DE10342183A1 - Force application region in sandwich structures e.g. for aircraft or vehicles, comprises reinforcement that connects the outer skins - Google Patents

Abstract

The region in which a force transmission part (7) is connected to a sandwich structure is reinforced by bringing together the outer skins (1, 3) and/or connecting the skins by reinforcing members (4). The reinforcing members (4) can extend beyond the force application region and can run into the force transmission part (7). An independent claim is also included for the process of removing or compressing the core material (2) in the force application region and connecting the skins by stitching. Reinforcing members (4) can be positioned by stitching prior introducing the polymeric core material (2).

Description

The The invention relates to the design and the production of force application points in core composites with in the area of the introduction point in the thickness direction of the core composite enforcing reinforcing elements according to the preamble of claim 1.

The invention is suitable for introducing forces and moments in core composite structures. The core composite structure may preferably be made of fiber-plastic composite with outer layers of textile semi-finished products ( 1 and 3 , eg fabrics, scrims, mats, etc.), a core material ( 2 , For example, polymeric foam) and a polymeric matrix material (thermoset or thermoset) exist. Core composites are layered structures consisting of relatively thin upper ( 1 ) and lower layers ( 3 ) as well as from a relatively thick core layer ( 2 ) exist low density. Due to the comparatively thin outer layers and the tensile and pressure-sensitive core material, core composite structures generally react sensitively to locally induced forces or momentary loads. Therefore, the application of force in core composite structures must be carried out according to stress, material and production requirements. The multiaxial stress state prevailing at the force introduction point can no longer be borne by the cover layers designed exclusively for membrane loads (tension, pressure, thrust). The design measures required at the force application point depend on the location and direction of the forces and on the composition of the forces acting on them. The introduction of force usually has to be done in such a way that no local instabilities (eg buckling or wrinkling of the cover layers) occur, the core layer and the cover layers are not damaged and the force introduction element does not detach from the core composite structure. This requires the largest possible and uniform distribution of the introduced forces and moments in the core composite structure. Thus, all constructive measures for the introduction of forces in sandwich structures have in common that they bring about a reduction of the local stress level by increasing the force introduction and cross-sectional areas. In addition, in some applications, the pressure-soft core material in the area of the force application point must be replaced by a pressure-resistant Ma material, so that, for example, the preload forces of screw can be endured.

to Initiation of forces and moments in core networks can additional Applied (so-called Onserts) or introduced force application elements (so-called inserts) are used. It is also possible to remove the core material in the area of the force application point and merge both cover layers, leaving a monolithic Area of fiber-plastic composite present and no additional Force introduction elements needed become. As further force introduction concepts for core composite structures can self-tapping Screws or screw inserts As well as riveting found applications, but only small Forces or Transmit moments can. Force application points are always necessary when forces and moments introduced into a structure or discharged from a structure to be and components are to be interconnected. Core composite structures of fiber-plastic composite find e.g. in the air and Space, in rail and motor vehicle construction as in shipbuilding often application.

All known applied force introduction elements (Onserts) for core composite structures made of fiber-plastic composite are connected cohesively to one of the two cover layers. All solutions This force introduction concept have the following disadvantages in common. Both cover layers are heavily loaded differently, i. the topcoat with the applied onsert is compared to opposite Cover layer significantly higher claimed. This can cause delamination between the onsert and the cover layer or between the cover layers and the core layer come. Furthermore, the tension and pressure soft core material below of the onsert not sufficiently reinforced, so that the core material exposed to high loads and the core material fail can. To avoid failure of the core layer below the onsert, gets at some solutions the core material completely in the area of the force introduction point by another material with higher substituted mechanical properties.

All known in addition introduced force introduction elements (inserts) are using the core composite structure cohesively connected. Here you can the inserts within the cover layers, between the cover and core layers or placed in the core material. Due to the purely cohesive connection can Inerts due to local attacking forces or a moment load of the entire core composite structure by failure of the adhesive bond, causing a total failure the introduction of force or a delamination between the outer layers and the core layer can occur.

