Method for repairing a fiber composite material and repaired component

Abstract

Method for repairing a fiber composite material (1), wherein a repair section (11a-f) of a resin-impregnated carbon fiber fabric is joined to a defect (2) in a wall of the fiber composite material (1) in order to repair the defect (2), wherein the area of ​​the defect (2) is processed in such a way that an angled edge (7) in the thickness direction (D) of the wall is produced in the fiber composite material (1), and the repair section (11a-f) is connected at least via its edge to an area of ​​the inclined edge (7), wherein in the process, in addition to the repair section(s) (11a-f) connected to the inclined edge (7), a cover section (12, 14) is placed over the repaired area and its edge is spaced apart from the inclined edge (7) and attached to the surface of the fiber composite material (1), characterized by the fact that the material of the deck section (12, 14) is a different material from the material of the repair section, and the material of the deck section (12, 14) is a fiberglass-containing material.

Description

[0001] The present invention relates to a method for repairing a fiber composite material, in particular Class A surfaces, according to the preamble of claim 1 and a repaired component.

[0002] Methods for repairing fiber-reinforced composite materials in the field of aircraft construction are known from WO 99 / 54 117 A1, WO 2011 / 075 250 A1, WO 2017 / 081 456 A1, US 2014 / 0 329 043 A1, DE 10 2011 056 088A1, DE 10 2013 110 022 A1 and DE 10 2016 209 140 A1.

[0003] A generic method with the features of claim 1 is known, for example, from DE 10 2017 109 362 A1. This document describes the cosmetic repair of a thermoplastic fiber-reinforced composite material. If a component made of the fiber-reinforced composite material has a crack, this crack is first filled with a filler material. Then, a patch (repair section) is applied to the corresponding area of ​​the wall where the defect was located, so that the defect is no longer visible.

[0004] However, such a repair method is unsuitable for the repair of safety-relevant components, e.g. in automotive or aircraft construction, as it only offers an optical repair and cannot restore the structural properties of the material that have been degraded by the defect.

[0005] For complex components, such as the carbon fiber cross member for a vehicle body described in DE 10 2014 114 950 A1, such a method cannot be applied, as this does not restore the stability of the cross member.

[0006] Another fiber-reinforced composite element, in which a honeycomb structure is provided between two surface layers of a fiber-reinforced plastic, is known from JP 4 249114 B2. Such elements are also frequently used in vehicle construction, especially for the load-bearing structures of a body, such as the passenger cell.

[0007] Repairing such complex parts while maintaining structural stability largely equivalent to that of an undamaged component is not yet possible, often necessitating the replacement of entire components or assemblies. This is very costly.

[0008] Starting from this problem, the present invention proposes a method for repairing a fiber-reinforced composite material with the features of claim 1. According to a dependent aspect, a repaired component with the features of claim 18 is specified. Further advantageous embodiments of the invention are defined in the dependent claims.

[0009] The method according to the invention is characterized in that an area of ​​the defect is processed in such a way that an angled edge in the thickness direction of the wall is produced in the fiber composite material. Then a repair section, e.g. in the manner of a patch, is connected at least over its edge to an area of ​​the angled edge.

[0010] Such an inclined edge in the wall of the fiber-reinforced composite material is formed, for example, by a substantially planar surface segment which, when viewed from above, runs at an acute or oblique angle to the wall of the fiber-reinforced composite material and transitions into the surface via an edge separation line. The inclined edge is therefore provided in the thickness direction of the wall.

[0011] Because the edge is angled, the edge of the repair section can be attached to the angled edge itself. Since the edge of the repair section overlaps the edge at least partially in the area where it is attached, reinforcement of the fiber-reinforced composite material and a secure attachment of the repair section can be achieved.

[0012] Such a repair section can be designed in the manner of a patch and is, in particular, a planar section of a fiber material. According to the invention, such a repair section is a resin-impregnated fiber fabric, e.g., a prepreg material. Carbon fibers are used as the fibers. The fibers are, for example, processed into rovings, which are then, for example, woven into a fabric.

[0013] After the repair, the repaired section forms, for example, a hardened fiber composite area.

[0014] The edge of the repaired section is bonded to the beveled edge. This can be achieved by heating, and / or pressure and / or vacuum, for example in an autoclave or an oven. Such a bond can also occur at room temperature.

[0015] For example, in a first step, the beveled edge is produced, e.g., by milling or cutting. Then, for example, the repair section, made of resin-impregnated carbon fiber material, is brought into contact with the beveled edge and positioned there. This section is then baked under pressure and / or temperature in an autoclave.

[0016] Once the material has hardened, the defect is repaired.

[0017] Before the first step of creating the beveled edge, one or more further steps can be carried out. For example, a cutout can be made in the wall beforehand, with a vertical edge, the size of which is chosen, for example, so that all defective material has been removed.

[0018] It has proven advantageous to connect at least two repair sections, positioned one above the other in the thickness direction of the wall, to corresponding areas of the inclined edge, also positioned one above the other in the thickness direction of the wall, via their respective edges. Several repair sections, particularly 2, 3, 4, 10, 15 up to 100, are stacked so that their edges can each be connected to an area of ​​the inclined edge. The aforementioned number of layers can each represent an upper or lower limit. The original layer structure can be determined by flame-treating the resin.

[0019] Because several repair sections are provided on top of each other, the area of ​​the sloping edge can be filled with individual layers of the repair sections.

