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:

1990-05-01

Pagination or Media Count:

13.0

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