Aj. Romano et al., ON THE NONINVASIVE DETERMINATION OF MATERIAL PARAMETERS FROM A KNOWLEDGE OF ELASTIC DISPLACEMENTS - THEORY AND NUMERICAL-SIMULATION, IEEE transactions on ultrasonics, ferroelectrics, and frequency control, 45(3), 1998, pp. 751-759
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.