纱条中纤维的分布对其不匀率影响与检验方法

纱条中纤维的分布对其不匀率影响与检验方法棉纱的重量不匀率是衡量其质量优劣的重要指标之一。棉纱条中纤维的组成结构，如纤维平均长度，长短纤维比例，以及排列状态等都对纱条不匀率有影响。所以，可以经过其抽样检验法，了解、掌握纱条中纤维的分布情况。并进一步分析...     

生条中纤维左头端的分布

为进一步探究纱条中纤维的分布规律,模拟纱条中纤维的排列情况,对纤维左头端沿纱条轴向服从均匀分布的假设进行实验验证。通过示踪纤维的方法测定若干给定长度的生条片段中染色纤维的左头端数,并利用χ~2拟合检验法对所测数据进行检验。结果表明:生条中纤维左头端沿生条轴向服从均匀分布的假设是合理的;通过改变染色纤维的几何特征、种类及所取生条的片段长度考察了对纤维左头端数的影响,证明了所取生条的片段长度对纤维左头端沿生条轴向服从均匀分布的结论没有显著影响,最终为预测纱条的性能提供了基础。     

牵伸对纱条条干不匀影响的模拟研究

牵伸时纤维运动引起其排列变化是影响牵伸后纱条条干不匀的关键.为探究纤维变速点分布对牵伸后纱条条干不匀的影响,通过计算机模拟了实际纱条中的纤维排列(实际纱条),分别对理想纱条和实际纱条牵伸过程中的纤维运动进行了模拟,计算了在不同变速点分布下牵伸后纱条的条干不匀,并进行实验验证.结果表明:与理想纱条相比,实际纱条的条干不匀...     

纱条不匀预测模型的优化

本文采用菲波纳齐法和黄金分割法快速寻求合适的背景值，对纱条不匀的预测模型进行了优化，为纱条不匀的预报提供了更加精确的数学模型。     

纱条不匀灰色预测模型的建立

应用灰色预测理论,对纱条不匀进行预测,建立了纱条不匀灰色预测模型,并对该模型精度检验,为纱条不匀的预测与控制提供了精确的数学模型。     

纱条不匀的混沌特性

根据非线性动力系统理论 ,对纱条不匀数据中的混沌特性进行了分析 ,在对其不匀序列进行相空间重构的基础上 ,通过对关联维数的逼近及最大李雅普诺夫指数的计算 ,得出在所分析的棉条不匀序列中 ,存在混沌现象。     

基于纤维排列参数的纱线不匀预测

在某一纱条结构假设下,提出一种新的纱线细度不匀模型——纤维通道重排假构模型,并给出了既反映纱条截面纤维根数,也反映纱条纤维长度的纱条不匀程度的表征参数——纤维通道内间距。然后利用Martindale极限不匀率公式的原理,进一步给出这个模型的特征分析和各个参数之间的统计分析;最后在实验数据分析的基础上得到了预测的经验公式,并在已知纤维长度参数、纱线截面纤维根数的情况下,预测了纱线的条干不匀,预测结果的精度较高。     

也谈毛纱截面内的纤维根数

与传统的计算方法不同，本文用六方密堆积结构导出了毛纱截面内的纤维根数及其可纺支数之间的计算公式。     

基于相空间重构的纱条不匀预测

 东华大学机械工程学院 上海200051     

纱线条干不匀的随机模拟

 纤维随机排列的描述是研究纱线不匀理论的关键。给定一个纤维长度分布,如果假设纤维头端在纱线长度方向服从均匀分布,便可以建立理想纱条中纤维排列的几何模型。采用Monte Carlo方法模拟了这个理想纱线截面纤维根数的变化。在纱线的几何模型中,还使用8毫米的检测区域模拟了电容式条干仪的检测结果。通过比较说明,在纤维随机排列的前提下,随着纱线支数的增大,纱线模拟检测 值必然按照某个规律增大,理想纱条的截面纤维根数渐近服从正态分布,纱线截面的纤维根数变异与模拟检测的区间上纤维量的变异相关性不够显著。纱线实测数据说明了模型的有效性。     

A new approach to theoretical yarn unevenness: a binomial distribution model

For many decades, Martindale’s theory on yarn unevenness has been widely used as a reference for staple yarn production and its quality control. With the yarn count becoming higher and higher and with the decrease in the yarn irregularity, the index of irregularity (I), defined on the basis of Martindale’s limit yarn unevenness, could not be used as a fully effective yardstick for evaluating the yarn unevenness caused by a specific spinning process. This approach, under some plausible assumptions, constructs a new model with a binomial probability distribution that describes the status of the fiber array in a yarn. The analysis of the model is done with the simulation of the parameters and the calculation of cotton ring‐spun yarns is conducted. A newly defined parameter, δ, proves to be valid for evaluating the change in the number of fibers in a cross‐section of the yarn. This parameter, which describes the variation in the number of fibers, can be used as a fiber alignment index in assessing the yarn irregularity in terms of the change in the number of fibers in its cross‐section. The new model can serve as a semi‐empirical method for forecasting the yarn unevenness.     

