Aviation housing preform comprising web having two deployable portions

Abstract

The invention relates to a web (500) extending between a proximal edge (103) and a distal edge (104), between a first side edge (103) and a second side edge (104) and between an inner surface (Fint) and an outer surface (Fext), said web comprising a distal portion (Pdist) located in the longitudinal direction between a middle portion (PI2) and the distal edge, the distal portion comprising, in its thickness direction, an inner portion (PDint) and an outer portion (PDext), the fibrous web is characterized in that the outer portion is connected to the inner portion by at least one connection portion (419), the outer portion comprising a first deployable portion separated from the inner portion by a first non-interconnected region (421) and a second deployable portion separated from the inner portion by a second non-interconnected region (422).

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a fibrous web which can be used, in particular but not exclusively, to form a fiber reinforcement of an aeroengine fan cowl made of a composite material. Background Art

[0002] The manufacture of a composite cowl begins with the production of a strip-shaped fibrous web which is made by three-dimensional weaving between multiple layers of warp yarns and multiple layers of weft yarns. The fibrous web thus obtained is wound around a mold or tool having the shape of the cowl to be produced for multiple turns and is held between the mold and a section forming a counter-mold to obtain a fiber preform.

[0003] Once the fiber preform is made, i.e., after the winding of the fibrous web is completed, the tool carrying the fiber preform is closed by the counter-mold and then transported to an oven or furnace where the preform is densified by a matrix which can be obtained, in particular, by injecting a resin into the fiber preform and polymerizing the resin.

[0004] The cowl must have a retention function to accommodate debris sucked into the engine or blades or blade fragments thrown out by centrifugal force to prevent them from completely passing through the cowl and releasing high-energy debris.

[0005] In addition, the turbine cowl is subject to relatively large vibration excitations. More specifically, the cowl houses blades which generate strong dynamic excitations due to tip impacts during operation. It is very important for the cowl to be able to cope with the dynamic excitations, especially to prevent the vibration natural modes of the cowl from being excited and causing an interaction between the rotor and the stator.

[0006] It must also be taken into account that the vibration stresses and the vibration natural modes of the cowl change as the turbine wears. For safety reasons, it is very important that the most energetic natural modes of the cowl are not excited at any time during the entire service life of the cowl.

[0007] To this end, strengthening regions can be provided to ensure that the cowl has sufficient mechanical strength.

[0008] However, when the cowl is made of a composite material, adding such strengthening regions requires connecting the material to the composite structure, which is not easily achieved using current methods.

[0009] Therefore, there is still a need to strengthen cowls having mechanical strength lower than that of prior art cowls and to obtain these cowls in a simpler manner than prior art cowls. Summary of the Invention

[0010] The present invention aims to solve the above problems.

[0011] To this end, the present invention relates to a fibrous web, which is strip-shaped and extends along a longitudinal direction between a proximal edge and a distal edge for a determined length, extends along a transverse direction between a first side edge and a second side edge for a determined width, and extends along a thickness between an inner surface and an outer surface.

[0012] The fibrous web has a three-dimensional or multi-layer braided structure between multi-layers of warp threads or strands extending along the longitudinal direction and multi-layers of weft threads or strands extending along the transverse direction, and the fibrous web includes a distal portion located between a middle portion and the distal edge in the longitudinal direction.

[0013] The distal portion includes an interior and an exterior in its thickness direction, and is arranged such that the interior extends between the inner surface and the exterior, and the exterior extends between the interior and the outer surface.

[0014] The fibrous web is characterized in that the exterior is connected to the interior by at least one connecting portion, the exterior includes a first deployable portion and a second deployable portion extending for a determined width along the transverse direction from the connecting portion, the first deployable portion is separated from the interior by a first non-interconnecting region, and the second deployable portion is separated from the interior by a second non-interconnecting region.

[0015] According to the fibrous web of the present invention, especially its two deployable portions, a preform of a cover can be formed, which includes a reinforcing member on the outer surface of the preform of the cover, and the preform of the cover can be directly formed from the fibrous web.

[0016] This enables a cover with improved mechanical properties with respect to vibration stress to be obtained, and any steps of adding a connecting reinforcing member during the manufacturing process of the cover are avoided.

