织物模拟CAD系统的开发与实现

针对国内纺织CAD软件模拟功能相对较弱的现状，旨在提出一套织物模拟CAD系统的开发与实现方法。首先充分考虑纱线的三维特性并结合计算机图形学技术建立其表面光照模型，然后结合各模拟参数分析、判断，提取出织物表层信息，最后考虑浮长线对织物外观的影响，实现了对织物外观的模拟，模拟效果具有较强的真实感。另外，系统各模块都保持了较高的独立性，模块间的耦合关系也较为松散，以利于系统后期的维护和升级。     

花型织物底纹效果模拟

讨论了在花型织物上模拟纱线交织底纹效果的方法，即通过对织物基础组织矩阵和体现纱线粗细、密度的矩阵闻进行Kronecher叉积运算获得织物底纹效果抖动矩阵，按此矩阵变换花型织物图像的颜色或亮度，实现对花型织物底纹效果的模拟。     

经编贾卡织物的一种仿真方法

通过对经编贾卡织物的组织分析，构造了纱线受力与组织关联的数学模型，并且通过模块映射的方法实现了真实感仿真，较好地模拟了经编贾卡织物的外观。     

一种新的小提花织物计算机模拟方法

通过对影响织物外观效果的纱线真实感的绘制以及对织物浮长效应的处理。得到了较好的织物计算机模拟效果，利用活动模板库技术有效地减少了算法的运行时间。     

基于贝塞尔曲线及柏林噪声模型的纱线外观仿真

对纱线进行的计算机建模及仿真是织物仿真技术的基础.为了提高纱线外观的仿真模拟效果,提出了一种基于贝塞尔曲线及柏林噪声模型的纱线外观仿真方法,即利用随机产生的控制点构造贝塞尔曲线模拟纱线轮廓,利用柏林噪声对纱线毛羽进行模拟.实验证明该方法具有较好的仿真效果.     

起毛织物的CAD技术

毛织物起毛整理后外观会有很大变化，因此，用于毛织物设计的ＣＡＤ系统必需具有模拟起毛织物表面状态的功能。本文阐述起毛织物ＣＡＤ系统模拟起毛的原理和方法，分析了决定织物表面起毛状态的几个因素，提出了独特的模拟方法。介绍了织物起毛状态模拟中起毛．点位置决定、起毛纤维的颜色决定、起毛纤维的形状和长度决定、起毛纤维的方向控制、毛绒密度控制等关键问题的解决办法。用计算机图像模拟方法模拟了生产过程中起毛后整理对毛织物外观产生作用的全过程。     

基于Matlab的不同材质三维纱线模拟技术

为了模拟真实感较强的三维纱线,从纱线的本质分析入手,探讨柔性纱线模拟过程存在的主要问题,确定影响纱线外观模拟的主要因素有纤维的长度和细度、纱线的细度、捻度和蓬松度等.选用Matlab模拟工具和纤维级模拟方法实现不同长度和细度纤维构成纱线的三维外观模拟,为不同材质三维纱线模拟探索一种方法.论述了基于Matlab的三维纱线模型的建立方法,并通过不同细度纤维构成纱线对比效果图和三维映射后三维纱的模拟图,验证了该法可以模拟出真实感较强的三维纱线,指出线性模拟和三维映射2种方法的主要用途和发展方向.     

织物的膜理论

为了对织物膜结构和服装进行虚拟模拟，例如膜结构的张紧和褶皱以及服装的悬垂和屈曲，建立了编织物的膜理论．编织物的细观编织结构被引入了膜理论，织物的经线和纬线被选为曲线坐标轴，未变形的纱线作为Lagrangian坐标轴，变了形的纱线作为Eulerian坐标轴．在变形中考虑经线和纱线之间夹角．该理论被用于织物膜的张紧分析．数值结果表明，当应变e12达0．06时，由于纱线夹角的改变导致的应力增加占总应力的25％左右．     

基于BRDF算法的机织物表面外观模拟

为了增强织物表面纹理的真实感效果,在原来简单的纱线模型基础上再考虑光照模型因子,由纱线的双向反射分布函数绘制出织物的细微结构.提出了织物交织的光照效果生成算法及其在机织物模拟中的应用,经过BRDF算法改良的织物模拟系统,能够模拟出织物表面的细致纹理,对于质地粗糙、复杂纹版组织的大型提花织物等模拟效果更佳.     

