Method for manufacturing a fiber composite component

Abstract

A fiber composite component includes a composite including cured matrix material and a fiber material embedded therein. At least one partial area of the fiber composite component is provided with at least one thread, which undulates as it extends along a surface area of the composite, so that sections of the thread alternately run inside of the composite and outside of the composite. An adhesive arrangement for such fiber composite components is also disclosed. Finally, methods for manufacturing such a fiber composite component or for manufacturing such an adhesive arrangement are disclosed.

Claims

1. A method for manufacturing a fiber composite component comprising: a) providing a fiber material with a separating foil on a surface area; b) introducing at least one thread into at least one partial area of the fiber material, such that the thread undulates as the thread extends along the surface area of the fiber material, such that sections of the thread alternately run inside of the fiber material and outside of the fiber material; c) infiltrating the fiber material with a curable matrix material; d) curing the matrix material; and e) peeling away the separating foil from the fiber material, so that the thread loops are free of the matrix material.

2. The method of claim 1, wherein the at least one thread includes a plurality of several fibers.

3. The method of claim 1, wherein the thread sections running outside of the composite each have a length of at least 0.2 mm.

4. The method of claim 1, wherein the thread sections running outside of the composite each have a length of at least 0.4 mm.

5. The method of claim 1, wherein at least 20% of the at least one thread runs inside of the composite and/or at least 30% of the at least one thread runs outside of the composite.

6. The method of claim 1, wherein at least 30% of the at least one thread runs inside of the composite and/or at least 40% of the at least one thread runs outside of the composite.

7. The method of claim 1, wherein the thread sections running outside of the composite in the surface area of a partial area are provided with a density of at least 5,000/qm.

8. The method of claim 1, wherein the thread sections running outside of the composite in the surface area of a partial area are provided with a density of at least 10,000/qm.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The disclosure will be explained in more detail below based on exemplary embodiments with reference to the attached drawings. Shown on:

(2) FIG. 1 is a schematic view to illustrate how a thread is introduced into a fiber material (tufting),

(3) FIG. 2 is a view corresponding to FIG. 1 after attaching additional fiber material layers,

(4) FIG. 3 is a view corresponding to FIG. 2 after infiltrated with matrix material and curing the latter,

(5) FIG. 4 is a view corresponding to FIG. 3 while removing cured matrix material so as to expose thread loops,

(6) FIG. 5 is a schematic view to illustrate an adhesive arrangement comprising two fiber composite components manufactured according to FIGS. 1 to 4, which were bonded with each other with an adhesive layer, and

(7) FIG. 6 is a view corresponding to FIG. 5 to illustrate a tear stopper functionality of fiber loops embedded into the adhesive layer.

DETAILED DESCRIPTION

(8) FIGS. 1 to 4 schematically illustrate an exemplary embodiment of a method for manufacturing a fiber composite component 10.

(9) Evident from FIG. 5 is the finished fiber composite component 10, specifically in a usage situation where it is bonded with a second fiber composite component 10 manufactured in the same way by means of an adhesive layer 100 (adhesive arrangement 1).

(10) The fiber composite component 10 (see FIG. 5) conventionally comprises a composite 12 comprised of cured matrix material (e.g., here a thermally cured epoxy resin system) and fiber material 14 embedded herein.

(11) In the exemplary embodiment shown, the fiber material 14 consists of eight textile layers 14-1 to 14-8. Of course, this number of layers must only be construed as an example, and can vary widely in practice as a function of the application.

(12) In one characteristic of the fiber composite component 10, at least one thread 16 is provided in at least one partial area (the area adjacent to the adhesive layer 100 on FIG. 5) of the fiber composite component 10, which undulates as it extends along a surface area 18 of the composite 12 in such a way that sections of the thread 16 alternately run inside of the composite 12 and outside of the composite 12. On FIG. 5, the thread sections running inside of the composite 12 are labeled 16-1, and the thread sections running outside of the composite 12 are labeled 16-2.

(13) In the adhesive arrangement 1 on FIG. 5, the thread sections 16-2 running outside of the composite are advantageously embedded into the adhesive layer 100, so that the positively embedded thread sections 16-2 enhance the adhesion of the adhesive layer 100 relative to the surface area 18 in terms of the strength and reliability of the adhesive bond.

