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Article
Experimental estimation of the transmission loss contributions of a sound package placed in a double wall structure
Applied Acoustics (2011)
  • Olivier Doutres, Ph.D.
  • Noureddine Atalla
Abstract
The objective of this paper is to propose a practical impedance tube method to optimize the sound transmission loss of double wall structure by concentrating on the sound package placed inside the structure. In a previous work, the authors derived an expression that breakdown the transmission loss of a double wall structure containing a sound absorbing blanket separated from the panels by air layers in terms of three main contributions; (i) sound transmission loss of the panels, (ii) sound transmission loss of the blanket and (iii) sound absorption due to multiple reflections inside the cavity. The sound transmission loss contributions of the blanket can thus be estimated from three acoustic measurements using impedance tube techniques: two reflection coefficients at the front face and the rear face of the blanket placed in specific positions characteristic of its position inside the double wall structure and its sound transmission coefficient. The method is first validated in the case of a double wall structure filled with a 2 inch foam material. Next, it is applied to investigate (i) the effect of frame compression of a 2 inch fibre glass in an aeronautic-type double wall structure and (ii) the effect of double porosity with or without porous inclusions in a building-type double wall structure. Copyright (2011) Applied Acoustics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the Elsevier Company.
Keywords
  • double wall,
  • porous materials,
  • transmission loss,
  • impedance tube,
  • double porosity,
  • frame compression
Publication Date
Winter 2011
Publisher Statement
Copyright (2010) Applied Acoustics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the Elsevier Company.
Citation Information
Olivier Doutres and Noureddine Atalla. "Experimental estimation of the transmission loss contributions of a sound package placed in a double wall structure" Applied Acoustics Vol. 72 Iss. 6 (2011)
Available at: http://works.bepress.com/olivier_doutres/25/