EP3030405A2

EP3030405A2 - Method for producing a composite molded part, composite molded part, sandwich component, rotor blade element, and wind turbine

Info

Publication number: EP3030405A2
Application number: EP14739411.8A
Authority: EP
Inventors: Alexander Hoffmann
Original assignee: Wobben Properties GmbH
Current assignee: Wobben Properties GmbH
Priority date: 2013-08-05
Filing date: 2014-07-11
Publication date: 2016-06-15
Also published as: KR20160034390A; RU2640760C2; EP3150363B1; EP3150363A3; JP6190064B2; TW201522021A; TWI633996B; AU2014304815A1; EP3150363A2; WO2015018598A3; CA2917579C; ZA201600063B; NZ716259A; CL2016000225A1; DE102013215384A1; RU2016107713A; WO2015018598A2; CA2917579A1; CN105451973B; AR097184A1

Abstract

The invention relates to a composite molded part, in particular produced in accordance with a method according to the invention, in particular for a wind turbine, comprising: a thermoplastic plastic and a fiber composite semi-finished product. Furthermore, according to the invention, the fiber composite semi-finished product comprises a flexible, braided-structure-like fiber system, and the thermoplastic plastic is distributed as a shaping core material in the flexible, braided-structure-like fiber system of the fiber composite semi-finished product and is connected to the braided-structure-like fiber system, wherein the braided-structure-like fiber system, in the composite with the shaping core material, has fibers oriented with respect to each other in such a way that the fibers cross each other, said fibers having a fiber angle at a crossing point which is between 10° and 90°, in particular between 30° and 60°, the fibers preferably being oriented with respect to each other at a fiber angle of about 45° with a variance range of +/-5°, and wherein in the composite the braided-structure-like fiber system forms the outer functional layer of the composite molded part.

Description

Process for producing a composite molding, composite molding,

Sandwich component and rotor blade element and wind energy plant

Method for producing a composite molding according to the preamble of claim 1, in particular for a wind turbine, comprising a thermoplastic and a fiber composite semifinished product. The invention further relates to a composite molding, a sandwich component, a rotor blade element and a wind turbine.

Composite moldings are moldings made of two or more interconnected materials that are manufactured as solids of fixed geometrical dimensions. The materials occurring in the composite usually have functional properties, in particular earmarked with regard to their field of application. For the properties of the material obtained are material and possibly also geometric properties of the individual components of importance. This makes it possible to combine properties of different components with each other, whereby the composite materials find wide applications. The properties required for the final product can be adjusted as needed by choosing different starting materials for the components.

A composite component usually has properties that represent an optimized behavior of the composite molded part under load. The properties may be with respect to z. B. to assign a certain strength, stiffness or ductility. Under load, a composite molding should be an optimized behavior of the composite compared to a single component of the composite. The development of composite molded parts is basically that the required properties are optimized in combination to the lifetime in order to withstand a long-term load. Particularly in the case of rotor blades and other parts of a wind energy plant, high and widely varying load effects are exerted which, in addition, increase with an increasing part of a wind energy plant. In particular, rotor blades should withstand the static as well as the occurring dynamic loads.

Today, the rotor blades of wind turbines are mainly made of fiber composites, in the reinforcing fibers, usually as a mat, are embedded in a matrix, usually glass fiber reinforced plastic. A rotor blade is usually in one - -

Half shell sandwich construction made. Increasingly, e.g. Carbon fiber reinforced plastic used. The properties required here are on the one hand a low weight with relatively high structural strength, as well as different degrees of hardness and a tensile strength oriented on the load effect. Glass fiber reinforced or carbon fiber reinforced materials could, at least in principle and from the above viewpoints, replace the previous use of balsa wood with regard to its optimized strength.

Fiber reinforced components or composite components have fibers distributed in a laminate material, with the fibers oriented in at least one particular direction to achieve the higher quality property of the fiber composite. In any case, one can differentiate between three effective phases in the material: very tensile fibers, an initially at least relatively soft, embedding matrix, and a boundary layer connecting the two components. The fibers may typically consist of glass, carbon, ceramic but also aramid, nylon fibers, concrete fibers, natural fibers or steel fibers. The embedding matrix itself, usually polymers, has a material-specific flexural stiffness, holds the fibers in position, transfers stresses between them and protects the fibers from external mechanical and chemical influences. The boundary layer serves to transfer voltage between the two components. Problematic in fiber-reinforced composite components are possible cracking of the respective fibers in the claimed areas of the component; These can arise due to bending moments mainly due to an increased dynamic mechanical load. However, fiber reinforced components or composite components, each with a certain number of fibers in a laminate or matrix material, significantly improve the mechanical performance of the respective components. For material-specific characteristics such as shear stiffness and bending stiffness and the concentration of the fibers in a defined direction, the mechanical support properties of the respective components can be specifically adjusted in detail, in particular with respect to the tensile strength of each of the composite. One factor in the design of fiber composites is the volume ratio between fibers and matrix. The higher the proportion of fibers, the firmer, but also more brittle the composite material. In addition to the tensile strength, if the composite is subjected to pressure, the shear and bending stiffness may also play a role. In particular, it is also known in principle that a high mechanical rigidity of the composite can be achieved by means of a so-called sandwich-like composite construction with a core and one or two cover layers-following the principle of a T-support - by means of a moderately shear-resistant core and at least - -

a comparatively rigid cover layer while the composite can nevertheless be realized in lightweight construction.