(14) With reference to FIGS. 1 to 4, the method for manufacturing the fiber composite component 10 can be described as follows:

(15) In a first step, a fiber material is provided. In the example shown (see FIG. 1), these are only the semi-finished textile layers 14-1 to 14-5, wherein this stack of fiber materials is provided with a separating foil 20, at least in the partial area that subsequently forms the surface area 18.

(16) In the example shown, the fiber material is a dry fiber material, i.e., one that does not yet contain any matrix material. Alternatively, however, one, several or all of the semi-finished textile layers 14-1 to 14-5 could also be provided as prepregs (which are then no longer to be infiltrated with matrix material as the process continues).

(17) In a second step, the at least one thread 16 is introduced into the provided fiber material 14-1 to 14-5, such that the thread 16 undulates while extending along the surface area 18, such that thread sections alternately run inside of the fiber material 14-1 to 14-5 and outside of the fiber material 14-1 to 14-5. The thread sections running inside and outside of the fiber material are again labeled 16-1 and 16-2 on FIG. 1 (corresponds to FIG. 5).

(18) The thread 16 is introduced just as when tufting, i.e., the thread 16 is passed through the fiber material by means of a needle 22 from a flat side of the fiber material 14-1 to 14-5 (from below on FIG. 1), wherein the needle 22 is guided (upwardly on FIG. 1) to a point where a thread loop 16-2 is formed when subsequently drawing back the needle 22. On FIG. 1, the needle 22 is then moved a bit toward the right, and the process of puncturing and again retracting the needle 22 to create the next thread loop 16-2 is repeated. As a result of this tufting process, the thread 16 can be used to generate the desired number of thread loops 16-2 in the respective partial area. As in the case when tufting loop piles (e.g., carpets), multiple needles (multi-needle) or a row of needles (which row extends orthogonally to the drawing plane on FIG. 1) can be used to simultaneously introduce a corresponding plurality of threads 16, wherein a corresponding plurality of thread loops 16-2 is formed with each stroke of the multiple needles.

(19) For the sake of simplicity, only one such thread 16 is depicted on the figures.

(20) As shown on FIG. 2, the tufted fiber material comprised of the semi-finished layers 14-1 to 14-5 is then enhanced on the lower side (facing away from thread loops 16-2) with the remaining semi-finished layers 14-6 to 14-8 still needed for the fiber composite component 10.

(21) In the example shown, the semi-finished layers 14-6 to 14-8 consist of dry fiber material, i.e., one that does not yet contain any matrix material. Alternatively, however, one, several or all of the semi-finished textile layers 14-6 to 14-8 attached on the side facing away from the thread loops 16-2 in this stage of the procedure can also be provided as prepregs (which are then no longer to be infiltrated with matrix material as the process continues).

(22) If the semi-finished layers 14-1 to 14-8 have not yet been infiltrated with matrix material in this situation, these semi-finished layers are then correspondingly infiltrated with curable matrix material (here an epoxy resin system, for example). This is preferably done in an infiltration and molding tool used for this purpose, of the kind sufficiently known from the area of fiber composite technology.

(23) In the exemplary embodiment shown, the fiber material still dry in the situation according to FIG. 2 along with the separating foil 20 is placed in a suitable infiltration and curing tool, and there infiltrated and thermally cured.

(24) As evident from FIG. 3, this takes place not just so as to infiltrate the semi-finished layers 14-1 to 14-8, but also to embed the thread loops 16-2 protruding on the upper side into the supplied matrix material. The matrix material layer that is created above the separating foil 20 and embeds the thread loops 16-2 is apparent on FIG. 3 and labeled 24.

(25) When curing the matrix material in the respective molding tool, the matrix material layer 24 is correspondingly also cured.

(26) This matrix material layer 24 located over the separating foil is later removed again, so as to thereby again expose the thread loops 16-2 on the surface area 18.

(27) FIG. 4 illustrates how the thread loops 16-2 are exposed using a UV laser 26, the UV laser beam 28 of which is guided (e.g., scanned) over the matrix material layer 24, thereby chipping the latter at the sites in question and removing the resin from the thread loops 16-2. In the example shown, the separating foil 20 through which the thread loops 16-2 had previously protruded is here simultaneously peeled away as illustrated on FIG. 4 (the separating foil has a relatively low adhesive power compared to the used matrix material, which facilitates its separation from the underlying matrix material).

