Method of mapping anomalies in homogenous material

• US 9,329,153 B2
• Filed: 03/12/2013
• Issued: 05/03/2016
• Est. Priority Date: 01/02/2013
• Status: Active Grant

• Current Assignee: United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration
• Original Assignee: United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration
• Inventors: Woodard, Stanley E., Taylor, Bryant D.
• Primary Examiner(s): Vazquez, Arleen M
• Assistant Examiner(s): Alejnikov, Jr., Robert P
• Application Number:
  US13/796,626
• Publication Number:
  US 20150260685A1
• Time in Patent Office: 1,148 Days
• Field of Search: 324237-244, 324/345, 235/493, 235/449, 235/451, 235/492, 340/572.7, 340/572.1
• US Class Current: 1/1
• CPC Class Codes: G01N 27/82 for investigating the presence of flaws

Abstract

An electrical conductor and antenna are positioned in a fixed relationship to one another. Relative lateral movement is generated between the electrical conductor and a homogenous material while maintaining the electrical conductor at a fixed distance from the homogenous material. The antenna supplies a time-varying magnetic field that causes the electrical conductor to resonate and generate harmonic electric and magnetic field responses. Disruptions in at least one of the electric and magnetic field responses during this lateral movement are indicative of a lateral location of a subsurface anomaly. Next, relative out-of-plane movement is generated between the electrical conductor and the homogenous material in the vicinity of the anomaly'"'"'s lateral location. Disruptions in at least one of the electric and magnetic field responses during this out-of-plane movement are indicative of a depth location of the subsurface anomaly. A recording of the disruptions provides a mapping of the anomaly.

Claims

1. A method of mapping anomalies in a homogenous material, comprising the steps of:

providing an electrical conductor having first and second ends and shaped between said first and second ends for storage of an electric field and a magnetic field, said first and second ends remaining electrically unconnected such that said electrical conductor is maintained as an unconnected single-component open-circuit having inductance and capacitance wherein, in the presence of a time-varying magnetic field, said electrical conductor resonates to generate harmonic electric and magnetic field responses, each of which has a frequency, amplitude and bandwidth associated therewith;

providing a magnetic field response recorder having an antenna for wirelessly transmitting said time-varying magnetic field to said electrical conductor and for wirelessly detecting said frequency, amplitude and bandwidth associated with at least one of said electric and magnetic field responses;

positioning said electrical conductor and said antenna in a fixed relationship to one another;

establishing, at a calibration time, baseline electric and magnetic field responses for a homogeneous material known to be free of anomalies;

generating, at an inspection time that is subsequent to said calibration time, relative lateral movement between said electrical conductor and the homogenous material while maintaining said electrical conductor at a fixed distance from the homogenous material, wherein changes between at least one of said electric and magnetic field responses during said lateral movement and said baseline electric and magnetic field responses are indicative of a lateral location of an anomaly in the homogenous material at a region thereof;

generating, at said inspection time, relative out-of-plane movement between said electrical conductor and the homogenous material in the vicinity of said lateral location wherein changes between at least one of said electric and magnetic field responses during said out-of-plane movement and said baseline electric and magnetic field responses are indicative of a depth location of the anomaly in the homogenous material; and

recording said changes during said lateral movement and said changes during said out-of-plane movement wherein the anomaly is mapped thereby.

2. A method according to claim 1, wherein said electrical conductor and a surface of the homogenous material remain substantially parallel to one another during said lateral movement.

3. A method according to claim 1, wherein said out-of-plane movement is substantially perpendicular to a surface of the homogenous material.

4. A method according to claim 1, wherein said lateral movement is generated by moving only said electrical conductor and said antenna.

5. A method according to claim 1, wherein said out-of-plane movement is generated by moving only said electrical conductor and said antenna.

6. A method according to claim 1, wherein said lateral movement is generated by moving only the homogenous material.

7. A method according to claim 1, wherein said out-of-plane movement is generated by moving only the homogenous material.

