Matrix techniques for Lamb-wave damage imaging in metal plates

The implementation of efficient maintenance strategies of thin-walled structural components require reliable damage detection and localization techniques. In particular, guided ultrasonic waves technology represent an auspicious approach when implemented in a structural health monitoring system. The method is usually based on distributed sensing with piezoelectric elements that act in turn as ultrasound transmitter and receiver. This work aims at a unifying framework for damage localization considering algorithms from different scientific disciplines, e.g. originated from radar and geophysics. Here, we systematically express those algorithms in matrix form and compare the respective damage localization performance with experimental measurements considering an isotropic specimen with a single and also multiple simultaneous defects. In addition, we evaluate the algorithms' point spread function and propose performance metrics to quantitatively compare the imaging success.