[0020] It is particularly advantageous that the repair sections are connected in a positionally accurate manner to corresponding layers of fiber material in the thickness direction of the wall. Accordingly, the wall of the fiber-reinforced composite material can be constructed from several superimposed layers of fabric. The material previously described for the repair section can be used for these fabric layers. These layers have, for example, the same or a similar thickness as the thickness of the repair section. The thickness can be 0.05 mm, 0.1 mm, 0.2 mm, 0.25 mm, 0.3 mm, 0.4 mm, 0.5 mm, 1 mm, 5 mm, 10 mm, 15 mm, 20 mm, or 25.0 mm. The aforementioned values ​​can each represent an upper or lower limit of a preferred thickness range. The material used for the repair section is, for example, the same material as the layer material of the fiber-reinforced composite material. This can be a woven material, in particular a resin-impregnated woven material.

[0021] In particular, a first repair section can be connected to a first area of ​​the beveled edge via its edge, and then a second repair section can be connected to a second area of ​​the beveled edge via its edge. This advantageously allows the repair sections to be sequentially joined to the corresponding area of ​​the beveled edge, thus filling the area. After the repair sections have been sequentially joined to the corresponding area of ​​the beveled edge, the component can, for example, be placed in an autoclave and heated under elevated temperatures and / or vacuum or pressure. The curing of the material can then reinforce the area where the defect was previously located.

[0022] The invention is not limited to two superimposed repair sections; rather, several, in particular 2, 3, 4, 10, 15 to 100 or any number of superimposed repair sections can be used. Preferably, these are placed one on top of the other in the direction of the slope of the edge and connected with edge areas.

[0023] Preferably, the method is carried out such that, after a defect area has been located, the area is processed to create a cutout in at least one surface layer of the fiber-reinforced composite material. This surface layer can be a surface of the wall. In a first step, the cutout can be created, for example, with a perpendicular edge, without regard to the edge orientation in the thickness direction. Subsequently, the angled edge can be produced, for example, by milling or other machining. This angled edge runs around the entire perimeter of the cutout. Alternatively, the angled edge can be created during the initial production of the cutout, without the intermediate step of producing an arbitrary edge.

[0024] The cutout is provided with a slanted edge, particularly in the thickness direction, i.e., in the depth direction of the surface layer, which therefore runs all the way around the cutout.

[0025] The chamfer of the edge does not have to be the same along the entire cutout, but can also be provided differently.

[0026] The repair section can be cut from a sheet of repair material. The repair section can be cut to a size that lies flat in a single layer perpendicular to the thickness direction and can be joined flush with the corresponding area of ​​the beveled edge. The repair section may, for example, have a surrounding edge that fits precisely into the cutout. The geometry of the repair section therefore corresponds, for example, to the geometry of the area of ​​the beveled edge to which the repair section is attached in the thickness direction. The repair section can be joined to the beveled edge via this edge.

[0027] For example, several repair sections are placed into the cutout one after the other. Since the cutout has a slanted edge in the thickness direction, the repair sections preferably also have different sizes that correspond to the size of the area of ​​the slanted edge in which they are attached. When the repair sections lie on top of each other in the cutout, their edges essentially correspond to the geometry of the slanted edge.

[0028] The repair sections can be provided as previously described, each as a prepreg material section that is laminated individually on top of the other and joined to the corresponding sections of the angled edge. Alternatively, a non-resin-impregnated fabric material can be provided, with which the cutout is filled successively, the layers being impregnated with resin only after the cutout has been filled or after the corresponding repair section has been inserted.

[0029] It has proven advantageous to cut the repair material precisely from a provided sheet of prepreg material. A dry material can also be used instead of prepreg. For example, the size of the cut repair material is chosen so that it lies flat in a layer perpendicular to the thickness direction and can be joined flush with the corresponding area of ​​the beveled edge.

[0030] According to this method, the geometry of the cutout can first be measured in the thickness direction at the location where the repair section is to be attached. Then, the repair section is cut out to the appropriate size to be inserted and attached in the specified cutout. This process is then repeated, with the repair sections being individually adjusted in size to fit the cutout and placed one on top of the other into the cutout with the angled edge, thus filling the cutout.

[0031] The hardening or baking can then take place in a single step after the cutout has been filled with the repair sections.

[0032] The sizes of the corresponding repair sections increase particularly sequentially, in the thickness direction of the inclined edge.

[0033] The aforementioned cutout can be selectively cut out to a certain depth in the fiber-reinforced composite material or the wall, so that a base surface remains visible when viewed from above. Alternatively, a continuous cutout through the fiber-reinforced composite material can also be made.

[0034] This cutout then forms a kind of hole that runs continuously across the thickness of the wall.

[0035] Any material or component that incorporates a fiber composite material can be considered a fiber composite material.

[0036] The fiber-reinforced composite material can consist of at least one surface layer of resin-embedded fibers or at least one layer of resin-embedded fabric. As previously described, the surface layer or wall, for example, contains several layers, at least in the thickness direction, which can be oriented precisely to the corresponding repair section.

[0037] The surface layer containing the fiber material can have a thickness between 20 and 0.1 mm. Other preferred thicknesses are 15 mm, 10 mm, 6 mm, 4 mm, 2 mm, and 0.5 mm. The aforementioned values ​​can each represent an upper or lower limit of a preferred thickness range. The component can also have a wall of the aforementioned thicknesses.

[0038] It has proven advantageous to use a corresponding layer of fabric for the repair section that has the same thickness, or only a thickness differing by up to 0.2 mm, in particular 0.001 mm, from the layers of fabric in the surface layer.

[0039] Provided the repair sections are inserted into the cutout in the correct position, it is advantageous to use approximately the same number of layers of repair sections to fill the cutout as there are layers of fabric in the thickness direction of the beveled edge. However, 5, 4, 3, or 2 more or fewer layers of repair sections than are provided for in the wall in the thickness direction of the beveled edge can also be used.

