Quantitative non-destructive evaluation of CFRP delamination defect using laser induced chirp-pulsed radar photothermal tomography

In this paper, a new depth-resolved tomography approach titled laser induced chirp-pulsed radar photothermal tomography (CR-PT) is introduced, and it is employed for the 3D visualization detection for carbon fiber reinforced polymer (CFRP). Initially, the time delay correlation dual orthogonal demodulation (DOD) algorithm is applied to extract the time/frequency-domain characteristic sequence of the chirp-pulsed radar signal, and the applicability of CR-PT is analyzed by COMSOL simulation environment. Subsequently, the correctness of the simulation analysis is verified by the experiment of detecting CFRP with the flat bottom holes by CR-PT. Meanwhile, the accuracy of the shape, position, and depth of the defects detected by CR-PT is determined. Finally, the immersion ultrasonic C-scan imaging and CR-PT are employed to compare and analyze the delamination defect of CFRP composites, which proved the superiority of CR-PT. The experimental results illustrated that CR-PT technique can achieve high-quality 3D geometric reconstruction of CFRP delamination defect, which provides a new attempt and method for quantitative non-destructive evaluation and tomography of CFRP composites.