A Modal Decomposition Imaging Algorithm for Ultrasonic Detection of Delamination Defects in Carbon Fiber Composite Plates Using Air-Coupled Lamb Wave

In this paper, a modal decomposition imaging (MDI) algorithm for detecting delamination defects in carbon fiber composite plates using air-coupled Lamb wave is proposed. Compared with the traditional time-domain imaging method, the proposed MDI algorithm contains the pretreatment of the echo data and the imaging calculation, which is more suitable for analyzing the nonlinear and non-stationary leakage Lamb wave signal. The instantaneous energy is constructed to be the index of the MDI algorithm, which is obtained by the pretreatment of the time-domain echo data carried by the pure A0 mode Lamb wave. The effectiveness of MDI algorithm proposed in this paper for realizing the delamination defects of carbon fiber composite plates can be verified by qualitative imaging and quantitative characterization comparing with the defect probability imaging (DPI) algorithm. It will be suitable for in situ testing and large-area rapid scanning of aerospace composite plates in the future