ON THE NONINVASIVE DETERMINATION OF MATERIAL PARAMETERS FROM A KNOWLEDGE OF ELASTIC DISPLACEMENTS - THEORY AND NUMERICAL-SIMULATION

In this paper, we present a formulation and numerical simulation for t he noninvasive determination of the material parameter ratios (i.e., t he Lame parameters divided by density) of an isotropic, inhomogenous e lastic medium subject to time harmonic vibration. Given a knowledge of the displacements throughout the medium, a novel implementation of a variational formulation is used to determine the ratios lambda/rho and mu/rho. A theoretical formulation is presented and validated using nu merical data obtained from a finite element method. The results indica te that the method may be applied locally within an inhomogenous mediu m, and that the corresponding material parameters can be recovered to a high degree of accuracy. In addition, the method does not appear to be subject to the typical wavelength constraints of previous methods.