Signal Processing and Imaging with Ultrasonic Guided Waves: Goals, Challenges and Recent Progress

Abstract Ultrasonic guided waves have the potential for both rapid inspection and in situ monitoring of plate-like structures, and effective signal processing and imaging algorithms are essential to achieve necessary performance. Although guided waves can propagate long distances and still remain sensitive to damage, their dispersive nature and sensitivity to varying environmental and operational conditions offer significant challenges. This paper addresses two guided wave applications that have recently been the subject of significant research. The first is acquisition and analysis of full or partial guided wavefield data such as can be obtained by either a scanning laser vibrometer or a scanned air-coupled transducer. This application is motivated by the need for a rapid alternative to traditional bulk wave inspections that does not require extensive teardown or liquid couplants. The second is in situ monitoring using a spatially distributed array of simple piezoelectric transducers. This application is motivated by the need for long term monitoring of critical structures to both lower maintenance costs and prevent catastrophic failures. Recent results are presented from current and past projects of the QUEST Laboratory at Georgia Tech.