Method for manufacturing a composite component for articulation with other components

Abstract

The invention relates to a method for manufacturing a fiber preform for a component, the method comprising: - weaving a first core texture, the first core texture having an elongated shape extending in a longitudinal direction and comprising a central portion (10) in cross section, the central portion having two edges on opposite sides, each edge comprising two spread fiber portions (16a; 16b); - shaping the first texture, which at least involves spreading the spread portions to form a positioning surface (30) defined by the portions so spread and interwoven portions, the interwoven portions being located between these spread portions and which may be formed by extensions (18a) of the central portion; - positioning a second tape texture over the spread transverse portions and the interwoven fiber portions, the second texture forming a loop around the formed first texture to define a void space for articulation to another component.

Description

Technical Field

[0001] The present invention relates to a method for producing a preform of a composite component intended for articulation at its ends to other components, and to a method for producing such a component. Background Art

[0002] To reduce weight, it's often recommended to use composite materials instead of metal, a persistent concern in the particular case of aircraft components. In light of this, US Pat. No. 7,704,429 proposes manufacturing a landing gear strut made of composite material. This strut includes a so-called yoke region, which serves for articulation with other components and stress introduction. The region is formed from a laminated structure with interlayers of layers between the main layers, extending the bulk of the reinforcement. However, this solution has drawbacks. Compared to metal components, a laminated yoke results in an increase in the size of the stress introduction region to avoid the risk of delamination. Consequently, overall system weight reduction becomes less attractive, and component integration becomes more limited due to the increased volume. Another issue is that the proposed manufacturing technique involves significant manual intervention, which leads to inconsistencies and increased costs. Finally, the mechanical properties of the composite material proposed in this document could be improved, particularly in terms of compressive strength in a central region of the component's length, known as the common region. One option to address this issue is to add material to this common region, which is detrimental to quality and therefore not entirely satisfactory.

[0003] The present invention is intended to address all or part of the above-mentioned disadvantages. Summary of the Invention

[0004] The invention relates to a method for producing a fiber preform for a composite component to be articulated to other components, the method comprising at least:

[0005] - forming a first fiber core texture by weaving, the first fiber core texture having an elongated shape extending in the longitudinal direction and comprising, in cross section, a central portion having two positioning edges on opposite sides thereof, each positioning edge comprising two non-interconnected transverse fiber portions;

[0006] - forming a first fiber texture, which involves at least spreading the non-interconnected transverse portions to form a positioning surface defined by the transverse portions so spread and a portion of interwoven fibers situated between these spread portions, formed in extension of the central portion or by the central portion; and

[0007] - Positioning a second braided tape fiber texture over the expanded transverse portion and the interwoven fiber portion, the second texture forming a loop around the formed first texture so as to define a void space at the longitudinal ends between the first and second textures for articulation to other components.

[0008] The present invention proposes a solution based on an assembly between a core and a tape, each resulting from a braiding operation, with a tape positioning surface formed by an interwoven portion and a non-interconnected, unfolded portion flanking it. This solution provides an excellent interface for assembly, thereby ensuring good retention of the composite component and, in particular, allows for improvements in mechanical properties, particularly in terms of compressive strength, without compromising the quality of the structure, compared to US Pat. No. 7,704,429. Advantageously, the substantially planar positioning surface, resulting from the interwoven portion, avoids the need for third-party filler material between the unfolded portions. The non-interconnected portion allows for increased stiffness along all stress axes of the component after forming (optimization of inertia). The tape technology according to the present invention also allows for a more economical manufacturing cost than the prior art solutions discussed.

[0009] According to one example, each positioning edge further comprises an interwoven fiber texture extending the central portion and located between the non-interconnected transverse fiber portions, and the forming further comprises cutting the interwoven fiber texture to form the interwoven fiber portions.

[0010] According to this example, the interwoven portion is formed by a remaining fabric extension of the central portion within the positioning edge, which remaining fabric extension results from the cutting of the interwoven fiber texture.

[0011] According to one variant, the central portion comprises woven surface layers and non-woven yarn groups located between the woven surface layers and held together by yarns from the woven surface layers, the woven surface layers extending beyond the central portion into the positioning edges to form non-interconnected transverse fiber portions, and wherein, during forming, these non-interconnected portions are unfolded so as to fold them down to the height of the non-woven yarn groups.