[0040] According to the invention, in addition to the repair section(s) connected to the inclined edge, a cover section is placed over the repaired area. The cover section is chosen to be slightly larger than the cutout, and its edge is therefore preferably spaced away from the inclined edge. This cover section can be attached to the surface of the fiber-reinforced composite material, i.e., to the surface layer. This covers the cutout filled by the repair section(s), thus ensuring a good surface finish and / or providing additional safety.

[0041] Multiple cover sections can also be layered on top of each other in the thickness direction, with the size of the cover sections increasing from the center of the surface to the visible surface of the fiber-reinforced composite material. Different cover section sizes ensure the smoothest possible transition from the original surface to the newly created, repaired surface, without any visible steps.

[0042] In particular, it is advantageous to choose a geometry for the cover section such that it extends to an edge or an invisible or non-disruptive area of ​​the component. For example, in the case of a motor vehicle bumper, the size of the cover section can be chosen so that it ends at a crease in the bumper.

[0043] According to the invention, the material of the deck section is different from the material of the repair section. It has been found that using a glass fiber-reinforced material is advantageous for the deck section. Therefore, a glass fiber-reinforced material is used according to the invention. Such a glass fiber-reinforced material can be a piece of glass fiber fabric embedded in a plastic or a free-standing piece. In contrast, a carbon fiber material, as previously described, is used for the repair section. The carbon fiber fabric forming the repair section provides exceptional stability after curing. The glass fiber material forming the deck section adapts better to different temperatures, thus preventing, for example, the formation of a surface step in the repaired area at cold temperatures or the permanent appearance of a mark due to fluctuating temperatures.

[0044] In particular, it may be that the cutout produced in the surface layer is cut out in such a way that it tapers in the thickness direction towards the surface of the fiber composite material in its cross-section, so that the slanted edge forms an acute angle to the surface.

[0045] An acute angle is an angle greater than 0° and less than 90°, especially between 30° and 85°.

[0046] Alternatively, the cutout can be made in the surface layer in such a way that it increases in cross-section towards the outside in the thickness direction towards the surface of the fiber composite material, so that the slanted edge forms an obtuse angle to the surface.

[0047] An obtuse angle is an angle greater than 90°, in particular greater than 95°, most preferably greater than 120°, but less than 180°.

[0048] The repaired area on the surface is less visible if the cutout tapers outwards in the thickness direction towards the surface of the fiber composite material in its cross-section than if the cutout widens towards the outer surface.

[0049] A cutout that tapers outwards in the thickness direction towards the surface of the fiber composite material in its cross-section can only be produced well if the cutout is accessible from the rear and the repair sections can be inserted into the cutout with the slanted surface from the rear and connected to the areas of the slanted edge.

[0050] Several such cutouts with different designs can be provided on a single component, such as a passenger compartment. Where access is possible from the rear, the cutout can be designed so that its cross-section tapers outwards towards the visible surface, and in areas where this is not possible, the cutout can be designed so that the cross-section widens outwards towards the visible surface.

[0051] It is advantageous for the fiber-reinforced composite material to be a layered material, coated on both sides with a surface layer of multilayered fiber material. The term "layer" is used here to distinguish it from the layers of woven fiber material, which, for example, are used in the respective surface layers.

[0052] These layers can correspond to the aforementioned walls. Alternatively, the entire layered material can also define such a wall in its thickness direction.

[0053] An intermediate layer with a honeycomb structure can be provided between the two surface layers, offering additional stability. The honeycomb structure can be made of metal, such as aluminum, or of cellulose, paper, or cardboard.

[0054] This honeycomb structure, which is designed as an intermediate layer, is held, for example, sandwich-like between the two surface layers, each of which can be made up of a multi-layered fiber material.

[0055] The connection to the surface layer and to the intermediate layer can be made using an adhesive or resin.

[0056] The method of the present invention can also be used to repair such complex components.

[0057] As previously described, it is not only possible to cut out a section in a surface layer that is not continuous through the component, but also to cut out a section that is continuous throughout the component.

[0058] For example, if the component is such a described sandwich component, a first surface layer is provided with a first continuous cutout and, opposite this, a second continuous cutout is cut out in the second surface layer via the intermediate layer.

[0059] The first section can be larger than the second section.

[0060] This is advantageous, for example, if the intermediate layer material, e.g. the honeycomb structure, is removed through this first cutout in order to then create the second cutout in the underlying second surface layer.

[0061] The second cutout can be designed in such a way that it increases in cross-section towards the interior of the surface layer, i.e., decreases towards the outer surface of the first surface layer, so that the slanted edge forms an acute angle to the visible outer surface.

[0062] With this design, for example, the second cutout can be filled with the corresponding repair sections from behind through the first cutout after the interlayer material has been removed. After filling the second cutout, the filled material can be cured. Then, for example, a replacement section of interlayer material is laminated back on and inserted into the gap so that it is flush with the edge area where interlayer material is still present.

[0063] Then, from the inside out or from the outside in, the first cutout is filled with the repair sections and then hardened again.

[0064] These filled-in sections can then each be covered with the previously described cover section.

[0065] In the previously described procedure, the first cutout can have a cross-section that increases towards the visible outer surface, so that the slanted edge forms an obtuse angle to the surface.

[0066] The procedure described above can be supplemented with a further inspection step.

[0067] For example, a component or fiber-reinforced composite material suspected of having a defect can be examined for defects using an inspection method. Such a method could be ultrasound, X-ray, thermographic, or visual inspection. In addition to visible cracks, such an inspection method can also detect areas where the individual layers of carbon fiber fabrics have separated from each other on the surface, for example, delaminated.

[0068] Based on this inspection, the relevant areas can be marked and it is selectively determined for the corresponding defect in which area the cutout or the beveled edge will be produced.

