Microperforated metasurface panel backed by aerogel-filled cavities for broadband low frequency sound absorption

Abstract

Aiming at limited absorption rate and bandwidth of the traditional sound absorption materials in low frequency range, we present an acoustic metasurface that can achieve broadband absorption in the frequency range of 822 Hz–1244 Hz with the maximum absorption coefficient of almost 100% and the absorption coefficient above 90%. The metasurface is comprised of four detuned cells that are constructed by embedding M13 virus aerogels with different thicknesses into the air cavity behind the microperforated panel. The gradual changes in the aerogel thickness produce a continuous change of the resonance absorption peak in the four detuned cells with the backing cavity depths unchanged. The relatively broadband sound absorption is the result of the coupling between the detuned cells, which is explained well by the acoustical siphon effect. This finding and proposed method offer a new design approach for acoustic metamaterial and have great potential for passive airborne noise mitigation applications.