All known force introduction concepts for core composite structures without additional power input tion elements have in common in the area of the force introduction point of the core material is first removed or compressed and the two cover layers are merged, so that there is a monolithic range of individual reinforcing layers of fiber-plastic composite. Subsequently, a bolt connection can be mounted in the monolithic area. In the case of all known solutions in the field of consolidation, failure of the outer layers or outside of the region of the consolidation leads to core failure or delamination between the outer layers and the core layer, since these regions do not provide additional positive and positive reinforcement of the core composite structure in the thickness direction Core composite structure have.

In the scriptures DE 100 02 281 A1 and EP 1 106 341 A2 Possibilities of a force introduction concept for core composite structures without additional force introduction element by merging the cover layers are disclosed. In these inventions, however, there is no positive and positive reinforcement of the core composite structure inside or outside the region of the cover layer combination, so that neither the resistance to delamination (peel strength) between the cover layers and the core layer can be improved nor does the core layer have a reinforcement. Thus, with these two disclosed possibilities, the typical failure behavior, delamination between the cover layers and the core layer and core failure in the area of the force introduction point, can not be improved.

In Scripture US 005741574A discloses a way in which a bolted joint can be reinforced by means of a fiber reinforcement structure incorporated into the core. This invention is based on the fact that fiber filaments are first introduced into the complete core material. Subsequently, the textile cover layers are applied to the core material and pressurized, so that the core material is compressed and the threads can penetrate into the cover layers. Thereafter, the impregnation of the core composite structure with a liquid thermosetting resin system. This is followed by the hardening process of the resin system. In the cured core composite structure, a through hole for the bolt connection is introduced. The fiber filaments in the core material should absorb the prestressing forces of the screw connection and prevent the tendency for delamination between the cover layers and the core layer in the region of the force introduction point. In this invention, only a cohesive and not a force and positive connection between the fiber threads and the entire core composite structure occurs in the force introduction region, whereby the resistance to delamination between the cover layers and the core layer in comparison to a non-positive and positive connection only slightly increased. Another disadvantage of this invention is that the complete core material of the core composite structure has sewing threads. As a result, the force introduction point learns in comparison to the rest of the core composite structure no necessary and additional reinforcement, so that the undisturbed core composite structure and the force application point are heavily loaded differently and the lightweight construction potential of core composite structures is not fully utilized. Furthermore, the core material is open in the area of the through-hole, whereby liquid or gaseous media can penetrate into the core material. These penetrated media can negatively affect the properties of the core material and even trigger a failure.

In Scripture DE 198 34 772 C2 a possibility of the connection of additionally inserted force introduction elements (inserts) with a fiber reinforcement structure consisting of individual reinforcing layers is disclosed. In this case, the insert is placed between the individual reinforcing layers and sewn by means of sewing threads in the thickness direction of the fiber reinforcement structure. The disclosed solution for binding inserts into monolithic fiber reinforcement structures consisting of individual reinforcing layers could also be used in core composite structures. In this case, the insert would be introduced between the individual reinforcing layers of one of the two cover layers and sewn with the aid of sewing threads. Subsequently, both the cover layer including the sewn insert and the other cover layer would be applied to the core layer. With the aid of a liquid impregnation method, the cover layers could be impregnated with a polymeric matrix material and the adhesive bond between the cover layers and the core layer produced so that a core composite structure made of fiber-plastic composite is present. The application of the disclosed invention to core composite structures would only effect a positive and non-positive connection between the insert and a cover layer produced by means of sewing threads. As a result, neither the resistance to delamination between the cover layers and the core layer can be increased in the area of the force introduction point nor the tension and pressure soft core material can be reinforced, whereby both typical failure modes of core composite structures can not be improved. Another disadvantage of this invention is that when introducing forces and moments in the insert, the top layer in which the insert is significantly higher stressed than the other cover layer, whereby the lightweight construction potential of core composites can not be fully utilized. In addition, the flow of force must pass from one surface layer to another over the core Material, which has low mechanical properties compared to the material of the outer layers and the weak point in the core composite structure, carried out. As a result, the core material can be stressed very high and core failure can be triggered. Thus, the strength and stiffness of this introduction of force or the entire core composite structure are mainly influenced by the low mechanical properties of the core material.

