Outcome: An interdisciplinary group of researchers from Villanova University College of Engineering have developed analytical models that can predict the interaction of guided waves with plate edges shedding light into a complex wave propagation phenomenon. Understanding this interaction is critical to devise efficient and practical sensing systems for structural health monitoring (SHM) of critical structures.
Impact/Benefit: The analytical models that explain the wave reflection from the plate edges improves our understanding of higher order reflections (multipath) of Guided waves associated with the defect signatures. Such models will pave the way for a comprehensive wave propagation model in plates, and consequently enable exploitation of higher order reflections (multipath) in the detection, localization and classification of defects. Exploitation of multipath presents unparalleled opportunities in SHM of plates, such as the ability to detect damage near the plate edges, significant reduction of the number of sensors without compromising the performance, and more freedom to place sensors near the edges of plates. This advancement is poised to improve the efficiency of the SHM systems and make it more practical in field testing conditions.
Explanation: Guided waves have been increasingly used for structural health monitoring of critical structures (e.g., airplane panels, wind-turbine blades) due to the propensity of these waves to traverse large distances with fairly low attenuation and their high-sensitivity to defects. However, guided waves interact with not just defects but also the plate edges giving rise to higher order reflections, i.e., multipath. Such multipath has been considered traditionally as troublesome because it typically obscures the desired signals associated with defects and, thereby, complicates defect analysis. Unlike existing methods that avoid or mitigate such reflections, the devised advanced wave interaction model enables utilization of multipath for structural health monitoring of critical structures.
Experimental study of guided waves interacting with the plate edges: a) PZT sensor network placed on an aluminum plate for experimental verification of the analytical wave interaction model, b) Various propagation modes identified in the acquired data based on the devised analytical model.