Detection on Medium-frequency Eddy Current C-scan Imaging for Delamination Defects in Carbon Fiber Reinforced Polymer

Among different damages induced by the preparation process and service stage of carbon fiber reinforced polymer (CFRP), delamination defect has the strongest destructiveness. Aiming at the detection of delamination defects in CFRP, a medium-frequency eddy current C-scan imaging method was used for imaging visualization of the delamination defects in carbon fiber composite plate. Based on the imaging results of eddy current C-scan, a statistical model of reconstructing defect areas was established and quantitatively evaluated the detection accuracy by analyzing the influence of different thresholds on the reconstruction area. Then, the change pattern of the defect depth and eddy current characteristic curve was studied, and the detection capability of eddy current to the depth of delamination defects in CFRP plate was investigated. Experimental results show that the established medium-frequency eddy current C-scan imaging system can achieve C-scan imaging and quantitative evaluation of delamination defects with a minimum diameter of 5 mm and depth of 0.5 mm in carbon fiber composite plates. This research provides a feasible approach for quantitative nondestructive evaluation of delamination defects in carbon fiber composite plates.