ةtude par microscopie acoustique de lʹeffet dʹatténuation transversale et longitudinale sur les modes de propagation dans les structures monocouches et multicouches

This Note considers the study by modelling of the effect of transversal and longitudinal attenuation on the propagation modes in certain monolayers (layer/substrate): Cr/Fe, Al/Si and in multilayer structures: Al/epoxy/Al. The study is based on modelling the acoustic signal detected by the reflection acoustic microscope during the investigation of a coated material. The use of the simulated signal allows us to know the variation of the reflection coefficient as a function of the excitation acoustic wave incidence angle. Moreover, and for monolayer materials, we have also determined the variations of the coefficient as a function of the coefficient of attenuation. ese materials the calculations have been made over a large frequency range (50 MHz to 3.5 GHz) and for coating thicknesses from 0.5 μm to 150 μm. In the case of multilayer structures, we have determined the variations in speed of the different propagation modes as functions of frequency and the attenuation coefficient. To cite this article: T. Tahraoui et al., C. R. Physique 10 (2009).