Method for producing an electrically and/or thermally conductive part from a composite material and resulting part

Patent metadata

Field	Value
Publication number	US-9895833-B2
Application number	US-201113820757-A
Country	US
Kind code	B2
Filing date	Sep 7, 2011
Priority date	Sep 7, 2010
Publication date	Feb 20, 2018
Grant date	Feb 20, 2018

Abstract

In order to produce a part ( 16 ) from a composite material, which is conductive at least on one of the surfaces thereof, the method consists of: the conductive overstitching ( 30 ) of a preform ( 20 ) of the part using electrically or thermally conductive threads ( 31, 32 ) with substantially parallel stitch lines ( 34 ) oriented in at least two intersecting directions. The parts obtained are adapted for the production of aircraft structures that may be subjected to lightning strikes and allow return currents from the electrical or electronic aircraft equipment and/or the discharge of heat by conduction.

First claim

The invention claimed is:

1. A part ( 10 ), comprising:
a composite material comprising fibers made of a material having an electrical resistivity equal or greater than 1.5×10^ −6 Ω·m embedded in a polymerized organic matrix, the fibers arranged in plies ( 21 ) superimposed within a thickness E of the part between an upper face ( 11 ) of the part and a lower face ( 12 ) of the part; and
an electrically conductive overstitching ( 30 ), including a plurality of sewing lines ( 34 ), each of said sewing lines comprising an upper thread ( 31 ) on an upper face ( 11 ) side and a lower thread ( 32 ) on a lower face ( 12 ) side, said upper threads ( 31 ) and said lower threads ( 32 ) intersecting at stitches ( 33 ) of said upper threads ( 31 ) and said lower threads ( 32 ), and said upper threads ( 31 ) and said lower threads ( 32 ) crossing all or a part of the plies ( 21 ) at locations of said stitches ( 33 ),
at least two of the plurality of sewing lines having a first orientation on, respectively, the upper face ( 11 ) of the part ( 10 ), and the lower face ( 12 ) of the part ( 10 ), and at least two of the plurality of sewing lines having a second orientation, different from the first orientation, on, respectively, the upper face ( 11 ) of the part ( 10 ) and the lower face ( 12 ) of the part ( 10 ), and
wherein any of the upper threads ( 31 ) and the lower threads ( 32 ) are electrically conductive and form, respectively on the upper face ( 11 ) and the lower face ( 12 ), electrically conductive lines, said electrically conductive lines determining a surface network in which the electrically conductive threads are in electrical contact where two electrically conducting lines of different directions overlap on a surface of the part.

2. The part according to claim 1 , wherein only one of the upper threads ( 31 ) or the lower threads ( 32 ) are electrically conductive, said electrically conductive threads crossing only a part of the thickness E of the part ( 10 ) at the stitches ( 33 ).

3. The part according to claim 1 , wherein the electrically conductive threads ( 31 , 32 ) are metallic threads formed by an assembly of a plurality of strands.

4. The part according to claim 1 , wherein the electrically conductive threads ( 31 , 32 ) have conductive cross-sections ranging between 0.05 mm 2 and 0.50 mm 2 and include between 1 and 50 strands.

5. The part according to claim 1 , wherein distances D between neighboring sewing lines ( 34 ) determine on the considered face of the part ( 10 ), a surface metallization density having a value in a range of 30 to 500 g/m 2 .

6. The part according to claim 1 , wherein a density of stitches ( 33 ) of the electrically conductive overstitching ( 30 ) on the surface of the part ( 10 ) ranges locally between 2500 and 250000 stitches per m 2 .

7. The part according to claim 1 , wherein a surface density of electrically conductive threads and/or a density of stitches ( 33 ) of the electrically conductive overstitching ( 30 ) is different according to the sites on the surface of the part ( 10 ).

8. The part according to claim 7 , wherein the surface density of electrically conductive threads and/or the density of stitches ( 33 ) of the electrically conductive overstitching ( 30 ) is increased in areas ( 13 ) corresponding to fitting surfaces between the part ( 10 ) and one or more other electrically conductive parts ( 10 a ).

9. The part according to claim 1 , wherein the part is configured to be included as part of an aircraft structure, at least one face of the part having electrically conductive overstitching threads that form a metallization that ensures current return for electric or electronic components of the aircraft.

10. The part according to claim 1 , wherein the part is configured to be included as part of an aircraft structure, at least one face of the part having electrically conductive overstitching threads that form a metallization that protects the part against effects of a lightning strike.

11. The part according to claim 3 , wherein the electrically conductive threads ( 31 , 32 ) contain copper, aluminum or a steel.

12. The part according to claim 1 , wherein a metallization is carried out by means of electrically conductive overstitching threads on a first face of said part, the said threads crossing only partially the thickness of said part, wherein a metallization is carried out by means of electrically conductive overstitching threads on a second face of said part, the threads crossing only partially the a thickness of said part, the overstitching threads on the first face being electrically isolated from the overstitching threads of the second face by plies without electrically conductive threads.

13. An assembly, comprising:
a first part ( 10 ) according to claim 1 ; and
a second part ( 10 a ),
wherein said first part is metallized on the upper face ( 11 ) with the electrically overstitching upper threads ( 31 ),
wherein said second part is in contact with a contact area ( 13 ) of the lower face ( 12 ) of the first part ( 10 ), and
wherein, at least in the contact area ( 13 ), the overstitching lower threads ( 32 ) are electrically conductive, to ensure an electrical continuity between the upper face and the second face in the contact area ( 13 ).

14. The assembly according to claim 13 , wherein a separation distances between the sewing lines is reduced and/or a distance P separating the successive stitches is reduced, in the contact area ( 13 ).

Assignees

• Cinquin Jacques
• Airbus Group Sas

Inventors

• Cinquin Jacques

Classifications

• B64C1/12

  Construction or attachment of skin panels · CPC title

• B64D45/02

  Lightning protectors; Static dischargers · CPC title

• Y10T428/24033

  including stitching and discrete fastener[s], coating or bond · CPC title

• B29C70/228 Primary

  the structure being stacked in parallel layers with fibres of adjacent layers crossing at substantial angles · CPC title

• B29K2995/0013

  Conductive · CPC title