基于SFEM的结构元件疲劳可靠性分析

将结构元件的弹性模量、泊松比、几何尺寸定义为随机场,并将随机场离散成随机变量,将抗拉强度定义为随机变量,采用Monte Carlo随机有限元法(MCSFEM),给出了元件危险点应力的随机分布。由危险点应力分布、材料的p-S-N曲线和Miner理论给出了概率名义应力法,计算常幅载荷下元件的寿命分布,并利用剩余寿命模型计算元件的可靠度。给出了两个算例,结果表明:计算结果与试验结果吻合良好。

Fatigue Reliability Analysis on Structural Elements Based on SFEM

The Young's modulus,Poisson's ratio and geometry dimension of structural components are considered as stochastic fields and the fields are separated as stochastic variables.And the tensile strength of materials is considered as stochastic variables.The stress random distribution in fatigue failure zone is computed by the Monte Carlo stochastic finite element method(MCSFEM).A probabilistic nominal stress approach is proposed based on Miner's cumulative fatigue damage rule,the p-S-N curves of the material and the stress random distribution.The fatigue life distribution of structural elements on the constant amplitude loading is computed by the probabilistic nominal stress approach.Then the residual life model is used to estimate the reliability of structural elements.Two examples are given and the results show that the simulation data are in agreement with the experimental data.