Claims
- 1. A test circuit comprising:
two parallel rows of aligned sense elements for scanning across a material under test surface; at least one linear conductor segment positioned parallel to and between the sensing element rows for imposing a magnetic field; and a right row of sensing elements for detecting a flaw on the right side of a feature and a left row of sensing elements for detecting cracks on the left side of a feature.
- 2. A test circuit as described in claim 1 where the feature is a fastener in an aircraft skin.
- 3. A test circuit as described in claim 1 where the flaw is a crack.
- 4. A test circuit as described in claim 1 where the flaw is corrosion.
- 5. A test circuit as described in claim 1 where the flaw is a buried inclusion.
- 6. A test circuit as described in claim 1 where multiple frequencies are used to remove the interference caused by the feature and isolate the response from the flaw.
- 7. A test circuit as described in claim 1 where a shape filter is used to search the sensor response for shapes that are most likely to be flaws and to suppress responses unlikely to be flaws.
- 8. A test circuit as described in claim 7 where the response from sensing elements on opposite sides of the central conductor are combined to construct a filter representing the flaw of interest, the filter then is used to search the response image for indications likely to be the flaw of interest.
- 9. A test circuit as claimed in claim 8 where the flaw of interest is a crack.
- 10. A test circuit as claimed in claim 8 where the flaw of interest is a buried inclusion.
- 11. A test circuit as claimed in claim 1 further comprising the primary winding and sense elements are in the same plane.
- 12. A test circuit as claimed in claim 1 further comprising the primary winding and sense elements are in the different planes.
- 13. A test circuit as claimed in claim 1 further comprising that each individual sense element in one row of sense elements is aligned with a sense element in the second row of sense elements in a direction perpendicular to the extended portions of the primary winding.
- 14. A test circuit as claimed in claim 1 further comprising that the sense elements in one row of sense elements is offset in a direction parallel to the extended portions of the primary winding from the sense elements in the second row of sense elements.
- 15. A test circuit as claimed in claim 14 wherein the offset distance is one-half of the length of a sensing element.
- 16. A test circuit as claimed in claim 1 wherein the location of the sense elements is non-uniform in the direction parallel to the extended portions of the primary winding.
- 17. A test circuit as claimed in claim 1 wherein the primary winding and sense elements are fabricated onto a flexible substrate.
- 18. A test circuit as claimed in claim 1 wherein the primary winding and sense elements are fabricated onto a rigid substrate.
- 19. A test circuit as claimed in claim 1 wherein at least one of the sense elements includes a magnetoresistive sensor.
- 20. A test circuit as claimed in claim 1 wherein at least one of the sense elements includes a giant magnetoresistive sensor.
- 21. A test circuit in claim 20 further comprising a secondary coil that surrounds the giant magnetoresistive sensing elements.
- 22. A test circuit as claimed in claim 21 wherein the secondary coil is in a feedback configuration.
- 23. A method for inspecting materials comprising:
disposing at least two parallel rows of aligned sense elements on substrate for scanning across a material under test surface, with at least one linear drive conductor segment positioned parallel to and between the sensing element rows for imposing a magnetic field; and having a right row of sensing elements for detecting a flaw on the right side of a feature and a left row of sensing elements for detecting cracks on the left side of a feature; passing a time-varying electric current through the drive conductor; measuring the response from each of the sense elements, comprising the scan responses to a shape filter representing the response from a flaw, and searching the scan responses for indications likely to be the flaw.
- 24. A test circuit as described in claim 23 where multiple frequencies are used to remove the interference caused by the feature and isolate the response from the flaw.
- 25. A test circuit as described in claim 23 where the feature is a fastener in an aircraft skin.
- 26. A test circuit as described in claim 23 where the flaw is a crack.
- 27. A test circuit as described in claim 23 where the flaw is a buried inclusion.
RELATED APPLICATIONS
[0001] This application is a continuation-in-part of U.S. Application No. 10/102,620, filed Mar. 19, 2002, which claims the benefit of U.S. Provisional Application No. 60/276,997, filed Mar. 19, 2001. This application also claims the benefit of U.S. Provisional Application No. 60/349,104, filed Jan. 16, 2002. The entire teachings of the above applications are incorporated herein by reference.
Provisional Applications (2)
|
Number |
Date |
Country |
|
60276997 |
Mar 2001 |
US |
|
60349104 |
Jan 2002 |
US |
Continuation in Parts (1)
|
Number |
Date |
Country |
Parent |
10102620 |
Mar 2002 |
US |
Child |
10345883 |
Jan 2003 |
US |