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TEAM Workshop Problem 27 -
Eddy Current NDT and Deep Flaws
Gallery SpotlightSensors & NDT
This example demonstrates how MagNet can be used in your NDT/NDE sensor applications. In TEAM Problem 27 "Eddy Current NDT and Deep Flaws", a coil is stationary over a sheet of aluminum that contains a screw hole. Inside of the screw hole, a flaw is to be detected by two Hall effect sensors. The sensors are used to measure the horizontal differential flux density. A snapshot of the model as it appears in MagNet is on the right.
TEAM Problem 27 is solved in MagNet by using the Transient 3D solver. A step waveform is created to power the coil; once the current is shut off, the horizontal flux densities at either end of the screw hole are differenced. The transient solver correctly models induced eddy currents inside the aluminum plate after the current in the coil is turned off. This allows for the calculation of values such as the differential flux density.
TEAM is an acronym for Testing Electromagnetic Analysis Methods, which is a community that creates benchmarks to test finite element analysis software.
METHODS and RESULTS
HORIZONTAL DIFFERENTIAL FLUX DENSITY RESULTS
The graph on the left compares the horizontal differential flux density results computed in MagNet with the experimental results after the current has been shut off.
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SAMPLING FIELD VALUES
All of Infolytica's software packages come bundled with our Field Sampler. This tool allows the user to sample field values at a point, along a line, along an arc, or a grid. The user can graph the results as a function of position, time or parameterized problem. With the Field Sampler, you do not have to model Hall effect sensors, as described in TEAM problem 27; this tool will act as your sensor. A snapshot of the Field Sampler is shown on the left.
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