NUMERICAL-METHOD TO RECOVER THE ELASTIC-CONSTANTS FROM ULTRASOUND GROUP VELOCITIES

This paper proposes a numerical method for the identification of elast ic constants. The method is based on a least-squares fit from the ultr asonic wave group velocities, as a function of the propagation directi on in the principal planes. This algorithm is deduced from considerati ons on the Cagniard-de Hoop contour, associated with the fact that the wave arrival times correspond to discontinuities on the waveform. Two polynomials, in terms of group velocities, are then obtained. These t wo polynomials are linked by the phase slowness component on the surfa ce. The method to recover the elastic constants is applied to simulate d group velocities corresponding to a real composite material.