Modeling of Crack Propagation in Ductile Materials Under Cyclic, Proportional and Non-Proportional Loading Conditions

Abstract

The paper addresses the numerical calculation of multi-axial fatigue crack propagation in ductile materials under proportional and non-proportional cyclic loading conditions. The analysis is based on a phase field fracture theory proposed in earlier work, which describes crack propagation on the basis of the evolution of plastic strain. A plane stress formulation of the theory is developed and used to analyze both length scale effects and comparison with experimental results. The considered loading histories comprise proportional and non-proportional cyclic tension/compression and shear loadings. Generally, the predicted responses are in good agreement with the experimental results for proportional loading histories. Qualitative differences seem to exist, however, in what concerns the number of predicted cracks for non-proportional cyclic loading conditions.