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Effect of the microstructure closed pore content on the acoustic behavior of polyurethane foams
Journal of Applied Physics (2011)
  • Olivier Doutres, Ph.D.
  • Noureddine Atalla
  • Kevin Dong
The present paper proposes to investigate the links between the microstructure of polyurethane foams and their sound absorbing efficiency, and more specifically the effect of membranes closing the cells. This study is based on the complete characterization of 15 polyurethane foam with various cell sizes and reticulation rates (i.e., open pore content): (i) characterization of the microstructure properties (cell size Cs, strut thickness t, reticulation rate Rw…) from SEM pictures, (ii) characterization of nonacoustic parameters (porosity, airflow resistivity, tortuosity…) from direct and indirect methods. Existing analytical links between microstructure properties and nonacoustic parameters are first applied to fully reticulated materials. Then, they are improved empirically to account for the presence of the closed pore content. The proposed expressions associated to the Johnson-Champoux-Allard porous model allow a good estimation of the sound absorbing behavior of all polyurethane foams, fully reticulated or not. This paper also demonstrates the important effect of the presence of cell membranes: increase of the airflow resistivity, tortuosity, and the ratio between the thermal and viscous characteristic lengths while decreasing these two characteristic lengths. Thus, the sound absorption efficiency at low frequencies is improved but can be worsened in some higher frequency bands.
Publication Date
Summer September 1, 2011
Publisher Statement
Copyright (2011) American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in the Journal of Applied Physics and may be found at
Citation Information
Olivier Doutres, Noureddine Atalla and Kevin Dong. "Effect of the microstructure closed pore content on the acoustic behavior of polyurethane foams" Journal of Applied Physics Vol. 110 Iss. 6 (2011)
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