DE102006048641A1 - Connecting structure for aircraft or spacecraft, has stringer connected with structure component, and high-impact strength material for local increase of power consumption ability of connecting areas attached in one of connecting areas - Google Patents

Abstract

The connecting structure has a stringer (11), which is connected with a structure component (3) over connecting areas (8-10). A high-impact strength material (5) for local increase of the power consumption ability of the connecting areas is attached in one of the connecting areas. The high-impact strength material is thermoplastic material. The structure component and/or the stringer is formed of a fiber composite material. An independent claim is also included for a method for manufacturing a connecting structure for an aircraft or a spacecraft.

Description

The The present invention relates to a connection structure for a Air or spacecraft and a method for producing such Connection structure for an aircraft or spacecraft.

Even though Applicable to any connection structures, the present Invention and its underlying problem with respect to a explained by means of stringers fuselage shell of an aircraft.

fuselage shells and Stringer are increasingly made of fiber composites, in particular carbon fiber reinforced Plastic (CFK), manufactured. Fuselage shells and stringer points thereby a structure of several layers of fiber fabric, which means a cured one Resin matrix, in particular epoxy resin, are interconnected. typically, are called Stringer T-Stringer, which has a foot on which it attaches to the fuselage shell are connected, and have a web portion, which is substantially extends perpendicular to the fuselage shell, for stiffening the fuselage shell used. This is the foot of the T-stringer connected by means of the resin matrix with the fuselage shell.

Under normal operating conditions of an aircraft act in the fuselage shell tensile, compressive and shear stresses parallel to the hull shell plane. In addition is a substantial section of the fuselage shell perpendicular to the plane the hull shell acting forces, which results from the pressure difference between cabin and environment surrendered, charged. About that In addition, the hull shell is occasionally knocks, so short-term and intensive forces, exposed. An example of one such impact is a rubber shred of a shredded on landing Tire, which hits the hull shell at high speed.

Such impacts in such fuselage shells made of fiber composite material are many Trigger for damage initiation in the fuselage shell. This results in a power flow starting from the impact along the fuselage shell over the T-Stringer foot in the web section of the T-stringer inside. Especially in the lateral connection areas of the T-stringer footing and the foot area of the T-stringer, which is directly below the web section of the T-Stringers is, it comes for a short time to very large voltage spikes in the resin matrix. The result is a brittle fracture of the resin matrix in these Access areas. Then solve yourself the T-stringer from the hull shell and it comes to the catastrophic collapse of this.

task The object of the present invention is to provide an improved connection structure between a structural component and a stringer, wherein in particular a detachment the stringer of the structural component under the influence of impacts prevented shall be.

According to the invention this Task by a connection structure with the features of the claim 1 or by a method for producing a connection structure solved with the features of claim 11.

Accordingly, a Connection structure for an aerospace vehicle with a structural component and a Stringer, which over Attachment areas connected to the structural component is provided. In at least one of the attachment areas is a high impact material for one loka le increase the energy absorption capacity of the introduced at least one connection area.

Further becomes a method of manufacturing such a connection structure for a Air or spacecraft provided. The process steps become briefly described below. First, a structural component and a stringer, which over Connection areas are connected to each other, provided. Then it is a high impact Material in at least one of the attachment areas for a local increase the energy absorption capacity the introduced at least one connection area. An assembly of the structural component and the stringer over The connection areas can be before or after the introduction of the high impact resistant Materials are made.

The The idea underlying the present invention is that that resulting from the impact voltage peaks in the Bonding areas between hull shell and stringer from a high-impact material attenuated become. This is no longer the failure of the resin matrix or the connection between structural component and stringer. Accordingly, can by means of the invention advantageously a release of the stringer from the fuselage shell for example, as a result of an impact and thus the catastrophic Collapse of the hull shell can be prevented. Thus, a more stable and thus created a safer connection structure.

In the dependent claims find advantageous embodiments and improvements of Invention.

Under a "structural component" are in this patent application especially flat trained components, such as fuselage shells, wing shells or rudder cups, to understand.