[0012] According to this variant, the interwoven portion is formed by the central portion itself, at the same level as the unwound non-interconnected portion, and makes it possible to avoid having to perform the aforementioned cutting operation. Furthermore, the non-woven yarn groups form a stiffening portion that allows the compressive strength to be further increased compared to a structure obtained entirely by three-dimensional weaving.

[0013] In an exemplary embodiment, the non-interconnected transverse fiber portion is formed by weaving a first yarn and a second yarn, and has a first volume ratio of the first yarn relative to the second yarn; and the second texture is formed by weaving the first yarn and the second yarn, and has a second volume ratio of the first yarn relative to the second yarn, and the relative difference between the first volume ratio and the second volume ratio does not exceed 25%, for example, does not exceed 10%.

[0014] This feature helps to further increase the mechanical strength of the composite part to be obtained.

[0015] In one exemplary embodiment, the first texture and the second texture are made of carbon yarn.

[0016] The present invention also relates to a method for manufacturing a composite component for articulation with other components, the method comprising at least:

[0017] - forming a fiber preform for the component to be obtained by implementing the method described above; and

[0018] - A matrix is formed in the pores of the fiber preform thus obtained.

[0019] In one exemplary embodiment, the matrix is organic.

[0020] In an exemplary embodiment, the component is a landing gear strut, a section of a landing gear strut, or a brake rod. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] [ Figure 1 ] Figure 1 One example of a first fiber core texture that can be used in the context of the present invention is schematically shown.

[0022] [ Figure 2 ] Figure 2 Schematically shows the Figure 1 Cross-section of the first texture.

[0023] [ Figure 3A ] Figure 3A A first step of an example of forming a first texture according to the present invention is shown.

[0024] [ Figure 3B ] Figure 3B A second step of an example of forming a first texture according to the present invention is shown.

[0025] [ Figure 3C ] Figure 3C A third step of an example of forming a first texture according to the present invention is shown.

[0026] [ Figure 3D ] Figure 3D A fourth step of an example of forming a first texture according to the present invention is shown.

[0027] [ Figure 4 ] Figure 4 An example of a composite part preform obtained after positioning a second ribbon-like texture on a shaped first texture is schematically shown.

[0028] [ Figure 5 ] Figure 5 A cross section of a variant of a first texture that can be used in the context of the present invention is schematically shown.

[0029] [ Figure 6A ] Figure 6A Shown Figure 5 A possible first step in the shaping of the texture.

[0030] [ Figure 6B ] Figure 6B The second step of the forming is shown.

[0031] [ Figure 6C ] Figure 6C The third step of the forming is shown, consisting of the positioning of the tape on the formed texture. DETAILED DESCRIPTION

[0032] Figure 1 The diagram illustrates an example of a first fiber texture 1 that can be used in the context of the present invention. The first texture 1 has an elongated shape extending along a longitudinal direction X. As will be described below, it can be achieved in a single piece through three-dimensional weaving by providing non-interconnected regions. "Three-dimensional weaving" or "3D weaving" refers to a weaving method in which at least some of the first yarns oriented in the X direction are joined to second transverse yarns on several layers of second yarns. This weaving can be performed on a jacquard loom in a manner known per se. The first texture 1 is used to form the core of the fiber reinforcement of the resulting component. For example, a "cross rib" weave pattern can be used to form the first texture 1. The first texture 1 has longitudinal ends 3 with a curved shape (e.g., generally circular) and serves to define a void space in the resulting component specifically for articulation with other components. In the illustrated example, the longitudinal ends 3 are substantially identical in size, but those skilled in the art will recognize that other variations are possible, and in particular, the present invention can be applied to components having longitudinal ends of varying sizes.

