Sound Transmission Through Metamaterial-Based Double-Panel Structures With Poroelastic Cores

The sound insulation improvements using the metamaterial concept for double-panel structures with poroelastic cores are investigated in this paper. The metamaterial-based double-panel structures are constructed by replacing the bare panel with the metamaterial plate which consists of multiple local attachments attached to an infinite thin plate. Two numerical cases are classified according to the spacing between the adjacent attachment in the calculation of sound transmission of the proposed structure. The porous material is investigated by the Biot's model and the equivalent fluid model respectively for the two cases, where the sound transmission of the overall system is achieved by different analytical approaches-the effective medium method and the plane wave expansion method. Numerical results show that the metamaterial-based double-panel structures can exhibit more superior sound insulation performance than the normal double-panel structures over certain frequency ranges. In addition, the arising dip of the sound transmission loss due to the coincidence phenomenon can also be improved by using multiple detuned local attachments in the metamaterial plate. Further, the proposed structure provides more design space for tuning sound insulation performance of double-panel structures.