Detection of fracture crack in carbon fiber reinforced polymer (CFRP) cables based on microfocus x-ray imaging

Abstract The extensive application of carbon fiber reinforced polymer (CFRP) cables in engineering is due to their excellent mechanical properties. However, current non-destructive testing methods struggle to detect defects and damages within CFRP cables. To address this issue, the mechanisms and technical methods for identifying internal defects in CFRP cables using advanced microfocus x-ray imaging were studied. The internal fracture of the CFRP cable influences the attenuation characteristics of x-ray propagation, thereby reflecting a grayscale difference from the non-destructive area in the image, which is crucial for defect detection. To simulate slight, moderate, and full section fractures, three internal artificial fracture specimens were manufactured, each with three degrees of prefabricated defects. In order to achieve high-precision detection, the x-ray imaging device equipped with microfocus tubes was employed to detect CFRP cable specimens from three angles of 0°, 120°, and 240° relative to the initial position. A comprehensive set of methods was developed for the precise localization and quantification of fracture cracks, and applied in acquired x-ray images. The results indicated that the proposed approach can accurately identify both the location and magnitude of fractures inside CFRP cables, and has strong robustness to radiation energy levels. The proposed method offers non-destructive testing technology support for professionals in bridge and ocean engineering.