Simplified three-dimensional model for fatigue crack initiation

A computer model based on a simplified three-dimensional model of the micro-structure is defined to simulate the inhomogeneous stress distribution and its influence on multi-crack initiation behaviour in a martensitic steel. The Tanaka–Mura relation for crack initiation is used in this simulation in order to obtain number of cycles to crack initiation in each grain. A continuous crack initiation process is obtained, if the load re-distribution after crack initiation is determined by a finite element stress analysis. Characteristics of the crack patterns obtained with a 3D simulation models are compared with the results obtained with a planar model.