FIBER COMPOSITE STRUCTURE AND METHOD FOR MANUFACTURING A FIBER COMPOSITE STRUCTURE

Abstract

A fiber composite structure includes a base structure being formed of a first fiber composite material that includes first fiber bundles embedded in a first matrix material, wherein the base structure includes an opening defined by first fiber bundles which include first sections and a second section that continuously or uninterruptedly interconnects the first sections, wherein the second section forms a bay that defines a part of the circumference of the opening. The fiber composite structure further includes a functional structure positioned in the opening of the base structure and joined with the first fiber composite material of the base structure.

Claims

1. A fiber composite structure, comprising: a base structure being formed of a first fiber composite material that includes a plurality of first fiber bundles embedded in a first matrix material, wherein the base structure comprises an opening defined by first fiber bundles which include first sections and a second section that continuously or uninterruptedly interconnects the first sections, wherein the second section forms a bay that defines a part of the circumference of the opening; and a functional structure positioned in the opening of the base structure and joined with the first fiber composite material of the base structure.

2. The fiber composite structure according to claim 1, wherein the bay has a form of an arc, a triangle, a rectangle, or a trapezoid.

3. The fiber composite structure according to claim 1, wherein the functional structure is formed of a second fiber composite material that includes a plurality of second fiber bundles embedded in a second matrix material, wherein the second fiber bundles are different from the first fiber bundles.

4. The fiber composite structure according to claim 3, wherein the second fiber bundles include quartz fibers, glass fibers, tellurite fibers, polymer fibers, or PMMA fibers.

5. The fiber composite structure according to claim 3, wherein, in a predefined frequency range, the second fiber composite material has a higher electromagnetic transmittance than the first fiber composite material.

6. The fiber composite structure according to claim 3, wherein end regions of the second fiber bundles are positioned between the first sections of the first fiber bundles.

7. The fiber composite structure according to claim 1, wherein the functional structure includes a solid body.

8. The fiber composite structure according to claim 7, wherein the functional structure includes a carrier frame defining an inner opening in which the solid body is fixed, wherein the carrier frame with an outer circumference is joined with the first fiber composite material of the base structure.

9. The fiber composite structure according to claim 8, wherein the carrier frame is a sleeve including, on a first end, a first rim or collar and/or, on a second end, a second rim or collar.

10. The fiber composite structure according to claim 7, wherein the solid body is made of a material that has, in a predefined frequency range, a higher electromagnetic transmittance than the first fiber composite material.

11. The fiber composite structure according to claim 7, wherein the solid body is made of glass or PMMA.

12. The fiber composite structure according to claim 1, wherein the first fiber bundles of the first composite material include carbon fibers or glass fibers.

13. A method for manufacturing a fiber composite structure, comprising: preparing a base structure by positioning a plurality of first fiber bundles such that at least some of first fiber bundles have first sections and a second section that continuously or uninterruptedly interconnects the first sections, wherein the second section forms a bay that defines a part of the circumference of an opening of the base structure; positioning a functional structure within the opening of the base structure; and joining the functional structure and the base structure by curing a first matrix material embedding the first fiber bundles.

14. The method of claim 13, wherein the first fiber bundles either are positioned as pre-preg tapes in which the first fiber bundles are pre-impregnated with the first matrix material or are positioned as dry first fiber bundles which are further infiltrated with a first matrix material before or after positioning of the functional structure.

15. The method of claim 13, wherein, in preparing the base structure, the first fiber bundles are laid down to extend substantially linearly and/or with generally constant spacing and, after being laid down, the fiber bundles, in the second sections, are moved to form the bay, or the first fiber bundles are laid down in a course that the first sections extend linearly and/or with generally constant spacing, and the second sections form the bay.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The disclosure herein will be explained in greater detail with reference to exemplary embodiments depicted in the drawings as appended.

[0027] The accompanying drawings are included to provide a further understanding of the disclosure herein and are incorporated in and constitute a part of this specification. The drawings illustrate the embodiments of the disclosure herein and together with the description serve to explain the principles of the disclosure herein. Other embodiments of the disclosure herein and many of the intended advantages of the disclosure herein will be readily appreciated as they become better understood by reference to the following detailed description. The elements of the drawings are not necessarily to scale relative to each other. Like reference numerals designate corresponding or similar parts.