[0017] Furthermore, the reinforcing member is better connected to the rest of the cover because it forms an integral part of the cover and does not require additional attachment or bonding. In this case, it is called an integral reinforcing member.

[0018] In one embodiment, the ratio of the thickness of the exterior to the thickness of the interior is between 150% and 260%.

[0019] In one embodiment, the ratio of the thickness of the exterior to the thickness of the interior is between 160% and 260%.

[0020] In one embodiment, the ratio of the distance from the first side edge to the connecting portion to the distance from the second side edge to the connecting portion is between 10% and 40%.

[0021] This embodiment can ensure that the reinforcement formed by the folding of the deployable part is located at a certain position on the fiber web and finally on the cover body, which enables an increase in the stiffness-to-mass ratio of the cover body, thereby increasing the natural frequency that can be obtained within the engine operating range.

[0022] In one embodiment, the connecting part is obtained by sewing the exterior onto the interior, by co-weaving the interior and the exterior, or by needling the exterior onto the interior.

[0023] The connecting part is essential for achieving a textile connection between the exterior and the interior. The connecting part exists between non-interconnected parts.

[0024] The various textile connection methods considered are all capable of achieving this connection, and each method offers different advantages.

[0025] Obtaining the connecting part by sewing enables the addition of the exterior as an extra thickness to the distal end of the rest of the fiber web.

[0026] This enables the very precise selection of the nature of the exterior and the very precise positioning of the connecting part and the non-interconnected areas.

[0027] Obtaining the connecting part by co-weaving can ensure a very firm attachment of the exterior to the interior. In addition, this enables the obtaining of the fiber web without additional steps, as the connecting part is directly formed during the weaving step of the fiber web.

[0028] Obtaining the connecting part by needling represents a connection step for the exterior that is less complex compared to the sewing step and also does not require modification of the weaving step compared to prior art methods.

[0029] In one embodiment, the distal end includes a plurality of connecting parts connecting the exterior and the interior.

[0030] In one embodiment, the distal end includes an upstream region, a middle region, and a downstream region in the width direction, and is arranged such that the upstream region extends between the first side edge and the middle region, the middle region extends between the upstream region and the downstream region, and the downstream region extends between the middle region and the second side edge, the middle region includes all the connecting parts, and wherein the middle region includes weft yarns and / or warp yarns having different properties from other yarns of the fiber web.

[0031] This embodiment enables the selection of yarns with different properties for the region of the fiber web intended to form the deployable part, thereby optimizing the specific performance of this characteristic region of the fiber web.

[0032] In one embodiment, the yarns outside the intermediate region have different properties, while the remaining yarns at the distal end are the same as the yarns of the rest of the fibrous web.

[0033] In one embodiment, the yarns of the fibrous web are selected from carbon fiber tows having an intermediate modulus (e.g., 300 GPa, such as HexTow IM7 type carbon fiber sold by HEXCEL), and wherein the intermediate region includes weft and / or warp yarns made of carbon fibers having a high modulus (450 GPa, such as HexTow HM63 type carbon fiber sold by HEXCEL). In this embodiment, the stiffness of the reinforcement is thus maximized. More specifically, since the stiffness of a beam is a function of Young's modulus, cross-sectional area, and length, increasing the modulus is equivalent to increasing the stiffness. This pushes the natural frequency towards higher frequencies, since it is a function of stiffness divided by mass and the mass remains constant.

[0034]

[0035] In one embodiment, the interior and exterior are non-interconnected over a distance of 90% to 98% of the width of the fibrous web.

[0036] This embodiment enables the obtaining of a deployable portion of sufficient length to ensure a further improved reinforcement function.

[0037] In one embodiment, the first deployable portion and the second deployable portion extend from the connecting portion in the transverse direction by a width of 1% to 5% of the width of the fibrous web.

[0038] The above is the description of the distal end of the fibrous web.

[0039] In one embodiment, additional properties can be imparted to the fibrous web by adjusting the proximal end of the fibrous web.

[0040] In one embodiment, the fibrous web includes a proximal end portion longitudinally located between the proximal edge and the intermediate portion.

[0041] The proximal end portion includes a proximal interior and a proximal exterior in its thickness direction, and is arranged such that the proximal interior extends between the inner surface and the proximal exterior, and the proximal exterior extends between the proximal interior and the outer surface.

