Imaging flaws with a SQUID magnetometer array
Abstract
Magnetic fields produced by current-carrying plates containing a crack or hole, magnetic contamination in machined slots, and remanent magnetization in rocks and photocopier toner have been measured. Magnetic fields from holes as small as 350 microns in conducting plates have been mapped. The measurements demonstrate that these small circular holes and similar-sized cracks can be easily located in conducting plates. The area of the holes in plates may be found by fitting theoretical calculations to the data. Since a SQUID can measure both dc and ac magnetic fields, it should be possible to detect deeper flaws than can conventional eddy current techniques.
- Publication:
-
Review of Progress in Quantitative Nondestructive Evaluation
- Pub Date:
- 1991
- Bibcode:
- 1991qnde...10..979M
- Keywords:
-
- Electric Conductors;
- Magnetic Fields;
- Magnetometers;
- Nondestructive Tests;
- Squid (Detectors);
- Cracks;
- Hole Geometry (Mechanics);
- Magnetic Shielding;
- Magnetization;
- Perforated Plates;
- Instrumentation and Photography