WO2011015999A1

WO2011015999A1 - Composite components

Info

Publication number: WO2011015999A1
Application number: PCT/IB2010/053534
Authority: WO
Inventors: Avinash Ramsaroop; Krishnan Kanny; Mbali Swana
Original assignee: Mwangi, Festus Maina
Priority date: 2009-08-05
Filing date: 2010-08-04
Publication date: 2011-02-10

Abstract

The invention discloses a composite component, which includes a composite material having at least one region with superior and/or complex reinforcement than at least one other region of the composite material. The component includes a plate-like and/or cylindrical fibre-reinforced structure and/or other shape. The invention also extends to a method of fabricating a composite component, which includes the step of laying fibres in at least one region of a composite material that requires further reinforcement than at least one other region of the composite material.

Description

Composite components FIELD OF INVENTION

The present invention relates to composite components.

More particularly, the present invention relates to composite components such as a plate-like or cylindrical fibre-reinforced composite component and a construction method therefore.

BACKGROUND TO INVENTION

Various composite components are known in the construction and design industries. A stress analysis of a typical plate reveals varying stress distributions. The areas with high stress concentrations require more reinforcement than the rest of the structure. If conventional fibre lay-up techniques were used to fabricate the plate structure, fibres would be laid in the various calculated directions over the entire mould surface. The result is that fibres are placed in regions that do not require extra reinforcement. The fabricated structure has the same strength throughout and the excess fibres increase the cost of the plate structure.

It is an object of the invention to suggest a composite component and a construction method therefore which will assist in overcoming the aforementioned problems. SUMMARY OF INVENTION

According to the invention, a composite component, includes a composite material having at least one region with superior and/or complex reinforcement as at least one other region of the composite material.

Also according to the invention, a method of fabricating a composite component, which includes the step of laying fibres in at least one region of a composite material that requires further reinforcement than at least one other region of the composite material. Yet further according to the invention, an aircraft fuselage made of a composite material having at least one region with superior and/or complex reinforcement as at least one other region of the composite material.

Yet further according to the invention, a method of fabricating an aircraft fuselage, consists of a composite component and includes the step of laying fibres in at least one region of a composite material that requires further reinforcement than at least one other region of the composite material.

The composite component may have a plate-like and/or cylindrical fibre- reinforced structure and/or other shape. The composite component may have varied structural strengths across the geometry, surface and/or thickness of the composite component.

The composite component may include complex-shaped components. The method may include localised reinforcement.

The localised reinforcement may be achieved by manually laying the fibres in the required reinforcement areas in the appropriate directions.

In order to provide extra reinforcement to this area, fibres may be placed with one end (diamond end) fixed and the other end (arrow end) free or floating.

The correct fibre direction may be attained during the infusion process by carefully selecting the infusion and vacuum points.

As the resin flows from the infusion point to the vacuum point, the fibres may follow the flow and may remain in that direction until curing is complete.

The fibres may be placed in the appropriate directions with both ends fixed. The method may include the technique known as stitching. The method may be performed autonomously by means of a robotic manipulator. The manipulator may perform the fibre lay-up in a stand-alone environment, i.e. the entire fibre lay-up of a component can be executed by the robotic manipulator, or the manipulator can be integrated into an existing process, such as weaving. The weaving process may be performed on a loom which consists mainly of two constituents; the warp and the weft.

The warp may be a set of longitudinal fibres through which the weft is woven. Therefore the weft may be the fibre that is being woven.

The loom may weave the fibres according to the general fibre layout of the component, i.e. the fibres will be woven into the directions that are required throughout the part.

The robotic manipulator may then add fibres to the areas that require localised reinforcement while the loom is weaving the general pattern.

Orientation and concentration of the localised reinforcement fibre layout may be accomplished via known embroidery techniques that range from handcrafted embroidery to computerised machine embroidery which is capable of reading digitised files.