[0041] Wherein, the proximal exterior is connected to the proximal interior by at least one proximal connecting portion, the proximal exterior includes a first proximal deployable portion and a second proximal deployable portion extending in the transverse direction from the proximal connecting portion by a determined width, the first proximal deployable portion is separated from the proximal interior by a first proximal non-interconnected region, and the second proximal deployable portion is separated from the proximal interior by a second proximal non-interconnected region.

[0042] The fibrous web according to the invention, in particular its two proximal deployable parts, can form a preform of the cover, which preform of the cover includes an attachment flange on the inner surface of the preform of the cover and can be formed directly by the preform of the cover.

[0043] This makes it possible to obtain a cover whose connection to other elements is greatly simplified compared to existing covers.

[0044] Therefore, the connection of the attachment flange to the rest of the cover is much better than the metal-composite attachment points of existing covers, because it is an integral part of the fibrous web of the cover.

[0045] In one embodiment, the ratio of the thickness of the proximal outside to the thickness of the proximal inside is between 50% and 170%.

[0046] In one embodiment, the ratio of the distance from the first side edge to the proximal connection part to the distance from the second side edge to the proximal connection part is between 10% and 30%.

[0047] This embodiment can ensure that the attachment flange formed by folding the proximal deployable part is located at a certain position on the fibrous web and ultimately on the cover, which makes it possible to attach other elements to the cover in a simplified manner.

[0048] In one embodiment, the proximal connection part is obtained by sewing the inside to the outside, by co-weaving the inside and the outside, or by needling the proximal inside onto the proximal outside.

[0049] The proximal connection part is essential for achieving a textile attachment between the proximal inside and the proximal outside. The proximal connection part exists between non-interconnected parts.

[0050] The various textile connection methods considered are all capable of achieving this attachment, and each method offers different advantages.

[0051] Obtaining the proximal connection part by sewing makes it possible to add the proximal inside as an extra thickness at the proximal end of the rest of the fibrous web.

[0052] This makes it possible to very precisely select the nature of the proximal outside and very precisely locate the proximal connection part and the proximal non-interconnected area.

[0053] Obtaining the proximal connection part by co-weaving can ensure a very firm attachment of the proximal inside to the proximal outside. In addition, this makes it possible to obtain the fibrous web without additional steps, because the proximal connection part is formed directly during the weaving step of the fibrous web.

[0054] Obtaining the proximal connection part by needling represents an internal connection step that is less complex compared to the suturing step and also does not require modifying the braiding step relative to the prior art methods.

[0055] In one embodiment, the proximal end portion includes a plurality of proximal connection parts that connect the proximal interior and the proximal exterior.

[0056] In one embodiment, the proximal end portion includes a proximal upstream region, a proximal middle region, and a proximal downstream region in the width direction, and is arranged such that the proximal upstream region extends between the first side edge and the proximal middle region, the proximal middle region extends between the proximal upstream region and the proximal downstream region, the proximal downstream region extends between the proximal middle region and the second side edge, the proximal middle region includes all the proximal connection parts, and wherein the proximal middle region includes weft yarns and / or warp yarns having different properties from the other yarns of the fibrous web.

[0057] This embodiment enables selecting yarns with different properties for the region intended to form the proximal deployable portion of the fibrous web, thereby optimizing the specific performance of this characteristic region of the fibrous web.

[0058] In one embodiment, the yarns in the proximal interior of the proximal middle region have different properties, while the remaining yarns of the proximal end portion are the same as the yarns of the rest of the fibrous web.

[0059] In one embodiment, the yarns of the fibrous web are selected from carbon fibers with a middle modulus of approximately 300 GPa, such as HewTow IM7 fibers sold by HEXCEL, and the proximal middle region includes weft yarns and / or warp yarns made of high modulus (approximately 450 GPa) carbon fibers, such as HewTow HM63 fibers sold by HEXCEL. In this embodiment, the stiffness of this region is maximized. By increasing the stiffness of this region and thus ultimately increasing the stiffness of the attachment flange, its mechanical strength is improved.

[0060]

[0061] In one embodiment, the proximal interior and exterior are non-interconnected at a distance of 95% to 99% of the width of the fibrous web.

[0062] This embodiment enables obtaining a proximal deployable portion with a sufficient length to form an attachment flange with the desired mechanical properties.

