A Study on the Bending Properties of Warp-knit Fabrics

Abstract

In the previous paper, an analysis was given of elastic component of the bending property of warp knit fabrics, considering the mechanical properties of yarns in the fabric to be perfectly elastic.In this paper, the bending properties of some fabrics are measured using a pure bending tester designed by Kawabata and then the data are compared with the theoretical calculations. The results show that this theory has enough accuracy to estimate the property, but a little amount of error is observed for the high density fabrics having large number of underlapping.On the base of microscopic observation, some discussions are done for a mechanism in the deformation of knitted structure during bending, proposed in previous paper.It is another purpose of this paper to show how frictional restraint to the bending of the fabric arises. The frictional component is derived from the sum of the frictional resistances among fibers in the bending and twisting of constituent yarns and that between yarns in crossover region. This analysis is found to give a reasonably close prediction of it to the fabrics having loose structure.