No abstract

A micromechanical model of the large displacement behavior of a sliver of oriented helical fibers has produced algorithms for predicting and updating all five independent mechanical constants. The incorporation of the micromechanics in a finite-element model of a uniform rope of initially untwisted fibrous material is described. The response of the whole model to combined external and torsional stresses such as occur during twist insertion is then described. A detailed analysis of the stresses and strains in the deformed model shows that fiber packing in the yarn is predicted to quickly become non-uniform. The inner regions become most densely packed, and fibers there are subject to the highest stress levels. Fibers further from the center largely avoid being stressed by moving toward the yarn axis.