Effects of Manufacturing and Installation Factors on the Initiation and Propagation Characteristics of Bending Fatigue Crack in Spur Gear

Root bending fatigue is the main cause of root crack formation, and the crack initiation and propagation process is also influenced by factors such as tooth surface morphology, manufacturing, and assembly. In order to address the short-comings of existing research on crack initiation and propagation in root bending fatigue, this study establishes a finite element model for crack propagation in root bending fatigue guided by experimental results based on linear elastic fracture mechanics principles. The effects of surface roughness and center distance variation on the crack propagation process are considered and validated. The research shows that the crack initiation location and initial propagation direction are not affected by changes in the load magnitude. Surface roughness and center distance factors have a significant influence on the stress intensity factor during the crack propagation process, thereby affecting the crack propagation rate and trajectory.