[0033] The first texture 1 may be in the form of strips, and Figure 2A cross-section taken transverse to the longitudinal direction X is shown. The first texture 1 comprises a central portion 10 with two edges 12 on opposite sides 11 of the central portion, which serve to position the second texture and are referred to as positioning edges 12. The central portion 10 and the edges 12 each extend in the longitudinal direction X. The central portion 10 is located between the edges 12. In the example shown, the edges 12 and the central portion 10 are offset along the width (direction L) of the first texture. In the example shown, each positioning edge 12 comprises, sequentially along the thickness (direction E) of the first texture 1 (corresponding to its smallest dimension), a first non-interconnected transverse fiber portion 16a, a weaving fiber texture 18, and a second non-interconnected transverse fiber portion 16b. A first non-interconnected region 14a exists between the first portion 16a and the texture 18, and a second non-interconnected region 14b exists between the texture 18 and the second portion 16b. In the non-interconnected regions 14a, 14b, the yarn layers of the woven texture 18 and the yarn layers of the portions 16a, 16b between them are intentionally omitted to allow for the expansion of the portions 16a, 16b, as will be described below. The non-interconnected regions 14a, 14b originate from the side portion 11. Each of the portions 16a, 16b extends the central portion 10 beyond the side portion 11. In the illustrated example, the portions 16a, 16b and the interwoven texture 18, like the central portion 10, are achieved through three-dimensional weaving. However, this does not necessarily depart from the scope of the present invention; in particular, the interwoven texture can be formed from non-woven yarn layers (unidirectional yarn layers). It should be noted that the non-interconnected regions 14a, 14b can extend over the entire length or a portion of the length of the first texture 1, in particular, over at least 50% of the length LD of the first texture 1. In particular, the non-interconnected regions 14a, 14b can be present in the middle region ZM of the length of the first texture 1. The example considered relates to the case where the height of the non-interconnected areas 14a, 14b measured along the direction L does not vary along the longitudinal direction X, but in this case it does not depart from the scope of the invention, especially in the specific case where the longitudinal ends 3 have different dimensions. In particular, the height of the non-interconnected areas 14a, 14b can be varied so as to reach a maximum in the intermediate zone ZM, thereby further improving the quality of the interface with the belt and thus improving the mechanical properties of the common area, in particular the inertia of the core, thereby increasing the resistance to buckling under compressive loads or vibration modes. A possible structure of the first texture 1 has just been described, and now in combination Figures 3A to 3D The focus is on describing in detail its possible shaping in order to prepare for the positioning of the second belt texture.

[0034] like Figure 3AAs shown, the first texture 1 is positioned in a first tool 20, which includes two segments 22 for supporting the first texture 1. More specifically, the central portion 10 is held between the segments 22, and the segments 22 can optionally apply compacting pressure to the central portion 10 if the fiber rate needs to be adjusted. As shown, the two segments 22 can be offset along the direction E. The segment 22 has a face 22a and a curved surface 22b, and the face 22a can be essentially planar and supported on the central portion 10; the curved surface 22b extends from the face 22a in a direction opposite to the first texture 1. The face 22b defines an area 24 in particular near the positioning edge 12, and the non-interconnected parts 16a, 16b are used to cover the area 24 during cutting of the interwoven texture 18. Therefore, as shown Figure 3B As shown, the non-interconnected portions 16a, 16b are spaced apart from one another so as to be positioned on the region 24 of the respective segment 22, thereby releasing them from the interwoven texture 18. The non-interconnected portions 16a, 16b folded over the region 24 are retained in this region 24 by means known per se, for example by compression. Figure 3C As shown, the interwoven texture 18 is cut along the cutting line LD. This cutting can be carried out by water jet cutting, but those skilled in the art will recognize that other techniques are also possible. As shown, the cutting of the interwoven texture 18 can be carried out flush with the non-interconnected parts 16a, 16b held on the segment 22. In addition, the curved shape of the surface 22b ensures that the non-interconnected parts 16a, 16b extend away from the cutting line LD, thereby avoiding any risk of damage during this operation. The cutting residue of the texture 18 forms an interwoven portion 18a, which is located between the non-interconnected parts 16a, 16b and will serve as a supporting surface for the belt texture. Portion 18a is located in the fabric extension of the center portion 10. The fabric portion 18a can have a length short enough to have sufficient rigidity, thereby allowing it to maintain a straight shape along the direction L without any holding tool.

