Crack Process Investigation in Gears Under Single Tooth Bending Fatigue Condition Using Infrared Thermography and 3D XFEM Numerical Models

The present study proposes a combined approach of infrared thermography and 3D XFEM numerical models for crack process investigation in mechanical components such as gears. Over the years, fatigue crack analysis based on energy dissipations in the form of heat generated during fatigue tests has been widely reported, although mainly limited to classical specimens. In this work, this approach is extended to gears under single tooth bending fatigue conditions, where thermal dissipations were acquired using two infrared cameras. Numerical models were developed to investigate the entire crack process, with a focus on both nucleation and propagation. Thermal dissipations, processed in terms of temperature evolution and localized heating, were combined with numerical results and macroscopic fractographies. The analysis, performed on three gear case studies, shows that the crack mechanism can be investigated through thermal dissipations, highlighting asymmetric crack propagation and its evolution when the crack is still internal to the gear.