Gear contact fatigue is becoming a primary limitation for the growing
demand of power density and service life in gear-driven equipment. The
unchecked surface fatigue crack could further cause premature failure
and put a serious risk to the safety and reliability of mechanical
systems. In this work, an attempt is made to investigate the effects of
rolling-sliding and mild wear on contact fatigue behavior. A
comprehensive contact model is developed to capture the variation
instantaneous pressure and stress field is calculated with the transient
mixed EHL approach. Rolling-sliding contact is simulated with the
time-varying roughness topography updated by Archard wear equation. The
stress cycles are extracted and the relative contact fatigue life is
obtained by using Zaretsky criterion. Results suggest that in
rolling-sliding contact the contact fatigue life is obviously lower
compared with pure rolling. The increases in the number and amplitude of
stress micro-cycles is found to be the main contributors to the
reduction of fatigue life. Mild wear tends to smooth the surface,
subsequently mitigates the stress concentration and reduces stress
cycles, then decrease the risk of surface contact fatigue.