All previously known force introduction concepts for core composite structures have common that the core network structure in the area of the force introduction point insufficiently reinforced which causes core failure due to excessive tensile, compressive or shear stresses and delamination between the cover layers and the core layer may occur. Furthermore, in all known solutions of additionally applied or introduced force introduction elements no positive and positive connection the elements with the entire core composite structure. As a result, neither detachment of the Force introduction element of the core composite structure still the Delamination between the cover layers and the core layer or between the force introduction element and the cover layer is not prevented become.

The invention is based on the object to improve the mechanical properties of the force introduction point in core composites by introducing reinforcing elements in the thickness direction of the core composite structure (z direction) ( 1a and 1b ).

This object is achieved in that in the region of the force introduction point in core composites, the cover layers of the core composite are brought together and / or a force introduction element is arranged, and further at the point of introduction a reinforcement of the core composite structure is provided with in the thickness direction of the core composite interspersive reinforcing elements. By Armierungselemente the upper cover layer, the core layer and the lower cover layer are positively and positively connected in the region of the force application point. Furthermore, the force introduction element can be fastened to the core composite by means of the reinforcing elements. Armierungslemente preferably textile reinforcing structures ( 4 , eg sewing threads, fiber bundles, rovings, etc.). This invention relates to core composites with cover layers ( 1 and 3 ), preferably from semi-finished textile products (eg woven fabric, scrims, knitted fabrics, mats, etc.), and with a core layer ( 2 ), preferably of polymeric rigid foam, and optionally with a matrix material, preferably of polymeric material (thermoplastic, thermoset). The core composite structure can be produced in one of the numerous liquid composite molding (LCM) processes (eg resin injection or resin infiltration process). These types of core composite structures are reinforced in the thickness direction by a textile reinforcing structure prior to impregnation by the polymeric matrix material in the force introduction region. The production of these reinforced force application points can be done, for example, with industrial sewing technology. The introduction of the reinforcing structure, preferably sewing threads, in the thickness direction of the core composite, for example, can be done with a sewing needle. In this case, the sewing needle penetrates the entire core composite structure and, in the case of a core material made of polymer rigid foam, leaves a through hole including the reinforcing structure. In this case, the cross-sectional area of the through-hole must be sufficiently large in comparison to the cross-sectional area of the reinforcing structure so that the reinforcing structure can be impregnated with the polymeric matrix material and bonded to the core layer. The reinforcing elements may have an angle deviating from 0 ° to the z-axis within an xz or yz plane in the thickness direction of the core composite structure ( 1a and 1b ), eg with thrust-dominating load an angle of +/- 45 ° between the x- and z-axis and / or between the y- and z-axis is recommended. After the force application point and the entire core composite structure is completely reinforced with the reinforcing structure, the textile cover layers and the through hole including the reinforcing structure are impregnated in an LCM process with the polymeric matrix material, wherein at the same time the cohesive bonding of the core material takes place with the outer layers. After curing of the core composite structure impregnated with the polymeric matrix material textile reinforcing structure is unidirectional, fiber-reinforced tension / compression bars within the core material, which cause an amplification of the force application point, the core material and the entire core composite. The reinforcing structure hereby has the task of increasing the peel strength between the force introduction element and the core composite structure or between the cover layers and the core layer, preventing detachment of the force introduction element from the core composite structure and the mechanical properties of the core material (strength and stiffness characteristics in FIG Thickness direction) to improve. Due to the textile reinforcement structure, an existing crack in the boundary region of the cover and core layer can be stopped or deflected. This can improve the fail-safe behavior of force introductions for core networks. By introducing a textile reinforcing structure in the thickness direction of the core composite structure in the region of the force introduction point, the compressive and tensile strength can be perpendicular to the core in comparison to the known conventional force introduction concepts composite level, the compressive and tensile stiffness perpendicular to the core composite level, the compressive strength at the core composite level, the shear strength and stiffness and the peel strength between the outer layers and the core layer or between the force introduction element and the outer layers are increased. Furthermore, the failure behavior can be improved by the increased peel strength and by the "crack stop function" of the individual reinforcing elements, so that a sudden destruction of the force introduction can be prevented and thus so-called fail-safe behavior is present The introduction and presence of a certain number of reinforcing elements can ensure the quality assurance of force application points in core composites.