High impact materials In the present application, such materials are a clear one higher Energy capability have as epoxy resin. With "energy receptivity" is the absorption meant mechanical work, without causing the failure of the high-impact material comes.

Under "Assemble" is in this application any joining to understand the meaning of the DIN standard "joining", where in particular laying, nesting, riveting, screwing, Sew on and Sticking in question.

According to one preferred embodiment of the invention is the high impact material designed as a thermoplastic material. With "thermoplastic material" in this application is a material meant, which consists of 100% thermoplastic, so for example Polyethylene and / or polyamide, consists. Under "thermoplastic material" are in this application but also Mixtures (these are also called modified matrix) of resin, especially epoxy resin, plastic fibers, and thermoplastics to understand. The thermoplastic content of thermoplastics in thermoplastic material is subsequently in percent by weight, ie based on the total weight the thermoplastic material consisting of plastic fibers and / or Resin and / or thermoplastic, indicated.

According to one Further preferred embodiment of the invention, the structural component a fiber composite material and / or the stringer a fiber composite material on. Fiber composites are because of their low weight at high strength in aerospace preference. alternative but can also be provided that, for example, the structural component made of metal, in particular of an aluminum alloy and only the stringer has a fiber composite material. Of course Only the stringer made of metal, in particular an aluminum alloy, be manufactured and the structural component of a fiber composite material exhibit. The fiber composites of the stringer and the structural component can have the same or different compositions. These activities allow an optimization of the connection structure in terms of strength and weight.

According to one preferred embodiment of the invention comprises the thermoplastic material a higher one Thermoplastic component than the respective fiber composites. This results in a higher energy absorption capacity in certain connection areas.

Under an "attachment area" is present here Understand area in which the stringer with the structural component connected is. Multiple areas arise when an area the high impact Material has and another area of this high impact material does not have.

To a further preferred embodiment of the invention the thermoplastic content of the thermoplastic material is between 5% and 100%, in particular between 50% and 80%, furthermore preferred between 60% and 70%. Such a thermoplastic fraction is in relation to the Energy capability optimal, while still a sufficient strength, so maximum Tensile, compressive and shear stress in the connection areas, which the thermoplastic material, is guaranteed.

at a further preferred embodiment of the invention, the stringer a foot section, in which he rests on the skin shell, and / or a bridge section which is aligned substantially perpendicular to the skin shell is. On the one hand, such stringers work well on flat structural components on the other hand, fasten and stiffen the structural component sufficiently.

Prefers is the thermoplastic material in the region of the foot section, in particular in Area of the footbridge leading away from the web portion, and / or in the region of the web section. Under "in the field" are here preferably a few centimeters, in particular a distance of 0 cm to 5 cm from to understand the web portion or the ends of the foot section. At a Impact in the fuselage shell, it comes to a power flow of the Level of the fuselage shell first in the end areas of the foot sections of the stringer, through the foot sections through and into the bridge section. The power flow changes several times his direction, taking it in the places of change of direction to increased Burdens comes. Therefore it is purposeful the Stringer straight in provide these areas with thermoplastic material for increased energy absorption to provide in these areas.

According to one further preferred embodiment The invention relates to the thermoplastic material between the foot section and the structural component. Such a local contribution of the Thermoplastic material leaves realize production technology easily.

According to a preferred embodiment, the thermoplastic material is formed as a sewing thread, in particular as a thermoplastic thread. A "thermoplastic thread" in this application is understood to mean a thread which consists of 100% thermoplastic. Such a sewing is fertigungs technically rationally feasible and allows a targeted introduction of the thermoplastic material in the connection structure. Experimentally, it has been determined that the thermoplastic fibers do not dissolve under the action of pressure or heat on the connection structure, in particular during the curing of the fiber composite connection structure.

