Sampath, S., Tham, Z. W., Zhang, Z., Chen, Y. F., Cheong, A. K.H., Chew, L. T., Seng, D. H.L., & Zhang, L. (2024). Non-contact imaging of microcracks in metallic coatings using laser excited acoustic shearography. Measurement, 116609. https://doi.org/10.1016/j.measurement.2024.116609
Abstract:
Metallic coatings are extensively used in various industries to protect substrate structures and restore worn or corroded parts. Laser ultrasonics is particularly attractive for inspecting these coatings due to its non-contact ultrasonic imaging capabilities and suitability for in-situ implementation. However, the point measurement nature of laser ultrasonics makes scanning large areas time-consuming. This paper presents a non-contact laser-excited acoustic shearography method for the rapid full-field imaging of microcracks in cold-sprayed aluminum coatings. The system employs a pulsed laser source to generate acoustic waves and a shearography camera to capture wave-defect interactions. Finite element simulations were conducted to explore the relationship between laser energy and the intensity of ultrasonic waves in substrates with coatings of varying microcrack widths. Four-point bending tests were performed to induce microcracks in the coatings. Results demonstrate that the proposed method effectively detects and quantifies microcrack size, providing a fast, full-field defect imaging solution for large structures.
License type:
Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0)
Funding Info:
This research / project is supported by the National Research Foundation, Singapore, and the Agency for Science, Technology and Research (A*STAR) - LCER Phase 2 Programme HETFI Directed Hydrogen Programme
Grant Reference no. : U2307D4002