基于拓扑与形状优化的柴油机机体低振动设计

为实现机体的低振动优化设计,在试验验证有限元模型正确性的基础上,采用拓扑优化和形状优化方法,保证不同层次优化模型的承接性,以机体模态频率和整机振动烈度值作为优化设计目标,采用数值模拟方法对机体进行振动响应分析,为机体的优化设计识别出机体振动状况分布。以四缸柴油机机体的虚拟样机为设计对象,通过拓扑优化与形状优化得到设计变量最优解,并综合考虑相关因素确定全部布局和细节设计的最终优化方案。优化结构分析结果表明,优化后各阶模态频率均得到了提高,同时整机振动烈度值降低了34.8%,优化后的机体在满足结构刚度和强度条件下实现了机体振动烈度处于安全区域。研究表明所提出的拓扑优化和形状优化在设计效率和精度都有所提高,在机体的低振动设计中可行且有效。

Block Design of Diesel Engine for Low Vibration Level Based on Topology and Shape Optimization

In order to achieve a low vibration design of engine block,verify the correctness of finite element model based on the test method,ensure the undertake of different levels of optimization model using the method of topology and shape optimization,modal frequency and vibration intensity of engine block are taken as optimization objectives,vibration analysis of engine block is made in the simulation,and the body vibration condition distribution are identified in the optimization design.The four cylinder engine block is set as the design objective,the optimal solution design variables are got through the topology optimization and shape optimization method,and then the final optimization scheme with whole layout and detailed design are obtained.The results of optimized structure show that frequencies of each mode are improved,and the vibration intensity value of engine block decreases by 34.8%,then vibration intensity of improved engine block is minimized in a safe area subject to rigidity and strength constraints.Efficiency and precision of the combination method of topology and shape optimization has an obvious enhance,and the feasibility and efficiency of the proposed methods are demonstrated by the experiment.