Sadouki, Mustapha, Berbiche, Amine, Fellah, Mohamed, Fellah, Z.E.A, Depollier, Claude, Université des Sciences et de la Technologie Houari Boumediene = University of Sciences and Technology Houari Boumediene [Alger] (USTHB), Ondes et Imagerie (O&I), Laboratoire de Mécanique et d'Acoustique [Marseille] (LMA ), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Acoustique de l'Université du Mans (LAUM), Le Mans Université (UM)-Centre National de la Recherche Scientifique (CNRS), Université des Sciences et de la Technologie Houari Boumediene [Alger] (USTHB), Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)-École Centrale de Marseille (ECM), and Centre National de la Recherche Scientifique (CNRS)-Le Mans Université (UM)
International audience; An improved method is proposed for measuring porosity, tortuosity, viscous and thermal characteristic length of porous materials having a rigid frame via reflected ultrasonic waves at oblique incidence. The conventional ultrasonic approach can be used to determine all the parameters via transmitted waves [1] or using the rst and second reflected waves at normal incidence[2] (the ratio between the viscous and thermal characteristic lengths is xed as in classical acoustic methods [3,4]). The advantage of the proposed method is that the four parameters are determined simultaneously just using reflected experimental waves for a porous material saturated by air. In addition, no relationship is assumed between the two characteristic lengths. The inverse problem is solved based on the least-square numerical method using experimental refllected waves in time domain. Tests are performed using industrial plastic foams. Experimental and numerical validation results of this method are presented.Reference[1] ZEA Fellah, M Sadouki, M Fellah, F. G Mitri, E Ogam, C Depollier." Simultaneous determination of porosity, tortuosity, viscous and thermal characteristic lengths of rigid porous materials" J. Appl. Phys, 114, 204902 (2013); [2] Z. E. A. Fellah, M. Fellah, W. Lauriks, and C. Depollier, "Direct and inverse scattering of transient acoustic waves by a slab of rigid porous material" J. Acoust. Soc. Am. 113, 61-73 (2003). [3] C. Ayrault, A. Moussatov, B. Castagnede, and D. Lafarge, "Ultrasonic characterization of plastic foams via measurements with static pressure variations" Appl. Phys. Lett. 74, 3224-3226 (1999). [4] A. Moussatov, C. Ayrault, and B. Castagne`de, "ultrasonic method for estimation of tortuosity and characteristic length using a barometric chamber"Ultrasonics 39, 195-202 (2001).