Study on sound insulation performance of double-layer perforated panel under normal incidence waves

Abstract

Based on the single-hole model, the sound insulation performance of four perforated panel structures were studied, including single-layer perforated panel, double-layer perforated panel, double-layer through-hole panel and double-layer resonant panel. Based on the plane wave theory, a modified transfer matrix method (MTM) was developed to improve the accuracy of traditional transfer matrix method (TM). For MTM, acoustic length corrections were used to modify the transfer matrix to consider the influence of multi-dimensional waves. Then MTM was used to predict the transmission loss (TL) of the four perforated panel structures, and the results were compared with those of the finite element method (FEM). The comparison showed good agreement in the effective frequency range. Using the MTM, the effects of dimensions on the TL of the four perforated panel structures were studied. The double-layer perforated panel can significantly increase the TL at the medium and high frequencies, and the double-layer resonant panel structure can increase the TL at the low frequency because of the resonance. In addition, the TL amplitude is influenced by the opening ratio, which decreases rapidly with the increasing of opening ratio. The thickness of the panel and the spacing between the two layers can mainly change the width of the high absorption region. The parameters of the resonant neck can change the resonant frequencies and pass-by frequencies. Finally, the predictions of MTM are verified with the experimental results of double-layer perforated panel sample. The method in this paper can be used to design the perforated panel structure for sound insulation.