METHOD FOR MANUFACTURING A REINFORCED COMPOSITE CORE, IN PARTICULAR FOR AIR VEHICLES, COMPOSITE CORE AND AIR VEHICLE

Description

[0001] The invention relates to a method for manufacturing a reinforced core composite component, particularly for aircraft. The invention further relates to a core composite component and an aircraft.

[0002] Core composites, by definition, consist of a core structure of relatively large height or thickness sandwiched between two thin outer layers. If areas within these composites are identified as being subject to increased stress, these areas are locally reinforced. This is achieved either by using core structures or components of higher density, or by incorporating materials such as fillers.

[0003] In open cell structures, a material with increased viscosity can be locally introduced according to the state of the art, completely filling the volume between the two cover layers. The material is introduced before the application of the cover layers or skins and cured together with them.

[0004] This method can be applied to the entire surface, but also to the area of ​​future cut edges. If the cut is made within the filled cells, the edge is simultaneously stabilized. This method is used, for example, for floor tiles in aircraft cabins to stabilize the edges against damage from wheel loads, such as those from food trolleys.

[0005] Especially in the production of aircraft floor panels, another well-known method for local reinforcement and subsequent component bonding is used. Before the application of the facing sheets, cylindrical plugs or stoppers are inserted into the honeycomb structure. These are then drilled through in the finished assembly.

[0006] The plugs or stoppers serve to connect and transfer force between the plate and the floor structure.

[0007] Another well-known method for creating local connections within the core structure is the subsequent insertion of inserts. For this, a defined hole is drilled into the structure, corresponding to the future insert diameter. In a second machining step, the honeycomb is milled out, for example, to 1.5 times the drilled diameter, thus creating an undercut. The insert is then inserted, and the cavity inside the honeycomb is filled with adhesive. Unlike methods where the filler material and the insert are consolidated as the outer layers cure, the subsequent bonding of inserts requires additional curing time and possibly further heat treatment, depending on the material used.

[0008] To create a three-dimensional object, it is necessary to join cut plates. An adhesive is required to create a strong bond between the two parts, regardless of the joint type. Additionally, the edge can be reinforced beforehand with filler using the method described above.

[0009] To meet required tolerances, tools are needed to hold the individual parts in position until the adhesives have fully cured. Depending on tool life and production rate, a larger number of tools are required. This number, in turn, is reflected in the NRC costs.

[0010] In established technologies for creating local reinforcements or attachment points in sandwich structures, these are usually applied before the two face sheets are attached. Typically, connectors or potting compounds are inserted into the core or core structure and cured together with the face sheets. Any necessary customization of the sandwich structure or panel must therefore be carried out at an early stage, resulting in the preparation, storage, and availability of a large number of parts.

[0011] As described at the beginning, local reinforcements in honeycomb composites are achieved according to the state of the art by filling the honeycomb cells or by inserting plugs. The latter is also conceivable for foams. However, due to the closed porosity, the introduction of filling materials is only possible after prior creation of free volume through mechanical removal. Furthermore, these methods can only be applied before the application of the facings. It is therefore not possible to subsequently adapt generic panels using these methods.

[0012] DE 690 08 745 T2 discloses a method for producing a planar sandwich material provided with local reinforcement, comprising a core material sandwiched between two reinforced face sheets, wherein the core material is a thermoplastic foamed core material or a honeycomb core material, and wherein the face sheets consist of a thermoplastic fiber-reinforced plastic and at least one local reinforcement consisting of a quantity of plastic material injected under pressure into the core material. The plastic material solidifies after injection.

[0013] FR 2 927 012 A1 discloses a method for producing a honeycomb structure with a honeycomb panel and a complementary element, wherein the honeycomb panel has a honeycomb core embedded between two cover plates. The core has cavities that are substantially perpendicular to the cover plates. According to the method, a connection zone is selected to connect the complementary element to the honeycomb panel, and the cells of the connection zone are filled with a plastic material to anchor the complementary element inside the honeycomb core. The complementary plastic element is overmolded through one of the cover plates in the connection zone to fill the cells with the plastic material and form the complementary element.

[0014] US Patent 2002 / 0157785A1 discloses a method for joining thermoplastic sandwich panels with thermoplastic welds without autoclave treatment of the joint.

[0015] The preferred connection is a double, offset connection with supporting titanium dopplers. This connection is particularly suitable for joining sections of a cryogenic tank for spacecraft.

