Affiliations: Department of Mechanical and Energy Systems Engineering, Oita University, Oita, Japan
Correspondence:
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Corresponding author: Akira Fujii, Department of Mechanical and Energy Systems Engineering, Oita University, Oita 870-1192, Japan. Tel.: +81 97 554 7795; Fax: +81 97 554 7790; E-mail:Fujii.Akira@jeed.or.jp
Abstract: In the inspection of the steel wall of the tank in the
petrochemical plant etc., it is necessary to detect the opposite side defect
from the surface of the steel wall. In this paper, the electromagnetic
inspection method using alternating (ac) and static (dc) magnetic field is
proposed. And, this method is investigated by verification experiment and
3-D nonlinear finite-element method (FEM) taking account of hysteresis
(minor loop) and eddy current. It is shown that the detection of opposite
side defect is possible by the differential permeability of minor loop of
which the position on the hysteresis loop is affected by the existence of
defect.
Keywords: 3-D nonlinear FEM, non-destructive inspection, opposite side defect in steel plate, alternating and static magnetic field, minor loop magnetism property
