A thin-film acoustic metamaterial absorber with tunable sound absorption characteristics

A thin-film absorber with tunable acoustic properties over a wideband is designed based on the acoustic metamaterial theory. The thin-film acoustic metamaterial absorber (TFAMA) consists of a frame made of piezoelectric material and several flexible films with attached mass blocks (mass-spring vibration system). Based on the vibration mechanism of the mass-spring vibration system, a cellular model of local resonance form is established, and the material properties of negative effective mass are discussed. Combined with the vibration modal analysis of the coupling of mass block, elastic film, and piezoelectric material, the acoustic characteristics of the TFAMA under alternating voltage excitation are studied by finite element and experimental methods. The simulation and experimental results show that the sound wave can be well absorbed when it is incident on TFAMA to cause the membrane-cavity coupling resonance. By applying an alternating voltage to the TFAMA to excite the mass-spring vibration system to generate local resonance, the absorption of sound waves can be further enhanced in a relatively wide band near the excitation frequency. In view of the convenience of voltage parameter adjustment, the sound absorption band can be flexibly tuned in a wide range, including low frequency.

Automated summary

Tunable acoustic properties of a wideband thin-film absorber based on acoustic metamaterial theory are achieved. The absorber is composed of a piezoelectric frame and flexible films with attached mass blocks. By establishing a cellular model of local resonance and exploring the properties of negative effective mass, the absorber's acoustic characteristics under alternating voltage excitation are studied using finite element and experimental methods. The results show that the absorber can effectively absorb sound waves through membrane-cavity coupling resonance, and the absorption can be further enhanced by exciting the mass-spring vibration system with an alternating voltage.