[0016] WO 2011 / 088871 A2 discloses a method for manufacturing a sandwich component comprising a honeycomb core with multiple webs and at least one cover layer, wherein the honeycomb core is made of a cellulose-based material. The cover layer is formed from a fiber-reinforced semi-finished product with a thermoplastic material matrix, wherein the webs of the honeycomb core are partially embedded in the thermoplastic material matrix of the cover layer at the connection points, so that the sandwich component is bonded.

[0017] US 5 192 482 A discloses a planar sandwich material with local reinforcement and a core material between two reinforced layers.

[0018] The invention aims to reduce cycle times, increase flexibility, and enable specific or customer-specific differentiation as late as possible in the production of core composite components. Furthermore, it seeks to reduce the number of parts required and increase the degree of automation and output or production rate.

[0019] To solve this problem, the invention provides a method for manufacturing a reinforced core composite component according to claim 1.

[0020] Advantageous embodiments are the subject of the dependent claims.

[0021] According to one aspect, the invention creates a method according to claim 1.

[0022] In particular, the invention enables, among other things, the incorporation of fillers even with closed porosity in the core structure. According to the inventive method, for example, a foam-based core composite is subsequently provided with local connections and reinforcements. The invention also reduces cycle times. Furthermore, instead of a large number of individual parts, only a small number of generic, finished parts or core composite elements are required, which are then individually adapted or machined. Moreover, automation, for example through CNC processes, is enabled instead of manual labor. In addition, the connection surface for the pins or fiber pins remains intact in foam sandwich components reinforced with pins or studs. Preferably, the core structure is designed as a foam structure, such as foam.

[0023] Preferably, the melt is introduced under pressure.

[0024] The pressure applied when introducing the thermoplastic melt is advantageously dimensioned in such a way that it displaces the foam structure in the sub-area of ​​the core structure.

[0025] For example, in addition to pressure, temperature and viscosity of the melt are also control parameters when carrying out the process.

[0026] The core structure can also be designed as a honeycomb structure.

[0027] For example, before introducing or injecting the melt, part of the core structure can be removed in order to introduce the melt there.

[0028] Preferably, the pressure during the introduction of the melt is reduced in such a way that further advancement of the melt within the core structure is stopped by its incipient cooling and solidification at the front, and at the same time a shrinkage of the volume of the melt within the core structure is prevented.

[0029] At least one of the cover layers has at least one opening for introducing the melt into the core structure, the opening being formed as a gap and extending at least partially into or through the core structure.

[0030] The gap can, for example, be formed as a groove.

[0031] In particular, the opening can be thermoplastically closed by the melt after it has been introduced.

[0032] For example, the opening is created by drilling or milling, in order to form a gap or milling gap.

[0033] Preferably, a pressure element presses against the top layer in the area of ​​the opening when the melt is introduced.

[0034] According to the invention, the gap is created by milling, while at the same time the heated thermoplastic melt is pressed into the forming gap.

[0035] Preferably, the core composite component is cut in the area of ​​the gap after the thermoplastic melt has cooled and solidified, for example to form an edge reinforcement in the area of ​​the core structure.

[0036] Preferably in step a) a further core composite element is provided for attachment to the first core composite component, wherein the two core composite elements are positioned such that their core structures lie next to each other spaced apart and form a joining gap.

[0037] Advantageously, in step b) the heated thermoplastic melt is pressed into the joining gap in order to inject it into at least a partial area of ​​the respective core structure of both core composite elements.

[0038] Preferably, the provided core composite element is cut from a core composite panel.

[0039] Advantageously, the heated thermoplastic melt is continuously and / or circumferentially injected into the core structure along the contour of the core composite element to form edge reinforcement.

[0040] Preferably, two core composite components produced using the method are joined together in the area of ​​their edge reinforcements by thermoplastic welding.

[0041] Advantageously, a projection of a load-bearing element is arranged in the opening, which is pressed together within the opening, for example under the influence of pressure and temperature, and then the heated thermoplastic melt is injected into the opening with the projection in it in order to thermoplastically connect the core composite element to the load-bearing element.

[0042] Preferably, two or more core composite elements are spaced apart from each other and connected with at least one projection of the load-bearing element to form a reinforced component with the load-bearing element.

[0043] Preferably, several openings are formed in the core structure in such a way that, after the introduction and cooling of the thermoplastic melt, they form load paths of a bionic structure.

