Semi-finished product, fiber composite component and methods for its manufacture

Abstract

Fabric semi-finished product (10) which has at least two different yarn systems and is formed from a plurality of warp threads (11) as the first yarn system with a predetermined warp thread orientation and a plurality of weft threads (12, 13) as at least the second yarn system with at least one weft thread orientation different from the warp thread orientation, wherein at least a part of the warp threads (11) are elongated fiber profiles, each of which is formed from an elongated fiber material and a matrix material impregnating the fiber material and fully consolidated.

Description

[0001] The invention relates to a semi-finished fabric consisting of a plurality of warp threads and a plurality of weft threads. The invention also relates to a method for its production.

[0002] The invention also relates to a fiber composite component made from a fiber composite material with the fabric semi-finished product according to the invention. The invention also relates to a method for its production.

[0003] Due to the weight-specific strength and stiffness of fiber composite components made from fiber composite materials, such components have become indispensable in aerospace and many other applications, such as the automotive sector. During the production of a fiber composite component, a matrix material embedding the fiber material is usually cured under temperature and pressure. After curing, it forms an integral unit with the fiber material. This forces the reinforcing fibers of the fiber material into their specified direction and allows them to transfer the loads that occur in the specified direction.

[0004] Fiber composite materials from which such fiber composite components are manufactured generally have two main components: a fiber material and a matrix material. In addition, other secondary components may be used, such as binder materials or additional functional elements to be integrated into the component. If dry fiber materials are provided for production, the matrix material of the fiber composite is infused into the fiber material during the manufacturing process using an infusion process, through which the dry fiber material is impregnated with the matrix material. This usually occurs due to a pressure difference between the matrix material and the fiber material, for example, by evacuating the fiber material using a vacuum pump.In contrast, fiber composite materials are also known in which the fiber material is already pre-impregnated with the matrix material (so-called prepregs).

[0005] A wide variety of materials can be considered as fiber materials for such fiber composites. For example, quasi-endless, ribbon-like fiber materials such as rovings, towes, or tapes are often used in automated laying processes. However, woven structures, known as fiber fabrics, are also used in practice as fiber materials for the production of fiber composite components. A fabric is a textile sheet made up of at least two, usually different, thread systems. The first thread system is usually referred to as the warp threads, while the second thread system is referred to as the weft threads. The warp and weft threads are interwoven in a weaving process using various weaving patterns, so that the warp and weft threads cross depending on their orientation.

[0006] A significant disadvantage of such semi-finished fabrics is the often complicated handling of the pliable fabrics during the draping process. The semi-finished fabric is usually picked up manually and placed into a tool, ensuring that the semi-finished fabric is fully seated on the forming tool surface. This is the only way to ensure the final component geometry.

[0007] A further disadvantage is the risk of delamination due to draping errors caused by the difficult handling of the pliable fabric semi-finished products, which is one of the most serious failure modes of fiber-reinforced plastic constructions. Delamination results in delamination processes between two semi-finished layers, resulting in a loss of optimal adhesion. During the infusion process, resin accumulations can occur, which can also negatively impact the strength and rigidity of the entire component.

[0008] DE 10 2016 013 513 A1 discloses a method for manufacturing a pressure tank and initially has nothing in common with the production of a semi-finished fabric. The technical teaching of D1 discloses that the pressure tank is to be assembled from a plurality of tank elements. The tank elements are woven together using fiber threads, specifically in the manner of a fabric, to firmly connect the tank elements to one another. The production of such a pressure tank takes place using a system similar to a loom.

[0009] It is therefore an object of the present invention to provide an improved fabric semi-finished product, fiber composite component and an improved method for its production, with which the disadvantages known from the prior art can be avoided.

[0010] The object is achieved according to the invention with the semi-finished fabric according to claim 1, the fiber composite component according to claim 8, the method for producing a semi-finished fabric according to claim 9, and the method for producing a fiber composite component according to claim 15. Advantageous embodiments of the invention can be found in the corresponding subclaims.

[0011] According to claim 1, a semi-finished fabric is proposed which has at least two different thread systems and is formed from a plurality of warp threads as the first thread system and a plurality of weft threads as at least the second thread system. Warp threads have a warp thread orientation which is different from the orientation of the weft threads (weft thread orientation). For the purposes of the present invention, the warp threads and their warp thread orientation are regarded as the reference orientation, so that the warp thread orientation has an angle of 0°. The weft thread orientation of the weft threads has an angle which is different from the reference orientation of the warp threads, i.e. different from 0°. As will be shown later, with regard to the warp thread orientation, the weft threads can have an orientation of 90° or + / - 45°. The warp threads and weft threads are woven or interwoven with one another in the manner of a woven fabric or textile sheet.interwoven.

