International Telemetering Conference Proceedings / October 17-20, 1988 / Riviera Hotel, Las Vegas, Nevada / Fine cracks and irregularities on a fast moving conducting surface were detected by the use of microwave and millimeter wave radio responder techniques. The interrogation angle was restricted to an oblique incidence angle less than ±0.5 degree from the surface. The fast moving conducting surface was surrounded by both fast moving and stationary reflective conducting structures. Experimental methods and results from a fine crack 0.1 mm wide, 0.9 mm deep, and 25 mm long on a conducting surface travelling with a speed of 20.23 m/s and measured at 10.525 GH(z) and 73 GH(z) are presented. The reflection-type microwave radio responder consisted of a 10.525 GH(z) 50 mW Gunn diode cw transmitter, a circulator, and a horn antenna used as the interrogator. The receiver in the same responder consisted of the same horn antenna, the circulator and detector diode. The detector diode output was observed with a Norland 3106R digital memory oscilloscope. A reflex kylstron VA 250 was used as the transmitter signal source for the millimeter wave responder. There was a distinct difference between the responder output patterns with uncracked and cracked surfaces. It is therefore possible to use this type of responder for hair-line crack detection of fast moving conducting surfaces. It was also found that this type of radio responder can detect the surface irregularity even before the hairline crack actually occurs.
| Identifer | oai:union.ndltd.org:arizona.edu/oai:arizona.openrepository.com:10150/615034 |
| Date | 10 1900 |
| Creators | Ishii, T. Koryu |
| Contributors | Marquette University |
| Publisher | International Foundation for Telemetering |
| Source Sets | University of Arizona |
| Language | en_US |
| Detected Language | English |
| Type | text, Proceedings |
| Rights | Copyright © International Foundation for Telemetering |
| Relation | http://www.telemetry.org/ |
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