Numerical simulation of micro-crack initiation of martensitic steel under fatigue loading

This paper deals with the initiation of small cracks in a martensitic steel under low cycle fatigue loading. A representative volume element (RVE) of the polycrystalline material is generated using a Voronoi tessellation. Heterogeneous stress distributions are calculated with the finite element method. The number of cycles to crack initiation is estimated on the basis of the Tanaka-Mura model. The simulation model yields a relationship between the crack densities and the number of load cycles as well as the crack initiation rate. For all strain ranges considered, the simulation results agree well with the experimental data.