[0012] According to the invention, at least some of the warp threads are elongated fiber profiles, each formed from an elongated fiber material and a matrix material that impregnates the fiber material and completely consolidates it. The warp threads are therefore largely rigid.

[0013] Due to the fact that the warp threads of the inventive semi-finished fabric are fully cured fiber-reinforced plastic composite threads or fiber-reinforced plastic profiles, the warp thread alignment results in optimal flexural and torsional stiffening of the textile fabric, significantly simplifying the handling of such semi-finished fabrics in the manufacture of fiber-reinforced composite components. Furthermore, it has been shown that the use of cured fiber-reinforced plastic composite threads as warp threads can significantly reduce the risk of delamination within multilayer fiber laminates.

[0014] Furthermore, it has surprisingly been shown that such elongated fiber profiles containing a fully consolidated matrix material can be used as warp threads within a weaving process without this having a negative impact on the weaving quality of the semi-finished fabric.

[0015] According to an advantageous embodiment, at least some of the weft threads are formed from an elongated fiber material without an impregnating and fully consolidated matrix material. The weft threads are therefore flexible.

[0016] According to one embodiment, it is provided that at least some of the weft threads are formed from glass fiber rovings or carbon fiber rovings as elongated fiber material.

[0017] According to one embodiment, it is provided that all weft threads of the semi-finished fabric have a common weft thread orientation of substantially 90° with respect to the reference orientation, which corresponds to a conventional biaxial weave or a conventional biaxial weave pattern.

[0018] Alternatively, the weft threads can also be divided into a first group of weft threads and a second group of weft threads, wherein the first group of weft threads has a first weft thread orientation, while the second group of weft threads has a second weft thread orientation different from the first weft thread orientation. Both the first weft thread orientation and the second weft thread orientation are different from the warp thread orientation. This makes it possible to provide a semi-finished fabric having a triaxial weave or a triaxial weave pattern.

[0019] Preferably, the first weft thread alignment of the first group of weft threads has an angle of substantially +45° relative to the reference alignment, while the second weft thread alignment of the second group of weft threads has an angle of substantially -45° relative to the reference alignment. The first weft thread alignment and the second weft thread alignment form an angle of 90° between them.

[0020] According to one embodiment, at least some of the warp threads are elongated, round fiber profiles. Such round fiber profiles are produced, for example, in a pultrusion process in which dry, elongated fiber material, such as rovings, is impregnated with a matrix material and then passed through a die. The matrix material is then cured or consolidated, resulting in a substantially rigid, round fiber profile.

[0021] According to one embodiment, the warp threads are made of glass fiber reinforced plastic (GRP) or carbon fiber reinforced plastic (CFRP).

[0022] The object is also achieved according to the invention with the fiber composite component according to claim 8, wherein the fiber composite component is made of a fiber composite material comprising a fiber material and a matrix material embedding the fiber material. According to the invention, the fiber composite component is formed at least partially from a semi-finished fabric as described above as the fiber material of the fiber composite material.

[0023] The object is also achieved according to the invention with a method for producing such a semi-finished fabric according to claim 9, in which warp threads are interwoven as the first thread system and weft threads as the second thread system. According to the invention, elongated fiber profiles are used as warp threads, each formed from an elongated fiber material and a matrix material that impregnates and completely consolidates the fiber material.

[0024] Advantageous embodiments of the method can be found in the corresponding subclaims.

[0025] The object is also achieved according to the invention with the method for producing a fiber composite component according to claim 15, wherein the fiber composite component is produced from a fiber composite material comprising a fiber material and a matrix material embedding the fiber material. According to the invention, it is also provided here that a semi-finished fabric as described above or produced as described above is used.

[0026] The invention is explained in more detail using the accompanying figure as an example. It shows: Fig. 1 Illustration of a triaxial fabric semi-finished product.

[0027] Fig. Figure 1 shows a triaxial fabric semi-finished product 10 having a first thread system in the form of warp threads 11 and a second thread system in the form of weft threads 12 and 13. The warp threads 11 and the weft threads 12 and 13 are interwoven.

