Archives of Acoustics, 46, 4, pp. 649–656, 2021
10.24425/aoa.2021.139641

Numerical Methodology to Obtain the Sound Absorption of Materials by Inserting the Acoustic Impedance

Cláudia Ohana BORGES MENDES
University of Brasília-UnB, College UnB Gama-FGA
Brazil

Maria Alzira DE ARAÚJO NUNES
University of Brasília-UnB, College UnB Gama-FGA
Brazil

Numerical models allow structural characteristics to be obtained by solving mathematical formulations. The sound absorption capacity of a material can be acquired by numerically simulating an impedance tube and using the method governed by ISO 10534-2. This study presents a procedure of obtaining sound pressure using two microphones and as outline condition, at one end of the tube, the impedance of fiber samples extracted from the pseudostem of banana plants. The numerical methodology was conducted in the ANSYS® Workbench software. The sound absorption coefficient was obtained in the MATLAB® software using as input data the sound pressure captured in the microphones and applying the mathematical formulations exposed in this study. For the validation of the numerical model, the results were compared with the sound absorption coefficients of the fiber sample collected from an experimental procedure and also with the results of a microperforated panel developed by Maa (1998). According to the results, the methodology presented in this study showed effective results, since the largest absolute and relative errors were 0.001 and 3.162%, respectively.
Keywords: impedance tube; ANSYSRO; finite element method; sound absorption
Full Text: PDF
Copyright © The Author(s). This is an open-access article distributed under the terms of the Creative Commons Attribution-ShareAlike 4.0 International (CC BY-SA 4.0).

References

ASTM E1050:2019, Standard test method for impedance and absorption of acoustical materials using a tube, two microphones and a digital frequency analysis system.

ASTM E354:2003, Acoustics – measurement of sound absorption in a reverberation room.

Bóden H., Abom M. (1986), Influence of erros on the two-microphone method for measuring acoustic properties in ducts, The Journal of the Acoustical Society of America, 79(2): 541–549, doi: 10.1121/1.393542.

Ming-hui G, Qing-quan H, Jin-man W, Hai-peng Y. (2010), The modeling and simulation analysis of wooden perforated panel absorption structure, Noise & Vibration Wordwide, 41(10): 72–75, doi: 10.1260%2F0957-4565.41.10.72.

Howard C.Q., Cazzolato B.S. (2014), Acoustic Analyses using MATLAB® and ANSYS®, Boca Raton: CRC Press, Taylor & Francis Group.

ISO 10534-1:1996, Acoustic – Determination of sound absorption coefficient and impedance in impedance tubes – Part 1: Method using standing wave ratio.

ISO 10534-2:1998, Acoustics – Determination of sound absorption coefficient and impedance in impedance tubes. Part 2: Transfer-function method.

ISO 354:2003, Measurement of sound absorption in a reverberant room.

Kinsler L.E., Frey A.R., Coppens A.B., Sanders J.V. (2000), Fundamentals of Acoustics, Hoboken: John Wiley & Sons, New York.

Lara L.T., Boaventura W.C., Pasqual A.M. (2016), Improving the estimated acoustic absorption curves in impedance tubes by using wavelet-based denoising methods [in Spanish], Congresso Iberoamericano de Acústica, Buenos Aires, Argentina, 22, 1-10.

Maa D.Y. (1998), Potential of microperforated panel absorber, The Journal of the Acoustical Society of America, 104(5): 2861–2866, doi: 10.1121/1.423870.

Rienstra S.W., Hirschberg A. (2014), An Introduction to Acoustics, Eindhoven University of Technology, Netherlands.

Silva G.C.C., Nunes M.A.A., Almeida Jr A.B., Lopes R.V. (2013), Acoustic design and construction of an impedance tube for experimental characterization of sound absorbed materials [In Portuguese: Projeto Acústico e Construção de um Tubo de Impedância para Caracterização Experimental de Materiais com Absorção Sonora], [In:] XVIII Congresso de Iniciação Científica da UnB, Brasília, Brazil.

Soriano H.L. (2009), Finite Elements – Formulation and Application in Static and Dynamic Structures [in Portuguese: Elementos Finitos – Formulação e Aplicação na Estática e Dinâmica das Estruturas], Rio de Janeiro: Editora Ciência Moderna Ltda.




DOI: 10.24425/aoa.2021.139641