A Short Crack Growth Model for the Prediction of Fatigue Lives under Multiaxial Nonproportional Loading
Initiation and short fatigue crack growth have been investigated under nonproportional cyclic loading. A critical plane approach based on fracture mechanics is used for modelling the fatigue process. A Paris-type crack growth law, formulated using the effective cyclic J-integral as crack driving force parameter, is integrated to give crack growth curves. Crack opening stresses and strains are calculated with approximation equations. Jiang`s plasticity model is used to predict the stress-strain path. The good agreement beween model and real damage evolution is shown comparing experimentally determined crack growth curves, crack orientations, and life curves.