Rotor blades of a wind energy plant are usually constructed of fiber-reinforced components; usually with mainly glass and / or carbon fibers in a resinous laminate matrix material. Such or other fibers may be oriented in or along the longitudinal axis of the rotor blade, the precise alignment of the fibers being usually difficult to control. In principle, however, a rotor blade can be optimized with regard to the upcoming centrifugal or gravitational forces during operation. The orientation of the fibers is indeed influenced depending on the manufacturing process. It can be decisive which type of semifinished fiber we use; these may include fabrics, scrims, mats, rovings but also fillers, pieces, needles or pigments. The processes for producing the fiber composite component are manifold. At present, methods including hand lay methods, prepreg technologies, vacuum infusion methods, filament winding methods, injection molded parts, fiber spraying, injection molded parts, extruded parts, and Sheet Molding Compounds (CMC) are known. For example, injection-molded parts are produced in a cost-effective injection molding process in which glass fibers are typically used. DE 103 36 461 describes a method for producing a rotor blade in a fiber composite construction, in which the outer contour of a rotor blade forming shells are produced and the support structures are made of fiber strands of predetermined length, which were impregnated with a thermosetting composite material and the supporting structures be transported in the shells.

US 4,242,160 presents a method in which a one-piece fiber reinforced rotor blade consists of bonded inner and outer fiber reinforced shells. The inner shell is made by joining separately formed tubular halves. The outer shell is built on the outside of the inner shell, preferably by winding a plurality of turns of fiber reinforced epoxy resin material.

A high degree of accuracy for the positioning and orientation of the fibers is guaranteed by the fiber winding method, in particular as a technique for depositing continuous fiber strands (rovings) on an at least approximately cylindrical shape, which are impregnated and cured via further method steps. For winding the fibers, the body of the component is the later form of the fiber composite material. When filament winding, one also differentiates between the lost and reusable cores, whereby the lost core can be a functional component of the construction. - -

In US 2012/0261864 a method is presented in which a fiber material is placed on the mold surface, similar to a negative image of a fiber-reinforced structure to be produced. In this case, the bundles of the fiber material are placed and aligned on the surface in such a way that by providing a low pressure, a provision of a fiber-reinforced structure takes place.

In a high-performance composite structure, fiber preforms are injected with resin and stress-strain, low-cost preforms for continuous fiber-reinforced composite components are produced. These preforms are "tailored" in the sense of stress-oriented fiber orientations, local stress-oriented fiber accumulations and outer contours. The preforms produced in this way can be processed into components in the so-called autoclave prepreg construction using conventional production processes.

The German Patent and Trademark Office has investigated the following prior art in the priority application: DE 43 00 208 A1, DE 103 36 461 A1, DE 10 2012 201 262 A1, EP 0 402 309 A1, EP 0 697 275 A2, EP 0 697 280 A1, EP 1 992 472 A1 and WO 94/19176 A1.

At this point, the invention begins, the object of which is to provide an improved method for producing a composite molding, a composite molding and a sandwich component, a rotor blade element and a wind turbine, which is improved in the prior art, but at least one of the problems described above to address. At least an alternative solution to a known in the prior art solution should be proposed. In particular with regard to the production process, a simple and controllable possibility should be offered of producing a composite molding. In particular, at least one optimized property of the composite molding with respect to the static and dynamic loads should be displayed. In particular, the production process and the composite molding with oriented and appropriately oriented fibers should counteract the attacking forces in an improved manner. In addition, the manufacturing method and a composite molding or a sandwich component, a rotor blade element and a wind turbine to use an optimized layer system, which process-specific and / or mate- rialspezifisch allows improved functionality. In particular, the composite component and the method should allow a long-term and the load effects opposing rigidity and / or strength, preferably increasing both the bending and shear stiffness. - -

The object with regard to the production method is achieved by the invention with a method of claim 1. The invention is based on a method for producing a composite molding, in particular for a wind turbine, comprising a thermoplastic and a fiber composite semi-finished product, the method comprising the steps according to the invention:

providing the thermoplastic resin and the fiber composite semifinished product with a flexible, braided-like fiber system,

- Distributing the thermoplastic material as a forming core material in the flexible braid-like fiber system of the fiber composite semi-finished product and bonding with the braid-like fiber system, wherein

- The flexible, braided-like fiber system in conjunction with the forming core material has intersecting fibers that align with each other, and

having at a crossing point a fiber angle which is between 10 ° and 90 °, in particular between 30 ° and 60 °, preferably the fibers with a fiber angle of 45 ° with a variance of +/- 5 ⁰ align each other, and where

- The braided formation-like fiber system in the composite outer functional layer of the

Formed composite part.

Preferably, the fibers align with a fiber angle of 45 ° with a variance range of +/- 5 ⁰ to each other.

