A Technique for Determining Flaw Characteristics from Ultrasonic Scattering Amplitudes

We report an approximate technique for determining the characteristics of flaws in elastic media from a knowledge of their ultrasonic scattering amplitudes. The technique is rigorously valid in the weak scattering limit. Good results have been obtained for strongly scattering flaws. In particular, we tested the technique for a 2-1 oblate spheroidal void in Ti, and for various strongly scattering spherical defects. For these.tests the technique yields good results for the volume of the flaws. In the case of the oblate spheroid, satisfactory results were obtained for the calculated ratio of major to minor axis, indicating that the technique is sensitive to the shape of the flaw