Method for manufacturing a carrier component, carrier component and carrier having the carrier component

Abstract

A method for manufacturing a carrier component from fiber-reinforced plastic comprises the following steps: providing a surface region with an inner side, an outer side and a receiving section arranged at the inner side, the surface region consisting of a fiber-reinforced thermoplastic material; providing a reinforcement component with a connection surface, the reinforcement component consisting of a fiber-reinforced thermoplastic material; contacting the reinforcement component and the surface region so that the connection surface is located on the receiving section; areally heating a joining region in which the connection surface and the receiving section of the reinforcement component are located so that the reinforcement component and the surface region are welded to each other; cooling the joining region; comparing the obtained geometry of the combination formed by the reinforcement component and the surface region with a predeterminable geometry; if the obtained geometry deviates from the predeterminable geometry, reheating the joining region, deforming the reinforcement component and the surface region and cooling. A carrier component and a carrier having the carrier component are also provided.

Description

Technical Field

[0001] The invention relates to a method for producing a carrier component from fiber-reinforced plastic, and to a carrier component or a carrier having such a carrier component. Background Art

[0002] Larger vehicles and especially transport aircraft are increasingly manufactured with the aid of components made of fiber-reinforced plastic. Components, especially in the case of transport aircraft, are often of large size in order to reduce the effort of connecting a plurality of components. However, when using large-sized components made of fiber-reinforced plastic, shape deviations or surfaces that need to be trimmed may sometimes occur. If, for example, the surface area is equipped with a reinforcement component, the preform of the surface area and the preform of the reinforcement component are sometimes placed together on the forming mold in order to then be heated together in an autoclave for hardening. Due to different layer thicknesses, cooling at different speeds may occur after heating. For example, the reinforcement component in the connection area has not yet completely cooled, while the adjacent surface area without the reinforcement component has completely cooled. As a result, different expansions may occur, which are reflected as certain ripples on the outer surface.

[0003] Furthermore, with fiber-reinforced plastics it can happen that the fibers embedded in the matrix are partially stacked or not oriented completely straight, which results in relatively fine but visible ripples.

[0004] In particular, the connection methods used for fiber-reinforced plastics in the aviation industry are often based on the use of rivets. Sometimes it cannot be ruled out that such riveted connections result in visible rivets on the outer surface of the manufactured component.

[0005] These three types of shape deviations can be eliminated by different measures. What they have in common is that a thin material layer is additionally applied at least in places in order to subsequently process the entire surface of the component by removing material. This can be laborious and also increases the weight of the manufactured component. If the component is a part of an aircraft, this should be avoided as much as possible. Summary of the invention

[0006] It would be desirable to have a method for producing large-format components, in particular from fiber-reinforced plastics, which method does not lead to the aforementioned shape deviations.

[0007] It is therefore an object of the present invention to specify a method for producing a component from fiber-reinforced plastic in which particularly advantageous component and surface qualities can be produced without additional application of material.

[0008] This object is achieved by a method for producing a carrier component from fiber-reinforced plastic. Advantageous developments and embodiments can be inferred from the exemplary embodiments and the following description.

[0009] A method for producing a carrier component from fiber-reinforced plastic is provided. The method comprises the following steps: providing at least one surface region with an inner side, an outer side and a receiving section arranged at the inner side, wherein the surface region consists of a fiber-reinforced thermoplastic material; providing at least one reinforcement component with a connection surface, wherein the reinforcement component consists of a fiber-reinforced thermoplastic material; contacting the at least one reinforcement component and the at least one surface region so that the connection surface is located on the receiving section; areally heating a joining region in which the connection surface of the reinforcement component and the receiving section are located so that the at least one reinforcement component and the at least one surface region are welded to one another; cooling the joining region; comparing the obtained geometry of the combination formed by the reinforcement component and the surface region with a predeterminable geometry; and if the obtained geometry deviates from the predeterminable geometry, reheating the joining region, deforming the reinforcement component and the surface region and cooling them in order to achieve the predeterminable geometry.

[0010] In principle, the method differs from known methods in that, instead of a fiber-reinforced thermosetting plastic-based material, a thermoplastic material with reinforcing fibers is used. Suitable thermoplastic materials for realizing the matrix may include PPS (polyphenylene sulfide), PEEK (polyetheretherketone), PEKK (polyetherketoneketone) or others.

