Paper XIV (ii) A Pitting Fatigue Model for Gear Tooth Contacts

A model for the initiation of micro-pit fatigue failure in gear tooth contacts is presented. Micro-pitting is believed to be a surface fatigue mechanism which is highly dependent upon surface roughness and sliding conditions during the tooth contact. The model uses finite element analysis to determine local residual stresses caused by asperity flattening. These are superimposed on gear overrolling stresses and a contact fatigue life model applied. Results show that very large reductions in fatigue life can occur if asperities are plastically deformed during running-in and the contact is sliding during overrolling. Residual stress contours, fatigue life risk maps, and relative life values are given for various asperity sizes and sliding contact conditions. © 1991.