[0035] Once this cut has been made, the first texture is removed from the tool 20 and positioned between two forming bodies 23 of a second, different tool 21, this being the tool used to form the shape of the core of the part to be obtained. As shown, the forming bodies 23 can be offset along a direction E. Figure 3DSuch a forming is shown in which the non-interconnected portions 16a and 16b are spread out on the forming body 23 to form transverse fins and the first texture 13 so formed has an I-shaped cross section (called a bi-angular shape). In the example shown, each spread out non-interconnected portion 16a, 16b forms an elbow with the central portion 10, the angle of which is substantially equal to 90° with the direction L. The formed first texture 13 defines, on either side of the central portion 10, at the positioning edge 12, positioning surfaces 30 on which the second tape texture will be deposited. The positioning surfaces 30 are defined by the spread out non-interconnected portions 16a, 16b and by the interwoven portion 18a that extends the central portion 10 and allows filling of the material deficiency caused by the spread out non-interconnected portions 16a, 16b. This provides a good interface with the tape and in particular a positioning surface 30 of substantially planar shape, as Figure 3D The example just described uses two different tools, one for cutting and another for forming the first texture, but it would not depart from the scope of the invention if the same tool were used for both operations. Figure 4 As shown, the method continues by positioning a second braided tape fiber texture 40 around the first texture 13 formed by tool 21. The second texture 40 can have the form of a strip wrapped around the formed first texture 13. When the second texture 40 is positioned, it bears on the unwound portions 16a, 16b, but also on the interwoven portion 18a, which allows for a good interface between the two textures. The second texture 40 can be in the form of a single fabric strip, but it does not depart from the scope of the present invention if the second texture is in the form of several strips positioned end-to-end or side-by-side. The second texture 40 can also be achieved through three-dimensional weaving, for example, with an "interlock" pattern. The second texture 40 defines a closed loop around the formed first texture 13 and defines a void space 42 for articulation to other components. Inserts (not shown) can be temporarily used at the longitudinal ends 3, and the second texture 40 can be wrapped around these inserts to ensure the desired shape of the end region. As mentioned above, the volume ratios between the warp and weft yarns of each of the first texture 11 and the second texture 40 may be similar. These volume ratios correspond to the ratio: [volume occupied by warp yarns] / [volume occupied by weft yarns] for each considered texture.

[0036] A mating mold is then positioned around the assembly of the two textures 13 and 40 so as to define a cavity for introducing the matrix material with tool 21. The assembly is then densified, for example, by introducing a resin (such as an epoxy resin), which is then cross-linked if it is a thermosetting resin, or cooled if it is a thermoplastic resin. The matrix can be formed using a resin transfer molding technique, which corresponds to known techniques. This results in a composite component that is designed to be hinged to other components at its longitudinal ends. The fiber reinforcement of this component can be formed from carbon yarn, and the component can have an organic matrix as just described. This component may or may not be used in aerospace applications. For example, the component can be a connecting rod, a landing gear strut or its component, or a brake lever. During operation, the component can be designed to withstand primarily tensile and compressive forces. The resulting component can be mounted to the other component by positioning a hinge pin for connecting to the other component and a contact insert having the pin through the empty space 42.

[0037] The example just described relates to the case where the interwoven portion 18a is formed by a fabric extension of the central portion 10. However, the present invention also addresses the case where the central portion itself is located between the unfolded non-interconnected portions in order to provide a load-bearing surface for the second belt texture. Figure 5 and Figures 6A to 6C Let's discuss this example.

