Simulation of fatigue crack growth with a cyclic cohesive zone model.

Fatigue crack growth is simulated for an elastic solid with a cyclic cohesive zone model (CZM). Material degradation and thus separation follows from the current damage state, which represents the amount of maximum transferable traction across the cohesive zone. The traction-separation relation proposed in the cyclic CZM includes non-linear paths for both un- and reloading. This allows a smooth transition from reversible to damaged state. The exponential traction-separation envelope is controlled by two shape parameters. Moreover, a lower bound for damage evolution is introduced by a local damage dependent endurance limit, which enters the damage evolution equation. The cyclic CZM is applied to mode I fatigue crack growth under $$K_{\mathrm{I}}$$ -controlled external loading conditions. The influences of the model parameters with respect to static failure load $$K_{\mathrm{0}}$$ , threshold load $$\varDelta K_{\mathrm{th}}$$ and Paris parameters $$m, C$$ are investigated. The study reveals that the proposed endurance limit formulation is well suited to control the ratio $$\varDelta K_{\mathrm{th}}/K_{\mathrm{0}}$$ independent of $$m$$ and $$C$$ . An identification procedure is suggested to identify the cohesive parameters with the help of Wöhler diagrams and fatigue crack growth rate curves. [ABSTRACT FROM AUTHOR]