轿车声固耦合低频噪声的有限元分析

Finite Element Analysis on the Car Interior Low-frequency Noise with Acoustic-structural Coupling

建立结构载荷激励下乘坐室空腔声学系统和声固耦合系统的有限元模型。利用有限元软件ANSYS和LMS V irtual.lab对某轿车乘坐室结构与空腔声模态的频率和振型进行分析,采用直接法和模态叠加法对该轿车车内噪声仿真结果进行比较,指出采用模态叠加法计算声固耦合问题时,对于结构模态阶数的提取要求。通过计算仿真分析该模型低频噪声在频域中的分布情况,为降低由结构振动引起的车内低频噪声提供结构修改和声学修改依据。

A finite element model for the structure, cavity acoustics and acoustic-structure coupling system of the passenger compartment in a car is established. By making use of FEA software ANSYS and LMS virtual, lab, a modal analysis is performed and the structural vibration modes and cavity acoustic modes of the compartment are obtained. In-car noise simulation is conducted with both the direct and modal superposition methods, and it is found that using modal superposition method can get almost identical results in around 10 times less time, provided that sufficient number of modes are included. Finally the distribution of interior low-frequency noise in frequency domain is studied. These provide a basis for structural and acoustic modifications to reduce the interior low-frequency noise of passenger cars.