Oblique incidence sound transmission through multi-panel structures lined with elastic porous materials

Bolton, J Stuart; Shiau, Nae-Ming

doi:10.2514/6.1987-2660

Cited by 8 publications

(4 citation statements)

References 5 publications

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“…It may be noticed that the effect of the decoupling was previously pointed out in Refs [15] and [16), for different configurations, and observed by Roland and Guilbert [18] for the case of the presented glass wool bonded on to a plate of concrete. where W is given by eqn (7.108).…”

Section: Sound Transmission Of Plane Waves Mrough Layered Materialsmentioning

confidence: 82%

“…For the case of elastic solid layers made up of composite materials which are generally non-isotropic, the representation by plates can be a convenient approximate solution of a complicated problem. Several configurations including air, plates and porous materials were studied by Bolton and Shiau [15] and Shiau et af. [16].…”

Section: Sound Transmission Of Plane Waves Mrough Layered Materialsmentioning

confidence: 99%

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Prediction of Surface Impedance and Sound Transmission for Multilayered Porous Media

Allard¹

1993

Propagation of Sound in Porous Media

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Section: Sound Transmission Of Plane Waves Mrough Layered Materialsmentioning

confidence: 82%

Section: Sound Transmission Of Plane Waves Mrough Layered Materialsmentioning

confidence: 99%

Prediction of Surface Impedance and Sound Transmission for Multilayered Porous Media

Allard¹

1993

Propagation of Sound in Porous Media

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“…Many sound transmission studies have been conducted on structures lined with porous materials. Bolton et al, 3 Bolton and Shiau, 4,5 Bolton and Green, 14 and Becot and Sgard 15 investigated an analytical model to predict sound transmission through double structure panels lined with porous layers simulating a simplified aircraft fuselage. Other researchers developed various numerical methods to analyze sound radiation and transmission by elastic structures covered by porous elastic layers.…”

Section: Transmission Loss and Noise Reduction Factorsmentioning

confidence: 99%

Development of an analytical solution of modified Biot’s equations for the optimization of lightweight acoustic protection

Kanfoud

Hamdi

Bécot³

et al. 2009

The Journal of the Acoustical Society of America

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During lift-off, space launchers are submitted to high-level of acoustic loads, which may damage sensitive equipments. A special acoustic absorber has been previously integrated inside the fairing of space launchers to protect the payload. A new research project has been launched to develop a low cost fairing acoustic protection system using optimized layers of porous materials covered by a thin layer of fabric. An analytical model is used for the analysis of acoustic wave propagation within the multilayer porous media. Results have been validated by impedance tube measurements. A parametric study has been conducted to determine optimal mechanical and acoustical properties of the acoustic protection under dimensional thickness constraints. The effect of the mounting conditions has been studied. Results reveal the importance of the lateral constraints on the absorption coefficient particularly in the low frequency range. A transmission study has been carried out, where the fairing structure has been simulated by a limp mass layer. The transmission loss and noise reduction factors have been computed using Biot's theory and the local acoustic impedance approximation to represent the porous layer effect. Comparisons between the two models show the frequency domains for which the local impedance model is valid.

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“…These methods are very efficient in the low frequency range, have to be adapted to be efficient in the medium frequency range and can not be used in the high frequencies in the state of the art. For simple structures, analytical methods can be used for the medium and high frequency ranges (see for instance [24,[42][43][44][45][46][47][48]). …”

Section: Introductionmentioning

confidence: 99%

Equivalent acoustic impedance model. Part 2: analytical approximation

Faverjon¹,

Soize²

2004

Journal of Sound and Vibration

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To cite this version:B. Faverjon, Christian Soize. Equivalent acoustic impedance model. Part 2: analytical approximation. Journal of Sound and Vibration, Elsevier, 2004, 276 (3-5) In the context of the prediction of noise levels in vibroacoustic systems, numerical models or analytical models can be developed. Generally, numerical models are adapted to the low and medium frequency ranges and analytical models to the medium and high frequency ranges. For analytical models, a classical approximation consists in modelling the multilayer system by an equivalent acoustic impedance. This paper deals with a multilayer system constituted of a porous medium inserted between two thin plates. Part I of this paper is devoted to the experiments performed and to the development of a probabilistic algebraic model for the equivalent acoustic impedance. In the present Part II, an analytical method is constructed for this multilayer system. This method consists in introducing the unbounded medium in the plane directions x 1 and x 2 while the medium is bounded in the x 3 direction. A two-dimensional space Fourier transform introducing the wave vector coordinates k 1 and k 2 is used. For a given frequency and for k 1 and k 2 fixed, the boundary value problem in x 3 is constituted of 12 differential equations in x 3 whose coefficients depend on k 1 and k 2 , with boundary conditions. This system of equations is solved by using adapted algebraic calculations. By inverse Fourier transform with respect to k 1 and k 2 , the equivalent acoustic impedance is deduced. The method which is proposed is not usual. Finally, a comparison of this analytical approach is compared with the experimental results.

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Oblique incidence sound transmission through multi-panel structures lined with elastic porous materials

Cited by 8 publications

References 5 publications

Prediction of Surface Impedance and Sound Transmission for Multilayered Porous Media

Prediction of Surface Impedance and Sound Transmission for Multilayered Porous Media

Development of an analytical solution of modified Biot’s equations for the optimization of lightweight acoustic protection

Equivalent acoustic impedance model. Part 2: analytical approximation

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