A note on the relationship between the sound absorption by microperforated panels and panel/membrane-type absorbers

In order to broaden the sound absorption bandwidth of a perforated panel in the low frequency range, a lightweight membrane-type resonator is installed in the back cavity of the perforated panel to combine into a compound sound absorber (CSA). Because of the great flexibility, the membrane-type resonator can be vibrated easily by the incident sound waves passing through the holes of the perforated panel. In the low frequency range, the membrane-type resonator and the perforated panel constitute a two degrees-of-freedom (DOF)-resonant type sound absorption system, which generates two sound absorption peaks. By tuning the parameters of the membrane type resonator, a wide frequency band having a large sound absorption coefficient can be obtained. In this paper, the sound absorption coefficient of CSA is derived analytically by combining the vibration equation of the membrane-type resonator with the acoustic impedance equation of the perforated panel. The influences of the parameters of the membrane-type resonator on the sound absorption performance of the CSA are numerically analyzed. Finally, the wide band sound absorption capacity of the CSA is validated by the experimental test.

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Research on Effect of Equivalent Diameter of Voids on Sound Absorption Performance of Porous Asphalt Concrete Based on Grey Entropy Method

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.861.414 ◽

2020 ◽

Vol 861 ◽

pp. 414-420

Author(s):

Ming Xi Liu ◽

Jian Guang Xie ◽

Zhan Qi Wang ◽

Yan Ping Liu

Keyword(s):

Asphalt Concrete ◽

Sound Absorption ◽

Traffic Noise ◽

Entropy Method ◽

Equivalent Diameter ◽

Air Voids ◽

Porous Asphalt ◽

Absorption Performance ◽

The Relationship ◽

Porous Asphalt Concrete

The sound absorption performance of porous asphalt concrete (PAC) is inseparable from the sizes of voids, as different sizes of voids have different absorption effects on noise in different frequency bands. However, the relationship between the two is not clear. In this study, the equivalent diameter of voids was obtained by the proposed image segmentation algorithm based on the square area, then grey entropy method was used to analyze the effect of different equivalent diameter of voids on the sound absorption performance of PAC in the frequency range of traffic noise. The results show that with the increase of air voids, the peak and average sound absorption coefficient of PAC increase, the sound absorption performance of PAC is improved; and the sound absorption performance of PAC is mainly affected by the equivalent diameter of voids of 3-4mm.

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Analysis of sound absorption behavior of polyester fiber material faced with microperforated panels

The Journal of the Acoustical Society of America ◽

10.1121/1.4805497 ◽

2013 ◽

Vol 133 (5) ◽

pp. 3309-3309 ◽

Cited By ~ 1

Author(s):

Davide Borelli ◽

Corrado Schenone ◽

Ilaria Pittaluga

Keyword(s):

Sound Absorption ◽

Fiber Material ◽

Polyester Fiber ◽

Microperforated Panels

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Diffuse Field Sound Absorption of Microperforated Panels with Special Backings

SAE International Journal of Vehicle Dynamics Stability and NVH ◽

10.4271/2017-01-1876 ◽

2017 ◽

Vol 1 (2) ◽

pp. 464-470 ◽

Cited By ~ 1

Author(s):

Weiyun Liu ◽

David W. Herrin ◽

Emanuele Bianchini

Keyword(s):

Sound Absorption ◽

Microperforated Panels ◽

Field Sound

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Marble Powder Blended Utilization Polyurethane as Soundproof Materials

Jurnal Inotera ◽

10.31572/inotera.vol6.iss1.2021.id131 ◽

2021 ◽

Vol 6 (1) ◽

pp. 30-36

Author(s):

Yusrizal MT ◽

Muhammad Ali ◽

Nuzuli Fitriadi ◽

Irwansyah Syam ◽

Balkhaya ◽

...

Keyword(s):

Absorption Coefficient ◽

Test Specimen ◽

Sound Absorption ◽

Sound Absorption Coefficient ◽

Mass Composition ◽

Test Results ◽

Polyurethane Composite ◽

Alternative Material ◽

Marble Powder ◽

The Relationship

As technology advances, the development of equipment used by humans is increasing and most of the equipment produces unwanted sounds that cause noise. To overcome this, an alternative material for soundproofing is needed which is relatively cheap and easily available in the community by using marble powder as a polyurethane mixture in soundproof panels. The purpose of this study was to determine the effect of the sound absorption coefficient value and to determine the relationship between the frequency of the sound source and the sound absorption coefficient of acoustic materials using marble powder mixed with polyurethane in different compositions. The sound absorption test in this study was carried out using a two-microphone impedance tube and has a frequency limit of 125 Hz - 4000 Hz, variations in the mass composition of marble and polyurethane powder 1: 1, 1: 2 and 1: 3 with a thickness of 5 cm, 3cm and 1 cm. Then the test results of the 1: 1 test specimen, the lowest sound absorption coefficient value was obtained 0.10 0.73 cm-1 at a thickness of 1 cm with a frequency of 4000 Hz and the highest was 0.73 cm-1 at a thickness of 5 cm with a frequency of 125 Hz, the test results 1: 2 test specimen, the lowest sound absorption coefficient value is 0.29 cm-1 at a thickness of 5 cm at a frequency of 4000 Hz and the highest is 0.67 cm-1 at a thickness of 5 cm at 250 Hz, then the test results of the test specimen are 1: 3 values The lowest sound absorption coefficient was 0.24 at a thickness of 1 cm at a frequency of 4000 Hz and the highest was 0.71 at a thickness of 5 cm at a frequency of 250 Hz. For the comparison of the sound absorption coefficient values based on the composition and thickness, the lowest and highest sound absorption coefficient values are found in 1: 1 specimens with a thickness of 1 cm and 5 cm with the best sound absorption coefficient values on average at a frequency of 500 Hz, but in material 1:2 and 1:3 obtained the sound absorption coefficient values are in between on the grounds that the thicker the material, the higher the sound absorption coefficient value. Thus it can be concluded that the polyurethane composite material mixed with marble powder can be used as a sound absorbing panel material, especially in a 1: 1 composition

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Comparison of multiple-layer versus multiple-cavity microperforated panels for sound absorption at low frequency

Noise Control Engineering Journal ◽

10.3397/1/376931 ◽

2021 ◽

Vol 69 (4) ◽

pp. 341-350

Author(s):

Pedro Cobo ◽

Francisco Simón ◽

Carlos Colina

Keyword(s):

Sound Absorption ◽

Low Frequency ◽

Single Layer ◽

Helmholtz Resonator ◽

Layer Versus ◽

Low Frequencies ◽

High Frequencies ◽

Multiple Layer ◽

Band Absorption ◽

Microperforated Panels

Microperforated panels (MPPs) are recognized as suitable absorbers for noise control applications demanding special clean and health requirements.While it is relatively easy to design single-layer MPPs for sound absorption in one-to-two octave bands at medium-high frequencies, the performance for low frequencies (below 600 Hz) leads to a rather narrow-band absorption, similar to that of a Helmholtz resonator. However, multiple-layer MPPs can be designed as sound absorbers that yield low-frequency absorption in a wide frequency band. Recently, multiple-cavity perforated panels have been proposed to improve the performance of MPPs in the low-frequency range. In this article, the capability of multiple-layer and multiple-cavity MPPs to provide sound absorption at low frequencies is analyzed.

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