Tooth Interior Fatigue Fracture - computational and material aspects

The hypothesis of the gear failure mode Tooth Interior Fatigue Fracture (TI FF), i.e. a fatigue crack is initiated in the interior of the tooth, is ana lysed by numerical simulations using FEM and the critical plane fatigue ini tiation criterion according to Findley. The residual stress profile in the gear is simulated and calibrated versus a neutron diffraction residual stre ss measurement. Fatigue properties are determined experimentally and are ta ken to vary with depth in the numerical analysis. In addition, the effect o f shot peening is included. The analysis shows that a TIFF-crack is initiat ed approximately mid-height of the tooth and slightly below the case-core b oundary. Furthermore, the analysis shows that TIFF is more pronounced in id lers than in single stage gears. (C) 2001 Elsevier Science Ltd, All rights reserved.