Evaluation of Eddy Current Inspection on the Defects of Unloading vs. Loading Conditions in the Fiber Reinforced Composite Materials

Abstract:

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.

• Periodical: Materials Science Forum (Volumes 475-479)
• Pages: 1063-1066
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.475-479.1063
• Online since: January 2005
• Authors: Cheol Woong Kim, Jeong Soon Lee, Tae Gun Um, Dong Joon Oh, Il Song
• Keywords: Circular Defect, EC Amplitude, Eddy Current EC, Fiber Reinforced Composite Materials (FRCM), Lissajous Figure, MRPC Probe, Phase Angle, Signal-to-Noise Ratio (SNR)

References

[1] Soon-Gi Shin: Self-Diagnosis of GFRP Composites Containing Carbon Powder and Fiber as Electrically Conductive Phases (Metals and Materials International, Korea 2002), Vol. 7, No. 6 , pp.605-611.

DOI: 10.1007/bf03179259

[2] Sam-Hong Song and Cheol-Woong Kim: The Fatigue Crack and Delamination Behavior on the Fuselage-Wing Intersection Containing Variable Notches (International Journal of Modern Physics B, Singapore 2003), Vol. 17, No. 8, pp.1540-1546.

DOI: 10.1142/s0217979203019290

[3] Jung-Kyu Kim and Ki-Weon Kang: Impact Damage Behavior and Evaluation of Residual Strength in Plain Woven Glass/Epoxy Composite (Transactions of the KSME, A, Korea 1999), Vol. 23, No. 2, pp.294-303.

[4] Cheol-Woong Kim, Jeong-Soon Lee, Tae-Gun Um, Hyung-Keun Ahn and Il Song: Evaluation of Delamination Using a Eddy Current Testing for Hybrid Composite Material (The 4 th Korea-Japan Joint Symposium in Composite Materials, Korea 2003) pp.25-26.