[0011] In addition, the reinforcing fibers can also be selected according to the purpose of use and, for example, contain carbon fibers, glass fibers, aramid fibers, Kevlar fibers, etc. The use of such materials leads to special advantages in the correctability of possible shape deviations. For thermosetting plastic materials, the reinforcing fibers can be embedded in liquid or pasty parts, which are made of resin systems. After the resin hardens, it is no longer possible to perform shape corrections there. The hardening process is irreversible and certain precautions must be taken: when the resin hardens, the desired shape is achieved or maintained.

[0012] However, the use of thermoplastic materials for embedding the reinforcing fibers makes it possible to make subsequent corrections to the geometry. If, in the example mentioned at the outset, an inner reinforcement component with a surface region is implemented, theoretically certain shape deviations can occur during hardening even when using thermoplastic fiber-reinforced plastics. However, such shape deviations are eliminated according to the invention by the fact that, after the deviation from the theoretical geometry is detected, local heating can be performed again in order to mechanically change the composite formed by the reinforcement component and the surface region to the desired theoretical geometry. The hardening process is completely reversible in thermoplastic materials.

[0013] However, the method presented also has the particular advantage that a riveted connection can be practically completely dispensed with. Due to the reversible hardening of the material, it is also possible to melt the material locally, so that the melted regions of the two components to be connected to each other penetrate each other, thereby achieving a practically integral component. Thus, it is not necessary to produce a riveted connection by drilling, deburring, cleaning, sealing, inserting and deforming the riveted body in order to produce the connection. Local heating is sufficient, by which the two relevant joining partners (especially under the action of an additional pressing force) can achieve a material-fitting connection.

[0014] By locally heating the connection area between the components to be connected in a planar manner, the entire heating of the composite formed by the surface area and the reinforcing component can also be limited to a very small area, that is to say a relatively small volume, so that the expansion effect itself is significantly smaller due to the temperature gradient in the component.

[0015] The heating should be limited to very thin layers in order to fully exploit this advantage. The connection region can be heated by inductive methods, using heating resistors or by conduction, wherein it is preferred to integrate the heating layer into one of the components to be connected to one another.

[0016] The method according to the invention can therefore limit or eliminate the use of riveting. Uneven surfaces caused by protruding rivet heads and the like can be avoided. At the same time, heat-induced ripples in the manufactured component can be significantly reduced and, moreover, eliminated significantly more simply. It is therefore not necessary to apply additional material to the outer surface of the manufactured component.

[0017] In this connection, it should be pointed out that the receiving section on the inner side of the surface region does not have to have a special design. Instead, the receiving section can be a defined surface area in which the connecting surface of the at least one reinforcement component is placed. Furthermore, in the simplest case, the connecting surface of the at least one reinforcement component is only a surface whose course corresponds to the receiving section. The connecting surface serves only to establish a flush surface contact between the at least one reinforcement component and the at least one surface region in order to subsequently bring about welding by local heating.

[0018] In a favorable embodiment, it is proposed that at least one surface area has reinforcing fibers spread out in parallel and the reinforcing fibers are embedded in a thermoplastic matrix material. This should be understood in this way, that is, the fiber bundle can be processed into a flat layer assembly with reinforcing fibers parallel to each other by mechanical combing or similar processes for this purpose. By combing the reinforcing fibers, the reinforcing fibers can be embedded in the matrix material in particular at a predetermined spacing and with an accurately adjusted orientation and a predetermined layer thickness. For example, in a thermoplastic resin, such a flat layer assembly with parallel fibers can be provided as a thin, narrow nonwoven tape or fabric layer. They can be placed adjacent to a larger surface area on a corresponding forming mold with a desired fiber direction and are interconnected. The overlapping of different amounts of reinforcing fibers can thus be suppressed, which can eliminate the fine ripples of the manufactured component.

[0019] In an advantageous embodiment of the present invention, a step of placing a conductive layer on the connection surface and / or the receiving section is also performed, wherein the planar heating includes applying a voltage to the conductive layer. The conductive layer is particularly used as a resistance heating layer. The conductive layer can be implemented as a film or a fabric. The material of this layer should have sufficient conductivity and can be made of a metal material and / or contain a high proportion of carbon. It is meaningful to define such connecting wires, connection points, etc., that is, they are connected to the conductive layer and extend from the connection area, so that the conductive layer can be contacted with an external power source. For this purpose, the layer is arranged to trigger a current to flow through the layer by applying a voltage, and the current causes the layer to heat due to the resistance of the layer. It is thus possible to heat only the connection surface and the receiving section in a targeted manner. The layer should be implemented as thin as possible here, so that it is retained in the manufactured component later and only causes a negligible weight increase. However, the layer should also be designed in such a size that sufficient heating power can be achieved. In general, in this embodiment it may be necessary to ensure that when the conductive layer is heated the voltage and / or the current intensity occurring is monitored or limited, so that damage to the conductive layer can be prevented.

