Optical Flow Amplitude-Based Method for Detection and Quantitative Evaluation of Impact Damage in CFRP

Carbon fiber-reinforced polymer (CFRP) is widely used in transportation and aerospace. However, CFRP is susceptible to impact damage, leading to defects such as cracks and delamination. Moreover, detecting 4-J low-energy impact damage in CFRP is challenging. To address this issue, this article uses eddy current pulsed thermography (ECPT) in combination with the optical flow amplitude-based method (OFABM) for nondestructive testing. The optical flow is used to track the transient heat propagation state of the CFRP composites, and the principal component analysis (PCA) is employed to extract defect information from the optical flow amplitude. A relationship between optical flow amplitude and impact energy is established, allowing quantitative evaluation of impact damage. The experimental results demonstrate that the OFABM effectively detects 4-J low-energy impact damage in CFRP and has the potential for the quantitative assessment of impact damage.