Multiaxial Fatigue Criteria Applied to Contact Fatigue of Surface-Treated Gears

摘要

A numerical model was developed to predict residual stress relaxation and to estimate the most probable site of contact fatigue crack initiation, using multiaxial fatigue criteria. The model was applied in the study of carbo-nitrided and shot-peened steel gears from an automotive gearbox submitted to contact fatigue. The X-ray diffraction technique was used to study the evolution of residual stresses as a function of gear damage. An experimental method combining the X-ray diffraction stress analysis and the electric resistance strain gauge technique was used to determine the mechanical characteristics of the surface-treated layers. The Dang Van multiaxial fatigue criterion was used to estimate the most probable depth of contact fatigue crack initiation, taking account of the influence of residual stresses, roughness and friction.