商用型重卡后排气系统模态仿真方法及优化设计

Modal Simulation Method and Optimization Design for Rear Exhaust System of Commercial Heavy Truck

为提高重卡后排气系统模态仿真分析的精确性,对增压器涡壳、中间体和压气机3部分分别进行建模。基于有限元模型进行仿真,后排气系统热端一阶模态值为70.8Hz,与试验测试值71.9Hz吻合,二者相对偏差值为1.5%,验证了所建立的重卡后排气系统模态仿真方法是准确、可靠的。同时,基于系统热端模态提升原则改进管路布置方案,使得优化模态满足设计要求。结果显示,建立的模态仿真方法可准确获取系统模态及振型,识别共振危险点进行优化改进,减少了整车管路模态试验,缩短了设计周期,具有极大的实际应用价值。

In order to improve the accuracy of modal simulation analysis for exhaust system of heavy truck,the three parts of turbine shell,midbody and gas compressor of the turbocharger are modeled respectively.The simulation calculation is carried out based on the finite element model,the first order modal value of the rear exhaust system hot end is 70.8Hz,and it’s consistent with the test value of 71.9Hz,the relative deviation value is 1.5%,and it’s verify that the method is accurate and reliable.Meanwhile,based on the principle of hot end modal promotion,the pipeline layout is improved to make the optimized modal meet the design requirements.Through the established modal simulation method,the frequency value and vibration mode of the system can be obtained accurately,and the resonance danger point can be identified and optimized,and it has high practical application value to decrease the frequency of modal test, shorten the design cycle.