47—CLOTH STIFFNESS AND HYSTERESIS IN BENDING

The relation between cloth flexural rigidity and single-fibre flexural rigidity is discussed, and a mathematical formula is derived for the minimum cloth flexural rigidity, neglecting interactions between the fibres; this formula takes account of the twist and crimp in the yarns. An instrument is described which enables the hysteresis in bending of a fabric to be studied; this is of assistance in interpreting the nature of the interactions between fibres, which cause the observed cloth flexural rigidity to exceed the theoretical minimum. The results are given of a detailed study of the bending behaviour of two fabrics; the effect of heat-setting these fabrics is examined.