Eddy Current Method for Measuring Electrical Resistivity and Device for Providing Accurate Phase Detection.
Patent, Filed 9 Jan 89, patented 1 May 90,
DEPARTMENT OF THE NAVY WASHINGTON DC
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This invention relates to a method and devices for measuring the resistivity of materials. In particular, the methods measure resistivity in carbon fiber reinforced composites as well as any materials with a relative magnetic permeability of 1. The measurement may be made with access restricted to a single side of the material under test. The present invention relates to the field of nondestructive inspection of materials. In particular, this invention involves methods and a device of eddy current inspection for estimating the electrical resistivity of materials. While the method applies to all materials with a relative magnetic permeability of 1, it is particularly useful when the test material falls in one or more of three categories 1 the resistivity falls within a range for which there are no calibration standards 2 only one surface of the test material is accessible and 3 the resistivity is frequency dependent and must be determined over a particular range of frequencies. Keywords Patents, PAT-CL-320-236. JES
- Test Facilities, Equipment and Methods