Rectangular wave eddy current testing using for imaging of backside defects of steel plates

Issue title: Selected papers from the International Symposium on Applied Electromagnetics and Mechanics - ISEM 2019

Guest editors: Jinhao Qiu, Ke Xiong and Hongli Ji

Article type: Research Article

Authors: Sasayama, Teruyoshi^a; | Yoshimura, Wataru^a | Enpuku, Keiji^a

Affiliations: [a] Kyushu University, Fukuoka, Japan

Correspondence: [*] Corresponding author: Teruyoshi Sasayama, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, Japan. E-mail: [email protected]

Abstract: Accurate, easy, and fast inspection of defects on the backside of thick steel plates is essential for the maintenance of infrastructures. Low frequency eddy current testing (LF-ECT) is a promising method to detect defects of the backside of steel plates, with a thickness of approximately 10 mm. However, it is possible that the signal from the backside defect is smaller than that from the surface magnetic noise, causing difficulty identifying the backside defect. In this study, we propose a method to reduce the surface noise by employing a square wave inverter to generate a harmonic signal (rectangular wave ECT, or RECT), and the result demonstrates that the surface noise is successfully reduced using the harmonic signal.

Keywords: Eddy current testing, ferromagnetic material, low frequency, square wave inverter, rectangular wave ECT

DOI: 10.3233/JAE-209329

Journal: International Journal of Applied Electromagnetics and Mechanics, vol. 64, no. 1-4, pp. 255-262, 2020