A stochastic prediction of roughness evolution in dynamic contact modelling applied to gear mild wear and contact fatigue

This study proposes a statistical formulation to depict the evolution of asperity shape induced by wear and plastic deformations under mixed lubrication. The paper develops an asperity strain-hardening model. The complete procedure includes a contact crack initiation prognosis combining multiaxial criteria with a damage accumulation procedure incorporating the load history. The degradation prediction is coupled with a dynamic gear model. A comparison with experimental measurements shows that the roughness prediction of 1.27 μm after 2295 × 103 cycles agrees with the measurement of 1.3 μm. The crack initiation results suggest that micro-pitting and pitting are simultaneous fatigue processes; while micro-pitting originates from the surface, pitting emanates from positions slightly below the surface when surface micro-cracks coalesce with already-weakened sites.