纱线的计算机模拟

提出了用擦去四个角的平行四边形来模拟单纱和股纱的方法。根据组成纱线纤维材料的不同，制作不同的纱线模板，按照用户输入的参数生成不同的纱线毛羽，得到了良好的模拟效果。     

气动折入边装置中纱线初始位置对折边效果的影响

为改进气动折入边装置的结构设计,提高纱线的折入效率和稳定性,采用数值模拟和实验相结合的方法,探究纱线初始位置对纱线折入的影响机制。基于单向流固弱耦合算法提出了适用于模拟纱线从斜吹到折入行为的数值模型,探究一端固定另一端自由的单根纱线在不同初始位置先后受斜吹和折入气流作用的运动规律。搭建可视化实验平台,通过高速摄像机记录纱线的运动行为。通过数值模拟结果和实验数据进行比较,验证了单向流固弱耦合算法的准确性。结果表明:纱线折入所需的时间和伸长量与其初始位置有关,折入效果与其初始纵坐标有关;不同初始位置的纱线均能在7.425 ms内完成折入。     

用B样条曲面构建纱线三维模型的研究(Ⅱ):纱线捻度的三维模拟

在用B样条曲面构造具有不同截面的纱线三维模型基础上,对截面随机加上凹凸扰动,并沿着纱线的径向对各个截面进行旋转,使得纱线表面产生波浪状的捻度效应,相当于在纱线表面添加了三维凸包纹理,提高了模拟纱线的逼真程度,对于圆形截面纱线的效果特别显著。     

织物仿真CAD在纱线模拟技术方面的新进展

纱线设计是织物仿真CAD中一个重要的模块,纱线模拟的好坏直接影响到织物模拟效果。本文从纱线细度、纱线捻度、纱线毛羽、纱线类型、纱线颜色、纱线模拟光照模型、纱线模拟效果等方面对纱线设计模块进行了详细阐述。此系统的实现为下一步的织物仿真模拟打下了坚实的基础。     

采用色纺纱图像的真实感色织物模拟

为解决色织物产品设计周期长,试织打样耗时费力的问题,提出一种采用色纺纱图像的真实感色织物的模拟方法。首先采集彩色纱线图像,运用阈值分割、形态学处理得到纱线主体,获取纱线主体的上、下边界和中心线,进而得到原始纱线图像的主体部分;接着根据椭圆模型和正弦曲线模型对纱线主体图像进行处理,得到纱线在二维织物表面中的形态;最后根据色纱循环和织物组织变换模型来改变经纬纱的覆盖关系,实现了真实感条纹型和格子型色织物的模拟。模拟结果表明：本文算法能够模拟不同种类色织物的织造过程,真实地反映织物的外观效果,且能够调整织物组织和色纱循环参数,提高了现有模拟算法的真实性和适应性。     

旋流喷嘴对不同线密度纱线的作用机制

为研究旋流喷嘴纺纱方法对不同线密度纱线的减羽效果,借助计算流体软件模拟旋流喷嘴内部气流特性及不同线密度纱线在气流作用下的压强与速度分布,并用纺纱试验进行验证。模拟结果表明,进入纱道后的气流沿顺时针方向分别朝纱道入口及出口方向运动,纱线表面毛羽主要受到气流的包裹力和由于纱线自转而产生的相对包裹力作用。气流的旋转特性使得纱道管壁附近的压强高于轴线附近,因此不同线密度纱线的表面所处涡流的位置不同,受到的气流包裹力也不同。纱线线密度较小,表面受到的压强分布密集,x、y、z 向速度波动较大,其中20 tex 纱线表面的压强和速度分布情况优于10、30、40 tex 的。研究结果表明,旋流喷嘴压强在0.2 MPa 下,对20 tex 大麻/ 棉（40/60）的减羽效果最优,达到了87.6%,与数值模拟结果一致。     

平纹机织物空间参数化模型及仿真

在Peirce模型的基础上,采用圆弧和切直线描述纱线的屈曲形态,采用圆形描述纱线截面形状,基于坐标变换原理,建立了平纹机织物空间三维形态的数学模型。在此基础上,采用MATLAB语言编程,对平纹机织物进行参数化建模,实现平纹机织物在不同经纬纱线直径、不同经纬纱线密度、不同结构相下的三维仿真,并通过颜色插值、添加光源等改进模拟效果。     

