芳纶平纹织物单纱抽拔力学性能分析

为探究芳纶平纹织物抽拔力峰值和横向预张力受各因素影响机制和变化规律,通过在电子万能试验机上加装自主设计的快速对中夹具和力传感器,进行了以横向预张力、抽拔速度、试样规格和纱线类型为变量的单纱抽拔实验。结果表明：抽拔力和横向预张力在抽拔过程中发生同频率零相位差的震荡下降,抽拔力峰值与抽拔纱线的交织点数量、交织点处的张力和变形程度呈正比关系;当初始横向预张力从100 N增加至400 N时,抽拔力峰值从5.63 N增加至10.58 N,横向预张力的上升值降低,下降值增加;当织物纵向长度从30 mm递增至110 mm时,抽拔力峰值增加,峰值增幅降低;抽拔过程中,横向预张力的上升值和下降值都随着织物纵向长度的增加而增加;纱线织造密度越小,预紧后的卷曲程度越高,抽拔力峰值越大。     

基于数字单元法的三维正交织物微观几何结构建模

为了反映织物内部纱线的空间构型和微观几何结构,针对在织物建模过程中,因忽略纤维间的相互作用而引起的纱线截面形状变化的问题,基于数字单元法理论,提出了一种计算纤维间摩擦力的方法。通过纱线纤维化离散,用数值模拟和仿真方法模拟三维正交织物成型过程,建立了5种精度递进的微观几何结构数值模型。5种模型中的每根纱线分别由4、7、12、19和37根数字纤维表征。研究结果表明:随着纱线纤维化离散程度的提高,仿真时间延长,织物厚度减小,纤维体积分数增大,节点平均作用力下降速度变缓,势能变小;当每根纱线由19根数字纤维组成时,所建织物的微观几何结构数值模型与真实织物样本在显微镜下的内部切片图像较为吻合。     

中低密度机织平纹织物中纱线压扁变化规律

摘 要 为了探讨真实描述平纹织物结构中纱线截面的几何形状,需要测量沿纱线中心线方向的压扁程度。设计并织造了经向紧度和纬向紧度分别为34.72%、43.4%、52.08%的9块中低紧度布样,用Keyence数码显微镜获得布样上经或纬组织点图片,非破坏性地实际测量组织点不同位置处纱线直径。利用Excel和Origin软件对测量数据的输入与处理、绘制测量位置与压扁系数的点线图,分析沿纱线中心线方向纱线截面的变化规律和不同紧度的织物中经纱或纬纱的压扁程度。发现纱线截面的压扁系数与组织点的中心位置距离呈现高度线性相关,距离越近,压扁程度越大;中低织物紧度条件下,紧度对纱线压扁系数影响不明显。     

用变截面纱线模型模拟平纹织物的研究

为了逼真模拟平纹织物,采用变化尺寸大小的锯齿形椭圆截面的纱线模型,结合B样条曲面造型技术,利用Peirce机织物模型构造平纹织物的几何立体结构.根据VC程序运行结果来看,该纱线模型结合捻度结构用于模拟平纹织物的效果逼真.     

三维正交织物织造过程模拟及其微观几何结构预测

为获得更为精确的织物模型,以满足织物及其纺织复合材料力学性能和破坏机制分析的需要,针对多尺度材料几何结构建模中存在宏观和介观尺度理想化假设,从而导致织物微结构特征缺失的问题,基于数字单元法理论,在纤维尺度提出一种织物织造过程动态仿真方法。该方法建立了织机关键部件的几何模型,由织造矩阵控制开口运动,通过计算纤维间的相互作用力,模拟织机五大运动,得到4个处于不同织造时期的单胞组成的三维正交织物数值模型。研究结果表明：织物单胞的微观几何结构受相邻单胞的影响,在织造过程中发生变化;最上层和最下层纬纱的应力高于中间层纬纱;模型较为准确地描述了纱线的卷曲、路径和横截面形状等织物的主要特征。     

线迹缝合对芳纶平纹织物抗侵彻性能的影响

为了增强纱线间约束,提升平纹织物的抗侵彻性能,通过线迹缝合技术对织物内部纱线进行缝合.抽拔试验结果表明:线迹缝合有效增强了经、纬纱之间的摩擦力,织物的最大抽拔力随着缝合线迹数量的增多而增大.此外,线迹缝合增加了平纹织物的硬挺度.侵彻试验结果发现:高速侵彻降低了织物的能量吸收能力;试样的能量吸收能力随着相邻2根缝合线迹间距的减小而增大,其中每根纱线缝合试样的能量吸收能力最大;试样的贯穿比能量吸收能力随着相邻2根缝合线迹间距的减小呈现先增大后减小的趋势,每隔1根纱线缝合试样的贯穿比吸能最大.缝合结构与平纹组织的复合工艺为软体防弹服内胆防护层的优化设计提供了可行性方案.     

