Effect of Poisson's loss factor of rubbery material on underwater sound absorption of anechoic coatings

Zhong, Jie; Zhao, Honggang; Hai-bin, Yang; Yin, Jianfei; Wen, Jihong

doi:10.1016/j.jsv.2018.02.022

Cited by 45 publications

(26 citation statements)

References 46 publications

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“…If one rewrites into the form , then M e and denotes the effective longitudinal dynamic modulus and loss factor, respectively. Considering the rubber material with an isotropic loss factor, i.e., η K = η μ = η 52,53 , one can easily get the real-number relations, using equations (12)~(14), as…”

Section: Resultsmentioning

confidence: 99%

“…Then, a simple one-dimensional transfer matrix approach is used to calculate the acoustic performances under normal incidence. The transfer matrix of the (n−1)th layer, T n −1 , relates the output pressure and velocity to the input pressure and velocity by 50,53,65 where , l n −1 and are respectively the wave number, thickness and impedance of (n−1)th layer, with ρ n −1 and being the density and longitudinal wave speed of this layer. The full transfer matrix T for the multi-layer structure is obtained as the product of the individual transfer matrix for the layers.…”

Section: Methodsmentioning

confidence: 99%

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Theoretical requirements and inverse design for broadband perfect absorption of low-frequency waterborne sound by ultrathin metasurface

Zhong

Zhao

Yang

et al. 2019

Sci Rep

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Effective absorption of low-frequency waterborne sound with subwavelength absorbers has always been a challenging work. In this paper, we derive two theoretical requirements for broadband perfect absorption of low-frequency waterborne sound by ultrathin acoustic metasurface under a finite-thickness steel plate followed by semi-infinite air. Based on the theoretical requirements, an acoustic metasurface, a rubber layer embedded periodically with cavities, is inversely designed to achieve perfect absorption at 500 Hz. The metasurface is as thin as 1% of the working wavelength and maintains a substantially high absorptance over a relatively broad bandwidth. The perfect absorption peak is attributed to the overall resonance mode of the metasurface/steel plate system. Besides, high absorption can still be achieved even if the loss factor of the given rubber material cannot meet the ideal requirement. Finally, a strategy to utilize the inherent frequency-dependent characteristics of dynamic parameters of rubber material is suggested to achieve an ultra-broadband perfect absorption. When the frequency-dependent characteristics of the given rubber matrix cannot meet the theoretical requirements, a broadband super-absorption can still be realized by properly designing the frequency position of perfect absorption of the cavity-based metasurface.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Theoretical requirements and inverse design for broadband perfect absorption of low-frequency waterborne sound by ultrathin metasurface

Zhong

Zhao

Yang

et al. 2019

Sci Rep

Self Cite

View full text Add to dashboard Cite

show abstract

“…In order to verify the accuracy of the calculation results of the finite element model, a 50 mm thick homogeneous coating was selected from Ref. [13] for calculation. e geometric parameters and material parameters of the coating are consistent with the literature.…”

Section: Finite Element Modelmentioning

confidence: 99%

“…Since viscoelastic materials are approximately incompressible materials, Poisson's ratio is difficult to be measured with high precision (the measurement accuracy is generally 0.01). According to this actual situation, researchers usually assume Poisson's ratio to be a value close to but less than 0.5 such as 0.49 [9,[13][14][15][16][17][18][19][20], 0.493 [21], 0.495 [15,19], 0.4997 [19], 0.49976 [15], and 0.499981 [22]. It can be seen that Poisson's ratio of viscoelastic materials is set differently in the above literatures (although the difference in value is very small).…”

Section: Introductionmentioning

confidence: 99%

“…In addition, in these literatures, Poisson's ratio is set as a static value that does not change with the frequency. In literature [13], when studying the influence of Poisson's loss factor on acoustic covering layer, the real part of Poisson's ratio is still regarded as a fixed value. In fact, Poisson's ratio of viscoelastic materials varies with frequency.…”

Section: Introductionmentioning

confidence: 99%

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Analysis of Sound Absorption Performance of Underwater Acoustic Coating considering Different Poisson’s Ratio Values

Luo

Yan³

et al. 2021

Shock and Vibration

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Viscoelastic material acoustic coating plays an important role in noise and vibration control of underwater equipment. The dynamic mechanical properties of the viscoelastic material have a direct effect on the sound absorption performance of the acoustic coating. The influence of Poisson’s ratio on sound absorption performance is studied. A finite element model was established to calculate the sound absorption performance of three typical acoustic coatings: homogeneous acoustic coatings, Alberich acoustic coatings, and trumpet cavity acoustic coatings, and the influence of Poisson’s ratio on the sound absorption performance of the three kinds of acoustic coatings was analyzed. The results show that when Poisson’s ratio varies from 0.49 to 0.4999, the larger Poisson’s ratio is, the larger the frequency of the first absorption peak is, the smaller the absorption coefficient below the frequency of the first absorption peak is, and the smaller the average absorption coefficient in the whole analysis frequency range is. The dynamic Poisson’s ratio with the change of frequency is obtained by interpolating the test results and static Poisson’s ratio finite element calculation results. The calculation results show that the dynamic Poisson’s ratio can get more accurate calculation results. This work can provide a reference for researchers to set Poisson’s ratio in theoretical analysis and finite element analysis of acoustic coating.

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Underwater Scattering Exceptional Point by Metasurface with Fluid‐Solid Interaction

Zhou,

Jiang,

Zhu

et al. 2024

Adv Funct Materials

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Exceptional point (EP), a special degeneracy in non‐Hermitian systems, has exhibited various distinctive wave characteristics. However, the conventional synthesis of scattering EPs in acoustics is confined to rather limited methods for breaking Hermiticity, typically requiring intrinsic losses or open interfaces. Here, the concept of synthesizing scattering EPs is theoretically and experimentally demonstrated by leveraging a metasurface with fluid‐solid interaction (FSI) in water. The incorporation of FSI offers a novel mechanism to customize natural radiation losses. Simulations and experiments consistently confirm that synthesized EPs result in extremely asymmetric scattering patterns, even in the case of spatially impenetrable metasurfaces. This enhanced spatial symmetry breaking benefits from the FSI on the interface and the nonlocal interaction between unit cells. The proposed non‐Hermitian framework, involving the interplay of sound in fluids and solids, is expected to open up new possibilities for exploring unique non‐Hermitian physics and underwater acoustic applications.

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Effect of Poisson's loss factor of rubbery material on underwater sound absorption of anechoic coatings

Cited by 45 publications

References 46 publications

Theoretical requirements and inverse design for broadband perfect absorption of low-frequency waterborne sound by ultrathin metasurface

Theoretical requirements and inverse design for broadband perfect absorption of low-frequency waterborne sound by ultrathin metasurface

Analysis of Sound Absorption Performance of Underwater Acoustic Coating considering Different Poisson’s Ratio Values

Underwater Scattering Exceptional Point by Metasurface with Fluid‐Solid Interaction

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