DE102020113677A1 - A connection comprising a first component, a second component and a connection arrangement - Google Patents

Abstract

The invention relates to a connection comprising a first component formed from a fiber composite material comprising a fiber material and a matrix material embedding the fiber material, at least one second component and an overlapping connection arrangement formed within a joining section with which the components are connected to one another, the first component being within the Joining portion is severed to form a plurality of connecting tabs.

Description

The invention relates to a connection comprising a first component, at least one second component and an overlapping connection arrangement formed within a joining section, with which the components are connected to one another, the first component being formed from a fiber composite material comprising a fiber material and a matrix material embedding the fiber material.

Due to the weight-specific strength and rigidity of fiber composite components made from a fiber composite material, such components are nowadays unimaginable in the aerospace industry and in many other areas of application, such as the automotive sector. In the production of a fiber composite component, a matrix material embedding the fiber material is cured mostly under the application of temperature and pressure and thus forms an integral unit with the fiber material after curing. The reinforcing fibers of the fiber material are thereby forced in their specified direction and can transfer the occurring loads in the specified direction.

Fiber composite materials from which such fiber composite components are produced generally have two main components, namely on the one hand a fiber material and on the other hand a matrix material. In addition, other secondary components can be used, such as binder materials or additional functional elements that are to be integrated into the component. If dry fiber materials are provided for the production, then during the production process the matrix material of the fiber composite material is infused into the fiber material by an infusion process through which the dry fiber material is impregnated with the matrix material. This usually happens due to a pressure difference between the matrix material and the fiber material, for example by evacuating the fiber material by means of a vacuum pump. In contrast to this, fiber composite materials are also known in which the fiber material is already pre-impregnated with the matrix material (so-called prepregs).

Due to the special advantages, fiber composite components have also established themselves in aircraft construction in order to be able to exploit the advantages of lightweight construction in particular. There is an effort to manufacture not only the fuselage of an aircraft (commercial aircraft), but also the flow profiles (wings and tail units) entirely from a fiber composite material. Due to the exposed position of a wing leading edge, however, it must be arranged on the wing or tail box, in particular in a detachable manner, in order to be able to replace it if it is damaged. In addition, a leading edge of a wing made of a fiber composite material should be protected against impact damage and erosion caused by e.g. sand and rain, which can be achieved, for example, with an erosion protection layer.

The flow surface of such a flow profile should also be designed in such a way that, starting from the leading edge of the wing, the longest possible laminar boundary layer flow is formed in order to save energy costs when moving the aircraft in the air. Bolted connections between the leading edge of the wing and the wing box, as they are typically used in aviation, are usually not suitable for this, as this creates steps and edges in the flow surface that favor a transition from a laminar flow to a turbulent flow.

In practice, one of the joining partners (usually the side of the wing box) is usually separated so that the leading edge of the wing can be placed over this separated joining section of the wing box. This creates an overlapping connection. Since fiber composite components have relatively large fluctuations in thickness and often also have global geometrical deviations, the precision that can be achieved with a conventional connection is not sufficient to ensure the narrow requirements (<0.2 mm with high Reynolds numbers) of a laminar transition. As a solution for laminar-compatible connections, a temporary filling of the joint has currently established itself in flight tests, but this is very complex and difficult to imagine in a series application. In addition, the effort involved in changing the leading edge of the sash is very high, since all of the filler has to be removed.

It is therefore the object of the present invention to provide an improved connection, in particular between a wing leading edge and a wing box, in which thickness fluctuations and global geometrical deviations do not have a negative effect on a laminar boundary layer flow.

The object is achieved according to the invention with the features according to claim 1. Advantageous refinements of the invention can be found in the corresponding subclaims.

According to claim 1, a compound comprising a first component, at least one second component and an overlapping connection arrangement formed within a joining section, in which the first component and the second component are pushed over one another within the joining section for joining the two components. In cross-section, the first component runs within the joining section under the second component or the other way around, so that an outer side of one of the components in the joining section rests against an inner side of the other component or is opposite to it.

At least the first component is formed from a fiber composite material that has a fiber material and a matrix material that embeds the fiber material. Such a fiber composite material can be a CFRP or GFRP, for example. The at least second component can also be formed from a fiber composite material that can be identical to or different from the fiber composite material of the first component.

