Mechanics of Elastic Performance of Textile Materials
Mechanics of Elastic Performance of Textile Materials
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纺织材料弹性性能力学
DOI：
10.1177/004051755402401006
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发表时间：
1954
影响因子：
2.3
通讯作者：
W. Hamburger
中科院分区：
文献类型：
--
作者：
M. M. Platt;W. G. Klein;W. Hamburger
本文对决定绳股和股线强度的一些因素进行了定量分析。当与本系列第九部分的分析相结合时，我们就能完整地了解到，在将绳索纤维的强度转化为单股、股线或股线时，以及通过直接投影转化为绳索时，所考虑的各种因素的影响。该问题通过与之前给出的类型类似的力学-统计分析来解决，假设简化的理想几何形式和纱线性能的正态分布。它表明，这样的假设产生的结果，同意，在工程精度的范围内，与实验。支票可用于：不同捻结构的9股绳股，全部由马尼拉马尼拉麻纤维制成;小的虎尾兰3股绳;以及用作实验室模型的马尼拉马尼拉麻纤维的小尺寸束，以说明股线或合股纱线中的单纱数量的影响。数学上分析其机械效应的因素包括：单纱捻度;股线或合股纱捻度;合股的单纱数量;单纱的弹性性能;以及单纱机械性能的均匀性。在将纱线的强度转化为股线和绳索时会发生显著的损失，理论计算和实验验证的效率约为75%。然而，纤维强度转化为股和绳的总转化率低40%的主要原因在于纤维到纱线的转化率低，仅为55%。从纱线到股线的损失表明，导致从低均匀性的纱线断裂伸长率和倾斜的纱线的股线和绳轴，这些影响是相同的幅度为大多数的结构研究。在本工作中所研究的纱线的断裂伸长率的变异系数约为10%，根据其组成纤维的固有变异性为20%-30%，这似乎是加工产生的不均匀性的结果。目前，这种程度的不均匀性不适于通过改变制造技术来显著减少。因此，看来纱线到股线或合股纱线的平移效率的改进实际上只能通过减少股线和绳的捻度或通过使用更可伸长的纤维和纱线来实现。通过与Chow [4]开发的更精确的层状结构几何分析的结果进行比较，检查简化几何分析的结果。两种方法的结果之间的差异被证明是可以忽略不计的扭转结构的实际范围内，证明的假设导致简化的分析。结果，这是图形超过目前使用的绳索结构的变量范围内，立即适用于工程计算的绳索结构，轮胎帘线，缝纫线的强度。适用性的限制是由假设的简化几何的有效性定义的。
This paper is concerned with the quantitative analysis of some of the factors which determine the strength of cordage strands and plied yarns. When integrated with the analyses covered in Part IX of this series [1], a complete picture is given of the effects of the factors considered on translation of the strength of cordage fibers into singles yarns, strands, or plied yarns and, by direct projection, into cordage ropes. The problem is solved by a combined mechanical-statistical analysis similar in type to that given previously [1], assuming simplified idealized geometrical forms and a normal distribution of yarn properties. It is shown that such assumptions produce results which agree, within the limits of engineering accuracy, with experiment. Checks were available for: 9-rope strands of varying twist structure, all made of Manila abaca fiber; a small Sansevieria 3-ply rope; and small size bundles of Manila abaca fiber used as laboratory models to illustrate the effect of the number of singles in a strand or plied yarn. The factors which are analyzed mathematically for their mechanical effects include: singles yarn twist; strand or plied yarn twist; number of singles which are stranded; elastic properties of the singles yarns; and uniformity of the mechanical properties of the singles yarns. Significant losses occur in the translation of the strength of the yarns into the strands and ropes, efficiencies of the order of 75% being theoretically calculated and experimentally verified. How ever, the major cause of the low over-all 40% translation of fiber strength into strands and ropes resides in the low fiber-to-yarn translation of only 55%. The losses from yarns to strands are indicated to result from both low uniformity of yarn elongation to break and inclination of yarns to the strand and rope axes, these effects being equal in magnitude for most of the structures studied. The coefficients of variation of yarn rupture elongation of about 10% for the yarns examined in this work appear, on the basis of the inherent variability of 20%-30% for their con stituent fibers, to be the result of nonuniformities created by processing. Such levels of nonuni formity do not lend themselves, at present, to significant reduction by alterations of manufacturing techniques. Thus, it appears that improvements in yarn-to-strand or -plied yarn translational efficiencies can be practically accomplished only by strand and rope twist reductions or by the use of more extensible fibers and yarns. Results of the simplified geometric analyses are checked by comparison with the results of a more precise geometrical analysis of plied structures as developed by Chow [4]. Differences between the results of the two approaches are shown to be negligible for practical ranges of twisted struc tures, justifying the assumptions leading to the simplified analyses. The results, which are presented graphically over a range of the variables in excess of those presently used in cordage structures, are immediately applicable to the engineering calculations of strength of cordage structures, tire cord, and sewing threads. The limits of applicability are defined by the validity of the assumed simplified geometry.