Sensor devices for structural health monitoring

• US 7,986,218 B2
• Filed: 01/04/2006
• Issued: 07/26/2011
• Est. Priority Date: 02/26/1999
• Status: Expired due to Fees

• Current Assignee: Yasumi Capital, LLC (Intellectual Ventures LLC)
• Original Assignee: Yasumi Capital, LLC (Intellectual Ventures LLC)
• Inventors: Priyantha, Namal, Huestis, David L., Jayaweeera, Palitha, Bahr, Alfred J., Watters, David G.
• Primary Examiner(s): Zimmerman; Brian A
• Assistant Examiner(s): Syed; Nabil H
• Application Number:
  US11/326,224
• Publication Number:
  US 20060170535A1
• Time in Patent Office: 2,029 Days
• Field of Search: 340/10.4, 340/10.41, 340/10.1, 340/10.2, 340/10.3, 340/539.1, 340/870.07, 324/693
• US Class Current: 340/10.41
• CPC Class Codes: E01D 22/00 Methods or apparatus for repairing or strengthening existing bridges electrochemical desalination or re-alkalisation C04B41/00; Methods or apparatus for dismantling bridges
• CPC Class Codes: G01D 21/00 Measuring or testing not otherwise provided for
• CPC Class Codes: G01D 5/48 using wave or particle radiation means G01D5/26 takes precedence
• CPC Class Codes: G01K 3/04 in respect of time
• CPC Class Codes: G01K 5/483 using materials with a configuration memory, e.g. Ni-Ti alloys
• CPC Class Codes: G01M 5/0008 of bridges
• CPC Class Codes: G01M 5/0041 by determining deflection or stress
• CPC Class Codes: G01M 5/0083 by measuring variation of impedance, e.g. resistance, capacitance, induction
• CPC Class Codes: G01M 5/0091 by using electromagnetic excitation or detection
• CPC Class Codes: G01N 27/4035 Combination of a single ion-sensing electrode and a single reference electrode G01N27/406 and G01N27/413 take precedence
• CPC Class Codes: G06K 19/0717 the sensor being capable of sensing environmental conditions such as temperature history or pressure
• CPC Class Codes: H04Q 2209/47 using RFID associated with sensors
• CPC Class Codes: H04Q 2209/823 where the data is sent when the measured values exceed a threshold, e.g. sending an alarm
• CPC Class Codes: H04Q 9/00 Arrangements in telecontrol or telemetry systems for selectively calling a substation from a main station, in which substation desired apparatus is selected for applying a control signal thereto or for obtaining measured values therefrom

Abstract

Described herein are wireless interrogation systems and methods that rely on a complementary sensing device and interrogator. The sensing device is disposed to measure a parameter indicative of the health of a structure. A sensor reading from the sensor indicates the level of a parameter being monitored or whether one or more particular physical or chemical events have taken place. Using wireless techniques, the interrogator probes the device to determine its identity and its current sensor reading. This often includes transmission of a wireless signal through portions of the structure. When activated, the device responds with a wireless signal that identifies the device and contains information about the parameter being measured or a particular sensor state corresponding to the parameter. The identity of the device allows it to be distinguished from a number of similar devices. Thus this invention finds particular usefulness in the context of an array of devices that can be probed by a wireless interrogation unit. In one embodiment, the devices are passive and derive power from the interrogation signal.

Claims

1. A device comprising:

an electrochemical cell comprising a reference electrode, an ion selective electrode, and an electrolyte, wherein the electrolyte is configured to provide a medium for movement of ions and to maintain an electrical connection between the reference electrode and the ion selective electrode;

an enclosure including a permeable concrete membrane configured to allow an ion to pass into the electrolyte from outside of the device, wherein the enclosure contains the electrochemical cell;

a sensor configured to determine a potential difference between the reference electrode and the ion selective electrode; and

a transponder in electrical communication with the sensor, wherein the transponder is configured to transmit a wireless signal that includes the potential difference and an identifier associated with the device.

2. The device of claim 1, wherein the ion selective electrode is configured to respond to an ion that facilitates corrosion of a metal.

