Simulation of fatigue crack growth by crack tip plastic blunting using cohesive zone elements

The propagation of a fatigue crack in 2D specimens by crack tip plastic blunting is simulated by using a Finite Element implementation of the strip-yield model. At each cycle, the crack growth is assumed to result from the variation of the Crack Tip Opening Displacement (Delta CTOD). The implementation is based on cohesive elements with an elastic perfectly plastic behavior, which allows to simulate, the crack closure phenomena due to the plastic wake behind the crack tip. A mesh sensitivity analysis provides the minimum number of elements requested in the crack tip plastic zone for a given accuracy. Then, the advance scheme based on crack tip blunting is described. Finally, the variation of the opening load with respect to the load ratio R, and to the maximum load is investigated and compared with analytical results. (C) 2010 Published by Elsevier Ltd.