[0063] In one embodiment, the first and second proximal deployable portions extend in the transverse direction from the connection part with a width of 2% to 5% of the width of the fibrous web.

[0063] According to another aspect of the present invention, there is provided an aircraft cowling fiber preform, which comprises one or more turns of the fiber web as described above, the inner surface of the proximal edge of the fiber web is located on the radially inner surface side of the preform, and the outer surface of the distal edge of the fiber web is located on the radially outer surface side of the preform.

[0064] In one embodiment, the middle part of the fiber web is selected to correspond to the starting point of the last turn of the winding just described.

[0065] In this embodiment, the reinforcement formed by the deployable portion of the fiber web is present on the entire outer circumference of the cowling.

[0066] According to another aspect of the present invention, there is provided a method of manufacturing a composite aircraft cowling, which at least comprises the following steps:

[0067] - disposing the fiber preform as described above around a cylindrical core;

[0068] - disposing at least one mating mold on the radially outer portion of the fiber preform, the mating mold comprising at least one first mating mold part and at least one second mating mold part, and the deployable portion of the fiber web being located between the first mating mold part and the second mating mold part;

[0069] - forming a matrix in the fiber web held between the core and the mating mold.

[0070] In such an embodiment, the aircraft cowling is directly manufactured / formed with the reinforcement.

[0071] In other words, there is no need to attach the reinforcement to the cowling, and the reinforcement is directly formed in the fiber web during matrix formation, more specifically, in the deployable portion of the fiber web.

[0072] Furthermore, the mating mold comprises a geometry adapted to the deployable portion.

[0073] In an embodiment where the fiber web comprises a plurality of connecting portions, the mating mold may comprise more than two parts such that each reinforcement - i.e., the two deployable portions formed by one connecting portion - is present between two different mating mold parts.

[0074] These different mating mold parts enable easier demolding from the cowling once the matrix is formed.

[0075] In one embodiment, the matrix is organic, such as an epoxy resin, such as the PR520NRTM resin sold by Solvay S.A.

[0076] According to another aspect of the present invention, there is provided a composite gas turbine shroud, which comprises a fiber reinforcement formed from the fiber preform as described above and a matrix for densifying the fiber reinforcement.

[0077] Such an embodiment enables the reinforcement of the gas turbine shroud to be directly manufactured during the formation of the shroud, thereby improving the mechanical properties of the shroud without the need to add a reinforcement to the already formed shroud.

[0078] Therefore, the shroud according to the present invention is simpler to manufacture than the prior art shrouds, and the reinforcement is more reliably attached to the shroud.

[0079] According to another aspect of the present invention, there is provided an aero gas turbine engine comprising the shroud as described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0080] Figure 1 Schematically shows a loom that can be used to manufacture the fiber web according to the present invention.

[0081] Figure 2 [[ID=1S]]Shows the fiber web in an embodiment of the present invention.

[0082] Figure 3 Shows in the present invention Figure 2 Fiber webs of different embodiments.

[0083] Figure 4 Schematically shows a cross-sectional view of the fiber web in an embodiment of the present invention.

[0084] Figure 5 Schematically shows the deployment operation of the deployable portion of the fiber web according to an embodiment of the present invention.

[0085] Figure 6 Schematically shows Figure 2 The fiber web described in, in which the deployable portion has been deployed.

[0086] Figure 7 Schematically shows Figure 3 The fiber web described in, in which the deployable portion has been deployed.

[0087] Figure 8 Schematically shows obtaining a fiber shroud preform from the fiber web.

[0088] Figure 9 Shows Figure 8 A specific cross-sectional view of.

[0089] Figure 10 Schematically shows the laying of the fiber preform in an embodiment of the present invention, which is ready for impregnation.

[0090] Figure 11Schematically shows a turbine shroud according to an embodiment of the present invention.

[0091] Figure 12 Schematically shows a turbine according to an embodiment of the present invention.

[0092] Figure 13 Schematically shows a fibrous web according to an embodiment of the present invention.

[0093] Figure 14 Schematically shows a fibrous web according to an embodiment of the present invention. Detailed Description

[0094] The present invention will now be described with reference to the accompanying drawings, which are intended to illustrate certain embodiments of the present invention and should not be construed as limiting the present invention.

