Abstract: In order to increase the strength of bolt connected flange for thin-walled casing and reduce thestructural vibration and weight，and satisfy the higher performance of advanced aero-engines，the optimization design was studied for the structural parameters of casing model. The height and thickness of the flange，casing thickness and bolt numbers were selected as parameters variables. The structural mass，first natural frequency and maximum equivalent stress were determined as objective functions. The second-order response surface model was established according to the sample points by Box-Behnken method and the finite element calculation results.The weight coefficients were obtained by Analytic Hierarchy Process，and the genetic algorithm was adopted to conduct the multi-objective optimization of the casing. Finally，the modal tests and the finite element verification were performed on the optimized structure. The research indicates that the error between the modal test results and the finite element calculation is less than 6%. Meanwhile，the optimization has greatly increased the first natural frequency and reduced the structural mass and maximum equivalent stress by 5.28% and 13.64% respectively，which verifies the effectiveness and the feasibility of the optimization method proposed in this paper.

Key words: Thin-walled casing；Vibration strength analysis；Response surface model；Multi-objective

摘要： 为增大薄壁机匣安装边螺栓连接结构强度、减小其振动和重量，以满足现代航空发动机更高性能的要求，对机匣结构参数进行了优化设计。选取安装边高度、安装边厚度、机匣厚度和螺栓个数为参数变量，结构质量、一阶固有频率和最大等效应力为目标函数，根据Box-Behnken方法设计的样本点和有限元计算结果建立二阶响应面模型，基于层次分析获取权系数，并利用遗传算法对机匣结构进行多目标优化设计。最后，针对优化后的结构进行模态试验和有限元验证。研究表明，模态试验结果与有限元计算误差小于6%，同时优化显著提高了一阶固有频率，使其结构质量和最大等效应力分别降低5.28%和13.64%，验证了本文提出的优化方法的有效性和可行性。

关键词: 薄壁机匣；振动强度分析；响应面模型；多目标优化