EP3860835A2

EP3860835A2 - Semi-finished product and method for producing a structural component

Info

Publication number: EP3860835A2
Application number: EP19779842.4A
Authority: EP
Inventors: Julian Kuntz
Original assignee: Premium Aerotec GmbH
Current assignee: Premium Aerotec GmbH
Priority date: 2018-10-04
Filing date: 2019-09-26
Publication date: 2021-08-11
Also published as: US20210370620A1; DE102018217018A1; WO2020069978A2; WO2020069978A3

Abstract

The present invention relates to a semi-finished product (1) for producing a structural component (B), comprising a plurality of prepreg strips (2), each of which comprises unidirectionally arranged reinforcement fibers (21) embedded in a thermoplastic matrix material (20), and a plurality of connecting strands (3) containing a thermoplastic plastic material (30). The prepreg strips (2) and the connecting strands (3) are either connected to form a textile fabric structure (4) or the prepreg strips (2) are arranged to form a multi-axial scrim (6), wherein individual layers (60) of the scrim (6) are connected by the connecting strands (3). The invention further relates to a method for producing a curved structural component (B) from such a semi-finished product (1).

Description

Semi-finished product and method for producing a structural component

The present invention relates to a semi-finished product and a method for producing a structural component, in particular a structural component, which has a curved or double-curved shape or shape.

Come in particular in the field of aerospace engineering

Structural components made of fiber composite material are used, which have a dome-shaped or dome-shaped or otherwise spherical shape that is curved in at least two directions. Such components are used in aircraft construction e.g. used as a pressure frame or as a fuselage shell.

To produce such multi-curved structural components

typically first a plurality of mat-shaped semi-finished fiber products are stacked to form a laminate or layer structure. The semi-finished fiber products can be present as fiber mats pre-impregnated with a matrix material. The laminate structure formed is then deformed and the matrix material is hardened. US 2005/00351 15 A1 describe a process for the production of

Fiber composite components, wherein a layer structure, which has reinforcing fiber layers embedded in thermoplastic matrix material, between

Heating mats added and heated inductively to a forming temperature. In a closed cavity of a pressing tool, the layer structure is formed together with the heating mats using a pressure fluid. A similar process is described in US 5,591,369 A. DE 10 2010 050 740 A1 describes a method for producing a

Structural component, wherein a plurality of semifinished layers from one

fiber-reinforced thermoplastic material are stacked and selectively connected to each other to fix a position of the semifinished layers relative to each other. Wrinkling during subsequent press forming is to be avoided by the type of connection.

It is an object of the present invention to provide a semifinished product and a method for producing a structural component made of a fiber-reinforced thermoplastic material, with which the formation of wrinkles during forming is further reduced.

This object is achieved by the subject matter of the independent claims. According to a first aspect of the invention, a semifinished product is provided for producing a structural component. The semifinished product comprises a multiplicity of prepreg tapes which extend along one another and each have unidirectionally arranged reinforcing fibers embedded in a thermoplastic matrix material and a multiplicity of connecting strands comprising a thermoplastic material. The connecting strands and the

Prepreg tapes are connected to form a textile fabric in which each of the connecting strands crosses several of the prepreg tapes. The

Connecting strands and the prepreg bands are in a first end region of the Flat structure and a second end region of the flat structure lying opposite to it, each along a connecting line

cohesively connected. One idea on which the invention is based is to provide a semifinished product in the form of a textile fabric which is formed from prepreg tapes with unidirectional fibers and connecting strands which have a thermoplastic material. In particular, the thermoplastic material of the connecting strands can be the same thermoplastic material as the matrix material contained in the prepreg tapes or at least have a similar composition. The textile structure, i.e. a structure made up of intersecting strands, offers the advantage that the semi-finished product is anisotropic

Has deformation properties. In particular, the textile structure allows the prepreg tapes to slide along one another, which prevents wrinkling when deforming. The formation of wrinkles is further prevented by the fact that a cohesive connection of the strands, that is to say a cohesive connection between prepreg tapes and thermoplastic connecting strands, only along connecting lines lying opposite one another

is provided, the prepreg strips and the connecting strands being able to slide against one another at the other crossing points or not being connected. The unidirectional thermoplastic prepreg tapes are elongated, single-ply tape material, in which continuous, unidirectional reinforcing fibers are embedded in a thermoplastic matrix material. Prepreg tapes of this type have the advantage that they are easily deformable but are not very susceptible to the formation of undulations. In contrast to semi-finished products, which consist purely of woven reinforcing fibers, no subsequent infiltration is required with the semi-finished product according to the invention Matrix material more to produce a structural component from the semi-finished product.

According to a further aspect of the invention, a semifinished product is provided for producing a structural component. The semi-finished product includes a variety of

Prepreg tapes, each in a thermoplastic matrix material

have embedded, unidirectionally arranged reinforcing fibers. A variety of thermoplastic materials are also optional

containing connecting strands provided. The prepreg tapes are arranged to form a multiaxial fabric which comprises a plurality of layers of prepreg tapes lying one above the other, the prepreg tapes running parallel to one another within one layer, and the layers being connected at individual points relative to one another, in particular sewn, knitted, woven, welded or through another textile process connected, preferably by means of the connecting strands.

According to this aspect of the invention, a multi-layer semifinished product is provided, the individual layers being formed from parallel prepreg strips and the individual layers being connected only selectively by the connecting strands. For example, connection points can be provided along parallel lines. Due to the only selective connection of the layers and the parallel

Extension of the prepreg strips and thus of the reinforcing fibers within the individual layers, the individual layers can slide relative to one another and the fibers within the individual layers can slide relative to one another, as a result of which one

Wrinkle formation is prevented. The advantages mentioned above for the use of prepreg tapes with thermoplastic material also apply analogously to this aspect of the invention. The semifinished products described in particular enable efficient storage of flat semifinished product layers. This eliminates the need to store and fix individual prepreg tapes to form a flat layer. According to a further aspect of the invention, a method for producing a structural component having a curved shape is provided. According to this method, a layer structure is first formed from a plurality of layers, the layers each having at least one semi-finished product which is designed as described above. The layers can optionally be on one