One Another advantage of this invention is that the reinforcing elements on the Force introduction point out into the force introduction point surrounding Core composite structure can extend, causing higher forces and Moments can be introduced into the core composite structure.

Around No additional Force introduction elements that adversely affect the weight of the core composite structure influence, need, can remove the core material in the area of the force application point or compressed, whereby the merging of the outer layers is made possible.

One Another advantage can be realized that the force introduction element Having one or more flanges, whereby the forces and moments over a larger area in the Core composite structure can be initiated.

In order to the force introduction element in the area of the force introduction point positively and positively connected to the entire core composite structure can be, the force introduction element has holes for receiving the reinforcing elements. This can cause a detachment the force introduction element are prevented and the peel strength between the force application element and the core composite structure are increased.

Got to due to the technical requirements of the core composite component (e.g., ship hull in shipbuilding) permeation of at least one cover layer of the core composite can be avoided, the force application element (so-called onsert) on one or both cover layers to be ordered.

Around higher personnel and to be able to introduce moments into the core network structure the force introduction element (so-called insert) also within one of the two or disposed within both cover layers become. Furthermore, the force introduction element between the two cover layers are placed, which partially or the entire core material is interspersed.

One Another advantage may be due to the application-related geometric and achieved constructive design of the force introduction element be by the force application element one or more the cover layer or on the cover layers fitting approaches, thereby initiating the forces and moments due to the larger lever arm can be improved.

With this invention, for one type of force application point in core composites, the possibility of reinforcement is that the core material in the region of the force introduction point is removed or compressed and both cover layers are brought together so that a monolithic region of fiber-plastic composite is present. Here, the upper cover layer ( 1 ) with the lower cover layer ( 3 ) in the area of the force introduction point ( 5 ) by means of a sewing technique in the thickness direction of the core composite structure introduced penetrating reinforcing elements ( 4 ) connected ( 1a and 1b ). Furthermore, the reinforcing elements ( 4 ) beyond the force introduction point ( 6 ) extend into the force introduction point surrounding core composite structure to accommodate higher forces and moments or to improve the mechanical properties ( 1c ). The reinforced force transmission without force introduction element for core composites with outer layers of textile semi-finished products ( 1 and 3 ), a nuclear material ( 2 ) and polymeric matrix material can be produced in one of the numerous LCM processes. In a step preceding the introduction of the polymeric matrix material, first the core material in the area of the force introduction point is removed or compressed. Subsequently, the two cover layers are brought together and the upper cover layer ( 1 ), the nuclear material ( 2 ) and the lower cover layer ( 3 ) in the area of force application ( 5 ) and possibly beyond ( 6 ) with a textile reinforcement structure ( 4 ) are sewn together in the thickness direction of the core composite structure using the sewing technique. Thereafter, the core composite structure including the textile reinforcing structure in an LCM process (eg resin injection or Harzinfiltrationsverfahren) with a polymeric matrix material (duroplastic or thermoplastic) impregnated and cured.

