Abstract: The crack closure in the process of dynamic crack propagation is modeling by the finite element method and Jiang-Sehitoglu cyclic plastic constitutive model. The crack closure loading and opening loading are obtained by the FE results with different loading conditions. The influence of different maximum loadings and crack lengths will be analyzed. The relationship between crack propagation behavior and crack closure will be studied based on the FE results. The crack closure is considered as the main mechanism on crack propagation behavior. An improved model to calculate the effective stress intensity factor range will be proposed and the effective stress intensity factor range is considered as the driving force of crack propagation. The prediction formulation of crack growth rate is fitted about the 16MnR steel. The predicted results will be compared with the results of the crack growth experiments and the predicted results are very close to the obtained results in experiments.

Key words: Crack closure, Crack growth rate prediction, Effective stress intensity factor range, Overload mechanism