Regarding the composite molding, the object is achieved by the invention with the composite molding of claim 6. The invention relates to a composite molded part, in particular produced by the aforementioned method, in particular for a wind turbine, comprising a thermoplastic and a fiber composite semifinished product. According to the invention, it is provided that

the semi-finished fiber composite has a flexible, braid-like fiber system,

- The thermoplastic material is distributed as a forming core material in the flexible, braided-like fiber system of the fiber composite semi-finished product and is connected to the braided formation-like fiber system, wherein

the braided formation-like fiber system has, in conjunction with the forming core material, intersecting fibers aligned with each other, - -

having at a crossing point a fiber angle which is between 10 ° and 90 °, in particular between 30 ° and 60 °, preferably the fibers are aligned with a fiber angle of 45 ° with a variance of +/- 5 ⁰ to each other, and where

- The braided form-like fiber system in the composite forms the outer functional layer of the composite molding.

A braided formation type fiber system is generally to be understood as any type of strand system that has some variability in intersecting fibers. Preferably, this is a braid or braid in which several strands of flexible and thus as such flexible material comprising fiber material intertwine, or a knitted fabric, in which the flexible and hence as such flexible material comprising fiber material devours with itself; also stitch-forming thread systems such as knitted fabrics are possible. Also possible are fabric-like structures in which the strands - although less preferably but possible - are wholly or partially rectangular or approximately 90 ° to each other, preferably at a crossing point have a fiber angle, which is preferably between 10 ° and 90 °, which is preferably between 30 ° and 60 °, preferably align the fibers with a fiber angle of 45 ° with a variance of +/- 10 ⁰ to each other or align with a certain other fiber angle with a variance of +/- 5 ⁰ to each other ,

In particular, such types of strand system are therefore particularly preferred, the fiber angle can also be variably adjusted, in particular sets automatically variable, depending on the size and shape of the forming core material to be introduced. Accordingly, a flexible and variably formable weave-like fiber system with a variable fiber angle is particularly preferred. Certain fiber systems support this property particularly well, such as. B. in particular a braided-like fiber system, which is selected from the group consisting of: wicker, knitted fabric.

To achieve the object with respect to the other parts or device, the invention leads to a sandwich component of claim 13 and a rotor blade element of claim 14 and a wind turbine of claim 15. The sandwich component includes at least one, in particular a plurality of composite moldings, to form a core component. The core component is at least one side, preferably two-sided, covered by at least one cover layer. In a further development, the core component of the sandwich component is covered with force-absorbing cover layers. - -

which are kept at a distance by a core material of the core component. The present development makes it possible to integrate the abovementioned combination of properties with finite maximum values with low weight in a sandwich component, which in the long run counteracts fatigue at higher loads, usually a linear increase in the nominal values. In particular, the sandwich component has improved shear and flexural strength as a result of the braided formation-type fiber system having fibers intersecting with the core forming material aligned with each other and having a fiber angle at a crossing point of between 30 ° and 30 ° 60 °, in particular wherein the fibers are aligned with a fiber angle of 45 ° with a variance range of +/- 5 ⁰ to each other

In a preferred embodiment, the rotor blade element includes at least one, in particular a plurality of composite molding as a core material. This development integrates an optimized composite molded part into a rotor blade, in particular in the production process in a half shell of the same; As a result, improved fatigue strength, in particular improved compressive strength or improved shear and bending stiffness, can be achieved. In this way, the rotor blade is optimized with regard to the pending centrifugal or gravitational forces during operation. In this case, a minimization of cracking or minimized crack propagation due to the forming core is achieved as a thermoplastic by the use of this composite component.

A wind energy installation has a tower, a nacelle and a rotor with a rotor hub and a number of rotor blades, the rotor blade having at least one rotor blade element according to the concept of the invention and / or the tower, the nacelle and / or the rotor hub a sandwich component according to the concept of the invention.

Since, due to the ever larger dimensioning of the rotor blades, ever greater loads are to be expected for the structure-dynamic behavior of the rotor blades, this can be counteracted by the material-specific parameters of the composite component according to the concept of the invention.

Basically, the concept of the invention generally applies to a composite molding, also independent of the manufacturing process. However, it has proved particularly advantageous to use a composite molding produced according to the manufacturing method according to the concept of the invention. Basically, however, too - -

other methods of manufacture are used than the claimed method of manufacture.

The invention is based on the consideration that a fiber composite material, as described in the prior art, can counteract the load effect. Higher demands on a composite component or larger geometric dimensions of certain composite components such. As rotor blades, require a new approach to a composite component, and resources and efficiency must be considered in a manufacturing process. In particular, with the braiding-like fiber system according to the invention in conjunction with the forming core material, a higher bending and shear stiffness is achieved in the composite molded part, since this has intersecting fibers which align with one another and have a fiber angle at a crossing point which is between 30 ° and 60 °, preferably align the fibers with a fiber angle of 45 ° with a variance of +/- 5 ⁰ to each other.

The invention has recognized that in the composite molded part according to the invention, in the manner of a fiber-matrix composite component, the strength and rigidity are substantially higher in the fiber direction than transversely to the fiber direction. However, since the action of the loads, such as tension or pressure, is not always perpendicular to surface normals, the effect of unidirectionally oriented fibers in the fiber composite component would be rather limited. The invention provides a functional orientation of intersecting fibers, which minimizes force or load on the component in the surface, it is provided according to the invention that align the intersecting fibers to each other and at a crossing point have a fiber angle between 30 ° and 60 °, preferably the fibers are aligned with a fiber angle of 45 ° with a variance range of +/- 5 ⁰ to each other.

