Lightning strike protection method and apparatus

• US 7,525,785 B2
• Filed: 12/14/2006
• Issued: 04/28/2009
• Est. Priority Date: 12/14/2006
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Rawlings, Diane C.
• Primary Examiner(s): Jackson; Stephen W
• Assistant Examiner(s): CLARK, CHRISTOPHER JAY
• Application Number:
  US11/611,023
• Publication Number:
  US 20080144249A1
• Time in Patent Office: 866 Days
• Field of Search: 361/218, 361/216, 361/217
• US Class Current: 361/216
• CPC Class Codes: B64D 45/02 Lightning protectors; Static dischargers in general H01T
• CPC Class Codes: H02G 13/00 Installations of lightning conductors; Fastening thereof to supporting structure
• CPC Class Codes: H02G 13/80 Discharge by conduction or dissipation, e.g. rods, arresters, spark gaps
• CPC Class Codes: Y10T 29/301 Method

Abstract

A method and apparatus for implementing a return current network that is external to a composite structure, which directs a current along a known path to the aircraft grounding system using appliqués. The appliqués have a dielectric polymer to isolate the return current from the structure, and a metal foil for conducting the current

Claims

1. An external current return network for lightning strike protection comprising:

a composite structural panel;

a first appliqué

coating on an external surface of the composite structural panel including a first conductive foil and a first dielectric layer;

a second appliqué

coating on said first appliqué

coating, said second appliqué

coating including a second conductive foil and a second dielectric layer; and

electrical connect means coupling said first conductive foil to said second conductive foil;

wherein the first appliqué

coating is oriented such that the first dielectric layer is between the first foil layer and the composite structural panel, and the second appliqué

coating is oriented such that the second dielectric layer is between the second foil layer and the composite structural panel; and

further wherein the electrical connect means is electrically isolated from the composite structural panel.

2. The current return network of claim 1, wherein the first and second conductive foils comprise aluminum.

3. The current return network of claim 1, wherein the first and second dielectric layers comprise a polymer.

4. The current return network of claim 1, further comprising at least one electrically non-conductive region replacing a predetermined area of the second appliqué

coating.

5. The current return network of claim 1, further comprising a first adhesive to bond the first coating to a surface of the structural panel.

6. The current return network of claim 1, wherein the electrical connect means comprises at least one of a fuzz button, a HOLE-type connection and a conductive adhesive.

7. The current return network of claim 1, wherein the first dielectric layer provides electrical isolation between said first conductive foil and a surface of the structural panel.

8. A method of forming an external current return network for lightning strike protection, the method comprising the steps of:

applying a first appliqué

coating on an external surface of a composite structural panel, the first appliqué

coating including a first conductive foil and a first dielectric layer;

applying a second appliqué

coating on the first appliqué

coating, the second appliqué

coating including a second conductive foil and a second dielectric layer; and

electrically connecting the first and second conductive foils with an electrical connecting means;

wherein the first appliqué

coating is oriented such that the first dielectric layer is between the first foil layer and the composite structural panel, and the second appliqué

coating is oriented such that the second dielectric layer is between the second foil layer and the composite structural panel; and

further wherein the electrical connect means is electrically isolated from the composite structural panel.

9. The method of claim 8, wherein connecting the first and second appliqué

coatings forms an electrically contiguous current return structure that is exterior to the composite structural panel.

10. The method of claim 8, wherein the connecting means comprises at least one of a fuzz button, a HOLE-type connection and a conductive adhesive.

11. The method of claim 8, wherein the first and second conductive foils comprise aluminum.

12. The method of claim 8, wherein the first and second dielectric layers comprise a polymer.

13. The method of claim 8, further comprising the step of forming at least one electrically non-conductive region in a predetermined area of the second appliqué

coating.