Probabilistic reliability analysis of fatigue life based on Cosserat continuum theory
REN Yuan;YIN Jin;ZHANG Chengcheng;HOU Naixian;ZHANG Sheng;CHEN Biaosong;AVIC Commercial Aircraft Engine Co.,Ltd.;State Key Laboratory of Structural Analysis for Industrial Equipment,Dalian University of Technology;
Considering the strain gradient effect,an elastoplastic model of powder metallurgy superalloy is proposed on the basis of Cosserat continuum theory. The model takes into account the effect of microscale length and can eliminate the mesh dependence when solving the problem of localization of defects.Based on parametric variational principle,an efficient solution method is proposed. The original nonlinear problem is transformed into the complementary problem to solve by the method,which can greatly improve the efficiency and convergence of the solution. As to a hypothetical turbine disk model,the Cosserat scale parameter and the Basquin slope are considered as random variables,and Monte Carlo method and the second-moment method are used to calculate the probabilistic reliability of fatigue life.The results show that the efficiency of second-moment method is high in the case of ensuring accuracy.