Research on a defect detection method on carbon composite laminates based on digital shearography

Abstract

Subject of study. Carbon composite laminates are one of the major aviation structural materials. Owing to its merits of being non-contact, self-coherent, non-destructive, and full field, digital shearing speckle pattern interferometry (DSSPI) has the potential to be effective in the detection of defects on carbon composites with various surface shapes, especially the close-type defect on composite laminates. Method. In this paper, a DSSPI system containing both simulation and experiment, used for the measurement of carbon composite laminates with different curvature radii, is established. Main results. Based on our proposed criterion to evaluate whether the defects can be judged or not, the experiment loading parameters are applied, and the detection abilities under variable loading parameters are predicted. The effectiveness of the experiment system is verified through comparison with the X-ray and the ultrasound techniques. The simulation results are consistent with the experiments, showing its effectiveness. Practical significance. The work in this paper can provide reliable guidance to the loading parameters and predict the detection performance in a real DSSPI experiment system.