[0028] FIG. 1 schematically illustrates a tank system comprising a fiber composite structure according to an embodiment of the disclosure herein.

[0029] FIG. 2 schematically illustrates a fiber composite structure according to an embodiment of the disclosure herein.

[0030] FIG. 3 schematically illustrates a cross-sectional view of fiber composite structure according to an embodiment of the disclosure herein in the region of an opening.

[0031] FIG. 4 schematically illustrates a cross-sectional view of fiber composite structure according to another embodiment of the disclosure herein in the region of the opening.

[0032] FIG. 5 schematically illustrates a further cross-sectional view of the fiber composite structure of FIG. 4; and

[0033] FIG. 6 schematically illustrates a flow diagram of a method for manufacturing a fiber composite structure according to an embodiment of the disclosure herein.

[0034] In the figures, like reference numerals denote like or functionally like components, unless indicated otherwise. Any directional terminology like “top”, “bottom”, “left”, “right”, “above”, “below”, “horizontal”, “vertical”, “back”, “front”, and similar terms are merely used for explanatory purposes and are not intended to delimit the embodiments to the specific arrangements as shown in the drawings.

DETAILED DESCRIPTION

[0035] FIG. 1 exemplarily shows a tank system 200 including a tank 205 and a sensor 210. The tank 205, as shown, may have a cylindrical shape or any other shape suitable to define an inner volume for storing gaseous or liquid fuel therein. For example, the tank 205 may be configured to store liquid hydrogen. Hydrogen, at a pressure in the range between 4 to 6 bar, is in a liquid state at temperatures of approximately −253° C. Of course, the tank 205 is not limited to this temperature and/or pressure range. For example, the tank 205 may be configured to withstand pressures up to 700 bar. Not only for storing liquid hydrogen but, generally, it is desirable that the tank 205 is reliably sealed and mechanically stable. Further, it would be advantageous to measure various physical quantities and/or states in the interior of the tank 205 without compromising mechanical stability or leak tightness.

[0036] The tank 205 shown in FIG. 1 may be formed of or comprise a fiber composite structure 100 that includes a base structure 1 and a functional structure 2 positioned and joined in an opening 10 of the base structure. In the specific example of FIG. 1, the functional structure 2 may be a window that is transparent for electromagnetic waves in a predefined frequency range. The sensor 210 may be arranged opposite the functional structure 2 and configured to measure a physical quantity, e.g. the temperature, and/or a filling level of the tank 205 by emitting waves through the window in the predefined frequency range.

[0037] The tank system 200 shown in FIG. 1 is one example for applying a fiber composite structure 100 of the disclosure herein. However, the disclosure herein is not limited thereto. The fiber composite structure 100 of the disclosure herein may be useful in various applications, such as antennas, radomes, and so on.

[0038] FIG. 2 schematically illustrates a fiber composite structure 100 including base structure 1 and a functional structure 2. Generally, the base structure 1 may comprise an areal expanse with a first surface 1a and an opposite second surface 1b. For example, the base structure 1 may be a plate, a shell, a skin or similar. The base structure 1 further includes an opening 10 which may, for example, be circular as exemplarily shown in FIG. 1. Alternatively, the opening 10 may be elliptical, rectangular, trapezoidal, triangular, or may have any other desired shape with a closed circumference. Generally, the opening 10 may extend between the first and the second surface 1a, 1b.

[0039] The base structure 1 is formed of a first fiber composite material that includes a plurality of first fiber bundles F1 embedded in a first matrix material X1. The first fiber bundles F1 may, for example, include carbon fibers or glass fibers. The first matrix material X1 may be a thermoplastics or thermoset resin. In more detail, the base structure 1 may be formed from a plurality of layers or sheets that are stacked over each other. Each layer includes a plurality of fiber bundles F1 and the first matrix material X1 forms a monolithic unit embedding the fiber bundles F1 of all layers.

