Probabilistic mesomechanical fatigue crack nucleation model

A probabilistic mesomechanical crack nucleation model is proposed to link the microstructural material heterogeneities to the statistical scatter in the macrostructural response. The macrostructure is modeled as an ensemble of microelements. Crack nucleate within the microelements and grow from the microelements to final fracture. Variations of the microelement properties are defined using statistical parameters. A micromechanical slip band decohesion model along with a Paris law crack growth model are used with first order reliability methods and Monte Carlo simulation to determine the distribution of fatigue life for the macrostructure. The modeled response is compared to trends in experimental observations from the literature.