基于可调张力装置的芳纶织物交织阻力研究

为更加真实地模拟芳纶织物在受到冲击时产生的交织阻力变化情况,通过构建一个半经验模型来预测对于不同规格、不同预加张力情况下纱线交织阻力的数值,并设计了可调预加张力的纱线抽拔实验用夹具,分别以织物的经向宽度、纬向宽度和预加张力为变量对纱线进行抽拔实验.实验结果表明:对织物施加横向预加张力与纱线抽拔时的交织阻力呈正相关,预加...     

平纹机织物单元结构热湿传递的数值模拟

通过建立平纹机织物单元结构3D热湿传递的数值模型来研究在热湿从人体皮肤通过织物传递的情况下，任意时刻的热流量和湿流量在织物内部的传递规律，并采用MATLAB语言编程对模型数值求解。模拟结果表明：织物内部温度场、湿分浓度场具有明显的时间效应，任一时刻网格单元节点处的温度、相对湿度随时间的变化而变化并逐渐达到平衡状态。这对于深入研究服装动态热湿舒适性具有重要的指导意义。     

外套管状机织物抽拔过程的动态数值模拟

运用有限元分析法对管状机织物外套于管子时的抽拔过程进行了应力应变分布动态模拟和计算。结果表明基于所建立的管状机织物三维模型,在考虑了经纬纱本身结构非线性关系及管子与织物接触的非线性条件下,所得管状机织物的应力、应变分布及其最大值与常理性应力、应变分布基本一致,应力和应变的最大值发生点完全一致。同时管织物的接触长度对最大应力和应变值及其发生位置有明显影响,且接触长度增加会导致自锁。这为管织物抽拔自锁和破坏预估计提供了有效的预报方法。     

采用ABAQUS的粘胶机织物拉伸力学性能仿真

为预测织物拉伸性能,采用有限元方法对织物拉伸力学进行数值模拟分析。在实测织物几何结构参数的基础上,借助纺织建模软件Texgen建立了织物模型;利用有限元软件ABAQUS模拟织物拉伸环境,设置材料属性、相互作用和边界条件,得到织物拉伸变形后应力分布云图以及拉伸时应力—应变曲线图等数值模拟结果;最后通过织物拉伸强力测试实验对数值模拟结果进行了验证。结果显示：模拟所得应力—应变曲线和实验所得拉力—伸长曲线上升趋势大致相同;模拟所得最大拉伸应力与实验所得拉伸应力平均误差为3.03%,证明了采用ABAQUS有限元软件模拟粘胶织物拉伸力学性能的是可行的。     

纱罗组织对芳纶织物交织阻力的影响

为增强芳纶机织物的纬纱交织阻力,将纱罗组织和平纹组织结合,以提升纬纱对横向抽拔作用的抵御能力。通过准静态纱线抽拔试验发现：在交织阻力位移曲线的退屈曲区内,纬纱的最大交织阻力和经纬纱屈曲交换程度密切相关;在黏滑区内,曲线呈现出一种震荡衰减趋势;纱线所受的交织阻力和被抽拔纱线根数几乎呈线性关系;同时抽拔2 根、3 根和4 根纱线的最大交织阻力对比于单纱抽拔的最大交织阻力的增幅分别是160% 、289% 和 389% ;纱罗组织的引入,有效增强了经纱对纬纱的握持性能。单纱抽拔试验结果表明,平纹/纱罗复合结构织物的纬纱所受最大交织阻力比平纹结构增加约20% 。多纱抽拔试验结果表明,交织阻力的最大增量约为65% 。     

Theoretical and experimental analysis of bending rigidity of plain and twill woven fabrics

The study of bending behavior of woven fabrics is an important issue in textile scientific researches and its industrial applications. Different behavior of fabrics such as drape, comfort, and handling can be understood by this study. Bending rigidity of fabric depends on several factors such as weave geometry, bending rigidity of yarn, and yarn density. In this study, estimation of bending rigidity of woven fabric with different twill and plain structures, have been carried out using energy method. Generally, the woven fabric structure is divided into three different section lengths i.e. rigid, semi-rigid, and flexible sections. Thereafter, bi-component and tri-component models for predicting bending behavior of plain and twill woven fabric have been presented. Then, bending properties of fabric based on Shirley apparatus as well as weight per area as a physical property were measured. Good agreement between measured and predicted values, validated our theoretical models for obtaining bending rigidity, except considerable differences observed between experimental and predicted values using bi-component model of plain fabric. Therefore, using assumptions in calculation of the ratio of rigid section length to flexible section length (R₁), the modified model of plain fabric has been proposed.     

