Dr. Jochen Witzig
Dr. Jochen Witzig is responsible for the development of transmission systems in buses at ZF Friedrichshafen. Previously he was a researcher at FZG. (Bio last updated 2018-02-08 Contact Randy Stott, Managing Editor, with changes.)
Articles by Jochen Witzig
- Tooth Flank Fracture - Basic Principles and Calculation Model for a Sub-Surface-Initiated Fatigue Failure Mode of Case-Hardened Gears (August 2015)
Cracks initiated at the surface of case-hardened gears may lead to typical life-limiting fatigue failure modes such as pitting and tooth root breakage. Furthermore, the contact load on the flank surface induces stresses in greater material depth that may lead to crack initiation below the surface if the local material strength is exceeded. Over time the sub-surface crack propagation may lead to gear failure referred to as â€śtooth flank fractureâ€ť (also referred to as â€śtooth flank breakageâ€ť). This paper explains the mechanism of this subsurface fatigue failure mode and its decisive influence factors, and presents an overview of a newly developed calculation model.