Automotive industry and fatigue design

The fatigue assessment of automotive parts is based on a reliability approach taking into account the variability of the car usage and the fabrication scatter. At the design stage, the service loading is processed using a cumulative damage method to provide a constant amplitude equivalent damage loading. The fatigue assessment calls for two types of fatigue criteria : high cycle fatigue criteria for components which are working in elasticity like chassis parts or crankshafts, specific tools are used for welded structures - low cycle fatigue criteria for component which may sustain inelastic strains such as cylinder heads or exhaust pipes. The methods used are illustrated with examples in the following.