Effect of the three-dimensional microstructure on the sound absorption of foams: A parametric study

Copyright 2017 Acoustical Society of America. This article may be downloaded for personal use only.Any other use requires prior permission of the author and the Acoustical Society of America.The following article appeared in the Journal of the Acoustical Society of America (JASA) and may be found at http://dx.doi.org/10.1121/1.4989373.International audienceThe purpose of this work is to systematically study the effect of the throat and the pore sizes on the sound absorbing properties of open-cell foams. The three-dimensional idealized unit cell used in this work enables to mimic the acoustical macro-behavior of a large class of cellular solid foams. This study is carried out for a normal incidence and also for a diffuse field excitation, with a relatively large range of sample thicknesses. The transport and sound absorbing properties are numerically studied as a function of the throat size, the pore size, and the sample thickness. The resulting diagrams show the ranges of the specific throat sizes and pore sizes where the sound absorption grading is maximized due to the pore morphology as a function of the sample thickness, and how it correlates with the corresponding transport parameters. These charts demonstrate, together with typical examples, how the morphological characteristics of foam could be modified in order to increase the visco-thermal dissipation effects