As for the alternating magnetic flux leakage testing of non-destructive inspection, the alternating magnetic field with high frequency is used. Therefore, this inspection method is not used for inspection of the opposite side defect in the steel plate. In this paper, the inspection method of the opposite side defect in the steel plate is proposed by this inspection method using the magnetizing current of the square wave on direct-current bias. This inspection principle is investigated by 3-D nonlinear FEM analysis taking account of magnetizing properties of minor loop and eddy current in the steel plate.
GotohY. and TakahashiN., Evaluation of detecting method with ac and dc excitations of opposite side defect in steel using 3d non-linear FEM taking account of minor loop, IEEE Trans. Magn.44(6) (2008), 1622–1625.
2.
LiY.WilsonJ. and TianG.Y., Experiment and simulation study of 3D magnetic field sensing for magnetic flux leakage defect characterisation, NDT&E INT40(2) (2007), 179–184.
3.
ParkG.S. and ParkE.S., Improvement of the sensor system in magnetic flux leakage-type nondestructive testing (NDT), IEEE Trans. Magn.38(2) (2002), 1277–1280.
4.
KatohM.MasumotoN.NishioK. and YamaguchiT., Modeling of the yoke-magnetization in MFL-testing by finite element, NDT&E INT36(7) (2003), 479–486.
5.
ZhangY.YeZ. and WangC., A fast method for rectangular crack sizes reconstruction in magnetic flux leakage testing, NDT&E INT42(5) (2009), 369–375.
6.
AI-NaemiF.I.HallJ.P. and MoA.J., FEM modeling techniques of magnetic flux leakage-type NDT for ferromagnetic plate inspection, J. Magn. Magn. Mater.304(2) (2006), 790–793.
7.
MiyataK.OhashiK.MuraokaA. and TakahashiN., 3-D magnetic field analysis of permanent-magnet type of MRI taking account of minor loop, IEEE Trans. Magn.42(4) (2006), 1451–1454.
