Delamination detection in bimetallic composite using laser ultrasonic bulk waves

Abstract

In this study, a method based on laser ultrasonic bulk waves is used to detect delamina-tion in a bimetallic composite. For this purpose, several artificial delamination defects were created in a copper-aluminum sample using wire-electrode cutting. The research includes numerical simulation and experimental analysis. The propagation process of laser ultrasonic in Cu/Al bimetallic composite, the interaction between bulk waves and composite interface, and the effect of delami-nation defects on the ultrasound field were studied by numerical simulation. Suitable parameters and features were determined by numerical simulation, which provided a basis for the parameter selection of experimental research. The reflected shear waves from the composite interface can act as a sensitive feature to detect the delamination in Cu/Al bimetallic composites. The distance between the detection point and the excitation point was set to 2 mm to take into account the detection resolution and efficiency. The experimental results were in good agreement with the simulation results, and the C-scan image can intuitively show the location and size of delamination de-fects. The detection method based on laser ultrasonic bulk waves can effectively detect the de-lamination in Cu/Al bimetallic composite, which is suitable for the on-line detection of the rolling composite process.