ABSTRACT
The present study verifies the applicability of vibration-based Structural Health Monitoring (SHM) to identify debonding in bi-clamped metal-composite bonded joints, which can be applied in aeronautical structures. The method compares the Frequency Response Functions (FRFs) of the case studies with and without debonding damage. This analysis is done mainly through metrics of damage detection based on a comparison between the magnitude and phase angles of FRFs. The same metrics were also used after the application of a data filtering process. The specimens were manufactured from carbon-fiber-reinforced polymers and titanium and were joined by epoxy resin. Half of the specimens have a piezoelectric transducer (PZT) attached to the titanium adherent. The debonding damage was simulated for the damaged specimens by having 50% of the overlap area covered by a layer of Teflon. Three case studies have been reported: first, it verifies the influence of the PZT on FRFs; second, it evaluates the influence of the debonding damage by using accelerometers, and third, it performs the damage detection analysis by using the electrical responses of the PZT. Numerical and experimental analyses are compared, evaluating limitations and potentialities of the computational models. The results support the applicability of the metrics for damage quantification.
Acknowledgements
The authors would like to thank the São Paulo Research Foundation – FAPESP, as well as the National Council for Scientific and Technological Development (CNPq process number: 428591/2016-7 and 310656/2018-4). Besides, this study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior – Brasil (CAPES) – Finance Code 001.