Ultrasonic Lamb wave tomography of discontinuities in metallic plates

Tomography refers to the cross-sectional imaging of an object from either transmission or reflection of data collected by irradiating the object from many different directions. Recent efforts on the study of wave interaction between ultrasonic signals and defects have been focused on the characterization of the discontinuity geometry using ultrasonic guided waves. Lamb wave tomography has some advantages with respect to classical inspections based on real time analysis. However, ultrasonic tomography continues to be an unsolved problem. The main focus of this work is the implementation of an experimental set-up for the generation, data gathering and post-processing processes of guided waves by using broadband ultrasonic longitudinal contact transducers and Time Frequency Representation (TFR) of ultrasonic Lamb waves.