Mechanism of fretting fatigue in steel cables

Abstract This paper presents a detailed account of the different mechanisms of interwire fretting fatigue that operate inside steel cables under different modes of external cyclic loading. Based on previously reported theoretical and large-scale experimental observations, an insight is given into the pattern of interwire/interlayer contact forces and the associated relative displacements in practical large-diameter spiral strands. Both axial and free bending loadings are addressed, and the differences between their associated mechanisms of interwire fretting fatigue are identified. It is suggested that single (or twin) wire fretting fatigue experiments should be carried out under realistic modes of interwire movements and ranges of normal loads, representative of the conditions inside steel cables. To this end, some straightforward formulations are given, which provide simple means of obtaining sensible values for the ranges of relative movements and normal forces to be used in such experiments.