For the introduction of forces and moments can also be applied to the core composite structure force introduction element (onsert, 7 ) be used ( 2a and 2 B ). The onsert will be on one of the two ( 2a to 2f ) or on at de outer layers ( 2g ) and with the entire core composite structure in the area of the force introduction point with the aid of reinforcing elements ( 4 ) in the thickness direction of the core composite structure. To accommodate the reinforcing elements, the onsert has holes ( 8th ) on. The onsert may have a laterally projecting flange ( 9 ) exhibit ( 2c ), which is on the upper ( 1 ) or the lower cover layer ( 3 ), and also holes ( 8th ) for receiving the reinforcing elements. For better introduction of forces and moments, the reinforcing elements ( 4 ) in the thickness direction of the core composite structure beyond the onsert or the flange of the onsert ( 10 ) are incorporated in the core network structure ( 2d ). In addition, the flange of the onsert may have one or more approaches to better force and moment introduction into the core composite structure. 11 ) exhibit ( 2e and 2f ). The onsert ( 7 ) and the core composite structure are in a process step upstream of the introduction of the polymeric matrix material in the region of the force introduction point with a textile reinforcement structure ( 4 ) are sewn together in the thickness direction of the core composite structure using an industrial sewing technique. Subsequently, the impregnation and curing of the outer layers, the core layer and the textile reinforcing structure with a polymeric material in an LCM process.

Force introduction points with introduced into the core composite structure force application element (insert, 12 ) can be reinforced by the fact that the upper cover layer ( 1 ), the nuclear material ( 2 ) and the lower cover layer ( 3 ) outside the area of the insert with reinforcing elements ( 4 ) are joined together in the thickness direction of the core composite structure ( 3a and 3b ). The method for the production of force introduction points with introduced force introduction element ( 12 ) for core composites with outer layers of semi-finished textile products ( 1 and 3 ), a nuclear material ( 2 ) and polymeric matrix material provides that in a step preceding the introduction of the polymeric matrix material, the upper covering layer ( 1 ), the nuclear material ( 2 ) and the lower cover layer ( 3 ) outside the force introduction point by means of a sewing technique in the thickness direction of the core composite structure introduced textile reinforcing structure ( 4 ) are sewn together. After the introduction of the reinforcing structure, the impregnation and curing of the core composite structure with a polymeric material takes place in one of the possible LCM processes.

The insert ( 12 ) can also be combined with the core composite structure using reinforcing elements ( 4 ) in the thickness direction of the core composite structure ( 4a and 4b ). For this, the insert has holes ( 13 ) for receiving the reinforcing elements. Furthermore, the insert can contain a 4c ) laterally projecting flange ( 14 ) located within a cover layer ( 1 or 3 ), in the core layer ( 2 . 4c ) or between the cover and core layer, and holes ( 13 ) for receiving a textile reinforcing structure. The insert can also accommodate two laterally protruding and spaced flanges ( 14 ) exhibit ( 4d ), which within both outer layers ( 1 and 3 ), in the core layer ( 2 . 4d ) or between the cover layers ( 1 and 3 ) and the core layer ( 2 ) and holes ( 13 ) for receiving the reinforcing elements. For better introduction of forces and moments, the reinforcing elements ( 4 ) in the direction of the core composite structure via the insert ( 12 ) or the flange ( 14 ) of the insert ( 15 ) are incorporated in the core network structure ( 4e ).

The flange of the insert may have one or more approaches to better force and moment introduction into the core composite structure ( 16 ) exhibit ( 4f and 4g ). The method for the production of force introduction points with introduced force introduction elements ( 12 ) for core composites with outer layers of semi-finished textile products ( 1 and 3 ), a nuclear material ( 2 ) and polymeric matrix material provides that, in a step preceding the introduction of the polymeric matrix material, the inserts having the core composite structure are reinforced by means of the sewing technique in the thickness direction of the core composite structure (FIG. 4 ) are sewn. After the introduction of the reinforcing structure, the impregnation and curing of the core composite structure, including the reinforcing structure and the insert with a polymeric material, takes place in an LCM process.

The Invention is based on 13 embodiments explained. Show it:

1a shows the bottom view of a first embodiment with a force application point in core composites with merged cover layers ( 1 and 3 ), a core material removed in the force introduction area ( 2 ) and in the area of the 5 ) in the thickness direction of the core composite interspersing reinforcing elements ( 4 ).

