Prediction of Final Velocity of Aramid Fabric-Resin Composite Laminates Subjected to Ballistic Impact

The strain rate effects of aramid fiber material, quasi-static and ballistic impact perforation of composite laminates made of aramid fabric and phenolic resin/PVB are investigated respectively by means of MTS, split Hopkinson tension bars and ballistic impact apparatus. The tensile impact experiments on aramid fiber material are performed in strain rate range from 0.01/s to 1000/s. Experimental results show that the mechanical properties of aramid fiber material are insensitive to strain rate in the range from 0. 01/s to 1 000/s. An energy model to predict final velocity of composite laminates subjected to ballistic impact is proposed on the basis of experimental data of quasi-static perforation through the targets. The predicted final velocities show good agreement with the experimental final velocity.     

羊绒纱线的扭转及扭矩松弛性能

采用带有热箱，可通蒸气的扭转平衡型扭矩测定装置，对比测定，研究了羊绒，羊毛纱线在标准温、湿度及湿热条件下的扭矩－捻回数关系和扭矩松弛性能，并测试分析了预加张力对羊绒纱线扭矩松弛性能的影响。     

Gore-tex防水透湿层压织物的概述

介绍了各类防水透湿织物的种类、性能及研究发展状况,着重叙述了商品名为Gore-tex的PTFE微孔膜层压织物,并提出了存在的问题.     

The Influences of Ultrasonic on Embedding Nano Particles into Porous Fabric Materials

The feasibility of embedding 40 nm ZnO particles into porous textile material by using ultrasonic and its influence factors were studied. Through investigations, it is proved that the higher the concentration of nanoparticle suspension is, the higher the weight of embedding percentage （EPW） is. However, the increasing trend of EPW will minish quickly when the concentration exceeds 1%. In addition, the longer the process time of ultrasonic is, the higher EPW is. EPW is always higher when the distance between film and ultrasonic transducer is 1/2λ and 3/2λ, and lower when the distance is 1λ, and 2λ,. For 40 nm ZnO particles, EPW of the film effected by ultrasonic with the frequency of 42 kHz reaches the maximum.     

氯化锂对静电纺纳米纤维的稳定长度的影响

选取聚丙烯腈(PAN)/二甲基乙酰胺(DMAC)溶液进行静电纺丝,用添加不同质量分数的氯化锂(LiCl)来控制纺丝液的导电性.理论分析与实验同时表明,在带电射流的运动过程中,含有高含量氯化锂的电势下降比含有低含量氯化锂的要快.前者引起射流的不稳定性提早发生,并且引起射流的不稳定长度减小.     

基于链码的纺织纤维直径测量

首先引入角度链码及其差值等经过改进的链码概念,用以判断纤维交叉和头端,接着介绍边缘平滑的原理和方法.以棉的纵向形态直径测量为例,提出在轮廓跟踪的同时判别纤维交叉和头端的算法;根据棉的纵向形态边缘经平滑后纤维轮廓光滑的特点,提出基于像素长度的纤维直径测量新方法.实际测试表明,对于光滑轮廓的纺织纤维,该算法能够快速准确地测量出其直径.     

低捻转杯纺纱理论分析——阻扭件、阻扭矩及其捻度分布模型

转杯纺纱过程中断头的主要部位在成纱形成过程的一段,此段捻度小、强力低.如果为了扩大转杯纱的应用范围以及改善转杯纱的有关性能,纺制低捻度转杯纱,则断头率进一步提高,生头成功率进一步降低.这里研究在转杯纺加捻区中加装阻扭件后,讨论分析加捻区中纺纱张力的变化,进而构成阻扭件产生的阻扭矩以及形成阻扭件前后区域捻度分布的变化并建立捻度分布模型.理论分析结果表明,加装阻扭件后,成纱捻度不变,但提高了自由端成纱形成过程一段的捻度,这对降低断头率、提高生头成功率有利.     

纱线膨松性能的表征与EIB测试

膨松性能是变形纱线最基本的性能，可用膨松度表征．纱线的膨松度是以纱线空隙率，即纱线体内部纤维间的空隙占纱线整体的体积百分比定义的．实验证明，用Electronic Inspection Board（EIB）检测各类纱线的表观平均直径并计算膨松度有良好的适应性；各类纱线样品膨松度分布于20％～70％之间，以异收缩-空气变形纱和空气变形纱的膨松性最好，以后顺次为毛纱、棉纱、化纤长丝纱．     

静电纺纳米纤维非织造布的热湿传递性能

从静电纺纳米纤维非织造布的空气体积分数出发,研究其热传递性能和湿传递性能,发现静电纺纳米纤维具有优良的保暖性和不良的透湿性.并通过实验得到一定体积分数的纳米纤维非织造布的导热系数,定量描述了纳米纤维非织造布的导热性能.分析了影响透湿性的因素,展望了它在防护性服装应用上的潜力.     

Effects of Steaming on the Tensile Mechanical Properties of Cashmere Fiber

The cashmere yarns were set in steam of 120℃ for 5 minutes after they had been extended to about 3% and wrapped onto the glass mandrels, which was relevant to the industrial setting processes. The effects of the steaming on the tensile mechanical properties of cashmere fiber are investigated. The extension in " yield region" and the extension at rupture of the set cashmere fiber are obviously decreased.