Asymmetric sound absorption achieved by double-layer piezoelectric metamaterials with tunable shunt circuit

Gu, Limin; Zhao, Chunyu; Wang, Kaiqi; Li, Senlei; Wang, Xiaole; Huang, Zhenyu

doi:10.1063/5.0067669

Cited by 6 publications

(1 citation statement)

References 24 publications

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“…This generated the thermal viscosity effect between the moving air and the wall of the rear chamber and the thermal viscosity between the moving air and the wall of the aperture. Additionally, it resulted in the conversion of sound energy to heat energy and the increase in the temperature of the air in both the chamber and the aperture [23][24][25][26], which could be judged from the distribution of the temperature in Figure 3d. It can be seen in Figure 3e that, along with the decrease in l, the resonance frequency shifted to the high frequency direction and the peak sound absorption coefficient rose gradually.…”

Section: Influence Of the Tunable Aperturementioning

confidence: 99%

Adjustable Sound Absorber of Multiple Parallel-Connection Helmholtz Resonators with Tunable Apertures Prepared by Low-Force Stereolithography of Photopolymer Resin

Yang

Shen

et al. 2022

Polymers

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The variable noise spectrum for many actual application scenarios requires a sound absorber to adapt to this variation. An adjustable sound absorber of multiple parallel-connection Helmholtz resonators with tunable apertures (TA–MPCHRs) is prepared by the low-force stereolithography of photopolymer resin, which aims to improve the applicability of the proposed sound absorber for noise with various frequency ranges. The proposed TA–MPCHR metamaterial contains five metamaterial cells. Each metamaterial cell contains nine single Helmholtz resonators. It is treated as a basic structural unit for an array arrangement. The tunable aperture is realized by utilizing four segments of extendable cylindrical chambers with length l0, which indicates that the length of the aperture l is in the range of [l0, 4l0], and that it is tunable. With a certain group of specific parameters for the proposed TA–MPCHR, the influence of the tunable aperture with a variable length is investigated by acoustic finite element simulation with a two-dimensional rotational symmetric model. For the given noise spectrum of certain actual equipment with four operating modes, the TA–MPCHR sample with a limited total thickness of 40 mm is optimized, which is made of photopolymer resin by the low-force stereolithography, and its actual average sound absorption coefficients for the frequency ranges of 500–800 Hz, 550–900 Hz, 600–1000 Hz and 700–1150 Hz reach 0.9203, 0.9202, 0.9436 and 0.9561, respectively. Relative to common non-adjustable metamaterials, the TA–MPCHR made of photopolymer resin can reduce occupied space and improve absorption efficiency, which is favorable in promoting its practical applications in the noise pollution prevention.

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Section: Influence Of the Tunable Aperturementioning

confidence: 99%

Adjustable Sound Absorber of Multiple Parallel-Connection Helmholtz Resonators with Tunable Apertures Prepared by Low-Force Stereolithography of Photopolymer Resin

Yang

Shen

et al. 2022

Polymers

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Progress of low-frequency sound absorption research utilizing intelligent materials and acoustic metamaterials

et al. 2021

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An ultra-thin ventilated metasurface with extreme asymmetric absorption

Zhu

Long

Liu

et al. 2022

Applied Physics Letters

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Recent progress in minimizing sound absorbers is driven by their great scientific significance and engineering value; however, compact devices for low-frequency sound are still challenging. Here, we construct an ultra-thin metasurface by parallel connecting resonators with high dissipation loss to a non-resonant reactance-dominated boundary (RDB) with high radiation loss, which realizes extreme absorption asymmetry at the exceptional point of scattering eigenvalue. We develop a parallel transfer matrix method to design the system, and a deep-subwavelength absorber (the operating wavelength is 120 times of its thickness) with 99.2% and 0.5% absorption for sound incident from opposite ports is achieved. The extreme absorption asymmetry is ascribed to the distinct coupling between the RDB and resonant meta-atom in an unbalanced dissipating state with excellent robustness against geometrical reconfigurations originated from the broadband near-unity reflection characteristics of the RDB. In particular, the proposed strategy brings the design of a degree of freedom rather than typical multiple resonant modes, and an extensible prototype showing >90% (<1%) absorptance for left- (right-) incidence within a wavelength from 23.3 to 18 times its thickness is demonstrated.

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Asymmetric sound absorption achieved by double-layer piezoelectric metamaterials with tunable shunt circuit

Cited by 6 publications

References 24 publications

Adjustable Sound Absorber of Multiple Parallel-Connection Helmholtz Resonators with Tunable Apertures Prepared by Low-Force Stereolithography of Photopolymer Resin

Adjustable Sound Absorber of Multiple Parallel-Connection Helmholtz Resonators with Tunable Apertures Prepared by Low-Force Stereolithography of Photopolymer Resin

Progress of low-frequency sound absorption research utilizing intelligent materials and acoustic metamaterials

An ultra-thin ventilated metasurface with extreme asymmetric absorption

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