Multiple slow waves in metaporous layers for broadband sound absorption

Yang, Jieun; Lee, Joong Seok; Kim, Yoon Young

doi:10.1088/1361-6463/50/1/015301

Cited by 69 publications

(36 citation statements)

References 30 publications

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“…; Electronic mail: benoit.nennig@supmeca.fr is by multi-layering 15,16 . Other alternative solution is to embed periodic inclusions 17,18 or subwavelength resonators [19][20][21][22][23] to create metaporous materials (resonant inclusions embedded in a porous matrix). Thanks to this approach, it is possible to get a total absorption 24 below the quarter wavelength frequency and to widen the absorption in a specified frequency range.…”

Section: Introductionmentioning

confidence: 99%

Sound attenuation optimization using metaporous materials tuned on exceptional points

Xiong¹,

Nennig²,

Aurégan³

et al. 2017

The Journal of the Acoustical Society of America

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A metamaterial composed of a set of periodic rigid resonant inclusions embedded in a porous lining is investigated to enhance the sound attenuation in an acoustic duct at low frequencies. A transmission loss peak is observed on the measurements and corresponds to the crossing of the lower two Bloch modes of an infinite periodic material. Numerical parametric studies show that the optimum modal attenuation can be achieved at the exceptional point in the parameter plane of inclusion position and frequency, where the two lower modes merge.

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Section: Introductionmentioning

confidence: 99%

Sound attenuation optimization using metaporous materials tuned on exceptional points

Xiong¹,

Nennig²,

Aurégan³

et al. 2017

The Journal of the Acoustical Society of America

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“…For instance, rigid splitters [17] can be replaced by air gaps, leading to a horizontal lamella network of different sizes that can be excited at all incidence angles and be tuned at different frequencies to enlarge the frequency range of the additional absorption. The network should also be designed by optimizing its properties involved in double porosity dissipation [39] with air gap size, periodicity and material resistivity or by applying critical coupling [20] to the bending mode to obtain maximum sound absorption.…”

Section: Resultsmentioning

confidence: 99%

“…Such resonators can dramatically boost sound absorption provided that the resonator frequency is above the Biot frequency (i.e., transition from a viscous to an inertial regime). They can also be combined to create a slow sound channel [16,10,17,18].…”

Section: Introductionmentioning

confidence: 99%

Additional Sound Absorption Within a Poroelastic Lamella Network Under Oblique Incidence

Dauchez¹,

Nennig²,

Robin³

2018

Acta Acustica united with Acustica

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To tackle the lack of efficiency of passive sound absorbing treatments in the low frequency range, a specific arrangement of a poroelastic material is proposed. Compared with the usual uniform layout, giving a lamella network structure to a material provides additional sound absorption below the quarter wavelength resonance frequency at oblique incidence. This is demonstrated experimentally on a sample made of melamine foam lamellas. A numerical approach that incorporates geometric periodicity highlights the mechanisms involved in this additional dissipation, achieved by combining structural and viscous dissipation within the lamellas. The shear and bending resonances of the lamellas can be excited at oblique incidence. The frequency of the shear resonance is related to the thickness of the sample, whereas the bending resonance is also a function of the width of the lamellas. These simple dimensional parameters allow adjustable tuning of the associated frequencies at which additional sound absorption can be obtained.

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“…A classical way of improving absorption is to insert an airgap between the material layer and its rigid backing but this may not be acceptable if space is limited. Alternatives include impedance matching [2], partitioning [3,4] and periodically-spaced inclusions which introduce additional scattering and dissipation mechanisms [5,6].…”

Section: Introductionmentioning

confidence: 99%