Identification of shear wave parameters of viscoelastic solids by laboratory measurements of Stoneley-Scholte waves

Abstract

International audienceThis paper deals with the problem of viscoelastic solid characterization by acoustical means and in particular with the recovery of the shear wave parameters. It has been previously shown, in the Underwater Acoustics field, that the shear wave parameters of the sea floor could be recovered by using inverse techniques applied to propagation characteristics of interface waves such as Stoneley-Seholte waves, which can propagate in water/sedi ment configurations. The goal of the study presented in the paper is then to test models, commonly used for seabed identification, on media whose properties arc well-controlled by laboratory tank experiments, contrary to in situ bottoms. It is shown that the viscoelastic medium parameters can also be identified from the characteristics of interface waves, generated experimentally in laboratory on very attenuating synthetic materials. The paper presents results about the estimated shear wave parameters obtained from both numerical and experimental data by applying Brent's method on the characteristics of the interface waves. The observation and the discussion of differences between theoretical and experimental results are the goa] of the paper. The study presented here validates the forward model previously developed and it can be considered as a first step towards the direction of acoustic classification of sea bottoms