Study on the laser ultrasonic testing mechanism of delamination defects in anisotropic curved structure carbon fiber–reinforced polymer

In response to the demand for real-time non-destructive detection of delamination defects in curved structure carbon fiber–reinforced polymer (CFRP), an anisotropic CFRP model was constructed based on the laser thermal elastic effect, and the generation and propagation of ultrasonic waves inside CFPR were analyzed. On this basis, the orientation information of the delamination defect is obtained by calculating the time it takes for the ultrasonic transverse wave to reach the CFRP surface probe after encountering the delamination defect. When the delamination defect with the size of 1×0.2 mm is located between the first and second layers, the detection errors at different probe positions are 0.48% and 0.64%, respectively. Moreover, when the defect is located between the second and third layers, the detection error can also be controlled within 1%.