MECHANICAL-PROPERTIES OF TWISTED FILAMENTS

The knowledge of some mechanical properties of twisted filament is necessary to predict properties of continuous-filament yarns. Retraction, strength, strain, and elastic properties of filaments are the chief characteristics. Assuming that the filament can be considered as a yarn made of fibers bounded together and then twisted, formulas for prediction of those properties were elaborated and then compared with the experimentally received values. The results obtained in testing the mechanical properties of the discussed filaments and bifilaments are compared with results of mathematical analysis. It is shown that the strength of twisted filaments decreases with increasing twist, and comparison of the experimental and the calculated results implies that a decisive part is played here by material creeping in the final stage of stretching. In twisted filaments, the elongation at break increases with higher twist.