[0069] In particular, a marker can be applied to the surface of the component at each point where the defect was detected. The marker indicates, for example, where the section should later be cut out.

[0070] Usually, a larger area is chosen for the excision to ensure that all defects in the area have been cut away.

[0071] According to a further advantageous embodiment of the invention, the method can be carried out on site where the fiber composite material is located.

[0072] Local or on-site service means that the inspection and repair equipment is so easy to ship or transport that the defective component does not need to be returned to a specific factory. The process can also involve, for example, if the component is a motor vehicle part installed in a vehicle, the customer driving the defective vehicle to a local workshop, and any local workshop can then perform the service without the vehicle needing to be returned to the factory.

[0073] Furthermore, the inventive method can also be followed by a test step in which it is checked whether a predetermined strength or other values ​​are met after the repair.

[0074] According to a secondary aspect of the invention, a repaired component made of a fiber-reinforced composite material is also proposed. The repaired component may have been manufactured using the method described above. The component has at least one surface layer in which a cutout with an edge inclined in the thickness direction was provided, to which several layers of repair sections of a fiber material were fitted, thus repairing the component.

[0075] It is directly visible on the component whether such a cutout with a slanted edge has been filled with a multiple repair sections.

[0076] The previously described design can be selected for the repair sections and the cutouts.

[0077] The surface layer with the cutout can be the previously mentioned surface layer or any other layer containing a fiber material. Such a layer is preferably a multilayer layer consisting of several layers of woven fiber fabric, particularly carbon fiber fabric.

[0078] As previously described, each layer is connected to a corresponding repair section of appropriate size, and the cutout is filled accordingly.

[0079] The repair sections can become larger in the sequential order in which they are arranged in the cutout and can each be attached flush to the slanted edge.

[0080] In addition to the filled cutout, the component also includes a cover section over the repaired area, which is attached to the surface of the fiber composite material.

[0081] The material of the deck section is different from the material of the repair section and is a fiberglass material.

[0082] The cutout in the repaired component can be designed to enlarge outwards or inwards, so that the slanted edge has a blunt or acute angle with the surface.

[0083] The component can in particular have the layer material described above, wherein a multilayer fiber material is provided for each of the two opposing surface layers, with, for example, the honeycomb material being provided between the two surface layers.

[0084] The repaired component can be the passenger compartment of a motor vehicle, a load-bearing body structure of a motor vehicle, a panel covering, such as a door or a hood panel of a motor vehicle.

[0085] The load-bearing component can also be an aircraft fuselage or wing.

[0086] According to a further unclaimed aspect, a device for carrying out the method according to the invention is provided. For this purpose, a cutting device is provided which cuts out the section in the area of ​​the defect, and a laminating device is provided with which the repair section(s) are laminated in the cutout. In addition, an edge forming device is provided which creates the beveled edge in the cutout. The edge forming device can also be combined with the cutting device as a single unit.

[0087] Additionally, an inspection device may be provided with which the previously described inspection step, the search for defects, is carried out.

[0088] It may also include a structural testing facility with which the structure of the component is tested after repair.

[0089] The relevant equipment can be operated manually or automatically. Any configuration of the equipment can incorporate regulation or control mechanisms, allowing the process to be semi-automatic or fully automated.

[0090] Such a laminating device can also be manual laminating by a person.

[0091] In particular, it is preferred that the devices described above are robot-type machines that are connected to each other via a control unit in such a way that the process is automated.

[0092] It is advantageous that the cutout is cut out independently and then the corresponding repair sections are inserted sequentially into the area of ​​the cutout.

[0093] Further advantageous embodiments of the invention will become apparent from the following described exemplary embodiments in conjunction with the drawing.

[0094] This shows: Fig. 1a a section of a component made of a fiber composite material without defect or damage; Fig. 1b the section of the component from Fig. 1a, wherein a defect in the form of a break is provided in the component; Fig. 1c a configuration of the component from Fig. 1b after an initial relaxation incision has been made; Fig. 1d the situation after a section has been cut out of the component with a slanted edge; Fig. 1e the situation according to which several layers of repair sections in the excerpt from Fig. 1d have been inserted and are attached to a corresponding slanted edge; and Fig. 1f a situation in which, after filling the cutout, a cover section made of a material different from the material of the repair section was applied to the visible surface of the component; Fig. 2a another embodiment of a fiber composite material, wherein the in Fig. 2a shows a section of a sandwich structure with an intermediate layer having a honeycomb structure and two surface layers made of multilayer fiber material, similar to the material from the embodiment shown in Fig. 1; Fig. 2b an example of a defect in the component made of Fig. 2a; Fig. 2c the situation after a corresponding section has been cut out in the two outer surface layers of fibrous material and also in the intermediate material, wherein the in Fig. 2c, the section shown below, has already been filled with several layers of repair sections; Fig. 2d a situation, where subsequently according to the in Fig. In step 2c, a replacement section of an intermediate layer material is inserted into the cutout of the intermediate material; and Fig. 2e a situation in which also the one in the Fig. 2c and Fig. The upper section shown in 2d has been filled with repair sections; Fig. 3a to f a further embodiment with damage or repaired damage to a load-bearing body part made of carbon fiber composite material; Fig. 3a a similar situation to the embodiment described in Fig. 2b, wherein damage has formed in the component; Fig. 3b make a cut through the component to roughly cut out the damaged areas and to relieve stress on the component Fig. 3c a situation in which cutouts have been formed in the component so that all damage has been removed from the component, whereby the edge of the cutouts has not yet been chamfered; Fig. 3d the situation where the in Fig. 3c shows the lower section after it has been provided with a slanted edge and filled with several layers of repair sections; Fig. 3e a situation in which a replacement section of intermediate material is provided; Fig. 3f a situation where the in Fig. 3e The upper cutout shown, at its sloping edge, was filled with repair sections; and Fig. 4 a passenger compartment in which it has been determined by means of ultrasound where defective areas are, which have then been marked on the passenger compartment in order to carry out the repair method according to the invention.

