Probabilistic fatigue life prediction of metallic components based on continuum damage mechanics

基于损伤力学的金属构件概率疲劳寿命预测方法

¹ School of Aeronautical Engineering, Zhengzhou University of Aeronautics, Zhengzhou 450046, China
² Research Institute of Unmanned Aerial Vehicles, Zhengzhou University of Aeronautics, Zhengzhou 450046, China
³ School of Aeronautics, Northwestern Polytechnical University, Xi'an 710072, China

Received: 22 June 2020

Abstract

Based on continuum damage mechanics, a probabilistic method of predicting high-cycle fatigue life for metallic components 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, some parameters in Lemaitre's fatigue damage evolution model are randomized. Probabilistic properties of which are obtained by inverse-analysis and optimization. Then, the probabilistic method of predicting high-cycle fatigue life is established by coupling the model with macro-meso two-scale equations. And the proposed algorithm is coded with Fortran language, which is non-intrusive post-program of FEM analysis. Next, constant amplitude fatigue test of Al 2024-T3 coupon is performed to determine probabilistic properties of model parameters. Finally, as the object of study, wallboard is analyzed by FEM. Taking skin-strip component as research object, the 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.

摘要

基于连续介质损伤力学，提出了一种预测金属构件高周疲劳寿命的概率方法。结合Eshelby-Kroner局域化准则和金属典型弹塑性本构方程构建了宏细观双尺度应力应变桥联方程；将Lemaitre疲劳损伤演化模型中部分参数随机化，通过对模型反演优化获取其概率特性。结合双尺度桥联方程和疲劳损伤演化概率模型建立了预测高周疲劳寿命的概率方法，通过Fortran编程实现新算法，作为有限元分析的非嵌入后处理程序。完成了铝合金2024-T3光滑圆棒常幅谱疲劳实验，从而确定模型参数概率特性，以某型飞机蒙皮-带板搭接壁板为研究对象，利用新方法预测其危险点概率疲劳寿命，并完成了相应疲劳实验，验证了新方法预测金属构件概率疲劳寿命的有效性。