Accession Number : ADD014571

Title :   Eddy Current Method for Measuring Electrical Resistivity and Device for Providing Accurate Phase Detection.

Descriptive Note : Patent, Filed 9 Jan 89, patented 1 May 90,

Corporate Author : DEPARTMENT OF THE NAVY WASHINGTON DC

Personal Author(s) : Vernon, Susan N ; Gammell, Paul M

Report Date : 01 May 1990

Pagination or Media Count : 13

Abstract : 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)

Descriptors :   *CALIBRATION, *NONDESTRUCTIVE TESTING, ACCURACY, CARBON FIBERS, CARBON REINFORCED COMPOSITES, EDDY CURRENTS, ELECTRICAL RESISTANCE, FIBER REINFORCED COMPOSITES, FREQUENCY, INSPECTION, MATERIALS, MEASUREMENT, PERMEABILITY(MAGNETIC), PHASE DETECTORS, RESISTANCE, SIDES, STANDARDS, SURFACES

Subject Categories : Test Facilities, Equipment and Methods

Distribution Statement : APPROVED FOR PUBLIC RELEASE