Virtual Garment Sewing

Introduction3D garment CAD tools are increasingly required byclothing industries to assist the cloth design andmanufacturing process for quick response when faced withrapidly changing in style and fabrics with variable materialproperties. In the context of virtual prototyping, modelingand simulation of garment fitting to mannequin areattracting more and more people from both research andindustrial communities.Different approaches and techniques can be used…     

虚拟环境中三维贴体衣片的设计

介绍了在虚拟环境中利用鼠标和三维空间交互球选取并控制人体模型上的点，将之作为三维衣片边界上的点，结合相应的数据结构，得到三维衣片轮廓线的点、边、衣片结构，接着利用插值的方法生成边界内的点，然后Delaunay三角化，生成衣片的三角面片，并将之演示出来。本文的创新点主要有以下几方面：开发了一个三维衣片设计系统，该系统集成了一套小型虚拟现实系统(小型立体显示观察系统和三维空间交互球)，在该系统生成的三维虚拟环境中，设计者可以引入由美国(10)公司三维人体测量系统生成的真实人体模型，在此基础上自由设计三维衣片，该系统提供了一些交互手段，使设计者可以像在真实三维环境中设计衣片一样，提供了直观的设计效果，该系统是用VC 6．0和opengl开发的；介绍了一种新的插值方法，利用这种特定的方法，可以得到符合人体且具有一定空隙量的贴体三维衣片；对Delaunay三角化生成的三角衣片，进行了改进，去掉了位于三维衣片凹边外的部分，从而得到了完全符合衣片设计轮廓的三维衣片。     

FINITE ELEMENT SIMULATION OF FABRIC CANTILEVER TEST

The present paper describes the application of the finite element technique to simulate large fabric deformations in the case of a rectangular cantilever. The fabric is simulated using a degenerated isoparametric curved shell element with 8 nodes. The cantilever is considered as a special case of a three dimensional shell structure. The finite element formulation takes into account nonlinear material properties of fabrics. Simulation of woven fabric cantilevers is made and the results are compared with the test results to examine the effectiveness of the finite element approach.     

用牛顿-条件预优共轭梯度法求解光滑支持向量机的可能性研究

光滑支持向量机是目前的一个研究热点.牛顿-条件预优共轭梯度法Newton-PCG(Newtonpreconditioncd congugate gradient)是一种求解优化问题的更有效算法.列出了该算法用于求解光滑支持向量机的基本思想和基本步骤,还比较了原始牛顿法和牛顿-条件预优共轭梯度法的计算效率.结果表明,牛顿-条件预优共轭梯度法的计算效率明显高于原始牛顿法.     

Bending Hysteresis of Twill Woven Fabrics in Various Directions

This paper investigates the bending hysteresis of twill woven fabrics in various directions. In this research, existing models for the prediction of bending rigidity of woven fabrics are applied to bending hysteresis. Wide range of cotton twill woven fabrics is examined by comparing the theoretical data and experimental results. The results of this paper indicated that Peirce's, Shinohara et al's and Cooper's models can be applied to the prediction of bending hysteresis of twill woven fabrics. Besides, the results also show that ratio V, introduced by Cooper, of a cotton twill fabric is found to have the range between 0.8 and 1.4. The general shape of the polar diagram of bending hysteresis along the weft direction is spreading outwards with the increase in ratio V from the range 0.8 to 1. However, the general shape of bending hysteresis will collapse around the weft direction when ratio V is increased from 1 and 1.4.     

Study on Bending of Woven Fabrics Using Linear Viscoelasticity Theory

The bending behavior of woven fabrics under low curva-ture conditions has been analyzed by linear viscoelastictheory.The fabric is assumed to behave viscoelasticallyand to be subjected to frictional restraints in bending de-formation.The frictional restraint is considered to beproportional to the curvature and can be described by africtional moment.A model has been constructed by astandard three-element solid model and a paralleledfrictional sliding element.The equations of the model fora cyclic curvature variation are derived.A set of param-eters of the equations for each fabric has been obtainedexperimentally.Predictions of the bending rigidity andhysteresis for wool,cashmere,wool/polyester blended,polyester and cotton fabrics are made,displaying verygood agreement with the experimental observations.     

支持向量机的光滑与逼近关系研究

支持向量机是近年来数据挖掘领域发展起来的一个新方法.对现有的四个光滑支持向量机进行了分析,研究了支持向量机的光滑与逼近的关系.数值实验结果表明,支持向量机在具有二阶光滑的条件下,分类效果随逼近精度的提高而改善.     

用光滑的支持向量机解回归问题

解回归问题通常采用平方损失函数,传统方法在函数类的选择上是一个难点。采用ε-不敏感损失函数,用光滑的支持向量机解回归问题。数值实验表明,只需选一个核函数就可较好地解决这个难点,使支持向量的个数明显少于样本点的个数,简化了回归函数的表达式,回避了传统回归方法选择函数类的困难。所以,光滑支持向量回归机是解决回归问题的一个有效方法。     

MODELLING OF TENSILE STRESS-STRAIN CURVE OF WOVEN FABRICS

A general shape of tensile stress-strain curves of woven fabrics is first recognised by puttingtested and predicted results together.An exponential function with two parameters is then selectedfor the prediction of tensile stress-strain relationship.The predicted results by using the proposedfunction show excellent agreement with experimental data.