摘要连杆作为发动机的主要传递动力的构件，承受着由活塞传递的周期性变化的气体 压力作用，工作环境极其恶劣，因而其结构非常容易损坏。随着发动机发展的方向转 变为大功率和高速度，故对连杆的要求变得更加严格。86008

本文首先采用传统的方法得出连杆的受力大小、方向与运动情况，并求解出了静 态研究所需要的边界条件。静态分析中，将在 Pro/Enegineer 中建的三维实体模型导 入 ANSYS Workbench 有限元软件中，得到连杆在最大拉压工况下的应力与变形情况， 为其优化分析打好了基础。在连杆的动态研究中，通过 Workbench 软件求解后获得了 其模态振型与频率，可以给发动机连杆的优化设计作为参考。

本文采用了结构优化的方法对连杆进行了优化设计。先根据要求将 Pro/E 中的模 型参数化，使用其调用 Workbench 软件后建立有限元模型的参数化。文中将连杆模型 的尺寸参数作为设计变量，连杆的最大应力和最大变形量作为约束条件，连杆的质量 作为目标函数进行优化分析。在连杆不发生损坏的前提下，使其质量减轻了 9。0%， 形状得到改善。

毕业论文关键词：发动机连杆；有限元分析；静强度分析；动态分析；优化分析；

Abstract Connecting rod as the main transmission mechanism of the engine, which are subjected to the periodic change of the gas pressure by the piston, and the working environment is extremely bad, so its structure is very easy to damage。 With the development of the engine to the direction of high power and high speed, the requirements of the connecting rod become more stringent。

In this paper, the traditional method is used to obtain the force size, direction and motion of the connecting rod, and the boundary conditions are solved。 In the static analysis, the 3D model which is built  in  Pro/Enegineer  is  introduced  into  the  ANSYS Workbench 。Then the stress and deformation of the connecting rod under the maximum tensile condition and the maximum compression condition were obtained, which are the basis for the optimization analysis of the connecting rod。 In the dynamic analysis of the connecting rod, the modal vibration mode and frequency of the connecting  rod  are obtained through the analysis of Workbench software, which provides a reference for the optimal design of the connecting rod。

In this paper, the structural optimization analysis method is used to optimize the connecting rod。 Firstly, the model which is built in Pro/E is parameterized, then the parameters of the finite element model are established by calling the Workbench software。 In this paper, the size parameters of the connecting rod model are taken as the design variables, the maximum stress and deformation of the connecting rod are taken as the constraint conditions, and the quality of the connecting rod as the objective function is optimized。 Under the condition that the connecting rod is not damaged, the quality of the connecting rod is reduced by 9%, and the shape of the connecting rod is optimized。

Key words: engine connecting rod; finite element analysis; static strength analysis; dynamic analysis; optimization analysis;

目 录

第一章 绪论 1

1。1  选题的目的和背景 1

1。2  国内外研究现状及发展 1

1。3  主要研究内容 3

第二章 连杆的运动与受力分析 4

2。1  连杆的运动分析 4

2。1。1  连杆的主要运动机理