Device and method for producing a curved fiber preform from a bi-or multidirectional fiber semi-finished product

Abstract

A device for producing a curved fiber preform from a bi- or multidirectional fiber semi-finished product, in particular for an aircraft or spacecraft fuselage component has first lamellae and second lamellae formed to be couplable to one another criss-cross such that they are positioned on a shared plane and thus form a grid. The lamellae at least in part are formed resiliently bendable about an axis intersecting the shared plane such that a local orientation of the lamellae in the grid changes. An adhesion device or structure is formed for temporarily adhering the fiber semi-finished product and is configured such that the local fiber orientation of the fiber semi-finished product also changes accordingly when the lamellae bend.

Claims

1. A device for producing a curved fiber preform from a bi-directional or multidirectional fiber semi-finished product, the device comprising: a plurality of first lamellae; a plurality of second lamellae, which are coupled to the plurality of the first lamellae in a criss-cross pattern, such that the first and second lamellae are positioned on a shared plane and form a grid having a plurality of cells defined by intersections of the first and second lamellae, wherein the first and second lamellae at least in part are formed resiliently bendable about an axis intersecting the shared plane, such that a local orientation of the first and second lamellae in the grid is changeable; an adhesion structure, which is configured for temporarily adhering the fiber semi-finished product to the grid formed by the lamellae, such that a local fiber orientation of the fiber semi-finished product changes accordingly when the local orientation of the first and second lamellae in the grid change due to bending of the lamellae; and a neutral lamella, which is introduced into the grid at an angle that is different from an angle of orientation within the grid of the first lamellae and an angle of orientation within the grid of the second lamellae, wherein the neutral lamella is arranged in a region of a theoretical or actual neutral fiber of the curved fiber preform being produced, and wherein the neutral lamella is formed such that: a first portion of the cells of the grid, which are positioned on a first side of the neutral lamella, are stretched during bending of the first and second lamellae; a second portion of the cells of the grid, which are positioned on a second side of the neutral lamella, are compressed during bending of the first and second lamellae; and cells of the grid that are positioned directly on the neutral lamella are only insignificantly deformed.

2. The device of claim 1, wherein the first and second lamellae comprise corresponding plug sockets, which can be plugged into one another for coupling the first and second lamellae together to form the grid.

3. The device of claim 2, wherein corresponding plug sockets are combined and form a depth corresponding to a thickness of at least one of the first and second lamellae.

4. The device of claim 1, wherein: the curved fiber preform is for a fuselage component of an aircraft or spacecraft; and/or the first and second lamellae each comprise holes, which are formed through a thickness thereof and are positioned between points where the first and second lamellae intersect each other to form the cells of the grid, the holes being formed to fluidically interconnect the cells of the grid to allow for air circulation and/or pressure compensation between the cells of the grid.

5. The device of claim 1, wherein a deformable membrane provided as a support face for the fiber semi-finished product is provided on the grid.

6. The device of claim 5, wherein the deformable membrane is a resiliently biased membrane for compensating bending of the lamellae.

7. The device of claim 1, wherein the adhesion structure comprises an underpressure box, which fluidically contacts the grid and is configured to generate an underpressure in each cell of the grid.

8. The device of claim 7, wherein the underpressure can be applied by an underpressure connection, which is provided on the underpressure box and to which an underpressure source can be connected.

9. The device of claim 7, wherein the underpressure box comprises an upper face, which is perforated to form a perforation which is in a form of an arrangement of holes, wherein the upper face is in contact with a side of the grid that is opposite a side of the grid on which the adhesive coating is provided, such that the underpressure applied to the underpressure box can be transmitted into the grid, the device comprising: a sealing, which is formed as a covering and is applied over, so as to seal against, cells of the grid that are not covered by the fiber semi-finished product, holes of the upper face of the underpressure box that are not in contact with the grid, and in edge regions of the fiber semi-finished product, such that the underpressure is present substantially at the fiber semi-finished product.

