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Aging Wire Insulation Assessment by Phase Spectrum Examination of Ultrasonic Guided WavesWire integrity has become an area of concern to the aerospace community including DoD, NASA, FAA, and Industry. Over time and changing environmental conditions, wire insulation can become brittle and crack. The cracks expose the wire conductor and can be a source of equipment failure, short circuits, smoke, and fire. The technique of using the ultrasonic phase spectrum to extract material properties of the insulation is being examined. Ultrasonic guided waves will propagate in both the wire conductor and insulation. Assuming the condition of the conductor remains constant then the stiffness of the insulator can be determined by measuring the ultrasonic guided wave velocity. In the phase spectrum method the guided wave velocity is obtained by transforming the time base waveform to the frequency domain and taking the phase difference between two waveforms. The result can then be correlated with a database, derived by numerical model calculations, to extract material properties of the wire insulator. Initial laboratory tests were performed on a simple model consisting of a solid cylinder and then a solid cylinder with a polymer coating. For each sample the flexural mode waveform was identified. That waveform was then transformed to the frequency domain and a phase spectrum was calculated from a pair of waveforms. Experimental results on the simple model compared well to numerical calculations. Further tests were conducted on aircraft or mil-spec wire samples, to see if changes in wire insulation stiffness can be extracted using the phase spectrum technique.
Document ID
20040085735
Acquisition Source
Langley Research Center
Document Type
Conference Paper
Authors
Anastasi, Robert F.
(Army Research Lab. Hampton, VA, United States)
Madaras, Eric I.
(NASA Langley Research Center Hampton, VA, United States)
Date Acquired
September 7, 2013
Publication Date
January 1, 2003
Subject Category
Electronics And Electrical Engineering
Report/Patent Number
Paper 29
Meeting Information
Meeting: SPIE''s 8th International Symposium on NDE for Health Monitoring and Diagnostics
Location: San Diego, CA
Country: United States
Start Date: March 2, 2003
End Date: March 6, 2003
Sponsors: International Society for Optical Engineering
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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