JOINING METHOD AND ASSEMBLY FOR AN AIRCRAFT

Abstract

A joining method and assembly for an aircraft. To improve the characteristics or permit hitherto impossible connections between thermoplastic and thermoset components, a multi-material joining method is disclosed in which a thermoplastic connecting region is formed on the thermoplastic component. The connecting region is connected to the thermoset component by interdiffusion. For this purpose, the uncured second component is brought into contact with the connecting region and heat is supplied. An interdiffusion layer is formed which fixedly connects the second component and the connecting region to one another and thus joins the first component to the second component.

Claims

1. A joining method for joining together a fiber-reinforced first component, which contains a first polymer material as a matrix, to a fiber-reinforced second component, which contains a curable thermosetting second polymer material as a matrix, the method comprising: providing the first component; forming a connecting region on the first component to generate a joining surface on the first component, the connecting region comprising thermoplastic polymer materials and being formed with a plurality of adjacent spatial regions, wherein two adjacent spatial regions each comprise different thermoplastic polymer materials from each other; forming, for the connecting region: a first spatial region and a second spatial region, wherein the first spatial region and the second spatial region are formed in a manner of a planar layer and are adjacent to and parallel to the joining surface in a layer of the connecting region; and/or a plurality of first and second spatial regions, wherein the first spatial regions and the second spatial regions extend in a thickness direction of the connecting region, which is normal to the joining surface of the connecting region, and are arranged alternately in the thickness direction; and arranging a portion of the second component in contact with the joining surface and applying heat to fix the connecting region to the second component while curing the second polymer material to join the second component and the first component together.

2. The joining method of claim 1, wherein: the connecting region is formed with a surface structure region, which has periodic elevations and depressions in at least one direction; or the first spatial region and/or the second spatial region contain short fibers and/or continuous fibers.

3. The joining method of claim 2, wherein, in forming the connecting region: in the thickness direction an extent of the first spatial regions gradually decreases with increasing distance from the first component, while an extent of the second spatial regions gradually increases; and/or the first and second spatial regions form a cellular structure and/or a wavelike structure.

4. The joining method of claim 1, wherein, in forming the connecting region, one of the spatial regions is configured in a form of a core region of the connecting region, the core region being arranged to adjoin the first and second components and adjacent spatial regions.

5. The joining method of claim 4, wherein the core region comprises a fiber-reinforced, thermoplastic polymer material.

6. The joining method of claim 4, wherein, in forming the connecting region, another one of the spatial regions is formed in an outer edge region of the connecting region, the outer edge region being arranged such that the outer edge region extends along a periphery of the connecting region and only adjoins the first and second components and the core region.

7. The joining method of claim 6, wherein: the outer edge region comprises a non-reinforced, thermoplastic polymer material; and/or the outer edge region has a lower melting temperature than the material of the core region.

8. The joining method of claim 4, wherein: in forming the connecting region, another one of the spatial regions is formed in an outer edge region of the connecting region, the outer edge region being arranged such that the outer edge region extends along a periphery of the connecting region and adjoins the first and second components and the core region; and a spatial region is formed as an intermediate region of the connecting region, the intermediate region being arranged between the outer edge region and the core region.

9. The joining method of claim 8, wherein the intermediate region comprises a non-reinforced, thermoplastic polymer material which: is, with exception of fiber direction, identical to the polymer material of the core region, and/or is different from the polymer material of the outer edge region, and/or has a higher melting temperature than the material of the outer edge region.

10. The joining method of claim 1, wherein, in forming the connecting region: a surface structure region is formed on a side of the connecting region facing away from the joining surface; and in a plane parallel to the joining surface, the surface structure region comprises elevations and depressions that are of wavelike design and/or a corrugated or serrated pattern.

11. The joining method of claim 10, wherein the surface structure region is formed such that, in the plane parallel to the joining surface, a form fit is formed between the connecting region and the first component.

12. The joining method of claim 1, wherein: the first polymer material is a thermoplastic polymer material or a thermosetting polymer material; and/or the connecting region contains a polymer material, which has a lower melting temperature than the first polymer material.

