Acoustical properties of air-saturated porous material with periodically distributed dead-end pores

Leclaire, Philippe; Umnova, Olga; Dupont, Thomas; Panneton, Raymond

doi:10.1121/1.4916712

Cited by 40 publications

(43 citation statements)

References 12 publications

(7 reference statements)

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“…This last type of metamaterials [10][11][12] makes use of its strong dispersion for generating slow-sound conditions inside the material and, therefore, drastically decreasing frequency of the absorption peaks. Hence, the structure thickness becomes deeply sub-wavelength.…”

mentioning

confidence: 99%

Ultra-thin metamaterial for perfect and quasi-omnidirectional sound absorption

Jiménez

Huang

Romero‐García

et al. 2016

Applied Physics Letters

296

172

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Using the concepts of slow sound and of critical coupling, an ultra-thin acoustic metamaterial panel for perfect and omnidirectional absorption is theoretically and experimentally conceived in this work. The system is made of a rigid panel with a periodic distribution of thin closed slits, the upper wall of which is loaded by Helmholtz Resonators (HRs). The presence of resonators produces a slow sound propagation shifting the resonance frequency of the slit to the deep sub-wavelength regime (λ/88). By controlling the geometry of the slit and the HRs, the intrinsic visco-thermal losses can be tuned in order to exactly compensate the energy leakage of the system and fulfill the critical coupling condition to create the perfect absorption of sound in a large range of incidence angles due to the deep subwavelength behavior. * noe.jimenez@univ-lemans.fr 1 arXiv:1606.07776v1 [physics.class-ph] Jun 2016The ability to perfectly absorb an incoming wave field in a sub-wavelength material is advantageous for several applications in wave physics as energy conversion [1], time reversal technology [2], coherent perfect absorbers [3] or soundproofing [4] among others. The solution of this challenge requires to solve a complex problem: reducing the geometric dimensions of the structure while increasing the density of states at low frequencies and finding the good conditions to match the impedance to the background medium.A successful approach for increasing the density of states at low frequencies with reduced dimensions is the use of metamaterials. Recently, several possibilities based on these systems have been proposed to design sound absorbing structures which can present simultaneously sub-wavelength dimensions and strong acoustic absorption. One strategy to design these sub-wavelength systems consists of using space-coiling structures [5,6]. Another way is to use sub-wavelength resonators as membranes [4,7] or Helmholtz resonators (HRs) [8,9].Recently, a new type of sub-wavelength metamaterials based on the concept of slow sound propagation have been used to the same purpose. This last type of metamaterials [10][11][12] makes use of its strong dispersion for generating slow-sound conditions inside the material and, therefore, drastically decreasing frequency of the absorption peaks. Hence, the structure thickness becomes deeply sub-wavelength. All of these structures, however, while they bring potentially solutions to reduce the geometric dimensions, face the challenge of impedance mismatch to the background medium.The interaction of an incoming wave with a lossy resonant structure, in particular the impedance matching with the background field, is one of the most studied process in the field of wave physics [1][2][3]. These open systems, at the resonant frequency, are characterized by both the leakage rate of energy (i.e., the coupling of the resonant elements with the propagating medium), and the intrinsic losses of the resonator. The balance between the leakage and the losses activates the condition of critic...

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mentioning

confidence: 99%

Ultra-thin metamaterial for perfect and quasi-omnidirectional sound absorption

Jiménez

Huang

Romero‐García

et al. 2016

Applied Physics Letters

296

172

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“…Thus, the main limitation of porous material-based absorbers yields in the sound speed inside the absorbers, which is on the same order as the one in the air medium: to efficiently absorb low-frequency sound, the thickness of the layer must be large, because at these frequencies the wavelength in air is on the order of several meters. Peculiar absorption properties are also encountered in composite structures like double porosity materials [2], dead-end porosity materials [3,4], or chirped layered structures [5]. However, it is of special interest to design materials and structures in the form of thin panels (i.e., much smaller than the characteristic wavelength).…”

Section: Introductionmentioning

confidence: 99%

“…These specific materials are artificial structures composed of an arrangement of resonant unit cells-smaller than the characteristic wavelength-that present effective properties not observed in the materials that compose the structure. Examples of such absorbers are metaporous materials [6][7][8][9], metamaterials composed of membrane-type resonators [10][11][12][13], Helmholtz resonators (HRs) [13][14][15][16], and quarter-wavelength resonators (QWRs) [4,[17][18][19]. These last types of metamaterials [4,[15][16][17][18]] make use of strong dispersion, giving rise to slow-sound propagation inside the material.…”

Section: Introductionmentioning

confidence: 99%

Iridescent Perfect Absorption in Critically-Coupled Acoustic Metamaterials Using the Transfer Matrix Method

et al. 2017

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Abstract:The absorption performance of a locally-reacting acoustic metamaterial under oblique incidence is studied. The metamaterial is composed of a slotted panel, each slit being loaded by an array of Helmholtz resonators. The system is analytically studied using the transfer matrix method, accounting for the viscothermal losses both in the resonator elements and in the slits, allowing the representation of the reflection coefficient in the complex frequency plane. We show that by tuning the geometry of the metamaterial, perfect absorption peaks can be obtained on demand at selected frequencies and different angles of incidence. When tilting the incidence angle, the peaks of perfect absorption are shifted in frequency, producing an acoustic iridescence effect similar to the optic iridescence achieved by incomplete band gap. Effectively, we show that in this kind of locally-reacting metamaterial, perfect and omnidirectional absorption for a given frequency is impossible to achieve because the metamaterial impedance does not depend on the incidence angle (i.e., the impedance is a locally reacting one). The system is interpreted in the complex frequency plane by analysing the trajectories of the zeros of the reflection coefficient. We show that the trajectories of the zeros do not overlap under oblique incidence, preventing the observation of perfect and omnidirectional absorption in locally reacting metamaterials. Moreover, we show that for any locally resonant material, the absorption in diffuse field takes a maximal value of 0.951, which is achieved by a material showing perfect absorption for an incidence angle of 50.34 degrees.

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“…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%

“…In order to enhance low frequency sound absorption, quarter wavelength [9,10] (eventually coiled [11]), split ring and Helmholtz resonators [12,13,14,15,6] have been embedded in porous materials. 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).…”

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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Acoustical properties of air-saturated porous material with periodically distributed dead-end pores

Cited by 40 publications

References 12 publications

Ultra-thin metamaterial for perfect and quasi-omnidirectional sound absorption

Ultra-thin metamaterial for perfect and quasi-omnidirectional sound absorption

Iridescent Perfect Absorption in Critically-Coupled Acoustic Metamaterials Using the Transfer Matrix Method

Additional Sound Absorption Within a Poroelastic Lamella Network Under Oblique Incidence

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