[0044] The method described here is used in particular to process a workpiece formed by the core composite element.

[0045] According to another aspect, the invention creates a core composite component according to claim 10.

[0046] Preferably, the core composite component is manufactured using the method according to the invention.

[0047] In particular, the core composite component is a luggage compartment or overhead stowaway compartment, or part thereof.

[0048] According to a further aspect, the invention provides an aircraft comprising a core composite component manufactured using the inventive method and / or comprising a core composite component according to the invention. Advantages, details, and features described in connection with the inventive method also apply reciprocally to the other aspects of the invention.

[0049] Exemplary embodiments of the invention are explained in more detail below with reference to the accompanying drawings. These show: Figure 1 a core composite element in schematic sectional view in various phases of the inventive method according to a first preferred embodiment; Figure 2 a core composite element in schematic sectional view in various phases of the inventive method according to a second preferred embodiment; Figures 3 to 5 two core composite elements in schematic sectional view, which are fixed to each other according to a third preferred embodiment of the inventive method; Figure 6 a core composite element in schematic sectional view, which is prepared for component joining according to a fourth preferred embodiment of the inventive method; Figures 7 and 8 the in Figure 6shown core composite element before and after joining with a second such core composite element; Figure 9 a luggage compartment or overhead stowage compartment of an aircraft in schematic spatial representation, which according to the invention is provided with a load-bearing element; Figures 10-13 various steps of fastening a load-bearing element in two opposing core composite elements of the in Fig. 9 shown luggage compartment according to a fifth embodiment of the method of the invention; and Figure 14 a schematic sectional view of a core composite component which, according to a further embodiment of the inventive method, is provided with load paths and forms a bionic structure.

[0050] In the figures, identical or corresponding elements are designated with the same reference numerals and are therefore not described again unless it appears expedient. The disclosures contained in the entire description can be applied analogously to identical parts with the same reference numerals or component designations. Furthermore, the positional designations chosen in the description, such as top, bottom, side, etc., refer to the directly described and illustrated figure and should be applied analogously to the new position if the position changes. Individual features or combinations of features from the different embodiments shown and described can also represent independent, inventive, or inventive solutions.

[0051] Figure 1The figure shows the process flow or steps in the production of a core composite component 10 in various sequential phases I to IV as a sectional view. The different phases are separated from each other in the figure by dashed lines for illustrative purposes. In this example, a core composite element 11 in the form of a foam-based core composite is subsequently provided with local connections and reinforcements.

[0052] In Phase I, the core composite element 11 is initially provided. It comprises a core structure 12, which is arranged between two relatively thin cover layers 13, 14. The core structure 12 is, for example, made of a plastic and designed as a foam structure in the form of a foam. The core structure 12 with the cover layers 13, 14 forms an undisturbed, finished foam core composite.

[0053] In Phase II, an opening 15 in the form of a bore 16 is created in the upper cover layer 13, i.e., in one side of the cover layer, in this case the upper cover layer 13. The bore 16, which is designed as a hole, extends through the cover layer 13 and, in this example, through the entire core structure 12 to the opposite side of the cover layer, which is formed by the lower cover layer 14. However, the bore 16 does not necessarily have to extend through the entire core structure 12 to the opposite side of the cover layer 14. Depending on the bore depth, the flow profile will change in the subsequent process step.

[0054] In Phase III, a heated thermoplastic melt 17 is introduced into the core structure 12 or into a section thereof, as indicated by arrow E. For this purpose, an injection nozzle 18 is placed on the bore 16. The thermoplastic melt 17, which can also be, for example, a thermoplastic hot melt adhesive, is then injected through the nozzle 18 at a defined pressure into the foam composite or foam core composite and enters the core structure 12.

[0055] By appropriately adjusting the temperature of the melt 17 to the properties of the foam forming the core structure 12, the foam is induced to collapse locally. Due to the pressure of the nozzle 18, the melt 17 progressively displaces the foam or core structure 12 during injection and, after cooling, replaces it with a thermoplastic or fully thermoplastic plug 19 formed by the solidified thermoplastic material.

[0056] The plug 19 and the foam 12 bond optimally at the front 20 of the melt during the process. This process is controlled by the pressure applied when injecting the melt 17 to achieve an optimal bond.

