The dimensional change of fabrics during the wear is one of typical fatigue phenomena, which is called as “Bagging”. In order to give basic data for fatigue prediction, the dimensional change of double knitted fabrics is studied and discussed in relation to the change of other mechanical properties which was studied in the previous paper. The distortion and the recovering process after the cyclic shearing deformation under a constant extension are measured and analyzed by the same exponential approximate as in the previous paper, where α
l, β
l and
T0 are the dimensional residual value, recover value, and the recovering time constant respectively.
Following results are given by these parameters:
1) The residual value α
l shows an increase with the increasing of deformation repeating times
n, and recovered ratio (β
l/α
l+β
l) represents well the advance of fatigue phenomena.
2) The difference of dimensional recovering properties can be observed between fabric of Pontide-Roma structure and those of Interlock structure.
3) Worsted double knitted fabrics show less amount of α
l than that of textured fabrics.
4) Residual extension amount can be related to the hysteresis of shearing and tensile properties of undeformed fabrics.
View full abstract