Modified two-thickness method for measurement of the acoustic properties of porous materials

Kim, Bo Seung; Seong, Yeonuk; Park, Junhong

doi:10.1016/j.apacoust.2018.10.033

Cited by 7 publications

(3 citation statements)

References 12 publications

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“…Porous sound absorption materials are composed of a large number of pores, cracks, or cavities, allowing sound waves to enter the material [23,24]. Te sound energy is dissipated by the heat loss caused by the friction between air molecules and the pore wall, and the viscosity of the airfow in the material causes the viscosity loss, the sound energy can be greatly reduced, and the porous material exhibits broadband sound absorption at 1000-6000 Hz [25][26][27]. Te resonant sound absorption material is mainly a cavity resonance structure, and the sound absorption frequency band is narrow.…”

Section: Introductionmentioning

confidence: 99%

Study on Sound Absorption Properties of Polyvinyl Chloride (PVC) Film Multicavity Structure Materials

Zhang,

Zheng

et al. 2024

Shock and Vibration

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Since the development of industry, sound absorption and noise reduction have gradually become an urgent problem to be solved. Lightweight polymer film materials are very effective in response to sound waves, and sound waves can easily cause vibration of the film, which can convert sound energy into vibration and film friction to achieve sound absorption. The application conditions of the film material are very harsh, that is, a support body is required to fix the film and the film needs to be tensioned. The film is very thin and easy to damage. The idea of this research is to transform the film into a bubble structure and use a large number of film bubbles to form a cavity structure material. As a unit of the sound absorption structure, bubbles can avoid damage to the film. In this paper, commercial polyvinyl chloride film bubble materials are used to prepare two kinds of film multicavity structure materials, and the sound absorption performance of this film multicavity structure material is studied. The research results show that this film multicavity structure material has very excellent broadband sound absorption performance, which changes the narrow band sound absorption properties of the usual film single cavity. The average sound absorption coefficient can reach 0.84 in frequency range from 500 Hz to 6400 Hz. This structural material has a single peak sound absorption curve at the middle and low frequency bands, which is the characteristic of resonance sound absorption. And at the middle and high frequency bands, it exhibits the characteristics of broadband sound absorption. The film multicavity structure material has both cavity sound absorption and broadband sound absorption characteristics.

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Section: Introductionmentioning

confidence: 99%

Study on Sound Absorption Properties of Polyvinyl Chloride (PVC) Film Multicavity Structure Materials

Zhang,

Zheng

et al. 2024

Shock and Vibration

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“…Technical requirements for the production of polyolefin foams are defined by GOST R 56729-2015 (EN 14313: 2009)) which involves selective testing of characteristics. The main methods of studying the sound absorption of polyolefin foams are tests in a reverberation chamber [1] (GOST 31704-2011 (EN ISO 354: 2003)) and tests in an impedance tube with two or four microphones [2,3]. None of the methods regulated by the state standards allows us to assess the uneven properties of the produced sheets of polyethin foams.…”

Section: Introductionmentioning

confidence: 99%

“…Most studies of the acoustic properties of polyolefin foams are limited to the study of sound absorption under various conditions and its dependence on porosity, apparent density, tortuosity of pores, and radiation frequency [1][2][3][4][5][6][7][8][9]. A number of studies [1][2][3][4][5][6][7][8][9] show the possibility of improving the acoustic characteristics (sound absorption, sound attenuation, and vibration damping property) by optimizing the structure and synthetic formula with various inorganic and organic fillers [3,[10][11][12][13]. The influence of porosity and tortuosity of pores on the speed of sound, Poisson's ratio, elastic modulus, and radiation frequencies is studied [14][15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Nonuniformity of Elastic Properties of Sheets Made from Closed-Сell Polyolefin Foams by Acoustic Method

Bogdan

Злобин

Муравьева

et al. 2021

Prib. metody izmer.

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The widespread use of polyolefin foams in strategically important industries is due to their high thermal, sound and vibration insulation properties. The aim of the work was to evaluate the non-uniformity of elastic properties over the area of sheets of polyolefin foams of various types using the acoustic non-contact shadow amplitude method of testing and confirmation by the structural analysis method.The article presents the developed installation and a new method of non-contact acoustic testing of sheets made of closed-cell polyolefin foams based on recording the amplitude of the pulse that passed through the sheet and allowing to assess to the unevenness of its elastic properties during scanning. Studies of uneven elastic properties were carried out on sheets of closed-cell polyolefin foams of the ISOLON 500 and ISOLON 300 brands which differ in material and manufacturing technology (technique of cross-linking, method and multiplicity of foaming).It is shown that the absolute amplitude of the signal and its spread relative to the average value is affected by the structure of the foam polyolefin material and its heterogeneity over the area of the studied sheet determined by the production technology which is confirmed visually using microscopy.Studies have shown the effect on the indications unevenness of the method of obtaining and the apparent density of the material. It is shown that the most uneven elastic properties and structure belong to sheets of polyolefin foam obtained by chemical cross-linking technology (the unevenness of Δ was 6.5 %). Among the physically cross-linked sheets of polyolefin foam the most uniform in structure and elastic properties are samples made of ethylene vinyl acetate with Δ = 3.8 %, as well as sheets with a high foaming rate (Δ = 3.9 %). The unevenness of structure of the studied sheets of polyolefin foams was confirmed by optical microscopy of sections in two mutually perpendicular directions.

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Sound absorption coefficient measurement by extracting the first reflected wave in a short tube

Wei

Gao

et al. 2020

Applied Acoustics

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Modified two-thickness method for measurement of the acoustic properties of porous materials

Cited by 7 publications

References 12 publications

Study on Sound Absorption Properties of Polyvinyl Chloride (PVC) Film Multicavity Structure Materials

Study on Sound Absorption Properties of Polyvinyl Chloride (PVC) Film Multicavity Structure Materials

Evaluation of Nonuniformity of Elastic Properties of Sheets Made from Closed-Сell Polyolefin Foams by Acoustic Method

Sound absorption coefficient measurement by extracting the first reflected wave in a short tube

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