13. The joining method of claim 1, wherein the first component and the connecting region are formed by additive manufacturing such that the connecting region is manufactured first and then the first component is manufactured.

14. The joining method of claim 1, wherein: the first spatial region comprises fibers; all of the fibers in the first spatial region extend predominantly in a first direction; the second spatial region comprises fibers; and all of the fibers in the second spatial region extend predominantly in a second direction, which is orthogonal to the first direction.

15. An aircraft assembly formed according to the joining method of claim 1.

16. A joining method for joining together fiber-reinforced first and second components, the method comprising: forming a connecting region, which comprises a plurality of adjacent spatial regions, including at least a first spatial region and a second spatial region that are laterally adjacent to, and coplanar with, each other, in a manner of a planar layer, and, in each case, the first and second spatial regions comprise fibers and have different thermoplastic polymer materials from each other; forming, via additive manufacturing, a first fiber-reinforced component, which comprises a first polymer material as matrix, on the connecting region, such that the connecting region and the first component are attached together to provide a joining surface on the first component; forming a fiber-reinforced second component, which comprises a curable thermosetting second polymer material as matrix; and arranging, after the connecting region and the first component are attached together, a region of the second component in contact with the joining surface and supplying heat to fix the connecting region to the second component while curing the second polymer material to join the first component to the second component; wherein all of the fibers in the first spatial region extend predominantly in a first direction and all of the fibers in the second spatial region extend predominantly in a second direction, the second direction being orthogonal to the first direction.

17. The joining method of claim 16, wherein, in forming the connecting region: the first spatial region comprises the first polymer material and the second spatial region comprises a thermoplastic polymer material, which is different from the first polymer material; and/or the first spatial region and/or the second spatial region contain short fibers and/or continuous fibers; and/or the first spatial region and the second spatial region form, together, a sheet-like layer for the connecting region, the layer extending parallel to the joining surface.

18. The joining method of claim 17, wherein, in forming the connecting region: as viewed in a thickness direction, which extends normal to the joining surface, an extent of the first spatial region gradually decreases and an extent of the second spatial region gradually increases as a distance in the thickness direction from the first component increases; and/or the first and second spatial regions form a cellular structure.

19. The joining method of claim 16, wherein: in forming the connecting region, one of the spatial regions is configured in a form of a core region of the connecting region, the core region being arranged to adjoin the first and second components and adjacent spatial regions; and either: the core region comprises a fiber-reinforced, thermoplastic polymer material; or in forming the connecting region, another one of the spatial regions is configured in a form of an outer edge region of the connecting region, the outer edge region being arranged such that the outer edge region extends along a periphery of the connecting region and adjoins the first and second components and the core region.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Example embodiments will be explained in more detail with reference to the appended schematic drawings, in which:

[0044] FIG. 1 through FIG. 8 show example embodiments of an assembly;

[0045] FIG. 9 shows detail views (a) through (f) of different examples of connecting regions; and

[0046] FIG. 10 through FIG. 13 show an example embodiment of a joining method.

DETAILED DESCRIPTION

[0047] Reference is first of all made to FIG. 1, which shows an assembly 10. The assembly 10 comprises a first component 12 and a second component 14, which are connected to one another via a connecting region 16.

[0048] The assembly 10 is for example intended for an aircraft. The first component 12 can be a reinforcing component, for instance a stringer. The second component 14 can be a fuselage component, for example an outer skin which is intended to be reinforced by the first component 12.

[0049] The first component 12 is a fiber-reinforced component which contains a matrix composed of a first polymer material 18. The first polymer material 18 is selected from the group of polyaryletherketones, for example PEEK.

[0050] The second component 14 is a fiber-reinforced component which contains a matrix composed of a thermosetting second polymer material 20. The second polymer material 20 is for example epoxy resin.

[0051] The connecting region 16 is composed of a thermoplastic polymer material, for example PEI. The connecting region 16 can be configured in the form of a film or in the form of a foil.