The fibre orientation may be

(a) radial (as in the case of the edges of a hole); (b) linear (at preferred angles);

(c) concentric (around holes or protrusions); and/or

(d) any combination thereof.

Fibre concentration in a component may vary from a single layer to multiple layers as may be required or allowed by design. The number of layers may vary through the cross-section, as may be required, in a gradual shift from a region of high stress concentration to another of lower concentration.

The composite material may be two-dimensional such as plate-like structures or three-dimensional such as cylindrical structures.

The cylindrical structure may be a fuselage of an aircraft (aircraft body).

The method of performing the fibre lay-up using the proposed concept may include the steps:

(a) of integrating the robotic manipulator with the filament winding process; and/or

(b) of lay-up of the fibres by means of the integrated loom and robotic manipulator system.

Filament winding may be used to achieve the general fibre lay-up and, during this process, the robotic manipulator may execute the fibre lay-up of the localised reinforced areas of the wing and tail sections.

The cylindrically-shaped fuselage may be unrolled to a two-dimensional plate- like structure.

The loom may weave the general fibre layout of the entire structure while the robotic manipulator would be responsible for the localised reinforcement. Once the process has been completed, the woven fibre layout may then be rolled to form the three-dimensional cylindrically-shaped fuselage.

BRIEF DESCRIPTION OF DRAWINGS

The invention will now be described by way of example with reference to the accompanying schematic drawings. In the drawings there is shown in :

Figure 1 : Plate with four holes loaded by force P; Figure 2: Stress distribution of the plate shown in Figure 1;

Figure 3: Fibre layout using (a) conventional techniques, and, (b)

proposed concept;

Figure 4: Manual placement of fibres with one end fixed and the other end free. Views include (a) top view, (b) side view, and (c) infusion direction;

Figure 5: Manual placement of fibres with both ends fixed;

Figure 6: Illustration of woven structure showing the warp and weft fibres;

Figure 7: Illustration of localised reinforcement fibres in a woven

structure; and

Figure 8: Graphical representation of fibre layout of a cylindrical fuselage as a two-dimensional plate-like structure.

DETAILED DESCRIPTION OF DRAWINGS

Referring to the drawings, a composite component in accordance with the invention is shown.

In Figure 1 a plate with four holes loaded by a force P is shown.

A stress analysis of the plate will reveal varying stress distributions as shown in Figure 2. Therefore areas with high stress concentrations would require more reinforcement than the rest of the structure. If conventional fibre lay-up techniques were used to fabricate this structure, fibres would be laid in the various calculated directions over the entire mould surface. This is shown schematically in Figure 3(a). The result is that fibres will be placed in regions that do not require extra reinforcement. The fabricated structure has the same strength throughout and the excess fibres increase the cost of the part. Using the proposed concept, fibres need not be laid out over the entire mould surface but rather only in the regions that require further reinforcement. Figure 3(b) is a schematic representation of this. Due to the localised reinforcement, fewer fibres would be required and thus the cost of the component will be reduced. Further, the component will have varying strengths across its surface and / or thickness.

Method of applying the concept:

Localised reinforcement may be achieved by manually laying the fibres in the required reinforcement areas in the appropriate directions. To illustrate this aspect, a rectangular area is shown in Figure 4(a). In order to provide extra reinforcement to this area, fibres may be placed with one end (diamond end) fixed and the other end (arrow end) free or floating. This is more distinct when viewed from the side as shown in Figure 4(b). The correct fibre direction may be attained during the infusion process by carefully selecting the infusion and vacuum points as shown in Figure 4(c). As the resin flows from the infusion point to the vacuum point, the fibres will follow the flow and will remain in that direction until curing is complete.

Alternatively, the fibres may be placed in the appropriate directions with both ends fixed as shown in Figure 5. This technique is commonly known as stitching. In this case, the location of the infusion and vacuum points is not critical with regard to achieving correct fibre directions.

