Woven Fabrics Made of Auxetic Plied Yarns.

Wing Ng,Hong Hu

doi:10.3390/polym10020226

Abstract

Auxetic plied yarns are specially constructed with two types of single yarns of different sizes and moduli. This paper investigates how to use these types of yarns to produce woven fabrics with auxetic effects. Four-ply auxetic yarns were first incorporated into a series of woven fabrics with different design parameters to study their auxetic behavior and percent open area during extension. Effects of auxetic plied yarn arrangement, single component yarn properties, weft yarn type, and weave structure were then evaluated. Additional double helical yarn (DHY) and 6-ply auxetic yarn woven fabrics were also made for comparison. The results show that the alternative arrangement of S- and Z-twisted 4-ply auxetic yarns in a woven fabric can generate a higher negative Poisson’s ratio (NPR) of the fabric. While the higher single stiff yarn modulus of auxetic yarn can result in greater NPR behavior, finer soft auxetic yarn does not necessarily generate such an effect. Weft yarns with low modulus and short float over the 4-ply auxetic yarns in fabric structure are favorable for producing high NPR behavior. The weft cover factor greatly affects the variation of the percent open area of the 4-ply auxetic yarn fabrics during extension. When different kinds of helical auxetic yarns (HAYs) are made into fabrics, the fabric made of DHY does not have the highest NPR effect but it has the highest percent open area, which increases with increasing tensile strain.

Highlights

IntroductionPoisson’s ratio (PR) is defined as the negative ratio of the transverse strain to the extension strain
Poisson’s ratio (PR) is defined as the negative ratio of the transverse strain to the extension strain.It is one of the fundamental properties of fabrics which can be used to determine their applications based on the deformation behavior under tensile loading
When different kinds of helical auxetic yarns (HAYs) are made into fabrics, the fabric made of double helical yarn (DHY) does not have the highest negative Poisson’s ratio (NPR)

Summary

Introduction

Poisson’s ratio (PR) is defined as the negative ratio of the transverse strain to the extension strain It is one of the fundamental properties of fabrics which can be used to determine their applications based on the deformation behavior under tensile loading. Researchers found that conventional fabrics have positive PR and become narrower when stretched, and investigation was further extended to explore the reasons behind such behavior. Shahabi et al carried out a very detailed investigation on the effect of crimp on the contraction of worsted fabrics under tensile loading [4]. Crimps exist in both warp and weft yarns due to interlacement. When the fabric is extended in one direction, the yarns in the loading direction are straightened and their crimp reduces until it reaches zero. It was found that the underlap length of loop imposes the most significant effect on the PR of the warp-knitted fabric [5]

Objectives

Methods

Discussion

Conclusion