Investigation of fretting fatigue behaviour under multiaxial non-proportional loading

Fretting fatigue is a structural mechanism observed when two contacting bodies are subjected to an oscillatory loading. The study on fretting fatigue behaviour of 60Si2Mn steel was conducted under condition of multiaxial non-proportional loading. The fretting fatigue lives corresponding to different cyclic axial stress amplitudes were tested with same rotation loading amplitude and contact normal pressure. The characters of frictional and wear surfaces and fracture morphology were analysed in detail by scanning electron microscopy and optical images. It is found the fretting fatigue life decreases but the work done by axial frictional force increases with the increase of the axial stress amplitude. Fretting fatigue crack initiates near the trailing edge of fretting contact zone and propagates at an angle of 45 degrees along the axial direction at the existence of tangential shear stress produced by the rotation loading. Apparently, the fracture surface is not smooth and perpendicular to the axial direction of specimen.