A novel physical cycle-jump method for fatigue crack simulation of polycrystalline nickel-based superalloy

Abstract

In recent years, the crystal plastic damage model has been widely used in transgranular fracture. This paper designs mixed dissipative energy damage based on stress fatigue. In general, long-period simulations must use cycle-jump method, and the transient nature of crack propagation significantly reduces the efficiency of mathematical extrapolation strategies. According to the physical correlation between the variables in the crystal plastic model, an equivalent load block is established to replace the real-time load spectrum, and a novel physical cycle-jump strategy is realized. Under the stable and disturbed load spectrum, the accuracy and efficiency of the physical strategy are better than that of the mathematical strategies. The fatigue crack propagation in the three-dimensional polycrystalline model is in good agreement with the experimental results. Finally, by focusing on crack nucleation elements, the fatigue damage parameters are determined using genetic optimization. The error between the simulated fatigue life and the test is within 7%.