[0095] In particular, the drawings are not drawn to scale, or even to relative scale, and are only intended to illustrate the embodiments described below.

[0096] As Figure 1 shown, the fibrous web is woven in a known manner using a jacquard loom 5, on which bundles of warp threads or strands 20 are arranged in multiple layers and are connected by weft threads or strands 30.

[0097] In Figure 1 , the weft threads 30 are shown as extending in the transverse direction Y and the warp threads 20 are shown as extending in the longitudinal direction X.

[0098] However, it should be noted that the terms "weft thread" or "warp thread" are merely naming conventions, and throughout this and the rest of the present application, "weft thread" may be replaced with "warp thread" and vice versa.

[0099] Figure 2 Represents a fibrous web 500 in an embodiment of the present invention.

[0100] The fibrous web 500 is strip-shaped and extends a defined length L between a proximal edge 103 and a distal edge 104 in the longitudinal direction X 100 , a defined width l between a first side edge 101 and a second side edge 102 in the transverse direction Y 100 , and extends in the thickness Z between an inner surface F int and an outer surface F ext .

[0101] The fibrous web has a three-dimensional or multi-layer woven structure between multiple layers of warp threads or strands 20 extending in the longitudinal direction X and multiple layers of weft threads or strands 30 extending in the transverse direction Y. The fibrous web 500 includes a distal portion P located between an intermediate portion PI2 and a distal portion 104 dist . The distal portion P dist includes an interior PD in the direction of its thickness Zint and an external PD ext , arranged such that the internal PD int extends between the inner surface F int and the external PD ext , and the external PD ext extends between the internal PD int and the outer surface F ext . The fibrous web (sometimes also referred to as a web) 500 includes at least two non-interconnected regions 421, 422 located between the internal PD int and the external PD ext , and also includes a connecting portion 419 that connects the internal PD int to the external PD ext , so that the non-interconnected portions 441, 442 of the external PD ext form deployable portions of the fibrous web around the connecting portion 419.

[0102] In the illustrated embodiment, the intermediate portion PI2 starts from the starting point 460 of the distal end portion.

[0103] In one embodiment, the starting point 460 of the distal end portion may correspond to the starting point of the last turn of the shroud preform, as will be described in connection with Figure 10 .

[0104] For the sake of facilitating the description of the fibrous web 500, Figure 2 a fibrous web having only one connecting portion 419 is shown, but it should be understood that this embodiment does not limit the present invention.

[0105] The fibrous web 500 includes an upstream region 410, an intermediate region 420, and a downstream region 430 in the distal end portion P dist , and is arranged such that the upstream region 410 extends between the first side edge 101 and the intermediate region 420, the intermediate region 420 extends between the upstream region 410 and the downstream region 430, and the downstream region 430 extends between the intermediate region 420 and the second side edge 102.

[0106] For example, according to the required axial position of the reinforcement, the width l 410 of the upstream region 410 may be between 10% and 70% of the width l 100 of the fibrous web 500.

[0107] For example, according to the axial position of the reinforcement and the required height, the width l 420 of the intermediate region 420 may be between 2% and 10% of the width l 100 of the fibrous web 500.

[0108] For example, according to the required axial position of the reinforcement, the width l 430can be between 30% and 85% of the width l of the fibrous web 500 100 of the fibrous web 500

[0109] In one embodiment, as Figure 2 shown, the widths l 410 and l 430 may not be equal

[0110] The fibrous web 500 further includes an inner PD dist and an outer PD int in the distal end portion P ext which are located on one side of the inner surface F int and on one side of the outer surface F ext respectively, which enables the definition of Figure 2 six regions of the fibrous web visible in : an upstream inner 471, an upstream outer 444, an intermediate inner region, an intermediate outer region, a downstream inner 472 and a downstream outer 445

[0111] The intermediate region 420 itself is divided into smaller regions by a connecting portion 419 and two non-interconnecting regions 421, 422

[0112] Thus, the intermediate region 420 includes an inner portion 453 and two inner portions 451 and 452 which are connected to an outer portion 443 by the connecting portion 419, and the two inner portions 451 and 452 are not interconnected with the outer portions 441 and 442 located directly above and are separated from the outer portions 441 and 442 by the non-interconnecting regions 421, 422

