PROBABILISTIC MESOMECHANICAL FATIGUE-CRACK NUCLEATION MODEL

A probabilistic mesomechanical crack nucleation model is proposed to l ink the microstructural material heterogeneities to the statistical sc atter in the macrostructural response. The macrostructure is modeled a s an ensemble of microelements. Crack nucleate within the microelement s and grow from the microelements to final fracture. Variations of the microelement properties are defined using statistical parameters. A m icromechanical 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 experim ental observations from the literature.