The effect of yarn twist direction on the formability of woven fabrics

This experimental work examines the influence of the yarn twist on the formability of a woven fabric. Consideration is given to the phenomenon of bedding between warp and weft yarns, as affected by the local helix angles of bent yarns. A total of 28 plain weave woven fabrics (four groups, each with seven samples) were produced, using Solospun? yarns as warp and weft threads. The fabric bending length and the initial modulus of each sample were measured from which the formability was calculated. Results indicated that the fabrics in which the warp and weft twists are unidirectional (Z &; Z) have higher formability in comparison to those fabrics in which the warp and weft twists are opposite to each other (Z &; S). In addition, among the former fabrics the highest formability belongs to those in which the total helix angle of the warp and weft is close to 90 degree whereas the lowest formability belongs to the latter fabrics with least amount of twist.     

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。     

Study on microclimate conditions for woven fabrics from cotton-acrylic bulked yarn

The present work is concerned with the study of the microclimate conditions with plain woven fabrics produced with cotton-acrylic high-bulk yarns. Cotton-acrylic bulked yarns of various yarn counts, proportion of shrinkable acrylic fibre and twist levels have been prepared as per the three-variable three-level factorial design technique proposed by Box and Behnken to study the interaction effects of the variables on the microclimate conditions. The influence of these three variables on various microclimate conditions i.e. initial increase in microclimate temperature and relative humidity without air flow and drop in microclimate temperature and relative humidity when air flows at 1.12?m/s through the outer surface of fabrics. The response surface equations for all the microclimate parameters have been derived and the contour plots were obtained to analyse the interactive effect of all the variables on microclimate parameters. These bulked fabrics show higher initial increase in microclimate temperature without air flow and lower drop in microclimate temperature with air flow as compared to equivalent 100% cotton fabrics. All the variables were found to have significant effects on microclimate parameters.     

竹节纱机织面料的疵点分析和防范措施

分析了竹节纱在机织面料上形成的疵点类型和特点,并根据设备情况按工序提出了具体的防范措施,认为竹节的粗度及其在布面上的分布规律都会影响竹节纱织物的风格,生产前应要多试纺试织,以免造成浪费。     

Computer simulation of plain woven fabric appearance from yarn photographs

This article proposes a method for simulating plain woven fabric appearance based on photographs taken by still camera of actual yarns along their lengths. The survey mathematically models the transformation of yarns from a straight circular cylinder to a flattened and crimped form in the fabric structure. The simulation is performed by yarn images that are obtained by image processing techniques and resized according to mathematical models developed by means of the software prepared. Transforming circular yarn cross-section to elliptical one for simulating yarn flattening and modelling the crimped shape of yarn by an elastica curve are both convenient and realistic. The simulation of plain woven fabric can be performed by a method based on raster graphics. This article provides a model for yarn shape in fabric structure as well as a method for simulating plain woven fabric appearance. This method may be used in textile industry for design and quality control.     

应用纱线序列图像的电子织物构建

为检测纱线条干均匀性对织物外观的影响,在纱线条干图像测量的基础上,提出了一种基于纱线序列图像的电子织物的构建方法。通过建立织物组织变化模型和光照模型,将纱线直径值与基元组织点外观灰度纹理分布相结合,构建电子织物外观数学模型。实验中通过将采集的纱线序列图像进行图像分割和形态学运算等处理,获取纱线直径数据,代入到构建的织物外观数学模型中,实现基于纱线序列图像的电子织物的模拟并且相关参数可调。通过选择合理的织物结构参数,提出的电子织物模型能够真实的反映纱线条干均匀性对织物外观的影响,准确预测布面效果。     

平纹织物纱线截面形态经典理论探析及其泛化

平纹机织物内部纱线的截面一直被业界视为某种固定的形态,但应用可视化技术发现,基于经典的双凸截面模型存在问题,即使用微积分思路解决问题过程中,发现纱线截面变化的规律.研究结果表明,无论是单层机织物还是多层机织物,其纱线截面均呈现多元性,而非单一形态.特别是对于接结多层纬纱的经纱,其截面沿纱线长度方向按凹凸交变的规律呈周期性变化.这一研究成果对"织物纱线恒定截面论"提出了异议,对研究纱线的真实截面形态及织物外观模拟具有参考价值.