Numerical analysis of multiaxial low cycle fatigue of notched specimens made by stainless steel 316L under non-proportional loading

This study analyzes notched specimens made of stainless steel 316L which undergo low cycle fatigue. The specimens were already tested with three different types of load paths and the results were carried out in terms of fatigue life and hardness. The geometries involved feature four types of stress concentration factors. From the pictures of the cracked specimens, the crack initiation spot was detected to be moved from the notch tip. This work evaluates the value and position of local parameters of strain and stress by means of a sophisticated finite element method analysis which described the real material behavior. Other than comparing the crack initiation spot found in the numerical analysis with the one observed in the tests, the model allowed to summarize the fatigue life in a narrow scatter band, giving a reliable design tool and a faithful interpretation of the phenomena involved in this type of load cycle.