Fatigue Modelling with a Cyclic Cohesive Zone Approach

Various cohesive zone models have been applied to simulate fatigue crack growth. Here, an extended model is presented that allows the prediction of damage evolution under monotonic as well as cyclic loading conditions. The proposed damage evolution equation incorporates a local endurance limit which has been proven to enable the description of the relation of crack extension rate vs. cyclic load in all stages. This study addresses the predictive capabilities of the model with respect to fatigue life under homogeneous stress-based loading. The influences of the model parameters on life-time and endurance limit are investigated. Nu- merical simulations with variable load amplitude demonstrate non-linear damage accumulation characteristics which qualitatively match experimental observations.