基于小波和傅立叶变换的纱线波谱图计算

采用离散小波变换与快速傅立叶变换相结合的方法,先对纱线信号进行小波分解,再对各子带信号作快速傅立叶变换,从而得到各子带信号的频谱。截取相应频段,并在同一图形上显示,然后将各频率成分转换成相应的各波长分量,得到纱线波谱图。     

Utilization of the yarn pullout test in estimation of the reserved energy of rib knitted fabrics

The yarn pullout test is a prevailing and particular method to evaluate the effects of yarn properties and the structural characteristics of the fabric on the fabric mechanical performance. In this research, a theoretical model of yarn pull out is presented to determine the reserved energy of weft-knitted fabrics with rib 1 × 1 structure. This model is based on the fabric dimensional properties, i.e. stitch length, wale density, yarn diameter and contact angle of yarns. In order to appraise the proposed model, five different double jersey weft-knitted fabrics with rib 1 × 1 structure were produced and exposed to pullout test. Comparison between deviations of theoretical results from experimental results demonstrates that the presented theoretical model exhibits a rational estimation of the reserved energy in these fabrics.     

Modeling the effects of yarn material properties and friction on the ballistic impact of a plain-weave fabric

Impact of a rigid sphere onto a high-strength plain-weave Kevlar KM2^® fabric was modeled using LS–DYNA^® focusing on the influence of friction and material properties on ballistic performance. Quasi-static friction was experimentally determined and incorporated into the model. Two clamped edges and two free edges were used as boundary conditions to correlate the model to an experimental test providing yarn–yarn movement. Yarns were modeled as continua with modulus and strength dominating along the length. Parametric studies incorporating different yarn material properties and initial projectile velocities were then performed with the above set of boundary conditions. Results indicate that ballistic performance depends upon friction, elastic modulus and strength of the yarns. While friction improves ballistic performance by maintaining the integrity of the weave pattern, material properties of the yarns have a significant influence on the effect of friction. It is shown that fabrics comprised of yarns characterized by higher stiffness and strength relative to the baseline Kevlar KM2^®, exhibited a stronger influence on ballistic performance. Therefore all three parameters viz., friction, elastic modulus and strength along with other variables (fabric architecture, boundary conditions, and projectile parameters) are needed to examine ballistic performance of high-strength fabric structures.     

温敏形状记忆织物的开发及其起拱回复性研究

探讨棉温敏形状记忆聚氨酯包芯纱织物的加工方法及其起拱回复性能。通过分析形状记忆聚氨酯纤维的性能及其作用原理,设计了棉温敏形状记忆聚氨酯包芯纱织物,并将其与纯棉织物和棉氨纶包芯纱织物进行了起拱回复性能的对比试验。试验结果表明,温敏形状记忆聚氨酯包芯纱织物经过热处理后,热回复率高于其他织物,具有良好的形状记忆功能。     

高强碳纤维束丝拉伸性能测试影响因素的研究

研究了3K，6K和12K碳纤维束丝拉伸性能测试过程中的一些影响因素，包括与样品制备相关的胶液浓度、胶液种类、张力、环境湿度以及测试时的拉伸速率。研究结果表明，碳纤维的拉伸性能测试与样品制备及测试过程中的实验条件有很大关系。胶液浓度较低时（〈25％），纤维拉伸强度比正常值偏低。比较了环氧6101和环氧648两种树脂作胶液的情况，前者得到的碳纤维拉伸强度更高。样品固化时施加合适的张力可得到较高的拉伸性能。另外，样品制备时，随着相对湿度的增加，测得的碳纤维拉伸强度逐渐降低。随拉伸速率的增加，碳纤维的拉伸模量逐渐增加。     

纯棉纬弹织物尺寸稳定性的控制

纯棉纬弹织物性能优异，但在染整加工过程中尺寸稳定性不易控制，造成成品门幅不稳定，甚至达不到客户要求，本文基于实验及生产实践，合理选择坯布密度及门幅，正确控制前处理工艺条件，灵活制订后处理工艺路线及工艺条件，既保证外观，弹性伸长率等性能符合要求，又获得满意的纬向尺寸稳定性。     

丝素蛋白腈纶结构性能及其混纺针织纱的开发

通过对丝素蛋白接枝腈 性能及原理的讨论，提出了素蛋白腈纶纤维与天然纤维混纺针织纱及最终产品开发中的技术要点，为丝素蛋白接接腈纶的产品提供了途径。     

转杯纺纺制竹节纱的工艺研究

在改变喂给罗拉速度纺制竹节 的条件下，对转杯纺纺制竹节纱的基本工艺参数进行了理论研究，得到了关于粗节倍数和竹节长度的模型，并通过实验测试验证了理论的正确性，也证明了彩和改变喂给罗拉速度纺制竹节纱的可行性。     

喷气纺纱喷嘴安装位置对成纱强力的影响

研究了喷气纺纱喷嘴安装位置有关参数及解捻管槽数对成纱强力的影响规律。试验结果表明：一级喷嘴与前钳口间距存在临界值，当间距为11mm时成纱强力最高；当两级喷嘴间距为4mm时，成纱强力较高且波最小；异纱钩与二级喷嘴的最佳 间距为88mm，该距离过大过小成纱强力均有降低；随着解捻管槽数的增加，成纱强力提高，实际生是中可选 用四槽。