[0040] FIGS. 3 and 4 both show schematic cross-sectional views of the fiber composite structure 100 when cutting the base structure 1 between adjacent layers or sheets. As shown in FIGS. 3 and 4, to define the opening 10 of the base structure 1, a spacing between adjacent first fiber bundles F1 is locally increased. In detail, the first fiber bundles F1 that define or delimit the opening 10 include two first sections 11 that may extend linearly or substantially linear and a second section 12 that interconnects the first sections 11. In particular, the second section 12 continuously or uninterruptedly interconnects the first sections 11. That is, one continuous, uninterrupted fiber bundle F1 includes as length portions arranged adjacent to each other the first section 11, the second section 12, and the further first section 11. As shown in FIGS. 3 and 4, the second section 12 extends so as to form a bay 13. The bay 13 defines or forms a part of the circumference of the opening 10. In FIGS. 3 and 4 it is exemplarily shown that the circumference of the opening 10 is defined by two mirrored bays 13 of generally semi-circular shape. Alternatively, only one bay 13 may be provided and the remaining circumference 10 may be defined by a linear extending section of a respective first fiber bundle F1. Without limiting the disclosure herein, the bay 13 may have the form of an arc, such as a semicircle or a segment of an ellipse, a triangle, a rectangle, or a trapezoid.

[0041] The course of the first fiber bundles F1 as described above by reference to FIGS. 3 and 4 may be present in at least some of the layers of the base structure 1, wherein it may be provided that the first sections 11 in neighbouring layers extend in different directions, in particular, in directions that run angled to each other, e.g. with an angle of 45 or 90 degrees.

[0042] As visible in FIGS. 3 and 4, the first fiber bundles F1 that define the opening 10 extend continuously around the void formed between the fiber bundles F1. Thereby, mechanical load or stress can be distributed over the areal expanse of the base structure 1 more uniform. Consequently, the mechanical strength of the base structure is increased.

[0043] The functional structure 2 is positioned in the opening 10 of the base structure 1 and joined with the first fiber composite material of the base structure 1.

[0044] As exemplarily shown in FIG. 3, the functional structure 2 may be formed of a second fiber composite material. The second fiber composite material may include a plurality of second fiber bundles F2 embedded in a second matrix material X2. The second fiber bundles F2, generally, are different from the first fiber bundles F1. For example, second fiber bundles F2 may include quartz fibers, glass fibers, tellurite fibers, polymer fibers, or PMMA fibers. The second matrix material X2, preferably, may be the same as the first matrix material X1, however, is not limited thereto. Optionally, the second fiber composite material, in a predefined frequency range, the second fiber composite material may have a higher electromagnetic transmittance than the first fiber composite material. For example, in the tank system 200 shown in FIG. 1, the second fiber composite material may have a transmittance of greater or equal than 0.4, preferably greater or equal than 0.5 for electromagnetic waves in the frequency range as emitted by the sensor 205.

[0045] Referring again to FIG. 3, it is shown that the second fiber bundles F2 extend through or span over the opening 10. In particular, the second fiber bundles F2 continuously extend between opposite end regions 20A, 20B. The end regions 20A, 20B of the second fiber bundles F2 may extend linearly and may be positioned between the first sections 11 of the first fiber bundles F1 as schematically shown in FIG. 3. As is further visible in FIG. 3 some of the second fiber bundles F2 may also have an intermediate portion 20C that generally follows or extends substantially parallel to the second portions 12 of the first fiber bundles F1. Other intermediate portions 20C extend linearly, too. It should be noted that the second fiber bundles F2 within one layer do not cross one another. Optionally, at least some of the second fiber bundles F2 may end between the first sections 11 of the first fiber bundles F1 at different locations with regard to the direction along which the preferably linear first sections 11 of the first fiber bundles F1 extend, as schematically shown in FIG. 3. As is further shown in FIG. 3, there may optionally be provided first fiber bundles F1′ that end adjacent to the ends of the second fiber bundles F2.