Manual lay-up of the fibres is tedious and time-consuming. Therefore the process may be performed autonomously by means of a robotic manipulator. The manipulator can perform the fibre lay-up in a stand-alone environment, that is, the entire fibre lay-up of a component can be executed by the robotic manipulator, or the manipulator can be integrated into an existing process, for example, weaving.

The weaving process may be performed on a loom which consists mainly of two constituents; the warp and the weft. The warp is the set of longitudinal fibres through which the weft is woven. Therefore the weft is the fibre that is being woven. This is illustrated in Figure 6. With regard to the proposed concept, the loom will weave the fibres according to the general fibre layout of the component, that is, the fibres will be woven into the directions that are required throughout the part. The robotic manipulator can then add fibres to the areas that require localised reinforcement, as shown in Figure 7, while the loom is weaving the general pattern. This integrated system may be autonomous, thereby decreasing fibre lay-up time. Orientation and concentration of the localised reinforcement fibre layout may be accomplished via known embroidery techniques that range from handcrafted embroidery to computerised machine embroidery which is capable of reading digitised files.

The fibre orientation may be radial (as in the case of the edges of a hole), linear (at preferred angles), concentric (around holes or protrusions), or any combination thereof. Fibre concentration in a component may vary from a single layer to multiple layers as may be required or allowed by the design. The number of layers may vary through the cross-section, as may be required, in a gradual shift from a region of high stress concentration to another of lower concentration. Three-dimensional and complex-shaped components

The application of the proposed concept only to two-dimensional shapes, such as plate-like structures, has been discussed. The concept can also extend to three-dimensional shapes such as cylindrical structures. The fuselage of an aircraft (aircraft body) is an example of a cylindrically-shaped component. The fuselage has a general fibre layout throughout the structure; however, the areas where the wings and tail pieces attach to need further reinforcement. There are two possible methods for performing the fibre lay- up using the proposed concept. The first involves integrating the robotic manipulator with the filament winding process. Filament winding can be used to achieve the general fibre lay-up and, during this process, the robotic manipulator can execute the fibre lay-up of the localised reinforced areas of the wing and tail sections.

The second method entails the lay-up of the fibres by means of the integrated loom and robotic manipulator system. The cylindrically-shaped fuselage can be unrolled to a two-dimensional plate-like structure. In Figure 8 the unrolled fuselage structure is represented by Blocks Al to AG32. The regions requiring localised reinforcement for the attachment of the main wings are denoted by Blocks E5-10, M5-10, U5-10 and AC5-10 (all red areas). The regions for the tail wings are denoted by Blocks E25-28, M25-28, U25-28 and AC25-28 (all yellow areas). The green region (Blocks Q22-28) is the reinforcement area for the tail. The loom would weave the general fibre layout of the entire structure while the robotic manipulator would be responsible for the localised reinforcement (red, yellow and green areas). Once the process has been completed, the woven fibre layout can then be rolled to form the three- dimensional cylindrically-shaped fuselage.

Claims

PATENT CLAIMS

1. A composite component, which includes a composite material having at least one region with superior and/or complex reinforcement than at least one other region of the composite material.

2. A component as claimed in claim 1, which includes a plate-like and/or cylindrical fibre-reinforced structure and/or other shape.

3. A component as claimed in claim 1 or claim 2, which includes varied structural strengths across the geometry, surface and/or thickness of the composite component.

4. A component as claimed in any one of the preceding claims, which includes complex-shaped components.

5. A component as claimed in any one of the preceding claims, which includes localised reinforcement.

6. A component as claimed in claim 5, in which the localised reinforcement is achieved by manually laying the fibres in the required reinforcement areas in the appropriate directions.

7. A component as claimed in any one of the preceding claims, in which the reinforcement is provided in an infusion proceed by fibres being placed with one end (diamond end) fixed and the other end (arrow end) free or floating .

