Analysis of polyurethane nanocomposite sound absorbers based on Johnson-Champoux-Allard model

Document Type : Research Paper


Department of Sound, Faculty of Engineering, IRIB University, P.O. Box 19395-1746, Tehran, I.R. Iran


It is interesting to predict the porous materials' noise-control impact at the design stage to fabricate a desirable sound-absorbing structure that performs well for a wide frequency range, especially in low frequencies. For this aim, validation of the Johnson-Champoux-Allard (JCA) model to estimate the sound-absorbing performance of the polyurethane (PU) nanocomposite foams has been examined. To follow the procedure described by the JCA model, first, the effect of adding the different loading fractions of carboxylated CNT as filler to the PU matrix on its microstructural parameters such as tortuosity and airflow resistivity has been discussed in detail. Second, the characteristic wave impedance and propagation constant as the main values used to predict the acoustical performance of the material obtained. Validation of the proposed approach was examined for PU/CNT nanocomposite foams, experimentally. The results show that the JCA model can predict the overall sound-absorbing behavior of the PU/CNT nanocomposite foams by adding the different CNT content, in good accordance with the experimental measurements. However, in estimating the average sound absorption coefficient of the samples in the frequency range of 20 to 6400 Hz, there is an error of about 22%, and in the high-frequency range, the error decreases to about 12%.