations and micrographs, as well as agreement between predicted run-in values and the measured ones. It is confirmed that 3-D geometry of warp-knitted loop can be well predicted by the proposed parametric loop model.     

经编朦胧印花生产实践

以涤纶纤维为纱，棉纤维为毛圈纱，采用先印花后拉毛圈的方法，实现了较为明显的朦胧印花效果。对朦胧印花前处理、印花、毛圈梳理等工艺及主要工序要点进行了讨论。     

用作汽车座垫的两种经编间隔织物性能比较

介绍了间隔织物的结构、试验所用原料及复合工艺，比较了海绵座垫与间隔织物座垫的压缩性曲线，说明间隔织物不仅环保而且在压缩性上优于海绵，更适合做汽车座垫。     

经编贾卡提花间隔织物编织工艺探讨

在对专业生产经编提花间隔织物的RDPJ系列双针床拉舍尔经编机结构特征、编织原理、提花原理、设计与仿真原理进行分析的基础上,对经编贾卡提花间隔织物的原料、组织结构等编织工艺进行探讨,并列举了一款该类织物用作功能性鞋子面料的编织工艺,最后结合经编贾卡提花间隔织物的优异性能,指出其在功能性鞋子面料及文胸罩杯等高性能服装面料领域的广阔应用前景。     

An analysis of the bending rigidity of warp-knitted fabrics: a comparison of experimental results to a mechanical model

This study focuses on the bending rigidity of warp-knitted fabrics as a function of knit structure (underlaps length), density (wale and course spacing) and yarn bending properties. Seven standard warp-knitted fabrics are produced with three different densities (Tricot, Locknit, three and four needles Satin, Reveres Locknit, three and four needles Sharkskin). The bending rigidity of the fabrics is measured using a Kawabata evaluation system and an automatic cyclic bending tester. Results show that the bending rigidity increases for the fabrics with a higher density and underlaps length of the front and back guide bars. In addition, a new mechanical model for the bending behaviour of warp-knitted fabrics using an energy method is presented. In this model, the knitted loop structure is assumed to consist of a series of straight and skew yarns simulating legs and underlaps while considering a rigid region lying in the direction of bending. Experimental results show that there is a reasonable agreement between the calculated and measured values for both wale and course directions.     

Analysis of warp-knitted fabric structure. Part II: theoretical study on initial modulus of warp-knitted fabrics (tricot,locknit, and satin)

In the first part of this series, a 3D straight line model was presented for the geometry of two-guide-bar warp-knitted fabrics. In this part, first, the variation of unit cell geometry under uniaxial tension in the range of elastic deformation is investigated. In the present study, the energy method and Castiglianos's theorem were used to derive the fabric's initial modulus. Energy terms which are considered in this study are extension, bending, and compression energies. Also, the friction phenomenon is taken into account by using frictional energy term. For this purpose, the loop of each bar is divided into eight elements. Free-body diagrams of elements are drawn to show the relative magnitude and direction of all forces acting upon an object in a given situation. After obtaining the force details, strain energy of each element is calculated. Finally, the initial modulus of warp-knitted fabrics is obtained. To verify the model, samples of tricot fabrics were produced and tested. Results showed that the generated model can predict precisely the initial modulus of aforementioned warp-knitted structures.     

贾卡经编织物多纹理区域分割技术

为快速准确地得到贾卡经编织物花型图案,提出一种基于小波多尺度分层、马尔科夫随机场建模和贝叶斯最优准则分割理论的贾卡经编织物图像多纹理区域分割技术.首先通过小波变换将贾卡织物图像作多尺度分解等预处理,其次结合马尔科夫随机场理论,运用有限高斯混合算法构建图像灰度场分布模型,采用尺度逻辑算法构建标号场先验模型,最后在贝叶斯理...