Upon Fretting Behaviour in a Hertzian Point Contact

Abstract

Fretting is known as a wear process occurring in a small amplitude cyclic motion of two solid contacting surfaces and it can affect the fatigue resistance of the material, inducing wear and cracking. The kinematics characteristics of movement yield to an interfacial micro-slip situation frequently encountered in industry due to machine vibrations, cyclic load, cyclic accelerations, cyclic stresses, acoustic noises or thermal cycling. Under cyclic normal or tangential loadings of a sphere on plane contact, common features were found. In both cases of tangential and radial fretting, the contact area is divided into two main zones: a central stick zone surrounded by an annular micro-slip region. In the centre, where the interface of the two bodies kept contact all the time, no damage was detected. The wear zone was located in the micro-slip zone. The deformation behaviour of different contact materials strongly depends on the loading speed, due to different rate-sensitive behaviour of materials