A lubrication contact pair model for simulating gear micro-pitting damage characteristics based on contour integral

Abstract

A new two-dimensional finite element model of a lubricated contact pair, based on a contour integral, is proposed to investigate the formation of micro-pitting on gear tooth surfaces. Meanwhile, the contact properties and elasto-hydrodynamic lubrication (EHL) conditions of the gears are considered in the lubricated contact pair model. Then, the stress intensity factors (SIFs) KI and KII and the propagation angle θ C at the crack tip are analyzed by ABAQUS software. Next, the equivalent SIF Kσ can be calculated according to the maximum tangential stress (MTS) criterion, which is often used as the criterion for crack propagation. Considering the effect of a moving contact, the crack more easily propagates under the load x0/ b = −0.895. Furthermore, the pit shapes and variation of stress intensity factor are determined for various combinations of initial crack length a0 and angle β. The results show that longer germinated cracks propagate in areas that are deeper below the tooth surface. And the total length of final crack increases with the initial length and germination angle. These research results provide theoretical support for contact fatigue life analysis and meshing stiffness calculations of micro-pitting gears.