Preferably forms the sewing thread a seam, which in the longitudinal direction of the stringer and the Stringerfuß sewn to the structural component. from that results in ease of manufacture with favorable power flow.

at a preferred embodiment connects the sewing thread the foot section, in particular in its end region and / or in the region of the web section, with the structural component. This arrangement is related to the power flow resulting from a strike even cheaper.

at a further preferred embodiment the invention is the thermoplastic material as a textile fabric, Fiber scrim and / or crosslinked thermoplastic grains formed. Especially at Connecting structures made of fiber composite materials can be so trained thermoplastic materials very easy in the fiber fabric of the structural component or the stringer and thus efficiently to process. Furthermore, a good bond between the thermoplastic material and the fiber layers of the structural component and / or the stringer achieved.

Preferably the stringer is designed as a T, Z, C, L or Ω stringer. Depending on the load case let yourself thus one for a particular application will provide optimal form of the stringer.

According to one Another preferred embodiment of the invention is the structural component designed as a skin shell, in particular fuselage shell of the aircraft.

at a further preferred embodiment of the invention, the first and / or the second fiber composite material CFRP, in particular CFRP prepreg material, based on or based on semi-finished textile products, such as woven, laid, etc. CFRP has a high strength at low Weight up. CRP prepreg material is about it also easy to process.

According to one Further preferred embodiment of the invention are fastening means provided, in particular screws or rivets, for connecting the Stringers with the structural component.

Additionally or alternatively to a fastening of the stringer to the structural component by means of the resin matrix and / or the high-impact-resistant material, fastening means be provided, which absorb more energy from the impact can.

According to one further preferred embodiment of the method according to the invention is the arrangement consisting of structural component, stringer and connection areas by pressure and / or heat hardened to form the connection structure. Accordingly, the structural component, the stringer and the attachment areas in dry or wet State joined together and subsequently hardened.

According to one further preferred improvement of the method according to the invention a resin matrix is introduced into the structural member and the stringer. For the Case that the structural component and / or the stringer as a dry Semi-finished fiber must be provided in the course of the procedure Preparation of the connection structure introduced a resin matrix become.

Under "dry" fibers are in this Application to understand yet impregnated with resin fibers. On the other hand are already in with "wet" fibers Resin soaked but not yet cured Meant fibers. Furthermore, under "semi-finished fiber" especially fiber scrims, in particular Unidirectional fiber fabric, tissue or fiber mats to understand.

According to one preferred embodiment the method according to the invention is the structural component or the stringer as a semi-finished fiber, Prepreg material, at least partially cured fiber composite material provided. There is consequently a large number of possible combinations with regard to the materials used to form the structural component and / or the stringer.

For example can dry fiber scrims with already hardened web sections of stringers combined, with the stringer feet of, for example, prepreg material be provided.

According to one further preferred embodiment of the method according to the invention this includes a hand lay, prepreg, transfer molding and / or vacuum infusion process on. For the case that the structural component and / or the stringer dry be provided, it may be advantageous in terms of manufacturing technology the resin matrix by Vakuuminfusionsverfahren in the Fasergelege contribute.

The invention will be described below with reference to exemplary embodiments with reference to FIGS attached figures of the drawing explained in more detail.

From the figures shows:

1 a process state in the manufacture of a connection structure according to an embodiment of the present invention, wherein thermoplastic material is arranged over a large area between a skin shell and a stringer;

2 the connection structure, which according to the method of 1 is made;

3 a process state in the production of a connection structure according to another embodiment of the present invention, wherein the thermoplastic material is introduced as a sewing thread; and

4 the connection structure, which according to the method of 3 is made.

In all figures of the drawing are the same or functionally identical elements - if nothing else is indicated - with each have been given the same reference numerals.

1 shows a laminating device 1 which a contour 2 having. The contour 2 is shaping for a skin shell 3 , For example, a hull shell of an aircraft, wherein the skin shell is preferably composed of not yet cured layers of CFRP material.

An applicator 4 wears a thermoplastic material 5 on the skin shell 3 on. The thermoplastic material 5 in this embodiment, by weight percent, preferably has a composition of 40% polyethylene and 60% epoxy resin.