股线的数学模型和外观模拟

通过对股线外观统计特性的分析，建立了股线捻回的随机矩阵模型，并给出了生成随机矩阵的方法。该方法可以模拟单色股线和多色股线，效果比较逼真，并为模拟具有真实质感的织物外观奠定了基础。     

单面羊毛衫添纱织物编织的研究

分析了垫纱横角和垫纱纵角对羊毛针织绒线在织物中显现情况的影响规律，推导出了横机纱线断面轨迹方程，通过上机确定了编织毛盖棉织物时较理想的垫纱角度．     

Web-Based Interactive Simulation of Weft Knitted Fabric

In order to realize parametric simulation of three- dimensional (3D) fabric structure based on web,a 3D model describing a plain knitted fabric,in which the cross- section of the yarn is circular shape and the path of the yarn is cubic B-spline curve,is proposed in this paper. With this model,the 3D simulation of the loop and of the basic structures of the knitted fabrc is realized by using Virtual Reality Modeling Language (VRML). The virtual simulation scene is suitable for network transmission with freely available VRML browsers and can be translated,scaled and rotated quite arbitrarily. By using Java and External Authoring Interface (EAI) technology,the web- based interactive simulation platform of weft knitted fabric is established. The user can input type of structures,basic fabric parameters,and yarn colors interactively to obtain a more realistic simulation result in real-time. A new approach is provided to imitate the knitted fabric 3D appearance on network.     

线圈残余曲率与织物外观形态关系的研究

分析了织物中线圈的形态 ,推导出了线圈残余曲率与纱线细度、纱线机械性能及成圈机件尺寸之间的关系式 .在理论分析和实践的基础上讨论了线圈的残余曲率与织物外观形态和尺寸间的关系     

Analysis of the Appearance Diameter of Yarns in Worsted Fabrics

Three-dimensional Rotational Microscopy was used to take the photos of the fabrics. Three categories of yarn appearance diameters in the worsted fabrics were discussed. The fabrics were grouped into two to explore the relationships between yam appearance diameters at the interlacing points, opening points, and the calculated yam diameters. The correlations between the appearance diameters and fabric parameters were given, and the results showed that the calculated yam diameter and warp cover factor had a very big influence on yam appearance diameter. The equations expressing the relationship between yam appearance diameters and fabric parameters are established using step-regression method. The validation of the equations for one type of fabrics shows a good accuracy with the average error below 9% except the weft fdaments exceeding 22%.     

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.     

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。     

VARIATION OF WOVEN FABRIC GEOMETRY——Non-uniform Flattening of Yarns

In previous research much effort has been devoted to the geometry of woven fabrics and relat-ed problems under the assumption of constant yarn configuration in fabric.This paper will first re-port that image crimp (yarn crimp measured by an image analysis method) seems larger than actualvalue.From the explanation of this result,the variation of yarn configuration in woven fabric dueto the non-uniform flattening is revealed.The significance of this actual structure of woven fabricsis discussed.It is believed that the variation of yarn configuration is very important for fabric per-formance,and may be an advantage for fabric quality.     

计算机测配色技术在纺织品图案设计中的应用研究

在分析纺织品图案与色彩构成的基础上,通过研究色彩的空间混合原理,提出了利用计算机编程技术处理纺织品图案设计中织物经纬纱线的配色问题.利用计算机测色技术建立纱线颜色库,再利用配色程序计算出经纬色纱交织后所形成的织物色彩,从而模拟纱线混色后织物的效果,达到快速配色的目的,这样就极大地简化了色织物中经纬纱线的配色问题,提高了纺织产品开发的效率和劳动生产率,能更好更快地满足客户和市场需要.