Recent study progress of underwater sound absorption coating

Abstract

Based on the recent development of underwater sound absorption coatings, this paper analyzes the evolution of underwater sound absorption coatings from two aspects: traditional structures and metamaterials. The traditional structures are divided into three types: cavity structures, composite structures, and impedance‐matching structures. First, the development history of traditional structures, from cavities to hybrid structures, is presented, and the optimization and recent improvements in sound absorption fundamentals are explained. For different types of structures, the sound absorption effects of their respective structures are presented. At the same time, recent development progress of underwater coating metamaterials is summarized, and the sound absorption fundamentals and effects of local and nonlocal resonance types are compared. In addition, typical underwater sound absorption metamaterials are described in detail, and the application prospect of the acoustic bubble structure in practice is summarized. Moreover, this paper compares and discusses various structural types of underwater sound absorption coatings and points out the shortcomings of recent related research. Finally, it points out current open issues in the field and suggests future development directions of underwater sound absorption coatings, defining the possible development focus of underwater sound absorption coatings.

Underwater sound absorption characteristics of compliant acoustic coatings with adjustable stiffness

“…Underwater acoustic coatings refer to the acoustic protective layer usually attached to the target surface of underwater vehicles and exposed to the water domain, leading to a reduction of sound reflection and an enhancement of sound absorption, which is critical for acoustic stealth of underwater vehicles [1]. * Author to whom any correspondence should be addressed.…”

Underwater acoustic self-focusing and bending in conformal Mikaelian lens by pentamode metafluid

“…developed in recent decades, providing opportunities for acoustic control [1]. By combining these materials with techniques like transformation acoustics, researchers have achieved remarkable accomplishments, including underwater acoustic cloaking [2][3][4][5][6], vortex and Bessel beams [7][8][9], absorbing [10][11][12] and so on. These developments have significantly improved the efficiency of underwater acoustic control.…”