[0095] In the Fig. Figures 1a to 1f show different steps of a process for repairing a fiber composite material.

[0096] In particular, a section of a component made of a fiber composite material 1 is shown, which (cf. Fig. 1b) exhibits a defect 2 in the form of a through crack. The component may be a motor vehicle component, an aircraft component, a bicycle component, or a component of another technical machine or system.

[0097] In particular, it can be the passenger compartment of a motor vehicle, a load-bearing body structure of a motor vehicle, a panel covering such as a door or hood panel of a motor vehicle. The load-bearing component can also be an aircraft fuselage or wing.

[0098] The component is made of several layers of 4a-f fabric material 3, arranged one above the other in the thickness direction D. The total wall thickness is approximately 2 mm; preferred wall thicknesses are between 1 and 20 mm. Generally, the wall thickness can be between 20 and 0.5 mm. Other preferred thicknesses are 15, 10, 6, 4, and 2 mm.

[0099] The individual fabric layers 4a-f can be produced using a prepreg process, in which individual resin-impregnated fabric sections are laid on top of each other, shaped accordingly, and then cured, for example, in an autoclave (under heat and / or pressure).

[0100] Alternatively, individual layers of fabric can be placed on top of each other, then soaked in resin and then solidified.

[0101] It is not necessary for the invention that the fiber composite material 1 is such a layered material consisting of several superimposed layers 4a-f. However, this is advantageous.

[0102] Carbon fibers can be used as the fiber material, but any other type of fiber, such as glass fibers or a mixture of glass and carbon fibers, is also possible. It can be any other fiber-containing material. The fibers used can be carbon fibers, glass fibers, or other fibers, or a mixture thereof. The fibers are processed, for example, into rovings, which are then woven into a fabric. The fabric or the layers 4a-f can be impregnated with resin, which is then cured.

[0103] As in Fig. As shown in 1b, defect 2 can be formed by a crack.

[0104] In a first step, for example, as in Fig. 1c shows the defect roughly cut out so that the corresponding surface wall sections 5 and 6 to be joined during repair are brought back to the same height relative to each other, so that they essentially form a planar surface.

[0105] This relaxation cut is not essential or necessary for the present invention. After the relaxation cut has been performed, it is then possible, as described in Fig. As shown in Figure 1d, an edge 7 inclined in the thickness direction is produced in the area of ​​the former defect. In the present case, Fig. Figure 1d shows a cross-sectional view in the thickness direction of the wall through the fiber composite material 1.

[0106] The angled edge, for example, defines a circumferential cutout 8 in the wall of the fiber composite material 1. The cutout 8 can be made with any tool, in particular by milling or sawing.

[0107] The cutout can be produced by first creating a preparatory cutout with vertical edges and then beveling the edges of the cutout so that the beveled edges 7, as shown in Fig. 1d shown, result.

[0108] The cutout 8 can therefore be created in a first step, without regard to the edge orientation in the thickness direction, e.g., with a perpendicular edge. Subsequently, the beveled edge 7 can be produced, e.g., by milling or other machining. This beveled edge 7 runs around the entire perimeter of the cutout. The beveled edge 7 can also be created during the initial production of the cutout, without the intermediate step of producing an arbitrary edge. The cutout 8 is thus provided with the beveled edge 7, specifically in the thickness direction, i.e., in the depth direction of the surface layer, and therefore runs around the entire perimeter of the cutout.

[0109] The chamfer of the edge does not have to be the same along the entire cutout, but can also be provided differently.

[0110] The present case concerns the one in Fig. The upper surface shown in 1a to 1f is the outer surface or visible surface 9 and the surface shown in the Fig. The surface shown on the lower side 1a to 1f is designated as the inner surface or invisible surface 10.

[0111] In the Fig. 1d to 1f are more layers than in the Fig. Figures 1a to 1c are shown. This is only to better illustrate the layered arrangement. The number of layers in the entire embodiment is to be determined from Fig. 1 cannot be changed.

[0112] In the exemplary embodiment from Fig. 1. The cutout 8 is cut out of the material in such a way that the slanted edge 7, which connects to the visible surface 9 or outer surface 9 at an acute angle, and to the inner surface 10 or the invisible surface at an obtuse angle.

[0113] This is the case because it is advantageous to keep the original damage to the visible surface as minimal as possible.

[0114] The angle of the oblique edge 7 with respect to the surface 9, 10 can be between more than 90° and less than 180°, in particular between 95° and 175° (obtuse angle) or between more than 0° and less than 90°, in particular between 5° and 85° (acute angle).

[0115] In any case, such a slope must be used that it is still possible to selectively connect the individual repair sections 11a-f with the corresponding layers 4a-f in the fiber composite material 1 in a layer-accurate manner.

[0116] This means, for example, that the in Fig. 1e, shown as the uppermost and smallest repair section in its cross-sectional direction, 11f with its edges essentially aligned with the edge of the in Fig. The top layers shown in 1e are connected to 4f.

[0117] For this purpose, a repair section is cut to a size adapted to the cutout at position 4f and then placed into the cutout from the side where it widens (from the side in Fig. 1e (shown on the lower page).

[0118] Such a repair section can be designed like a patch and is, in particular, a planar section of a fiber material. This type of repair section is a resin-impregnated fiber fabric, such as a prepreg material. Carbon fibers are used as the fibers. The fibers are processed, for example, into rovings, which are then woven into a fabric.