[0057] Once a sufficient quantity of melt 17 has been introduced into the core structure 12, the pressure, or injection pressure, is reduced to a holding pressure. This stops further advancement of the melt 17 front 20 and simultaneously prevents shrinkage of the melt 17 within the core structure 12. The process pressure increases with the injection duration, as the melt 17 at the front 20 begins to cool. In addition to pressure, the temperature and viscosity of the melt 17 are further control factors during injection. The necessary settings are adjusted so that the melt 17 displaces the foam forming the core structure 12 without causing uncontrolled collapse.

[0058] To prevent the outer skins 13 and 14 of the core composite element 11 from detaching, a hold-down device (not shown in the figure) can be provided in the injection area, i.e., near the injection nozzle 18, if necessary. In this case, the hold-down device presses the workpiece or the core composite element 11 against a support surface, similar to the presser foot of a sewing machine.

[0059] After the melt 17, or the workpiece, which is now formed by the core composite element 11 filled with the solidified thermoplastic material, has completely cooled, it can be locally machined, in particular drilled and countersunk, as shown in Phase IV of the figure. The cooled thermoplastic melt 17 within the core structure 12 now forms a local reinforcement 50 of the core composite element 11, which in this way forms a reinforced core composite component. The locally reinforced core composite component 10 is then provided with, for example, one or more local connections according to the process.

[0060] The workpiece can also be simply milled flat, for example, if only local reinforcement without a bonding function is required. In this case, the hole or borehole 16, as formed in Phase II, is thermoplastically sealed.

[0061] Fig. 2Figure 1 schematically shows the temporally successive phases I to VI in the execution of the inventive method according to a further example, wherein an edge reinforcement is formed. In the example shown, in particular, circumferential core composite edges are reinforced.

[0062] In core composites, cut edges in the composite area also represent instabilities. The process reinforces the outer contours. In the following example of the inventive process, comparable processes and materials are used as in the formation of the local reinforcement in the previously described example.

[0063] In Phase I, an undisturbed, finished foam core composite is initially provided as core composite element 11. This is designed as described above (Step 1).

[0064] In Phase II, the component undergoes initial contour milling. In the simplest case, the milling cuts only one surface layer, in this example the upper surface layer 13, and in the most extensive case, the entire core structure 12. The rear or lower surface layer 14 remains undisturbed. This creates a milling gap or groove 21, forming an opening 15, which extends through the surface layer 13 and the core structure 12 (Step 2).

[0065] In Phase III, the hot thermoplastic material 17 is pressed into the milling gap 21 (step 3). Similar pressure and temperature relationships apply to process control as those already described in [reference to previous text]. Figure 1as described. Since this example involves a circumferential reinforcement, an additional feed rate of the nozzle 18, or the nozzle feed rate, is added as a control variable in the process. The nozzle feed rate runs in the longitudinal direction of the gap 21, that is, perpendicular to the plane of the drawing. Figure 2 .

[0066] If necessary, steps 2 and 3 are combined. In this case, the progressive milling step runs in front of the injection nozzle 18. This prevents a pressure drop during the introduction of the melt 17, which cannot be compensated for with the given process parameters, from resulting in complete preparation of the milling groove 21.

[0067] The spread of melt 17 with front 20 occurs as described above. Fig. 1 described.

[0068] In Phase IV, step 4 takes place, in which the melt 17 is cooled. The melt 17 is now introduced into the core structure 12 and forms an area with solidified thermoplastic material 19, i.e., an injected edge, which is shown as a cross-section in the figure. In this way, the core composite element 11 becomes a locally reinforced core composite component 10 with a reinforcement 50. Depending on the milling depth during preparation, the profile cross-section can also develop differently. This behavior can also be used to achieve weight-optimized edge reinforcement.

[0069] In Phase V, the reinforced core composite component 10 is cut out of the carrier plate or the locally reinforced core composite component 10 in the area of ​​the solidified thermoplastic material 19. If necessary, the injection areas are milled beforehand to remove any protruding thermoplastic residue.

[0070] In Phase VI, the core composite component is divided into two separate core composite components, each with local reinforcement 50. Due to the process, their two cut edges 22 have additional edge reinforcement in the area of ​​the core structure 12, which is formed by the solidified thermoplastic material 19 or by the local reinforcement 50. It can be advantageous to use the thermoplastic area 23 of the injection in the area of ​​the cover skin or top layer 13 of the composite as additional impact protection.