[0052] The first component 12 and the connecting region 16 are fused together at a melt layer 22. This can be achieved for example in that the first component 12 is additively manufactured on the connecting region 16.

[0053] The connecting region 16 also has a joining surface 24 which preferably lies opposite the melt layer 22.

[0054] The second component 14 is arranged with a region in contact with the joining surface 24. In this state, the second polymer material 20 is still in the curable state. Heat is then supplied in order to heat the first polymer material 18 above its glass transition temperature and to activate the curing of the second polymer material 20. In this case, an interdiffusion layer 26 is produced between the second component 14 and the connecting region 16. The connecting region 16 is then fixed to the second component 14, and therefore overall the first component 12 and the second component 14 have been joined to form the assembly 10.

[0055] The further example embodiments are explained merely insofar as they differ from the example described above.

[0056] As indicated in FIG. 2, the connecting region 16, similarly to the first component 12, is generated by additive manufacturing. In the sequence, the connecting region 16 is initially generated and then the first component 12 is constructed on the connecting region 16. The method then proceeds as described above.

[0057] FIG. 3 shows a connecting region 16 which is additively manufactured from a fiber-reinforced thermoplastic first polymer material 18, for example fiber-reinforced PEI. The fibers are for example continuous fibers and can be arranged at angles of +45° and -45°.

[0058] It is also possible for the connecting region 16 to contain more than one layer, with a fiber direction that alternates in each case from layer to layer. Accordingly, the connecting region 16 has a first spatial region 28 with a first fiber direction and a second spatial region 30 with a second fiber direction, which may be orthogonal to the first fiber direction. The method then proceeds as described above.

[0059] It should be noted that the second spatial region 30 is considered to be composed of a different polymer material compared with the first spatial region 28 because the fibers extend in another direction.

[0060] FIG. 4 shows a connecting region 16 which is additively manufactured. The connecting region 16 contains a first spatial region 28 and a second spatial region 30.

[0061] The first spatial region 28 is configured in the form of an outer edge region 32. The outer edge region 32 has an exposed side 33. The outer edge region 32 is for example composed of non-reinforced thermoplastic, such as PEI.

[0062] The second spatial region 30 is configured in the form of a core region 34. The core region 34 adjoins the outer edge region 32, the first component 12 and the second component 14. The core region 34 is for example composed of fiber-reinforced thermoplastic, such as PEI. The core region 34 can have different fiber directions, as described above.

[0063] FIG. 5 shows a connecting region 16 which is additively manufactured. The connecting region 16 contains a first spatial region 28 and a second spatial region 30.

[0064] The first spatial region 28 is configured in the form of an outer edge region 32 and in the form of a core region 34. The first spatial region 28 is for example composed of a fiber-reinforced thermoplastic such as PEI, wherein the fibers extend at an angle of 90° relative to the first component 12 or the second component 14.

[0065] The second spatial region 30 is configured in the form of an intermediate region 36 which is arranged between the outer edge region 32 and the core region 34. The second spatial region 30 is for example composed of a fiber-reinforced thermoplastic such as PEI.

[0066] In contrast to the first spatial region 28, the fibers extend at an angle of 0°. It should be noted that the second spatial region 30 is considered to be composed of a different polymer material compared with the first spatial region 28 because the fibers extend in another direction.

[0067] FIG. 6 shows a connecting region 16 which is additively manufactured. The connecting region 16 contains a first spatial region 28, a second spatial region 30, a third spatial region 38 and a fourth spatial region 40.

[0068] The first spatial region 28 is configured in the form of an outer edge region 32. The outer edge region 32 is composed of a non-reinforced thermoplastic polymer material, for example polyamide or thermoplastic polyurethane, wherein the polymer material has a low melting temperature.

[0069] The second spatial region 30 is configured in the form of an intermediate region 36. The intermediate region 36 is composed of a non-reinforced thermoplastic polymer material such as PEI. The intermediate region 36 has a higher melting temperature than the outer edge region 32.

[0070] The third spatial region 38 is configured in the form of a further intermediate region 42 which is arranged between the intermediate region 36 and the core region 34. The further intermediate region 42 is composed of a fiber-reinforced thermoplastic polymer material such as PEI, in which the fibers extend at an angle of 90°.

