Stress-Strain Relationships in Yarns Subjected to Rapid Impact Loading

Abstract

Stress-strain curves at rates of straining up to 440,000%/min. have been obtained for a number of textile yarns by a technique involving high-speed photography of the yarn following transverse impact. These curves and others obtained at conventional speeds are presented for samples of acetate, triacetate, cotton, polyester, glass fiber, human hair, vinal, nylon, acrylic, rayon, saran, and silk yarns. Also given are specific breaking energies obtained from the areas under the stress-strain curves and by direct measurements involving longitudinal impact speeds of the order of 50 m./sec. These data show how stress-strain curves depend upon rate of straining and provide ratings for the yarns with respect to ability to survive impact and to resist impact without appreciable deformation.