The application of the thermoplastic material 5 takes place along several, preferably three parallel, connection areas 8th . 9 and 10 , The thermoplastic material 5 is applied here as a powder. Equally, however, it would also be possible to apply fiber layers of thermoplastic material and / or to overlap them with the fibers of the skin shell. Subsequently, T-stringer 11 . 12 and 13 by means of a depositing device 14 on the skin shell 3 on the connection areas 8th . 9 . 10 stored.

The T-Stringer 11 . 12 and 13 are also made of CFRP material and are only partially cured. The T-Stringer 11 . 12 and 13 be with her foot 16 on the skin shell 3 discontinued, in which case a web section 17 perpendicular to the foot 16 and thus to the skin shell 3 extends.

After fitting the skin shell 3 with the T-stringers 11 . 12 . 13 , this arrangement becomes under pressure and heat to the connection structure 20 , as in 2 shown, cured.

Out 2 it can be seen that the stringer 13 essentially of two L-shaped layers CFK 21 and 22 is trained. The layers 21 . 22 subdivide again into many layers of fiber fabric (not shown here). A gusset 23 , typically a strand of fibers, fills one of the layers 21 . 22 unfilled space on.

The layers 21 . 22 are each on one leg 24 . 25 cohesively connected to each other and form the web section 17 out.

The two other thighs 28 . 29 extend in opposite directions and together form the foot 16 out. The thigh 28 . 29 each have toes at their ends 30 . 31 on which to the skin shell 3 flattened out.

Furthermore, in 2 the connection areas 8th . 9 . 10 . 34 . 35 shown. The connection areas 8th . 9 . 10 each have the thermoplastic material 5 on. The connection areas 8th and 10 are each at the end of the thighs 28 . 29 under the toes 30 . 31 arranged. The connection area 9 is below the gusset 23 educated.

Further, the foot is 16 the stringer 13 about the connection areas 34 . 35 with the skin shell 3 connected. In these areas, the connection takes place by means of gluing the resin matrix in the layers 21 . 22 with the resin matrix in the skin layer 3 ,

For example, an impact works in the point 36 on the skin shell 3 That's how it turns out 36 resulting force flow over the connection areas 8th . 9 . 10 . 34 . 35 in the stringer 13 initiated. In the connection areas 8th . 10 the power flow changes its direction from the skin shell 3 out in the stringer 13 into, and in the connection area 9 the deflection of the power flow takes place from the foot 16 in the bridge section 17 into it. So at the points where there is a significant change in direction of the power flow, namely in the connection areas 8th . 9 and 10 , According to the invention, the thermoplastic material is preferably provided. It is by means of the invention thus an energy absorption or damping in these connection areas 8th . 9 . 10 achieved.

The connection areas 34 . 35 have a lower energy absorption capacity than the attachment areas 8th . 9 . 10 , but preferably have a higher tensile strength.

3 also shows the laminator 1 and the contour 2 , The contour 2 is thereby shaping a skin shell 50 as a dry fiber fabric on the contour 2 rests. T-stringer 51 . 52 . 53 . 54 are on the skin shell 50 arranged. The T-Stringer 51 ... 54 are also present as a dry, especially interwoven, fiber fabric.

Subsequently, the T-stringer 51 ... 54 by means of a sewing device 56 that is a thermoplastic material 55 provides with the skin shell 50 sutured. This is the foot 57 the stringer 51 in the longitudinal direction and adjacent to the web section 58 or the tiptoe 59 . 60 with the skin shell 50 sutured. As sewing threads 61a ... 61d Here, a thermoplastic threads are used, which preferably consist of 100% polyethylene.

Subsequently, the arrangement consisting of the skin shell 50 and the T-stringers 51 ... 54 preferably impregnated in a vacuum infusion process with a matrix, in particular an epoxy resin matrix. In a further process step, the resin-impregnated arrangement by heat and pressure, for example in an autoclave, to the in 4 illustrated connection structure 63 hardened.

