Assembly consisting of two fiber composite components and methods for their manufacture as well as repair methods for damaged fiber composite components

Abstract

Assembly (10) comprising two fiber composite components (11, 12), each fiber composite component (11, 12) having reinforcing fibers embedded in a matrix of thermoplastic material, and the fiber composite components (11, 12) being positioned relative to each other such that an end face of one fiber composite component (11, 12) faces an end face of another fiber composite component (11, 12), the fiber composite components (11, 12) being welded together at these end faces, the fiber composite components (11, 12) being provided with at least one reinforcement in the joint area of ​​the fiber composite components (11, 12), characterized in that the reinforcement is designed as a butt weld (14) with a short-fiber-reinforced granulate as welding filler material, the granulate being made of a thermoplastic material, in particular polyamide-6 (PA6), polyamide-66 (PA66), or polyetherimide. (PEI), polyetherketone (PEEK) and / or polyphenylene sulfide (PPS) with 10 to 50 wt.-% carbon fibers, preferably 20 to 40 wt.% carbon fibers and particularly preferably 30 wt.% carbon fibers.

Description

The present invention relates to an assembly made up of two fiber composite components, each of the fiber composite components having reinforcing fibers embedded in a matrix. The invention furthermore relates to a method for producing such an assembly and to a repair method for repair of damaged fiber composite components.In order to provide a lasting handling of energy resources, attempts are being made in today's vehicle construction to use lightweight structures. Synthetic fiber-reinforced plastics are suitable for this purpose, since they have particularly high mechanical properties and at the same time low weight. Thus, the vehicle consumption can be reduced. In contrast to known structural components made of metal, in which a plurality of different joining methods are known, only the adhesive technique is generally used for joining plastic components or fiber-reinforced plastic components. In particular, if fiber-reinforced structural components are damaged and have to be replaced or repaired, complicated repair methods are necessary, which are associated with high outlay. Until now, the defective sections have been separated out and replaced by new structural elements. The new components are connected to the existing fiber-reinforced structure via coupling elements and thus glued together in an overlapping manner. Clamping elements are used for positioning the replacement component and for adjusting the adhesive gap.Depending on the embodiment, such overlapping connections require additional installation space, which can lead to package problems. In particular when using thin-walled components which have a fiber reinforcement, the problem arises that the fiber reinforcement is interrupted at the point of separation and the entire component thereby has lower mechanical properties.WO 2010 / 130438A1 discloses a method for joining components which consist at least partially of thermoplastic material and at least one of which is long-fiber reinforced, wherein the components are welded to one another in a joining zone.DE 10 2010 025 618 A1 shows a connection arrangement of a fiber-reinforced composite component with a further, at least partially metallic component, in which the composite component has at least one metallic reinforcing fiber embedded in a plastic matrix, which protrudes beyond an end region of the composite component, wherein the at least one metallic reinforcing fiber is bonded, in particular welded or soldered, to the further component in a material-bonded manner.Proceeding from this prior art, it is an object of the present invention to specify an assembly and a method with which the disadvantages of the prior art are overcome. It is a further object of the invention to specify a repair method for fiber-reinforced plastic components, with which assemblies can be realized which have high mechanical properties at the repair point.This object is achieved by an assembly and a method having the features of the independent claims. The dependent claims represent advantageous embodiments of the invention.To achieve this object, the invention proposes an assembly of two fiber composite components, wherein each fiber composite component has reinforcing fibers which are embedded in a matrix of thermoplastic material and wherein the fiber composite components are positioned with respect to one another in such a way that an end-side end region of one fiber composite component is opposite an end-side end region of another fiber composite component. The fiber composite components are thus aligned with one another in an abutting manner and are welded to one another at these end-face end regions. In addition, at least one reinforcement can be provided in the connecting region, i.e. at the joint of the two fiber composite components. This offers the advantage that the local weakening of the assembly is compensated in this region.The reinforcement can be designed as a band which is in contact with each of the fiber composite components and connects these to one another.In addition, the band can be formed from fiber-reinforced plastic with a thermoplastic matrix. The fibers can be oriented unidirectionally in the thermoplastic matrix. This offers the advantage that the thermoplastic matrix forms a particularly good, cohesive connection with the two fiber composite components during the welding of the band.In a further alternative, a band can be arranged on each side of the component group. If accessibility on both sides at the weld seam is ensured, a strip can thereby be applied on both sides of the weld seam in order to realize a particularly strong component connection.Additionally or alternatively, the