Analysis of Fabric Specimen Aspect Ratio and Deformation Mechanism during Bias Tension

Abstract

Different fabric specimen width/length ratios, called aspect ratios λ are used when bias extension method is applied for woven structure formability evaluation. The aim of this work was to study the influence of λ upon the parameters of fabric specimen’s bias tension. Distinct deformation zones, shear angle and buckling wave propagations as well as critical form stability parameters (critical load Pcr , critical elongation εcr and critical shear angle γcr) were estimated to describe deformation mechanism of the specimen. The analysis of specimen deformations when aspect ratio λ ≥ 2 has shown that with the increase of specimen’s length critical form stability values also increase because of the increased strain distribution uniformity in a central part of a deformed specimen. The concentrated load method was applied in order to study deformation mechanism which is observed between two intersection points of distinct deformation zones without clamping impact. It was found that for longer specimens critical form stability parameters estimated during bias tension were similar to the parameters assessed at concentrated load method. Different specimen behaviour under concentrated load test has proved that the influence of all specimen zones upon critical buckling parameters during bias tension is significant.