A simple evaluation of magnetic fields and eddy currents in ferromagnetic straps of finite length

In this paper, we present an eddy current transducer with rotating permanent magnets for the inspection of planar conducting plates. The transducer consists of a rotating head with permanent magnets, which is used to generate variable magnetic fields and thus induce eddy currents in the tested material. Two Hall sensors connected in a differential manner are used to detect a nonuniform distribution of eddy currents induced in a specimen containing a defect. To prove the usability of the transducer, a number of experiments were conducted on thick aluminum samples containing notches at different depths. Selected results of the achieved measurements are presented.

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Investigation of welds by the method of the magneto-optical eddy current flaw detection

EPJ Web of Conferences ◽

10.1051/epjconf/201818502014 ◽

2018 ◽

Vol 185 ◽

pp. 02014 ◽

Cited By ~ 1

Author(s):

Nazar Lugovskoy ◽

Vladimir Berzhansky ◽

Dmitry Filippov ◽

Anatoliy Prokopov ◽

Alexandr Shuyskyy

Keyword(s):

Mathematical Modeling ◽

Magnetic Fields ◽

Eddy Current ◽

Eddy Currents ◽

Flaw Detection ◽

Current Method ◽

Epitaxial Films ◽

Eddy Current Method ◽

Ferrite Garnet ◽

Conducting Materials

The paper deals with the magneto-optical eddy current method of flaw detection of conducting materials, in which epitaxial films of ferrite garnet are used as sensors. In particular, the possibilities of visualization of welded seams in magnetic and non-magnetic samples, as well as the defectoscopy of the seams themselves, are considered. The second part of the work is devoted to mathematical modeling of the distribution of the magnetic fields of eddy currents near similar defects.

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The loss of energy in metal plates of finite thickness, due to eddy currents produced by alternating magnetic fields

Proceedings of the Royal Society of London. Series A, Containing Papers of a Mathematical and Physical Character ◽

10.1098/rspa.1926.0084 ◽

1926 ◽

Vol 111 (759) ◽

pp. 604-614 ◽

Cited By ~ 1

Keyword(s):

Magnetic Field ◽

Magnetic Fields ◽

Eddy Currents ◽

Finite Thickness ◽

Metal Plate ◽

The Self ◽

Alternating Magnetic Field ◽

Metal Plates ◽

Alternating Magnetic Fields

The induction of eddy currents in metal plates which are subjected to alternating magnetic fields has been discussed by Clerk-Maxwell, J. J. Thomson and many others. When an alternating magnetic field is produced normal to the surface of a metal plate, eddy currents are induced at the surface of the plate, which gradually penetrate its interior, the current dying away as it penetrates more deeply into the metal. The diffusion of the currents into the plate depends upon the self-induction and resistance of the paths along which they flow, and can be calculated by the same kind of formula as is used for determining the conduction of heat through a metal slab.

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Transient magnetic field formulation for solid source conductors

International Journal of Applied Electromagnetics and Mechanics ◽

10.3233/jae-209475 ◽

2020 ◽

Vol 64 (1-4) ◽

pp. 1539-1545

Author(s):

Georg Wimmer ◽

Sebastian Lange

Keyword(s):

Magnetic Field ◽

Magnetic Fields ◽

Vector Potential ◽

Numerical Scheme ◽

Eddy Currents ◽

Magnetic Vector Potential ◽

Magnetic Vector ◽

Time Step ◽

Azimuthal Component ◽

Transient Magnetic Fields

The formulation for the azimuthal component of the magnetic vector potential for axisymmetric magnetostatic applications is well known. However for transient magnetic fields with solid source conductors and eddy currents the formulation has to be revised. A variable transformation is introduced to remove the singularity from the numerical scheme. The numerical error cannot accumulate and is put instead to the postprocessing at every time step.

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