WO2009049737A1

WO2009049737A1 - Method for the production of a parison from semifinished textile material for an annular profiled frame section made of fiber composite

Info

Publication number: WO2009049737A1
Application number: PCT/EP2008/007734
Authority: WO
Inventors: Brian Bautz; Jürgen FILSINGER
Original assignee: Eads Deutschland Gmbh
Priority date: 2007-10-12
Filing date: 2008-09-16
Publication date: 2009-04-23
Also published as: DE102007049347A1; DE102007049347B8; DE102007049347B4

Abstract

The invention relates to a method for producing a parison from semifinished textile material in order to produce an annular profiled frame section (10) comprising at least one radial flange (12, 14) from the cured semifinished material that is impregnated with a matrix material. In said method, the parison (34) is produced by winding the semifinished product, which is fed in the form of a strip (30), onto a core (32). Incisions (50, 52) are made into the strip (30) that is to be wound from a strip edge which is used for forming the radial flange (12, 14) on the profiled frame section.

Description

Process for the production of a preform made of textile semi-finished product for a ring-shaped frame profile made of fiber composite material

The present invention relates generally to the production of preforms from textile semi-finished products for the production of fiber composite components.

The use of fiber-reinforced components (fiber composite components) is particularly interesting because of their high specific strength (ratio of strength to weight) in many applications. A fiber composite material is a composite material which generally consists of two major components, namely a matrix and fibers embedded therein. By mutual interactions of these components, the material receives higher quality properties than either of the two components involved individually.

Whether a component can be economically produced in practice as a fiber composite component or not depends on a large number of factors. In addition to the required properties in terms of mechanical strength and weight of the component plays in particular the desired shape of the component or geometry a major role. In particular, for complicated or very specially shaped components an industrial production in fiber composite technology due to the associated effort is often out of the question.

One example of this is the use of window frames for commercial aircraft in series production. Such window frames are typically formed by an annular window frame profile which is milled from aluminum.

In the manufacture of a larger commercial aircraft on the order of about 100 such window frame profiles are needed. Due to the demanding specification in this application in terms of weight and Strength, these components are usually milled from a special aluminum alloy. This leads to a considerable expenditure of time and money.

The present inventors have recognized that the practical difficulty of producing such window frame profiles is due to their annularity in combination with the required profile cross-sections. These window frame profiles have, for example, an L-shaped or U-shaped profile cross-section with at least one radial cross-sectional section, which forms a radial flange on the window frame profile.

Against this background, it is an object of the present invention to provide a simple way of producing an annular, at least one radial flange having frame profile in fiber composite technology.

With a corresponding manufacturing method, the advantages of fiber composite components, for example, but by no means exclusively for window frame profiles of the type described above could be used.

The above object is achieved according to the invention by a method according to claim 1 and a frame profile according to claim 13. The dependent claims relate to advantageous developments of the invention.

According to the invention, a method for producing a preform made of textile semifinished product is provided for producing an annular frame profile having at least one radial flange from the semi-finished product impregnated with a matrix material and hardened, wherein the preform is produced by winding the semifinished product fed as strip onto a core will, and wherein the wound tape is cut from a band edge, which is provided for forming the radial flange on the frame profile.

The invention advantageously makes possible a comparatively cost-effective, in particular easily automatable production of annular frame structures in fiber composite technology, which are suitable for numerous applications.

Essential for the invention, on the one hand, is the use of a winding process to produce the preform for the annular frame profile. Such a winding process is simple and, in particular, inexpensive to implement and can be automated and to a certain extent provides "automatically" an annularity of the preform. On the other hand, the provision of special cuts of the semifinished product strip used for the winding process is essential for the invention. As will be more fully understood below, particularly in the description of exemplary embodiments, such cuts have particular significance with regard to the formation of the (at least one) radial flange on a curved and / or angled portion of the frame profile. In some cases, these cuts enable the formation of the required radial flanges on the finished profile component.

In one embodiment it is provided that the band contains fibers in different orientations. This can be achieved for many applications, particularly advantageous strength properties of the frame profile. In this case, both identical and different proportions of fibers can be provided in different orientations. The proportions of fibers in different orientations can be selected in particular adapted to the requirements of the particular application. In an embodiment, it is provided that the band is a multiaxial fabric, a fabric or a braid. Thus, in particular a semifinished product strip of the aforementioned type (with several different fiber orientations) can be provided in a simple manner.

In an embodiment it is provided that the band contains fibers in 0 ° orientation. The "0 ° orientation" is intended here to mean that the respective fibers are oriented in the circumferential direction (based on the annularity of the preform or the frame profile to be produced therewith). In a particularly preferred development of this embodiment, the band contains fibers oriented in 0 °, which completely revolve (at least once) in the finished frame profile, i. H. are not interrupted in the ring.