[0071] Advantageously, the nozzle geometry can be modified so that the thermoplastic is introduced completely, or at least predominantly, into one cut surface. This is particularly advantageous when only one side is used later.

[0072] Based on the Figures 3 to 5A further example of the inventive method is described below, in which two core composite elements 11 are joined together. For example, the production of three-dimensional structures from flat components requires the joining of various components.

[0073] First, the components A, B to be joined, each formed as a core composite element 11 as described above, are positioned and fixed relative to each other in a tool 24, as shown in Fig. 3 shown. Ideally, a gap 25 exists between the components, which allows the subsequent injection of the thermoplastic "joining compound" formed by the thermoplastic melt. Depending on the design of the tool 24, very precise component tolerances can thus be achieved.

[0074] As in Fig. 4In the next step, the injection nozzle 18 is brought into contact with the core composite elements or components 11, and the introduction or injection of the melt 17 in the injection direction E into the gap 25 begins. The melt 17 initially fills the given gap 25. Subsequently, the melt 17 is forced under the injection pressure in the direction of the flow arrows S into the two individual components A and B. For joining, the nozzle 18 moves along a joint seam as in a welding process. To prevent a pressure loss through the existing gap 25 between the individual components A and B, i.e., to prevent the melt 17 from spreading in the gap direction and only insufficiently into the individual components A and B, the melt flow in the gap direction is, if necessary, mechanically limited by a corresponding design of the nozzle 18.

[0075] As the melt 17 displaces the foam-like core structure 12 in the edge regions, a bridge or hinge 26 made of the solidified thermoplastic material 19 is formed between the individual components after the melt 17 has cooled, as shown in Fig. 5 shown. The joined core composite elements 11 thus form a core composite component 10, which is reinforced by the cooled and thus solidified thermoplastic melt 17 or 19, the reinforcement 50 being formed by the bridge or the hinge 26.

[0076] Based on Fig. 6 A further embodiment of the method according to the invention will now be explained, in which edge preparation for joining components is carried out by means of welding.

[0077] The component, designed as a core composite element 11, is first cut out from a generic plate and provided.

[0078] A movable injection device 27 is then placed on the component edge and moves around the component 11 along its contour. The movement is in the direction of arrow V. An injection unit 28 is integrated into this device, which injects the heated thermoplastic melt 17 into the core composite element 11 (arrow E). The injection into the component edge occurs during movement V. The thermoplastic material 17 penetrates the core structure 12 in the direction of flow arrows S, i.e., on a side of the core composite element 11 that is exposed or not covered by one of the cover layers 13, 14.

[0079] After completion of the cycle of the injection device 27 and cooling of the thermoplastic melt 17, post-processing of the core composite component 10 produced by the process can take place, which contains a reinforcement 50 made of solidified thermoplastic material 19.

[0080] For example, during post-processing, preparation is carried out for joining with another, similarly designed core composite component 10, as in Fig. 7 shown. The reinforced core composite component 10 is cut in such a way that the cutting edge 29 passes through the reinforcement 50 in the area of ​​the core structure 12, and preferably not through any other area of ​​the core structure 12.

[0081] In this way, the reinforcement 50 is formed as a thermoplastic edge reinforcement.

[0082] Due to its thermoplastic edge reinforcement 50, the manufactured core composite component 10 can be used to connect to another such core composite component 10 by thermoplastic welding, as shown in Fig. 8shown. This creates a thermoplastically welded core composite component 60 made up of several reinforced core composite components 10, which has a reinforcement 50 formed by the solidified thermoplastic material 19 of both core composite components 10.

[0083] Based on the Figures 9 to 13 A further application example of the inventive method is described, in which load-bearing elements are anchored in core structures of core composite components.

[0084] This shows the Fig. 9 An overhead stowage compartment (OHSC) 30, or baggage compartment for an aircraft, is shown in a schematic spatial representation and is provided with a load-bearing element 31 according to the invention. The load-bearing element 31 serves to balance the loads occurring in the baggage compartment or OHSC 30 with the permissible deformations.

[0085] According to this embodiment of the method of the invention, the following steps are provided, which are illustrated by the Figures 10 to 13 Each of the following will be explained as a schematic sectional view showing an exemplary load-bearing element 31 between two opposing core composite elements 11 of the OHSC 30.

