Surface damage prediction during an FZG gear micropitting test

Abstract

A numerical simulation of an actual FZG spur gear micropitting test was performed. The simulation was based on a model that takes into account: overpressure effects due to mixed or boundary film lubrication, in turn caused by the interaction of roughness features of the contacting gear teeth, represented in the simulation by actual roughness profiles measured on the teeth; residual stresses in the gear teeth; a high-cycle, multi-axial fatigue criterion to evaluate the fatigue damage on the surface. The simulation was applied to the four load stages that constitute an FZG gear micropitting test and actual gear meshing was simulated. It was additionally possible to ascertain the adequacy of the model to shorter load durations because the load stages of the original micropitting test had been periodically interrupted for intermediate monitoring.