Study on gear contact fatigue failure competition mechanism considering tooth wear evolution

Contact fatigue issues are becoming more prominent in current gear anti-fatigue designs. Surface wear may result in unavoidable occurrence competition among contact fatigue failure modes such as micropitting and pitting. This work proposed a model incorporating the interface characteristics, mechanical properties and residual stress gradients to explore this competition mechanism during wear process of a wind turbine gear pair. Results reveal that the critical damage position moves deeper from near-surface to subsurface during the wear process, indicating that the most likely failure mode changes gradually from surface initiated contact failure to subsurface initiated contact failure. This illustrates that one-sided gear anti-fatigue designs may not satisfy the complex contact conditions because the dominant failure mode may change during operation.