Tunable underwater sound absorption characteristics of 0-3 piezoelectric anechoic coating.

Piezoelectric composite materials (PCMs) with shunt damping circuits are used widely in hydroacoustics because of the flexible adjustability of their parameters. PCMs offer good underwater sound absorption, but shortcomings remain, such as poor low-frequency sound absorption, narrow bandwidth, and a single dissipation mechanism. In this paper, the tunable underwater sound absorption of a 0-3 PCM combined with a cavity structure and shunt circuit (PCMC) is studied systematically. First, the equivalent material parameters of 0-3 PCM are derived based on the Yamada model, and then a theoretical electroacoustic model is established for solving the absorption coefficient and is mutually verified with the numerical simulation method. On this basis, the tunable absorption characteristics of the structure are analyzed. The results show that coupling the energy dissipation mechanism of 0-3 PCM with the acoustic mechanism of the cavity structure not only achieves strong absorption at lower frequencies but also enriches the absorption mode in the mid-high frequencies by connecting the shunt circuits. Moreover, the influence of piezoelectric control variables and acoustic cavity morphology characteristics on structural sound absorption performance is further explored. Finally, the acoustic performance of PCMC is improved further via shape optimization and parameter optimization.