An Analysis of the Bending and Shear Properties of Woven, Double-Knitted, and Warp-Knitted Outerwear Fabrics

Abstract

Mechanical properties of a wide range of commercially-produced outerwear fabrics have been analyzed in terms of the elastic and frictional resistance to bending and shear deformations. The fabrics tested include wool and wool-synthetic blend woven fabrics, wool and textured polyester double-knits, and synthetic warp-knits; some plain single jersey knitted fabrics are also included for comparison purposes Features of the bending and shear deformation and recovery curves such as their shape, asymmetry, linearity, and degree of hysteresis are discussed for each. Finishing has an enormous effect on the bending properties of all the woven fabrics an on the knitted synthetic fabrics, although the effect is less (although still significant) for knitted wool fabrics; the frictional resistance to deformation (in both bending and shear) is always much more critically affected by finishing than is the elastic rigidity of the fabric. Statistical correlations between the elastic and frictional parameters of deformation are explained in physical terms related to the basic fabric construction. Fabric bending properties are shown to depend largely on fabric thickness and other constructional variables, but shear properties show much less systematic variation with such parameters and are largely determined by the type of fabric construction itself. The effect of finishing is also much less for shear than for bending, particularly in the case of knitted structures. The frictional resistance to bending and shear deformations may be used to construct a two-dimensional fabric chart in which each group of fabrics falls into a separate area according to fabric structure and fiber type. This chart may be related to such fabric characteristics as tailorability, drape, and handle.