8. A component as claimed in claim 7, in which correct fibre direction is attained during the infusion process by carefully selecting the infusion point and vacuum point.

9. A component as claimed in claim 8, in which resin flows from the infusion point to the vacuum point, the fibres follow the flow and remain in that direction until curing is complete.

10. A component as claimed in any one of claims 5 to 9, in which the fibres are placed in the appropriate directions with both ends fixed .

11. A component as claimed in any one of claims 5 to 10, in which the fibre orientation is:

(a) radial (as in the case of the edges of a hole);

(b) linear (at preferred angles); (c) concentric (around holes or protrusions); and/or

(d) any combination thereof.

12. A component as claimed in any one of claims 5 to 11, in which fibre concentration varies from a single layer to multiple layers as required or allowed by design.

13. A component as claimed in claim 12, in which the number of layers vary through the cross-section, as may be required, in a gradual shift from a region of high stress concentration to another of lower concentration.

14. A component as claimed in any one of the preceding claims, in which the composite material is two-dimensional such as plate-like structures or three-dimensional such as cylindrical structures.

15. A component as claimed in claim 14, in which the cylindrical structure is a fuselage of an aircraft (aircraft body).

16. A method of fabricating a composite component, which includes the step of laying fibres in at least one region of a composite material that requires further reinforcement than at least one other region of the composite material.

17. A method as claimed in claim 16, which includes the technique known as stitching.

18. A method as claimed in claim 16 or claim 17, which is performed autonomously by means of a robotic manipulator.

19. A method as claimed in any one of claims 16 to 18, in which the manipulator performs the fibre lay-up in a stand-alone environment, i.e. the entire fibre lay-up of a component can be executed by the robotic manipulator, or the manipulator can be integrated into an existing process, such as weaving.

20. A method as claimed in claim 19, in which the step of weaving is performed on a loom which consists mainly of two constituents; the warp and the weft.

21. A method as claimed in claim 20, in which the warp is a set of longitudinal fibres through which the weft is woven and the weft is the fibre that is being woven.

22. A method as claimed in claim 20 or claim 21, in which the loom weaves the fibres according to the general fibre layout of the component, i.e. the fibres will be woven into the directions that are required throughout the part.

23. A method as claimed in any one of claims 20 to 22, in which the robotic manipulator adds fibres to the areas that require localised reinforcement while the loom is weaving the general pattern.

24. A method as claimed in any one of claims 16 to 23, in which orientation and concentration of the localised reinforcement fibre layout is accomplished via known embroidery techniques that range from handcrafted embroidery to computerised machine embroidery which is capable of reading digitised files.

25. A method as claimed in any one of claims 16 to 24, in which the process of performing the fibre lay-up include the steps:

26. A method as claimed in any one of claims 18 to 25, in which filament winding is used to achieve the general fibre lay-up and, during this process, the robotic manipulator executes the fibre lay-up of the localised reinforced areas of the wing and tail sections.

27. An aircraft fuselage, which is made of a composite material having at least one region with superior and/or complex reinforcement than at least one other region of the composite material.

28. A method of fabricating an aircraft fuselage which consists of a composite component, which includes the step of laying fibres in at least one region of a composite material that requires further reinforcement than at least one other region of the composite material.

29. A method as claimed in claim 28, in which a cylindrically-shaped fuselage is unrolled to a two-dimensional plate-like structure.

30. A method as claimed in claim 28 or claim 29, in which a woven fibre layout is adapted to be rolled to form a three-dimensional cylindrically- shaped fuselage.

31. A composite component substantially as hereinbefore described with reference to any of the accompanying drawings.

32. A method of fabricating a composite component substantially as hereinbefore described with reference to any of the accompanying drawings.

33. An aircraft fuselage substantially as hereinbefore described with reference to any of the accompanying drawings.

34. A method of fabricating an aircraft fuselage which consists of a composite component substantially as hereinbefore described with reference to any of the accompanying drawings.