StressLifetc – NDT-related assessment of the fatigue life of metallic materials

Weight-optimized component design as well as a reliable estimation of the lifetime of metallic materials and components requires a comprehensive understanding of fatigue processes and a systematic investigation of the underlying fatigue behavior. Therefore, nondestructive testing methods, digitalization of measurement techniques as well as signal processing can be combined with a short-term procedure in order to acquire potentially more information about fatigue processes, while experimental effort and costs are reduced significantly. This leads not only to considerable advantages over conventional methods for determining S-N curves, but also over established short-term procedures, due to the possibility of applying this information from just a few specimens to attain fatigue life calculations. The StressLife approach is a new short-term calculation method which considers the nonlinear relation between the elastic, elastic-plastic and plastic portion of the material response in the deformation process. Within the scope of the present work, the change in temperature of SAE 1045 (C45E) specimens was measured during fatigue tests via an infrared camera in order to feed the thermal response back into the new StressLife approach for a reliable fatigue life calculation.