Due to the variably aligning fibers, the process by which this oriented composite molded article is produced can be carried out in a technically simple and cost-effective manner.

The functional orientation makes it possible to produce a load-oriented composite molding, which maintains the process of distributing the forming core material and allows the formation of an outer layer as a functional layer. This layer is characterized as a functional layer because it opposes the functional orientation of the fibers of the load. The directional fiber layer arrangement of - -

intersecting fibers leads to a constructive increase in the mechanical properties and can meet the requirements of a composite molding.

Overall, the invention is based on the consideration that an adjustable stiffness by the choice of a suitable, flexible braiding-like fiber system and its combination with the thermoplastic material is possible. In this case, ductile properties of the matrix-the thermoplastic-as the forming core material combined with the properties of the outer functional layer-the connected functionally aligned braided structure-like fiber system-which primarily increases the strength, in particular the breaking strength, are increased.

Advantageous developments of the invention can be found in the dependent claims and specify in particular advantageous ways to realize the above-described concept within the scope of the problem and with regard to further advantages.

A particularly preferred development is based on the consideration that by using a flexible braiding-like fiber system of a fiber composite semi-finished product, a direction-oriented braiding, mesh, knitted or the like fiber structure can be made available, in particular when introducing a matrix or the like shaping core material, in particular during the manufacturing process in a manner corresponding to the shape of the core material, in order thus to adjust the functional layer significantly on the core material. This is the case, in particular, by means of a shape-changeable braiding-type fiber system having a braided, mesh, knitted or similar fibrous structure, wherein the braided, meshed, knitted or the like fibrous structure changes with its shape at the point of intersection of the filaments variable fiber angle which can be between 10 ° and 90 °, in particular can be between 30 ° and 60 °, in particular between 40 ° and 50 °, in particular in which the fibers with a fiber angle of 45 ° with a variance range of +/- 5 ⁰ to each other. In particular, in a tubular two- or three-dimensional braided-like fiber system, this results in an expandable variable cross-section so that the entire structure is expandable, stretchable and contractible independent of any flexible or flexible fibrous material upon introduction of the forming core material. Advantageous are in the range of at least 2: 1 up to 6: 1, in particular in the range of 4: 1 stretchable opening cross-sections, especially in a braid or fabric hose. - -

By a self-adjustable left choice of the directional fiber layer order and the fibers per se, the stiffness or the pressure resistance of the outer layer can be influenced. In particular, the development also makes possible a method which is inexpensive, controllable and, moreover, an improved realization of a functional composite molded part. Due to the reciprocal interactions, in particular self-adjusting shapes, the two components core material and braiding-like fiber system and their relationships to each other, the composite component receives a particularly optimized combination of properties in order to achieve a long service life with static and dynamic load effects.

Another advantage is that specific material parameters can be set by combining two materials in the core material and braiding-like fiber system; the two materials can be optimized independently. Thus, the matrix represents only the inner core without having to include additional functions such as anchoring, erosion and corrosion protection.

Unlike the usual application of fiber composites, the fiber here is the outer functional layer, which covers a shaping core. This functional layer protects the core and thus extends the possible product range of thermoplastics to less resistant grades. Since the matrix component represents the contact surface only as a shaping core, the proportion of the specific material properties can be changed by the respectively set diameter of the core. The braided formation type fiber system can specifically counteract locally by the choice of fibers, the local density and a combination of different fibers of the respective load effect, which is usually locally different due to the component. Due to the corresponding density and the separating layer formed in the composite, a protective layer can be formed and at the same time a force transmission to the interior of the core.

The method can be represented particularly advantageously by the functional alignment with one another at a 45 ° angle, since the orientation in a force parallelogram is directed counter to the acting load. The mechanism is based on the consideration that the normal components of the horizontally and vertically acting force components are divided in a parallelogram. The orientation of the fibers is thus directed against the applied force or load. The orientation through the preferred 45 ° fiber angle at the crossover point or other suitable fiber angle according to the concept of the invention may be an increased applied load - -

be absorbed the surface or this can be counteracted accordingly. At the same time, the preferred 45 ° angle, or the orientation of the braided formation-like fiber system at a 45 ° angle, is considered to be ideal for achieving particularly high torsional and shear strengths.

In a preferred embodiment, a composite molding is produced by the method described above, wherein a thermoplastic material is distributed and bonded as a forming core material in a flexible braided-like fiber system of a fiber composite semi-finished, the braided-like fiber system in combination with the forming core fibers having functional aligned with each other, in the fiber angle between 30 ° and 60 °, and wherein the aligned braided-like fiber system in combination represents an outer functional layer of the composite molded part. In particular, the composite molding of the preferred embodiment has a functional orientation at an angle of 45 °. Thus, the development provides a composite molding, which is comparable to fiber composite components, in the case, however, with a functional orientation to the outer layer, which thus causes an aligned strength. The aligned fibers at an angle between 30 ° and 60 ° or preferably at an angle of 45 ° cause the acting load, in the case of train or pressure, to be absorbed by the oppositely directed forces of the force parallelogram micromechanically. In addition, the initially flexible braided-like fiber system allows large variations of the forming core material. A manufacturing process is then no longer bound to the technical realization of the fiber composite component, but can adapt the shape of the core according to the application. Through the development of a functional, freely selectable in the form of molding has been developed. The protective fiber of the fiber composite semifinished product has a close association with the shaping thermoplastic material with functional properties, which is composed of the material characteristics of the thermoplastic material and of the flexible braided-type fiber system. In addition, this composite molded part has an additional function through the braided-type fiber system, the directed counteraction of specific loads.

