Design and analysis of periodic acoustic metamaterial sound insulator using finite element method

In this article, a design of acoustic metamaterial containing Helmholtz resonators periodically embedded in a porous material is investigated for aerospace applications using the finite element method (FEM). The results obtained using the FEM are compared with the results of the theory, and the proposed transfer matrix method and good agreements are obtained. The transfer matrix method was combined with FEM calculations for two different termination conditions (plane wave radiation and rigid wall) in order to retrieve the equivalent matrix of the porous layer with the integrated periodic resonator. The equivalent matrix is then coupled analytically in series with others matrices. Finite element method studies are carried out on single and double wall configurations, and the effects of different resonator parameters and the air gap on the transmission loss are illustrated. The influences of the orientation of the neck opening and the resistivity of the porous material are also studied. Finite element method results for different incident angles are presented for single and double wall configurations. The proposed design can potentially be integrated into the panels of aircraft cabins in order to reduce the noise level at low frequencies inside the cabin.