Results 121 to 130 of about 476 (147)
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Performance study of preliminary mini anechoic chamber fitted with coconut shell coated absorbers
2013 IEEE International Conference on Control System, Computing and Engineering, 2013An anechoic chamber is considered good when there is no signal reflection inside the chamber and also when there is no incoming signal from outside the chamber. The key element inside an anechoic chamber is the absorbing material. The evaluations of mini anechoic chamber fitted with coated absorbers were carried out by analyzing the absorption ...
Hasnain Abdullah Idris +11 more
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Tunable underwater sound absorption characteristics of 0–3 piezoelectric anechoic coating
The Journal of the Acoustical Society of AmericaPiezoelectric composite materials (PCMs) with shunt damping circuits are used widely in hydroacoustics because of the flexible adjustability of their parameters. PCMs offer good underwater sound absorption, but shortcomings remain, such as poor low-frequency sound absorption, narrow bandwidth, and a single dissipation mechanism.
Xinyu Jia +4 more
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A variable stiffness model for anechoic coating under hydrostatic pressure
A variable stiffness model (VSM) of the anechoic coating is proposed to calculate the sound absorption performance under hydrostatic pressure by considering both hyperelasticity and deformation. The expression for tangent stiffness is derived based on the Mooney-Rivlin dual parameter model. A VSM algorithm is then established.Jiahao Hu +3 more
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Journal of Sound and Vibration, 2018
Abstract Rubbery coatings embedded with air cavities are commonly used on underwater structures to reduce reflection of incoming sound waves. In this paper, the relationships between Poisson's and modulus loss factors of rubbery materials are theoretically derived, the different effects of the tiny Poisson's loss factor on characterizing the loss ...
Jie Zhong +4 more
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Abstract Rubbery coatings embedded with air cavities are commonly used on underwater structures to reduce reflection of incoming sound waves. In this paper, the relationships between Poisson's and modulus loss factors of rubbery materials are theoretically derived, the different effects of the tiny Poisson's loss factor on characterizing the loss ...
Jie Zhong +4 more
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Optimization Design of Acoustic Performance of Underwater Anechoic Coatings
Acoustics Australia, 2022Shuailong Zhou, Zhi Fang
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Applied Acoustics, 2019
Abstract The finite element method (FEM) is commonly used to analyze the underwater acoustic performances of rubbery coatings due to its flexibility to model scatterers of complex geometric dimensions. However, its calculation efficiency is always denounced as a drawback for its application on optimization design where a large number of repeated ...
Jie Zhong +4 more
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Abstract The finite element method (FEM) is commonly used to analyze the underwater acoustic performances of rubbery coatings due to its flexibility to model scatterers of complex geometric dimensions. However, its calculation efficiency is always denounced as a drawback for its application on optimization design where a large number of repeated ...
Jie Zhong +4 more
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Anechoic coatings obtained from two- and three-dimensional monopole resonance diffraction gratings
The Journal of the Acoustical Society of America, 2012Underwater sound reflections can be reduced in magnitude by a rubber coating including three-dimensional (3-D) cavities forming a doubly periodic diffraction grating. A monopole resonance for sphere-like cavities enhances absorption in the surrounding rubber solid.
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Note on the validity of using plane-wave type relations to characterize Alberich anechoic coatings
The Journal of the Acoustical Society of America, 1992The efficiency of echo reduction due to the coating of a rigid plane structure by a properly designed material can be determined via the measurement of the reflection and transmission coefficients of a panel made up with this material using a simple, plane-wave type relation.
Anne-Christine Hladky-Hennion +1 more
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The Journal of the Acoustical Society of America, 2014
Global optimization methods can be used to numerically determine optimal design parameters for an object. However, this does not by itself give a good appreciation of other parameter choices that may be almost as good and even preferable from other points of view.
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Global optimization methods can be used to numerically determine optimal design parameters for an object. However, this does not by itself give a good appreciation of other parameter choices that may be almost as good and even preferable from other points of view.
openaire +2 more sources