According to the invention, it is now provided that the first component is severed within the joining section in order to form a plurality of connecting straps.

The first component is cut or slotted in the joining section, as a result of which a plurality of individual, separate connecting straps are created, which are materially connected to the first component only on one side. Adjacent connecting straps are no longer connected to one another due to the severing.

The (deliberately) created flexibility in the spanwise direction through the formation of the tabs makes it possible to arrange the first component within the joining section without gaps on the second component, for example in a form-fitting and / or force-fitting manner, even if the first component and / or the second component have large fluctuations in thickness or high global geometry deviations. It has been shown that, despite the severing for the production of the connecting straps, the first component still has such a strength and rigidity that it particularly satisfies the stresses of a wing leading edge, while on the other hand flexibility is achieved in the joining section with which geometrical deviations can be compensated reliably.

The structure of the fiber material is severed during the severings in the first component, so that a desired flexibility is achieved in the direction of the span. The first component is thus structurally weakened with the cuts in order to obtain the desired flexibility to compensate for the geometrical deviations.

The connection arrangement can include various measures for connecting the first component and the second component within the joining section, such as a mechanical connection by means of screws and / or bolts and / or a material or chemical connection by means of adhesive.

According to one embodiment it can be provided that an in particular detachable sheet metal strip for covering the openings is arranged on the first component at least in the joining section.

If a mechanical connection by means of screws and / or bolts is used, it is advantageous if, within the joining section in the first and / or second component, corresponding receptacles (e.g. boreholes or feedthroughs) are provided in order to connect the mechanical connecting means such as e.g. screws or Passing bolts in the joining section through the first and / or second component or in order to connect the first component to the second component by means of the mechanical connecting means. The receptacles in the first component (e.g. drilled holes or feedthroughs) are located in the respective connecting straps.

According to one embodiment, it can be provided that the receptacles for the mechanical connecting means are still accessible in order to create a particularly detachable connection. However, it is also conceivable that the receptacles for the mechanical connecting means are closed with covers (for example caps or lids), which in particular end flush with the outer surface of the first component.

According to one embodiment, it is provided that the joining section of the connection arrangement is formed in an edge region of the components and the cuts in the first component extend from an end face of the edge region in the direction of the first component and / or away from the second component.

According to one embodiment it is provided that the cuts run essentially perpendicular to the end face.

According to one embodiment it is provided that the second component is guided under the first component or the first component is guided under the second component within the joining section. It can be provided that the second component also has corresponding cuts to form connecting tabs.

According to one embodiment it is provided that at least a certain number of the connecting tabs formed are each connected to the second component independently of one another by means of a connecting element. What is meant here is a connecting element which connects the respective connecting tab to the second component independently of the other connecting tabs. This can be, for example, gluing the respective connecting strap to the second component. However, this can also be a mechanical connecting means (such as, for example, screw or bolt) which is passed through the respective connecting strap and the second component in openings provided for this purpose.

According to one embodiment, it is provided that at least a certain number of the connecting straps formed are each connected in a form-fitting and / or force-locking manner by means of at least one connecting element (connecting means) guided through the respective connecting strap and the second component.

According to one embodiment, it is provided that a protective layer is arranged on the first component, which layer extends from the first component to at least the joining section or beyond in the direction of the second component. Such a protective layer can be, for example, an erosion protection layer which is intended to protect at least the first component and the joining section. In addition, the protective layer can be used to compensate for geometrical deviations in the entire surface or within the joint section after the two components have been joined. For this purpose, the protective layer is designed in particular to be semi-flexible or flexible, so that it can adapt to the unevenness.

According to one embodiment it is provided that the protective layer is glued to the first component and optionally to the second component. Thus, after the two components have been joined, the protective layer can be glued onto the first component and over the joining section, preferably into the second component. The combination of protective layer, adhesive and component can now be pressed precisely to the required thickness via an adapted amount of adhesive and, if necessary, mechanical limitation of the setting path. Excess adhesive can escape on the sides of the individual connecting tabs. The mechanical limitation during the gluing process can, if necessary, be adapted to the measured actual values of the remote side of the component.

In addition, the cutouts for forming the connecting tabs in the first component are completely covered by the protective layer. The transition between the first component and the second component in the joining section is now largely or completely step-free, so that a laminar boundary layer is favored. The subsequent application of the protective layer to the joined components also means that remaining faults such as screw heads within the joining section can also be covered by the protective layer.

