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Title

Sound absorption characteristics of aluminum foam with spherical cells

Author(s)

Li, Yunjie;  Wang, Xinfu;  Wang, Xingfu;  Ren, Yuelu;  Han, Fusheng;  Wen, Cuie

Abstract

Aluminum foams were fabricated by an infiltration process. The foams possess spherical cells with a fixed porosity of 65% and varied pore sizes which ranged from 1.3 to 1.9 mm. The spherical cells are interconnected by small pores or pore openings on the cell walls that cause the foams show a characteristic of open cell structures. The sound absorption coefficient of the aluminum foams was measured by a standing wave tube and calculated by a transfer function method. It is shown that the sound absorption coefficient increases with an increase in the number of pore openings in the unit area or with a decrease of the diameter of the pore openings in the range of 0.3 to 0.4 mm. If backed with an air cavity, the resonant absorption peaks in the sound absorption coefficient versus frequency curves will be shifted toward lower frequencies as the cavity depth is increased. The samples with the same pore opening size but different pore size show almost the same absorption behavior, especially in the low frequency range. The present results are in good agreement with some theoretical predictions based on the acoustic impedance measurements of metal foams with circular apertures and cylindrical cavities and the principle of electroacoustic analogy.

Publication type

Journal article

Research centre

Swinburne University of Technology. Faculty of Engineering and Industrial Sciences

Source

Journal of Applied Physics, Vol. 110, no. 11 (Dec 2011), article no. 113525

Publication year

2011

FOR Code(s)

01 Mathematical Sciences;  02 Physical Sciences;  09 Engineering

Keyword(s)

Acoustic impedance;  Acoustic wave absorption;  Acoustoelectric effects;  Aluminum foams;  Metal foams;  Pore openings;  Porosity;  Sound absorption;  Spherical cells;  Transfer function matrices

Publisher

American Institute of Physics

ISSN

0021-8979

Publisher URL

http://dx.doi.org/10.1063/1.3665216

Copyright

Copyright © 2011 American Institute of Physics. Published version of this paper reproduced here with the kind permission of the publisher.

Additional information

The authors acknowledge support from the National Basic Research Program of China (Grant No. 2011CB610300), the National Natural Science Foundation of China the Knowledge Innovation Program of the Chinese Academy of Sciences (Grant No. 50871107).

Full text

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