Connection point, which is located in the area of an apex of the arched shape to be produced, can be thermoplastic connected, e.g. by welding, in particular ultrasonic welding. So there is a discrete, e.g. punctiform material connection of the layers of the layer structure is produced at a point at which no or only slight relative movements of the individual layers to one another occur during the forming in order to produce the curved shape. In a further step, the

Layer structure in the curved shape at a forming temperature that is less than a melting point of the thermoplastic materials of the semi-finished product. After the forming, the formed layer structure is heated to one

Temperature that is greater than the melting point of the thermoplastic materials of the semi-finished product, that is, greater than the melting point of the thermoplastic matrix material of the prepreg tapes and greater than the melting point of the thermoplastic material of the connecting strands of the semi-finished product. Finally, the layer structure with application of a

Compression pressure consolidated and under this pressure back to one

Cooled solidification temperature, which is less than the melting point of the thermoplastic materials of the semi-finished product. Another idea of the invention is therefore to create wrinkles

reduce by the deformation of the layer structure takes place at a temperature which is lower than the melting point of the thermoplastic materials of the semi-finished product. Since the thermoplastic materials are still solid during the forming process, the layers of the layer structure stick together outside of the optional ones

Connection point not yet, so that the layers can still slide against one another, in particular if the layers also shift differently due to different fiber directions during the forming process. In this way, the individual prepreg tapes of a respective layer itself and the individual layers can slide relative to one another, which leads to wrinkling of the

Prevents reinforcement fibers. By fixing the layers or layers relative to one another in an area of the layer structure which after the forming contains an apex of the curved shape of the structural component, sliding of the layers to one another in more deformed areas is facilitated.

The mechanical strength of the components is improved by reducing the formation of folds. Thanks to the textile structure made of prepreg tapes and

Connecting strands, which each have one, preferably the same thermoplastic material, can be produced in a very simple and quick manner after the shaping, a large flat component.

Advantageous refinements and developments result from the subclaims which refer back to the independent claims in conjunction with the description.

The prepreg tapes can in particular have a width between 3 mm and 15 mm. In particular, it can also be provided that a width is between 0.001 percent and 5 percent of a length of the prepreg edges. Are general the prepreg tapes are narrow, which further improves the deformability of the semi-finished product.

According to one embodiment of the semi-finished product, it is provided that the

Prepreg tapes extend in a first direction and the

Connecting strands extend in a second direction running transversely to the first direction, and a first prepreg tape that is outermost in relation to the second direction and an extreme second prepreg tape that is located opposite to the first prepreg tape, in order to form the connecting lines each integrally with the Connecting strands are connected. According to this embodiment, the connecting lines run along opposite, outermost prepreg bands of the semi-finished textile product. This prevents fraying or disintegration of the semi-finished product, while the sliding of the individual strips relative to one another is prevented as little as possible.

According to a further embodiment of the semi-finished product, the prepreg strips and the connecting strands are woven together. Accordingly, the prepreg tapes run parallel to each other, e.g. in a first direction, and the connecting strands extend transversely to the prepreg bands, e.g. in a second direction, and also run parallel to each other. For example, the prepreg tapes can be provided as warp strands and the connecting strands as weft strands or vice versa. The are optional

Connecting strands and the prepreg tapes are woven in an atlas weave, in which the weft strand passes under a warp strand and then over more than two warp strands. The training of the textile

Fabric by weaving prepreg tapes and

Connecting rods offers the particular advantage that within the The reinforcing fibers are approximately parallel to one another. Furthermore, weaving can be carried out automatically in a simple manner.

According to a further embodiment, the prepreg strips and the

Interconnecting strands.

According to a further embodiment of the semi-finished product, the

Connecting strands each have a first end section and opposite to this second end section, the first and second end sections each projecting beyond the connecting lines. Accordingly, the connecting strands form protrusions or a kind of tabs which protrude over an edge or edge area of the fabric. These tabs can be used for cohesive coupling to other semi-finished products of the same or similar construction, which facilitates the processing of the semi-finished product.

According to a further embodiment of the semifinished product

Connecting strands as consisting of the thermoplastic material

Foil tapes or as threads made of the thermoplastic material. Ribbons, i.e. strands with flat, rectangular cross sections, have a small cross section thickness, so that a very thin semi-finished product can be realized. Threads, i.e. strands with several filaments twisted into an approximately circular cross section, offer the advantage of a larger one

mechanical strength. The connecting strands are optionally made of thermoplastic

Plastic material, preferably the thermoplastic matrix material of the prepreg tapes. As a result, the connecting strands loosen when the semi-finished product is heated to a temperature greater than the melting temperature of the thermoplastic materials to a certain extent and also improve the cohesion between the reinforcing fibers.

According to one embodiment of the method, it is provided that the individual layers of the layer structure are each formed from a plurality of semi-finished products in which the connecting strands protrude beyond the connecting lines, as was described above. In particular, at least the first end sections of the connecting strands of a first semifinished product

Prepreg tapes of a respective further semi-finished product thermoplastic bonded. Optionally, the second end sections of the

Connecting strands of the further semi-finished product are connected to prepreg tapes of the first semi-finished product in a thermoplastic manner. This makes it easy to produce large flat layers. A welding process, e.g. Ultrasonic welding can be used.

According to a further embodiment of the method it can be provided that the layer structure is formed in such a way that the prepreg strips extend in different layers in different directions. For example, the layers are stacked one on top of the other in such a way that the prepreg strips of two adjacent layers or layers each extend in different directions. The reinforcing fibers thus also extend in different layers in different directions, which improves the mechanical strength of the structural component.

According to a further embodiment of the method, the layer structure is formed by sequentially stacking the layers on a flat storage surface, and the forming is carried out in a further step, for example in a cavity Molding tool, wherein the cavity is formed by a molded part with a contour surface corresponding to the curved shape of the structural component and a flat contact part. Stacking on a flat surface has the advantage that a large number of layers can be deposited quickly, and the risk of wrinkles is low. The forming takes place in a separate (press) forming step.

According to a further embodiment of the method, the layer structure is formed by sequential stacking of the layers on a curved storage surface and thereby simultaneously deformed into the curved shape, whereby the

Storage area is formed a contour surface of a molded part of a mold corresponding to the curved shape of the structural component, the molded tool additionally having a flat contact part for forming a cavity with the molded part. Each layer is placed on a curved surface and thereby at least partially already formed into the desired shape. This offers the advantage that the individual layers do not have to slide against one another, or only slide to a small extent, which further reduces the risk of wrinkles. It can optionally be provided that layers of the layer structure deposited on the curved contour surface of the molded part are in addition to those in the area of the

Optional connection point located at the apex at further points

Connection points are connected thermoplastic. This fixes the layers in their position.