10. The device of claim 9, wherein the perforation is provided in a first region, where the cells of the grid provided for supporting the fiber semi-finished product are located when the lamellae are detensioned, and in a second region, where the cells of the grid which are provided for supporting the fiber semi-finished product are located when the lamellae are bent.

11. The device of claim 9, wherein the sealing seals the perforation which is positioned alongside the cells of the grid which are provided for supporting the fiber semi-finished product in each state of the grid.

12. The device of claim 11, wherein the sealing has at least one of an air-impermeable local covering and selectively actuable valves of at least one of the perforation and the grid.

13. The device of claim 1, wherein the adhesion structure comprises: an adhesive coating formed on the lamellae, wherein the adhesive coating is configured to temporarily adhere the fiber semi-finished product to the grid formed by the lamellae, such that a local fiber orientation of the fiber semi-finished product changes accordingly when the local orientation of the lamellae in the grid change due to bending of the lamellae; and an underpressure box, which fluidically contacts the grid and is configured to generate an underpressure in each cell of the grid to suck the fiber semi-finished product onto the grid at the adhesive coating.

14. The device of claim 13, wherein the adhesion structure comprises at least one of an adhesive coating or rough, jagged, and/or needle portions in an application region of the grid.

15. The device of claim 14, wherein the application region of the grid is at an edge of the fiber semi-finished product.

16. The device of claim 1, wherein the adhesion structure has a contact face which contacts the fiber semi-finished product on a side opposite the grid, a coefficient of friction between the contact face and the fiber semi-finished product being configured to be less than a coefficient of friction between the grid and the semi-finished product.

17. The device of claim 1, wherein at least one of the grid and the adhesion structure are formed as part of an end effector for transporting the previously curved fiber preform when the lamellae are bent.

18. A method for producing a curved fiber preform, comprising: applying a bi-directional or multidirectional fiber semi-finished product to a grid, which is formed by coupling a plurality of first lamellae to a plurality of second lamellae in a criss-cross pattern, such that the first and second lamellae are positioned on a shared plane and define a plurality of cells within the grid by intersections of the first and second lamellae, wherein the fiber semi-finished product is oriented on the grid such that the bi- or multidirectional fibers of the fiber semi-finished product at least in part extend parallel to at least one of the lamellae; introducing a neutral lamella into the grid at an angle that is different from an angle of orientation within the grid of the first lamellae and an angle of orientation within the grid of the second lamellae, wherein the neutral lamella is arranged in a region of a theoretical or actual neutral fiber of the curved fiber preform being produced; temporarily adhering the fiber semi-finished product to the grid; and resiliently bending the first and second lamellae, at least in part, about an axis intersecting the shared plane to change a local orientation of the first and second lamellae in the grid, wherein a local fiber orientation of the fiber semi-finished product changes accordingly when the local orientation of the first and second lamellae in the grid change due to bending of the lamellae; wherein the neutral lamella is formed such that, during the resilient bending of the first and second lamellae, fibers positioned on the first side of the neutral lamella deform in accordance with a stretching of the cells of the grid positioned on the first side of the neutral lamella, fibers positioned on a second side of the neutral lamella deform in accordance with a compression of the cells of the grid positioned on the second side of the neutral lamella, and cells of the grid that are positioned directly on the neutral lamella are only insignificantly deformed.

19. The method of claim 18, wherein: the temporary adhesion is provided by mechanical pressure acting on the fiber semi-finished product or fluidic underpressure acting on the fiber semi-finished product; and/or the first and second lamellae each comprise holes, which are formed through a thickness thereof and are positioned between points where the first and second lamellae intersect each other to form the cells of the grid, the holes being formed to fluidically interconnect the cells of the grid to allow for air circulation and/or pressure compensation between the cells of the grid.