[0113] In the case of a three-dimensional or multi-layer weave as described herein, when no weft or warp forms a textile connection between two non-interconnecting components, one component is said to be "non-interconnected" with the other, even if the two components were previously connected together. In other words, the non-interconnecting region is formed during the weave. Thus, the two components are said to be separated by the non-interconnecting region

[0114] In the present invention, generally, when there is no textile connection between two components, in other words, in the case where one of the two components is added after the weave, one component is also said to be "non-interconnected" with the other. If a part of the added component is connected to the other component in the connection region by, for example, needling, the remaining part of the added component (outside the connection region) will be said to be non-interconnected with the other component

[0115] Portion 451 is separated from portion 441 by non-interconnecting region 421, and portion 452 is separated from portion 442 by non-interconnecting region 422

[0116] In one embodiment, the non-interconnect region 421 may extend beyond the intermediate region 420, such as, for example, as Figure 2 shown, up to the first outer edge 101.

[0117] In one embodiment, the upstream interior 471 and the upstream exterior 444 are non-interconnected by a non-interconnect region 415 extending from the non-interconnect region 421.

[0118] In one embodiment, the non-interconnect region 422 may extend beyond the intermediate region 420, such as, for example, as Figure 2 shown, up to the second outer edge 102.

[0119] In one embodiment, the downstream interior 472 and the downstream exterior 445 are non-interconnected by a non-interconnect region 417 extending from the non-interconnect region 422.

[0120] In one embodiment, the non-interconnect regions 421 and 422 thus define deployable portions 442 and 441.

[0121] Figure 2 Also included is a frame IV corresponding to the cross-section to be shown in Figure 4 FIG.

[0122] In the Figure 2 embodiment described, the external PD ext is located within the thickness of the web, in other words, there is no thickness change in the web 500 at the starting point 460 of the distal end P dist .

[0123] In one embodiment, the thickness e of the exterior Dext may be between 60% and 72% of the total thickness e of the web 500 100 .

[0124] Figure 3 FIG. shows an alternative embodiment of the web 500.

[0125] Figure 3 Similar to Figure 2 , except that the internal PD dist at the distal end P int is an extension of the remainder of the web. In other words, the external PD ext is the excess thickness of the internal PD int , and the thickness of the internal PD int is equal to the thickness e of the remainder of the web 500 100 , in other words, the thickness of the internal PD int is equal to the thickness of the portion of the web extending between the proximal edge 103 and the point 460.

[0126] In this embodiment, the thickness e of the exteriorDext can be between 150% and 260% of the total thickness e of the fibrous web 500 100 .

[0127] In one embodiment, the thickness of the fibrous web 500 can vary gradually starting from the origin 460 of the distal end portion, for example varying over a length range of 15 cm on both sides of the point 460

[0128] In one embodiment, the external PD of the distal end portion ext is added to the internal PD of the distal end portion int .

[0129] For example, the external PD ext is added after the remainder of the fibrous web is formed and is attached to the internal PD through the connecting portion 419 int , for example by stitching or needling

[0130] This embodiment makes it possible to avoid any complex operations for creating non - interconnected regions during weaving, because in fact, if the external PD ext is attached to the fibrous web after the fibrous web is formed, then by definition, it is non - interconnected with the fibrous web except at the attachment points

[0131] In addition, this makes it possible to specifically select the fibers constituting the external PD ext , for example to have properties different from the remainder of the fibrous web, thus ensuring better mechanical properties, for example

[0132] Figure 4 In Figure 3 the cross - sectional view identified by box IV, the distal end portion P dist is shown in more detail

[0133] The distal end portion P dist includes the external PD Figure 4 identified in ext and the internal PD int . Between the two inner edges, there are also an upstream region 410, a middle region 420, and a downstream region 430

[0134] Figure 4 Also shown are an upstream inner 471, an upstream outer 444, middle inner regions (451, 452, and 453), middle outer regions (441, 442, and 443), a downstream inner 472, and a downstream outer 445

[0135] Figure 4 Also clearly shown are the warp yarns 20 and the weft yarns 602, 603, 606

[0136] In Figure 4In this case, the weft yarns are denoted by a plurality of numerical reference signs according to their configuration relative to the warp yarns 20.

