Research on calculation of contact fatigue life of rough tooth surface considering residual stress

• Innovative research on contact stress calculation and fatigue life calculation of rough gear teeth considering residual stress. • A new method of contact stress and fatigue life calculation of rough tooth surface considering residual stress was proposed. • The influence law of residual stress and rough parameter Sq on the contact stress and contact fatigue life of gear was obtained. • New characteristics of tooth contact performance under the action of initial residual stress and surface morphology were found. Grinding and shot peening produce large residual stresses on the gear teeth. Research on the calculation of contact stress and fatigue life of rough gear teeth considering the residual stress has not been published in the literature. The influence of residual stress and rough surface on contact fatigue is difficult to be ignored, so the research of the paper is of significance. Based on the finite element modeling method of rough surface contact and multiaxial fatigue criterion, the gear contact stress and fatigue life under the action of rough surface and residual stress is obtained. The study found that residual compressive stress can reduce the high stress area of the near-surface and lead to a low-stress area between the near-surface and the sub-surface. In addition, residual compressive stress can reduce the near-surface fatigue failure depth (NFFD) and make the sub-surface fatigue failure area tend to be deeper while increasing the contact stiffness of the tooth surface. The logarithmic value log 10 (2 N f ) of the sub-surface fatigue life is quantitatively related to the roughness Sq and the residual stress amplitude σ rs , and the fitting polynomial of the three variables is obtained, which provides a theoretical reference for the prediction and calculation of the contact fatigue life of the tooth sub-surface.