20. The method of claim 18, comprising transporting the curved fiber preform by at least one of the grid when the lamellae are bent and an adhesion structure used for adhesion is provided.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Hereinafter, the disclosure herein is described in greater detail by way of the embodiments set out in the schematic and example drawings, in which:

(2) FIG. 1 is a plan view of a portion of a device for producing a curved fiber preform;

(3) FIG. 2 is a perspective view of a device according to FIG. 1;

(4) FIG. 3 is a further perspective view of the device of FIG. 2;

(5) FIG. 4 is a perspective drawing of a portion of a device for producing a curved fiber preform in accordance with a further embodiment;

(6) FIG. 5 is a schematic cross-sectional drawing of the device of FIG. 4;

(7) FIG. 6 is a perspective view of the device of FIGS. 4 and 5 when detensioned;

(8) FIG. 7 shows the device of FIG. 6 when bent;

(9) FIG. 8 is a drawing of a step of applying a fiber preform to the grid for the device of FIG. 4 through 7;

(10) FIG. 9 is a detail of the edge of the fiber semi-finished product of FIG. 8 applied to the grid;

(11) FIG. 10 shows the fiber semi-finished product of FIGS. 8 and 9 with an edge covered with additional sealing;

(12) FIG. 11 is a schematic cross-sectional view of a device for producing a curved fiber preform in accordance with a further embodiment;

(13) FIG. 12 is a detail of a membrane applied to the grid of the device; and

(14) FIG. 13 is a schematic cross-sectional view of a device for producing a curved fiber preform in accordance with another further embodiment.

(15) The accompanying drawings are intended to convey an improved understanding of the embodiments of the disclosure herein. They illustrate embodiments and serve in conjunction with the description to explain principles and concepts of the disclosure herein. Other embodiments and many of the stated advantages may be derived from the drawings. The elements of the drawings are not necessarily shown to scale with one another.

(16) In the drawings, unless stated otherwise, like, functionally equivalent and identically acting elements, features and components are provided with like reference numerals.

DETAILED DESCRIPTION

(17) FIG. 1 is a plan view of a portion of a device 1 for producing a curved fiber preform when bent.

(18) This is a device 1 for producing a curved fiber preform from a bi- or multidirectional fiber semi-finished product (not shown here) for a fuselage component of an aircraft or spacecraft, for example a former portion.

(19) The device 1 comprises a plurality of first lamellae 2 and a plurality of second lamellae 3, which are configured to be pluggable into one another criss-cross in such a way that they are positioned on a shared plane and thus together form a grid 4. An axis 5, which intersects the shared plane of the grid 4 and about which the lamellae 2, 3 are resiliently bent, is further illustrated schematically. In this way, the local orientation of the lamellae 2, 3 deforms continuously, in such a way that the cells of the grid 4, which are square when detensioned, recognisably change to stretched or compressed rhombuses.

(20) A fiber semi-finished product 9, not shown here, can be adhered temporarily on the grid 4 by an adhesion device or structure 6, here formed by way of example as an adhesive coating of the lamellae. The adhesion device or structure 6 is configured in such a way that the local fiber orientation of the fiber semi-finished product also changes accordingly when the lamellae 2, 3 bend. A corresponding coefficient of friction is therefore provided between the grid and the adhesion device or structure 6.

(21) Purely by way of example, the adhesive coating shown here is an adhesive strip permitted for fiber materials. For example, the adhesive strip is formed to be thermally resistant.

(22) In further embodiments, however, the adhesion device or structure 6 may have additional elements and/or measures for adhering the fiber semi-finished product, which are discussed in greater detail in reference to the following embodiments. In this case, an adhesive strip permitted for fiber materials may also be provided as an anti-adhesive coating so as to reduce the friction and/or as a contact face so as to provide reliable contact.

(23) The deformation or shaping of the fiber semi-finished product 9 using a device 1 of this type is performed by a carrier, which comprises the grid 4 which is formed using the lamellae 2, 3 plugged into one another in the form of shearable bars plugged into one another. The bars may have the same orientation (for example ±45°) as the fiber orientation of at least some of the layers of the fiber semi-finished product 9 to be shaped. The fiber semi-finished product is therefore applied before the deformation in a fiber orientation corresponding to the orientation of the lamellae.

(24) If the grid together with the fiber semi-finished product adhering thereto is sheared by bending, the fiber semi-finished product is also sheared together. By stops, the maximum deformation/shearing of the grid 4 and thus also the desired curved shape, for example a required curvature of a former shape, can also be established.

