Microscopic inhomogeneity coupled with macroscopic homogeneity: A localized zone of energy density for fatigue crack growth

A localized energy density zone (EDZ) model is presented to reflect the microscopic non-equilibrium and non-homogeneity (NENH) effects in a fatigue failure process. Micro and macro effects can thus be included in the S-N curves of LC4 aluminum alloy. The scatter of the fatigue test data is shown to be contributed by the material microscopic effects. A schematic for the EDZ model to simulate the fatigue crack growth from micro-scale to macro-scale by reflecting the NENH effects.