FEM modeling of crack nucleation and crack propagation fretting fatigue maps: Plasticity effect

Fretting fatigue life is a strategic issue for modern industries. Various strategies have been proposed to predict finite endurance fretting fatigue behavior. For long term assemblies, « infinite » endurance is preferred. This concept was rationalized using a so-called fretting-fatigue map which plots crack nucleation and crack arrest boundaries as functions of fatigue stress and fretting force. This mapping concept was established experimentally coupling plain fretting, fatigue and fretting fatigue experiments. It was also simulated using FEM elastic simulation. The correlation was good as long as elastic stress conditions were imposed. However, once significant plastic deformation was generated in the contact the elastic prediction induced a significant discrepancy. In the frame of this work we investigated how the integration of plasticity in the modeling strategy could improve respectively the crack nucleation and crack arrest boundaries predictions. The influence of plastic deformation on contact pressure profiles and the role of residual stresses were discussed.