基于LMS与ANSYS Workbench的排气系统悬置参数的优化设计

Optimization Design of Suspension Parameters of Exhaust System Based on LMS and ANSYS Workbench

为了分析吊耳刚度对排气管振动的影响,提出了一种基于LMS Poly Max及ANSYS Workbench的优化设计方法。首先建立了排气管的三维实体模型以及有限元模型,并对其进行约束模态分析;其次,利用LMS软件对排气系统进行了试验模态分析,通过计算模态与实验模态进行对比,验证模型的正确性;最后,利用修正后的有限元模型,以排气系统的一阶固有频率为优化目标,运用ANSYS Design Explorer对其进行灵敏度分析以及优化设计。优化后发现排气管的一阶固有频率从23.73 Hz提高到34.9 Hz,从而避开了怠速时发动机的激励频率,为排气系统的减震、降噪提供了重要依据。

In order to analyze the impact of lug stiffness for exhaust pipe vibration, the optimal design method was mentioned based on the LMS PolyMax and ANSYS workbench. Firstly, the three- dimensional solid model and the finite element model of the exhaust pipe were established, and the constraint modal analysis was done. Secondly, the experimental modal analysis of the exhaust system was made by using the LMS software. By comparing calculated and experimental modal, it verifies the correctness of the model. Finally, the first natural frequency of the exhaust system was made as the optimization objectives by using the correeted finite element model and ANSYS Design Explorer to analysis its sensitivity and to make a design optimization. Lastly, the optimized first natural frequency of the exhaust pipe was inereased from 23.73 Hz to 34.9 Hz, thus avoiding the excitation frequency of the engine at idle. This study provides an important basis for damping and noise reduction of the exhaust system.