In a preferred embodiment, a thermoplastic material is distributed in the flexible braided-like fiber system of the fiber composite semifinished product and bonded cohesively; This offers a possibility that the components - the thermoplastic see plastic and the fiber composite semi-finished - can connect chemically adhesive or cohesive. The effect achieved by this is an optimized layer system, which can distribute the acting forces more easily, since a smaller boundary surface for easier transfer of surface force is formed via a cohesive bond. The - -

Components are held together by atomic or molecular forces. They are thus non-releasable compounds that can be separated only by the destruction of the connecting means. A cohesive connection causes a bond that experiences no further forces under load. The outer functional layer-the aligned braid-like fiber system-can effectively perform its function through the composite. The further development can mean an additional component in the braiding-like fiber system, which exclusively entails fabric bonding, or the individual fibers can bring with them the cohesive connections. So impregnated fibers of the flexible braided-like fiber system can favor this material connection. Alternatively, a vacuum infusion production would be conceivable. This cohesive connection proves to be advantageous in terms of attack in corrosive and abrasive media.

A preferred embodiment provides that the thermoplastic material is distributed in the flexible braided-like fiber system of the fiber composite semifinished product and is positively connected; the development allows a positive connection between the thermoplastic material and the fiber half tool. In this case, the shaping core may already have surface cavities. In this case cavities must be designed in such a way that the opposing force of the outer layer is not exceeded by acting forces in order to release the composite from its positive connection again. At the same time, it would also be conceivable that in this development, the thermoplastic material is distributed in such a way that the flexible braided-like fiber system can sink in and be penetrated. As a result, a mechanical anchoring, which represents the form fit in the case allows. The combination of a material and an interlocking combination combines both positive aspects and is conceivable through this further education.

In a particularly preferred embodiment, the thermoplastic material is extruded into the flexible braided-like fiber system of the fiber composite pulp. Preferably, the method comprises the steps of providing the thermoplastic resin, in particular from an extruder, as a strand, and providing the flexible braiding-like fiber system as a tubular braided formation-like fiber system. Preferably, it is further provided that the thermoplastic material is distributed as a forming core material in the flexible braided-like fiber system of the fiber composite semi-finished by being introduced as a soft strand, in particular from the extruder, in the tube of the braided formation-like fiber system, in particular an extruded, and solidification of the soft - -

Strand forms a composite with the braided formation-like fiber system as the outer functional layer of the composite molding.

The further development offers the possibility that a thermoplastic material as a shaping core material is driven into the flexible braided formation-like fiber system and is distributed in this. It is also conceivable that a strand of a solid to viscous thermoplastic material is pressed under pressure continuously out of the shaping opening in the flexible braided-like fiber system of a fiber composite semi-finished product. This results in the shaping opening a corresponding body in theoretically any length and can thus align the flexible braided-like fiber system accordingly. Here, the aperture of the aperture is conformable to the diameter of the braid-like fiber system and allows alignment by stretching or swaging of the flexible braid-like fiber system toward the functional alignment of the fibers in the composite.

An extrusion technique is a per se known method, which, however, can be used synergistically to introduce the soft strand, in particular from the extruder, into the tube of the braiding-like fiber system, in particular to extrude it, i. directly from the extruder.

This also allows an easy implementation, which allows a controllable and cost-effective variant for the production of functional in a layer system composite molded part. In addition, the use of the extrusion process for the corresponding composite molded part makes it possible to realize complex shapes that can simultaneously implement the pressing into the flexible braided-like fiber system. The orientation of the fibers may be through the formation itself. Ultimately, this development also enables a process at higher temperatures, which favors the composite, be it material and / or form-fitting. A preferred development increases, by additional fibers in the fabric, regardless of the angle, the strength, in particular also bending and shear stiffness, of the composite molding. This refinement takes into account that the functional alignment counteracts the parallelogram of forces of the acting load, but with further forces or forces acting differently, further threads running in a different direction can absorb additional forces and increase the rigidity or strength of the composite shaped part. Thus, the operation of the outer layer of the composite molding is optimized with respect to the applied forces and has a greater tolerance with respect to the forces acting. At the same time, this training enabled - -

also a higher rigidity at the edges or corners of the composite molding by the bundling of additional threads. In addition, the orientation of the fibers can be controlled by additional fibers and densifies the functional layer formed by the braid-like fiber system.

A braid-like fiber system in the form of a tube preferably has a two-dimensional braiding structure. This development allows the positive connection without edge or gap effects of the outer functional layer. Weaknesses in the outer functional layer can be minimized by the shape of a hose and, at the same time in the manufacturing process, allow a simple process step of uniform distribution and homogeneous alignment of the composite component with the outer functional layer.

