A low-frequency sound absorber based on micro-slit and coiled cavity

Almeida, Gildean do N.; Vergara, Erasmo F.; Barbosa, Leandro Rodrigues; Lenzi, Arcanjo; Birch, R. S.

doi:10.1007/s40430-020-02763-y

Cited by 15 publications

(3 citation statements)

References 28 publications

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“…The JCAL parameters are numerically evaluated using the two-scale asymptotic method solved with the finite element method implemented in Comsol Multiphysics 5.4 (Auriault et al, 2009). The simplex Nelder-Mead optimization method (Nelder and Mead, 1965;D'Errico, 2010) is used to find the size of the channels and the stacking sequence leading to the best acoustic absorption in Table 1. For the sake of conciseness, theory and details of the acoustic modelling and optimization of microchannels are not presented but can be found in Baptista et al (2021) and Costa-Baptista et al (2022).…”

Section: Design Of the Hybrid Materialsmentioning

confidence: 99%

“…a 600 Hz improvement over the one-layer structures and 1183 Hz below the QWRF) (Boulvert et al , 2019). Folded or coiled tubes can work as acoustic resonators (do et al , 2021; Arjunan, 2019; Setaki et al , 2014) and are interesting concepts to improve low-frequency absorption. For instance, broadband quasi-perfect sound absorption between 1150 and 2000 Hz was achieved with a folded metaporous material (Boulvert et al , 2020).…”

Section: Introductionmentioning

confidence: 99%

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Hybrid acoustic materials through assembly of tubes and microchannels: design and experimental investigation

Costa-Baptista

Fotsing

Mardjono

et al. 2023

RPJ

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Purpose The purpose of this paper is the design and experimental investigation of compact hybrid sound-absorbing materials presenting low-frequency and broadband sound absorption. Design/methodology/approach The hybrid materials combine microchannels and helical tubes. Microchannels provide broadband sound absorption in the middle frequency range. Helical tubes provide low-frequency absorption. Optimal configurations of microchannels are used and analytical equations are developed to guide the design of the helical tubes. Nine hybrid materials with 30 mm thickness are produced via additive manufacturing. They are combinations of one-, two- and four-layer microchannels and helical tubes with 110, 151 and 250 mm length. The sound absorption coefficient of the hybrid materials is measured using an impedance tube. Findings The type of microchannels (i.e. one, two or four layers), the number of rotations and the number of tubes are key parameters affecting the acoustic performance. For instance, in the 500 Hz octave band (α500), sound absorption of a 30 mm thick hybrid material can reach 0.52 which is 5.7 times higher than the α500 of a typical periodic porous material with the same thickness. Moreover, the broadband sound absorption for mid-frequencies is reasonably high with and α1000 > 0.7. The ratio of first absorption peak wavelength to structure thickness λ/T can reach 17, which is characteristic of deep-subwavelength behaviour. Originality/value The concept and experimental validation of a compact hybrid material combining a periodic porous structure such as microchannels and long helical tubes are original. The ability to increase low-frequency sound absorption at constant depth is an asset for applications where volume and weight are constraints.

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Section: Design Of the Hybrid Materialsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Hybrid acoustic materials through assembly of tubes and microchannels: design and experimental investigation

Costa-Baptista

Fotsing

Mardjono

et al. 2023

RPJ

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show abstract

“…Acoustic metamaterials [2][3][4][5][6] and acoustic metasurfaces [7][8][9][10] are typical subwavelength structures. Common structure types are Helmholtz resonators, [11][12][13] membrane resonators, 14,15) Fabry-Pérot (FP) cavities, [16][17][18][19][20][21][22] and fractal structures. 23,24) Seoung-HoBaek et al 12) combined a Helmholtz resonator with a fractal structure 23) and designed a sound-insulation metamaterial to reach an average sound-transmission loss of 16.34 dB in the frequency range of 600-1700 Hz.…”

mentioning

confidence: 99%

Sound-absorption performance of a coupled square-neck embedded Helmholtz resonator

Zhang¹,

Ke²,

Wu³

et al. 2022

Jpn. J. Appl. Phys.

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We propose a coupled square-neck embedded Helmholtz resonator (S-NEHR) with a deep-subwavelength thickness. By precisely designing each cell peak, the average sound-absorption coefficient of the nine coupled S-NEHR structures is greater than 0.9 at 300-410 Hz, and the thickness is only 1/30 of the working wavelength. Adding a microperforated panel (MPP) in front of the coupled structure enables a smaller size and larger bandwidth (500-1000 Hz). The simulation and experimental results demonstrate that the S-NEHR structure has great application prospects in engineering noise control due to its extraordinary sound-absorption properties and compact structure.

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A review on the use of microslit for various applications and its fabrication

Majumder,

Patowari

2024

J Braz. Soc. Mech. Sci. Eng.

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A low-frequency sound absorber based on micro-slit and coiled cavity

Cited by 15 publications

References 28 publications

Hybrid acoustic materials through assembly of tubes and microchannels: design and experimental investigation

Hybrid acoustic materials through assembly of tubes and microchannels: design and experimental investigation

Sound-absorption performance of a coupled square-neck embedded Helmholtz resonator

A review on the use of microslit for various applications and its fabrication

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