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

Abstract

Broadband sound absorption has consistently been a challenge in designing underwater sound absorption structure. Most research of underwater sound absorption structures 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 underwater sound absorption structure 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 2000-10000 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.

Research progress of noise reduction of composite structures of porous materials and acoustic metamaterials

“…[ [93][94][95] Space-coiling type Selective absorption of sound waves at specific frequencies can be achieved by adjusting the shape and size of the structure.…”

A review of hydroacoustic absorbing materials under hydrostatic pressure

“…共振吸 声机理主要是利用各种声学结构在特定频率处产生的 共振效应, 使得材料发生局部剪切变形, 形成纵波向横 波的转换以提高吸声 [20,70] . 除空腔和局域共振结构外, 螺旋通道 [71] 、薄膜型共振结构 [72] 、微穿孔板 [73~75] 和 Fabry-Pérot共振 [76,77] 等也被用于共振型吸声结构设计中.…”

A mechanically adjustable acoustic metamaterial for low- frequency sound absorption with load-bearing and fire resistance

“…For this case, the broadband noise control may not solve the problem of random noise with discrete peak spectrum, and it will also lead to redundancy in the spatial size of the broadband sound absorption material composed of multiple units. Membrane-based acoustic metamaterials have good low-frequency sound absorption properties [17,29], which may solve this problem. However, their poor load-bearing capacity and high temperature resistance greatly limit their applications.…”