A preferred development is that the braided formation-like fiber system has the form of a tube with a three-dimensional braided structure and has additional fibers in the interior of the composite, which are functionally aligned with each other, in the fiber angle between 30 ° and 60 °, preferably 45 °. This development takes on an additional aspect, which is already realized in the fiber composite materials, the internal structures require additional strength. By incorporating a three-dimensional braiding structure, functional forces can also be generated from inside the matrix of the forming core material. Alignment of the fibers is possible in fundamentally different forms; however, it is preferred to include a load with at a fiber angle in the range 45 ° +/- 5 ° angle; especially for high Torsionsbzw. Shear forces, this angle is suitable. The development also makes it possible to optimize the thermoplastic material in its material-specific property with respect to the forces acting without additional weight. In particular, cohesive composite possibilities are conceivable here.

In a particularly preferred development, the thermoplastic resin has at least one component of the group acrylonitrile-butadiene-styrene, polyamides, polylacetate, polymethylmethacrylate, polycarbonate, polyethylene terephthalate, polyethylene, polypropylene, polystyrene, polyetheretherketone and polyvinyl chloride. By choosing the manufacturing process of the distribution, the respective thermoplastics or component or a mixture thereof, for. B. in a batch process, with their material-specific property be used to set the required properties for the respective composite molding. In addition, a mixture of different thermoplastics in homogeneous and / or locally different distribution of different thermoplastic materials may be advantageous. For example, a first - -

Number of composite moldings and a second number of composite moldings are used to represent a single sandwich member or a first number of composite moldings and a second number of composite moldings are used to represent a first and second sandwich member or rotor blade element in a rotor blade, a Built tower, a nacelle and / or a rotor hub as a core component; the first and second numbers of composite moldings may comprise different core materials and / or braid-like fiber systems. In one development, a flexible braided-like fiber system may comprise at least one component selected from the group consisting of: glass fibers, carbon fibers, aramid fibers, natural fibers, metal yarns, mono- or multifilament yarns, in particular thermoplastic yarns or generally plastic yarns made of nylon, PET, polypropylene or similar plastic. A choice of a single or a combination of one or more different types of stiff fibers may be used to specifically affect properties of the composite molding and / or to favor bonding to the core material. Advantageously, relatively high melting points of the materials, especially plastics, at or above 200 ° C and UV resistance.

A reinforcement of the thermoplastic by additional internal functionally directed fibers proves to be advantageous. This and similar measures can be used in addition to solidification of the composite molding. Corresponding mechanisms of action or calculated moments of force of the fibers-such as, for example, glass fibers and / or carbon fibers-can be used, but also a three-dimensional braided formation-like fiber system in which the thermoplastic material is distributed accordingly. These may have a certain orientation and be integrated according to the manufacturing process. A three-dimensional braided formation-like fiber system is understood to mean a braided formation-like fiber system whose two-dimensional surface is three-dimensionally crosslinked by a braiding, knitting or otherwise mesh-forming or similar braiding-like connection of additional fibers, in particular regular distribution of braided formation-like fibers, in particular via an open cross section a braided or fabric hose away. In this respect, a three-dimensional braided formation-like fiber system is to be distinguished from a two-dimensional braided formation-like fiber system, the flat, tubular, especially in the form of a braided or fabric tube - with round or square or - -

angularly rounded tube cross-sectional shapes - or curved, wholly or partially open arched, can be, and which can be used in combination with additionally loosely interspersed fibers. Embodiments of the invention will now be described below with reference to the drawings in comparison to the prior art, which e.g. is also shown described. This is not necessarily to represent the embodiments significantly, but rather than the drawing, including explanations useful, executed in a schematized and / or slightly distorted form. With regard to additions to the teachings directly recognizable from the drawing, reference is made to the relevant prior art. It should be noted that various modifications or changes may be made in the form and detail of an embodiment without departing from the general spirit of the invention. The disclosed in the description, in the drawing and in the claims features of the invention may be essential both individually and in any combination for the development of the invention. In addition, all combinations of at least two features disclosed in the description, the drawing and / or the claims fall within the scope of the invention. The general idea of the invention is not limited to the exact form or detail of the embodiment shown and described below or limited to an object which would be limited in comparison with the subject matter claimed in the claims. In the case of specified design ranges, values lying within the specified limits should also be disclosed as limit values and may be used and claimed as desired. Further advantages, features and details of the invention will become apparent from the following description of the preferred embodiments and with reference to the drawings.

In detail, the drawing shows in:

1A is a schematic representation of an embodiment of a composite molded part, wherein the thermoplastic material is shown here as a parallelepiped with a preferred flexible braiding structure;

1 B is a schematic representation of a further embodiment of a composite molding, wherein the thermoplastic material is shown as a cylindrical structure surrounded by a stocking-like braided structure.

FIG. 2 shows a schematic representation of the load acting on an upper functional layer in the form of a braided structure of a composite molding; FIG. - -

3A shows a schematic cross-section of a composite molding in still a preferred embodiment, wherein the forming core is shown as a thermoplastic and the overlying outer functional layer as a flexible braided structure.

