Microstructure-sensitive modeling: Application to fretting contacts

The size of the deformation and damage fields produced by fretting are of the same scale as the microstructure. Therefore, a microstructure-sensitive modeling approach is needed to study the influence of the microstructure on the fretting behavior. This study is aimed at evaluating the dependence of normal force and tangential force amplitude on the drivers for fatigue crack formation. Previously, fretting maps were developed for Ti–6Al–4V using a two-dimensional crystal plasticity model to identify the conditions leading to elastic shakedown, surface plasticity, and subsurface plasticity in the partial slip fretting regime. In this study, more realistic three-dimensional crystal plasticity constitutive relations are used to describe the deformation behaviors of the primary α and α/β lamellar phases of Ti–6Al–4V at room temperature. In addition, fully three-dimensional finite element simulations are conducted. The new simulations substantiate the results of the previous 2D modeling in that the distribution of plastic strain is highly heterogeneous and ratcheting is the dominant component of the regions within the field where most of the plastic strain accumulates. The relative dependence of the fretting loading parameters on fatigue crack formation is determined using a ratcheting-based critical plane fatigue parameter.