Effect of plate vibration on sound absorption of the micro-perforated elastic plate

Abstract

Perforated plates have long been used as sound absorbers, and many studies have been done on their acoustic characteristics. In these studies, the effect of plate vibration caused by the incident sound wave is neglected. This is reasonable for the perforated plate of ordinal design [D. Takahashi, Appl. Acoust. 51 (1997)]. However, if the ratio of perforation decreases, e.g., in case of the micro-perforated plate, the effect of plate vibration is considered to be distinct, because the flow resistance of the plate is relatively large in this case. In this study, a new theoretical model for predicting the acoustic characteristics of the micro-perforated elastic plate (MPEP) is presented. This model includes the effect of plate vibration caused by the pressure difference between both surfaces of the plate. Numerical experiments are also carried out with this model. From the results, it may be said that the plate vibration occurs when the surface porosity of the perforated plate is roughly under 1%. This model can be applied to the perforated plates of any flow resistance, i.e., from the ordinarily perforated plate to nonperforated plate throughout.