Research of optimization for crack propagation method

At present, extensive works have been done to predict the shape evolution of fatigue crack based on conventional numerical analysis method. However, few efforts have been made in the majorization of propagation points and increment for the accuracy of simulation. In this paper, a new error calculation method is proposed to quantify the simulation results and experimental results. Based on this, the influence of distribution and quantity of propagation points on the simulation results of crack propagation has been studied and optimized. And a kind of equivalent stress intensity factor amplitude expression based on the assumption that the stress intensity factor changes exponentially with crack depth is derived to achieve the larger crack growth increment by using calculus method. The validity is verified by comparing simulation results with existing expressions of stress intensity factor.