| Several problems pertaining to the ultrasonic tomographic imaging of solid media are addressed in this thesis.;Experiments were also undertaken to study thermally induced microfracturing in granite rocks. These experiments showed that acoustical imaging techniques were useful to identify damage regions in the rock. It was found that the microfractures tended to coalesce into macroscopic fracture planes, which were successfully located.;Finally, a set of experiments was performed to examine the potential use of tomographic imaging using Rayleigh and Lamb waves, for non-destructive evaluation purposes. These experiments successfully imaged a variety of structures in metallic sheets and surfaces. In addition, damage zones in composite materials were identified. Immersion techniques as well as several forms of laser based non-contact techniques were studied.;Developments to tomographic imaging algorithms were made to deal with arbitrary data collection geometries, the phenomenon of raybending, and materials that display a velocity anisotropy. The updated algorithms were tested on a wide range of simulated and experimental data sets. These experimental data sets were acquired with a newly developed automatic scanning system. |
