Acoustic analysis for a sound-absorbing structure with multi-layered porous material

By using the transmission equation of acoustic wave in a layered media,the recursive formula of absorption coefficient of a multi-layered structure was derived.Then,for a double-layer structure made of porous sound-absorbing material,the effect of acoustic parameters including thickness,porosity and pore radius of each layer on the absorption coefficient was analyzed with numerical simulation.Based on the recursive formula,parameter optimization of a multi-layered sound-absorbing structure was investigated.It was shown that the multi-layered sound-absorbing structure made of porous sound-absorbing material has good sound absorption capacity and can reach satisfactory sound absorption level in a wider frequency range.The results provided a theoretical support for product design.