Affiliations: [a] College of Architecture and Environment, Sichuan University, Chengdu, China | [b] Nondestructive Testing and Structural Reliability Evaluation Laboratory, North Minzu University, Yinchuan, China | [c] Department of Ocean Science and Engineering, Southern University of Science and Technology, Shenzhen, China
Correspondence:
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Corresponding authors: Hongmei Li, College of Architecture and Environment, Sichuan University, Chengdu, 610000, China. E-mail: lihm75@163.com. Chuntian Zhao, College of Architecture and Environment, Sichuan University, Chengdu, 610000, China. E-mail: richard8989@qq.com
Abstract: The defect in structures is the major risk to the structural integrity, thus to perform the defect detections and evaluations efficiently is critical in assuring the structural safety. Magnetic flux leakage testing (MFLT) is an important non-destructive testing (NDT) method. Due to its high testing sensitivity and simple operating procedure, it has been widely used in detecting surface and near-surface defects in ferromagnetic components. To improve the accuracy of defect detection, it is necessary to find a suitable source magnetization distribution around a defect, and furthermore, to correlate the defect with the magnetic leakage signals. In this study, a magnetic charge model is proposed, in which both volume- and surface- densities of magnetic charges around a defect are considered. Then, this model is used for the calculation of the magnetic leakage signals caused by a known complex V-shape defect for the verification purpose. The results from the simulation match very well with that from the experiment. It indicates potentials that the magnetic charge model and the associated approach can be applied in MFLT with improved accuracy.
Keywords: Magnetic flux leakage testing, defect testing and evaluation, magnetic charge model of defect
