SBIR-STTR Award

Superconductive quantum interference devices (SQUIDs), patterned in copper oxide superconductor, offer new technology for eddy current evaluation of airframes, using pulsed currents. Their high sensitivity at low frequencies, with minute pickup loops, enables arrays that can give scanned images of submillimeter fatigue cracks and corrosion hidden in underlayers of airframes, without requiring disassembly. High temperature superconductors can bring the arrays into common use. They enable packaging them in a hand-held, refrigerated instrument without cryogenic encumbrances. It would give a hand-held, electromagnetic microscope for eddy current inspection of underlayers, using pulsed currents. Work in Phase I develops the cryogenic and electronic design of a hand-held, electromagnetic microscope, gives an analytical description of its expected performance, and examines its feasibility by testing a single element of an array.Anticipated Results/Potential Commercial Applications-of Results:Successful development of a hand-held, electromagnetic microscope would overcome limitations of conventional eddy current methods. It would enable inspections of underlayers to depths of 15 mm (0.59 in.) or so, thereby saving labor costs of extensive teardowns. It would find common use in inspection of aging airframes of commercial fleets and significantly enhance their safety

Superconductive Quantum Interference Devices (SQUID) patterned in copper oxide superconductor, offer new technology for eddy current evaluation of air-frames, using pulsed currents. Their high sensitivity at low frequencies, with minute pickup loops, enables arrays that can give tomographic images of sub millimeter fatigue cracks and corrosion hidden in underlayers of airframes, without teardowns. High temperature superconductors can bring the arrays into common use. They enable packaging them in a hand-held, refrigerated instrument without cryogenic encumbrances. It would give a hand-held, electromagnetic microscope for eddy current inspection of sublayers, using pulsed currents.Work in Phase II develops a prototype instrument, validates its performance at the Aging Aircraft Nondestructive Inspection Development and Demonstration Center (AANC), and sets a plan for transferring the technology to commercial use.

Anticipated Results/Potential Commercial Applications of Research:
:Successful development of a hand-held, electromagnetic microscope would overcome limitations of conventional eddy current methods. It would enable inspections of underlayers to depths of 15 mm (0.59 inches) or so, thereby saving labor costs of extensive teardowns. It would find common use in inspection of aging airframes of commercial fleets and significantly enhance their safety.Key Words: pulsed eddy currents, eddy current arrays, SQUIDS, aging aircraft, nondestructive evaluation