Ultrasonic guided-wave testing can greatly benefit from (1) an ability to provide quantitative information on the damage that is being detected, and (2) an ability to select the best mode-frequency combination for maximum sensitivity to a given type of damage. Achieving these capabilities in complex structures (e.g. nonprismatic structures such as a stiffened panel in aerospace fuselages) is a nontrivial task. This paper will discuss an improved Global-Local (GL) method where the geometrical “local” discontinuity (e.g. the stiffener) is modelled by traditional FE discretization and the rest of the structure (“global” part) is modelled by Semi-Analytical Finite Element (SAFE) cross-sectional discretization. The boundaries of the “local” domain and the “global” domain are then matched in terms of wave displacement and stresses. GL models have been proposed in the past using theoretical (Lamb) wave solutions that only apply to isotropic plates. The authors have also previously studied GL methods using the SAFE approach for application to multi-layered anisotropic plates for which theoretical solutions are either not existent or hard to obtain. This work will extend recent research on these methods by optimizing the Matlab routine that is used to run the GL code, correcting some formulation errors that were present in the previous edition, and studying the specific case of a composite panel stiffened with cocured stringers that is representative of modern commercial aircraft construction (e.g. Boeing 787). The newlyformulated GL method will be shown to provide excellent results that can help designing a guided-wave test on these aircraft components for optimum detection of relevant damage that can be induced by impacts (including skin delaminations, stringer heel cracks, and stringer to skin disbonds). Other applications of the GL methods beyond stiffened aircraft panels will be discussed.
Antonino Spada, Margherita Capriotti, Ranting Cui, and Francesco Lanza di Scalea, "Improved global-local model to predict guided-wave scattering patterns from discontinuities in complex parts," Proc. SPIE 10972, Health Monitoring of Structural and Biological Systems XIII, 109720M (Presented at SPIE Smart Structures + Nondestructive Evaluation: March 05, 2019; Published: 1 April 2019); https://doi.org/10.1117/12.2514082.
Conference Presentations are recordings of oral presentations given at SPIE conferences and published as part of the proceedings. They include the speaker's narration with video of the slides and animations. Most include full-text papers. Interactive, searchable transcripts and closed captioning are now available for most presentations.
Search our growing collection of more than 18,000 conference presentations, including many plenaries and keynotes.