According to one embodiment it is provided that the protective layer is formed from a metal material.

According to one embodiment it is provided that the connection is an aircraft connection, in which the first component forms a wing leading edge and the second component forms a wing box of an aircraft.

The object is also achieved according to the invention with the method according to claim 11. Advantageous refinements of the method can be found in the corresponding subclaims.

The object is also achieved according to the invention with a flow profile leading edge according to claim 14 and a wing according to claim 16.

• 1 schematische Darstellung der Anbindung einer Flügelvorderkante im Querschnitt nach dem Stand der Technik;
• 2 schematische Draufsicht einer erfindungsgemäßen Flügelvorderkante;
• 3 perspektivische Darstellung der erfindungsgemäßen Flügelvorderkante
• 4 perspektivische Darstellung der erfindungsgemäßen Flugzeugverbindung.

The invention is explained in more detail by way of example with the aid of the accompanying figures. Show it:

• 1 schematic representation of the connection of a wing leading edge in cross section according to the prior art;
• 2 schematic top view of a wing leading edge according to the invention;
• 3 perspective view of the wing leading edge according to the invention
• 4th perspective view of the aircraft connection according to the invention.

1 shows a schematic representation of a wing leading edge 10 that have a connection arrangement 11 on a wing box 12th is arranged. To produce the connection arrangement 11 according to the prior art is within a joining section 13th an edge area 14th of the wing box 12th offset or lower, so that an edge area 15th the leading edge of the wing 10 over the edge area 14th of the wing box 12th to form an overlapping connection arrangement 11 can be pushed. Then within the joining section 13th a mechanical connector 16 in the form of a bolt or a screw passed through both components to the leading edge of the wing 10 on the wing box 12th to connect positively and / or non-positively.

In the joining section 13th arises with this procedure from the prior art due to the tolerance-affected lowering of the wing box 12th in the area of the joining section 13th a step or a gap 17th , which represents a disturbance in the flow surface and has an unfavorable effect on a laminar boundary layer flow. Therefore, this area is in the state of the art and for testing purposes for researching laminarization with a filler 18th filled out and elaborately edited.

However, this approach has the disadvantage that due to geometrical deviations of the wing leading edge 10 or the wing box 12th despite the filler 18th the transition from the wing leading edge 10 to the wing box 12th is not so uniform that the laminar boundary layer flow is maintained. In production aircraft, the increase in drag caused by a turbulent flow behind the connection point of the leading edge of the wing is accepted. Smoothing the transition area by filling, as in the research area, is not economically feasible here.

According to the invention, a wing leading edge is used for this purpose 10 suggested that in the area of the joining section 13th a plurality of cuts 19th has, so that a plurality of connecting tabs 20th are formed within the joining section 13th are independent of each other. This is schematically shown in a plan view in FIG 2 shown.

Each through the cuts 19th formed connecting tab 20th has at least one hole or opening 21 on, through the joining of the wing leading edge 10 to the wing box 12th the mechanical connecting element 16 ( 1 ) should be passed through. The opening 21 can be designed so that the mechanical connecting element 16 essentially planar or level with the surface of the leading edge of the wing 10 closes, is covered by an outer layer or is covered by a cover over the screw connection.

The severings 19th extend from one end face 22nd of the edge area 15th the leading edge of the wing 10 away from this in the direction of the wing leading edge 10 and thus away from the wing box 12th .

3 shows a perspective view of the wing leading edge according to the invention 10 , in the 4th is installed in the connection shown in perspective there. On the leading edge of the wing 10 is a protective layer 23 by means of an adhesive layer 24 arranged. The leading edge of the wing 10 has severations 19th to select the corresponding connecting straps 20th to build.

The embodiment of the 4th shows an embodiment in which in the protective layer 23 continue the openings 21 for the mechanical fasteners 16 are accessible, so that the leading edge of the sash even after joining 10 from the wing box 12th Can be removed without first protective layer 23 to have to remove. This in the protective layer 23 Any remaining openings can then be closed with suitable mechanical elements or with a filler.

The protective layer 23 is done after joining the leading edge of the wing 10 to the wing box 12th especially in the joining section 13th glued on with the help of a layer of adhesive 24 . By adjusting the thickness of the adhesive layer accordingly 24 can be the component thickness in the area of the joining section 13th adjusted accordingly in order to obtain a flat and even flow surface.

