On the development of a virtual test bench to assess sound absorption of materials in an alpha chamber

Abstract A description is given of a virtual test-bench (VTB) designed by engineering center of Peter the Great St. Petersburg Polytechnic University to calculate a sound absorption coefficient of various materials. Developed VTB differs from known programs in that it allows a sound absorption coefficient of various materials to be determined with minimum involvement of an engineer. This VTB differs from other programs also by using infinite elements jointly with finite elements, which increases adequacy of the discrete model being used, and also the configuration of the boundary of an alpha chamber being used. The known programs use various phenomenological mathematical models of porous materials such as Johnson-Champoux-Allard (JCA) model. The VTB is based on fundamental mathematical models and statistical energy analysis (SEA) that allow describing adequately the established or transitional processes of sound absorption and reflection by a porous material the properties of which are not homogenized. The value of this VTB, which is created on the basis of a VA One software complex supplemented by a set of files of boundary conditions, files of solvers’ settings, secondary finite element (FE) models, is that VTB allows standardized calculations to be performed to determine the sound absorption coefficient of a material with minimum involvement of an engineer and the obtained result to be submitted for detailed processing. Developed virtual test-bench enables determination of a sound absorption coefficient for various materials within the entire finite frequency range. The result of the calculation is displayed as a graph of dependency of the material sound absorption coefficient on frequency.

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Acoustic Panels Made of Paper Sludge and Clay Composites

Sustainability ◽

10.3390/su13020637 ◽

2021 ◽

Vol 13 (2) ◽

pp. 637

Author(s):

Tomas Astrauskas ◽

Tomas Januševičius ◽

Raimondas Grubliauskas

Keyword(s):

Absorption Coefficient ◽

Sound Absorption ◽

Composite Panel ◽

Sound Absorption Coefficient ◽

Core Material ◽

Paper Sludge ◽

Frequency Range ◽

Absorption Properties ◽

Air Gaps ◽

The Core

Studies on recycled materials emerged during recent years. This paper investigates samples’ sound absorption properties for panels fabricated of a mixture of paper sludge (PS) and clay mixture. PS was the core material. The sound absorption was measured. We also consider the influence of an air gap between panels and rigid backing. Different air gaps (50, 100, 150, 200 mm) simulate existing acoustic panel systems. Finally, the PS and clay composite panel sound absorption coefficients are compared to those for a typical commercial absorptive ceiling panel. The average sound absorption coefficient of PS-clay composite panels (αavg. in the frequency range from 250 to 1600 Hz) was up to 0.55. The resulting average sound absorption coefficient of panels made of recycled (but unfinished) materials is even somewhat higher than for the finished commercial (finished) acoustic panel (αavg. = 0.51).

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Air permeability and sound absorption coefficient changes from ultrasonic treatment in a cross section of Malas (Homalium foetidum)

Journal of Wood Science ◽

10.1186/s10086-020-01940-w ◽

2021 ◽

Vol 67 (1) ◽

Author(s):

Chun-Won Kang ◽

Eun-Suk Jang ◽

Nam-Ho Lee ◽

Sang-Sik Jang ◽

Min Lee

Keyword(s):

Absorption Coefficient ◽

Ultrasonic Treatment ◽

Sound Absorption ◽

Gas Permeability ◽

Treated Wood ◽

Untreated Wood ◽

Sound Absorption Coefficient ◽

Permeability Constant ◽

Average Value ◽

Permeability Increase

AbstractWe investigated the effect of ultrasonic treatment on Malas (Homalium foetidum) gas permeability and sound absorption coefficient using the transfer function method. Results showed a longitudinal average Darcy permeability constant of 2.02 (standard deviation SD 0.72) for untreated wood and 6.15 (SD 3.07) for ultrasound-treated wood, a permeability increase of 3.04 times. We also determined the average sound absorption coefficients in the range of 50 to 6.4 kHz and NRC (noise reduction coefficient: average value of sound absorption coefficient value at 250, 500, 1000, and 2000 Hz) of untreated Malas. Those values were 0.23 (SD 0.02) and 0.13 (SD 0.01), respectively, while those of ultrasonic-treated Malas were 0.28 (SD 0.02) and 0.14 (SD 0.02), a 19.74% increase in average sound absorption coefficient.

