METHOD FOR REPAIRING A FIBER COMPOSITE COMPONENT

Abstract

The invention relates to a method for repairing a damaged point of a fiber composite component which is formed from at least one fiber ply of a fiber material of a fiber composite substance and a matrix material of the fiber composite substance, in which matrix material the fiber material is embedded, wherein the method comprises the following steps: removing the damaged point from the fiber composite component and producing a repair cavity in the fiber composite component, introducing at least one reparative fiber ply of a fiber material into the repair cavity produced in the fiber composite component, and curing the matrix material, in which the fiber material of the reparative fiber ply is embedded, after introducing the reparative fiber ply into the repair cavity of the fiber composite component,

wherein at least one reparative fiber ply having a ply thickness that is smaller than the ply thickness of the fiber plies of the rest of the fiber composite component is introduced into the repair cavity.

Claims

1. A method for repairing a damaged point of a fiber composite component which is formed from a plurality of fiber plies of a fiber material of a fiber composite substance and a matrix material of the fiber composite substance, in which the matrix material of the fiber material is embedded, comprising: removing the damaged point from the fiber composite component and producing a repair cavity in the fiber composite component, introducing at least one reparative fiber ply of a repair fiber material into the repair cavity produced in the fiber composite component, wherein the at least one fiber ply is embedded in a repair matrix material, and consolidating the matrix material with the repair matrix materialin which the repair fiber material is embedded after introducing the at least one reparative fiber ply into the repair cavity of the fiber composite component, wherein the at least one reparative fiber ply introduced into the repair cavity has a ply thickness that is smaller than a ply thickness of at least one of the plurality of fiber plies of the fiber composite component.

2. The method as claimed in claim 1, wherein the repair cavity in the fiber composite component is produced by forming a scarfing in a region of the damaged point.

3. The method as claimed in claim 1, wherein the at least one reparative fiber ply comprises a plurality of reparative fiber plies, and wherein the plurality of reparative fiber plies are arranged in a stepped manner in the repair cavity such a way that a second reparative fiber ply of the plurality of reparative fiber plies which is placed on a first reparative fiber ply of the plurality of reparative fiber plies, has a larger extent in at least one direction than the first reparative fiber ply.

4. The method as claimed in claim 1 wherein the at least one reparative fiber ply comprises a plurality of reparative fiber plies, and wherein all of the reparative fiber plies introduced in the repair cavity have a ply thickness that is smaller than the ply thickness of each of the plurality of fiber plies of the fiber composite component.

5. The method as claimed in claim 1 wherein at least one reparative fiber ply is preimpregnated with the repair matrix material, or wherein the repair fiber material is infused with the repair matrix material before or after the introduction of the at least one reparative fiber ply into the repair cavity produced.

6. The method as claimed in claim 1 wherein the ply thickness of the at least one reparative fiber ply is less than 80% of the ply thickness of the at least one of the plurality of fiber plies the fiber composite component.

7. The method as claimed in claim 1 wherein the ply thickness of the at least one reparative fiber ply is less than 100 g/m.sup.2.

8. The method as claimed in claim 1 wherein the at least one of the plurality of fiber plies of the fiber composite component has a ply thickness of more than 100 g/m.sup.2.

9. The method as claimed in claim 1 wherein the at least one reparative fiber ply comprises a plurality of reparative fiber plies, and wherein the plurality of reparative fiber plies are introduced into the repair cavity such that the second reparative fiber ply of the plurality of reparative fiber plies which is placed on a first reparative fiber ply of the plurality of reparative fiber plies has a main fiber direction which differs from the first reparative fiber ply.

10. The method as claimed in claim 9, wherein the main fiber direction differs by an angle of +/−30°.

11. The method as claimed in claim 1 further comprising placing one or more covering fiber plies onto the at least one reparative fiber ply introduced in the repair cavity.

12. The method as claimed in claim 11, wherein at least one of the one or more covering fiber plies has a larger extent than the repair cavity in at least one direction, and/or wherein at least one of the one or more covering fiber plies has a ply thickness that is smaller than or equal to the at least one reparative fiber ply of the repair cavity.

13. The method as claimed in claim 1 wherein the ply thickness of the at least one reparative fiber ply is less than 60% of the ply thickness of the at least one of the plurality of fiber plies of the fiber composite component.

14. The method as claimed in claim 1 wherein the ply thickness of the at least one reparative fiber ply is less than 40% of the ply thickness of the at least one of the plurality of fiber plies of the fiber composite component.

15. The method as claimed in claim 1 wherein the ply thickness of the at least one reparative fiber ply is less than 75 g/m.sup.2.

16. The method as claimed in claim 1 wherein the ply thickness of the at least one reparative fiber ply is less than 50 g/m.sup.2.

