Fretting in Steel Ropes and Cables — A Review

The numerous inter-wire contacts in ropes and cables are potential sites for nucleation of fatigue cracks by fretting. At larger amplitudes of movement excessive wear can occur leading to decreased cross-section of a wire and increased stress, or if debris accumulates, forcing apart of the wires. In locked coil ropes this can cause local stiffness and ingress of corrodants. The wires themselves have an asymmetric residual stress distribution circumferentially resulting from the drawing process. The position of an inter-wire contact relative to this greatly influences the fretting fatigue strength. Hot dip galvanising reduces these stresses as well as giving cathodic protection. Local friction is reduced by incorporating a lubricant in locked coil ropes. Conventional grease-based lubricants with high shear strength are most effective in reducing friction but recent experiments with a lower viscosity oil containing graphite show promise