A semi-empirical model to predict the acoustic behaviour of fully and partially reticulated polyurethane foams based on microstructure properties

Olivier Doutres (1) , Noureddine Atalla (1)

1 GAUS - Groupe d'Acoustique de l'Université de Sherbrooke

This work investigates the links between the microstructure of polyurethane foams and their sound absorbing efficiency, and more specifically the effect of membranes closing the cells. The study is based on the complete characterization of 15 isotropic polyurethane foams with various cell sizes and reticulation rates (i.e. open pore content): (i) characterization of the microstructure properties from SEM pictures, (ii) characterization of non-acoustic parameters from direct and indirect methods. Existing analytical links between microstructure properties and non-acoustic 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 for a good estimation of the sound absorbing behaviour of all tested polyurethane foams, fully reticulated or not. It is shown that the reticulation rate is an important parameter having a large influence on the acoustic behaviour, i.e. it dominates the cell size influence. The semi-empirical model is applied and validated using 4 new PU foams, not used in the first characterization set. Finally, its practical use is illustrated by optimizing acoustical materials with graded properties.

Mots clés: polyurethane foam; microstructure; reticulation; acoustic properties

Domaines: Acoustique [physics.class-ph]

Olivier Doutres, Noureddine Atalla. A semi-empirical model to predict the acoustic behaviour of fully and partially reticulated polyurethane foams based on microstructure properties. Acoustics 2012, Apr 2012, Nantes, France. ⟨hal-00810670⟩