According to a further embodiment of the method, it is provided that the layer structure is heated in the cavity of the molding tool. if the Layers have already been deposited on the molded part, the cavity is first closed by the deposit part, thereby compacting the individual layers.

According to a further embodiment of the method, the molded part of the molding tool is designed as a flat, first molded sheet, the contact part being designed as a flat, second molded sheet. The molded part and the plant part are therefore each designed as flat, curved metal plates. Compared to solid presses, the molded parts have a low heat capacity. As a result, the cavity can be heated up quickly and with little energy expenditure.

The molded part can also be designed as a partially solid form, e.g. with a surface section, which forms the contour surface, and with a base section, which is designed as a stiffening structure and supports the surface section.

According to one embodiment, a magnetic field is generated to apply the compression pressure by means of a magnetic device, which magnetic field is coupled into a magnetizable material assigned to the first shaped plate and / or into a magnetizable material assigned to the second shaped plate in such a way that the layer structure is subjected to the compression pressure through the shaped plates . In particular, a magnetic field directed transversely to the contour surface is generated. Accordingly, the compression pressure is generated by means of a magnetic force which, for example, can act directly on the shaped sheets, e.g. if the first and / or the second shaped sheet is formed from a magnetizable metal material and the magnetizable material is assigned to the respective shaped sheet in this way. Alternatively, the

Magnet device also coupled to the mold plates magnetizable elements have as a magnetic material, which press the molded sheets relative to one another by the action of the magnetic field. Due to their planar extent, the shaped sheets allow the formation of a shape extending through the cavity in which the layer structure is located

Magnetic field. On the one hand, this results in a very even pressure distribution. This also has the advantage that the shaped sheets can be made relatively thin, which reduces the tool costs. The force for compressing the mold halves can act in particular through the mold halves and the component. This is particularly advantageous for large, flat components.

According to a further embodiment of the method, the molding tool for heating and cooling or consolidating is placed on one mold half, the compression pressure being applied by the molding tool during cooling. The mold half can in particular serve as a kind of support for the

Serve mold, which is particularly advantageous when using shaped sheets. Furthermore, the mold half can also serve as a heat sink.

According to a further embodiment, it is provided that the mold for cooling or consolidating in one by two mold halves

Arranged cavity formed and the compression pressure is applied through the mold halves. Accordingly, it is provided that

Molding tool, in the cavity of which the layer structure is accommodated, is pressed together between two mold halves adapted to an outer contour of the molding tool. In this way, the final desired curved shape of the structural component can be produced very precisely. The

Press tool also serves as a heat sink for cooling the layer structure. A heating of the layer composite in the cavity of the mold and one Cooling the layer composite in the cavity of a separate pressing tool speeds up the process and saves energy.

According to a further embodiment of the method, the layer structure is heated by inductive heating of the shaped sheets or by means of

Infrared radiation. Inductive heating, that is to say heating by generating alternating magnetic fields by means of an alternating electrical voltage, offers the advantage that the shaped plates themselves act as a heating device. This enables the cavity to be heated up efficiently. Infrared radiation can advantageously be generated with little design effort. Since the shaped sheets have a low heat capacity, both heating is by means of

Infrared radiation as well as inductive heating of the mold plates are suitable for generating rapid temperature changes in the cavity, which accelerates both the heating and the cooling of the layer structure.

According to a further embodiment, a vacuum is created in the cavity of the molding tool. In particular during the forming and / or to apply the compression pressure. By creating a vacuum in the cavity of the molding tool, air that may be present between or in the layers of the layer structure becomes from the layer structure

aspirated. This prevents pore formation in the structural component and thereby increases the mechanical strength of the structural component. Furthermore, the vacuum can be used at least partially to generate the compression pressure or the pressure for forming. This further speeds up the process.

In this context, a “curved component” or a “curved shape” is generally understood to mean a geometric body that has at least a first one

Surface and a second surface oriented opposite to this has, wherein the first and the second surface are each curved in at least two directions. In particular, this cannot include geometries that can be developed on one plane. For example, a domed body is understood here to mean an at least partially dome-shaped, spherical, parabolic or bowl-shaped body.

A vertex of the arched shape of the component can, for example, by the center of gravity of one of the body forming the arched shape

Surfaces. In particular, the vertex can be on a

Intersection of symmetry lines of the curved shape.

With regard to directions and axes, in particular directions and axes, which relate to the course of physical structures, a course of an axis, a direction or a structure “along” another axis, direction or structure is understood here to mean that these, in particular the tangents resulting in a respective location of the structures at an angle of less than or equal to 45 degrees, preferably less than 30 degrees and

particularly preferably run parallel to one another. With regard to directions and axes, in particular to directions and axes, which relate to the course of physical structures, a course of an axis, a direction or a structure “transverse” to another axis, direction or structure is understood here to mean that these, in particular, the tangents resulting in a respective location of the structures each run at an angle of greater than or equal to 45 degrees, preferably greater than or equal to 60 degrees and particularly preferably perpendicular to one another. Reinforcing fibers herein may be generally filamentary or filamentary fibers, such as carbon, glass, ceramic, aramid, boron, mineral, natural, or plastic fibers, or mixtures thereof. A “melting point” or a “melting temperature” in relation to a thermoplastic material is understood here to mean a temperature above which the material is in a flowable, viscous state. Above the

Melting temperature can be a component made of thermoplastic material with another component made of thermoplastic material, which is also above the

Melting temperature is present, cohesively connected, in particular fused.

