Design of multiple-resonant phononic metasurface for sound absorbing and energy harvesting devices

Abstract Acoustic metasurfaces, which utilize acoustically resonating structures, enable precise control and shielding of sound waves through compact, subwavelength devices. In this study, we propose a multi-resonant metasurface design comprising a decorated membrane, Helmholtz resonators, and a defective pillar array. The proposed structure facilitates both sound absorption and energy harvesting. The effectiveness of its multiple-resonance mechanism was validated through numerical and experimental analyses. Numerical calculations revealed three resonant peaks within the frequency range of 500 Hz to 4000 Hz, achieving an average absorption coefficient of over 90%. Additionally, the structure demonstrated an average generated voltage of 1.6 mV as the potential difference across the PZT patch. Furthermore, we propose the application of this structure in the development of phononic-structural metasurfaces. This metasurface comprises multiple resonant structures of varying sizes, enabling the superposition of resonance peaks from individual units. This design facilitates broadband sound absorption in the audible frequency range.