reinforcement can be designed as a butt weld seam with a short fiber-reinforced granulate as welding additive, wherein the granulate is formed from a thermoplastic material, in particular from polyamide-6 (PA6), polyamide-66 (PA66), polyetherimide (PEI), polyetherketone (PEEK) and / or polyphenylene sulfide (PPS) with 10 to 50 wt % carbon fibers, preferably 20 to 40 wt % carbon fibers and particularly preferably 30 wt % carbon fibers. Compared to pure thermoplastic welding wire, short fiber-reinforced granulate offers the advantage that the joint provides higher mechanical properties.Moreover, the butt weld may have a V-shaped cross-sectional shape and may be reinforced with a stainless steel cloth at the upper portion thereof.In a further aspect, the invention relates to a method for producing an assembly of two fiber composite components, each fiber composite component having reinforcing fibers embedded in a matrix of thermoplastic material, having the following steps:aligning the two fiber composite components with one another so that an end-side end region of one fiber composite component is opposite an end-side end region of the other fiber composite component,creating a welded connection in the joint area of the two fiber composite components, wherein a reinforcement is provided in the joint area. This offers the advantage that the butt joint requires a small installation space height compared to overlap joints.Furthermore, a tape made of fiber-reinforced plastic can be applied to the fiber composite components, so that it is in contact with both fiber composite components.In addition, the tape can be applied in such a way that it extends across the joint region across both fiber composite components and thus overlaps both fiber composite components at least partially.In a further aspect, the invention relates to a repair method for damaged fiber composite components, comprising the steps:separating a damaged location from the fiber composite component,introducing a second fiber composite component as a replacement component to the damaged location of the first fiber composite component, andproducing an assembly by connecting the two fiber composite components using a method described above.In the fiber composite components described above, the fibers can be configured as short fiber with a total length of up to 20 mm, as long fiber with a length of 20 mm to 50 mm, or as continuous fiber with an overall length greater than 50 mm.The invention is explained in more detail below with reference to the description of the figures. The claims, the figures and the description contain a multiplicity of features which are explained below in connection with exemplary embodiments of the present invention. Those skilled in the art will also consider these features individually and in other combinations to form further embodiments that are adapted to corresponding applications of the invention.It is shown in schematic representation FIG. 1 shows a side view of a connection point between two fiber composite components.FIG. 1 shows an assembly 10 in which two fiber composite components 11 and 12 are joined to one another to form the assembly 10. Each component 11, 12 has an end-face end region. This end region is arranged at the end of the component in the longitudinal direction and has a surface aligned substantially perpendicular to the longitudinal axis of the component. For joining, the components 11, 12 are aligned with respect to one another such that these end regions are situated opposite one another. As a result, joining of the components 11, 12 can take place butt-joint. In the joint region 13, the components are welded to one another with the aid of a joint weld.In order to reinforce the joint portion 13, i.e., the joint, and thereby achieve high mechanical properties, a tape 15 is applied to the joint portion 13. In this case, tapes made of thermoplastic matrix material with fibers oriented unidirectionally therein are used in particular. As welding additive for producing the butt weld 14, a granulate of thermoplastic material, in particular of polyamide-6 (PA6), polyamide-66 (PA66), polyetherimide (PEI), polyetherketone (PEEK) and / or polyphenylene sulfide (PPS), is used, which are reinforced with carbon fibers. The carbon fibers are present as short fibers, and the granulate thus has 10 to 50% by weight of carbon fibers, preferably 20 to 40% by weight of carbon fibers and particularly preferably 30% by weight of carbon fibers.Additionally or alternatively, a stainless steel fabric may be arranged in the fillet 14 for reinforcement. This stainless steel fabric is then to be provided in the upper region of the V-seam 14 in FIG. 1, in order to realize particularly good reinforcement of the weld seam.A repair method for repairing damaged fiber composite components will be explained below with reference to FIG. 1. In contrast to the illustration in FIG. 1, the fiber composite component 11 is not aligned on one side but on both sides of the second fiber composite part 12. In other words, the fiber composite part 11 is a continuous component that has a defective location at the location at which the second component 12 is introduced. This defective location is separated out, for example by sawing or bending. After removal of the defective location, a second composite component 12 is cut to size so that it fits geometrically into the cut-out location between the two parts of the first composite fiber component 11. When the second fiber composite part 12 is introduced to the damaged location of the first fiber composite part 11, end-face end regions of the fiber composite part 11 and the replacement component 12 are oriented opposite one another. A weld seam 14 is then produced in the joint regions of the two fiber composite parts 11, 12. This weld may have corresponding reinforcements as described above with reference to FIG. 1.