[0028] The warp threads 11 are elongated, round fiber profiles, each formed from an elongated fiber material and a matrix material that impregnates the fiber material and is fully consolidated. This results in flexural rigidity in the warp thread direction as well as corresponding torsional rigidity.

[0029] The alignment of the warp threads forms a reference direction, in relation to which the weft threads are defined with regard to their direction. The warp thread alignment in the example of the Fig. 1 an angle of 0° and thus forms the reference.

[0030] A first group of weft threads 12 has a first weft thread direction, which has an angle of +45° (positive clockwise) with respect to the warp thread orientation. Furthermore, the semi-finished fabric 10 has a second group of weft threads 13, which have a second weft thread direction, which has an angle of -45° with respect to the warp thread orientation.

[0031] This results in a fabric semi-finished product 10 which has reinforcing fibers running in three different directions within the fabric plane, namely 0°, +45° and -45°. Reference symbol 10 semi-finished fabrics 11 warp threads 12 first group of weft threads 13 second group of weft threads

Claims

[1] Semi-finished fabric (10) which has at least two different thread systems and is formed from a plurality of warp threads (11) as a first thread system with a predetermined warp thread orientation and a plurality of weft threads (12, 13) as at least a second thread system with at least one weft thread orientation different from the warp thread orientation, wherein at least some of the warp threads (11) are elongated fiber profiles which are each formed from an elongated fiber material and a matrix material which impregnates the fiber material and is completely consolidated. [2] Semi-finished fabric (10) according to claim 1, characterized by that at least a part of the weft threads (12, 13) is formed from an elongated fiber material without impregnating and completely consolidated matrix material. [3] Semi-finished fabric (10) according to claim 1 or 2, characterized bythat at least a part of the weft threads (12, 13) is formed from glass fiber rovings or carbon fiber rovings as elongated fiber material. [4] Semi-finished fabric (10) according to one of the preceding claims, characterized by that all weft threads (12, 13) have a common weft thread orientation of substantially 90° or that a first group of weft threads (12) has a first weft thread orientation and a second group of weft threads (13) has a second weft thread orientation different from the first weft thread orientation. [5] Semi-finished fabric (10) according to claim 4, characterized by that the first weft thread orientation has an angle of substantially +45° and the second weft thread orientation has an angle of substantially -45°. [6] Semi-finished fabric (10) according to one of the preceding claims, characterized by that at least some of the warp threads (11) are elongated round fiber profiles. [7] Semi-finished fabric (10) according to one of the preceding claims, characterized by that the warp threads (11) are made of glass fiber reinforced plastic (GRP) or carbon fiber reinforced plastic (CFRP). [8] Fiber composite component made of a fiber composite material comprising a fiber material and a matrix material embedding the fiber material, characterized by that the fiber composite component is formed at least partially from a semi-finished fabric (10) according to one of claims 1 to 7 as fiber material of the fiber composite material. [9] Method for producing a semi-finished fabric (10) which has at least two different thread systems and is formed from a plurality of warp threads (11) as a first thread system with a predetermined warp thread orientation of 0° and a plurality of weft threads (12, 13) as at least a second thread system with at least one weft thread orientation different from the warp thread orientation, characterized by that elongated fiber profiles are used as warp threads (11), each formed from an elongated fiber material and a matrix material impregnating the fiber material and completely consolidating it. [10] Method according to claim 9, characterized by that for at least some of the weft threads (12, 13) an elongated fiber material without impregnating and completely consolidated matrix material is used. [11] Method according to claim 9 or 10, characterized by that glass fiber rovings or carbon fiber rovings are used as elongated fiber material for at least some of the weft threads (12, 13). [12] Method according to one of claims 9 to 11, characterized bythat the semi-finished fabric (10) is produced in such a way that all weft threads (12, 13) have a common weft thread orientation of substantially 90° or that a first group of weft threads (12) have a first weft thread orientation of substantially +45° and a second group of weft threads (13) have a second weft thread orientation of substantially -45°. [13] Method according to one of claims 9 to 12, characterized by that elongated round fibre profiles are used for at least some of the warp threads (11). [14] Method according to one of claims 9 to 13, characterized by that a glass fiber reinforced plastic (GRP) or a carbon fiber reinforced plastic (CFRP) is used for at least some of the warp threads (11). [15] Method for producing a fiber composite component from a fiber composite material comprising a fiber material and a matrix material embedding the fiber material, characterized bythat a semi-finished fabric (10) according to one of claims 1 to 7 or manufactured according to one of claims 9 to 14 is used as fiber material of the fiber composite material.

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