Continuum damage mechanics based probabilistic fatigue life prediction for metallic material

Abstract

Based on continuum damage mechanics, a probabilistic method of predicting high-cycle fatigue life for metallic material is proposed. First, macro-meso two-scale stress–strain equations are established by combining Eshelby-Kroner localization law and classic elastic–plastic constitutive equation. Second, two parameters in Lemaitre's fatigue damage evolution model are randomized. Samples of randomized parameters are obtained by inverse-analysis and optimization and probabilistic properties is calculated analytically based on non-intrusive polynomial chaos. The probabilistic method of predicting high-cycle fatigue life is established by coupling the model with macro-meso two-scale equations. The proposed algorithm is coded with Fortran, which is non-intrusive post-program of Finite Element Analysis(FEA). Constant amplitude fatigue test of aluminum alloy 2024-T3 coupon is performed to identify probabilistic properties of model parameters. To validate applicability of proposed method in engineering, wing wallboard structure is analyzed by FEA. Fatigue life of hot spot is predicted by proposed method. The corresponding fatigue test of the component is performed, which verifies the effectiveness of proposed method to predict probabilistic life of metallic components.