The signal characteristics of rectangular induction coil affected by sensor arrangement and scanning direction in MFL application

Abstract

To improve the accuracy of the magnetic flux leakage(MFL) testing in practical application, we analyzed the signal characteristics of rectangular induction coil affected by the sensor arrangement and scanning direction. On the basis of magnetic dipole theory, the descriptions for the MFL field distributions of standard discontinuity were established. Further, based on Faraday's law of induction, the signal characteristics of rectangular induction coils were calculated and it was found that the signal waveform of the horizontal coil is similar with the x component of MFL; in contrast, the signal waveform of the vertical one has the same changing trend with the z component of MFL. Finally, the influence of scanning direction was analyzed and found that different scanning directions will generate different signal characteristics; and that with the angle β between the coil and discontinuity orientation changing from 0 toπ/2, the signal amplitudes of both induction coils decrease, which was verified by relevant experiments.

Keywords

MFL (magnetic flux leakage)induction coil output signal characteristic arrangement direction scanning direction

References

Dutta

S.M.

, Magnetic Flux Leakage Sensing: The forward and Inverse Problem, Ph.D.thesis, Rice University, Houston, Texas, 2008.

API, Petroleum and Nature Gas Industries-Steel Pipe for Pipeline Transportation Systems, Specification for Line Pipe, American Petroleum Institute, Specification 5L, No. 44, Washington, D.C., 2008.

Kang

, Wu

and Sun

, The Use of MFL Method and Apparatus for Steel Pipe, Materials Evaluation70(7) (July 2012), 821-827.

Sun

, Wu

, Feng

and Kang

, An opening electric-MFL detector for the NDT of in-service mine hoist wire [J], IEEE Sensors Journal14(6) (2014), 2042-2047.

Bray

D.E.

and Stanley

R.K.

, Magnetic Flux Leakage Techniques in Nondestructive Evaluation Basic Magnetism for NDE, Nondestructive Evaluation: A Tool in Design, Manufacturing and Service, CRC Press, Dec. 1996, pp. 289-291.

, Sun

, Kang

and Yang

, Theoretical analyses of MFL signal affected by discontinuity orientation and sensor-scanning direction [J], IEEE Transactions on Magnetics51(1) (2015), 207-213.

, Wilson

and Tian

G.Y.

, Experiment and simulation study of 3D magnetic field sensing for magnetic flux leakage defect characterization, NDT&E International, No. 40, 2007, 179-184.

Ahamed

S.V.

and Erdelyi

E.A.

, Flux Distribution in D. C. Machines On-Load and Overloads, Institute of Electrical and Electronics Engineers, Transactions on Power Apparatus and SystemsPAS-85(9) (Sept. 1966), 960-967.

Silvester

and Chari

M.V.K.

, Finite Element Solution of Saturable Magnetic Field Problem, Institute of Electrical and Electronics Engineers, Transactions on Power Apparatus and SystemsPAS-89(7) (Sept.-Oct. 1970), 1642-1651.

10.

, Kang

, Tu

and Sun

, Analysis of the eddy-current effect in the Hi-speed axial MFL testing for steel pipe [J], International Journal of Applied Electromagnetics and Mechanics45 (2014), 193-199.

11.

Wilson

and Tian

G.Y.

, 3D magnetic field sensing for magnetic flux leakage defect characterization, Insight48(6) (2006), 357-359.

12.

Mandache

and Clapham

, A model for magnetic flux leakage signal predictions, J. Phys. D: Appl. Phys36 (2003), 2427-2431.

13.

Zatsepin

and Shcherbinin

, Calculation of Magneto static field of surface defects. I. Field topography of defects model, Defektoskopiya50(5) (1966), 50-59.

14.

Shcherbinin

and Pashagin

, Influence of the extension of a defect on the magnitude of its magnetic field, Defektoskopiya8(4) (Mar 1972), 74-83.