基于Matlab的机织物结构相三维仿真

为真实、快速、形象地显示织物,基于Peirce及其衍生模型采用正余弦函数模拟了纱线屈曲状态;利用圆形和椭圆形分别描述纱线截面形态,避免了纱线弯曲处出现尖角或交叉;加入织物多类控制参数,实现了不同纱线直径、经纬密、结构相、纱线线密度的快速变换控制。基于坐标变换原理,建立了以空间曲面描述织物三维形态的模型;采用Matlab语言进行编程,基于所建数学模型进行三维结构形态模拟;加入颜色插值、添加光源等,更好地进行了仿真效果呈现。     

纱线的外观模拟及系统实现

通过对纱线外观统计特性的分析,建立未加捻单纱和加捻股纱不同的光学模型,使用HLS颜色空间得出其不同的亮度矩阵,结合输入的纱线参数来模拟单色股线和多色股线,绘制简单、快速,效果比较逼真,并用VC 编程语言来实现,为模拟具有真实质感的织物外观奠定了基础.     

纱线动态与静态断裂强力的比较分析

对纱线动态和静态断裂强力的测试原理进行比较,并通过数学分析方法对测试结果进行定量分析,指出纱线动态断裂强力比静态断裂强力大约降低了20%~30%,说明将动态断裂强力作为衡量纱线品质指标具有实际指导意义。同时提出采用CTT纱线传导系统测试纱线动态断裂强力不仅可用不同的测试速度模拟纱线的使用情况,而且能够更好地显示纱线弱节的强力性质,更能反映纱线在生产中的强力品质。     

PTT/毛混纺纱性能测试与评价

对规格相同的PTT/毛和PET/毛混纺纱进行测试,对比分析PTT/毛混纺纱线的毛羽、拉伸性能、回弹性能及沸水收缩率。实验结果表明,PTT/毛混纺纱线毛羽较少,纱线拉伸模量低于PET/毛混纺纱,纱线拉伸断裂伸长率较高;PTT/毛混纺纱在定伸长5%条件下,弹性回复率达到96%,在定伸长15%的条件下弹性回复率达到87%,且急弹性回复率大于PET/毛混纺纱;PTT/毛混纺纱的沸水收缩率与PET/毛混纺纱的沸水收缩率相比差异不大,都具有良好的沸水稳定性。     

基于BP网络的成纱质量预测的数据挖掘

通过对原棉性能及成纱质量历史数据的分析，建立了用于数据挖掘的样本库。在此基础上设计了成纱质量预测的BP神经网络模型，并对成纱的强力、条干CV值和毛羽等质量指标进行了预测分析，仿真结果表明该方法具有很好的预测效果。     

浅析毛羽的成因及预防措施

织物上过多的毛羽会严重地影响织物风格,是制约产品档次的一项重要因素.在对纺纱过程中产生毛羽的原因进行了全面的分析后,通过在配棉、粗纱、细纱、络筒等工序采取有效的措施,以及合理控制各工序的温湿度,达到了减少毛羽产生的目的,为降低毛羽率提供了可参考的价值.     

高支全毛单经单纬产品的开发

探讨了利用水溶性聚乙稀醇 (PVA)纤维所纺单纱与全毛单纱并合加捻成股纱形式进行织造 ,再通过后整理将PVA单纱溶掉 ,得到符合要求的全毛高支轻薄型单经单纬产品的工艺方法     

Characterizing the thickness variations in ring spun yarns

Abstract

The quality of textile products is an important criterion for customers in determining whether to purchase a textile product or not. When a textile product reaches the level of mechanical and physicochemical properties needed as a quality product, its final criterion for marketability is made by its apparent quality. The visual quality of textile products is closely related to the irregularity of the constituent yarn thickness. This paper reports the results of a study on the thickness variation characteristics for various yarn types, that is, single staple yarn, two-plied yarn, and three-plied yarn, which look different when seen visually. For measuring yarn thickness variations we adopt the optoelectronic method based on a laser slit beam, which is among the several methods used for measuring yarn thickness, since the diameter of yarn cross-section provides new information on the thickness attributes that can influence the apparent quality of yarn and fabrics. For the purpose of characterizing the yarn thickness variations, we apply correlograms and variance—length curves. We can confirm that different types of yarns have their own unique thickness variation characteristics. Furthermore, it is identified that not only the thickness variance between the specimen lengths, but the total variance itself also changes according to the specimen length, that is, the sensor head size. We can estimate the ultimate thickness variance by using a curve-fitting method.     

