A GLOBAL SYSTEM-IDENTIFICATION APPROACH FOR THE ACCURATE PARAMETRIC MODELING OF ULTRASONIC REFLECTION AND TRANSMISSION EXPERIMENTS

This paper presents a global system identification approach for the pa rametric modeling of both reflection and transmission experiments perf ormed on a linear homogeneous visco-elastic material at normal inciden ce. It is shown that this global approach leads to improved estimates of the parameters occuring in the analytical model for the reflection and transmission coefficients of a visco-elastic plate immersed in wat er. The plane wave propagation model takes into account the absorption and dispersion in the material as well as an analytic diffraction cor rection for the beam spread. The proposed inverse procedure is based o n a maximum likelihood estimator.