[0038] Figure 5is a cross-sectional view of a variation of a first texture 100 that includes a central portion 110 over its entire length or a portion thereof. The central portion 110 has two positioning edges 120 on opposite sides 111. Each positioning edge 120 includes non-interconnected lateral portions 160a, 160b separated by a non-interconnected region 140, thereby allowing these portions 160a, 160b to be spaced apart relative to each other. As in the previous example, the positioning edges 120 and the central portion 110 are offset along the width direction L, and the non-interconnected portions 160a, 160b are offset along the thickness direction E. The first texture 100 includes woven surface layers 102a, 102b, for example, obtained by three-dimensional weaving, which form a portion of the central portion 110 and extend in the extension of this portion to form the non-interconnected portions 160a, 160b. The skin layers 102a, 102b are formed by weaving together first yarns C1 to C4 and C13 to C16 extending in the longitudinal direction X and second yarns t1 to t8 extending in the direction L. It will generally be appreciated that the number of yarn layers and weaving patterns shown are provided as examples only and may be modified without departing from the scope of the present invention. The center portion 110 also includes a group 102c of non-woven yarns C5 to C12 positioned between the skin layers 102a, 102b and held together by yarns from the skin layers 102a, 102b. Note that yarn t4 extends in the first skin layer 102a outside the center portion 110 and is deflected so as to emerge from the first skin layer 102a to join the group 102c of yarns C5 to C12 in the center portion 110. Similarly, yarn t5 extends in a second skin 102b outside the core 110 and is deflected so as to emerge from this second skin 102b, thereby joining a group 102c of yarns C5 to C12 in the core 110 on the side opposite to yarn t4. Between the skins 102a, 102b, a package of non-woven yarns C5 to C12 102c is achieved, held in place by the deflected yarns t4 to t5. In the example shown, the core 110 is sequentially provided along the thickness direction E with: a first skin 102a, a non-woven yarn group 102c, and a second skin 102b. It should be noted that the non-woven yarn group 102c is present only in the core 110 and not in the positioning edge 120. It should also be noted that the yarns C5 to C12 may be non-woven only over a length of the first texture 100, for example, in the middle zone ZM thereof, but may be woven at the longitudinal ends of the first texture 100. The length over which the yarns C5 to C12 are non-woven may be greater than or equal to 50% of the length of the first texture 100. Figures 6A to 6C The diagram is simplified Figure 5With regard to the formation of the first texture and the positioning of the second tape texture 40, it will be understood that this configuration is symmetrical with respect to the directions L and E. In the example considered, the openings of the non-interconnected portions 160a, 160b are present on the forming body (not shown) so as to form an angle of substantially 90° with the direction L, and the non-interconnected portions 160a, 160b are positioned at the level of the non-woven yarn set 102c. This level is taken along the direction L. This provides a positioning surface 130 of generally planar shape, in which the non-interconnected portions 160a, 160b and the yarn set 102c of the central portion 110 located between them are at the same level, thus defining a support surface for the tape texture 40.

Claims

1. A method for producing a fiber preform for a composite component to be hinged to another component, the method comprising at least: - forming a first texture by weaving (1; 100), said first texture having an elongated shape extending in a longitudinal direction (X) and comprising, in cross section, a central portion (10; 110) having two positioning edges (12; 120) on opposite sides (11; 111), each positioning edge comprising two non-interconnected transverse fiber portions (16a; 16b; 160a; 160b), - forming said first texture, said forming said first texture involving at least spreading said non-interconnected transverse fiber portions to form a positioning surface (30; 130) defined by said non-interconnected transverse fiber portions so spread and by interwoven fiber portions, said interwoven fiber portions being located between said spread non-interconnected transverse fiber portions, being formed by extension of said central portion or by said central portion, and - Positioning a second texture (40) over the unfolded non-interconnected transverse fiber portion and the interwoven fiber portion, the second texture forming a loop around the formed first texture so as to define an empty space (42) at the longitudinal end between the first and second textures for articulation to other components.

2. The method according to claim 1, wherein Each positioning edge further comprises an interwoven fiber texture (18) extending the central portion and located between the non-interconnected transverse fiber portions, and wherein the forming further comprises cutting the interwoven fiber texture to form the interwoven fiber portions (18a).

3. The method according to claim 1, wherein The central portion comprises woven surface layers (102a; 102b) and a non-woven yarn group (102c), the non-woven yarn group being located between the woven surface layers and held together by yarns (t4; t5) from the woven surface layers, the woven surface layers extending beyond the central portion into the positioning edges to form the non-interconnected transverse fiber portions, and wherein these non-interconnected transverse fiber portions are unfolded so that they are folded down to the height of the non-woven yarn group during forming.

4. The method according to any one of claims 1 to 3, wherein The non-interconnected transverse fiber portion is formed by weaving a first yarn and a second yarn and has a first volume ratio of the first yarn relative to the second yarn; and wherein the second texture (40) is formed by weaving a first yarn and a second yarn and has a second volume ratio of the first yarn relative to the second yarn, and the relative difference between the first volume ratio and the second volume ratio does not exceed 25%.

5. The method according to claim 1, wherein The first texture (1; 100) and the second texture (40) are made of carbon yarn.

6. A method of manufacturing a composite component for articulation with another component, the method comprising at least: - forming a fiber preform for the component to be obtained by implementing the method according to any one of claims 1 to 5; as well as - A matrix is formed in the pores of the fiber preform thus obtained.

7. The method according to claim 6, wherein: The matrix is organic.

8. The method according to claim 6 or 7, wherein: The component is a landing gear strut, a section of a landing gear strut or a brake rod.

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