Influence of the grain size on the fatigue initiation life curve

This study is dealing with the effect of the grain size on the fatigue lifetime of metallic components, which is represented in the form of (S-N) Wöhler curves of two different grain sizes. The micro-models containing the microstructures of the two different grain sizes are handled by employing the Finite Element Method (FEM) and the required number of cycles for crack initiation was calculated by using the physically-based Tanaka-Mura model. By implementing the different grain sizes in the micro-model, the effect of the grain size on the fatigue life and especially on the endurance limit, in the form of the S-Nini diagram, can be obtained.