[0119] After the repair, the repaired section forms, for example, a hardened fiber composite area.

[0120] The edge of the repair section is joined to the beveled edge. This can be done by heating, and / or pressure and / or vacuum, for example in an autoclave or an oven. Such a joining can also take place at room temperature. Sequentially, as Fig. 1e shown, the repair sections 11a, b, c, d, e applied, so that cutout 8 is completely filled.

[0121] The corresponding repair sections 11a, b, c, d, e are cut to fit flush with the corresponding layer 4a, b, c, d, e within the fiber composite material.

[0122] Thus, the cutout 8 can be filled in its correct position using repair sections 11a, b, c, d, e, f.

[0123] For the present invention, a precise, positional connection is not necessarily required. It is entirely sufficient if the individual layers of the repair section are superimposed within the area of ​​the inclined edge 7 and connected to the edge of the inclined edge 7. In the simplest case of the invention, a repair section can be connected to the fiber-reinforced composite material in the area of ​​an inclined edge. After the cutout 8 has been filled, or separately for each individual filled repair layer, the inserted repair section 11a, b, c, d, e, f can be subjected to temperature and / or pressure treatment, for example, by treatment in an autoclave.

[0124] In Fig. Furthermore, a cover section 12 is placed and fastened on the inner surface 10. This cover section is referred to as the inner cover section because it is fastened to the inner surface, or the inner surface 10. The edges of the cover section 12 are spaced away from the cutout 8 and rest on the surface of the fiber composite material 1.

[0125] In Fig. In a further step, another deck section 14, referred to as the outer deck section, is provided on the outer surface 9. This deck section is made of a different material than the material used for the repair section and deck section 12. The material used for both the repair section and the inner deck section 12 is a carbon fiber-reinforced material, or the material from which the damaged component was originally manufactured, while the outer deck section 14 is made of a fiberglass material.

[0126] It is advantageous that the material of the deck section is different from that of the repair section. Specifically, a fiberglass-reinforced material is used for the deck section. Such a fiberglass-reinforced material can be a piece of fiberglass fabric embedded in a plastic or a free-standing piece. In contrast, a carbon fiber material, as previously described, is used for the repair section. The carbon fiber fabric forming the repair section provides exceptional stability after curing. The fiberglass material forming the deck section adapts better to varying temperatures, thus preventing, for example, the formation of a surface step in the repaired area at low temperatures. The layer structure is modeled on the original or built up quasi-isotropically. This is advantageous with regard to stability and the appearance of the repair.

[0127] In the present case, this outer deck section 14 with its edges is also provided on the outer surface 9, spaced apart from the cutout 8.

[0128] In this case, two or more outer sections arranged one above the other are particularly advantageous. It is preferable to choose a different size for each section, such that the sections become larger towards the outer surface.

[0129] This design allows for a smoother transition between the original surface of the fiber composite material and the repaired area.

[0130] In Fig. Figures 2a to 2e show a second embodiment of a component made of a fiber-reinforced composite material 1. This fiber-reinforced composite material 1 is a sandwich material. An intermediate material 17 is provided between an inner surface layer 15 and an outer surface layer 16. The intermediate material 17 can have a honeycomb structure, with the honeycombs oriented in the thickness direction of the fiber-reinforced composite material.

[0131] The intermediate material can be made of metal, such as aluminum or an alloy, or a cellulose-based material, such as paper or cardboard.

[0132] The inner surface layer 15 is called the inner surface layer because, for example, it is not visible in the component, and the outer surface layer 16 is called the outer surface layer because it is visible.

[0133] The inner and outer surface layers 15, 16 are each structured in the same way as the wall of the complete component in Fig. 1.

[0134] Therefore, this is also a multi-layered material.

[0135] For further details regarding the configurations of the surface layers 15 and 16, reference is made to what has been said in relation to the previous embodiment.

[0136] The intermediate layer material 17 is connected via a [unclear] in the Fig. 2 adhesive layers not shown are connected to the respective surface layers 15, 16.

[0137] In Fig. Figure 2b depicts a situation where the defect 2 is a crack that extends through the fiber-reinforced composite material 1. Such a crack does not have to extend all the way through, but can also be only surface damage.

[0138] In the exemplary embodiment in Fig. 2 will be, as in Fig. 2c shows the complete area in which the defect 2 is located. Fig. 2b was cut out extensively, so that no damaged areas remain in the basic component.

[0139] This can be done in a first rough pre-cut. Then, in the second, third, and fourth steps, the corresponding cutouts 22, 23, and 24 can be produced in the inner surface layer 15, the intermediate layer material 17, and the outer surface layer 16, respectively. The cutout can also be produced, as described above, first as a cutout with vertical walls perpendicular to the surface, followed by chamfering of the edges so that a chamfered edge is generated at least on one of the two cutouts 22 and 24 in the inner surface layer 15 and the outer surface layer 16, respectively. In this case, both surface layers have a chamfered edge 7.

[0140] At the in Fig. In the embodiment shown in 2c, the cutout 24 in the outer surface layer 16 is provided with a slanted edge such that the cutout tapers towards the visible surface or outer surface 18 and forms an acute angle with the outer surface 18.

[0141] The oblique edge 7 forms an obtuse angle with the inner invisible surface 19 of the outer surface layer 16.

[0142] Conversely, this is the case in the cutout in the inner surface layer 15. Here, the oblique edge 7 forms an obtuse angle with the outer visible surface 18' and an acute angle with the inner surface 19'. The cutout 22 thus tapers from the outer visible surface 18' to the inner invisible surface 19'.

[0143] The two slanted edges 7 can also have different slopes.