[0086] Figure 10 Figure 1 shows the inserted element 31 between the two core composite elements 11 in an attached, but not yet fastened, state. The load-bearing element 31 is designed as a strut or brace which has a projection 32 in the form of a pin on each of two opposite sides in order to fasten the element or strut 31 to the opposing core composite elements 11 of the OHSC 30.

[0087] The core composite elements 11 are designed as described above in the preceding embodiments and are provided for carrying out the method. Subsequently, the load-bearing element 31 is inserted between the two core composite elements 11.

[0088] In the installed state, the pins 32 project into through holes 16, which were previously formed as bores in the respective core assembly or core assembly element 11 and extend through it. The diameter of each pin 32 is smaller than the inner diameter 16 of the respective hole 16. The core assembly elements 11 each rest on a bearing surface 33 of the element 31.

[0089] The geometry and number of pins 32 are to be considered exemplary. The load-bearing element 31 is preferably made of a thermoplastic, which is, for example, fiber-reinforced. However, it can also be made of another material, such as metal.

[0090] In a next step, the pins 32 in the respective core composite element 11 are flattened, i.e., deformed, under the influence of pressure and temperature. This step is comparable to the production of a rivet head. The pressure is applied to the respective pin 32 in the direction of arrows P, causing it to deform. This state is in Fig. 11 shown.

[0091] As in Fig. 12As shown, heated thermoplastic melt 17 is injected into the holes 16 of both core composite elements 11 by means of an injection unit 18 (arrow E). The heated melt 17 penetrates, as described above for the other embodiments, through the inner surfaces of the holes 16 into adjacent areas of the core structures 12 of the core composite elements 11.

[0092] The thermoplastic melt 17 is then cooled, during which time it solidifies and, after cooling, forms a solidified thermoplastic region 23, as shown in Fig. 13As shown, by injecting and cooling the thermoplastic melt 17, the formed pin 32 is fixed to the respective core composite element 11 and thereby connected to the core composite. In this state, the solidified thermoplastic area 23 forms a local reinforcement 50. The respective core composite element 11 thus forms a core composite component 10 with its local reinforcement 50, which is locally reinforced in the area of ​​the connection of the load-bearing element 31.

[0093] The geometry of element 31 can, for example, also be formed in the form of an O-frame or C-frame with correspondingly more pins 32 for fixing.

[0094] The thermoplastic area 23 does not have to be localized to integrate the strut. The thermoplastic can also be applied as a local or linear reinforcement, independent of a load-bearing element.

[0095] Figure 14Figure 1 shows a schematic sectional view of a core composite component 70, which, according to a further embodiment of the method according to the invention, has been provided with a plurality of load paths 71, which form reinforcements. In this way, the core composite component forms a bionically designed structure.

[0096] During the manufacturing process, a core composite element 11 is provided as described above. It comprises a core structure 12, which is arranged between relatively thin cover layers 13, 14. The core structure 12 is, for example, designed as a foam structure in the form of a foam material. The core structure 12 with the cover layers 13, 14 forms an undisturbed, finished foam core composite.

[0097] The load paths 71 are formed by injection tracks for the thermoplastic or for the thermoplastic material 17. After the heated thermoplastic material 17 is injected into the injection tracks, which are designed as holes, by means of injection units 28, the thermoplastic melt 17 cools and solidifies in the injection tracks.

[0098] When applying the described method for generating bionic load paths in core composites, the load paths 71 will be visible on the milled side after completion. The opposite side remains undisturbed. The described process can, of course, also be applied to three-dimensional bodies and structures.

[0099] During the injection and curing of the thermoplastic material, it can be advantageous if the injected thermoplastic material embeds the edges of the surface layers and thickens the component beyond the surface of the respective surface layer.

[0100] The invention offers the following advantages over the prior art: Only generic sheets are required as starting materials, resulting in reduced inventory. Sheet production is simplified. Cycle times are reduced because no crosslinking of adhesives is necessary; instead, only the cooling of a melt is required. Milling of the structure is also unnecessary. Furthermore, the use of various thermoplastic materials, including fiber-reinforced ones, is possible.

[0101] Furthermore, for example, the Z-reinforcement of the foam is not damaged; instead, the Z-pins are embedded in the melt. This results in improved bonding. Waste from milling out the honeycomb or core structure can be avoided. Moreover, the process is fully automatable. Tolerance issues such as those encountered with plugs or stoppers do not arise, as the melt adapts to the component's shape.