(28) Within the course of the disclosure, various types of layers are possible for the described laser removal of the surface matrix material layer (e.g., see resin layer 24 on FIG. 4). When using a UV laser, the laser beam energy can be mainly absorbed in the matrix material, for example (e.g., given an epoxy resin system as the matrix material), as a result of which this material can be gently removed (e.g., evaporated). Alternatively or additionally, for example, an IR laser can be used, whose radiant energy is absorbed very intensively by the thread, e.g., when using carbon fibers for the threads. It is most often advantageous to again also remove the matrix material that got into the thread loops during the curing process and/or beforehand, e.g., as a result of capillary action, in order to make the loops as flexible as possible once more. The flexibility of the loops or the loops being free of matrix material can be advantageous, in that the adhesive can then penetrate into the thread loops better during the subsequent bonding process. The potentially used cover layer(s) can advantageously also serve to ensure that the base composite (e.g., laminate) is less influenced by the laser, and that matrix material (e.g., resin) is removed only from the thread loops, if possible.

(29) Once the thread loops 16-2 have thus been exposed again and the separating foil 20 has been removed, the fiber composite component 10 is complete.

(30) In particular plate-shaped or shell-shaped fiber composite components can be fabricated in this way, for example, and can later be bonded with one or more additional components (e.g., fiber composite components, but also other types of components). The thread loops protruding on the fiber composite component can here be adjusted to the respective adhesive arrangement and provided in one or several respectively correlated surface areas (for example, see surface area 18 exemplarily shown on the figures), so that these thread loops are advantageously embedded into the respective adhesive layer, so that an additional attachment of the surface area(s) to the respective adhesive layer(s) is hence realized.

(31) As already mentioned, FIG. 5 shows such an adhesive arrangement 1, in which two plate-shaped or shell-shaped components 10, 10 were bonded via the adhesive layer 100 at their overlapping edge areas depicted on FIG. 5, e.g., to form a larger, flat structure (e.g., the outer skin structure of an aircraft). The example according to FIG. 5 on the one hand involves the fiber composite component 10 already described with respect to its manufacture, as well as the fiber composite component 10 manufactured in the same way. The configuration of the second fiber composite component 10 corresponds to the configuration of the already described fiber composite component 10. The corresponding components of the second fiber composite component 10 are denoted with the same reference numbers on the figures, but appended with an apostrophe.

(32) In order to manufacture the adhesive arrangement 1 shown on FIG. 5, the two components 10, 10 are first fabricated in the manner already described, wherein the partial area(s) at which a respective surface area 18 or 18 with protruding thread loops 16-2 or 16-2 is to be created are provided being adjusted to the desired configuration of the adhesive arrangement 1.

(33) A suitable adhesive is then applied, for example to the respective surface areas 18, 18 of one of the components 10, 10, and the other component 10, 10 is correspondingly attached and, at least in the bonding area, pressed on, while the adhesive is set or (e.g., with thermal assistance) cured.

(34) When bonding the components 10, 10, the thread loops 16-2, 16-2 provided in the partial areas of the two components 10, 10 arranged correspondingly relative to each other advantageously protrude into the adhesive layer 100 from both sides, as illustrated on FIG. 5.

(35) In this downstream adhesive bonding process (structural or secondary bonding), the respective adhesive flows around the thread loops 16-2, 16-2, so that, in addition to the adhesion of the adhesive layer 100 toward the adjoining surface areas, a positive locking fit of the thread loops 16-2, 16-2 is built up in the surrounding matrix material after the adhesive has set or cured. Given an adhesive failure of the bond, this positive locking fit advantageously offers a certain residual strength, and hence a tear stopper function, as illustrated on FIG. 6.

(36) FIG. 6 depicts a situation in which the adhesion of the adhesive layer 100 to the component 10 has failed, but the thread loops 16-2 protruding from the component 10 into the adhesive layer 100 stop a tear from propagating.

(37) While at least one exemplary embodiment of the present invention(s) is disclosed herein, it should be understood that modifications, substitutions and alternatives may be apparent to one of ordinary skill in the art and can be made without departing from the scope of this disclosure. This disclosure is intended to cover any adaptations or variations of the exemplary embodiment(s). In addition, in this disclosure, the terms comprise or comprising do not exclude other elements or steps, the terms a or one do not exclude a plural number, and the term or means either or both. Furthermore, characteristics or steps which have been described may also be used in combination with other characteristics or steps and in any order unless the disclosure or context suggests otherwise. This disclosure hereby incorporates by reference the complete disclosure of any patent or application from which it claims benefit or priority.