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

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