Sparse Array (Nonlinear) Guided Wave Imaging for Localization of Damage in Composites

Composite materials are subjected to an increasing importance in critical components commonly used for automotive, aerospace and other modern industrial sectors. Yet, these composites are quite susceptible to damages and defects which can be introduced during the manufacturing and/or operational life. Reconstruction Algorithm for the Probabilistic Inspection of Damage (RAPID) and Delay and Sum (DAS) are well-known guided wave imaging techniques capable to reveal the presence of damage in a sparse ultrasonic sensor network. In this study, several factors in RAPID are investigated to understand their influence on the quality of the reconstructed damage map for a composite laminate with an inter-ply defect. A critical comparison between RAPID and DAS is performed in terms of their accuracy and calculation cost. Finally, results are presented on a baseline-free probabilistic imaging modality by exploiting nonlinear wave/defect interactions.