Alternatively or in addition to the OΛOrientierung z. For example, it may be provided that the band contains fibers in 45 ° orientation and / or 90 ° orientation. In a specific embodiment, for example, it is provided that the band contains fiber orientations in 0 °, 90 ° and +/- 45 °.

In one embodiment, it is provided that the band represents a so-called "pre-preg" (preimpregnated fiber material). Such prepregs are known per se in various embodiments and therefore need no further explanation. In the context of the present invention, particularly advantageously usable prepregs z. B. contain continuous fibers which are embedded in an uncured thermosetting plastic matrix. Such prepregs are mostly commercially available wound on rolls commercially available and can, for. As a unidirectional or Mulitdirektionale layer, as tissue or scrim be present.

In principle, the production method according to the invention is suitable for any fibrous materials and matrix materials. As fibers come for example Glass fibers, carbon fibers, synthetic plastic fibers, steel fibers or natural fibers into consideration. As a matrix material, in particular plastics such. As thermosetting plastics (resins) interesting. In a specific embodiment, it is provided that the method according to the invention produces a preform which is used to produce an annular frame profile made of CFRP.

The term "annular frame profile" is to be understood in the context of the invention very broad and is intended to include each at least partially curved and / or angled running, total annularly extending element. In particular, such a frame profile over the entire circumferential course may be curved more or less, for example, to form a circular or oval frame profile. However, it should by no means be ruled out that one or more rectilinear portions are provided in the ring profile of the frame profile, such as for the formation of a polygonal frame profile, optionally with rounded polygon corners.

As such, the frame profile may form a frame to be manufactured (eg, window frames for an aerospace vehicle). Alternatively, the frame profile produced according to the invention, together with other elements, for. B. another such annular frame profile and / or other attachments, the frame to be produced.

Already profiles with L-shaped, Z-shaped or U-shaped profile cross-sections can be produced in a simple manner even with a single frame profile produced according to the invention. With regard to production of the preform close to the final contour, it is preferred if the core used in the winding process already has a shape configuration adapted to the desired profile cross section. In a preferred embodiment it is provided that the core is wrapped several times with the supplied tape. In particular in combination with the use of circulating, uninterrupted fibers in 0 ° orientation, a particularly high tensile strength of the finished component in the circumferential direction can thus be achieved.

In an embodiment it is provided that the strip is fed as a quasi-endless strip whose length is sufficiently dimensioned for producing a plurality of preforms. This measure is particularly interesting for a series production of preforms, for example for the production of identical preforms (eg more than ten), for example when it comes to the series production of corresponding frame profiles.

In one embodiment, it is provided that in the case of the formation of a radially inwardly or outwardly directed flange of the respective band edge with "simple cuts" (slots) is provided. In the case of the formation of a radially inwardly directed flange, alternatively or additionally, essentially V-shaped cuts (tapered towards the center of the strip) may be provided on the respective strip edge, which has the advantage that there is an overlap of the strip sections adjacent to the cuts on the annular strip Preform is reduced or completely avoided.

Regardless of the specific design of the incisions, it is provided in one embodiment that the incisions or center lines of the incisions each extend substantially orthogonally to the relevant band edge.

It is clear that at the points of the incisions each result in a certain material weakening. To thereby the strength of the finished frame profile not to significantly affect, is provided according to an advantageous embodiment, that the locations at which the tape to be wound is cut, are selected such that the incisions of adjacent winding layers are circumferentially offset zueinan- arranged on the wound tape. If the incisions are arranged equidistantly viewed at an edge of the supplied tape in the feed direction, the mutual distance of the incisions z. B. be sized so that a circumferential length of the wound on the core band is not an integer multiple of this distance. Depending on the desired shape design of the produced annular frame profile, this geometric condition can usually be realized in many ways. In an embodiment in which the incisions are arranged equidistantly on a band edge, z. Example, be provided that each incision on the wound strip viewed in the circumferential direction is at least approximately in the middle between two circumferentially adjacent incisions of an underlying (or overlying) winding layer of the tape. Here is an example: a mutual distance equidistant incisions amounts to 5 cm with a circumferential length of 102 cm. This is a favorable dimensioning (circumference = 20.4 x distance). On the contrary, when the mutual distance is 5 cm at a circumferential length of 100 cm, it is unfavorable (circumference = 20.0 x pitch).

Of course, the mutual distances of adjacent incisions can be adapted to a particular band edge of the relevant shape design or dimensioning of the relevant core, preferably taking into account the gradually increasing during the winding process peripheral length. The cuts do not have to be arranged equidistantly.

