Multihelical Lamb Wave Imaging for Pipe-Like Structures Based on a Probabilistic Reconstruction Approach

The special form of pipe-like structure provides the helical route for ultrasonic guided wave. Considering pipe as a flattened plate but with periodical replications, wave becomes intuitional and corresponding imaging algorithm can be constructed. This work proposes multihelical Lamb method by utilizing multiple arrival wavepackets which are denoted different orders. signal model is presented constant group velocity point illustrated. probabilistic reconstruction combined separation fusion routes. To verify proposed scheme, finite element simulations experiments conducted. cases single-defect simulation two-defect indicate successful robust implementation algorithm. test on actual damage also investigated to show its capability in an irregular defect. comparison results from only first demonstrates advantage imaging, including better resolution higher localization accuracy.