A Device for Measuring Stress-Strain Behavior of Low-Modulus Textiles Under Uniform Radial Straining1

Abstract

This paper describes a strain tester that stretches a knitted fabric or other low-modulus material such that the strain at any point in the specimen is uniform in any planar direction. Radial strain is produced by expanding the perimeter of a circular sample radially. Uniform radial strain is of interest in testing the effects of chemical or other treatments on knitted materials which undergo minimal yarn-loop sliding during use. The apparatus is attachable to a standard tensile tester which records the cumulative stress-strain curve. Force-deformation curves and unrecovered-strain data are given for three patterned jersey knits.