Fretting fatigue crack initiation lifetime predictor tool: Using damage mechanics approach

Fretting fatigue is a combination of two complex mechanical phenomena. Fretting appears between components that are subjected to small relative oscillatory motions. Once these connected components undergo cyclic fatigue load, fretting fatigue occurs. In general, fretting fatigue failure process can be divided into two main portions, namely crack initiation and crack propagation. Fretting fatigue crack initiation characteristics are very difficult to detect because damages such as micro-cracks are always hidden between two contact surfaces.In this paper Continuum Damage Mechanics (CDM) approach in conjunction with Finite Element Analyses (FEA) is used to find a predictor tool for fretting fatigue crack initiation lifetime. For this purpose an uncoupled damage evolution law is developed to model fretting fatigue crack initiation lifetime at various fretting condition such as contact geometry, axial stress, normal load and tangential load. The predicted results are validated with published experimental data from literature.

► Damage mechanics principle was used to model fretting fatigue crack initiation life.
► Damage mechanics approach was used to find the location of initial crack.
► Proposed model takes into account the effect of stress triaxiality.