Computational model for bending fatigue prediction of surface hardened spur gears based on the multilayer method

•A model is proposed for bending fatigue life prediction of surface hardened spur gears.•Finite element, elastic–plastic correction, and strain-life methods are used.•The multilayer method is employed to model the surface hardened layer.•Surface from subsurface bending fatigue failure is distinguished.•The proposed model is validated against experimental results. A computational model for predicting both the location and the required number of cycles for bending fatigue failure in surface hardened spur gears is proposed. Linear elastic stresses and strains in a single tooth bending fatigue test are corrected for elastic–plastic material behavior. The tooth root region of spur gear is divided into layers. Fatigue properties are assigned to each layer via the hardness method. Based on the multiaxial fatigue criteria, fatigue failure location and corresponding fatigue lives are estimated. Predicted fatigue lives, failure locations, and transition from surface to subsurface fatigue failure show good agreement with the experimental results.