3. The device of claim 1, wherein the electrolyte is configured to maintain a consistent pH.

4. The device of claim 1, wherein the device is embedded in a structure, and wherein the wireless signal is configured to travel through at least a portion of the structure.

5. The device of claim 4, wherein the structure comprises concrete, and wherein the potential difference is indicative of a chloride ion concentration in the concrete.

6. The device of claim 1, wherein the device comprises a passive device.

7. The device of claim 1, further comprising:

a temperature sensor configured to detect a temperature; and

compensation circuitry configured to compensate the potential difference based at least in part on the temperature.

8. The device of claim 1, further comprising a memory configured to store the identifier, wherein the identifier is specific to the device.

9. The device of claim 1, wherein the wireless signal further includes an indication if the potential difference exceeds a threshold.

10. The device of claim 1, wherein the device is embedded in a structure, and wherein the potential difference is indicative of a health of the structure.

11. A system for monitoring a health of a structure, the system comprising:

an array of devices, wherein each device in the array of devices is embedded in the structure, and wherein each device in the array of devices comprises;

an electrochemical cell comprising a reference electrode, an ion selective electrode, and an electrolyte, wherein the electrolyte is configured to provide a medium for movement of ions between the reference electrode and the ion selective electrode;

an enclosure including a port configured to allow the ions to pass into the electrolyte from outside of the device, wherein the port includes a permeable concrete membrane and the enclosure contains the electrochemical cell;

a sensor configured to detect a parameter relating to the health of the structure and based at least in part on the ions that pass into the electrolyte; and

a transponder in electrical communication with the sensor and configured to transmit a wireless signal to an interrogator, wherein the wireless signal includes the parameter and an identifier associated with the device; and

the interrogator configured to receive the wireless signal.

12. The system of claim 11, wherein each device in the array of devices does not contain a power source.

13. The system of claim 12, wherein the interrogator is configured to power each device in the array of devices through a wireless interrogation signal, wherein the wireless interrogation signal is also configured to prompt the wireless signal from each device.

14. The system of claim 11, wherein the interrogator is configured to communicate with a database that includes the identifier associated with each device in the array of devices.

15. The system of claim 14, wherein the database comprises a set of records that identify a location of each device in the array of devices.

16. The system of claim 11, wherein the parameter comprises a quantity of or a state of a chemical species that affects the health of the structure.

17. The system of claim 11, wherein the interrogator is carried by a moving vehicle.

18. A method comprising:

embedding a sensor device in a structure, wherein the sensor device includes a sensor configured to detect a value of a parameter relating to a health of the structure, wherein the value of the parameter is based at least in part on ions in an electrolyte, and wherein the electrolyte is configured to provide a medium for movement of ions between a reference electrode of the sensor device and an ion selective electrode of the sensor device;

receiving an ion at the sensor device through a permeable concrete membrane of an enclosure configured to allow the ion to pass into the electrolyte from outside of the sensor device, wherein the enclosure contains the electrolyte;

detecting the value of the parameter using the sensor;

communicating the value of the parameter to an interrogator in response to a wireless interrogation signal received from the interrogator.

19. The method of claim 18, wherein the structure is a bridge or a portion of a bridge.

20. The method of claim 19, wherein the sensor device is embedded in concrete of the structure using a back filled core.

21. The method of claim 20, wherein the back filled core comprises a low porosity concrete.

22. The method of claim 18, wherein the interrogator is carried by a moving vehicle while communicating with the sensor device.

23. The method of claim 18, wherein the interrogator is carried by a person while communicating with the sensor device.

24. The method of claim 18, further comprising saving the value of the parameter in a database.

25. The method of claim 18, further comprising compensating the value of the parameter based at least in part on a temperature detected by the sensor device.

26. The method of claim 18, wherein the wireless interrogation signal further comprises power for the sensor device.

27. The method of claim 18, wherein the value of the parameter is communicated to the interrogator in a wireless signal, and wherein the wireless signal also includes an identifier associated with the sensor device.