Sound Absorption Characteristics Research On Multi-layer Microperforated Panel Connected By Springs

The micro-perforated panel structure has good sound absorption ability at middle-low frequency, and it is a kind of clean and pollution-free environmentally friendly materials. Therefore, sound absorption structure of micro-perforated panel (MPP) becomes the focus of scholars in the modern society suffered by noise pollution. In order to make MPP obtain a better sound absorption performance at low-frequency, this article is based on Dah-You Maa’s basic theory of MPP, analyzes sound-absorbing performance of general MPP and MPP connected by springs with the analytical method based on acoustic theory and the acoustoelectric analogy method.Firstly, the article is based on the acoustic absorption theory of micro-perforated panel and electrical equivalent circuit principle, builds equivalent circuit diagram of MPP with single, double, or three layers, and calculates acoustic impedance. The sound absorption coefficient is calculated by MATLAB. The absorption coefficient of MPP with single, double, or three layers is compared. And, the effect of cavity depth, plate thickness, hole-diameter, and perforation rate of MPP with three layers is analyzed.Secondly, acoustic impedance of MPP connected by springs with three-layer and five-layer is calculated by using coustoelectric analogy method. Then, we compare the sound absorption performance of the traditional multilayer MPP and multilayer MPP connected by springs. The results show that the sound absorption performance of MPP connected by springs is superior to the traditional structure at middle-low frequency. Then emphatically analyze effect of structural parameters on the sound absorption performance of MPP connected by springs with three-layer.Lastly, we analyze the sound absorption performance of MPP connected by springs with three-layer using the analytical method based on acoustic theory and obtain the sound absorption coefficient more accurately. Through the comparison with absorption coefficient curve obtained by analytical method based on acoustic theory and the acoustoelectric analogy method, we find that the acoustic absorption band at middle-low frequency gotten by the two methods is roughly same. However, the absorption coefficient of two curves is not the same. It illustrates acoustoelectric analogy method exists errors.