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Research of Possibilities of Using the Recycled Materials Based on Rubber and Textiles Combined with Vermiculite Material in the Area of Noise Reduction

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1001.171 ◽

2014 ◽

Vol 1001 ◽

pp. 171-176 ◽

Cited By ~ 4

Author(s):

Pavol Liptai ◽

Marek Moravec ◽

Miroslav Badida

Keyword(s):

Absorption Coefficient ◽

Standing Wave ◽

Sound Pressure Level ◽

Sound Absorption ◽

Sound Pressure ◽

Sound Level ◽

Pressure Level ◽

Sound Absorption Coefficient ◽

Physical Parameters ◽

Materials Research

This paper describes possibilities in the use of recycled rubber granules and textile materials combined with vermiculite panel. The aim of the research is the application of materials that will be absorbing or reflecting sound energy. This objective is based on fundamental physical principles of materials research and acoustics. Method of measurement of sound absorption coefficient is based on the principle of standing wave in the impedance tube. With a sound level meter is measured maximum and minimum sound pressure level of standing wave. From the maximum and minimum sound pressure level of standing wave is calculated sound absorption coefficient αn, which can take values from 0 to 1. Determination of the sound absorption coefficient has been set in 1/3 octave band and in the frequency range from 50 Hz to 2000 Hz. In conclusion are proposed possibilities of application of these materials in terms of their mechanical and physical parameters.

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Using the acoustic method for measuring the sound absorption coefficient to predict the durability (heat resistance) of heat-resistant concretes

NOVYE OGNEUPORY (NEW REFRACTORIES) ◽

10.17073/1683-4518-2020-12-43-48 ◽

2021 ◽

pp. 43-48

Author(s):

R. Stonys ◽

A. Jagniatinskis ◽

J. Malaiškienė ◽

J. Škamat ◽

V. Antonovič ◽

...

Keyword(s):

Absorption Coefficient ◽

Heat Resistance ◽

Sound Absorption ◽

Acoustic Method ◽

Sound Absorption Coefficient ◽

Heat Resistant

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Performance Testing for Sound Absorption Coefficient by Using Impedance Tube

Research Journal of Applied Sciences Engineering and Technology ◽

10.19026/rjaset.11.1706 ◽

2015 ◽

Vol 11 (2) ◽

pp. 185-189 ◽

Cited By ~ 4

Author(s):

J. Niresh ◽

S. Neelakrishna ◽

S. Subharan ◽

R. Prabhakaran

Keyword(s):

Absorption Coefficient ◽

Sound Absorption ◽

Performance Testing ◽

Sound Absorption Coefficient ◽

Impedance Tube

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Study on the sound absorption behavior of multi-component polyester nonwovens: experimental and numerical methods

Textile Research Journal ◽

10.1177/0040517518811940 ◽

2018 ◽

Vol 89 (16) ◽

pp. 3342-3361 ◽

Cited By ~ 7

Author(s):

Tao Yang ◽

Ferina Saati ◽

Kirill V Horoshenkov ◽

Xiaoman Xiong ◽

Kai Yang ◽

...

Keyword(s):

Numerical Methods ◽

Absorption Coefficient ◽

Empirical Model ◽

Surface Impedance ◽

Sound Absorption ◽

Low Frequency ◽

Accurate Method ◽

Small Error ◽

Sound Absorption Coefficient ◽

Acoustical Properties

This study presents an investigation of the acoustical properties of multi-component polyester nonwovens with experimental and numerical methods. Fifteen types of nonwoven samples made with staple, hollow and bi-component polyester fibers were chosen to carry out this study. The AFD300 AcoustiFlow device was employed to measure airflow resistivity. Several models were grouped in theoretical and empirical model categories and used to predict the airflow resistivity. A simple empirical model based on fiber diameter and fabric bulk density was obtained through the power-fitting method. The difference between measured and predicted airflow resistivity was analyzed. The surface impedance and sound absorption coefficient were determined by using a 45 mm Materiacustica impedance tube. Some widely used impedance models were used to predict the acoustical properties. A comparison between measured and predicted values was carried out to determine the most accurate model for multi-component polyester nonwovens. The results show that one of the Tarnow model provides the closest prediction to the measured value, with an error of 12%. The proposed power-fitted empirical model exhibits a very small error of 6.8%. It is shown that the Delany–Bazley and Miki models can accurately predict surface impedance of multi-component polyester nonwovens, but the Komatsu model is less accurate, especially at the low-frequency range. The results indicate that the Miki model is the most accurate method to predict the sound absorption coefficient, with a mean error of 8.39%.

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