Wireless Microsensors Monitor Structural Health
Wireless microsensors integrate RFIDs with sensors to enable rapid
wireless
interrogation of the health of structures. These passive devices can be
embedded in the structure to provide an indication of internal damage.
The SensorTag concept is a powerful idea that has wide ranging
dimensions and applications. One dimension is the integration of other
sensors, such as pressure, flow, and strain. Another dimension is
structural. SensorTag devices could be embedded in buildings,
automobiles, aircraft, and as a part of industrial process control to
provide the needed health monitoring for these structures.
SensorTags™ Detect Over-temperature Exposure on the
Space Shuttle
For one customer, NASA, we developed temperature over-limit
sensors. Prototype devices
survive 400 C and provide over-limit indication at some
pre-determined temperature less than 400 C. These SensorTags are
designed to be embedded
in a 2-mm gap between tiles on the U.S. Space Shuttle to monitor
possible over-temperature conditions on atmospheric reentry.
Over-temperature
indication is an important quantity to sense in commercial/industrial
environments--inventory control, shipping, steam-sterilization,
etc.
Smart Pebbles™ Warn of Impending Corrosion in Bridge
Decks
For another customer, California Department of Transportation, we
developed chloride threshold sensors (Smart PebblesTM).
These devices would be embedded known locations in bridge decks to
monitor chloride ingress of time. Knowledge of
chloride diffusion into bridge-deck concrete is important in
prioritizing remediation steps to protect the underlying rebar from
corrosion. A
van-mounted reader could drive over the bridge to obtain
chloride-threshold data from the embedded sensors. Using GPS
positioning, the
van could automatically update the health of the bridge in the bridge
database.
Publications, Presentations, and Patents
- J.B. Pallix, F.S. Milos, and D.L. Huestis, "Subsurface
Microsensors for Assisted Recertification of TPS (SmarTPS)," Sixth
Annual International Conference on Composites Engineering (ICCE/6)
(Orlando, FL, June 27-July 3, 1999) [Proceedings edited by D. Hui,
published by ICCE and College of Engineering, University of New Orleans,
1999].
- F. S. Milos, D. G. Watters, J. B. Pallix, A.
J. Bahr, and D. L. Huestis, "Wireless Subsurface Microsensors for
Health Monitoring of Thermal Projection Systems on Hypersonic Venicles,"
Advanced Nondestructive Evaluation for Structural and Biological
Health Monitoring (Newport Beach, CA, 6-8 March 2001) [T. Kundu,
Ed., Proc. SPIE 4335, 74-82 (2001)].
- D. G. Watters, P. Jayaweera, A. J. Bahr, and
D. L. Huestis, "Design and Performance of Wireless Sensors for Structural
Health Monitoring,"
Review of Progress in Quantitative NDE (Brunswick,
ME, July 29-August 3, 2001) [Review of Progress in Quantitative
Nondestructive Evaluation, Vol. 21A, pp.969-976, D. O. Thompson and
D. E. Chimenti, Eds. (Am. Inst. Phys., Melville, NY, 2001)].
- D. G. Watters, D. L. Huestis, A. J. Bahr, and R. J. Vidmar,
"Event-Recording Devices with Identification Codes," United States
Patent No. 6,617,963 (issued September 9, 2003).
- D. G. Watters, D. L. Huestis, and A. J. Bahr, "Wireless Event-
Recording Device with Identification Codes," United States
Patent No. 6,806,808 (issued October 19, 2004).
- D. G. Watters, D. L. Huestis, A. J. Bahr, N. Priyantha, and
P. Jayaweera, "Sensor Devices for Structural Health Monitoring," United States
Patent No. 7,034,660 (issued April 25, 2006).
SRI Contacts
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(10/02/07)
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