USA As Represented by Secretary of the Navy

Paul M Gammell

Susan N Vernon

Brian Sircus

A magnetic field generator positioned externally of a non-ferrous metallic tructure being examined, is rotated at a relatively low speed to produce a rotating magnetic field penetrating the metallic structure to a selected depth as a function of spacing between magnetic poles of the generator parallel to a planar surface of the metallic structure. Traction between the metallic structure and the magnetic field accompanying its rotation is measured. Corrosion of the metallic structure at subsurface depths is detected and quantified from such traction measurements.

Subsurface examination of non-ferrous material for detecting corrosion

Conductive measuring electrodes, of a capacitive probe having a grounded rd electrode positioned therebetween shield a probe circuit, provides mutual capacitance measurements which way as a function of changes in impedance of dielectric material being monitored as it undergoes a curing process. The probe is positioned in non-embedded relation to the dielectric material to form a sensitivity region therein through which an electric field extends between the conductive measuring electrodes of the probe to establish said variable mutual capacitance measurements without extraneous influences.

Non-contacting capacitance probe for dielectric cure monitoring

Acoustical radiation is generated and applied to the bonding interface between a radiation transmission material and a radiation attenuating material to determine adhesion quality by extraction of data from a response signal produced by echoes reflected from both the interface and the radiation entry surface on the radiation transmissive material exposed to the generated acoustical radiation. Signal phase cancellation between the echoes from the entry surface and bonding interface produce a signal signature from which the quality of bonding is evaluated. By partial attenuation of the echo from the entry surface, the signature is maximized.

Phase cancellation enhancement of ultrasonic evaluation of

A compound eddy current probe comprising a nest of concentric ferrite cup re probes. Both the inner and outer radii of the activated coil can be selectively altered by operator or automatic program to correspond with the size and thickness of the material under test.

Field variable, electronically controlled, nested coil eddy current probe

This invention relates to a method for nondestructive inspection (NDI) of mposite materials comprising conductive fibers. The depth of broken fiber damage in nonmetal matrix composites such as graphite/epoxy and carbon/carbon materials may be ascertained and eddy current inspection is extended to include thick metal sections by this method. Inspection is possible with access limited to a single surface.

Eddy current method to measure distance between scanned surface and a

This invention relates to a method and device for measuring the resistivity f 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.

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Silver Spring, MD, United States of America

Paul M Gammell