Effect of Different Yarn Combinations on Auxetic Properties of Plied Yarns

Mine Akgun,Fatih Suvari,Tugba Yurdakul,Recep Eren

doi:10.2478/aut-2021-0045

Abstract

Abstract This study presents the effects of a novel plied yarn structure consisting of different yarn components and yarn twist levels on the Poisson's ratio and auxetic behavior of yarns. The plied yarn structures are formed with bulky and soft yarn components (helical plied yarn [HPY], braided yarn, and monofilament latex yarn) and stiff yarn components (such as high tenacity [HT] and polyvinyl chloride [PVC]-coated polyester yarns) to achieve auxetic behavior. Experimental results showed that as the level of yarn twist increased, the Poisson's ratios and the tensile modulus values of the plied yarns decreased, but the elongation values increased. A negative Poisson's ratio (NPR) was obtained in HT–latex and PVC–latex plied yarns with a low twist level. The plied yarns formed with braid–HPY and braid–braid components gave partial NPR under tension. A similar result was achieved for yarns with HT–latex and PVC–latex components. Since partial NPR was seen in novel plied yarns with braided and HPY components, it is concluded that yarns formed with bulky–bulky yarn components could give an auxetic performance under tension.

Highlights

Auxetic materials have a negative Poisson’s ratio (NPR)
As a remarkable case in this study, it could be said that the yarns that have fluctuating changes in the average yarn diameter could yield partial NPRs under tension
NPR was observed in HT–latex and PVC–latex plied yarn with a low twist level

Summary

Introduction

Auxetic materials have a negative Poisson’s ratio (NPR). They expand in the lateral direction under a longitudinal tensile strength and laterally contract when subjected to compressive strength [1, 2].In literature, the auxetic yarn structures that have been reported are the helical structure, semiauxetic structure, and plied yarn structure [3,4,5,6,7,8,9,10,11,12]. Auxetic materials have a negative Poisson’s ratio (NPR). They expand in the lateral direction under a longitudinal tensile strength and laterally contract when subjected to compressive strength [1, 2]. The helical auxetic yarn (HAY) structure was first presented by Hook [11, 13]. The HAY structure is formed by combining two yarn components with different stiffness levels in a double-helical form. The stiff wrap yarn is straightened and displaces the core yarn into a curved shape; as a result of this, the yarn structure is expanded in the lateral direction [11, 13]

Methods

Results

Conclusion