8. A method of mapping anomalies in a homogenous material, comprising the steps of:

providing an electrical conductor having first and second ends and shaped to form a spiral between said first and second ends for storage of an electric field and a magnetic field, said spiral lying in a plane, said first and second ends remaining electrically unconnected such that said electrical conductor is maintained as an unconnected single-component open-circuit having inductance and capacitance wherein, in the presence of a time-varying magnetic field, said electrical conductor resonates to generate harmonic electric and magnetic field responses, each of which has a frequency, amplitude and bandwidth associated therewith;

providing a magnetic field response recorder having an antenna for wirelessly transmitting said time-varying magnetic field to said electrical conductor and for wirelessly detecting said frequency, amplitude and bandwidth associated with at least one of said electric and magnetic field responses;

positioning said electrical conductor and said antenna in a fixed spaced-apart relationship to one another;

establishing, at a calibration time, baseline electric and magnetic field responses for a homogeneous material known to be free of anomalies;

generating, at an inspection time that is subsequent to said calibration time, relative lateral movement between said electrical conductor and a surface of the homogenous material while maintaining said electrical conductor at a fixed distance from the surface of the homogenous material, wherein changes between at least one of said electric and magnetic field responses during said lateral movement and said baseline electric and magnetic field responses are indicative of a lateral location of an anomaly in the homogenous material at a region thereof;

generating, at said inspection time, relative out-of-plane movement between said electrical conductor and the homogenous material in the vicinity of said lateral location wherein changes between at least one of said electric and magnetic field responses during said out-of-plane movement and said baseline electric and magnetic field responses are indicative of a depth location of the anomaly in the homogenous material; and

recording said changes during said lateral movement and said changes during said out-of-plane movement wherein the anomaly is mapped thereby.

9. A method according to claim 8, wherein said electrical conductor and the surface of the homogenous material remain substantially parallel to one another during said lateral movement.

10. A method according to claim 8, wherein said out-of-plane movement is substantially perpendicular to the surface of the homogenous material.

11. A method according to claim 8, wherein said lateral movement is generated by moving only said electrical conductor and said antenna.

12. A method according to claim 8, wherein said out-of-plane movement is generated by moving only said electrical conductor and said antenna.

13. A method according to claim 8, wherein said lateral movement is generated by moving only the homogenous material.

14. A method according to claim 8, wherein said out-of-plane movement is generated by moving only the homogenous material.

15. A method of mapping anomalies in a homogenous material, comprising the steps of:

providing an antenna in a fixed spaced-apart relationship with an electrical conductor, said electrical conductor having first and second ends and shaped to form a spiral between said first and second ends for storage of an electric field and a magnetic field, said first and second ends remaining electrically unconnected such that said electrical conductor is maintained as an unconnected single-component open-circuit having inductance and capacitance;

coupling a magnetic field response recorder to said antenna;

establishing, at a calibration time, baseline electric and magnetic field responses for a homogeneous material known to be free of anomalies;

operating said magnetic field response recorder such that (i) said antenna wirelessly transmits a time-varying magnetic field to said electrical conductor wherein, in the presence of said time-varying magnetic field, said electrical conductor resonates to generate harmonic electric and magnetic field responses, each of which has a frequency, amplitude and bandwidth associated therewith, and (ii) said antenna wirelessly detects said frequency, amplitude and bandwidth associated with at least one of said electric and magnetic field responses;

generating, at an inspection time that is subsequent to said calibration time, relative lateral movement between said electrical conductor and the homogenous material while maintaining said electrical conductor at a fixed distance from the homogenous material, wherein changes between at least one of said electric and magnetic field responses during said lateral movement and said baseline electric and magnetic field responses are indicative of a lateral location of an anomaly in the homogenous material at a region thereof;

generating relative out-of-plane movement between said electrical conductor and the homogenous material in the vicinity of said lateral location wherein changes between at least one of said electric and magnetic field responses during said out-of-pane movement and said baseline electric and magnetic field responses are indicative of a depth location of the anomaly in the homogenous material; and

recording said changes during said lateral movement and said changes during said out-of-plane movement wherein the anomaly is mapped thereby.

16. A method according to claim 15, wherein said electrical conductor and a surface of the homogenous material remain substantially parallel to one another during said lateral movement.

17. A method according to claim 15, wherein said out-of-plane movement is substantially perpendicular to the surface of the homogenous material.

18. A method according to claim 15, wherein said lateral movement is generated by moving only said electrical conductor and said antenna.

19. A method according to claim 15, wherein said out-of-plane movement is generated by moving only said electrical conductor and said antenna.

20. A method according to claim 15, wherein said lateral movement is generated by moving only the homogenous material.

21. A method according to claim 15, wherein said out-of-plane movement is generated by moving only the homogenous material.