Ultrasonic 3-D Reconstruction of Inclusions in Solids Using the Inverse Born Algorithm

摘要

An extensive study of the determination of geometric parameters (size, shape, and orientation) of included flaws using the one-dimensional inverse Born approximation. Investigation of the degradation of the 1-D Born inversion algorithm due to resonances and scattering showed that the degradation was not serious provided adequate frequency bandwidth was available. For inclusions in realistic structural materials, one would probably not expect high degrees of geometric symmetry in flaw shape and vast mismatch of impedance between the flaw and host material, strong and sharp characteristic resonances are therefore considered less likely. In the course of developing a reconstruction scheme in terms of an equivalent ellipsoid, the general case of an arbitrarily oriented ellipsoidal flaw was considered and the tangent plane distance, the tangent point distance and the transformation between them analyzed. The method developed was performed quite well in determining the size, shape, and orientation of ellipsoid-like flaws. The reconstruction technique was demonstrated for an inclusion in the bulk, for a void in metal and for an inclusion near a fluid-solid interface. (ERA citation 08:054533)