Claims

Assembly (10) made of two fiber composite components (11, 12), wherein each fiber composite component (11, 12) has reinforcing fibers which are embedded in a matrix made of thermoplastic material, and the fiber composite components (11, 12) are positioned relative to one another in such a way that an end-side end region of one fiber composite component (11, 12) is opposite an end-side end region of another fiber composite component (11, 12), wherein the fiber composite components (11, 12) are welded to one another at these end-side end regions, wherein at least one reinforcement is provided in the connection region of the fiber composite components (11, 12), characterized in that the reinforcement is designed as a butt weld (14), with a short-fiber-reinforced granulate as welding additive, wherein the granulate made of a thermoplastic material, in particular of polyamide-6 (PA6), polyamide-66 (PA66), polyetherimide (PEI), The invention is based on polyether ketone (PEEK) and / or polyphenylene sulfide (PPS) with 10 to 50% by weight of carbon fibers, preferably 20 to 40% by weight of carbon fibers and particularly preferably 30% by weight of carbon fibers.Assembly according to claim 1, characterised in that the butt weld has a v-shaped cross-section and is reinforced in its upper region with a stainless steel fabric.Assembly according to one of the preceding claims, characterized in that the reinforcement is designed as a band (15) which is in contact with each of the fiber composite components (11, 12) and connects these to one another.Assembly according to one of the preceding claims, characterized in that the band is formed from fibre-reinforced plastic with a thermoplastic matrix.Method for producing an assembly of two fibre composite components (11, 12), wherein each fibre composite component (11, 12) has reinforcing fibres which are embedded in a matrix of thermoplastic material, having the steps: - aligning the two fibre composite components (11, 12) with one another, such that an end-side end region of one fibre composite component (11) is opposite an end-side end region of the other fibre composite component (12), - producing a welded connection in the joint region (13) of the two fibre composite components (11, 12), wherein - a reinforcement (14, 15) is provided in the joint region (13), characterized in that the reinforcement is designed as a joint weld (14), with a short-fibre-reinforced granulate as a welding additive, wherein the granulate made of a thermoplastic material, in particular of polyamide-6 (PA6), polyamide-66 (PA66), polyetherimide (PEI), The invention is based on polyether ketone (PEEK) and / or polyphenylene sulfide (PPS) with 10 to 50% by weight of carbon fibers, preferably 20 to 40% by weight of carbon fibers and particularly preferably 30% by weight of carbon fibers.Method according to claim 5, characterised in that - a band of fibre-reinforced plastic is applied to the fibre composite components (11, 12) so that it is in contact with both fibre composite components (11, 12).Method according to claim 6, characterised in that the tape is applied across the joint area.Repair method for damaged fibre composite components, comprising the steps: - separating a damaged location from the fibre composite component (11), - introducing a second fibre composite component (12) as a replacement component to the damaged location of the first fibre composite component, and - producing an assembly by connecting the two fibre composite components (11, 12) using a method according to one of Claims 5 to 7.

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