Components that are not described further correspond to those from 2 , The sewing threads 61a and 61d fix the tiptoes 59 respectively. 60 on the skin shell 50 and thus form a first and second connection area. The sewing threads 61b and 61c extend right and left side of the web section 58 For example, run crosswise through the foot 57 and the skin shell 50 through and thus form a third and fourth connection area. The first to fourth connection areas serve to absorb energy, for example as a result of an impact.

There are also connection areas 64a ... 64d provided, with the foot 57 by means of resin with the skin shell 50 is glued. These connection areas 64a ... 64d preferably have one opposite the connection areas 61a ... 61d lower energy absorption capacity, but have a higher maximum tensile strength (N / mm ² ), so the voltage, after exceeding it to a failure in these connection areas 64a ... 64d comes.

A detachment of the stringer 13 . 58 from the skin shells 3 . 50 as a result of an impact 36 can thus be effectively prevented.

The Invention is not limited to those shown in the figures, special Connection structure or on the process for producing a limited such connection structure.

The individual sequence of individual method steps of the method according to the invention can be changed in a variety of ways. The design of the individual process steps themselves can also be modified. For example, in the in 3 instead of a dry stringer, a wet stringer, or even a stringer with a cured land portion and wet foot.

Farther is the geometry of the skin shell and the stringer in a variety of ways and modifiable. Instead of T-stringers, Ω-stringer can also be used, those in the area of their foot sections connected to a skin shell. With "Stringer" is any kind of stiffening element, ie Also, for example, a bulkhead, meant.

It is also conceivable that only a connection area between Stringer and structural component is provided, this entire Connection area is provided with thermoplastic material.

1

laminating

2

contour

3

skin shell

4

applicator

5

Thermoplastic Material

8th

connecting region

9

connecting region

10

connecting region

11

Stringer

12

Stringer

13

Stringer

14

laying device

15

foot section

17

web section

20

connecting structure

21

location

22

location

23

gore

24

leg

25

leg

28

leg

29

leg

30

toe

31

toe

34

connecting region

35

connecting region

36

A hit

50

skin shell

51

T-stringer

52

T-stringer

53

T-stringer

54

T-stringer

55

Thermoplastic Material

56

sewing equipment

57

foot section

58

web section

59

toe

60

toe

61a ... 61d

sewing threads

63

connecting structure

64a ... 64d

connecting regions

Claims (19)

