车辆排气系统模态和振动特性及组件敏感性研究

A Study on Modal and Vibration Performance and Components Sensitivity of Vehicle Exhaust System

建立排气系统有限元模型并进行了验证。利用所采集的加速度信号作为边界条件,计算分析了排气系统吊钩的动态响应力。结果表明,在发动机激励作用时,吊钩载荷响应力和加速度在同一频率出现峰值,且处于弯管处的吊钩由于有附加扭矩而造成动态响应力较大。对吊耳刚度进行敏感性分析,发现排气系统对吊耳Z向刚度较敏感,因此可以通过优化吊耳Z向刚度来减小吊钩处动态响应力。

The finite element analysis（FEA） model for exhaust system has been established and verified in this paper.Using the collected acceleration signals as the boundary condition,the paper has calculated and analyzed the dynamic response force of the exhaust hook.The result shows that under engine excitation,the peak value of the hook load response force and that of the acceleration occur under the same frequency.Moreover,hook at the bent pipe bears relatively large dynamic response force due to the additional torque.Through sensitivity analysis of the hook stiffness,it is found that the exhaust system is more sensitive to hook stiffness in Z direction,therefore the hook dynamic response force can be reduced through optimizing the hook stiffness in Z direction.