On the accuracy and optimization application of an axisymmetric simplified model for underwater sound absorption of anechoic coatings

2019 ◽  
Vol 145 ◽  
pp. 104-111 ◽  
Author(s):  
Jie Zhong ◽  
Honggang Zhao ◽  
Haibin Yang ◽  
Jianfei Yin ◽  
Jihong Wen
2021 ◽  
Vol 7 ◽  
Author(s):  
Junyi Wang ◽  
Jiaming Hu ◽  
Yun Chen

Underwater acoustic wave absorption and control play an important role in underwater applications. Various types of underwater acoustic metamaterials have been proposed in recent years with the vigorous development of acoustic metamaterials. Compared with airborne sound, underwater sound waves have a longer wavelength and much smaller propagation loss, making them more difficult to control. In addition, given that the acoustic impedance of water is much greater than that of air, numerous conventional materials and structures are not suited to underwater use. In this paper, we propose a composite structure based on an excellent broadband low-frequency sound absorber of air using aluminum mixed with rubber. Our composite structure possesses broadband low-frequency (<1,000 Hz) sound absorption underwater, omnidirectional high sound absorption coefficient under the oblique incidence (0–75°), and pressure resistance. It has promising applications for underwater acoustic wave control and contributes to the design of underwater acoustic metamaterials.


2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Mohammad Lutful Hakim ◽  
Touhidul Alam ◽  
Mohamed S. Soliman ◽  
Norsuzlin Mohd Sahar ◽  
Mohd Hafiz Baharuddin ◽  
...  

AbstractMetamaterial absorber (MMA) is now attracting significant interest due to its attractive applications, such as thermal detection, sound absorption, detection for explosive, military radar, wavelength detector, underwater sound absorption, and various sensor applications that are the vital part of the internet of things. This article proposes a modified square split ring resonator MMA for Ku-band sensing application, where the metamaterial structure is designed on FR-4 substrate material with a dielectric constant of 4.3 and loss tangent of 0.025. Perfect absorption is realized at 14.62 GHz and 16.30 GHz frequency bands, where peak absorption is about 99.99% for both frequency bands. The proposed structure shows 70% of the average absorption bandwidth of 420 MHz (14.42–14.84 GHz) and 480 MHz (16.06–16.54 GHz). The metamaterial property of the proposed structure is investigated for transverse electromagnetic mode (TEM) and achieved negative permittivity, permeability, and refractive index property for each absorption frequency band at 0°, 45°, and 90° polarization angles. Interference theory is also investigated to verify the absorption properties. Moreover, the permittivity sensor application is investigated to verify the sensor performance of the proposed structure. Finally, a comparison with recent works is performed, which shows that the proposed MMA can be a good candidate for Ku-band perfect absorber and sensing applications.


2018 ◽  
Vol 143 (3) ◽  
pp. 1534-1547 ◽  
Author(s):  
Hunki Lee ◽  
Myungki Jung ◽  
Minsoo Kim ◽  
Ryung Shin ◽  
Shinill Kang ◽  
...  

1961 ◽  
Vol 33 (11) ◽  
pp. 1680-1680
Author(s):  
R. A. Rubega ◽  
A. Culver

2019 ◽  
Vol 12 ◽  
pp. 132-142 ◽  
Author(s):  
Kangkang Shi ◽  
Guoyong Jin ◽  
Ruijie Liu ◽  
Tiangui Ye ◽  
Yaqiang Xue

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