A preferred use of the method according to the invention is the production of a preform for producing a window frame element for an airframe. or spacecraft. Advantageously, low-cost semi-finished products (eg, multiaxial covers, woven fabrics, braids etc. in the form of straight strips) can be used with the invention and processed in a simple, automatable process for forming the preform. If the semifinished product strip used contains endless fibers in the 0 ° orientation, continuous fibers (apart from the beginning and the end of the strip) can be realized in a simple manner at least in one web region of the frame profile in the circumferential direction. For example, preforms may be made for annular CFRP frames or frame members having L, Z or U profile cross sections, e.g. For example, window frames or window frame elements for aircraft, in particular commercial aircraft.

The invention will be described in more detail by means of embodiments with reference to the accompanying drawings. They show:

Fig. 1 is a plan view of an annular frame profile for enclosing a window for a commercial aircraft,

Fig. 2 is a sectional view taken along line H-II in Fig. 1 and illustrating a Z-shaped profile cross-section of the annular frame profile of Fig. 1,

FIG. 3 is an illustration for illustrating a winding process for producing an annular preform from which the frame profile of FIG. 1 is manufactured; FIG.

4 to 7 are the corresponding sectional views of FIG. 2 for modified embodiments of frame profiles, Fig. 8 is a sectional view illustrating a profile cross section in an annular frame member which is composed of two annular frame profiles each having an L-shaped profile cross-section, and

Fig. 9 is a sectional view illustrating a profile cross section in an annular frame member composed of a Z-section frame profile and a L-section frame profile.

Fig. 1 shows a plan view of an annular closed, here as an oval frame profile 10 for enclosing a window for the passenger area of a commercial aircraft.

The frame profile 10 comprises two radial flanges, namely a radially inner flange 12 and a radially outer flange 14 interconnected by an axial web 16 (Figure 2).

Fig. 2 shows the total Z-shaped profile cross-section of the frame profile 10, which is composed in the illustrated embodiment by each rectangular profile regions of the two flanges 12, 14 and the connecting web 16.

The transition from the radially inner flange 12 to the axial web 16 and the transition from the radially outer flange 14 to the axial web 16 takes place at respective bends 18 and 20, respectively.

A method is explained below with reference to FIG. 3, by means of which, for example, the frame profile 10 shown in FIG. 1 in fiber composite technology, in particular z. B. can be produced as CFRP component. FIG. 3 illustrates how, by winding a textile semifinished product (here: a prepreg for producing a CFRP composite) fed onto a forming core 32, a preform 34 is produced by means of which a hardening process of a type known per se is produced (eg, thermally), the annular frame profile 10 (Figure 1) can be created.

The semifinished product strip 30 is withdrawn in the illustrated embodiment by a braked belt spool 36 in the direction of an arrow 38 or supplied to the rotationally driven core 32. The axis of rotation of the core 32 is indicated at 40. An arrow 42 symbolizes the direction of rotation.

The core 32 already gives the preform 34 produced by the winding process a shaping near the final contour by means of a corresponding contouring of the core 34 in the surface areas provided for supporting the tape roll. According to the frame profile 10 (FIG. 1), the preform 34 (FIG. 2) therefore likewise has a radially inner flange 44, a radially outer flange 46 and an axial web region 48 connecting these two radial flanges.

The semi-finished semi-finished product to be wound 30 is a flexible, but practically non-stretchable prepreg of pre-impregnated carbon fibers with different orientations (here: 0 °, 90 ° and +/- 45 °). Thus, the flanges 44 and 46, which are to be oriented on the preform 34 in the radial direction, can be easily formed, the tape 30 is cut at appropriate locations from the edge before it is wound on the core 32. An accomplishing this cutting or punching device can, for. B. be arranged in the course of the tape reel 36 to the core 32, but not shown in Fig. 3. When winding the band 30 on the correspondingly profiled outer circumference of the core 32, the radial flanges 44 and 46 of the preform 34 are formed by the The lateral edge regions of the band 30 are accordingly angled out of the axial plane of the central web region 48 out. For this shaping, suitable pressure rollers (not shown) are preferably used on the outer circumference of the core 32, which bring the supplied strip material into the desired profile shape during winding.

In the illustrated embodiment, that edge of the band 30 which is intended to form the radially inner flange 44 is provided with V-shaped cuts 50, which taper in the direction of the center of the band. In contrast, the other edge of the band 30, which is used to form the outer flange 46, is provided with "simple" (linear) cuts 52.

The V-shape of the cuts 50 is in this case dimensioned such that due to the curvature of the band 30 produced during winding, the V-shape "just closes", so that for the inner radial flange 40 an overlap of band areas resulting using simple incisions a winding layer is advantageously avoided.

