A Vibro-Acoustic Coupling Analysis of Bus Passenger Compartment Based on the Finite Element Method

Based on the finite element method (FEM), this paper presented a technique for analyzing the vibro-acoustic coupling characteristics of bus passenger compartments. In view of sound quality of vehicle interior noises in the low frequency range, the acoustical, structural and coupled acoustic-structural FEM models of the passenger compartment of a sample bus are respectively established for modal, harmonic response analysis. The correlation of the resonance frequencies from 0Hz to 200Hz of the structural vibration, cavity acoustic modals and the coupled vibro-acoustic modals of the bus body is revealed. The harmonic response results suggest that the sound pressure levels at any observed point in the interior cavity have a similar curve pattern in frequencies, but different in their amplitudes. In the low frequency range, the main resonance frequency of the sample bus is 80Hz, which is mainly due to the cavity acoustic modals and the vibro-acoustic coupling relationship of the bus body system. The newly proposed technique can be extended to other types of vehicle for interior noise prediction and sound source recognition and further reduction.