Prediction of the acoustic effect of an interior trim porous material inside a rigid-walled car air cavity model

Abstract

In this paper, a simplified car air cavity model for predicting the influence of an interior trim material on the cabin interior sound pressure level (SPL) was presented. This work studies a rigid-walled car cabin model with one flexible wall. The interior trim material (a porous sound-absorbing material) was mounted in between the enclosed car air cavity and the flexible wall. A single point acoustic source is used to acoustically excite the rigid-walled car air cavity model, where the loudspeaker is positioned at front corner of the car cabin to simulate noise entering via an airborne path. The variation of the car air cavity interior sound pressure level corresponding to the presence of different porous sound-absorbing materials was experimentally investigated for high frequencies. The acoustical effects of the interior trim porous material on the proposed structural and acoustic coupled system were predicted by using the Statistical Energy Analysis (SEA) method for noise in one third octave bands. The comparison of results revealed that the experimentally acquired car cabin interior sound pressure level agrees fairly well with the simplified SEA model, both with and without the porous sound-absorbing materials, for high frequency one third octave band levels.