METHOD FOR PRODUCING CONTOURED COMPOSITE STRUCTURES AND STRUCTURES PRODUCED THEREBY

• US 20090261199A1
• Filed: 04/17/2008
• Published: 10/22/2009
• Est. Priority Date: 04/17/2008
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Stickler, Patrick B., Noel, Jennifer S., McCarville, Douglas A., Guzman, Juan C., Sweetin, Joseph L.
• Granted Patent: US 9,090,028 B2
• Time in Patent Office: Days
• US Class Current: 244/117.R
• 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 70/34 and shaping or impregnating by compression , i.e. combined with compressing after the lay-up operation
• CPC Class Codes: B29C 70/38 Automated lay-up, e.g. using robots, laying filaments according to predetermined patterns application heads for tyres B29D30/28
• CPC Class Codes: B29C 70/44 using isostatic pressure, e.g. pressure difference-moulding, vacuum bag-moulding, autoclave-moulding or expanding rubber-moulding
• CPC Class Codes: B29D 99/0007 having a variable cross-section
• CPC Class Codes: B29L 2031/3082 Fuselages
• CPC Class Codes: B30B 5/02 wherein the pressing means is in the form of a flexible element, e.g. diaphragm, urged by fluid pressure
• CPC Class Codes: B32B 37/10 characterised by the pressing technique, e.g. using action of vacuum or fluid pressure
• CPC Class Codes: B32B 37/1018 using only vacuum
• 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

Abstract

A method is provided for forming a composite part contoured along its length and having at least one leg. The method includes forming a stack of fiber reinforced, pre-preg plies by laying down individual segments of unidirectional fibers in each ply. Each of the segments is placed in a preselected orientation related to the contour of the part. The leg is formed by bending a portion of the stack over a tool.

Claims

1. A method of forming a composite part contoured along its length and having at least one leg, comprising:

forming a stack of fiber reinforced, pre-preg plies by laying down individual segments of unidirectional fibers in each ply, including placing each of the segments in a preselected orientation related to the contour of the part; and

,

forming the at least one leg by bending a portion of the stack over a tool.

2. The method of claim 1, wherein:

the segments are tapered, and

placing the segments includes orienting the longitudinal axis of each of the tapered segments generally parallel to a radial coordinate defining the contour of the part.

3. The method of claim 1, wherein forming the stack further includes laying down unidirectional fibers extending generally perpendicular to the direction of the fibers in the individual segments.

4. The method of claim 1, wherein laying down the individual segments is performed by an automatic fiber placement machine.

5. The method of claim 4, wherein forming the stack further includes laying down unidirectional fibers along the length of the part, generally traverse to the fiber orientation of the individual segments.

6. The method of claim 1, wherein bending a portion of the stack over a tool is performed by drape forming.

7. The method of claim 1, further comprising compacting and curing the formed stack.

8. A composite part formed by the method of claim 1.

9. A frame section for an aircraft formed by the method of claim 1.

10. A method of forming a contoured composite frame section, comprising:

forming a flat stack of fiber reinforced, pre-preg plies, including individually placing fiber segments in at least certain of the plies in a preselected polar orientation;

forming a first leg of the frame section; and

,

compacting and curing the formed stack.

11. The method of claim 10, further comprising:

forming a second leg of the frame section by hot drape forming the flat stack over a tool.

12. The method of claim 10, wherein individually placing the fiber segments includes tapering the pattern of the fibers in each of the segments.

13. The method of claim 12, wherein individually placing the fiber segments is performed using an automatic fiber placement machine.

14. The method of claim 10, wherein individually placing the fiber segments is performed by placing fiber tape wedges in side-by-side relationship to each other.

15. The method of claim 10, further comprising:

laying down a pattern of unidirectional fibers in other of the plies that extend generally traverse to the orientation of the fiber segments.

16. The method of claim 10 wherein forming the first leg of the frame section is performed by bending the stack along a first edge of the stack.

17. The method of claim 16, further comprising:

forming a second leg of the frame section by bending the stack along a second edge of the stack.

18. The method of claim 16, wherein bending the stack along the first edge is performed by vacuum forming the stack over a tool.

19. The method of claim 17, wherein bending the stack along the second edge is performed by hot drape forming.

20. A composite frame section for a vehicle formed by the method of claim 10.

21. A method of fabricating a curved composite frame section having a cross section including at least one leg extending along the length of the frame section, comprising:

forming stack of fiber reinforced pre-preg plies using an automatic fiber placement machine, including laying down segments of unidirectional fibers having axes of orientation generally aligned with a radial coordinate defining the curvature of the frame section, and laying down courses of unidirectional fibers along the length of the frame section;

forming the at least one leg along an edge of the stack by vacuum forming the stack on a tool; and

,

compacting and curing the vacuum formed stack.

22. The method of claim 21, wherein laying down the segments of unidirectional fibers is performed by placing the segments in side-by-side relationship along a length of the stack.

23. The method of claim 21, wherein laying down the courses of unidirectional fibers along the length of the frame section includes moving the automatic fiber placement machine along a curved path generally matching the curvature of the frame section.

24. The method of claim 21, further comprising:

forming a plurality of spaced apart cutouts along the edge of the stack.

25. A method of fabricating a multi-leg curved composite frame section for an aircraft, comprising:

forming a frame section by

using an automatic fiber placement machine to form a flat stack of composite plies, including forming at least certain of the plies by automatically placing segments of pre-preg unidirectional fibers in side-by-side relationship along the length of the stack in which the axial orientation of the fibers in the segments is generally aligned with radial coordinates defining the curvature of the frame section, and forming other of the plies by automatically placing pre-preg unidirectional fibers along the length of the stack in which the axial orientation of the fibers is traverse to the axial orientation of the fibers in the segments,

forming spaced apart cut-outs in the flat stack along a first edge of the flat stack,

forming a first leg of the frame section by using drape forming to bend a second edge of the flat stack over a tool,

forming a second leg of the frame section by using hot drape forming to bend the first edge of the flat stack over a tool;

placing the frame section on a tool;

installing an intensifier and a caul plate on the frame section;

vacuum bagging the frame section and the tool; and

,

consolidating and curing the frame section in an autoclave.