Fig. 3B is a schematic cross section of a composite molding in still a preferred embodiment, wherein the forming core is shown as a thermoplastic and the overlying outer functional layer as a flexible braid has the form of a tube having a three-dimensional braid structure;

3C is a schematic cross-section of a composite molded article in yet a preferred embodiment with integrated functionally oriented fibers;

4 is a simplified cross-sectional view of a rotor blade of a wind turbine with a composite molding according to a preferred embodiment;

5 shows a wind energy plant;

6 is a flowchart of a preferred embodiment of a manufacturing method.

In FIGS. 1 to 4, the same reference numerals have been used for the same or similar parts or parts of the same or similar functions for the sake of simplicity.

Fig. 1 shows a composite molding 1 which is shown in the form of a cuboid as a forming core material 2A. In this case, the braiding structure 20, in this case a braided mat of glass fibers closed to form a cuboid outer casing, encloses this cuboid and shows aligned fibers at a functional fiber angle α of 45 ° to one another. The individual fibers 21 and fibers 22 show the α = 45 ° fiber angle and form on the surface a functional parallelogram of forces, which is explained in more detail with reference to FIG. In this case, a uniform distribution of the fibers is given in this illustration. However, it would also be conceivable that-for example, depending on a load distribution-the fibers 21, 22 are widened differently. Thus, a functional orientation could occur in locally denser braided structures in the areas where a higher load acts. The shape of the thermoplastic material can - -

already favoring this, serving as a formative core material. By choosing the braiding structures and their density, it is also possible to reinforce centers or, in general, areas of higher force. Fig. 1 B shows analogously a composite molding 1 'of another embodiment; in this case, the molding thermoplastic 2B was represented in the form of a cylinder surrounded by a flexible braid 20 '; in this case a braided hose made of PET. The oriented fibers correspond here to the 45 ° angle mentioned in claim 1 and are thus aligned with each other functionally, so as to represent an outer functional layer.

FIG. 2 schematically shows an externally acting force FQESAMT-in this case a tensile force-with the resulting normal forces F _A and F _s , which are divided into a force parallelogram K. The aligned fibers 21 and 22 as outer functional layer counteract here the normal forces and form in the plane of a functional layer, which counteracts the force. The fibers of the braid structure can counteract the acting force FQESAMT with an increased strength of the composite system, without a fiber 21 could yield to a transverse load, since this is absorbed by the fiber 22. In this case, further shear forces or transfer forces can be absorbed by the outer functional layer and minimized in the composite molding with appropriate material-specific properties.

FIG. 3A schematically shows, in a cross-section, a composite molding showing in the outer layer 20A a two-dimensional structure of a braid-like fiber system; Here with an aligned braiding 20 of threads 21 and 22 to a core of thermoplastic material 30 on.

In Fig. 3B, there is shown a three-dimensional orientation of a braid-like fiber system which, in addition to the outer functional layer 20A, is also aligned within filaments 23 of one of the forming core material 30 and thus forms a three-dimensional external load acting structure 20B.

In FIG. 3C, longitudinal fibers 24 are depicted within the core of the thermoplastic 30 which, in addition to the outer functional layer 20A with the fibers 21, 22 at a 45 ° angle, constitute a fiber combination 20C for protection against external stresses and additional shear and impact Torsion voltages can record. - -

In Fig. 4, a rotor blade 108 for a wind turbine 100 is shown in simplified cross-section. This rotor blade 108 comprises an upper half-shell 108.O and a lower half-shell 108.U, wherein in these shells supporting structures 10.o and 10.u are provided which can receive and remove the loads acting on the rotor blade. These support structures can be formed by rotor blade elements, for example in a sandwich construction, or by said composite moldings, just to accommodate these corresponding loads. The detail X of FIG. 4 shows such a support structure 10 with a multiplicity of composite molded parts 1, surrounded by a core material 2 surrounded by a flexible, braided-like fiber system 20, which in this example is assembled in the tightest packing to the support structure 10.

Fig. 5 shows a wind turbine 100 with a tower 102 and a nacelle 104. On the nacelle 104, a rotor 106 with three rotor blades 108 - arranged approximately analogously in the manner of a rotor blade 108 of FIG. 4- and a spinner 1 10. The rotor 106 is set in rotation by the wind in rotation and thereby drives a generator in the nacelle 104 at.

6 shows in the context of a flowchart a preferred embodiment of a manufacturing method for a composite molded part 1 or an assembly of a plurality thereof to a support structure 10 for introduction into a rotor blade 108 of a wind turbine 100. In a first step S1, a thermoplastic material and in a Step S2, a fiber composite semi-finished product in the form of a braided structure in the manner previously explained is provided. In a third step S3, the thermoplastic material is introduced as a forming core material in the flexible braiding structure and distributed therein, so that it connects to the braided structure. In the present case, in a step S3.1, the thermoplastic material is fed from a granulate mixture to an extruder and introduced in a step S3.2 at the outlet of the extruder as a soft strand into a braided hose directly. The braid tube has intersecting fibers that have a fiber angle of 45 ° at a crossing point and this travels around the still soft forming core material as it cools. As a result, the soft molding material solidifies around or on the braided hose or on the fibers thereof, so that a bond between the Gelechtschlauch and the thermoplastic material is formed with the braided hose if necessary. Wholly or at least partially, but not necessarily, on the outside thereof; the soft shaping material can remain within the contours of the braided tube or even through the mesh completely or partially penetrate to the outside; so in the latter case - -

swell and possibly even outside again put on the braided hose and enclose this.

