Internal Friction due to Wire Twist in Bent Cable

Abstract

A static and a quasi‐static cyclic bending of a cantilever cable is considered in order to investigate the friction losses in cables. It is assumed that slippage due to twisting of wires is a source of internal friction. Slippage takes place within finite segments along the wire. It starts near the clamp and then propagates along the cable with the increase in load. The load‐deflection characteristic becomes essentially nonlinear after the load exceeds some critical magnitude below which there is no slippage. Two types of hysteretic loops are investigated: (1) Local, characterizing losses in a wire cross section; and (2) global, associated with the point of load application. It is shown that the local loop is symmetrical and closed and that a unique correspondence exists between a load versus twisting characteristic of a wire in a simple bending and friction losses in this cross section in a cyclic bending. Similar correspondence between global characteristics of a cable is introduced. Numerical results for a one lay cable are given.