The invention is described below with reference to the figures of FIG

Drawings explained. From the figures show:

Fig. 1 is a plan view of a semi-finished product according to one

Embodiment of the present invention;

Fig. 2 is a plan view of a semi-finished product according to another

Embodiment of the present invention;

Fig. 3 is a schematic sectional view of a prepreg tape

Semi-finished product according to an embodiment of the present invention;

Fig. 4 is a schematic sectional view of a connecting strand

Semi-finished product according to an embodiment of the present invention; Fig. 5 is a schematic sectional view of a connecting strand

Semi-finished product according to a further embodiment of the present invention;

Fig. 6 is a plan view of a location for generating a

Layer structure, the layer being formed from two semi-finished products according to FIG. 1; Fig. 7 is a plan view of a location for generating a

Layer structure, which consists of several cut

Semi-finished products is formed according to an embodiment of the present invention; Fig. 8 is a plan view of the position of Fig. 7 after performing a

Cutting;

9 shows a schematic exploded view of a layer structure composed of several layers;

10 shows a plan view of a layer structure composed of several layers after the creation of an optional connection point in one step of a method according to an exemplary embodiment of the present invention;

Fig. 1 1 is a schematic sectional view of a layer structure

several layers according to one step of a process an embodiment of the present invention was generated on a flat surface;

Fig. 12 is a schematic sectional view of a layer structure from

a plurality of layers, which was generated in a step of a method according to an exemplary embodiment of the present invention on a curved storage surface;

13 shows a forming and heating of a layer structure in a cavity of a molding tool in steps of a method according to an exemplary embodiment of the present invention;

14 shows a consolidation of a layer structure accommodated in a cavity of a molding tool in a cavity of a

Press tool in one step of a method according to a

Embodiment of the present invention;

15 shows forming, heating and consolidation of a layer structure in a cavity of a molding tool in steps of a method according to an exemplary embodiment of the present invention;

16 shows a schematic partial sectional view of a semifinished product according to a further exemplary embodiment of the present invention; and

17 shows a structural component produced by means of a method according to an exemplary embodiment of the present invention. In the figures, the same reference numerals designate identical or functionally identical components, unless stated otherwise.

The figures 1, 2 and 16 each show a semi-finished product 1 for producing a

Structural component B. As shown in FIGS. 1, 2 and 16, the semifinished product has a multiplicity of prepreg strips 2 and a multiplicity of connecting strands 3.

3 shows an example of a schematic, interrupted sectional view of a prepreg tape 2. As can be seen in FIG. 3, the prepreg tape 2 has a plurality of reinforcing fibers 21 which extend in one direction or unidirectionally. The reinforcing fibers 21 can be present, for example, as fiber bundles. As further shown in FIG. 3, the reinforcing fibers 21 are in one

thermoplastic matrix material 20 embedded. As in particular in FIGS. 1, 2 and 16, the prepreg tapes 2 are realized as narrow, strip-shaped tapes. As shown in Fig. 3, the prepreg tapes 2 can have a width b2, e.g. in a range between 1 mm and 15 mm, and a length I2, e.g. have in a range between 0.5 m and 100 m.

The figures 4 and 5 show examples of possible configurations of the

Connecting strands 3. In particular, the connecting strands 3 can each consist of a thermoplastic material or have a thermoplastic material. 4 shows, by way of example, a reinforcing strand 3 in cross section, which is realized as a film strip 33 consisting of thermoplastic material 30. As shown by way of example in FIG. 4, the film strip 33 can be realized with a rectangular cross section. 5 shows, by way of example, a reinforcement strand 3 in cross section, which is designed as a thread 34 consisting of thermoplastic material 30. As shown schematically and by way of example in FIG. 5, the thread 34 can consist of several twisted filaments 35 may be formed, which form an approximately circular cross section of the thread 34. Optionally, the reinforcing strands 3 contain the same thermoplastic material that is used as the matrix material of the prepreg tapes.

The semi-finished product 1 shown by way of example in FIG. 1, the prepreg tapes 2 and the connecting strands 3 are woven together and thereby form a textile, single-layer sheet 4. As shown by way of example in FIG. 1, the connecting strands 3 run transversely to the prepreg strips 2, each of the

Connecting strands 3 crosses several of the prepreg strips 2. In particular, each connecting strand 3 runs in sections on opposite sides of the prepreg strips 2. The prepreg strips 2 run along one another and do not cross one another within the flat structure 4. In Fig. 1 are the

Connecting strands 3 shown as an example as foil strips 33.

As can be seen in FIG. 1, the prepreg tapes 2 extend in a first direction R1 and the connecting strands 3 extend in a second direction R2 running transverse to the first direction R1. In order to prevent fraying of the fabric, a first prepreg tape 2A which is outermost in relation to the second direction R2 and an extreme second prepreg tape 2B which is situated opposite to the first prepreg tape are integrally connected to the connecting strands 3 in FIG. 1. As shown by way of example in FIG. 1, the connecting strands 3 are in the region of a first end section 31 with the first prepreg tape 2A and in the region of a second end section 32, which is opposite to the first end section 31 with respect to the second direction R2 second prepreg tape 2A integrally connected. The first and the second prepreg tape 2A, 2B each define opposite edges of the textile fabric 4. As shown by way of example in FIG. 1, can in particular each of the connecting strands 3 with the first and the second prepreg tape 2A, 2B be integrally connected. In general, the connecting strands 3 and the prepreg strips 2 are integrally connected to one another in a first end region 41 of the flat structure 4 and in a second end region 42 of the flat structure 4 lying opposite this, along a connecting line 5A, 5B. In FIG. 1, the connecting lines 5A, 5B each run along the first direction R1 or along the first and second prepreg bands 2A, 2B. The cohesive connection can be produced, for example, by ultrasonic welding.

As further shown in FIG. 1, it can be provided that the first end section 31 of the connecting strands 3 protrudes or projects beyond the first prepreg band 2A and the second end section 32 of the connecting strands 3 extends beyond the second prepreg band 2B and thus, and thus forms a protruding tab. In general, it can be provided that the

End sections 31, 32 of the connecting strands 3 each protrude beyond the connecting lines 5A, 5B.