[0144] It is also not necessarily the case that both surface layers 15, 16 are made of the same layered material. The layers 4a, 4b, 4c, 4a', 4b', 4c' of the surface layers 15, 16 can each be made of different materials.

[0145] In Fig. Figure 2c shows that in a first step the corresponding repair sections 11a', b', c' are brought to the plant in the correct position and then connected later.

[0146] Here too, the size of the corresponding repair sections 11a', b', c' varies in the thickness direction D.

[0147] A cover section 12 is also provided on the inner non-visible surface 19 of the outer surface layer 16, similar to the cover section 12 in the embodiment in Fig. 1.

[0148] After this configuration, as it is in Fig. As shown in 2c, a replacement section 20 of an intermediate material is introduced into the section 23 of the intermediate material 17.

[0149] This is attached, for example, with an adhesive material to the inner invisible surface 19 of the outer surface layer 16 and positioned so that it has a flush surface with the intermediate material 17.

[0150] Then, as in Fig. 2e shown, in the same way as already in Fig. 1 or, for the second cutout 22 in the outer surface layer 16 as previously described, further repair sections 11a, b, c are inserted in the correct position. Here too, a cover section 12 is applied to the outer visible surface 18' of the inner surface 15. This cover section is made of a different material, namely a fiberglass material.

[0151] In Fig. Figure 3 describes a third embodiment, showing a section of a passenger compartment of a motor vehicle.

[0152] In Fig. The damaged section can be seen in 3a.

[0153] Line 21 marks an area where damage has been observed. Line 21 was applied to the surface after it had been examined, for example using a visual method, ultrasound, or X-ray, to determine the extent and location of the damage in the passenger compartment.

[0154] In Fig. Figure 3b depicts a situation in which the roughly determined parts of the damage have first been cut out.

[0155] In Fig. Figure 3c then shows a situation in which sections 22, 23, 24 are in the sandwich material, which, as in the embodiment shown, Fig. 2 are trained, have been produced.

[0156] Excerpts 22, 23, and 24 show, in this situation, how they are in Fig. As shown in 3c, the edge geometry is essentially perpendicular.

[0157] In a further step, this is then beveled, creating a slanted edge.

[0158] In Fig. The 3D representation depicts a situation where, in the (overview) lower section, the... Fig. In the sections shown in 3c, the repair sections have already been inserted with precise positioning.

[0159] It can also be seen in this figure that the (in top view) upper section is angled in such a way that the section is angled in the direction of view. Fig. 3a rejuvenates.

[0160] In Fig. Figure 3e shows a situation in which the replacement section 20 of an intermediate material has been inserted.

[0161] After this, the in Fig. 3f the in the Fig. The section 24 shown in section 3e was also filled with the corresponding repair sections in the correct position.

[0162] In Fig. Figure 4 shows a passenger cell made of a fiber composite material 1. Lines 21 can be seen there, which delineate different areas in which defects have been detected.

[0163] These defects were detected using an inspection method, in this case an ultrasound method.

[0164] At the corresponding points where the areas have been marked, the sections will later be cut out in order to repair them using the aforementioned procedure.

[0165] In particular, the present method can be used to repair so-called Class A surfaces. Class A is a standard definition of component / surface quality used in the automotive industry. A distinction is made between Class A, Class B, and Class C. Class A components are exposed exterior body parts (e.g., fenders, hoods, roofs), Class B components are less exposed (e.g., doors, sills, bumpers), and Class C components are (e.g., door sills, trunk interior).

[0166] Class A surfaces are therefore visible (freeform) surfaces in the exterior and interior areas of product development. Surfaces designated as Class A exhibit, for example, curvature consistency. Reference symbol list 1 Fiber composite material 2 defects 3 Fabric material 4a-f layers 5 wall section 6 wall section 7 slanted edge 8, 22, 23, 24 excerpt 9 Exterior surface / visible surface 10 Interior surface / invisible area 11a-f Repair section 12 Deck section 14 Deck section 15 inner surface layer 16 outer surface layer 17 Interlayer material 18, 18' outer visible surface 19, 19' inner invisible surface 20 Replacement section of an intermediate material 21 lines D Thickness direction