[0046] FIG. 4 exemplarily shows a fiber composite structure 100 that differs from that of FIG. 3 in that the functional structure 2 is not formed from a fiber composite material but includes a solid body 21. The solid body 21 may be realized as a cylinder, as exemplarily shown in FIG. 4. However, other shapes such as, for example, a block shape, a plate shape or similar, are possible of course. The solid body 21 may, for example, be a lens or another optical structure. Some examples of a material of which the solid body 21 is made include glass or PMMA. More generally, the solid body 21 may be made of a material that has, in a predefined frequency range, a higher electromagnetic transmittance than the first fiber composite material of the base structure 1.

[0047] As further shown in FIG. 4, the solid body 21 may optionally be held by a carrier frame 22. The carrier frame 22 may, for example, be realized as a sleeve as schematically shown in FIG. 5. Generally, the carrier frame 22 includes an inner opening 23 in which the solid body 21 is fixed. For example, the inner circumference of the opening 23 may correspond to the outer circumference of the solid body 21 which, in this case, is directly attached or joined with the carrier frame 22. Alternatively, the solid body 21 may be attached to an intermediate or inner frame which, in turn, with its outer circumference is fixed within the opening 23 of the frame 22, e.g. by welding or similar. The solid body 21 either alone or fixed within the carrier frame 22, as shown in FIG. 4, is located in the opening 10 of the base structure 1 and joined with the first matrix material X1. For example, an outer circumference 24 of the carrier frame 22 may be joined with the first matrix material X1. For example, in the tank system 200 shown in FIG. 1, the solid body 21 may have a transmittance of greater or equal than 0.4, preferably greater or equal than 0.5 for electromagnetic waves in the frequency range as emitted by the sensor 205.

[0048] FIG. 5 shows a cross-sectional view of the fiber composite structure 100 shown in FIG. 4. As exemplarily shown in FIG. 5, the carrier frame 22 may include, on a first end, a first rim or collar 22A and, on a second end, a second rim or collar 22B. Of course, it may be provided that only one of the first or second collars 22A, 22B is formed on the carrier frame 22. The collars 22A, 22B may be in contact with the surfaces 1a, 1b of the base structure 1 and, in particular, may be joined with the first matrix material X1.

[0049] FIG. 6 shows a flowchart of a method M for manufacturing a fiber composite structure 100. The method M, by way of example, will be explained by reference to the fiber composite structures 100 discussed above.

[0050] In step M1 the base structure 1 is prepared by positioning a plurality of first fiber bundles F1 such that a course of the fiber bundles F1 as shown in FIG. 3 or 4 is achieved. In detail, a plurality of fiber bundles F1 is placed such that at least some of first fiber bundles F1 have first sections 11 that preferably extend linear or substantially linear, and a second section 12 that continuously or uninterruptedly interconnects the first sections 11, wherein the second section 12 forms a bay 13 that defines a part of the circumference of the opening 10 of the base structure 1. In step M1, the first fiber bundles F1, for example, may be placed or laid down onto a surface of a tool by a fiber placement head.

[0051] According to one option, the first fiber bundles may be laid down in step M1 so as to extend generally constant spacing between them, that is, without the bay 13 being formed. After being laid down, the optionally linearly extending fiber bundles F1 in the second sections 12 may be moved away from each other so as to form the bay or bays 13 that define the opening 10. For example, a mandrel may be pushed through a gap between adjacent fiber bundles F1 to form the opening 10.

[0052] According to another option, the first fiber bundles F1, in step M1, may be laid down directly in a course that the first sections 11 extend with constant spacing and the second sections 12 form the bay 13.

[0053] In step M1, the first fiber bundles F1 may be positioned or laid down as pre-preg tapes in which the first fiber bundles F1 are pre-impregnated with the first matrix material X1. Alternatively, the fiber bundles F1 may also be placed as dry first fiber bundles F1.

[0054] In step M2, the functional structure 2 is positioned within the opening 10 of the base structure 1. Depending on the configuration of the functional structure 2, this may include placing the solid body 21 or the carrier frame 22 with the solid body 21 held therein into the opening 10 of the base body, or laying down the second fiber bundles F2 so that they traverse the opening 10, for example, as discussed above by reference to FIG. 3. The second fiber bundles F2 may be placed or laid down as pre-preg tapes in which the second fiber bundles F2 are pre-impregnated with the second matrix material X2. Alternatively, the second fiber bundles F2 may also be placed as dry second fiber bundles F2.