With the present invention it is thus possible, based on the two measures, namely that joining by means of connecting straps on the one hand and the subsequent gluing of a protective layer with adjustment of the adhesive layer thickness on the other, to attach a wing leading edge made of a fiber composite material together with an erosion protection layer on a wing box without the normal operation the laminar boundary layer flow is impaired.

List of reference symbols

10

Wing leading edge / first component

11

Connection arrangement

12th

Wing box / second component

13th

Joining section

14th

Edge area of the wing box / the second component

15th

Edge area of the wing leading edge / the first component

16

mechanical fastener

17th

Step / gap

18th

Filler

19th

Severings

20th

Connecting straps

21

openings

22nd

End faces

23

Protective layer

24

Adhesive layer

Claims (16)

Connection comprising a first component (10) formed from a fiber composite material comprising a fiber material and a matrix material embedding the fiber material, at least one second component (12) and an overlapping connection arrangement (11) formed within a joining section (13) with which the components (10 , 12) are connected to one another, characterized in that at least the first component (10) is severed within the joining section (13) in order to form a plurality of connecting straps (20). Connection after Claim 1 , characterized in that the joining section (13) of the connecting arrangement (11) is formed in an edge region (14, 15) of the components (10, 12) and the cuts (19) in the first component (10) extend from an end face (22) of the edge region (14, 15) extend in the direction of the first component (10) and / or away from the second component (12). Connection after Claim 2 , characterized in that the cuts (19) run essentially perpendicular to the end face (22). Connection according to one of the preceding claims, characterized in that within the joining section (13) the second component (12) is guided under the first component (10) or the first component (10) is guided under the second component (12). Connection according to one of the preceding claims, characterized in that at least a certain number of the connecting straps (20) formed are each connected to the second component (12) independently of one another by means of a connecting element (16). Connection according to one of the preceding claims, characterized in that at least a certain number of the connecting straps (20) formed are connected positively and / or non-positively by means of at least one connecting element (16) guided through the respective connecting strap (20) and the second component (12) are. Connection according to one of the preceding claims, characterized in that a protective layer (23) is arranged on the first component (10), which extends from the first component (10) to at least the joining section (13) or beyond in the direction of the second Component (12) extends. Connection after Claim 7 , characterized in that the protective layer (23) is arranged adhesively by means of an adhesive. Connection after Claim 7 or 8th , characterized in that the protective layer (23) is formed from a metal material. Connection according to one of the preceding claims, characterized in that the connection is an aircraft connection, in which the first component (10) forms a wing leading edge and the second component (12) forms a wing box of an aircraft. A method for producing a connection between a first component (10) and at least one second component (12) by means of an overlapping connection arrangement formed within a joining section (13), the method comprising the following steps: - Provision of a first component (10) and a second component (12), at least the first component (10) being formed from a fiber composite material comprising a fiber material and a matrix material embedding the fiber material, - The first component (10) being provided within the joining section (13) cut in such a way that a plurality of connecting tabs (20) are formed, and - Joining the first component (10) and the second component (12) within the joining section (13) to form the overlapping connection arrangement (11), the respective connection tabs (20) being arranged on the second component (12). Procedure according to Claim 11 , characterized in that after joining the first component (10) and the second component (12), a protective layer (23) is arranged on the first component (10) and the joining section (13), which may extend into the second Component (12) extends. Procedure according to Claim 11 or 12th , characterized in that the cuts (19) are made in the first component (10) before joining. Flow profile leading edge (10) of a flow profile, characterized in that the Airfoil leading edge (10) is severed within a joining section (13) to form a plurality of connecting straps (20) for attachment to an airfoil assembly (12) of the airfoil. Flow profile leading edge (10) after Claim 14 , characterized in that the flow profile leading edge is made from a fiber composite material comprising a fiber material and a matrix material embedding the fiber material. A wing comprising a wing leading edge (10) and a wing box (12), the wing leading edge (10) being connected within a joining section (13) to the wing box (12) in an overlapping connection arrangement (11), characterized in that the wing leading edge (10 ) is severed within the joining section (13) in order to form a plurality of connecting straps (20) for attachment to the wing box (12) of the wing.

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