(25) FIG. 2 is a perspective view of the device according to FIG. 1.

(26) This drawing likewise shows a bent state of the grid 4, which can be seen clearly here.

(27) Further, FIG. 2 shows plug sockets 7 of the first and second lamellae 2, 3, which combine to form a depth corresponding to a thickness of the first and/or second lamellae 2, 3. These are slits which extend transverse to the longitudinal direction of the lamellae and which extend from a longitudinal face in each case approximately as far as the centre of a lamella 2, 3. In this context, the plug sockets of the first and second lamellae are formed with opposite orientations in each case, in such a way that they can be plugged into one another. At the base of a slit, a detensioning hole is provided in each case.

(28) FIG. 3 is a further perspective view of a device according to FIGS. 1 and 2.

(29) The device can be seen to comprise a plurality of first and second lamellae 2, 3. These are oriented in a ±45° orientation. For example, the lamellae may each be a flexible bar. As the material, a wide range of bendable materials are suitable, such as high-grade steel, spring steel, glass-fiber-reinforced plastics material, carbon-fiber-reinforced plastics material, thermoplastics or the like. By way of example, in the embodiment shown over 100 lamellae, which are highly flexible, are plugged into one another. The resulting grid is planar on both sides.

(30) In the grid 4, a neutral lamella 8 in the form of an individual bar is introduced in a third direction, and has a 0° orientation. The neutral lamella 8 is likewise formed using plug sockets, the lamellae 2, 3 of the grid 4 likewise being formed with additional plug sockets for receiving the neutral lamella 8.

(31) The neutral lamella 8 defines a neutral fiber of the deformation, in other words a line along which no shear deformation takes place. This may apply equally to the deformation of the grid 4 and of the fiber semi-finished product 9. Cells of the grid 4 which are positioned on a first side of the neutral lamella 8 are thus stretched when the lamellae 2, 3 bend, whilst cells of the grid positioned on a second side of the neutral lamella 8 are compressed.

(32) The fiber semi-finished product 9 can be sucked onto the grid 4 when an underpressure is applied by holes or ducts in the grid. For this purpose, in this embodiment the cells formed by the lamellae 2, 3 are fluidically connected via additional holes arranged between the plug sockets so as to make air circulation or pressure compensation possible between the cells.

(33) FIG. 4 is a perspective drawing of a portion of a device for producing a curved fiber preform in accordance with a further embodiment. FIG. 5 is a schematic cross-sectional drawing of the device of FIG. 4.

(34) In this embodiment, the device 1 also has a grid 4 as explained in reference to FIGS. 1 through 3.

(35) However, the adhesion device or structure 6A of this embodiment additionally comprises a hollow box which is arranged under the grid and which is formed as an underpressure box 16. Sealing 13 for sealing regions without fiber semi-finished product support is further provided.

(36) For applying underpressure to the grid 4, a connection 12 to an underpressure source, for example for connecting a vacuum cleaner tube as shown in FIG. 4, is provided on a side face of the underpressure box 16.

(37) On the upper face of the underpressure box 16, a perforation 14 as shown in FIG. 5 is provided in the form of an arrangement of holes, through which an underpressure applied to the underpressure box 16 can be transmitted into the grid 4. Via cells which are not covered by the semi-finished product 9 and holes of the perforation 14 which are not in contact with the grid 4, sealing 13 formed as a covering are applied. Further additional sealing 13 is further provided on the edge of the fiber semi-finished product 9, for sealing lateral cells of the grid 4 which are not covered by the semi-finished product, and fixed to the grid 4 using suitable fixing structure or device 10.

(38) In this way, the fiber semi-finished product 9 placed on the grid 4 is sucked onto the grid 4, as is symbolised by the perpendicular thick arrows in FIG. 5, in such a way that static friction occurs between the fiber semi-finished product 9 and the lateral flanks of the lamellae 2, 3, and adhesion of the fiber semi-finished product 9 to the grid 4 thus occurs.

