Proof-of-Concept Studies in Novel Guided Wave Methods for Metallic Structural Condition

摘要

Active sensing in structural health monitoring (SHM) refers to injecting (user-defined) energy into the system in order to actively probe its response to the induced dynamics as a means of detecting whether damage may be present in the system. A number of researchers have shown that active sensing with guided ultrasonic waves (GUWs) can be a powerful approach to take, as GUWs, when launched and detected in conjunction with macro-fiber composite (MFC) patches, can retain the wide area coverage capability of lower frequency (vibration) methods while significantly enhancing sensitivity to flaws (cracks, corrosion, etc.) because of the small interrogating wavelengths used. This project, led by PI Michael Todd and Co-PI Francesco Lanza di Scalea, considered several new concepts in guided GUWs: (1) optimized passive GUWs, (2) quantitative active GUWs, and (3) a generalized insonification (diffuse field) approach rooted in data-based modeling and pattern recognition. These concepts are tested on metallic test articles to detect a variety of defects, including impact damage, simulated cracks (notching), corrosion, and bolted joint preload loss.