On the effect of microplasticity on crack initiation from subsurface defects in rolling contact fatigue

This work demonstrates numerically how microplasticity, i.e. the yielding behavior below conventional 0.2% plastic strain threshold, can lead to initiation of cracks at subsurface defects, in rolling contact applications operating under realistic loads. A 3D elasto-plastic finite element model is employed perform shakedown analysis bearing steel around a small spherical void with two different approximations constitutive micro-strain regime. When non-linear kinematic hardening used fast but smooth onset plasticity, fields strains and micro-residual stresses evolve very distinctly case where sharp transition assumed. To further investigate role tensile occurring former on crack initiation, planar circular inserted equator an entire overrolling cycle investigated by means linear elastic fracture mechanics (LEFM). repeated for sizes respective stress intensity factors their amplitudes, relevant growth, are reported. The also reports implementation details coupling subsequent LEFM model. • Plasticity threshold cannot be neglected. High residual were demonstrated. Cyclic plasticity microscale without unrealistically large Hertzian pressure. Proposed new effective amplitude nonproportional loading.