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Deep Flaw Detection with Giant Magnetoresistive (GMR) Based Self-Nulling ProbeIn this paper a design modification to the Very-Low Frequency GMR Based Self-Nulling Probe has been presented to enable improved signal to noise ratio for deeply buried flaws. The design change consists of incorporating a feedback coil in the center of the flux focusing lens. The use of the feedback coil enables cancellation of the leakage fields in the center of the probe and biasing of the GMR sensor to a location of high magnetic field sensitivity. The effect of the feedback on the probe output was examined, and experimental results for deep flaw detection were presented. The experimental results show that the modified probe is capable of clearly identifying flaws up to 1 cm deep in aluminum alloy structures.
Document ID
20040086500
Acquisition Source
Langley Research Center
Document Type
Preprint (Draft being sent to journal)
Authors
Wincheski, Buzz
(NASA Langley Research Center Hampton, VA, United States)
Namkung, Min
(NASA Langley Research Center Hampton, VA, United States)
Date Acquired
September 7, 2013
Publication Date
January 1, 2004
Subject Category
Electronics And Electrical Engineering
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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