Damage behavior due to rolling contact fatigue and bending fatigue of a gear using crystal plasticity modeling

Gear fatigue issues, including bending and contact fatigue, are attractive problems with significant engineering safety implications. Currently, no fatigue analysis model can combine the effects of bending and contact fatigue to predict gear fatigue life because of their different failure mechanisms. In addition, most gear fatigue studies are still limited to the understanding at the macro level, thus cannot provide theoretical interpretations for practical engineering observations such as scattered experimental data and material deterioration. Here, we proposed a unified microstructure model by considering different failure mechanisms of rolling contact and bending fatigue. The crystal plasticity model combing the multiaxial fatigue criteria was established to capture the stress-strain history at the microlevel. The deterioration of mechanical properties of the material was simulated based on the continuum damage theory. This work provides more insight into the physical understanding of gear fatigue failure mechanism and theoretical support for gear antifatigue design.