COMPOSITE STRUCTURE

• US 20100068450A1
• Filed: 11/26/2007
• Published: 03/18/2010
• Est. Priority Date: 12/04/2006
• Status: Active Grant

• Current Assignee: Airbus Operations Limited (Airbus SE)
• Original Assignee: Airbus UK Limited (Airbus SE)
• Inventors: Lloyd, James
• Granted Patent: US 8,283,018 B2
• Time in Patent Office: Days
• US Class Current: 428/99
• CPC Class Codes: B32B 3/02 characterised by features of form at particular places, e.g. in edge regions non-uniform thickness B32B3/263
• CPC Class Codes: B64C 1/12 Construction or attachment of skin panels
• CPC Class Codes: B64C 3/24 Moulded or cast structures
• CPC Class Codes: B64C 3/26 Construction, shape, or attachment of separate skins, e.g. panels
• CPC Class Codes: Y10T 156/10 Methods of surface bonding and/or assembly therefor
• CPC Class Codes: Y10T 428/24008 including fastener for attaching to external surface
• CPC Class Codes: Y10T 428/24479 including variation in thickness
• CPC Class Codes: Y10T 428/24612 Composite web or sheet

Abstract

A composite structure comprising: a panel formed from two or more plies of composite material, the panel having a surface formed with a step where the thickness of the panel changes. Two or more stiffeners are attached to the surface of the panel. One of the stiffeners engages at least part of the step so as to transmit load forces in the panel.

Claims

1. A composite structure comprising:

a panel formed from two or more plies of composite material, the panel having a surface formed with a step where the thickness of the panel changes; and

two or more stiffeners attached to the surface of the panel;

wherein one of the stiffeners engages at least part of the step.

2. The composite structure of claim 1 further comprising a cap attached to the surface of the panel on a thicker side of the step and attached to one of the stiffeners on a thinner side of the step.

3. The composite structure of claim 2 wherein the cap is formed from one or more plies of composite material.

4. The composite structure of claim 1 wherein the stiffener which engages at least part of the step comprises a stiffening portion which extends away from the panel, and a foot which is attached to the surface of the panel on a thinner side of the step and extends away from the stiffening portion to a toe remote from the stiffening portion, wherein the toe engages at least part of the step.

5. The composite structure of claim 1 wherein the stiffener which engages at least part of the step comprises a stiffening portion which extends away from the panel and engages at least part of the step.

6. The composite structure of claim 5 wherein an adjacent stiffener comprises a stiffening portion which extends away from the panel, and wherein said stiffening portions are at least partially formed from the same layer.

7. The composite structure of claim 1 wherein the stiffener which engages at least part of the step comprises a first part which is attached to the surface of the panel on a thicker side of the step;

and a second part which is attached to the surface of the panel on a thinner side of the step whereby the stringer straddles the step.

8. The composite structure of claim 1 wherein the step is formed by the edges of one or more discontinued plies in the panel.

9. The composite structure of claim 1 wherein the step is formed by the edges of one or more discontinued plies, and a filler between the one stiffener and the discontinued plies.

10. The composite structure of claim 1 wherein the step extends at an angle of greater than 45°

to the plies in the panel adjacent to the step.

11. The composite structure of claim 1 wherein a ramp is formed in the surface of the panel between an adjacent stiffener and the step.

12. The composite structure of claim 1 wherein a ramp is formed in the surface of the panel, and at least part of one of the stiffeners engages the ramp.

13. The composite structure of claim 1 wherein the stiffeners are each formed from two or more plies of composite material.

14. The composite structure of claim 1 further comprising fasteners passing through the stiffeners and the panel.

15. A method of manufacturing the composite structure of claim 1, the method comprising forming the panel with the step;

attaching the stiffeners to the surface of the panel; and

engaging at least part of the step with one of the stiffeners.

16. The method of claim 15 further comprising forming the step by discontinuing two or more plies in the panel, and machining the ends of the discontinued plies.

17. A method of transmitting load in the composite structure of claim 1, the method comprising transmitting load between the step and the stiffener.