Abstract: Because the diesel engine connecting rod is subjected to complex forces during high-speed movement, the optimization of the connecting rod has been facing a single-objective, multiconstraint and multi-parameter optimization problem, which leads to complex calculations and is not easy to converge. Based on the finite element method and structural optimization theory, the simulation model of a diesel engine connecting rod is established in the paper, and the connecting rod is optimized by using the hierarchical optimization method and direct optimization method respectively. The results show that compared with the traditional direct optimization method, the hierarchical optimization method is better convergence of the objective function of each layer, 48% improvement of the computational efficiency, 11.74% weight reduction of the connecting rod after optimization, 13.6% decrease of the maximum stress, and 9% decrease of the maximum deformation. The study puts forward a new idea for the design and optimization of engine connecting rods, which can provide a useful reference for the optimization design of complex mechanical structures.

Key words: Diesel connecting rod; Hierarchical optimization; Finite element analysis; Parametric modeling

摘要： 由于柴油机连杆在高速运动过程中受力复杂，因此连杆优化一直面临着单目标、多约 束、多参数的优化问题，导致计算复杂、不易收敛。文中基于有限元法和结构优化理论，建 立了某柴油机连杆的仿真模型，分别采用分层优化方法和直接优化方法对该连杆进行了优化 设计。研究结果表明，相比于传统直接优化方法，分层优化方法每层目标函数收敛性较好， 计算效率提高 48%，优化后连杆减重 11.74%，最大应力下降 13.6%、最大变形降低 9%。研 究为发动机连杆设计及优化提出了新的思路，可为复杂机械结构优化设计提供借鉴。

关键词: 柴油机连杆；分层优化；有限元分析；参数化建模