In the semifinished product 1 shown by way of example in FIG. 2, the prepreg strips 2 and the connecting strands 3 are intertwined and thereby form a textile, single-layer flat structure 4. As shown schematically in Fig. 2, the connecting strands 3 run transversely to the prepreg bands 2, each of the

Connecting strands 3 crosses several of the prepreg strips 2. In particular, each connecting strand 3 runs in sections on opposite sides of the prepreg strips 2. In FIG. 2, the connecting strands 3 are exemplary as

Foil tapes 33 shown. As shown by way of example in FIG. 2, the connecting strands 3 in the area of a first end section 31 and in the area of a second end section 32, which is opposite to the first end section 31 with respect to the second direction R2, are each materially bonded to one of the prepreg strips 2 connected. As a result, the connecting strands 3 and the prepreg strips 2 are integrally connected to one another in a first end region 41 of the flat structure 4 and in a second end region 42 of the flat structure 4 lying opposite to this, along a connecting line 5A, 5B. FIG. 2 shows, by way of example, that the connecting lines 5A, 5B each run along intersections of the prepreg strips 2 and the connecting strands 3 and obliquely to a longitudinal extent of the prepreg strips 2 and the connecting strips 3. The integral connection can, for example, by

Ultrasonic welding are generated. As further shown in FIG. 2, it can be provided that in one or more of the connecting strands 3, the first end section 31 via the first connecting line 5A and the second end section 32 via the second

Connection line 5B protrudes and thus forms a protruding tab. The in Figs. 1, 2 semi-finished products 3 shown by way of example allow the prepreg tapes to slide against one another due to their textile structure, thereby reducing the risk of wrinkles when the semi-finished product is deformed.

The semi-finished product 1 shown schematically and by way of example in FIG. 16 is constructed in several layers. The prepreg tapes 2 are arranged to form a surface-extending multiaxial fabric 6, which comprises a plurality of layers 60 of prepreg tapes 2 lying one above the other. As shown schematically in FIG. 16, the prepreg strips 2 extend parallel within a respective layer 60 to each other. In adjacent layers 60 the extend

Prepreg tapes 2 in different directions, e.g. across from each other. 16 shows only two layers or layers 60 for the sake of simplicity. The individual layers 60 are relative to one another on individual, preferably discrete, e.g. periodically repeating places or stitched at points or

otherwise connected, e.g. welded, forfeited, entangled or linked. For reasons of clarity, this is shown in FIG. 16 only at a single point. As shown by way of example, a connecting strand 3 can be used to connect the individual layers 60. Here, the connecting strand 3 wraps around, for example, two intersecting prepreg bands 2 at an intersection. The connecting strand 3 is preferably designed as a thread 34.

In the semifinished product 1 shown by way of example in FIG. 16, the prepreg strips 2 can slide within one layer 60 and the layers 60 against one another, as a result of which the

The risk of wrinkles when forming the semi-finished product 1 is reduced.

In the following, using FIGS. 6 to 15 an example of a method for

Production of a curved structural component B explained, e.g. of a structural component B, as is shown by way of example in FIG. 17.

17 shows an example of a curved structural component B in the form of a

Pressure cap for an aircraft (not shown). The structural component B can in particular have a circular peripheral edge E. As shown in FIG. 17, the structural component can, for example, be dome-shaped or dome-shaped and thus curved in several directions of curvature. 17 is a

The apex P of the arched shape of the structural component B is shown, which is given by an intersection of lines of symmetry S1, S2 of the structural component B.

To produce the structural component B, a layer structure 100 is first formed, which has a plurality of layers 110 lying one above the other, the layers 110 each containing at least one semifinished product 1, as is exemplified by FIGS. 1, 2 and 16.

The layers 1 10 realized as flat mats. The figures 6 to 8 show an example of the production of a single layer 1 10 from several of the semi-finished products 1 shown in FIG thermoplastic or cohesively connected, e.g. by ultrasonic welding. The second

End sections 32 of the connecting strands 3 of the further semifinished product 12 are also thermoplastic bonded to prepreg strips 2 of the first semifinished product 1 1, for example also by ultrasonic welding. As shown in FIG. 6, the first end sections 31 of the connecting strands 3 of the first semifinished product 1 1 overlap the outermost second prepreg band 2B of the second semifinished product 12 and the second end sections 32 of the connecting strands 3 of the first

Semi-finished products 12 overlap the outermost first prepreg tape 2A of the first

Semi-finished products 1 1.

The semifinished product 1 shown in FIG. 2 can be connected in the same way to other such semifinished products 1.

FIG. 7 shows a layer 110, which was formed by several semi-finished products 1 as described above. Here, the individual semi-finished products 1 before connecting them to a layer 1 10 each at opposite ends 1A, 1 B. As a result, different circumferential shapes of the layers 110 can be generated, for example an approximately circular circumference, as is shown by way of example in FIG. Optionally, a further cut can be made by the

Semi-finished 1 layer 1 10 are made to the exact desired

Set the circumferential shape of the layer 1 10, e.g. circular, as shown in Fig. 8.

Of course, it is also conceivable to form a layer 110 from a semi-finished product 1 in each case.

When using semifinished products 1, which are designed as multiaxial fabrics, as is shown by way of example in FIG. 16, one layer contains 1 10 of the

Layer structure 100 a plurality of layers 60 of the semi-finished product 1.

The layer structure 100 is generally formed by stacking or depositing a plurality of layers 110 one on top of the other, as exemplified in FIG. 9 in one

Exploded view is shown. As shown schematically in FIG. 9, the layer structure 100 can in particular be designed such that the

Extend prepreg tapes 2 in different layers 1 10 in different directions R1 10. In particular, it can be provided that the prepreg strips 2 extend from mutually adjacent layers 110 of the layer structure 100 in intersecting directions R1 10. As shown by way of example in FIG. 1 1, the layer structure 100

for example, by sequentially stacking the layers 1 10 on a flat

Storage area 150a are formed. As an alternative to this, the layer structure 100 can also be formed by stacking the layers 110 on a curved storage surface 150a are as shown schematically in Fig. 12. In the latter case, due to the slack nature of the textile fabric 4 or the multiaxial scrim 6, there is at least partial deformation of the individual layers 110 in accordance with the curved storage surface 150a. The arched

Storage surface 150a can be provided, for example, by a contour surface 210a of a molding tool 200 which corresponds to the curved shape of structural component B. The molding tool 200 is explained in detail below. After the layer structure 100 has been formed, the layers 110 are optionally thermoplastic bonded, for example in the region of the vertex P of the arched shape to be produced, at a connection point 120, e.g. by ultrasonic welding. In general, the connection point is selected such that no or only a very slight displacement of the layers 110 relative to one another is necessary in the corresponding region during the subsequent deformation. If the layers 110 have been deposited on a curved storage surface 150a, there is optionally also a thermoplastic connection at further connection points 121 away from the apex P, e.g. also by

Ultrasonic welding. 10 is a schematic plan view of a

Layer structure 100 shown, which is formed from layers 1 10 with a circular circumference. The connection point 120 is formed with respect to a radial direction in the area of the center. This is the area that the

Forms apex P of the structural component B shown by way of example in FIG. 17.