Connection structure ( 20 ; 63 ) for an aircraft or spacecraft, with a structural component ( 3 ; 50 ) and a stringer ( 11 . 12 . 13 ; 51 ... 54 ), which via connection areas ( 8th . 9 . 10 . 34 . 35 ; 61a ... 61d . 64a ... 64d ) with the structural component ( 3 ; 50 ), characterized in that in at least one of the attachment areas ( 8th . 9 . 10 . 34 . 35 ; 61a ... 61d . 64a ... 64d ) a high impact material ( 5 ; 55 ) for a local increase in the energy absorption capacity of the at least one connection region ( 8th . 9 . 10 ; 61a ... 61d ) is introduced. Connecting structure according to claim 1, characterized in that the high-impact-resistant material ( 5 ; 55 ) is formed as a thermoplastic material. Connecting structure according to claim 1 or 2, characterized in that the structural component ( 3 ; 50 ) a fiber composite material and / or the stringer ( 11 . 12 . 13 ; 51 ... 54 ) comprises a fiber composite material. Connecting structure according to Claim 3, characterized that the thermoplastic material has a higher thermoplastic content than having the respective fiber composites. Connecting structure according to at least one of claims 2 to 4, characterized in that the thermoplastic part of the thermoplastic material between 5% and 100%, in particular between 50% and 80%. Connecting structure according to at least one of the preceding claims, characterized in that the stringer ( 11 . 12 . 13 ; 51 ... 54 ) a foot section ( 15 ; 57 ) for a support on the structural component ( 3 ; 50 ) and / or a bridge section ( 17 ; 58 ) which is substantially perpendicular to the structural component ( 3 ; 50 ) is aligned. Connecting structure according to claim 6, characterized in that the high-impact-resistant material ( 5 ; 55 ) in the area of the foot section ( 15 ; 57 ), in particular in the end region pointing away from the web section ( 30 . 31 ; 59 . 60 ) of the foot section ( 15 ; 57 ) and / or in which at the web section ( 17 ; 58 ) adjacent area of the foot section ( 15 ; 57 ) is arranged. Connecting structure according to at least one of the preceding claims, characterized in that the high-impact-resistant material ( 5 ; 55 ) as sewing thread ( 61a ... 61d ), in particular as a thermoplastic thread, is formed. Connecting structure according to claim 8, characterized in that the sewing thread ( 61a ... 61d ) forms a seam, which in the longitudinal direction of the stringer ( 51 ... 54 ) and the foot section ( 57 ) of the stringer ( 51 ... 54 ) with the structural component ( 50 Sewn. Connecting structure according to at least one of claims 2 to 7, characterized in that the thermoplastic material as a textile Fabrics, Fasergelege and / or crosslinked thermoplastic grains is formed. Method for producing a connection structure ( 20 ; 63 ) for an aircraft or spacecraft, comprising the following steps: providing a structural component ( 3 ; 50 ) and a stringer ( 11 . 12 . 13 ; 51 ... 54 ), which are connected via connection areas ( 8th . 9 . 10 . 34 . 35 ; 61a ... 61d . 64a ... 64d ) are connectable to each other; Introducing a highly impact-resistant material into at least one of the attachment areas ( 8th . 9 . 10 . 34 . 35 ; 61a ... 61d . 64a ... 64d ) for a local increase in the energy absorption capacity of the at least one connection region ( 8th . 9 . 10 ; 61a ... 61d ); and assembling the structural component ( 3 ; 50 ) and the stringer ( 11 . 12 . 13 ; 51 ... 54 ) via the connection areas ( 8th . 9 . 10 . 34 . 35 ; 61a ... 61d . 64a ... 64d ). A method according to claim 11, characterized in that the high impact material ( 5 ; 55 ) is formed as a thermoplastic material. A method according to claim 11 or 12, characterized in that the arrangement consisting of the structural component ( 3 ; 50 ), the stringer ( 11 . 12 . 13 ; 51 ... 54 ) and the connection areas ( 8th . 9 . 10 . 34 . 35 ; 61a ... 61d . 64a ... 64d ) by means of pressure and / or heat to form the connection structure ( 20 ; 63 ) is cured. Method according to at least one of claims 11 to 13, characterized in that a resin matrix, in particular an epoxy resin, in the structural component ( 3 ; 50 ) and the stringer ( 11 . 12 . 13 ; 51 ... 54 ) is introduced. Method according to at least one of the preceding claims 11 to 14, characterized in that the structural component ( 3 ; 50 ) and / or the stringer ( 11 . 12 . 13 ; 51 ... 54 ) is provided as semi-finished fiber product, prepreg material, at least partially cured fiber composite material. Method according to at least one of claims 12 to 15, characterized in that the thermoplastic part of the thermoplastic material by weight percent between 5% and 100%, especially between 50% and 80%, chosen becomes. Method according to at least one of claims 11 to 16, characterized in that the high-impact-resistant material ( 5 ; 55 ) between a foot section ( 16 ; 57 ) of the stringer ( 11 . 12 . 13 ; 51 ... 54 ) and the structural component ( 3 ; 50 ) is arranged. Method according to at least one of claims 11 to 17, characterized in that the stringer ( 11 . 12 . 13 ; 51 ... 54 ) with the structural component ( 3 ; 50 ) by means of a sewing thread ( 61a ... 61d ) from the high impact resistant material ( 5 ; 55 ), in particular with a thermoplastic thread, is sewn. Method according to at least one of claims 11 to 18, characterized in that the high-impact-resistant material ( 5 ; 55 ) as a textile fabric, fiber fabric, powder and / or aerosol is introduced.