Damage Detection/Locating System Providing Thermal Protection

• US 20070183110A1
• Filed: 02/05/2007
• Published: 08/09/2007
• Est. Priority Date: 02/06/2006
• Status: Active Grant

• Current Assignee: United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration
• Original Assignee: National Aeronautics and Space Administration (Government of the United States of America)
• Inventors: Taylor, Bryant D., Woodard, Stanley E., Shams, Qamar A., Jones, Thomas W.
• Granted Patent: US 7,683,797 B2
• Time in Patent Office: Days
• US Class Current: 361/103
• CPC Class Codes: G01R 33/02 Measuring direction or magnitude of magnetic fields or magnetic flux G01R33/20 takes precedence

Abstract

A damage locating system also provides thermal protection. An array of sensors substantially tiles an area of interest. Each sensor is a reflective-surface conductor having operatively coupled inductance and capacitance. A magnetic field response recorder is provided to interrogate each sensor before and after a damage condition. Changes in response are indicative of damage and a corresponding location thereof.

Claims

1. A damage locating system providing thermal protection, comprising:

at least one chain substantially tiling an area of interest, each said chain defined by an alternating arrangement of capacitors and inductors connected in parallel, each of said capacitors being a reflective-surface interdigitated-electrodes capacitor and each of said inductors being a reflective-surface spiral inductor; and

a magnetic field response recorder for interrogating each said chain prior to damage thereof to establish a baseline frequency response for each said chain, and for interrogating each said chain after damage thereto wherein changes from said baseline frequency response for any said chain are indicative of damage thereto and a corresponding location thereof.

2. A damage locating system as in claim 1 wherein each said chain is fabricated as a thin film.

3. A damage locating system as in claim 1 wherein each said chain has a unique baseline frequency response.

4. A damage locating system as in claim 1 wherein, for each said chain, each of said capacitors is electrically connected in parallel to an adjoining one of said inductors to define an adjoining capacitor-inductor pair, and wherein said baseline frequency response comprises a band of frequencies with a unique portion of said band corresponding to one of said adjoining capacitor-inductor pairs.

5. A damage locating system providing thermal protection, comprising:

a non-conductive substrate material;

at least one electrical circuit deposited on said substrate material to substantially tile an area of interest thereon, each said circuit defined by an alternating arrangement of capacitors and inductors connected in parallel, each of said capacitors being a reflective-surface interdigitated-electrodes capacitor and each of said inductors being a reflective-surface spiral inductor; and

a magnetic field response recorder for interrogating each said circuit prior to damage thereof to establish a baseline frequency response for each said circuit, and for interrogating each said circuit after damage thereto wherein changes from said baseline frequency response for any said circuit are indicative of damage thereto and a corresponding location thereof.

6. A damage locating system as in claim 5 wherein each said circuit is fabricated as a thin film.

7. A damage locating system as in claim 5 wherein each said circuit has a unique baseline frequency response.

8. A damage locating system as in claim 5 wherein, for each said circuit, each of said capacitors is electrically connected in parallel to an adjoining one of said inductors to define an adjoining capacitor-inductor pair, and wherein said baseline frequency response comprises a band of frequencies with a unique portion of said band corresponding to one of said adjoining capacitor-inductor pairs.

9. A damage locating system as in claim 5 wherein said substrate material is flexible.

10. A damage locating system providing thermal protection, comprising:

a flexible, non-conductive substrate material;

at least one electrical circuit deposited as a reflective-surface, thin-film trace on said substrate material to substantially tile an area of interest thereon, each said circuit defined by an alternating arrangement of capacitors and inductors connected in parallel, each of said capacitors being an interdigitated-electrodes capacitor and each of said inductors being a spiral inductor; and

a magnetic field response recorder for interrogating each said circuit prior to damage thereof to establish a baseline frequency response for each said circuit, and for interrogating each said circuit after damage thereto wherein changes from said baseline frequency response for any said circuit are indicative of damage thereto and a corresponding location thereof.

11. A damage locating system as in claim 10 wherein each said circuit has a unique baseline frequency response.

12. A damage locating system as in claim 10 wherein, for each said circuit, each of said capacitors is electrically connected in parallel to an adjoining one of said inductors to define an adjoining capacitor-inductor pair, and wherein said baseline frequency response comprises a band of frequencies with a unique portion of said band corresponding to one of said adjoining capacitor-inductor pairs.

13. A damage locating system providing thermal protection, comprising:

an array of sensors substantially tiling an area of interest, each of said sensors defined by operatively coupled capacitance and inductance, each of said sensors being a reflective-surface conductor; and

a magnetic field response recorder for interrogating each of said sensors prior to damage thereof to establish a baseline frequency response for each of said sensors, and for interrogating each of said sensors after damage thereto wherein changes from said baseline frequency response for any of said sensors are indicative of damage thereto and a corresponding location thereof.

14. A damage locating system as in claim 13 wherein each of said sensors is fabricated as a thin film.

15. A damage locating system as in claim 13 wherein each of said sensors comprises an interdigitated-electrode capacitor electrically coupled to a spiral inductor.

16. A damage locating system as in claim 13 wherein each of said sensors comprises an open-circuit spiral trace sensor having inductance and capacitance that allows said magnetic field response recorder to detect said baseline frequency response as well as any changes thereto.