Crack Growth Model under Creep-Fatigue Interaction
In the present paper, a new creep-fatigue crack growth model of J-integral criterion is proposed. The model is built based on the dislocation-free zone (DFZ) theory and cohesive zone model. The process of crack growth is viewed as the intermittent quasi-cleavage fracture of the DFZ. The microscopic void caused by creep will grow and join the dominant crack under creep-fatigue interaction. In this process, material’s plastic deformation induces the change of the dislocation’s density. The redistribution of dislocation will change the value of J-integral within the cohesive zone. When the value of J-integral attains the critical value Jc, crack will grow by the original width of DFZ. Based on it, a simple relation is employed to evaluate crack growth rate under creep-fatigue interaction. The calculated crack growth rate curve exhibits three different regimes, which is in agreement with the general crack propagation pattern under creep-fatigue interaction. The model gives a reasonable explanation for crack growth under creep-fatigue interaction. The calculated value is close to the value obtained by experiment.
Chaohe Chen, Yong Huang and Guangfan Li
R. Zhang and H. L. Li, "Crack Growth Model under Creep-Fatigue Interaction", Advanced Materials Research, Vols. 243-249, pp. 241-244, 2011