Curved structural part made of composite material and a process for manufacturing such a part

• US 20100136293A1
• Filed: 11/19/2009
• Published: 06/03/2010
• Est. Priority Date: 11/21/2008
• Status: Active Grant

• Current Assignee: Airbus Operations (European Aeronautic Defence and Space Company EADS NV)
• Original Assignee: Airbus Operations (European Aeronautic Defence and Space Company EADS NV)
• Inventors: Kubryk, Vanessa, Hellard-Lambic, Nathalie
• Granted Patent: US 8,709,576 B2
• Time in Patent Office: Days
• US Class Current: 428/156
• CPC Class Codes: B29C 70/202 arranged in parallel planes or structures of fibres crossing at substantial angles, e.g. cross-moulding compound [XMC] B29C70/207 takes precedence
• CPC Class Codes: B29C 70/302 Details of the edges of fibre composites, e.g. edge finishing or means to avoid delamination
• CPC Class Codes: B29C 70/342 using isostatic pressure
• CPC Class Codes: B29C 70/42 for producing articles of definite length, i.e. discrete articles
• CPC Class Codes: B29D 99/0007 having a variable cross-section
• CPC Class Codes: B29L 2031/003 having a profiled transverse cross-section
• CPC Class Codes: B29L 2031/3082 Fuselages
• CPC Class Codes: B64C 1/061 Frames
• CPC Class Codes: B64C 2001/0072 from composite materials
• CPC Class Codes: Y02T 50/40 Weight reduction
• CPC Class Codes: Y10T 156/1002 with permanent bending or reshaping or surface deformation of self sustaining lamina
• CPC Class Codes: Y10T 156/1052 with cutting, punching, tearing or severing
• CPC Class Codes: Y10T 156/1084 of continuous or running length bonded web
• CPC Class Codes: Y10T 156/12 Surface bonding means and/or assembly means with cutting, punching, piercing, severing or tearing
• CPC Class Codes: Y10T 428/24058 including grain, strips, or filamentary elements in respective layers or components in angular relation
• CPC Class Codes: Y10T 428/24091 with additional layer[s]
• CPC Class Codes: Y10T 428/24116 Oblique to direction of web
• CPC Class Codes: Y10T 428/2419 Fold at edge
• CPC Class Codes: Y10T 428/24479 including variation in thickness
• CPC Class Codes: Y10T 428/24628 Nonplanar uniform thickness material
• CPC Class Codes: Y10T 428/24645 : with folds in parallel planes

Abstract

The disclosed embodiments concern a curved structural part composed of a composite material with reinforced, continuous fibers whose cross section includes at least two wings, with said fibers extending from one wing to the other, with said structural part having a variation in the width of its section parallel to the local radius of curvature. The structural element that results from assembling the parts in the disclosed embodiments therefore has local widening of the section at the connections between the parts constituting a structural element, such as an aircraft fuselage frame, and widening at the connection with the floor profiles, if such a profile is used to make an aircraft fuselage structure. The disclosed embodiments also concern a process for manufacturing such a part, as well as a device for advantageously implementing such a process.

Claims

1. A curved structural part comprised of a composite material with reinforced, continuous fibers whose cross section includes at least two wings, with said fibers extending from one wing to the other, wherein it includes a variation in the width of its section parallel to the local radius of curvature.

2. The curved structural part of claim 1, wherein the variation in width includes a reduction in the minimum local radius of curvature of the part.

3. The curved structural part of claim 1, further comprising 3 wings whose tracks are located in at least two intersecting planes.

4. The curved structural part of claim 1, further comprising a U-shaped cross section.

5. The curved structural part of claim 1, further comprising a Z-shaped cross section.

6. The curved structural part of claim 1, further comprising continuous reinforced fibers extending over at least two wings oriented in a nominal direction + or −

α

in relation to the curve, with α

being between 30° and

60°

.

7. The curved structural part of claim 6, further comprising continuous reinforced fibers, so-called 90°

, extending over at least two wings oriented parallel to a local radius of curvature.

8. The curved structural part of claim 6, further comprising continuous reinforced fibers, so-called 0°

, oriented perpendicularly to the radius of curvature in at least one of the wings.

9. The curved structural part of claim 1, wherein the variation in section is done gradually along a gradient β

, with β

being between 0.07 and 0.15.

10. The curved structural part of claim 9, further comprising a blending radii between the regular parts and the changing section parts between 300 mm and 1000 mm.

11. The curved structural part of claim 10, wherein the continuous fiber reinforcements extending over at least two wings have, at any point on the curved structural part, an effective orientation in relation to the local curve between +3°

and −

3°

compared to their -nominal orientation (α

).

12. The curved structural part of claim 1, further comprising a reinforcement in the thickness of the core in the area where the core widens.

13. The curved structural part of claim 1, further comprising a multidirectional layer along an angle ±

α

on its exterior faces.

14. A structural element comprising an assembly of at least two structural parts, according to claim 1.

15. A process for manufacturing a curved structural part according to claim 1, comprising:

fabricating a mold of the structural element having at least two faces, with said two faces forming a male mold section between the minimum radius of curvature of the structural element and another radius of curvature belonging to one of the two faces;

preparing a stack of multidirectional fibers consisting of one or more fiber plies oriented in the nominal directions ±

α

or 90°

in relation to the longitudinal direction;

cutting a first multidirectional strip in this stack, with said first multidirectional strip extending longitudinally and in width at least equal to the maximum developed width of the structural element;

applying the first multidirectional strip by pressing it gradually over the mold so as to make it mold to its section and curve

wherein the application of the first multidirectional strip is initiated on the face having the minimum radius of curvature, with the first multidirectional strip then pressed and tightened over the other faces.

16. The process of claim 15, further comprising placing a strip of fibers oriented at 0°

along the local curve over at least one wing prior to the placement of the first multidirectional strip or between the placement of the first and a second multidirectional strip.

17. The process of claim 15, further comprising placing a second multidirectional strip having at least two plies oriented at +α

and −

α

in relation to the longitudinal direction of said first multidirectional strip.

18. The process of claim 17, wherein α

is equal to 30°

.

19. The process of claim 17, wherein α

is equal to 45°

.

20. The process claim 15, further comprising placing a second multidirectional strip having at least two plies oriented at 90°

and at +α

in relation to the longitudinal direction of said first multidirectional strip, followed by the placement of a third multidirectional strip having at least two plies oriented at 90° and

−

α

in relation to the longitudinal direction of said first multidirectional strip.

21. A device for implementing the process of claim 15, comprising means capable of placing strips of fibers over the entire length of a curved structural part, comprised of a composite material with reinforced, continuous fibers whose cross section includes at least two wings, with said fibers extending from one wing to the other, wherein it includes a variation in the width of its section parallel to the local radius of curvature, the device further comprising, and means of placing strips of fibers locally over a determined length oriented at 0°

along the local curve over at least one wing prior to the placement of the first multidirectional strip or between the placement of the first and a second multidirectional strip, on a wing of said structural part having a variation in the radius of curvature along its width.

22. An aircraft having the curved structural element of claim 1.