For several decades, porous materials have been widely used for noise
and vibration control purposes in building and transportation
industries.
Numerous works on the subject have been published (even more has not
been yet) and it appears that there is a lack of conciseness for this
volume of information since the book by Jean-Francois Allard:
Propagation of sound in porous media; modelling sound absorbing
materials published in 1993 is out of print (cf. [All93]).
The aim of this site is to gather information and experience feedbacks
about the published works in the field of acoustical porous material:
models for the propagation of sound, parameter definitions and
characterization techniques, standards...
In few words, we wish APMR to become an living internet encyclopedia and an easy
way to find updated information about acoustical porous media.
To properly view these pages, you will need a recent Internet browser supporting MathML.
Mozilla users should read information about the fonts to install and Microsoft Internet Explorer users should consider installing MathPlayer plug-in.
JavaScript is also required to be enabled.
If you have MathML fonts and/or plug-in installed, you should be able
to read, below, the expression of the dynamic density of an acoustical
porous material given by Johnson et al. [JKD87]:
$
\widetilde{\rho}(\omega) =
\displaystyle{\frac{\alpha_{\infty}\rho_{0}}{\phi}}
\left[ 1 + \displaystyle{\frac{\sigma\phi}
{j\omega\rho_{0}\alpha_{\infty}}}
\displaystyle{\sqrt{ 1 + j\displaystyle{\frac{4\alpha_{\infty}^{2}\eta\rho_{0}\omega}
{\sigma^{2}\Lambda^{2}\phi^{2}}}
} \,\, \right]
$
The content of APMR is growing day after day. Below are the subjects discussed or planned to be discussed.
- Basics of Materials
- Basics of Acoustics
- Basics of Mechanics
- Propagation models
- Parameters of models
- Characterization of parameters
- Standards
References
[All93]
Allard, J.-F.,
Propagation of sound in porous media; modelling sound absorbing materials,
Elsevier, 1993.
[JKD87]
Johnson D. L., Koplik J. and Dashen R.,
Theory of dynamic permeability and tortuosity in fluid-saturated porous media,
J. Fluid Mech., 176, 1987, pp. 379-402
.
The