In contrast to the inner flange 44, in the case of the outer flange 46, the corresponding recesses 52 are not "compressed" during the formation of the flange, but "spread apart", so that the curvature of the band 30 produced in the area of the outer flange 46 when the band 30 is wound up V-shaped recesses of the strip material arise. In a further development, it is conceivable to fill up these recesses resulting from the spreading by introducing correspondingly contoured semifinished product material, before a further material layer is wound up at this point. In the illustrated embodiment, the core 32 is wrapped some 10 times with the tape 30 for the production of the preform 34. The cuts 50 and 52 are in this case provided so that they are not arranged directly above one another after winding, but offset from each other. Another peculiarity of the illustrated embodiment is that the mutual incisions 50 and 52 are also offset from each other (viewed in the tape running direction 38, the incisions 50 are each in the space between two adjacent of the incisions 52).

Subsequent to the winding process illustrated in FIG. 3, the preform 34 thus formed is thermally cured, preferably in a molding tool. Depending on the semifinished product used (Volume 30), of course, other special manufacturing steps for the production of the final product (frame profile 10) can be used, as they are known per se from the fiber composite technology. For example, for certain semi-finished products, a prior infiltration of the matrix material before the curing process may be required.

In the following description of further embodiments, the same reference numerals are used for equivalent components, each supplemented by a small letter to distinguish the embodiment. In this case, essentially only the differences from the embodiment (s) already described are discussed and, moreover, reference is hereby explicitly made to the description of previous exemplary embodiments.

4 to 7 illustrate by way of example further design options with regard to the profile cross-section in a frame profile of the type shown in Fig. 1. Fig. 4 shows an L-shaped profile with a radially outwardly directed flange 14a.

Fig. 5 shows an L-shaped profile with a radially inwardly directed flange 12b.

Fig. 6 shows a U-shaped profile with two radially outwardly directed flanges 14c-1 and 14c-2, which are interconnected by an axial web 16c.

Fig. 7 shows a U-shaped profile with two radially inwardly directed flanges 12d-1 and 12d-2, which are interconnected by an axial web 16d.

The profiles according to FIGS. 4 to 7 can each be produced by a corresponding modification of the core used for winding as well as the cuts. For the profiles of Figs. 4 and 5, each comprising only a radial flange, it is sufficient to provide the winding process supplied to the Haizeugband only at a band edge with cuts.

FIGS. 8 and 9 illustrate that a frame profile element to be produced, for example a window frame of the type already explained above, can also be assembled from a plurality of annular frame profiles. The two figures each show the profile of a frame 60 composed of two frame profiles produced by the method described above (FIG. 8) and 62 (FIG. 9).

In summary, with the above embodiments of annular frame profiles components are created that are interesting due to the use of fiber composite technology "despite difficult geometry" for many applications.

Claims

claims

1. A method for producing a preform (34) from semifinished product, for producing an annular, at least one radial flange (12, 14) having frame profile (10) from the impregnated with a matrix material and cured semi-finished, wherein the preform (34) by winding of the semifinished product fed as a strip (30) is produced on a core.

2. The method of claim 2, wherein the wound tape is cut from a band edge, which is provided for forming the radial flange (12, 14) on the frame profile.

The method of claim 1 or 2, wherein the tape (30) contains fibers in different orientations.

A method according to any one of the preceding claims, wherein the band (30) is a multiaxial fabric, a woven fabric or a braid.

A method according to any one of the preceding claims, wherein the tape (30) contains fibers in 0 ° orientation.

A method according to any one of the preceding claims, wherein the tape (30) is a prepreg.

A method according to any one of the preceding claims, wherein the core (32) is wrapped several times with the tape (30) being fed.

8. The method according to any one of the preceding claims, wherein the tape (30) is fed as a quasi-endless belt (30), the length of which is sufficiently dimensioned for producing a plurality of preforms (34).

9. The method according to any one of the preceding claims, wherein in the case of forming a radially inwardly or outwardly directed flange (12 or 14) of the respective band edge with "simple cuts" (52) is provided.

10. The method according to any one of the preceding claims, wherein in the case of forming a radially inwardly directed flange (12) of the respective

Band edge is provided with substantially V-shaped cuts (50).

11. The method according to any one of the preceding claims, wherein the locations at which the tape to be wound is cut, are selected such that the incisions (50, 52) of adjacent winding layers are circumferentially offset from each other on the wound tape.

12. Use of a method according to one of claims 1 to 11 for producing a preform (34) for producing a window frame element (10), in particular a window frame element for an aircraft or spacecraft.

13. Frame profile (10), in particular window frame element, made of fiber composite material, produced by means of a preform produced according to one of claims 1 to 10 (34).

14. Frame profile (10) according to claim 13 for use as a window frame element for an aircraft or spacecraft.