Transducer Placement Option of Lamb Wave SHM System for Hotspot Damage Monitoring

• Published in: Aerospace Vol. 5; no. 2; p. 39
• Main Authors: Ewald, Vincentius, Groves, Roger M., Benedictus, Rinze
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.06.2018
• Subjects: additive color model; Aircraft; Aircraft detection; Aircraft structures; Airframes; Algorithms; Aluminum; Centroids; Computer vision; Crack propagation; Damage detection; Damage tolerance; Fatigue cracks; Fatigue failure; Finite element method; finite element modelling; Fracture mechanics; Fuselages; hotspot damage; Image analysis; image processing; Lamb wave; Lamb waves; Optimization; Performance assessment; Placement; Position measurement; Position sensing; Propagation; sensor placement option; Sensors; Simulation; Structural health monitoring; Structural Health Monitoring (SHM); Wave propagation
• ISSN: 2226-4310; 2226-4310
• DOI: 10.3390/aerospace5020039

In this paper, we investigated transducer placement strategies for detecting cracks in primary aircraft structures using ultrasonic Structural Health Monitoring (SHM). The approach developed is for an expected damage location based on fracture mechanics, for example fatigue crack growth in a high stress location. To assess the performance of the developed approach, finite-element (FE) modelling of a damage-tolerant aluminum fuselage has been performed by introducing an artificial crack at a rivet hole into the structural FE model and assessing its influence on the Lamb wave propagation, compared to a baseline measurement simulation. The efficient practical sensor position was determined from the largest change in area that is covered by reflected and missing wave scatter using an additive color model. Blob detection algorithms were employed to determine the boundaries of this area and to calculate the blob centroid. To demonstrate that the technique can be generalized, the results from different crack lengths and from tilted crack are also presented.