17. The method as claimed in claim 1 wherein the at least one of the plurality of fiber plies of the fiber composite component has a ply thickness of more than 135 g/m.sup.2.

18. The method as claimed in claim 9 wherein the main fiber direction differs by an angle of +/−45°.

19. The method as claimed in claim 9 wherein the main fiber direction differs by an angle of +/−60°.

20. The method as claimed in claim 9 wherein the main fiber direction differs by an angle of +/−90°.

Description

[0034] The invention will be explained in more detail and by way of example on the basis of the appended FIGURE, in which:

[0035] FIG. 1—shows a schematic illustration of a repaired fiber composite component.

[0036] FIG. 1 shows a fiber composite component 10, which, for illustrative purposes, comprises only four fiber plies 11 of a fiber material of a fiber composite component. In this case, the four fiber plies are arranged one on top of the other and consolidated by curing a matrix material, in which the fiber material of the fiber plies 11 is embedded, to form an integral unit. In this respect, each of the fiber plies 11 has a main fiber direction which may differ from one fiber ply to another, in order to thus obtain as good as possible a load-bearing property in the entire areal plane of the fiber composite component 10 and to at least approximate the properties of isotropic and anisotropic substances.

[0037] Now, the fiber composite component 10 exhibited damage in the first two top fiber plies 11a and 11b of the fiber composite component 10, and therefore it was necessary to repair the fiber composite component 10. For this, a repair cavity 12, which may be produced for example by boring, grinding or milling, was created by removing the damaged point. In the process, the first three top fiber plies 11a, 11b and 11c were removed in the region of the repair cavity 12, in order to thus make space for a corresponding repair patch.

[0038] Here, the repair cavity 12 is realized in the form of a scarfing, in which the edge regions are slanted toward the base of the repair cavity.

[0039] Reparative fiber plies 13 are now introduced one after the other into the repair cavity 12 thus formed, in order to refill the formed repair cavity 12 with fiber material. The reparative fiber plies 13 that were introduced into the repair cavity 12 in this respect have a ply thickness d.sub.2 that is smaller than the ply thickness d.sub.1 of the fiber plies 11 of the fiber composite component 10.

[0040] The ply thickness of a fiber ply or of a reparative fiber ply is understood here to mean the maximum extent of the fiber material orthogonally to the fiber ply plane of the fiber plies.

[0041] On account of the fact that the reparative fiber plies have a smaller ply thickness d.sub.2 than the ply thickness d.sub.1 of the fiber plies 11 of the fiber composite component 10, it is possible to introduce a greater number of reparative fiber plies 13 into the repair cavity 12 than the number of fiber plies 11 of the fiber composite component 10 that were removed from the fiber composite component 10 in the region of the repair cavity 12.

[0042] In a schematically idealized form, in FIG. 1 the reparative fiber plies 13 are formed in such a way that two reparative fiber plies 13 placed in the repair cavity 12 correspond to one respective fiber ply 11 of the fiber composite component 10. If it is now the case that these two reparative fiber plies 13, which are assigned to one fiber ply 11 of the fiber composite component 10, have a main fiber direction that varies between these two reparative fiber plies 13, it is possible to have the effect that, in relation to a fiber ply 11 of the fiber composite component 10 at the repaired location, the patch within the repair cavity 12 obtains a better load-bearing property and therefore possible disadvantages of the repair can be compensated.

[0043] Furthermore, the effect of the smaller ply thickness d.sub.2 compared to the fiber plies 11 of the fiber composite component 10 is that in the edge region 14 the step effect caused by the adjacent reparative fiber plies 13 is reduced, and as a result of the smaller ply thickness there is a greater ply resolution in the edge region 14. This makes it possible to reduce the volume of resin pockets or adhesive pockets in the edge region 14 of the repair cavity 12, as a result of which it is likewise possible to increase the strength and rigidity of the repair patch.

[0044] In the exemplary embodiment of FIG. 1 it is furthermore shown that lastly, as the top covering ply 15, a reparative fiber ply is likewise placed on, the ends of which protrude beyond the repair cavity 12. The covering ply 15 may also have a ply thickness that is smaller than the ply thickness d.sub.1 of the fiber plies 11 of the fiber composite component, as a result of which it is possible to reduce jumps in the outer surface 16 of the fiber composite component. This is especially advantageous in particular in the case of surfaces around which an aerodynamic flow passes, since this makes it possible to reduce the air resistance.

LIST OF REFERENCE SIGNS

[0045] 10—Fiber composite component

[0046] 11—Fiber plies

[0047] 12—Repair cavity

[0048] 13—Reparative fiber plies

[0049] 14—Edge region

[0050] 15—Covering ply

[0051] 16—Outer surface

[0052] d.sub.1—Ply thickness of the fiber plies 11

[0053] d.sub.2 Ply thickness of the reparative fiber plies 13