基于环锭细纱机的彩色纺纱及其产品创新

纵观每年举办的国际流行纱线展,创新的针织面料有很大一部分是基于纱线色彩的多样拼接和搭配,以此呈现出不同风格及效果。因此,愈加多元丰富的面料对纱线提出了新的要求,需要以纱线为基础载体呈现多样的颜色风格及效果。目前,有色彩效果的纱线开发和研究主要聚焦在3个方面:一是基于环锭细纱机生产的段彩纱、云纹纱、麻灰纱等;二是基于四色针梳机开发的渐变色彩纱;三是基于其他新型纺纱方法,如摩擦纺、转杯纺等纺纱方法开发的纱线。文章基于前期分别在四色针梳机和摩擦纺纱机上开发不同风格彩色纱线的工作,主要介绍近期新研发的彩色纱线,分析用环锭细纱机研发彩色纱线的创新方向。     

An extended virtual location method for yarn cross-section construction

The first step in the evaluation of physical phenomena in yarns consists of creating a suitable representation of the yarn. Here, we focus on the creation of a realistic grid for the yarn cross-section, which is suitable for mass and heat transfer models. We extend and adapt the virtual location method (VLM) which allows the quick creation of a range of 2D yarn–fiber layouts. We overcome two of its main disadvantages: the presence of too much regularity, and the inability to produce yarn–fiber layouts when blends of fibers with different sizes are present. Our method is based on the standard ring configuration VLM, creating two sets of virtual locations per fiber type, which causes some overlap of the fibers. The overlap is removed with an iteration scheme based on induced movement. The final result is a realistic 2D cross-section of a yarn. A reference implementation is available, and it is shown how the layout can be used to create a grid.     

Investigation of effect of fibres modulus on pilling of acrylic fabrics

Pills are formed by entangling fibres into discrete balls on the surface of fabrics which are usually the result of wear, abrasion, washing or a combination of all three. In the present study, the effect of initial modulus of fibres on the pilling of woven fabrics was investigated. For this purpose, non-shrinkable (regular) and shrinkable (high bulk) acrylic fibres which have different initial modulus, were used. By using different percentages of them, five kinds of yarn were produced. Twill woven fabrics (T 1/2 z¹) produced from these yarn were tested on ICI pilling box tester.

Results of pilling test performed on the sample showed that by increasing the percentage of non-shrinkable (regular) fibres with high initial modulus, the tendency of fibres to leave the structure of yarn increases and they will present on the surface of fabrics as pills.     

Ring frame process parameters and fabric comfort. Part I – low-stress mechanical properties of fabrics

Influence of ring frame process parameters, namely twist multiplier of yarn, spindle speed and ring frame draft, on some of the yarn characteristics has been studied. The low-stress mechanical characteristics of woven and knitted fabrics made out of these yarns have also been reported in the present paper. Yarn packing factor, which is directly related with the yarn diameter, has direct impact on fabric comfort related characteristics. All the studied ring frame process parameters, i.e. yarn twist, ring frame draft and spindle speed, have inverse effect on the yarn diameter, which means the yarn diameter reduces with the increase in one of the process parameters by keeping the other two parameters constant. The impact of draft on reduction in yarn diameter is found to be higher as compare to other two parameters. All these ring frame process parameters have significant impact on other yarn parameters also. The increase in yarn twist, spindle speed and draft result in increase in flexural rigidity, unevenness and imperfections of yarn and decrease in yarn hairiness. All the low-stress mechanical properties, i.e. tensile, shear, bending, compression and surface, of both woven and knitted are affected by the above ring frame parameters. The thickness of fabrics changes with the yarn compactness, i.e. with the reduction in yarn diameter. The study revealed that by changing the above ring frame process parameters, it is possible to manipulate the fabric handle characteristics without changing the fabric constructional parameters.     

网格圈目数与纱线综合性能关系的研究

网格圈是紧密纺纱技术的关键部件，其空隙的大小及织造密度的高低都对纱线的性能有影响。文章分析了不同目数的网格圈对不同线密度纱线性能的影响，同时讨论了纺制不同线密度纱线对网格圈的选择。