Reference-free Damage Localization in Plate-like Structures Based on Multimode Separation
Zhang, M.
;
Ramos, H.
;
Ribeiro, A. L.
Reference-free Damage Localization in Plate-like Structures Based on Multimode Separation, Proc IEEE & FENDT IEEE Far East NonDestructive Testing FENDT, Zhongshan, China, Vol. , pp. - , June, 2024.
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Abstract
The effectiveness of Lamb waves based structural health monitoring (SHM) systems for monitoring the plate like structures has been previously established. Piezoelectric transducers (PZTs) are commonly chosen for their capability as both actuators and sensors, and for their ability to integrate within the structures. However, challenges arise due to the multimode nature of Lamb waves and the necessity for a reference signal to accurately identify the damage. To address these challenges, a reference-free damage localization method for plate-like structures that employs a multimode separation strategy was proposed in this paper. First, a multimode separation method that utilizes two PZTs positioned at the same planar coordinates was developed. Delay time and scaling factor were introduced to reduce errors caused by misalignment and inconsistent responses of PZTs. Then the interaction between Lamb waves and the discontinuity of the plate was explored. Considering the mode conversion resulting from defect and the employed mode separation strategy, a reference-free probabilistic localization imaging method was developed. The challenges, solutions and mathematical model of this method are discussed in detail. Finally, an experimental investigation using an aluminum plate was conducted to validate the proposed method. The results indicate that the proposed method yields accurate and reliable outcomes.