Electrical circuit assemblies and structural components incorporating same

• US 8,534,133 B2
• Filed: 07/07/2009
• Issued: 09/17/2013
• Est. Priority Date: 07/08/2008
• Status: Active Grant

• Current Assignee: BAE Systems Plc
• Original Assignee: BAE Systems Plc
• Inventors: Hucker, Martyn John, Haq, Sajad, Dunleavy, Michael, Gough, David William, Rew, Jason Karl, Webberley, Philip Lawrence
• Primary Examiner(s): Noori, Max
• Application Number:
  US13/003,145
• Publication Number:
  US 20110107843A1
• Time in Patent Office: 1,533 Days
• Field of Search: 737/60, 737/77
• US Class Current: 73/777
• CPC Class Codes: B29C 70/10 characterised by the structure of fibrous reinforcements , e.g. hollow fibres
• CPC Class Codes: B29C 70/882 partly or totally electrically conductive, e.g. for EMI shielding conductive floors or floor coverings H05F3/025; EMI shielding in general H05K9/00
• CPC Class Codes: B29C 70/885 with incorporated metallic wires, nets, films or plates as lost heating elements B29C35/0272, B29C61/0625
• CPC Class Codes: G01M 5/0016 of aircraft wings or blades
• CPC Class Codes: G01M 5/0041 by determining deflection or stress
• CPC Class Codes: G01M 5/0083 by measuring variation of impedance, e.g. resistance, capacitance, induction
• CPC Class Codes: H01B 5/14 comprising conductive layers or films on insulating-supports
• CPC Class Codes: H01Q 1/28 Adaptation for use in or on aircraft, missiles, satellites, or balloons

Abstract

A structural health monitoring arrangement includes a component formed of fiber reinforced composite material with a plurality of electrical conducting fibers intrinsic to the composite defining electrical paths that run through the composite. The paths act as sensing paths running through the material and a detector watches for changes in electrical property indicative of a structural event. The paths may be configured as an open or a closed node grid whose electrical continuity is monitored directly or indirectly. Alternatively they may be fibers having a piezoresistive property and the changes in resistance may be monitored.

Claims

1. A structural health monitoring arrangement comprising:

a component formed of a fibre reinforced composite material including a plurality of electrically conducting continuous fibres defining electrical paths running through said composite material; and

a detector for monitoring an electrical characteristic of one or more of said paths, to determine a structural condition of said component;

wherein said paths are arranged in groups in respective coordinate directions; and

the electrical paths are not in electrical contact at nodes of said coordinate directions, to provide an open node network.

2. A structural health monitoring arrangement according to claim 1, wherein said electrically conducting fibres are reinforcing fibres.

3. A structural health monitoring arrangement according to claim 1, wherein said groups extend in orthogonal linear directions in a two-dimensional array to allow detection in X and Y dimensions.

4. A structural health monitoring arrangement according to claim 3, wherein said groups are layered for detection in a third Z direction.

5. A structural health monitoring arrangement according to claim 1, wherein said detector is configured for detecting continuity of one or more selected paths and for determining the co-ordinates of an event causing a break in continuity of one or more of said paths.

6. A structural health monitoring arrangement according to claim 1, wherein the electrically conducting fibres are selected to be piezoresistive, whereby a resistance of a given fibre varies in accordance with applied strain.

7. A structural health monitoring arrangement according to claim 6, wherein selected paths are spaced from a neutral bending axis of the component, to allow detection of bending of the component.

8. A structural health monitoring arrangement according to claim 7, comprising:

two groups of electrically conducting paths spaced one to either side of the neutral bending axis, the detector being configured for a change of resistance of each group and classifying any loading in terms of a tensile load, a compressive load, bending in a first sense or bending in a second, opposite sense.

9. A structural health monitoring arrangement according to claim 1, wherein said component comprising:

an electrical screening element disposed adjacent at least one external surface of said component.

10. A structural health monitoring arrangement according to claim 2, wherein said paths are arranged in groups in respective co-ordinate directions.

13. A structural health monitoring arrangement according to claim 5, wherein said detector is configured for monitoring at spaced intervals to collect data pertaining to said paths, and for determining when changes in said data exceed a threshold value at one or more locations.

14. A structural health monitoring arrangement according to claim 2, wherein the electrically conducting fibres are selected to be piezoresistive, whereby a resistance of a given fibre varies in accordance with applied strain.

11. A structural health monitoring arrangement, comprising:

a component formed of a fibre reinforced composite material including a plurality of electrically conducting fibres defining electrical paths running through said composite material;

a detector for monitoring an electrical characteristic of one or more of said paths, to determine a structural condition of said component,

wherein the electrically conducting fibres are selected to be piezoresistive, whereby a resistance of a given fibre varies in accordance with applied strain, and

selected paths are spaced from a neutral bending axis of the component, to allow detection of bending of the component; and

two groups of electrically conducting paths spaced one to either side of the neutral bending axis, the detector being configured for a change of resistance of each group and classifying any loading in terms of a tensile load, a compressive load, bending in a first sense or bending in a second, opposite sense.

12. A structural health monitoring arrangement according to claim 11, wherein the electrical paths are in electrical contact at nodes of said co-ordinate directions to provide a closed node network.

15. A structural health monitoring arrangement according to claim 11, wherein the electrical paths are not in electrical contact at nodes of said co-ordinate directions, to provide an open node network.