In a further step, the layer structure 100 is deformed into the curved shape. This forming step takes place at a forming temperature which is lower than a melting point of the thermoplastic materials 20, 30 des Semifinished product 1. The forming temperature is thus less than a melting point of the matrix material 20 of the prepreg strips 2 and less than a melting point of the thermoplastic material 30 of the connecting strands 3. As a result, the prepreg strips 2 and the reinforcing strands 3 of the semifinished products 1 contained in the layers 110 are in one solid state, which reduces the friction or the viscous adhesion between and within the layers 1 10. In addition, during the forming process, the reinforcing fibers within the individual prepreg bands are still supported by solid matrix material, so that the fibers are better protected from dents even in the event of a pressure load in the longitudinal direction of the fibers due to the forming process. This prevents the formation of wrinkles, waviness or undulations in the fiber layers.

Forming can take place, for example, in a cavity 205 of a molding tool 200, as is shown schematically in FIG. 13. The molding tool 200 has a molded part 210 with a contour surface 210a corresponding to the curved shape of the structural component B and an abutment part 220. The

The contact part 220 and the molded part 210 can be positioned relative to one another in a closed position, as is shown by way of example in FIG. 13. In the closed position, a cavity 205 is formed between the contour surface 210a and an inner surface 220a of the contact part 220. Optionally, a seal 215 can be arranged between the contact part 220 and the molded part 210, which seals the cavity 205 hermetically in the closed position of the molding tool 200. As shown by way of example in FIG. 13, the molded part 210 can be designed as a flatly extending first molded sheet 21 1 and the contact part 220 as a flatly extending second molded sheet 221. The inner surface 220a of the plant part 220 can correspond to the shape of the Structural component B or complementary to the contour surface 210a of the molded part 210.

For reshaping the one formed on the flat storage surface 150a

Layer structure 100 (FIG. 11) or for further shaping of the already partially deformed layer structure 100, which was produced on the curved storage surface 150a (FIG. 12), the shaped part 210 and the abutment part 220 are subjected to a force F such that the Layer structure 100 is pressed between molded part 210 and plant part 220.

The force F can be generated, for example, by creating a vacuum in the cavity 205 of the molding tool 200 by means of a fluidically conductive to the cavity 205

coupled evacuation device or pump 230 can be applied, as shown in FIG. 13 as an example. At the same time, this ensures that 100 air pockets possibly present in the layer structure are removed or reduced. As an alternative or in addition to this, the force F can also be generated by generating a magnetic field which is coupled into a magnetizable material assigned to the first shaped plate 21 1 and / or into a magnetizable material assigned to the second shaped plate 221 in such a way that the layer structure is formed by the compression pressure is applied to the mold plates. For example, it can be provided that the first and / or the second shaped plate 21 1, 221 and / or a substructure, such as the mold half 310, is formed from a magnetizable metal material and a magnetic field is generated which the first and the second shaped plate 21 1, 221 contracts or compresses relative to each other. This is shown by way of example in FIG. 15. Accordingly, the magnetizable material is assigned to the shaped sheets 21 1, 221 in that they are themselves formed from or contain a magnetizable material. The first mold plates 21 1 can be magnetized Material can also be assigned in that the mold half 310 is formed from or has a magnetizable material. To generate the magnetic field, a magnetic device 240 can be provided with a plurality of electrical induction coils 241, which are distributed along the contour surface 210 a of the molded part 210. Instead of electrical induction coils 241, permanent magnets (not shown) can also be provided. In general, the magnetic device 240 can be set up to generate a magnetic field

Have magnetic field generators. The following is an example

Induction coils 241 are referred to as magnetic field generators, the features disclosed for this also apply in an analogous manner to other magnetic field generators. 15, the magnet device 240 can be located in the substructure of the mold half 310 or, for example, on the other side, above the upper mold plate 221. In particular in the latter case, the magnet device 240 can be at least partially flexible or articulated have designed support structure which is coupled to the second shaped plate 221, so that the induction elements 241 are flexibly connected to one another and can adapt to the shaped plate 221 in order to transmit the pressure as uniformly as possible. The magnet device 240 is in particular set up to generate a magnetic field directed transversely to the contour surface 210a.

13 also shows the result of a further optional method step, in which reinforcement profiles 130 were placed on a layer 110 of the layer structure 100 lying opposite the contour surface 210a. The reinforcement profiles 130 can, for example, have a double-T-shaped cross section, as is shown schematically in FIG. 13, and also have a thermoplastic material. For example, the reinforcement profiles 130 can be formed from a fiber-reinforced thermoplastic material be. The molding tool 200 is then brought into the closed position, as shown in FIG. 13. In this case, the contact part 220 or the second shaped plate 221 is provided with recesses 223 through which a web of the reinforcing profile 223 extends. For this purpose, the second shaped plate 221 can be formed, for example, in two parts, a first part having the recesses 223 in the form of slots which are open on one side and are closed by a second part. Alternatively, the stiffening profiles 130 can also be inserted into enveloping bulges or depressions (not shown) of the second shaped plate 221 or of the contact part 220. This improves the tightness of the cavity 205. The stiffening profile 130 can generally be pressed against the layer structure 100 in the cavity 205 by means of the contact part 220.

In a further step, the formed layer structure 100 is heated to a temperature which is greater than the melting point of the thermoplastic materials 20, 30 of the semifinished product 1. As a result, the thermoplastic matrix material 20 of the prepreg strips 2 and the thermoplastic material 30 of the connecting strands 3 are melted, as a result of which the individual layers 110 of the layer structure 100 fuse with one another and are thereby connected. The optional stiffening profiles 130 are thereby also fused to the uppermost layer 110.

The heating is preferably carried out in the cavity 205 of the molding tool 200.