[0020] The conductive layer is produced from a carbon-containing material in the form of a mesh formed by linear elements. Carbon fibers or carbon nanotubes, for example, can be used for this purpose. With the linear elements, square, rectangular or other regularly shaped meshes can be formed. In this way, the heating of the connection area can be carried out in the form of a mesh. In this way, the entire connection area is heated depending on the size of the mesh. It is not necessary to fill the enclosed surface with material that is used only for heating purposes.

[0021] In a particularly advantageous embodiment, the conductive layer consists of a mesh of carbon nanotubes, which have a particularly high tensile strength and sufficient electrical conductivity for heating purposes. The integration of such a mesh results in a significant weight advantage, since the additional weight introduced by the carbon nanotubes is practically immeasurable.

[0022] Heating can also be carried out by locally introducing ultrasound. In such a method, also known as ultrasonic welding, heat is generated by converting ultrasonic vibrations into mechanical vibrations. The vibrations are introduced to one or both joining partners via an interface in the form of a sonotrode. This leads to interface and molecular friction, which leads to local heating. In the present case, it is meaningful to apply sound waves to the at least one reinforcement component. In particular, very short sound pulses timed in a certain pattern can achieve local, concentrated heating in the connection area.

[0023] In a particularly preferred embodiment, cooling includes the step of maintaining moderate heating of the connection area during cooling. Therefore, the cooling of the connection area (where the components are welded together) is affected by maintaining heat input. This can be achieved in the following way, that is, the conductive layer is connected to a control unit, which is connected to a power supply. The control unit can, for example, apply a certain voltage to the conductive layer or set a certain current intensity in order to perform sufficient heating for welding. In particular, the maximum heating power is achieved under the condition of maximum current intensity. For cooling purposes, the heating power can be reduced at least at a certain moment and at least for a certain duration. The heating power is preferably reduced in such a way that the heat loss from the connection area to the outside exceeds the heating power still delivered at that time. This means that the heat loss is significantly delayed relative to simply separating the conductive layer. This leads to a more gentle cooling of the connection area, whereby possible thermal stresses and expansion effects can be further reduced. It is conceivable that the control unit is set up to perform multiple heating power reductions during cooling. The number of reasonable such steps and their respective durations depend on the type and characteristics of the joining partner. Preferably, such a control unit may be set up to determine the number of heating power reduction steps and their duration based on a cooling curve determined theoretically or experimentally.

[0024] In another advantageous embodiment, the placement of the conductive layer includes an integrated sensor wire, which can be connected to a control unit, wherein the control unit controls cooling in the following manner: based on the temperature determined by means of the sensor wire, by delivering thermal power by delivering electrical power to the conductive layer. The sensor wire can be provided by the same material as the conductive layer or with material properties similar to the conductive layer. Such a sensor wire can extend over a certain part of the conductive layer and can be electrically connected to the control unit from the outside. The sensor wire is configured to change its resistance depending on the temperature. The control unit can determine the temperature in the connection area based on the measured resistance. Based on the temperature determined in the connection area, the heating power can be adjusted to perform guided cooling. It is thus possible to basically abandon the determination of the cooling curve based on experiments or theory, and to directly perform cooling based on the current temperature in the connection area.

[0025] The additional step of heating and deforming can, for example, include placing a forming tool on the inside of the surface area and applying a deforming force outwards, i.e. in the direction of the outside of the surface area. The forming tool can, for example, be matched to the at least one reinforcement component and allow slight shape corrections after repeated heating.

[0026] However, the repeated heating can be extended over a larger area than just the connecting area. Thermal stresses can thus also be reduced in adjacent areas, thereby achieving a predefined geometry. The repeated heating can be achieved in particular by a heating device, which is arranged at the forming mold.

[0027] The invention furthermore relates to a carrier component having at least one surface region and at least one reinforcement component arranged on the inner side of the surface region, wherein the carrier component is produced by means of the above-mentioned method.

[0028] The invention further relates to a vehicle having at least one such vehicle component. The vehicle can be, in particular, an aircraft and preferably a transport aircraft.

