Evaluation of Eddy Current Inspection on the Defects of Unloading vs. Loading Conditions in the Fiber Reinforced Composite Materials
It had been impossible to inspect the Eddy Current (EC) since the Fiber Reinforced Composite Materials (FRCM) had the low electric conductivity of resin layer. However, it has been successful for our previous research to inspect the defect using the EC. In the case of loading to FRCM, the researches of relationship between the failure behavior and the variation of EC signals have not been carried out. Therefore, this research focused on the comparison and the evaluation of the EC signals according to the variation of the defect depth using the unloading and the radial-loading FRCM tube. We obtained results are as follow. Firstly, The EC signals similar to that of the unloading specimens could be obtained from the loading specimen of 80% defect. Secondly, Regardless of the unloading and the loading specimens, the defect of 100% and 80% depths had the similar phase angles and Lissajous figures. Finally, it was guessed that the length of micro-cracks distributed at the whole specimens under the loading was less than 60% of the specimen thickness.
Z.Y. Zhong, H. Saka, T.H. Kim, E.A. Holm, Y.F. Han and X.S. Xie
C. W. Kim et al., "Evaluation of Eddy Current Inspection on the Defects of Unloading vs. Loading Conditions in the Fiber Reinforced Composite Materials", Materials Science Forum, Vols. 475-479, pp. 1063-1066, 2005