Optionally, a vacuum is also created in the cavity 205 by means of the pump 205. A heater 250 can be used to heat the cavity 205

be provided. 13, heater 250 is exemplified as one

Induction heater 252 executed which one or more

Induction coils 253 has in at least one of the shaped plates 21 1, 221 to induce an alternating magnetic field, which inductively heats the shaped plate 21 1, 221, so that the cavity 205 is heated. 13 is the

Heating device 250 located on the side of molded part 210, for example. In the example in FIG. 13, the first shaped sheet 21 1 is preferably excited thereby, so that the layer structure 100 heats up from this and the optional ones

Stiffening profiles 130 are primarily heated in the area in which they rest on the layer structure 100.

15, the heating device 250 is exemplified as an infrared radiator 251

executed, which is arranged on the part of the system part 220. A further infrared radiator (not shown) can optionally be arranged on the part of the molded part 210. In general, the infrared radiator 251 is used to generate

Heat radiation is set up to heat the cavity 205. Of course, an induction heating device 252 can also be provided in FIG. 15, as was explained with reference to FIG. 13. It is also conceivable that the

Magnetic device 240, which is provided per se for applying the compression pressure, is also used as a heating device. For this purpose, it can be provided that a direct current flows through the induction coils 241 to generate the direct magnetic field for applying the compression pressure and an alternating current flows through the cavity 205 for heating.

Optionally and independently of the design of the heating device 250 or the supply of heat for heating, the molding tool 200 can be placed on a mold half 310 during the heating, as is shown by way of example in FIG. 15. The mold half 310 can have a mold surface 310a, which

corresponding to a rear surface 210b of the molded part 210 of the

Molding tool 200 may be shaped. Here, an insulation layer 31 1 between the mold surface 310a of the mold half 310 and the rear surface is advantageous 210b of the molded part 210 arranged to largely avoid heating the mold half 310. This has the advantage that the mold half 310 is exposed to smaller temperature fluctuations and is consequently less deformed by thermal expansion. The mold half 310 serves in particular as a support for the molding tool 200. The molding plates 21 1, 221 can thus be made relatively thin. This speeds up the heating of the cavity 205 and reduces the tool costs. As is further shown in FIG. 15, the magnet device 240 can be integrated into the mold half 310, for example. In a further process step, a

Compression pressure is a consolidation of the layer structure 100 by cooling to a solidification temperature that is less than the melting point of the

thermoplastic materials 20, 30 of the semi-finished product 1. When consolidating, the layer structure 100 cools down or heat is removed from the

Layer structure. As a result, the thermoplastic material 20, 30 solidifies and the structural component B is formed.

The consolidation can also take place in the cavity 205 of the molding tool 200. For cooling, the heating device 250 is switched off and / or the molding tool 205 and the heating device 250 are spatially separated from one another. As shown by way of example in FIG. 15, the consolidation or

Cooling also take place on the mold half 310. The compression pressure can be generated by the vacuum device 205 and / or by the magnet device 240. In general, compression pressure 200 can be applied by molding tool 200.

Alternatively, the molding tool 200 for consolidation or cooling can be formed in one by two mold halves 310, 320 of a pressing tool 300 Cavity 305 arranged and the compression pressure can be applied through the mold halves 310, 320, as shown schematically in Fig. 14. The pressing tool 300 shown by way of example in FIG. 14 has a first mold half 310 and a second mold half 320. The first mold half 310 can be designed analogously to the mold half described with reference to FIG. 15 with a first mold surface 310a. The second molding surface 320 has a second molding surface 320a which is designed to correspond to an outer surface 220b of the contact part 220. The mold halves 310, 320 can be moved relative to one another between an open position and a closed position by means of a movement device 330, for example in the form of a hydraulic drive. Fig. 14 shows that

Press tool 300 in a closed position or position in which the second mold surface 320a faces the first mold surface 310a and the

Mold halves 310, 320 or the mold surfaces 310a, 320a of the mold halves 310, 320 define the cavity 305.

As schematically indicated in FIG. 14 by the arrows A1, A2, the mold halves 310, 320 press the molded part 210 and the contact part 220 and thus the layer structure 100, which is located in the cavity 205 of the molding tool 200, together. The compression pressure is thus applied by the pressing tool 300. During consolidation or cooling, the

Cavity 305 of the pressing tool 300 and / or the cavity 205 of the molding tool 200 can be evacuated. If the layer structure 100 together with the

Heated mold plates 21 1 and 221 outside of the pressing tool, the cavity 205 of the forming tool 200 can optionally be evacuated before being inserted into the cavity 305 of the pressing tool 300, which facilitates the holding together of the layer structure 100 and the form plates 21 1, 221 and in the layer structure 100 beforehand air is removed before melting. The mold halves 310, 320 have when consolidating or cooling the

Layer structure 100 has a temperature that is lower than the melting temperature of the thermoplastic materials 20, 30. As a result, the mold halves 310, 320 form heat sinks, which accelerates the cooling of the cavity 205. The cooling can be further accelerated in that the mold halves 310, 320 from one

Metal material with high thermal conductivity, e.g. Aluminum or the like are formed. The heat capacity of the mold halves 310, 320 is advantageously a multiple, e.g. ten times the heat capacity of the mold plates 21 1, 212 of the mold 200.

Although the present invention has been explained by way of example using exemplary embodiments, it is not restricted to these but can be modified in a variety of ways. In particular, combinations of the above exemplary embodiments are also conceivable.

REFERENCE LIST

1 semi-finished product

1 A, 1 B ends of the semi-finished product

2 prepreg tapes

2A first prepreg tape

2B second prepreg tape

3 connecting strands

4 fabrics

5A, 5B connecting lines

6 multi-axial scrims

1 1 first semi-finished product

12 second semi-finished product

20 thermoplastic matrix material

21 reinforcing fibers

30 thermoplastic material

31 first end section of the connecting strands

32 second end section of the connecting strands

33 foil tape

34 thread

35 filaments

41 first end region of the fabric

42 second end region of the fabric 60 layers

100 layers

1 10 location

120 connection point

130 reinforcement profiles 150a storage space

200 mold

205 mold cavity 210 molded part

21 1 first shaped sheet

210a contour surface of the molded part 210b rear surface of the molded part 215 seal