(39) FIG. 6 is a perspective view of the device 1 of FIGS. 4 and 5 when detensioned, whilst FIG. 7 is a perspective view of the device 1 when bent.

(40) As a result of the deformation of the grid during bending, the face covered by the grid 4 is also displaced on the underpressure box 16. Thus, there are holes of the perforation 14 of the underpressure box 16 which are only positioned below the grid 4 when detensioned as in FIG. 6 or at the start of the deformation, and which are positioned alongside the grid 4 when bent or at the end of the deformation. Conversely, there are also holes of the perforation which are positioned outside the grid 4 at the start of the deformation and are positioned under it at the end of the deformation.

(41) For sealing the holes positioned alongside the grid 4 in each case, the perforation 14 is also covered by the covering in regions positioned alongside the grid. Otherwise, holes positioned outside the grid 4 would suck up false air and reduce the suction force available for the fiber semi-finished product 9 positioned on the grid 4. The covering provided as sealing 13 is accordingly formed so as to be displaced together with the deformation of the grid 4, as is indicated in FIG. 5 by the horizontal smaller arrows.

(42) Since the shape and the lengths of the outer edges of the grid 4 change during bending, the covering is further formed flexibly, in this case for example in the form of a flexible film. Further, in this case the covering consists of or comprises for example a plurality of sub-pieces which are displaceable with respect to one another.

(43) FIG. 8 is a drawing of a step of applying a fiber preform 9 to the grid 4 in the device of FIGS. 4 to 6. FIG. 9 is a detail of the edge of the fiber semi-finished product of FIG. 8 applied to the grid 4.

(44) It can be seen that at the edge of the fiber semi-finished product there are cells of the grid 4 which are merely covered in part. For these regions, in the embodiment shown an additional sealing 13 is provided, which is shown in FIG. 10.

(45) FIG. 10 shows the fiber semi-finished product 9 of FIGS. 8 and 9 with an edge covered with additional sealing 13.

(46) The additional sealing 13 serve to prevent false air from being sucked up at the edge of the grid 4, in particular in the gap shown in FIG. 9 between the straight end of the fiber semi-finished product 9 and the jagged edge of the grid 4 to which underpressure is applied. This additional sealing 13 is likewise formed as a covering, but unlike the film of FIG. 4 is formed as a resilient plastics material mat in this case by way of example. The additional sealing 13 may be positioned at the edge of the grid 4, as shown here, or else also be positioned on further portions of the grid 4 in further embodiments. Accordingly, the additional sealing 13 may also be a flexible or multi-part covering.

(47) FIG. 11 is a schematic cross-sectional view of a device 1 for producing a curved fiber preform in accordance with a further embodiment.

(48) This embodiment differs from the embodiments described previously in relation to FIGS. 4 through 11 by way of an additional membrane 11, which is provided between the grid 4 and the fiber preforms 9.

(49) In this embodiment, which is based on suction by way of underpressure, the membrane 11 is formed air-permeable and deformable. It serves to brace the fiber semi-finished product in compressed regions of the grid, so as to prevent local swelling into grid gaps, in other words into cavities of the individual cells.

(50) FIG. 12 is a detail of an embodiment of a membrane 11 applied to the grid 4 of the device 1.

(51) In this case the membrane 11 is formed as a metal grid by way of example. The threads of the metal grid have an identical orientation to the lamellae 2, 3 of the grid 4.

(52) By the additional metal grid, the fiber semi-finished product 9 is braced from below in the grid gaps. Since the threads of the metal grid extend in the lamellae direction, the metal grid and thus also the lamellar grid 4 still remain deformable, however.

(53) In other embodiments, however, instead of a metal grid a rubber membrane, for example perforated or slitted, may be used. For example, this is biased in accordance with a predetermined curvature of the fiber preform to be produced, so as to compensate the deformation of the grid 4 without swellings. The rubber membrane would subsequently have to be tensioned onto the grid 4 in such a way that the deformation of the rubber membrane is defined by the grid and thus subsequently also corresponds to the deformation of the textile (in other words not to the natural deformation of rubber).

