Empirical equations and poisson's ratios for initial loadextension properties of some complex glass and aramid technical weft knitted structures

Kurbak A., Öztürk S.

Tekstil ve Muhendis, vol.26, no.116, pp.381-405, 2019 (Scopus) identifier

  • Publication Type: Article / Article
  • Volume: 26 Issue: 116
  • Publication Date: 2019
  • Doi Number: 10.7216/1300759920192611611
  • Journal Name: Tekstil ve Muhendis
  • Journal Indexes: Scopus, TR DİZİN (ULAKBİM)
  • Page Numbers: pp.381-405
  • Keywords: Aramid fiber, Contraction, Empirical equations, Glass fiber, Initial contraction rates., Initial extension rates, Load-extension, Weft knitted fabric
  • Dokuz Eylül University Affiliated: Yes


© Chamber of Textile Engineers.This work builds on former research carried out concerning load-extension properties of plain knitted glass technical fabrics. In related former research, it was determined that a load-extension or a load-contraction curve could be considered in three stages of extension or contraction. These stages were a) the extension or contraction of the fabric (the first stage), b) the extension of the yarn along with the change of the shape of the sample (the second stage), and, c) the extension or contraction of the fibres (the third stage). In the same works, theoretical analyses were then provided to explain the first stage of extension or contraction, and thus some simple equations between load and extension and between load and contraction together with Poisson's ratio were obtained. In obtaining the extension of the loop head curve, the equation of extension of a circular ring had been applied. This formulation enabled the emergence of a method that separates the frictional restrains and/or fabric jamming forces from the experimentally obtained quadratic curve fittings for plain knitted fabrics. Building on those former studies, for the present work, similar experimental studies for the first stages of extensions or contractions, were carried out for some more complex technical weft knitted structures that use E-glass and Aramid yarns. The curve fitting equations are obtained and some empirical equations are given, assuming that the same method of separating frictional restrains and/or fabric jamming forces from quadratic curve fittings also applies for complex structures. Extension and contraction rates are also calculated and discussed further. These empirical equations can, of course, be used in related engineering software.