Design of non-circular membranes metasurfaces for broadband sound absorption

Acoustic metasurfaces have been attracting much attention due to their effectiveness in controlling sound wave propagation despite a structure well below the wavelength at operating frequency. We propose a novel decorated membrane resonator structure with multiple circular membranes leading to multiplexing the resonant modes through breaking symmetry of the membrane's vibrational modes. By numerical analysis, the structure is optimized for wideband (500 to 1500 Hz) sound absorption. The designed structure is fabricated by using a 3D printer and its sound absorption property is verified experimentally by an impedance tube measurement. The results demonstrate that the present approach is simple but effective to broadband sound absorption with thin and lightweight artificial acoustic structures.

This fulltext is available in Apr. 2021.