[0029] Furthermore, the invention can relate to a system which is designed for manufacturing a carrier component from fiber-reinforced plastic. The system can have a control unit, a forming mold, a heating device and a measuring device. The control unit can also be connected to the heating device. The control unit can be designed to control the heating device for heating the connection area between the above-mentioned surface component and the at least one reinforcement component and to detect by means of the measuring device whether the geometry determined by the measuring device after cooling deviates from a predeterminable geometry. If there is a deviation, the control unit can control the forming mold and the heating device in such a way that repeated heating takes place and the forming mold performs a deformation. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Further features, advantages and application possibilities of the present invention are apparent from the following description of the exemplary embodiments and the accompanying drawings. All described and / or illustrated features constitute the subject matter of the present invention by themselves and in any combination, independently of their combination in the individual exemplary embodiments. In addition, the same reference numerals in the drawings represent the same or similar objects.

[0031] Figure 1 A partial cross section of a carrier component to be manufactured is shown.

[0032] Figure 2 A detail of a reinforcement component and a conductive layer arranged thereon for heating the connection region is shown.

[0033] Figure 3 Shown is the spreading of the reinforcement fibers when manufacturing the skin region.

[0034] Figure 4 A detail view showing the connection area of ​​the reinforcement element.

[0035] Figure 5 Shows the Figure 1 Partial cross section and the Figure 4 reinforcement components.

[0036] Figure 6 A block diagram based illustration of the method according to the invention is shown.

[0037] Figure 7 An aircraft is shown which has one or more vehicle components produced using the method according to the invention. DETAILED DESCRIPTION

[0038] Figure 1 The schematic diagram shows a skin region 2 and a reinforcement component 4. The skin region 2 has an outer side 6, an inner side 8 and a receiving section 10 arranged on the inner side. The reinforcement component 4 is designed as a longitudinal reinforcement element (stringer) for the skin of an aircraft. The reinforcement component 4 has two legs 12, which provide a segmented connecting surface 14. The connecting surface 14 is in surface contact with the receiving section 10 on the inner side 8 of the skin region 2.

[0039] Both the surface region 2 and the reinforcement component 4 are produced from a fiber-reinforced thermoplastic. The thermoplastic can be, for example, PEEK or PEKK with embedded carbon fibers as reinforcing fibers.

[0040] The reinforcing fibers are only briefly shown in this illustration. By heating the connection region between the reinforcement component 4 and the surface region 2, which contains the receiving section 10 and the connection surface 14, the two components 2 and 4 can be welded to one another. As a result, the thermoplastic matrix material is partially melted, so that a mixing of the materials of the two components 2 and 4 is achieved locally in the joining region. After cooling, a virtually integral composite is thus present.

[0041] Local heating can be achieved in particular by arranging an electrically conductive layer 16. The electrically conductive layer is Figure 2 The conductive layer 16 is composed of a network of carbon nanotubes 18, which have a plurality of meshes 20. The conductive layer 16 is heated by connecting it to a power source 22, so that heating is performed only in the joining region.

[0042] The heating can be controlled by an optional control unit 21. The control unit 21 and the corresponding connecting lines are shown in dashed lines. In addition, a slight heating can be maintained when the connection area cools down, so that the cooling takes place more slowly. This can be achieved in particular by the control unit 21 by reducing the current supply.

[0043] Furthermore, a sensor line 23 can optionally be provided, by means of which the control unit 21 can monitor the temperature in the interior of the connection region. Based on this monitoring, a cooling control can be carried out.

[0044] A particularly favorable surface quality is achieved when the fibers of the components 2 and 4 are oriented parallel to one another and have no particular corrugation. Figure 3 , it is shown that the fiber bundle 24 for producing, in particular, the surface region 2 can be laid out by combing. This provides perfectly parallel and side-by-side oriented fibers 26 which can be incorporated into a thermoplastic matrix material 28. It is conceivable to produce a plurality of layers of a fiber-reinforced material made of thermoplastic and having combed fibers and to combine these layers in a web-like or strip-like manner.

[0045] Figure 4 A variant of a reinforcement component 30 is shown with a plurality of sections 32 or segments of the connecting surface, which are provided with the network of carbon nanotubes shown above. The reinforcement component 30 can also have cutouts 34, according to Figure 1 The reinforcing member 4 can extend through the cutout. The reinforcing member 30 may thus be part of a diaphragm, while the reinforcing member 4 is part of a longitudinal reinforcing element (stringer).

