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Rotating flux-focusing eddy current probe for flaw detection
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Copyright Year | 1997 |
| Description | A flux-focusing electromagnetic sensor which uses a ferromagnetic flux-focusing lens simplifies inspections and increases detectability of fatigue cracks about circular fasteners and other circular inhomogeneities in high conductivity material. The unique feature of the device is the ferrous shield isolating a high-turn pick-up coil from an excitation coil, The use of the magnetic shield is shown to produce a null voltage output across the receiving coil in the presence of an unflawed sample. A redistribution of the current flow in the sample caused by the presence of flaws, however, eliminates the shielding condition and a large output voltage is produced, yielding a clear unambiguous flaw signal. By rotating the probe in a path around a circular fastener such as a rivet while maintaining a constant distance between the probe and the center of a rivet, the signal due to current flow about the rivet can be held constant. Any further changes in the current distribution, such as due to a fatigue crack at the rivet joint, can be detected as an increase in the output voltage above that due to the flow about the rivet head. |
| File Size | 1157460 |
| Page Count | 22 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_20080004633 |
| Archival Resource Key | ark:/13960/t0qr9rf7m |
| Language | English |
| Publisher Date | 1997-07-15 |
| Access Restriction | Open |
| Subject Keyword | Metals And Metallic Materials Patents Cracks Nondestructive Tests Inspection Ferromagnetic Materials Fasteners Detection Rotation Eddy Currents Lenses Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Patent |
