An effective method to enhance the underwater sound absorption performance by constructing a membrane-type acoustic metamaterial

Broadband sound absorption has consistently been a challenge in designing underwater sound absorption structure (USAS). Most research of USASs achieve broadband sound absorption through structural optimization, which curbs the freedom of designing, and commonly alights it at the expense of increased thickness. In this paper, a method is reported to broaden the frequency band of the USAS by embedding a membrane-type resonator into the cavity, which forming a membrane-type underwater acoustic absorption metamaterial. We demonstrate the mechanism of membrane-type metamaterial by theory, and verify it by simulation and experiment. The experimental results show that the sound absorption coefficient in the frequency range of 2000-10 000 Hz is significantly improved after implanting the membrane-type resonator into the cavity. The average sound absorption coefficient is increased by nearly 17%, and the improvement effect of the sound absorption covers to each frequency point, which is consistent with our expectation. As the case of applying membrane-type metamaterials to the design process of underwater acoustic structures, this research possesses great application potential in acoustic wave communication and device compatibility design technologies.