[0046] From Figure 4 The components in Figure 52 is shown in a combined form with a surface area 2, which can form part of a separator. The surface indicated by a black solid line can be interpreted as a connection area 36, ​​in which welding is performed.

[0047] exist Figure 6 The method according to the invention is schematically shown in a block diagram in FIG. The method comprises the steps of providing 38 at least one surface region 2 with an inner side 8, an outer side 6 and a receiving section 10 arranged at the inner side 8; providing 40 at least one reinforcement component with a connection surface 14; contacting 42 the at least one reinforcement component and the at least one surface region so that the connection surface is located on the receiving section; areally heating 44 a joining region in which the connection surface and the receiving section of the reinforcement component are located so that the at least one reinforcement component and the at least one surface region are welded to each other; cooling 46 the joining region; comparing 48 a determined geometry of the combination formed by the reinforcement component and the surface region with a predeterminable geometry; and if the determined geometry deviates from the predeterminable geometry, reheating 50 the joining region, deforming 52 the reinforcement component and the surface region and cooling 54 in order to achieve the predeterminable geometry. The method can further comprise placing 56 a conductive layer on the connection surface and / or the receiving section. During cooling 46 , moderate heating of the connection region can also be maintained 58 .

[0048] at last Figure 7 A traffic aircraft 60 is disclosed, which has at least one component 62 manufactured by the method according to the invention. This component is indicated only by dashed lines as an example. All other components can also be manufactured using the method according to the invention.

[0049] It should be supplemented that "having" does not exclude other elements or steps, and "one" or "an" does not exclude a plurality. It should also be noted that the features described with reference to one of the above embodiments can also be used in combination with other features of the other embodiments described above.

Claims

1. A method for producing a carrier component from fiber-reinforced plastic, the method comprising the following steps: - providing at least one surface region (2) having an inner side (8), an outer side (6) and a receiving section (10) arranged on the inner side (8), wherein the surface region (2) consists of a fiber-reinforced thermoplastic material, - providing at least one reinforcement component (4, 30) with a connection surface (14), wherein the reinforcement component (4, 30) consists of a fiber-reinforced thermoplastic material, - bringing the at least one reinforcing component (4, 30) and the at least one surface area (2) into contact, so that the connecting surface (14) is located on the receiving section (10) and a flush surface contact is established between the at least one reinforcing component (4, 30) and the at least one surface area (2), - areal heating of a joining zone in which the connection surface (14) of the reinforcing component (4, 30) and the receiving section (10) are located, so that the at least one reinforcing component (4, 30) and the at least one surface region (2) are welded to one another, - cooling the joining zone, - comparing the obtained geometry of the combination formed by the reinforcement element (4, 30) and the surface area (2) with a predeterminable geometry, and If the obtained geometry deviates from the predeterminable geometry, the joining zone is reheated, the reinforcing element (4, 30) and the surface region (2) are deformed and cooled in order to achieve the predeterminable geometry.

2. The method according to claim 1, The providing of the at least one surface region (2) comprises laying out reinforcing fibers (26) in parallel and embedding the reinforcing fibers (26) into a thermoplastic matrix material.

3. The method according to claim 1 or 2, Furthermore, the following steps are included: placing an electrically conductive layer (16) on the connection surface (14) and / or the receiving section (10), The areal heating comprises applying a voltage to the electrically conductive layer (16).

4. The method according to claim 3, The electrically conductive layer (16) is produced in the form of a mesh of linear elements from a carbon-containing material.

5. The method according to claim 3, The electrically conductive layer (16) consists of a network of carbon nanotubes.

6. The method according to claim 1 or 2, The areal heating and the reheating each comprise a local introduction of ultrasound.

7. The method according to claim 3, The cooling comprises the step of maintaining moderate heating of the joining zone during cooling.

8. The method according to claim 7, wherein the electrically conductive layer (16) comprises an integrated sensor line (23) which can be connected to a control unit (21), The control unit (21) controls the cooling by supplying thermal power by supplying electrical power to the electrically conductive layer (16) based on the temperature determined by means of the sensor line (23).

9. The method according to claim 1 or 2, The reheating and deforming steps include placing a forming die inside the surface area (2) and applying an outward deforming force.

10. A carrier component having at least one surface region (2) and at least one reinforcement component (4, 30) arranged on the inner side of the surface region (2), wherein the carrier component is produced using a method according to one of claims 1 to 9.

11. A carrier (60) having at least one carrier component according to claim 10.

12. The vehicle (60) according to claim 11, wherein the vehicle (60) is an aircraft (60).

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