[0055] As discussed above, the second fiber bundles F2 or the solid body 21 may be placed or positioned after having formed the base structure 1 with the opening 10 therein. Alternatively, the disclosure herein also covers a method in which the second fiber bundles F2 or the solid body 21 may be placed or positioned first to form the functional structure 2 and, afterwards, the first fiber bundles F1 are laid down to form the base structure 1 in which the opening 10 is built around the functional structure. According to this alternative step M2 includes step M1.

[0056] In the case that the first fiber bundle F1 have been laid down as dry fiber bundles F1, a step of infiltrating the first fiber bundles F1 with the first matrix material M1 may be carried out, preferably after positioning M2 of the functional structure 2. In the case that the second fiber bundle F2 have been laid down as dry fiber bundles F2, a step of infiltrating the second fiber bundles F2 with the respective matrix material M2 may be carried out. Optionally, both, the first and the second fiber bundles F1, F2 may be laid down as dry fiber bundles which are infiltrated in a common infiltration step with the same matrix material.

[0057] In step M3, the functional structure 2 and the base structure 1 are joined by curing the first matrix material X1. Before joining, the first matrix material X1 and, if applicable, the second matrix material X2, too, are in an at least partially uncured state. By curing, e.g. by applying a predefined temperature treatment, the matrix material(s) X1, X2 form a uniform, monolithic block that embeds the first fiber bundles F1 and, if applicable, the second fiber bundles F2. In case that the functional structure 2 is a solid body 21, the first fiber material F1 may directly adhere to the solid body 21 or to the carrier frame 22 which, optionally, may be provided with a surface texture, e.g. in the form of grooves, ripples, roughness, or similar, to improve adhesion between the first matrix material X1 and the carrier frame 22.

[0058] One of the advantages of the fiber composite structures 100 discussed above is that they are able to withstand high mechanical loads although the base structure 1 is provided with an opening 10 in which the functional structure 2 is placed. In particular, the course of the first fiber bundles F1 with preferably linear first sections 11 and a bay section 12 is advantageous because the fiber bundles F1 are not interrupted by the opening 10 but continuously extend around or bypass the opening.

[0059] Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a variety of alternate and/or equivalent implementations may be substituted for the specific embodiments shown and described without departing from the scope of the disclosure herein as defined by the appended claims.

[0060] In the foregoing detailed description, various features are grouped together in one or more examples or examples with the purpose of streamlining the disclosure. It is to be understood that the above description is intended to be illustrative, and not restrictive. It is intended to cover all alternatives, modifications and equivalents. Many other examples will be apparent to one skilled in the art upon reviewing the above specification. In particular, the embodiments and configurations described for the seat modules and aircraft infrastructure can be applied accordingly to the aircraft or spacecraft according to the disclosure herein and the method according to the disclosure herein, and vice versa.

[0061] The embodiments were chosen and described in order to best explain the principles of the disclosure herein and its practical applications, to thereby enable others skilled in the art to best utilize the disclosure herein and various embodiments with various modifications as are suited to the particular use contemplated. In the appended claims and throughout the specification, the terms “including” and “in which” are used as the plain-English equivalents of the respective terms “comprising” and “wherein,” respectively.

[0062] While at least one example 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 example embodiment(s). In addition, in this disclosure, the terms “comprise” or “comprising” do not exclude other elements or steps, the terms “a”, “an” 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.

LIST OF REFERENCE SIGNS

[0063] 1 base structure [0064] 1a first surface [0065] 1b second surface [0066] 2 functional structure [0067] 10 opening [0068] 11 first sections [0069] 12 second section [0070] 13 bay [0071] 20A, B end regions of second fiber bundles [0072] 21 solid body [0073] 22 carrier frame [0074] 22A first rim or collar [0075] 22B second rim or collar [0076] 23 inner opening [0077] 24 outer circumference [0078] 100 fiber composite structure [0079] 200 tank system [0080] 205 tank [0081] 210 sensor [0082] F1 first fiber bundles [0083] F2 second fiber bundles [0084] M method [0085] M1-M3 method steps [0086] X1 first matrix material [0087] X2 second matrix material