Theoretical Investigation of Sound Insulation of Asymmetric Coupled-Membrane Acoustic Metamaterials

Being as simple and lightweight structure in controlling low frequency noise, membrane-type acoustic metamaterial has been paid more attention. In this paper, theoretical model and analytical approach are presented to study the low frequency transmission loss performances of coupled-membrane type acoustic metamaterial(CMAM). The influences of the symmetric and asymmetric structures on the noise attenuation characteristics are discussed. The results demonstrate that asymmetric structure of CMAM is an ideal sound insulation material. By choosing proper material properties, multi-frequency and broad band sound insulation can be get in low frequency range (<1000Hz).