An empirical modelling of porous sound absorbing materials made of recycled foam

Polyurethane foam waste is one of the residues of the manufacturing processes in textile industry, the disposal of which is becoming a severe environmental problem. In this paper the sound absorption properties of different materials developed from ground polyurethane foam waste are studied. Because these recycled materials exhibit good sound absorbing properties they are viable alternatives to conventional materials for practical applications. Experimental measures have been carried out to determine the characteristic wave impedance and propagation constant of these materials. Modelling of the acoustic behaviour has been done using the Dunn and Davern model and Voronina model. The first model presents deviations in the results so the experimental results have been used to report corrections to the empirical model. The Voronina model has been applied to verify that it serves to model the behaviour of these kinds of recycled materials. Both models converge and present acceptable results.