[0102] The process is also applicable to honeycomb structures, for example. This involves displacing the honeycomb and filling the cells. Reference symbol list:

[0103] 10 Core composite component 11 Core composite element 12 Core structure 13, 14 Cover layers 15 Opening 16 Bore, hole 17 Thermoplastic melt 18 Nozzle 19 Solidified thermoplastic material, plug 20 Front 21 Gap, groove 22 Cut edges 23 Solidified thermoplastic area 24 Tool 25 Gap, joining gap 26 Bridge, hinge 27 Movable injection device 28 Injection unit 29 Cut edge 30 Luggage compartment / Overhead stowage compartment 31 Load-bearing element 32 Projection / Pin 33 Bearing surface 50 Reinforcement 60 Thermoplastic welded core composite component 70 Core composite component with load paths 71 Load paths A, B Components E Injection direction P Pressure on pin S Flow direction Movement of the injection device

Claims

1. Method for producing a locally reinforced core composite component, in particular for aircraft, comprising the steps of: a) providing at least one core composite element (11) which comprises a core structure (12) which is arranged between at least two relatively thin cover layers (13, 14), wherein the core structure (12) is in the form of a foam structure and / or honeycomb structure, wherein, at least in one of the cover layers (13, 14), there is formed at least one opening (15) for introducing the melt (17) into the core structure (12), said opening being configured as a gap (21) and extending at least partially into the core structure (12) or through the latter; b) introducing a heated thermoplastic melt (17) into one or more sub-regions of the core structure (12), wherein, during the introduction of the melt (17), a pressure-exerting element presses, in the region of the opening (15), against the cover layer (13, 14), wherein the gap (21) is produced by milling, wherein at the same time the heated thermoplastic melt (17) is pressed into the gap (21) that is forming; c) cooling the thermoplastic melt (17) in the core structure (12) in order to form a core composite component (10; 60; 70) with a local reinforcement (50; 71).

2. Method according to Claim 1, characterized in that the introduction of the thermoplastic melt (17) is carried out under pressure, wherein the pressure is of such a magnitude that said melt displaces the foam structure in the sub-region of the core structure (12).

3. Method according to either of the preceding claims, characterized in that, during the introduction of the melt (17), its pressure is reduced in such a way that further advancement of the melt (17) within the core structure is stopped by the onset of its cooling and solidification at its front (20) and at the same time shrinkage of the volume of the melt (17) within the core structure (12) is prevented.

4. Method according to one of the preceding claims, characterized in that, after the cooling and solidification of the thermoplastic melt (17), the core composite component (10) is cut in the region of the gap (21) in order to form an edge reinforcement in the region of the core structure (12).

5. Method according to one of the preceding claims, characterized in that, - in step a), provision is made of a further core composite element (11) for joining to the core composite element (11), wherein the two core composite elements (11) are positioned in such a way that their core structures (12) are situated next to one another with a spacing and form a joint gap (25); and, - in step b), the heated thermoplastic melt (17) is pressed into the joint gap (25) in order to be pressed into at least one sub-region of the respective core structure (12).

6. Method according to one of the preceding claims, characterized in that the core composite element (11) provided is cut from a core composite plate, and the heated thermoplastic melt (17) is injected into the core structure (12) continuously and / or or peripherally along the contour of the core composite element (11) in order to form an edge reinforcement.

7. Method according to Claim 6, characterized in that two core composite components (10) produced using the method are connected to one another in the region of their edge reinforcements by thermoplastic welding.

8. Method according to one of the preceding claims, characterized in that, in the opening (15), there is arranged a projection (32) of a load-bearing element (31), which projection is compressed within the opening (15) under the action of pressure and temperature, and then the heated thermoplastic melt (17) is injected into the opening (15) with the projection (32) situated therein in order to connect the core composite element (11) thermoplastically to the load-bearing element (31).

9. Method according to Claim 8, characterized in that two or more core composite elements (11) are connected, spaced apart from one another, to in each case at least one projection (32) of the load-bearing element (31) in order to form with the load-bearing element (31) a reinforced component (30).

10. Core composite component obtainable by a method according to one of the preceding claims.

11. Aircraft, characterized in that said aircraft comprises a component (30) which is produced using a method according to one of Claims 1 to 9 and / or comprises a core composite component (10, 60, 70) according to Claim 10.