Tunable and broadband asymmetric sound absorptions with coupling of acoustic bright and dark modes

Long, Houyou; Liu, Chen; Shao, Chen; Cheng, Ying; Tao, Jianmin; Qiu, Xiaojun; Liu, Xiaojun

doi:10.1016/j.jsv.2020.115371

Cited by 55 publications

(24 citation statements)

References 48 publications

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“…Similar effects occur in perfect sound absorbers without ventilation openings which completely reflect sounds from the back 13 – 24 . Asymmetric sound absorption has also been observed in certain asymmetric acoustic waveguides 39 – 42 . However, since resonators are placed outside the waveguides, those designs cannot be directly applied to construct metasurfaces.…”

mentioning

confidence: 88%

Bilayer ventilated labyrinthine metasurfaces with high sound absorption and tunable bandwidth

Luo

Zhao

et al. 2021

Sci Rep

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The recent advent of acoustic metamaterials offers unprecedented opportunities for sound controlling in various occasions, whereas it remains a challenge to attain broadband high sound absorption and free air flow simultaneously. Here, we demonstrated, both theoretically and experimentally, that this problem can be overcome by using a bilayer ventilated labyrinthine metasurface. By altering the spacing between two constituent single-layer metasurfaces and adopting asymmetric losses in them, near-perfect (98.6%) absorption is achieved at resonant frequency for sound waves incident from the front. The relative bandwidth of absorption peak can be tuned in a wide range (from 12% to 80%) by adjusting the open area ratio of the structure. For sound waves from the back, the bilayer metasurface still serves as a sound barrier with low transmission. Our results present a strategy to realize high sound absorption and free air flow simultaneously, and could find applications in building acoustics and noise remediation.

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mentioning

confidence: 88%

Bilayer ventilated labyrinthine metasurfaces with high sound absorption and tunable bandwidth

Luo

Zhao

et al. 2021

Sci Rep

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“…The reflector, whose impedance is much less than the surrounding medium impedance, is equivalent to a soft acoustic boundary and thus preventing the wave from transmitting by reflecting the incident wave. Long et al 33 proposed HR designs with weak damping and high dissipation respectively by carefully adjusting the dimension of cavity and neck of the HRs. Another approach of tuning the dissipation is to employ porous materials.…”

Section: Introductionmentioning

confidence: 99%

Barrier-Free Duct Muffler For Low-Frequency Sound Absorption

Gao

Hu²,

Murai

et al. 2022

Preprint

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We demonstrate a duct muffler design operating at frequency range that lower than 2000Hz. The device is composed of coupled annular Helmholtz Resonators (HRs) and installed as side branch of a circular ventilation tube to avoid affecting the ventilation. Porous material is employed for the purpose of generating asymmetric intrinsic loss status of the HR. Analytical model based on temporal coupled-mode theory is introduced and numerical simulation technique for structure design are introduced and verified. Experimental study verifies the effectiveness of the design methodology and illustrate that the device can achieve near perfect sound absorption in the desired frequency range. A symmetry configuration of HRs also experimentally proved to be able to conduct sound absorption for sound incident from both sides of the duct. This work provides a solid foundation for the application of the designed muffler and an analytical explanation of the corresponding sound absorption mechanisms.

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“…Traditional materials for sound-absorbing, such as porous materials, 1 have tiny inherent dissipation, making it challenging to absorb low-frequency noise with a subwavelength structure. Nevertheless, the subwavelength acoustic metasurfaces, such as Helmholtz resonator (HR), [2][3][4][5][6][7][8][9][10][11][12][13][14][15] micro-perforated plates (MPPs), [16][17][18] coiling space, [19][20][21][22] and membrane, 9,[23][24][25][26] manifest a promising prospect in absorbing low-frequency noise in the past years. Besides, acoustic metasurfaces with extraordinary physical properties are widely adapted to energy harvest, 27 time reversal, 28 acoustic focusing, 29 and acoustic holography.…”

Section: Introductionmentioning

confidence: 99%

A parameter design method for multifrequency perfect sound-absorbing metasurface with critical coupled Helmholtz resonator

Wei

Chu

et al. 2021

Journal of Low Frequency Noise, Vibration and Active Control

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The low-frequency harmonic components of urban substation noise are easy to annoy the residents. Multi-frequency perfect sound-absorbing metasurface based on the Helmholtz resonator (HR) is an alternative solution to suppress the low-frequency harmonic noise. This paper proposes an efficient design method of structural parameter for the multi-frequency perfect sound-absorbing metasurface. Taking the perfect sound absorption at the target frequency as objective and the structural parameters of HR as optimization variables, the structural parameter optimization model of multi-frequency perfect sound-absorbing metasurface is established and solved by the sequential quadratic programming algorithm. The proposed design method effectively overcomes the deterioration of sound absorption performance caused by the combined design of multiple perfect sound absorption units. Utilizing the proposed method, we designed a multi-frequency perfect sound-absorbing metasurface to absorb the four harmonic components of an urban substation noise simultaneously. The finite element simulation results and the experimental results of the physical sample indicate that the designed multi-frequency perfect sound-absorbing metasurface can satisfy critical coupling to achieve perfect sound absorption at all target frequencies.

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Tunable and broadband asymmetric sound absorptions with coupling of acoustic bright and dark modes

Cited by 55 publications

References 48 publications

Bilayer ventilated labyrinthine metasurfaces with high sound absorption and tunable bandwidth

Bilayer ventilated labyrinthine metasurfaces with high sound absorption and tunable bandwidth

Barrier-Free Duct Muffler For Low-Frequency Sound Absorption

A parameter design method for multifrequency perfect sound-absorbing metasurface with critical coupled Helmholtz resonator

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