Simulation on yarn strength based on fiber random arrangement in the yarn

Many models have been established to describe yarn strength, but the existed strength expressions are complicated and can only describe yarn strength qualitatively. In this study, a method of yarn strength simulation is proposed to observe the effect of fiber length on yarn strength. A yarn segment with certain length of fiber is firstly simulated according to fiber random arrangement in the yarn, and yarn strength can be calculated by identifying fiber slipping or breaking in the yarn breaking section. It can be seen from the calculated values that yarn strength grows gradually with the increase of fiber length, and decreases with the increase of critical slipping length. In addition, the changing tendencies of simulated yarn strengths with different fiber lengths are coincident with the tested values. Therefore, this method is reasonable and could quantitatively reflect the influence of fiber length on yarn strength.     

原棉性能与纱线强力的关系

介绍原棉性能对纱线强力的影响 ,并通过实验探讨棉纱强力与棉纤维线密度、短绒率、天然转曲数之间的关系 ,为合理使用棉纤维提供了理论依据。     

Simulation on fiber random arrangement in the yarn part II: joint effect of fiber length and fineness distribution

Simulation on fiber random arrangement in the yarn has been studied in our previous research, where only fiber length distribution was considered. In this study, fiber fineness distribution was also taken into account in order to study the joint effect of fiber length and fineness distribution on fiber arrangement in the yarn. Eight-millimeter term limit irregularity of simulated yarn can be re-expressed by calculating the irregularity of the total weight of fibers within each yarn subsection. It can be seen from the results that the calculated irregularities considering fiber fineness distribution are closer to tested values compared with those without considering fiber fineness distribution. Besides, when the variance of fiber fineness gets greater, the difference between the calculated values with and without considering fiber fineness distribution becomes more obvious. For fiber length, the effect of average fiber length on yarn limit irregularity is very little, while its distribution has no significant effect on yarn limit irregularity. The improved simulation on fiber random arrangement in the yarn is more reasonable and can be applied for the prediction of yarn qualities.     

Effects of fiber types and blend ratios on Murata Vortex yarn properties

Murata Vortex spinning (MVS) system is one of the unconventional systems for yarn manufacturing. It is suitable for spinning of 100% cotton fibers, synthetic fibers, and cotton/synthetic fiber blends which are 1 inch or more in length. The production ranges are between Ne 15-60. Vortex yarn and fabrics have low hairiness, clear appearance, high resistance to pilling and abrasion. In this study, the vortex yarns with Ne 30 are produced in different blend ratios in Murata Vortex Spinner using carded cotton, viscose, modal, silver-added polyester (Flexsil-D2?), polyester, and nylon 6.6 fibers. Vortex spun yarns are tested to determine the yarn properties which are diameter, density, roundness (shape), unevenness, imperfection, Uster hairiness (H), Zweigle hairiness, tenacity, and elongation. The study reveals that the fiber type has quite significant effects on yarn properties. In terms of structural properties, cotton is the most negative fiber while regenerated cellulosic fibers are the most positive. As modal, nylon and polyester fiber increase yarn strength, nylon and viscose fiber increase breaking elongation. Viscose and modal reduce unevenness, imperfection and hairiness while polyester and nylon exhibit more negative effect on these properties.     

组织结构对UHMWPE短纤纱织物防刺性能的影响

UHMWPE短纤纱具有优秀的抗切割性与较好的树脂浸润性,非常适用于制作防刺材料。文章试织了12种不同织物规格的试样,进行准静态穿刺实验,探究5种因素(组织、紧度、纱线线密度、经纬密和面密度)对织物防刺性能的影响,并比较不同穿刺角度下织物防刺性能的差异。结果表明:与方平织物与接结双层织物相比,平纹织物的防刺性能最好;同种经纬密或同紧度下,粗特纱织制的平纹织物防刺性能好;随着经密增加,紧度增加,面密度增加,防刺性能逐渐增加,但织物过于紧密时,防刺性能反而降低;平纹织物的穿刺性能具有各向异性,经纬向的防刺性能优于45°方向。     

纤维的长度特征对成纱的影响

为探讨纤维长度对纺纱过程和成纱质量的影响,通过理论分析以及对一系列实验结果的分析和总结发现:在纺纱过程中,纤维长度不仅影响加工工序的选择,而且影响最终的成纱质量.由于纤维在纱条中呈随机排列,过长的纤维会导致成纱均匀度恶化,并对纺纱过程有负面作用;而太短的纤维会在一定程度上影响纱的强力.因此,选择长度适当的纤维可以兼顾纺纱和成纱综合质量.     

海岛型复合纤维与高收缩纤维混纤网络丝的应用

对海岛型复合纤维与高收缩纤维混纺网络丝的应用进行了研究.混纤网络丝经热湿处理,高收缩聚酯长丝产生高收缩而处于芯层,超细纤维分布在表层,从而使网络丝具有优异的蓬松丰满和柔软细腻的特性,并采用缎纹组织结构,设计开发了新型织物.通过对其风格特征和主要性能,如柔软度、悬垂性、透气性、抗皱性及抗静电性等的测试分析,结果表明,所开发的织物具有柔软悬垂、光泽优雅、手感细腻的桃皮绒新风格.     

珍珠纤维性能及其混纺竹节纱开发

简要说明了珍珠纤维的性能,介绍了珍珠纤维/棉纤维/粘胶纤维混纺竹节纱的纺纱工艺配置,阐述了在环锭细纱机上生产珍珠纤维/棉纤维/粘胶纤维混纺竹节纱的方法,测试了成纱质量,并进行了理论分析,指出了生产过程中应该注意的问题。