1b shows the sectional view along line AA the 1a ,

1c shows the sectional view along line AA the 1a with a second variant for the execution of the reinforcing elements, wherein the reinforcing elements ( 4 ) beyond the force introduction point ( 6 ) extend into the force introduction point surrounding core composite structure.

2a shows the top view of a third embodiment with one on the top ( 1 ) Cover layer of the core composite structure applied force introduction element ( 7 , Onsert), wherein the onsert with the entire core composite structure in the region of the force introduction point with reinforcing elements ( 4 ) is connected in the thickness direction of the core composite structure and holes ( 8th ) for receiving the reinforcing elements ( 4 ) having.

2 B shows the sectional view along line BB of 2a ,

2c shows the sectional view along line BB of 2a with another variant for the design of the onsert, wherein the onsert a laterally projecting flange ( 9 ) having ( 2 B ), which on the upper cover layer ( 1 ), and also holes ( 8th ) for receiving the reinforcing elements.

2d shows the sectional view along line BB of 2a with a further variant for the execution of the reinforcing elements, wherein the reinforcing elements ( 4 ) beyond the force introduction point ( 10 ) extend into the force introduction point surrounding core composite structure.

2e shows the top view of a sixth embodiment with a force applied to the upper cover layer of the core composite structure force introduction element ( 7 , Onsert), which is an approach for better introduction of force and momentum into the core network ( 11 ) having.

2f shows the sectional view along line CC the 2e ,

2g shows the top view of a seventh embodiment with two on the top ( 1 ) and lower cover layer ( 3 ) of the core composite structure applied force introduction elements ( 7 , Onsert), where the two Onserts with the entire core composite structure in the area of the force introduction point with reinforcing elements ( 4 ) are connected in the thickness direction of the core composite structure and holes ( 8th ) for receiving the reinforcing elements ( 4 ) exhibit.

2h shows the sectional view according to line DD of 2g ,

3a shows the top view of an eighth embodiment with an inserted into the core composite structure force introduction element ( 12 , Insert), whereby the insert between the two outer layers ( 1 and 3 ) within the core material ( 2 ) of the core composite structure is arranged and the upper cover layer ( 1 ), the nuclear material ( 2 ) and the lower cover layer ( 3 ) outside the area of the insert with reinforcing elements ( 4 ) are interconnected in the thickness direction of the core composite structure.

3b shows the sectional view according to line EE of 3a ,

4a shows the top view of a ninth embodiment with an inserted into the core composite structure force introduction element ( 12 , Insert), whereby the insert between the two outer layers ( 1 and 3 ) within the core material ( 2 ) of the core composite structure, holes ( 13 ) for receiving the reinforcing elements ( 4 ) and is connected to the core composite structure by means of the reinforcing elements in the thickness direction of the core composite structure.

4b shows the sectional view according to line FF of 4a ,

4c shows the sectional view according to line FF of 4a with a further variant for the design of the insert, wherein the insert has a laterally projecting flange ( 14 ), which at the upper cover layer ( 1 ), holes ( 13 ) for receiving the reinforcing elements ( 4 ) and is connected to the core composite structure by means of the reinforcing elements in the thickness direction of the core composite structure.

4d shows the sectional view according to line FF of 4a with a further variant for the design of the insert, wherein the insert has two laterally projecting flanges ( 14 ), which at the top ( 1 ) and lower cover layer ( 3 ), holes ( 13 ) for receiving the reinforcing elements ( 4 ) and are connected to the core composite structure by means of the reinforcing elements in the thickness direction of the core composite structure.

4e shows the sectional view according to line FF of 4a with a further variant for the execution of the reinforcing elements, wherein the reinforcing elements ( 4 ) beyond the force introduction point ( 15 ) extend into the force introduction point surrounding core composite structure.

