Debonding detection of scarf-repaired composite laminates with laser ultrasonic Lamb waves

Abstract

Abstract In this article, the Lamb wave at low frequency range is chosen to detect the debonding of scarf surface at different depths. The structure of interest is made up of two carbon fiber reinforced laminates with a scarf angle of 5° bonded together by an adhesive film. A 3D finite element model is established to calculate the propagation of Lamb waves with an artificial defect. Based on the wave front of out-of-plane displacement at different timepoint, the debonding area is located when propagating waves convert mode or reduce phase velocity. For validation, experiments are also conducted with wave-visualization technique. Lamb waves are excited by laser ultrasonic system and received by an acoustic emission sensor. The results agree with the simulation ones, which verify that the laser ultrasonic Lamb waves are effective for debond detection on the inclined plane of scarf-repaired composite laminates.