Mode I stress intensity factors for curved cracks in gears by a weight functions method

Abstract

The most recent trend in power transmission design considers the damage‐tolerant approach as one of the methods to obtain safe, reliable and light systems. This means that components containing cracks must be considered and analysed to understand the conditions that cause critical cracks and defects and their dimensions.In this paper a cracked tooth of an automotive gearwheel is considered. A numerical procedure (based on the slice synthesis weight function method) to calculate the stress intensity factors of curved cracks due to bending loads is illustrated. The results are compared with those obtained by expensive finite element calculations. The agreement is satisfactory and the proposed technique proves to be very attractive from the point of view of time saving.One example of an application to fatigue design practice is provided, namely the analysis of fatigue crack propagation in surface‐treated gears. The results show the role played by residual stresses induced by carburizing and shot peening.