Velocity accommodation in fretting

This paper is a review of the work done on fretting wear and fretting fatigue in the last few years in Lyon, France. The work is centred around the third-body (interface) and velocity accommodation concepts. After a brief introduction, the paper discusses velocity accommodation between two rubbing solids or first bodies. Results show that the velocity can be accommodated as follows. (1) Without particle detachment through homogeneous bulk elastic deformation cracked bulk elastic deformation surface layer plastic deformation interface crack propagation (2) With particle detachment through slip at the surface within the debris bed or third-body thickness In all the tests run in this programme with different steels, third-body beds afford good protection against fretting crack development or fretting fatigue which is always initiated in the first few hundred cycles. Thus fretting fatigue is controlled by competition between the initiation of damaging surface cracks and the formation of protective third bodies.