基于模态灵敏度分析的客车车身优化

Structural optimization of a light bus body-in-white based on modal sensitivity analysis

针对提高国产某轻型客车的乘坐舒适性,解决车内振动和噪声剧烈问题,基于有限元仿真和道路试验的阶次跟踪方法进行振动和噪声原因分析,其原因为轮胎激励引起的车身结构共振。为避免共振,以白车身钣金件和骨架厚度为设计变量,以提高白车身前两阶固有频率为目的,用模态灵敏度理论对白车身进行优化设计和灵敏度分析;结合各钣金件和骨架的模态灵敏度和质量灵敏度,设计最优的改进方案并进行试验分析。试验结果验证了该优化方案的有效性与合理性。

In order to reduce abnormal vibration and noise of a domestic light bus, its finite element simulation and order tracking analysis of road test were performed to identify vibration sources, it was found that the rotation angular frequencies of the wheels and the first two natural frequencies of the body structure are overlapped, resonances occur, they lead to increased vibrations. To stagger the first two natural frequencies of the body and excitation frequencies, the thicknesses of sheet metal and skeleton of the body-in-white were chosen as the design variables, to raise the first two natural frequencies of the body-in-white was taken as the optimization objective, the optimization design and sensitivity analysis of the body-in-white was conducted. According to the modal sensitivity and mass sensitivity of sheet metal and skeleton, the optimal scheme was designed and test analysis was performed. Comparing the test results before and after optimization, the effectiveness and rationality of the optimization were verified.