Effect of Some Parameters on the Plastic Fatigue Behavior with Micromechanical Approach

The fatigue life and the micro-damage heterogeneity for FCC polycrystalline metals are qualitatively evaluated employing a coupled phenomenological micro-mechanical model of the early plastic fatigue damage initiation. This model is based on the slip theory and on the localization homogenization technique associated with the self-consistent scheme. For representing the micro-damage on each slip system, an internal damage variable dS is introduced. The influence of the main parameters of this model (aggregate composition, damage interaction matrix Drs, and loading path) on the related plastic fatigue phenomena as the fatigue lives and the micro-damage heterogeneity is studied. Hence, various fatigue simulations are performed using several types of aggregates and different loading paths (simple and complex). It is shown that such parameters have great influences on the fatigue behavior. Moreover, the distributions of the local damage heterogeneity are studied under the effect of each determined parameter.