The composite strand, which can be produced as an infinite strand overall, can be divided into a multiplicity of composite formed parts as required in a step S4 and combined to form a support structure in the manner shown in detail X of FIG. 4, for example. The support structure can be introduced in a half shell of a rotor blade 108 or in another part of a wind turbine 100 in a step S6. In the present case, the half-shells are assembled into a rotor blade blank and subjected to the further manufacturing steps until the rotor blade can be attached in a step S7 to a wind turbine 100 of the type shown in FIG.

Claims

claims

1. A method for producing a composite molding, in particular for a wind turbine, comprising a thermoplastic and a fiber composite semifinished product, the method comprising the steps:

- Distributing the thermoplastic material as a forming core material in the flexible braid-like fiber system of the fiber composite semifinished product and bonding with the braiding-like fiber system, wherein

2. The method according to claim 1, characterized in that

- The thermoplastic material, in particular from an extruder, is provided as a strand, and

- The flexible, braided-like fiber system is provided as a tubular braided-like fiber system, wherein

- The thermoplastic material is distributed as a forming core material in the flexible, braided-like fiber system of the fiber composite semi-finished by being introduced as a soft strand, in particular from the extruder, in the hose of the braided formation-like fiber system, in particular an extruded, and

- Forming a bond with the lichen structure-like fiber system as the outer functional layer of the composite molding while solidifying the soft strand.

3. The method according to claim 1 or 2, characterized in that the thermoplastic material distributed in the flexible, braided formation-like fiber system of the fiber composite semifinished product and connects cohesively with the flexible, braided formation-like fiber system.

4. The method according to any one of claims 1 to 3, characterized in that the thermoplastic material in the flexible, braided-like fiber system of Distributed fiber composite semi-finished and form-fitting with the flexible, braided-like fiber system connects.

5. The method according to any one of the preceding claims, characterized in that additional fibers in the braided formation-like fiber system and / or thermoplastic, in particular independently of said fiber angle, are introduced and increase the strength of the composite molding over a composite molding without the additional fibers.

6. composite molding, in particular produced by the method according to one of claims 1 to 5, in particular for a wind turbine, comprising a thermoplastic material and a fiber composite semifinished product, characterized in that

the semi-finished fiber composite has a flexible, braid-like fiber system,

the braided formation-like fiber system has, in conjunction with the forming core material, intersecting fibers aligned with each other,

- Which have a fiber angle in a crossing point, the between 10 ° and

Is 90 °, in particular between 30 ° and 60 °, preferably the fibers are aligned with a fiber angle of 45 ° with a variance range of +/- 5 ⁰ to each other, and wherein

7. The composite molding according to claim 6, characterized in that the braided formation-like fiber system is a fiber system selected from the group consisting of: wattle, knitted fabric, knitted fabric.

8. Composite molding according to claim 6 or 7, characterized in that the thermoplastic material is present as a strand and the flexible, braided formation-like fiber system is present as a tubular braided-like fiber system, in particular the braided formation-like fiber system has the form of a tube with a two-dimensionally oriented braided structure.

9. Composite molding according to one of claims 6 to 8, characterized in that the braided formation-like fiber system takes the form of a tube with a dreidimensio- nal braiding structure and additional fibers in the interior of the composite are functionally aligned with each other with the fiber angle between 15 ° and 90 °, in particular 30 ° and 60 °, are aligned, preferably with a fiber angle of 45 ° with a variance of +/- 5 ⁰ are aligned with each other.

10. Composite molding according to one of claims 6 to 9, characterized in that the thermoplastic material is reinforced by additional internal functionally oriented fibers.

1 1. A composite molding according to any one of claims 6 to 10, characterized in that the distributed in the flexible, braided-like fiber system thermoplastic material at least one component of the group acrylonitrile-butadiene-styrene, polyamides, polylacetate, polymethylmethacrylate, polycarbonate, polyethylene terephthalate, polyethylene, polypropylene , Polystyrene, polyetheretherketone and polyvinyl chloride.

12. The composite molding according to one of claims 6 to 1 1, characterized in that the flexible, braided-like fiber system comprises a braiding component selected from the group of braid components comprising: glass fibers, carbon fibers, aramid fibers, natural fibers, metal yarns, monofilaments and thermoplastic fibers.

13. Sandwich component, in particular for a wind energy plant, using a plurality of composite moldings according to one of claims 6 to 12 for forming a core component, characterized in that the core component is covered at least on one side of at least one cover layer.

14. rotor blade element, in particular for a wind turbine, for a rotor blade using a plurality of composite moldings according to one of claims 6 to 12 for forming a core component characterized in that the core component is surrounded by at least one rotor blade cover layer, in particular the rotor blade element according to a sandwich component Claim 13.

15. Wind energy plant comprising a tower, a nacelle and a rotor with a rotor hub and a number of rotor blades, the rotor blade having at least one rotor blade element according to claim 14 and / or the tower, the nacelle and / or the rotor hub has a sandwich component according to claim 13 ,