Claims

[1] Method for repairing a fiber composite material (1) wherein a repair section (11a-f) of a resin-impregnated carbon fiber fabric is joined to a defect (2) in a wall of the fiber composite material (1) in order to repair the defect (2) wherein the area of ​​the defect (2) is processed in such a way that an angled edge (7) in the thickness direction (D) of the wall is produced in the fiber composite material (1), and the repair section (11a-f) is connected at least via its edge to an area of ​​the inclined edge (7), wherein in the process, in addition to the repair section(s) (11a-f) connected to the inclined edge (7), a cover section (12, 14) is placed over the repaired area and its edge is spaced apart from the inclined edge (7) and attached to the surface of the fiber composite material (1), characterized by , that the material of the deck section (12, 14) is a different material from the material of the repair section, and the material of the deck section (12, 14) is a fiberglass-containing material. [2] Method according to claim 1, characterized by , that at least two repair sections (11a-f) provided one above the other in the thickness direction (D) of the wall are connected via their corresponding edges to areas of the inclined edge (7) provided one above the other in the thickness direction (D) of the wall. [3] Method according to claim 2, characterized by , that the repair sections (11a-f) are connected in the correct position with corresponding fiber material layers (4a-f) of the fiber composite material (1) in the thickness direction (D) of the wall. [4] Method according to claim 2 or 3, characterized by, that of the at least two repair sections (11a-f) provided one above the other in the thickness direction (D) of the wall, first a first repair section is connected via its edge to a first area of ​​the inclined edge (7), and then a second repair section is connected via its edge to a second area of ​​the inclined edge (7), which is provided in the thickness direction (D) of the wall above the first area of ​​the edge (7). [5] Method according to claim 4, characterized by , that in the thickness direction of the wall a multitude of repair sections (11a-f) are successively connected over their edges with corresponding areas of the inclined edge (7) lying one above the other in the thickness direction (D) of the wall. [6] Method according to any one of the preceding claims, characterized by, that the area of ​​the defect (2) is processed in such a way that a cutout (8, 22, 24) is produced at least in a surface layer of the fiber composite material (1) which is provided around its perimeter with an inclined edge (7) in the thickness direction (D) of the surface layer (15, 16), wherein the repair section (11a-f) is connected at least around its perimeter to an area of ​​the inclined edge (7). [7] Method according to claim 6, characterized by , that the repair section (11a-f) is cut from a sheet of repair material and is cut to such a size that it lies smoothly in a layer perpendicular to the thickness direction (D) and can be joined flush with the corresponding area of ​​the beveled edge (7). [8] Method according to one of claims 6 or 7, characterized by , that the cutout (8, 22, 24) is produced entirely through the fiber composite material (1). [9] Method according to any one of the preceding claims, characterized by , that several deck sections (12, 14) are provided one above the other in the thickness direction (D) wherein the size of the deck sections (12, 14) increases from the inside out to the surface of the fiber composite material (1). [10] Method according to any one of claims 6 to 9, characterized by , that the cutout (8, 22, 24) is cut out in the surface layer (15, 16) such that it tapers towards the surface of the fiber composite material (1) in its cross-section, so that the inclined edge (7) forms an acute angle with the surface. [11] Method according to any one of claims 6 to 9, characterized by, that the cutout (8, 22, 24) is cut out in the surface layer (15, 16) such that it increases in cross-section towards the surface of the fiber composite material (1) so that the inclined edge (7) forms an obtuse angle to the surface. [12] Method according to any one of claims 6 to 11, characterized by , that fiber composite material (1) is a layered material which is provided on both sides with a surface layer of a multilayer fiber material (4a-f), wherein at least in one of the two surface layers (15, 16) the cutout (22, 24) is cut out. [13] Method according to claim 12, characterized by , that in both surface layers (15, 16) at least one section (22, 24) is cut out, so that the sections (22, 24) are opposite each other. [14] Method according to claim 13, characterized by, that a first cutout (22) in a first of the two surface layers (15) is larger than a second cutout (24) in a second of the two surface layers (16). [15] Method according to claim 13 or 14, characterized by , that a first cutout (22) in a first of the two surface layers (15) is cut out in the surface layer such that it increases in cross-section towards the surface of the fiber composite material (1) so that the inclined edge (7) forms an obtuse angle to the surface; and a second cutout (24) in a second of the two surface layers (16) is cut out in the surface layer such that it tapers in cross-section towards the surface of the fiber composite material so that the inclined edge (7) forms an acute angle to the surface. [16] Method according to any one of claims 12 to 15, characterized by, that the layer material has an intermediate layer (17) with a honeycomb structure, onto which the two surface layers (15, 16) are laminated, wherein in the process in a first step in the area of ​​the defect (2) a first cutout is made in the first surface layer (15), then a third cutout (23) is made in the intermediate layer (17), and then a second cutout (24) is made in the second surface layer (16), wherein the repair sections (11a-f) are attached in the second cutout, a replacement section (20) of an intermediate layer material is connected to the repaired second surface layer (15, 16), and subsequently further repair sections (11a-f) are attached in the first cutout to repair the first surface layer. [17] Method according to any of the preceding claims, characterized bythat the procedure is carried out on site where the fiber composite material (1) is located. [18] Repaired component made of a fiber composite material, with a surface layer in which a cutout (8, 22, 24) with a slanted edge (7) in the thickness direction of a wall is repaired with several layers of repair sections (11a-f) of a resin-impregnated carbon fiber fabric, wherein the repair sections (11a-f) are connected at least circumferentially over their respective edges to a region of the slanted edge (7), wherein in addition to the repair section(s) connected to the slanted edge (7)Repair sections (11a-f) a deck section (12, 14) is placed over the repaired area and is attached to the surface of the fiber composite material (1) with its edge spaced from the inclined edge (7), wherein the material of the deck section (12, 14) is a material different from the material of the repair section (11a-f), and the material of the deck section (12, 14) is a glass fiber containing material. [19] Repaired component according to claim 18, characterized by , that a plurality of repair sections (11a-f) arranged one above the other in the cutout (8, 22, 23) and attached to corresponding areas of the inclined edge (7) have different sizes, wherein the sizes of the repair sections (11a-f) increase in their sequential order in which they are arranged in the cutout (8, 22, 23) in order to be attached flush to the inclined edge (7). [20] Repaired component according to one of claims 18 or 19, characterized by , that the cutout (8, 22, 24) is cut out in the surface layer (15, 16) in such a way that it tapers towards the surface of the fiber composite material (1) in its cross-section, so that the inclined edge (7) forms an acute angle to the surface. [21] Repaired component according to one of claims 18 or 19, characterized by , that the cutout (8, 22, 24) is cut out in the surface layer (15, 16) in such a way that it increases in cross-section towards the surface of the fiber composite material (1) so that the inclined edge (7) forms an obtuse angle to the surface. [22] Repaired component according to one of claims 18 to 21, characterized by, that the fiber composite material (1) is a layered material which is provided on both sides with a surface layer (15, 16) of a multilayer fiber material, wherein at least in one of the two surface layers (15, 16) the cutout (22, 24) is cut out. [23] Repaired component according to one of claims 18 to 22, characterized by that the repaired component is a passenger cell of a motor vehicle, a load-bearing body structure of a motor vehicle, or panel cladding of a motor vehicle.

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