基于可靠性的动车组电机吊架多目标优化设计

Multi-Objective Optimization Design of Motor Hanger for EMU based on Reliability

为有效实现结构轻量化设计,同时考虑结构参数、材料属性的不确定性对结构性能的影响,以动车组电机吊架为研究对象,提出一种结合响应面法与均值一次二阶矩法的多目标可靠性优化设计方法.首先建立电机吊架有限元模型,通过灵敏度分析确定优化变量.其次,采用最优拉丁超立方抽样方法进行仿真试验设计并分别拟合应力与质量的多项式响应面函数.再次基于应力-强度干涉理论构造极限状态函数,采用均值一次二阶矩法对极限状态函数进行均值估计与方差估计,进而获得可靠性指标函数.最后,建立以质量与应力标准差为目标、可靠性指标与应力均值为约束的数学模型,并采用NSGA-Ⅱ求解.研究结果表明:电机吊架在实现轻量化目标、提高结构稳健性的同时,强度满足可靠性要求.

In order to realize lightweight structural design effectively with considering the influence of structural parameters and material property uncertainty on structural performance, a multi-objective reliability optimization design method combining response surface method and mean value first-order second-moment method is proposed for the motor hanger of the emu. The finite element model of motor hanger is established, and the optimization variable is determined by sensitivity analysis. The optimal Latin hypercube sampling method is used to design the simulation experiment and fit the polynomial response surface function of stress and mass respectively. The limit state function is constructed based on the stress-strength interference theory, and the mean value estimation and variance estimation of the limit state function are carried out by the mean value first-order second-moment method to obtain the reliability index function. Finally, a mathematical model with mass and stress standard deviation as the target and reliability index and stress mean value as the constraint is established to find the solution with the NSGA-Ⅱ. The results show that the motor hanger achieves the goal of light weight and improves the robustness of the structure, while its strength meets the requirements of reliability.