Force-Extension Behavior of Helically Wrapped Elastic Core Yarns

Abstract

The force-extension behavior of a helically wrapped rubber-like core up to the point of wrap failure has been theoretically analyzed. In addition to the forces required to extend the wrap and core, there is a significant Poisson effect because the wrap applies a radial pressure to the core, particularly at higher helix angles. Agreement between theory and experiment for gum-rubber cores closed butt wrapped with paper tapes was satisfactory, except at high strains where an increasing proportion of the core was no longer covered by the wrap and where the frictional contribution of wrap/core slippage became significant.