(54) In a further embodiment, instead of a membrane 11 of this type it is also conceivable to make the grid 4 itself narrower-mesh, in other words from much smaller lamellae, in such a way that the grid 4 has smaller cells or smaller gaps and the fiber semi-finished product 9 is thus better supported.

(55) FIG. 13 is a schematic cross-sectional view of a device 1 for producing a curved fiber preform in accordance with another further embodiment.

(56) The distinguishing adhesion device or structure 6B of this embodiment comprises a planar bed, which supports the grid, and has a contact face 15, which contacts the fiber semi-finished product 9 on a side opposite the grid 4.

(57) The contact face 15 is for example formed as a stamp which covers the size of the grid in both states, which is for example in the form of a solid body plate, and which has an anti-adhesive coating. In this way, a coefficient of friction between the contact face 15 and the fiber semi-finished product 9 is less than a coefficient of friction between the grid 4 and the fiber semi-finished product 9. When mechanical pressure, symbolised by vertical arrows in FIG. 13, is applied via the contact face 15, static friction is thus built up between the grid 4 and the fiber semi-finished product 9. The deformation under mechanical pressure applied using the stamp can therefore be performed in the same manner described in relation to the preceding embodiments with application of underpressure.

(58) Further, in this case a membrane 11 for supporting the fiber semi-finished product 9 on the grid 4 may optionally also be provided. For example, in this case an (optionally biased) rubber membrane is used, but this does not need to be perforated.

(59) By a device in accordance with one of the above-described embodiments, in particular fiber preforms for C profiles for formers can be produced, for example for producing 90° portions of a former. Accordingly, the produced fiber preform may subsequently be processed further to form the desired component, for example by cutting away edge regions, optionally by further shaping to form the subsequent component shape. For example, this may include collaring the flange of the C profile for a former portion.

(60) Although the disclosure herein has been described entirely by way of several embodiments in the above, it is not limited thereto, but can be modified in various ways.

(61) For example, a fiber semi-finished product may also be heated while positioned on the bent grid 4 so as to activate a binder which is located in the textile of the fiber semi-finished product and which fixes the deformation. In this case, after cooling, the curved fiber preform can subsequently be received by a conventional gripper and transported onwards and/or processed further.

(62) A further conceivable embodiment of the device in the context of the disclosure herein is a simultaneous formation of the device as an end effector. For this purpose, the device 1 is for example rotated together with the suction substructure of an adhesion device or structure 6A, in other words together with the underpressure box 16 and the sealing 13, after deformation together with the curved fiber preform. The fiber preform is subsequently transported onwards, for example directly positioned on a further component preform, by the end effector formed integrally with the device. Therefore, in this embodiment, the curved fiber preform may also only be heated once it is on the component preform, in such a way that the shape of the fiber preform is fixed simultaneously with fixing on the component preform. For example, the component preform may be in the form of already deposited but not yet connected further layers for the component which is to be produced.

(63) If elastomer or rubber membranes are used on the grid 4, either below or above the fiber semi-finished product 9, a further embodiment may involve applying this membrane biased only in part or in portions to the grid. As a result of the different deformation of the grid and of the material of the membrane, for example rubber, the grid 4 is prevented from shortening on the radially inner side in the longitudinal direction, for example on the inside of the bending in the direction of the inner flange of a former preform. The membrane is thus compressed and can buckle in the absence of bias. As a result of the membrane being biased, it instead always remains planar, in such a way that buckling is prevented and the fiber semi-finished product is always optimally supported.

(64) In one embodiment, the bias of the rubber membrane can be provided in such a way that on the inner side of the curvature the tension is at a maximum at the start of the deformation and is near-zero when the end state of the deformation is reached. On the outside of the curvature, the bias may accordingly be provided the other way around, in such a way that there it is near-zero at the start of the deformation and becomes a maximum when the end state of the deformation is achieved.

(65) In a further embodiment, however, the bias of the membrane may also be provided to be exactly as great on the outside as on the inside, in such a way that when the grid is non-deformed or relaxed it also remains straight in the absence of external forces.

(66) 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”, “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.