[0071] The fourth spatial region 40 is configured in the form of a core region 34. The core region 34 is composed of a fiber-reinforced thermoplastic polymer material such as PEI, in which the fibers extend at an angle of 0°.

[0072] FIG. 7 shows a connecting region 16 which is additively manufactured. The connecting region 16 is formed with a surface structure region 44 on which the melt layer 22 is formed. The surface structure region 44 is structured such that a form fit is generated in a plane parallel to the joining surface 24. The surface structure region 44 can have periodically alternating elevations 46 and indentations 48. The surface structure region 44 can be configured in a wavelike manner, with a grooved or serrated pattern and/or the like.

[0073] FIG. 8 shows a connecting region 16 which is additively manufactured. The connecting region 16 is formed such that, in the thickness direction D, there is a gradual transition between the polymer material of the connecting region 16 and the first polymer material 18. By way of example, a plurality of polymer layers 50 are generated, wherein the proportion of polymer lines composed of the first polymer material 18 increases layer by layer. The first spatial region 28 and the second spatial region 30 are produced by the various polymer lines.

[0074] FIG. 9 shows further examples of such a system composed of polymer layers 50 with the first spatial region 28 and the second spatial region 30. The transition can be designed in the form of a cellular structure or regions which are arranged periodically in alternation, as are illustrated in FIG. 9.

[0075] The joining method is elucidated with reference to FIG. 10 to FIG. 12. The first component 12 is initially provided with the connecting region 16. The provision can be effected in that the first component 12 and the connecting region 16 are additively manufactured. Preferably, the connecting region 16 is manufactured first or at the same time as the first component 12. The connecting region 16 is configured in any, or an expedient, combination of the examples described above.

[0076] Looking at FIG. 11, a region of the second component 14 is brought into contact in the uncured state with the joining surface 24. The second component 14 can be a textile preform, a carbon fiber-reinforced plastics part or the like. If required, the second component 14 is infused in the position.

[0077] As illustrated in FIG. 12, the assembly 10 is subsequently finished by supply of heat. The first component 12 is then joined to the second component 14 to form the assembly 10, which is schematically illustrated in FIG. 13.

[0078] In order to improve the characteristics or permit hitherto impossible connections between thermoplastic and thermoset components 12, 14, a multi-material joining method is proposed in which a thermoplastic connecting region 16 is formed on the thermoplastic component 12. The connecting region 16 is connected to the thermoset component 14 by interdiffusion. For this purpose, the uncured second component 14 is brought into contact with the connecting region 16 and heat is supplied. An interdiffusion layer 26 is formed which fixedly connects the second component 14 and the connecting region 16 to one another and thus joins the first component 12 to the second component 14.

[0079] While at least one example embodiment of the present invention(s) is disclosed herein, it should be understood that modifications, substitutions and alternatives may be apparent to one of ordinary skill in the art and can be made without departing from the scope of this disclosure. This disclosure is intended to cover any adaptations or variations of the example embodiment(s). In addition, in this disclosure, the terms ″comprise″ or ″comprising″ do not exclude other elements or steps, the terms ″a″, ″an″ or ″one″ do not exclude a plural number, and the term ″or″ means either or both. Furthermore, characteristics or steps which have been described may also be used in combination with other characteristics or steps and in any order unless the disclosure or context suggests otherwise. This disclosure hereby incorporates by reference the complete disclosure of any patent or application from which it claims benefit or priority.

TABLE-US-00001 List of reference designations: 10 Assembly 12 First component 14 Second component 16 Connecting region 18 First polymer material 20 Second polymer material 22 Melt layer 24 Joining surface 26 Interdiffusion layer 28 First spatial region 30 Second spatial region 32 Outer edge region 33 Exposed side 34 Core region 36 Intermediate region 38 Third spatial region 40 Fourth spatial region 42 Further intermediate region 44 Surface structure region 46 Elevation 48 Indentation 50 Polymer layer D Thickness direction