Study of plane periodic multilayered viscoelastic media: Experiment and simulation

Phononic crystals or periodic media are widely studied because of their very interesting properties such as exhibiting absolute or local band gaps in their dispersion curves. This preliminary work deals with plane multilayers composed of 1, 2 and 3 elementary periods. The aim of this study is to compare experiments and modeling results where the plates and periods are supposed perfectly bonded. The studied period is composed of aluminum and polyethylene plates. Simulations are based on the stiffness matrix method [1]. When attenuation is considered in polyethylene, the reflection coefficients are different depending on the insonification side. Attenuation of the whole multilayer could be deduced by comparison of simulation and experimental data. Pulse-echo measurements have been performed to obtain the longitudinal attenuation in the polyethylene layer.