Evaluation of cyclic inelastic response in fretting based on unified Chaboche model

Fretting in high strength metalline materials is one of primary failure mechanics that reduces the structural integrity of engineering component. The cyclic deformation response in the region experiencing fretting plays a central role. A unified cyclic viscoplasticity Chaboche model at finite deformations that incorporates fully explicit contact analysis is used to investigate the plastic strain history in fretting process. The analyses are accompanied by finite element simulations using a non-linear kinematic hardening rule with isotropic cyclic hardening and the full details of contact behavior are solved for at all stages of the loading. Numerical evaluations have explored the nature of subsurface cyclic plasticity and interface contact stress fields for realistic fretting fatigue geometries for an applied bulk stress amplitude with a stress ratio of R=−1, two tangential loads, and two different values of coefficient of friction. The characteristics of the fretting fatigue, including local cyclic stress strain and cumulative plastic strain are all better described. Owing to the fact that the plastic anisotropy in the scale of grain size plays a significant role especially in the very local region near the contact edge, an analysis of plastic anisotropy is presented in fretting problem. In the case of fretting configuration considered here, the plastic history combines cyclic plasticity and plastic ratcheting when plastic anisotropy is considered, while the ratcheting plasticity dominates during the fretting process without consideration of plastic anisotropy.