220 system part

220a inner surface of the plant part

221 second shaped sheet

230 pump

240 magnetic device

250 heating device

251 infrared heater

252 induction heater

300 pressing tool

305 cavity of the pressing tool 310 first mold half

310a mold surface of the first mold half

320 second mold half

320a mold surface of the second mold half 330 movement device

B structural component

b2 Width of the prepreg tapes

E peripheral edge of the structural component F force

I2 Length of the prepreg tapes P vertex

R1 first direction

R2 second direction

S1, S2 lines of symmetry R1 10 direction

Claims

CLAIMS 1. Semi-finished product (1) for the production of a structural component (B), with:

a plurality of prepreg tapes (2) which extend along one another and each have unidirectionally arranged reinforcing fibers (21) embedded in a thermoplastic matrix material (20); and a variety of a thermoplastic material (30)

containing connecting strands (3);

wherein the connecting strands (3) and the prepreg strips (2) are connected to form a textile fabric (4) in which each of the

Connecting strands (3) crosses several of the prepreg bands (2); and wherein the connecting strands (3) and the prepreg strips (2) in a first end region (41) of the flat structure (4) and an opposite second end region (42) of the flat structure (4) each along a connecting line (5A; 5B) are cohesively connected. 2. Semi-finished product (1) according to claim 1, wherein the prepreg tapes (2) extend in a first direction (R1) and the connecting strands (3) extend in a second direction (R2) running transverse to the first direction (R1) , and wherein an outermost first prepreg tape (2A) with respect to the second direction (R2) and an outermost second prepreg tape (2B), which is opposite to the first prepreg tape, for

Formation of the connecting lines (5A; 5B) are each integrally connected to the connecting strands (3).

3. Semi-finished product (1) according to claim 1 or 2, wherein the prepreg strips (2) and the connecting strands (3) are interwoven or intertwined.

4. Semi-finished product (1) according to one of the preceding claims, wherein the

Connecting strands (3) each have a first end section (31) and a second end section (32) lying opposite to this, the first and second end sections (31; 32) each projecting beyond the connecting lines (5A; 5B). 5. Semi-finished product (1) for producing a structural component (B), with:

a plurality of prepreg bands (2), each in one

thermoplastic matrix material (20) have embedded, unidirectionally arranged reinforcing fibers (21);

wherein the prepreg tapes (2) are arranged to form a multiaxial fabric (6) which has a plurality of layers (60) lying one above the other

Comprises prepreg bands (2);

the prepreg strips (2) running parallel to one another within a layer (60); and

the layers (60) relative to one another at individual locations, preferably at discrete, in a periodically repeating pattern

arranged points are connected, in particular sewn, forged, interwoven, welded or otherwise connected, preferably by means of a plurality of a thermoplastic material (30)

containing connecting strands (3).

6. semi-finished product (1) according to any one of the preceding claims, wherein the

Connecting strands (3) are formed as film strips (33) or threads (34) consisting of the thermoplastic material (30).

7. A method of manufacturing an arched shape

Structural component (B), comprising the following process steps:

Forming a layer structure (100) from a plurality of layers (1 10), the layers (1 10) each having at least one semi-finished product (1) according to one of the

have the preceding claims;

Forming the layer structure (100) into the curved shape at a

Forming temperature, which is less than a melting point of the thermoplastic materials (20; 30) of the semi-finished product (1);

Heating the formed layer structure (100) to a temperature which is greater than the melting point of the thermoplastic materials (20; 30) of the semi-finished product (1); and

applying a compression pressure cooling the layer structure (100) to a solidification temperature which is lower than the melting point of the thermoplastic materials (20; 30) of the semi-finished product (1).

8. The method according to claim 7, wherein the individual layers (1 10) of

Layer structure each formed from a plurality of semi-finished products (1) according to claim 4, in that at least the first end sections (31) of the connecting strands (3) of a first semi-finished product (11) are thermoplastic bonded to prepreg bands (2) of a respective further semi-finished product (12), preferably also the second end sections (32) of the

Connecting strands (3) of the further semifinished product (12) with prepreg bands (2) of the first semifinished product (1 1) are thermoplastic.

9. The method according to claim 7 or 8, wherein the layer structure (100) is formed such that the prepreg tapes (2) extend in different layers (1 10) in different directions (R1 10).

10. The method according to any one of claims 7 to 9, wherein the layer structure is formed by sequential stacking of the layers (1 10) on a flat storage surface (150a) and forming in a cavity (205)

Molding tool (200) takes place, the cavity (205) through a molded part

(210) with a curved shape of the structural component (B)

corresponding contour surface (210a) and a flat contact part (220) is formed. 1 1. The method according to any one of claims 7 to 9, wherein the layer structure

by sequentially stacking the layers (1 10) on an arched

Storage surface (150a) is formed and thereby simultaneously formed into the curved shape, the storage surface (150a) being formed a contour surface (210a) of a molded part (220) of a molding tool (200) corresponding to the curved shape of the structural component (B), being the

Mold tool (200) additionally has a flat contact part (220) for forming a cavity (205) with the molded part (210).

12. The method according to claim 10 or 1 1, wherein the heating of the layer structure (100) in the cavity (205) of the mold (200).

13. The method according to any one of claims 10 to 12, wherein the molded part (210) of the molding tool (200) as a flatly extending first molded sheet

(21 1) is formed, and wherein the contact part (220) is designed as a flat extending second shaped plate (221).

14. The method according to claim 13, wherein for applying the

Compression pressure using a magnetic device (240) a magnetic field is generated, which is thus placed in the first shaped plate (21 1)

assigned magnetizable material and / or is coupled into a magnetizable material assigned to the second shaped plate (221) in such a way that the layer structure is subjected to the compression pressure through the shaped plates, the first and / or the second shaped plate (21 1;

221) are preferably made of a magnetizable metal material.

15. The method according to any one of claims 10 to 14, wherein the mold (200) for heating and cooling is placed on a mold half (310), and wherein the compression pressure is applied during cooling by the mold (200).

16. The method according to any one of claims 10 to 13, wherein the mold (200) for cooling in one by two mold halves (310; 320) one

Press tool (300) formed cavity (305) and the

Compression pressure is applied through the mold halves (310; 320).

17. The method according to any one of claims 13 to 16, wherein the heating of the

Layer structure (100) by inductive heating of the shaped plates (21 1; 221) or by means of infrared radiation.

18. The method according to any one of claims 10 to 17, wherein a vacuum is generated in the cavity (205) of the mold (200).