Fatigue failure prediction in spur gear pair using AGMA approach

Gears predominantly fail in contact fatigue mode (pitting/spall) due to combined rolling and sliding motion. Pitting initiation has been experimentally investigated by many researchers under different loading and operating conditions. The present work attempts to predict pitting and bending fatigue crack initiation along gear tooth profile using American Gear manufacturing Association (AGMA) design approach. The effect of heat treatment process (Through hardened and Case hardened) on gear fatigue life is also studied. The AGMA results for contact and bending stresses at pitch point are compared with FEA results and a close agreement is observed. The modeling results reveal that increase in load increases the chances of early pitting failure. Case hardening gears delays the pitting initiation on gear tooth surface, while it increases the chances of bending fatigue failure. The pinion addendum region shows better pitting resistance as compared with dedendum region. The highest probability of pitting /bending failure initiation is observed in single tooth contact region due to full load sharing and the chance of contact fatigue failure is more in comparison to bending fatigue failure. (C) 2017 Elsevier Ltd. All rights reserved.