Abstract:  In order to realize the lightweight of a titanium alloy connecting rod of an agricultural internal combustion engine, the connecting rod model is established by SolidWorks and imported into the associated ANSYS Workbench. The finite element analysis of the connecting rod is conducted. The stress distribution and deformation of the connecting rod under four working conditions are obtained, and the static analysis is carried out. The analysis results show that the maximum equivalent stress under all working conditions is in the transition region of rod body and small head, and there are different degrees of stress concentration. Through the modal analysis of titanium alloy connecting rod, the first six natural frequencies and modal shapes are obtained. Based on the modal analysis, the harmonic response analysis is accomplished, and the displacement frequency response curves of connecting rod in X, Y and Z axes are obtained. Finally, the topology optimization design of titanium alloy connecting rod is carried out, so that the weight of connecting rod is reduced from 205.55g to 135.31g, which is reduced by 34.17%. The stress decreases from 324.08MPa to 303.31MPa, which is reduced by 6.41%. The redesigned titanium alloy connecting rod realizes the maximum utilization efficiency of materials, reduces the weight of titanium alloy connecting rod, and determines the feasibility of topology optimization.

Key words: titanium alloy connecting rod, static characteristic analysis, modal analysis, harmonic response analysis, topological optimization

摘要： 为实现某农用内燃机钛合金连杆的轻量化，利用SolidWorks建立连杆三维模型导入与之关联的ANSYS workbench中对连杆进行有限元分析，得到四种工况下连杆的应力分布和变形情况进行静力学分析。分析结果表明所有工况的最大等效应力均在杆身和小头过渡区域，存在不同程度应力集中现象。通过对钛合金连杆进行模态分析，获取前六阶固有频率和模态振型，以模态分析为基础进行谐响应分析得出连杆X、Y、Z轴方向位移—频率响应曲线。最后对钛合金连杆进行拓扑优化设计，使连杆重量从205.55g减少至135.31g，减少34.17%；应力从324.08MPa减少至303.31MPa，减少6.41%。重新设计的钛合金连杆实现了材料的最大利用效率，减少钛合金连杆重量，确定拓扑优化的可行性。

关键词: 钛合金连杆, 静力特性分析, 模态分析, 谐响应分析, 拓扑优化