Underwater sound absorption characteristics of metamaterials with steel plate backing

Abstract

Generally, the better sound absorption characteristics can be achieved in the low frequency band by embedding resonance units into the conventional anechoic coating. However, in this way, the frequency range of effective sound absorption is relatively narrow, which limits the application of anechoic coating in engineering. In this paper, in order to optimize this sound absorption characteristics, a new type of underwater sound absorption metamaterials with multi-resonator are proposed based on the coupled resonance mechanism. The underwater sound absorption characteristics of the proposed metamaterials with steel plate backing are investigated by finite element method (FEM). The effect of coupled resonance between the resonators on the sound absorption characteristics of metamaterials is investigated. In addition, the effect of the geometric structure of steel plate backing on the sound absorption characteristics is studied as well. Numerical results show that the proposed metamaterials have many advantages over the conventional anechoic coating in underwater sound absorption due to the coupled resonance effect. Moreover, the steel plate backing has a significant effect on the sound absorption characteristics of the proposed metamaterials, especially, in the low frequency range.