The research on the flaw classification and identification of the PEC NDT technology

Issue title: Selected Papers from the 14th International Symposium on Applied Electromagnetics and Mechanics (ISEM 2009), Part II

Article type: Research Article

Authors: Wang, Haitao^{a; *} | Zhang, Binqiang^a | Tian, G.Y.^{a; b} | Zhou, Deqiang^a | Wang, Ping^a | Li, Yong^b

Affiliations: [a] School of automation engineering, Nanjing University of Aeronautics and Astronautics, Nanjing, Jiangsu, 210016 P. R. China | [b] University of Newcastle upon Tyne, Newcastle, NE 7RU, UK

Correspondence: [*] Corresponding author: Haitao Wang, Tel.: +86 25 84896264; Fax: +86 25 84892368; E-mail: htwang@nuaa.edu.cn; whtlqf@hotmail

Abstract: Pulsed Eddy Current (PEC) NDT has played a vital role in detection and classification of the surface and sub-surface defects in conductive structures. Normally, it uses peak values of the acquired transient field signals, and the combination of the feature values of the time of the peak to identify flaws with the help of Principal Component Analysis (PCA). However, it is found that the random noise undermines the classification results, because PCA works robustly only in the time domain. In the light of this drawback, the fundamental and the first-harmonic components are investigated and taken as the new feature values in the frequency domain. Through the analysis of the feature values in both time and frequency domains, the influence of random noise is mitigated. Consequently, surface defects, subsurface defects and metal thickness changes are classified with much higher identification accuracy.

Keywords: Pulsed Eddy Current, the fundamental component, the first harmonic component, defect

DOI: 10.3233/JAE-2010-1259

Journal: International Journal of Applied Electromagnetics and Mechanics, vol. 33, no. 3-4, pp. 1343-1349, 2010