4f shows the top view of a thirteenth embodiment with an inserted into the core composite structure force introduction element ( 12 , Insert), where the insert has a laterally projecting flange ( 14 ), which, for better force and moment introduction into the core composite structure, has an approach ( 16 ), at the upper cover layer ( 1 ), holes ( 13 ) for receiving the reinforcing elements ( 4 ) and which is connected to the core composite structure by means of the reinforcing elements in the thickness direction of the core composite structure.

4g shows the sectional view according to line GG of 4f ,

Claims (13)

Force application point in core composites, characterized in that at the discharge point the cover layers ( 1 and 3 ) of the core composite are combined and / or a force introduction element ( 7 and 12 ) is arranged, and at the point of introduction, further a reinforcement of the core composite structure with reinforcing elements penetrating in the thickness direction of the core composite (US Pat. 4 ) is provided. Force introduction point in core composites according to claim 1, characterized in that the reinforcing elements ( 4 ) beyond the force introduction point ( 6 . 10 and 15 ) extends into the force introduction point surrounding core composite structure. Force introduction point in core composites according to one of claims 1 to 2, characterized in that the outer layers ( 1 and 3 ) from semi-finished textile products, the core layer ( 2 ) of polymeric, natural or structured core material and the reinforcing elements ( 4 ) consist of a textile reinforcing structure, and that the cover layers, the core layer and the reinforcing elements are embedded in a polymeric matrix material. Force introduction point in core composites according to one of claims 1 to 3, characterized in that the core material ( 2 ) is removed or compressed in the area of the force introduction point. Force introduction point in core composites according to one of claims 1 to 4, characterized in that the force introduction element ( 7 and 12 ) one or more flanges ( 9 and 14 ) having. Force introduction point in core composites according to one of claims 1 to 5, characterized in that the force introduction element holes ( 8th and 13 ) for receiving the reinforcing elements ( 4 ) and is connected to the core composite structure in the region of the force introduction point by means of the reinforcing elements in the thickness direction of the core composite structure. Force application point in core composites according to one of claims 1 to 6, characterized in that the force introduction element ( 7 ) on one of the two ( 1 or 3 ) or on both outer layers ( 1 and 3 ) is arranged. Force introduction point in core composites according to one of claims 1 to 7, characterized in that the force introduction element ( 12 ) within one of the two ( 1 or 3 ) or within both outer layers ( 1 and 3 ) is arranged. Force introduction point in core composites according to one of claims 1 to 8, characterized in that the force introduction element ( 12 ) between the two cover layers ( 1 and 3 ) and / or the core material ( 2 ) interspersed. Force introduction point in core composites according to one of claims 1 to 9, characterized in that the force introduction element one or more of the cover layer ( 1 or 3 ) or on the outer layers ( 1 and 3 ) attached approaches ( 11 and 16 ) having. Method for producing a force introduction point in core composites according to one of claims 1 to 4, characterized in that in the region of the force introduction point in a step preceding the introduction of the polymeric matrix material, the core material ( 2 ) is removed or compressed, the two outer layers ( 1 and 3 ) and the upper cover layer ( 1 ), the nuclear material ( 2 ) and the lower cover layer ( 3 ) in the area of the point of entry and / or beyond ( 6 ) by means of a sewing technique introduced textile reinforcing elements ( 4 ) are sewn together in the thickness direction of the core composite structure. A method for producing a force introduction point in core composites one of claims 1 to 11, characterized in that in the region of the force introduction point in a the introduction of the polymeric matrix material upstream step, the force introduction elements ( 7 and 12 ) and the core composite structure in the area of the introduction of force by means of a sewing technique introduced textile reinforcing elements ( 4 ) are sewn together in the thickness direction of the core composite structure. Method for producing a force introduction point in core composites of one of claims 1 to 10, characterized in that in the region of the force introduction point in a step preceding the introduction of the polymeric matrix material, the upper covering layer ( 1 ), the core layer ( 2 ) and the lower cover layer ( 3 ) outside the region of the force introduction element by means of a sewing technique introduced textile reinforcing elements ( 4 ) are sewn together in the thickness direction of the core composite structure.