Defect detection and imaging using focused ultrasonic guided waves

The use of numerical and phased focusing to perform guided wave inspection of plates and pipes has not been widely used. Such inspection technique represents an interesting solution for defect detection and localization. In addition, imaging of ultrasonic guided waves inspection using color coded B-Scans is also considered a highly valuable tool for data interpretation. The present paper presents an experimental study for the implementation of focal law algorithms applied to the inspection of plate structures using ultrasonic Lamb waves generated by the angle beam wedge method. The wedge properties and the considerations for the image representation are outlined in this work. A comparison between spike and tone burst excitation is also performed, demonstrating the feasibility of the Lamb wave inspection technique with both type of excitations.