Eddy Current Modeling
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Eddy Current Simulation of a differential transmit-receive eddy current surface-coil probe detecting a circumferential crack in a heat exchanger tube. This figure includes: A diagram of the probe inside the tube with a circumferential crack. An Isometric C-scan display of the probe signal as it detects the crack. A Topographical display ("clip-plot") of the signal component with a threshold cut-off of 50% of maximum. |
Some geometries modeled by analytic solutions to Maxwell's electromagnetic equations that govern eddy current testing are shown below.
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Transmit-Receive coil geometry with metallic tubular layers (ferromagnetic and nonferromagnetic) both inside the coil windings and external to the windings. Coil and tube axes are coaxial. Calculates signal responses to wall thickness variations, and changes to the conducting and magnetic properties of the layers. |
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Transmit-Receive coil geometry with metallic tubular layers (ferromagnetic and nonferromagnetic) both inside the coil windings and external to the windings. Coil and tube axes are coaxial.
Calculates signals from the coils scanning by small flaws in the tube walls. |
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Transmit-Receive coil geometry with metallic plates (ferromagnetic and nonmagnetic) both above and below pancake-shaped coils. The coil axes are perpendicular to the surfaces of the plates. Calculates probe responses to wall thickness variations, and changes in the conducting and magnetic properties of the plates. |
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Transmit-Receive coil geometry with metallic plates (ferromagnetic and nonmagnetic) both above and below pancake-shaped coils. The coil axes are perpendicular to the surfaces of the plates. Calculates signals from the coils scanning by small flaws (crack-like and volumetric) in the plates. |
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Differential Transmit-Receive coil geometry with metallic plates (ferromagnetic and nonmagnetic) both above and below pancake-shaped coils. The coil axes are perpendicular to the surfaces of the plates. Calculates signals from the coils scanning by small flaws (crack-like and volumetric) in the plates. |
We use the FEM electromagnetics modeling package called MagNet which is distributed by Infolytica Corporation.
We use this package for:
1. Simulating eddy current inspection geometries that are more complicated than those that can be simulated using Analytic solutions.
2. Analyzing and optimizing permanent magnet configurations in magnetic biasing eddy current probes.
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Magnetic Field pattern for a bobbin eddy current probe scanning a tube. This pattern was produced using FEM. |
We use the Volume Integral Modeling software called VIC3D by Victor Technologies, LLC.
This package is used to model probe responses to component flaws of complex shapes.
If you would like further discussion on the information displayed on this page, please feel free to contact Sean Sullivan
Page updated: August 2002
