Enhancing of broadband sound absorption through soft matter

Ma, Fuyin; Wang, Chang; Du, Yang; Zhu, Zicai; Wu, Jiu Hui

doi:10.1039/d1mh01685g

Cited by 48 publications

(19 citation statements)

References 34 publications

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“…The sound absorption performance of acoustic metamaterial is mainly decided by its structural parameters, which can obtain a certain frequency bandwidth with a certain size [ 10 , 11 , 12 , 13 , 14 ]. Wu et al had proposed an acoustic metamaterial for the low frequency absorption through the combination of three nested square split tubes with the inverted opening direction, and three absorption peaks at the 230 Hz, 320 Hz, and 500 Hz were obtained by adjusting the geometric parameters [ 10 ].…”

Section: Introductionmentioning

confidence: 99%

“…The microperforated acoustic metamaterial with honeycomb-corrugation hybrid core was developed by Zhang et al [ 11 ] to achieve the broadband low frequency noise control, and the influence of its key geometrical parameters on the sound absorption was systematically investigated, such as the upper facesheet thickness, perforation diameter and corrugated plate thickness. Ma et al [ 12 ] had developed a metamaterial design method that used soft matter for constructing a unique soft acoustic boundary to effectively improve the sound absorption performance. Yang and Sheng [ 13 ] had investigated the sound absorption structures from porous media to acoustic metamaterials, and absorption performance of each kind of absorber was summarized.…”

Section: Introductionmentioning

confidence: 99%

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Development of Adjustable Parallel Helmholtz Acoustic Metamaterial for Broad Low-Frequency Sound Absorption Band

Yang

Shen

et al. 2022

Materials

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For the common difficulties of noise control in a low frequency region, an adjustable parallel Helmholtz acoustic metamaterial (APH-AM) was developed to gain broad sound absorption band by introducing multiple resonant chambers to enlarge the absorption bandwidth and tuning length of rear cavity for each chamber. Based on the coupling analysis of double resonators, the generation mechanism of broad sound absorption by adjusting the structural parameters was analyzed, which provided a foundation for the development of APH-AM with tunable chambers. Different from other optimization designs by theoretical modeling or finite element simulation, the adjustment of sound absorption performance for the proposed APH-AM could be directly conducted in transfer function tube measurement by changing the length of rear cavity for each chamber. According to optimization process of APH-AM, The target for all sound absorption coefficients above 0.9 was achieved in 602–1287 Hz with normal incidence and that for all sound absorption coefficients above 0.85 was obtained in 618–1482 Hz. The distributions of sound pressure for peak absorption frequency points were obtained in the finite element simulation, which could exhibit its sound absorption mechanism. Meanwhile, the sound absorption performance of the APH-AM with larger length of the aperture and that with smaller diameter of the aperture were discussed by finite element simulation, which could further show the potential of APH-AM in the low-frequency sound absorption. The proposed APH-AM could improve efficiency and accuracy in adjusting sound absorption performance purposefully, which would promote its practical application in low-frequency noise control.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Development of Adjustable Parallel Helmholtz Acoustic Metamaterial for Broad Low-Frequency Sound Absorption Band

Yang

Shen

et al. 2022

Materials

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“…The lattice constant of the AMMs can be deep subwavelength because of the local resonance mechanism, and therefore reveals obvious advantages in the low-frequency acoustic field (Liu et al, 2000). Various AMMS structures have been proposed to achieve acoustic wave manipulation or absorption functions, including a Helmholtz resonator (HR) (Kim et al, 2006;Jimenez et al, 2017;Shao et al, 2020;Ma et al, 2022), membrane-type acoustic metamaterial (MAM) (Mei et al, 2012;Ma et al, 2013;Yang et al, 2016), metasurface (Li et al, 2017;Chen et al, 2019;Liu et al, 2021), and acoustic black hole (ABH) (Zhao et al, 2014;Pelat et al, 2020;Gao et al, 2021).…”

Section: Introductionmentioning

confidence: 99%

Barrier-free duct muffler for low-frequency sound absorption

Gao

Hu²,

Mei

et al. 2022

Front. Mater.

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We demonstrate a duct muffler design that operates in the low-frequency range (<2000 Hz). The device contained a pair of coupled annular Helmholtz resonators (HRs) and porous material stuffing. HRs were installed as side branches of a circular tube to avoid affecting the ventilation. Porous materials were employed to form an asymmetric intrinsic loss in the HR pair and enable the device to achieve perfect sound absorption. An analytical model based on the temporal coupled-mode theory was derived, and a numerical simulation technique for structural design was introduced and verified. The experimental study demonstrated the effectiveness of the design methodology and illustrated that the device can achieve near-perfect sound absorption in the desired frequency range. A symmetrical configuration of the HRs also experimentally proved to be able to conduct sound absorption for sound incident from both sides of the duct. This study 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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“…The boundary constraints between the eyeball and the skull may affect the refractive and reflective waves, especially, the frequencies dominated by the geometry and material properties of the soft matter 24 . In anatomy, the space between the eyeball and the skull is a conical structure and contains the muscles, the optic nerve, and fat.…”

Section: Discussionmentioning

confidence: 99%

Eye orbit effects on eyeball resonant frequencies and acoustic tonometer measurements

Shih

Sung

et al. 2022

Sci Rep

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The eye orbit has mechanical and acoustic characteristics that determine resonant frequencies and amplify acoustic signals in certain frequency ranges. These characteristics also interfere with the acoustic amplitudes and frequencies of eyeball when measured with an acoustic tonometer. A model in which a porcine eyeball was embedded in ultrasonic conductive gel in the orbit of a model skull was used to simulate an in vivo environment, and the acoustic responses of eyeballs were detected. The triggering source was a low-power acoustic speaker contacting the occipital bone, and the detector was a high-resolution microphone with a dish detecting the acoustic signals without contacting the cornea. Dozens of ex vivo porcine eyeballs were tested at various intraocular pressure levels to detect their resonant frequencies and acoustic amplitudes in their power spectra. We confirmed that the eyeballs’ resonant frequencies were proportional to intraocular pressure, but interference from orbit effects decreased the amplitudes in these resonant frequency ranges. However, we observed that the frequency amplitudes of eyeballs were correlated with intraocular pressure in other frequency ranges. We investigated eye orbit effects and demonstrated how they interfere with the eyeball’s resonant frequencies and frequency amplitudes. These results are useful for developing advanced acoustic tonometer.

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Enhancing of broadband sound absorption through soft matter

Abstract: An artificial acoustic soft boundary on the inner wall of an absorber is constructed by an extremely soft PVC gel, and excellent sound absorption enhancement in the broadband frequency range is obtained.

Cited by 48 publications

References 34 publications

Development of Adjustable Parallel Helmholtz Acoustic Metamaterial for Broad Low-Frequency Sound Absorption Band

Development of Adjustable Parallel Helmholtz Acoustic Metamaterial for Broad Low-Frequency Sound Absorption Band

Barrier-free duct muffler for low-frequency sound absorption

Eye orbit effects on eyeball resonant frequencies and acoustic tonometer measurements

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