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 eorrodants. 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