Investigation of the Underwater Absorption and Reflection Characteristics by Using a Double-Layer Composite Metamaterial

It is well-known that the acoustic stealth of an underwater vehicle composed of a non-watertight structure has been facing severe challenges. The origins of this effect are associated with the fact that the coupling between the water and the mechanical structure is not negligible because both sides...

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Main Authors: Yi Zhu, Xinyang Zhao, Zhiyuan Mei, Haitao Li, Dajiang Wu
Format: Article
Language:English
Published: MDPI AG 2022-12-01
Series:Materials
Subjects:
Online Access:https://www.mdpi.com/1996-1944/16/1/49
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author Yi Zhu
Xinyang Zhao
Zhiyuan Mei
Haitao Li
Dajiang Wu
author_facet Yi Zhu
Xinyang Zhao
Zhiyuan Mei
Haitao Li
Dajiang Wu
author_sort Yi Zhu
collection DOAJ
description It is well-known that the acoustic stealth of an underwater vehicle composed of a non-watertight structure has been facing severe challenges. The origins of this effect are associated with the fact that the coupling between the water and the mechanical structure is not negligible because both sides are in the water. Along these lines, the idea of forward absorption and backward reflection was proposed in this work to address this issue. More specifically, a composite underwater acoustic metamaterial (AM) was designed based on different layers, namely a sound absorption layer and a sound insulation layer from the outside to the inside. The sound absorption layer was made of a soft rubber matrix with embedded steel scatterers (ESs) to enrich the coupled resonance effects, while the sound insulation layer was composed of hard rubber with a built-in cavity to improve the impedance mismatching between the AM and the water. The impact of the number and thickness of the embedded ESs on the acoustic performance of the AM was also thoroughly investigated via a finite element method (FEM). A fast non-dominated genetic algorithm (NAGA-II) with elite strategy was used to optimize the position and the size of the ESs. The optimization results revealed the high absorption at the forward incidence and the high reflection at the backward incidence. Thus, our work provides a novel and effective approach for improving the acoustic stealth of underwater vehicles composed of non-watertight structures.
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spelling doaj.art-63109f33e06d43c7af4267837e4d21652023-11-16T15:46:22ZengMDPI AGMaterials1996-19442022-12-011614910.3390/ma16010049Investigation of the Underwater Absorption and Reflection Characteristics by Using a Double-Layer Composite MetamaterialYi Zhu0Xinyang Zhao1Zhiyuan Mei2Haitao Li3Dajiang Wu4College of Naval Architecture & Ocean Engineering, Naval University of Engineering, Wuhan 430000, ChinaCollege of Naval Architecture & Ocean Engineering, Naval University of Engineering, Wuhan 430000, ChinaCollege of Naval Architecture & Ocean Engineering, Naval University of Engineering, Wuhan 430000, ChinaCollege of Naval Architecture & Ocean Engineering, Naval University of Engineering, Wuhan 430000, ChinaCollege of Naval Architecture & Ocean Engineering, Naval University of Engineering, Wuhan 430000, ChinaIt is well-known that the acoustic stealth of an underwater vehicle composed of a non-watertight structure has been facing severe challenges. The origins of this effect are associated with the fact that the coupling between the water and the mechanical structure is not negligible because both sides are in the water. Along these lines, the idea of forward absorption and backward reflection was proposed in this work to address this issue. More specifically, a composite underwater acoustic metamaterial (AM) was designed based on different layers, namely a sound absorption layer and a sound insulation layer from the outside to the inside. The sound absorption layer was made of a soft rubber matrix with embedded steel scatterers (ESs) to enrich the coupled resonance effects, while the sound insulation layer was composed of hard rubber with a built-in cavity to improve the impedance mismatching between the AM and the water. The impact of the number and thickness of the embedded ESs on the acoustic performance of the AM was also thoroughly investigated via a finite element method (FEM). A fast non-dominated genetic algorithm (NAGA-II) with elite strategy was used to optimize the position and the size of the ESs. The optimization results revealed the high absorption at the forward incidence and the high reflection at the backward incidence. Thus, our work provides a novel and effective approach for improving the acoustic stealth of underwater vehicles composed of non-watertight structures.https://www.mdpi.com/1996-1944/16/1/49underwater metamaterialacoustic absorptionacoustic reflectionNAGA-II optimization
spellingShingle Yi Zhu
Xinyang Zhao
Zhiyuan Mei
Haitao Li
Dajiang Wu
Investigation of the Underwater Absorption and Reflection Characteristics by Using a Double-Layer Composite Metamaterial
Materials
underwater metamaterial
acoustic absorption
acoustic reflection
NAGA-II optimization
title Investigation of the Underwater Absorption and Reflection Characteristics by Using a Double-Layer Composite Metamaterial
title_full Investigation of the Underwater Absorption and Reflection Characteristics by Using a Double-Layer Composite Metamaterial
title_fullStr Investigation of the Underwater Absorption and Reflection Characteristics by Using a Double-Layer Composite Metamaterial
title_full_unstemmed Investigation of the Underwater Absorption and Reflection Characteristics by Using a Double-Layer Composite Metamaterial
title_short Investigation of the Underwater Absorption and Reflection Characteristics by Using a Double-Layer Composite Metamaterial
title_sort investigation of the underwater absorption and reflection characteristics by using a double layer composite metamaterial
topic underwater metamaterial
acoustic absorption
acoustic reflection
NAGA-II optimization
url https://www.mdpi.com/1996-1944/16/1/49
work_keys_str_mv AT yizhu investigationoftheunderwaterabsorptionandreflectioncharacteristicsbyusingadoublelayercompositemetamaterial
AT xinyangzhao investigationoftheunderwaterabsorptionandreflectioncharacteristicsbyusingadoublelayercompositemetamaterial
AT zhiyuanmei investigationoftheunderwaterabsorptionandreflectioncharacteristicsbyusingadoublelayercompositemetamaterial
AT haitaoli investigationoftheunderwaterabsorptionandreflectioncharacteristicsbyusingadoublelayercompositemetamaterial
AT dajiangwu investigationoftheunderwaterabsorptionandreflectioncharacteristicsbyusingadoublelayercompositemetamaterial