Hybrid resilient and frangible layered structural health sensor

• US 8,138,773 B2
• Filed: 09/02/2008
• Issued: 03/20/2012
• Est. Priority Date: 09/02/2008
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Fay, Matthew K., Sheffield, Greg L.
• Primary Examiner(s): NATALINI, JEFF WILLIAM
• Application Number:
  US12/202,883
• Publication Number:
  US 20100052704A1
• Time in Patent Office: 1,295 Days
• Field of Search: 324/700
• US Class Current: 324/700
• CPC Class Codes: G01N 17/04 Corrosion probes

Abstract

A sensor for monitoring and testing for both possible fractures and corrosion in structural elements is disclosed. A frangible material layer including a thin breakable conductor sense loop and a resilient material layer including a conductive corrosion sense loop bonded on top of the frangible layer form an assembly which is bonded to a structural element to be tested. Portions of the conductive corrosion sense loop are exposed through weep holes in the resilient material layer. A fracture in the bonded structural element induces a disruption in both the frangible membrane and the thin breakable conductor sense loop and corrosion of the conductive corrosion sense loop changes its electrical properties. Measured electrical property changes of the disrupted conductor sense loop and/or the conductive corrosion sense loop reveal possible damage. Both sensor layers may utilize a single shared wireless communications tag to couple to an electrical measuring device.

Claims

1. An apparatus for sensing structural integrity, comprising:

a frangible non-conductive material layer;

a resilient non-conductive material layer disposed on top of the frangible non-conductive material layer;

a breakable conductor sense loop within the frangible non-conductive material layer; and

a conductive corrosion sense loop within the resilient non-conductive material layer and having a portion exposed through at least one weep hole in the resilient non-conductive material layer;

wherein the frangible non-conductive material is disposed adjacent to a structure surface such that the breakable conductor sense loop is disrupted when a fracture occurs in the structure surface and the exposed portion of the conductive corrosion sense loop corrodes when moisture enters the at least one weep hole to induce a change in an electrical property of the conductive corrosion sense loop and wherein the non-conductive material layers are disposed between the structure surface and a second structure surface in a gasket configuration such that both surfaces of the non-conductive material layers are sealed from moisture.

2. The apparatus of claim 1, wherein a disruption of the breakable conductor sense loop from the fracture in the structure surface and the change in the electrical property of the conductive corrosion sense loop from is sensed through an electrical measuring device coupled to both the breakable conductor sense loop and the conductive corrosion sense loop.

3. The apparatus of claim 2, further comprising a wireless communications tag for coupling the electrical measuring device to both the breakable conductor sense loop and the conductive corrosion sense loop.

4. The apparatus of claim 2, further comprising a wired connecting device for coupling the electrical measuring device to both the breakable conductor sense loop and the conductive corrosion sense loop.

5. The apparatus of claim 1, wherein the breakable conductor sense loop and the structure surface comprise a common material.

6. The apparatus of claim 1, wherein the frangible non-conductive material layer is bonded to the structure surface.

7. The apparatus of claim 1, wherein the resilient non-conductive material layer comprises one or more sealing ribs against the second structure surface.

8. The apparatus of claim 1, wherein the frangible non-conductive material layer comprises two layers sandwiching the breakable conductor sense loop.

9. The apparatus of claim 1, wherein the resilient non-conductive material layer comprises two layers sandwiching the conductive corrosion sense loop.

10. The apparatus of claim 1, wherein at least one of the resilient non-conductive material layer and the frangible non-conductive material layer is self-adhesive.

11. A method for sensing structural integrity, comprising the steps of

disposing a frangible non-conductive material having a breakable conductor sense loop within the frangible non-conductive material adjacent to a structure surface;

disposing a resilient non-conductive material layer on top of the frangible non-conductive material layer having a conductive corrosion sense loop within the resilient non-conductive material layer and having a portion of the conductive corrosion sense loop exposed through at least one weep hole in the resilient non-conductive material layer;

sensing a disruption in the breakable conductor sense loop from a fracture in the structure surface; and

sensing a change in an electrical property of the conductive corrosion sense loop from corrosion in the exposed portion of the conductive corrosion sense loop;

wherein the non-conductive material layers are disposed between the structure surface and a second structure surface in a gasket configuration such that both surfaces of the non-conductive material layers are sealed from moisture.

12. The method of claim 11, wherein a disruption of the breakable conductor sense loop from the fracture in the structure surface and the change in the electrical property of the conductive corrosion sense loop from is sensed through an electrical measuring device coupled to both the breakable conductor sense loop and the conductive corrosion sense loop.

13. The method of claim 12, wherein a wireless communications tag couples the electrical measuring device to both the breakable conductor sense loop and the conductive corrosion sense loop.

14. The method of claim 12, wherein a wired connecting device couples the electrical measuring device to both the breakable conductor sense loop and the conductive corrosion sense loop.

15. The method of claim 11, wherein the breakable conductor sense loop and the structure surface comprise a common material.

16. The method of claim 11, wherein the frangible non-conductive material layer is bonded to the structure surface.

17. The method of claim 11, wherein the resilient non-conductive material layer comprises one or more sealing ribs against the second structure surface.

18. The method of claim 11, wherein the frangible non-conductive material layer comprises two layers sandwiching the breakable conductor sense loop.

19. The method of claim 11, wherein the resilient non-conductive material layer comprises two layers sandwiching the conductive corrosion sense loop.

20. The method of claim 11, wherein at least one of the resilient non-conductive material layer and the frangible non-conductive material layer is self-adhesive.