[0137] In one embodiment, the internal PD int has its weft yarns 602 woven in a three-dimensional weaving manner with the warp yarns 20 of the internal PD int .

[0138] Here, the term "three-dimensional weaving" or "3D weaving" refers to a weaving method by which at least some of the warp yarns connect the weft yarns on multiple layers of weft yarns, such as "interlock weaving". The term "interlock weaving" refers to a type of three-dimensional weaving in which each layer of warp yarns combines multiple layers of weft yarns, and all the yarns in the same warp yarn column have the same movement in the weaving plane.

[0139] This particularly enables having the same weft yarn weaving as the rest of the fibrous web.

[0140] In one embodiment, as Figure 4 shown, the weft yarns 606 of the external PD ext may be non-connected in the upstream external 444 and the downstream external 445.

[0141] More specifically, since they are separated from the upstream internal 471 and the downstream internal 472 by the non-interconnect regions 415 and 417, and since they do not necessarily form part of the deployable portions 441 and 442, the yarns of the upstream external 444 and the downstream external 445 are intended to be cut and do not need to be woven.

[0142] For example, the incisions 501 and 502 may be formed at the boundaries of the intermediate region 420. The results of these incisions will be described in Figure 5 connection with Figure 5 what will present Figure 4 a detailed view of the box identified by the symbol V in

[0143] In one embodiment, the weft yarns of the portions 441, 442, and 443 of the external PD ext in the intermediate region 420 form a three-dimensional weave with the warp yarns.

[0144] This enables obtaining the deployable portions 441 and 442 with excellent performance and very good strength.

[0145] Furthermore, Figure 4 shows the weaving details in the intermediate region 420. In the illustrated embodiment, the regions 441, 442 are non-interconnected with the regions 451, 452 respectively, because the non-interconnect regions 421, 422 are continuous with the non-interconnect regions 415, 417 respectively.

[0146] More specifically, the weft yarns in the intermediate outer region 441 (or 442) are not connected to the warp yarns in the intermediate inner region 451 (or 452).

[0147] On the contrary, at the connection portion 419, the weft yarns in the intermediate outer region 443 are connected to the warp yarns in the intermediate inner region 453. The weaving 603 is schematically shown here, but it can be understood that the connection portion 419 is formed to terminate at the non-interconnecting regions 421 and 422.

[0148] Here, the connection portion 419 is shown as the yarn 603 passing through and co-weaving at the connection portion 419, but the specific effect of the connection portion 419 formed by the weft yarns of the part 443 and the warp yarns of the part 453 can be obtained by other textile methods, especially needling or stitching.

[0149] Combined Figure 5 with the description of

[0150] Figure 5 represents the intermediate region 420. More precisely, it shows the steps of unfolding the deployable portions 441 and 442.

[0151] Due to the non-interconnecting regions 421 and 422, the deployable portions 441 and 442 can be unfolded around the connection portion 419. Thus, a fibrous web with a more complex geometric shape than the initial fibrous web is formed.

[0152] Figure 5 Shows the deployable portions 441 and 442 after the formation of the incisions 501 and 502.

[0153] In one embodiment, the length of the deployable portion is selected according to the strengthening characteristics desired for the use of the fibrous web.

[0154] For example, if the fibrous web is intended to form a preform for an aircraft cowling, the length of the deployable portion can be between 1.8×π×R and 2.2×π×R, where R is the radius of the outer skin of the cowling.

[0155] In other words, the length of the deployable portion can be between 90% and 110% of the length of the outer skin of the cowling.

[0156] The incisions 501 and 502 thus mark the ends of the deployable portions 441 and 442. For example, the incisions 501 and 502 are formed along the entire length of the distal end P dist whose thickness corresponds to the thickness e of the outer part PD ext . Dext

[0157] In other embodiments, especially when there are more connection portions, the deployable portion can extend to the first inner edge 101 or the second inner edge 102 without the need for incisions.

[0158] However, other incisions can be formed in the intermediate region 420, between the two connecting portions, to form the deployable portions.

[0159] Figure 6 Represents the web obtained after performing the cutting and the deployment operations of the deployable portions 441 and 442.

[0160] Figure 6 More precisely corresponding to the web after all the forming operations of the deployable portions 441 and 442 Figure 2 in the web.

[0161] In particular, it will be noted that at the point 460 where the distal end portion P of the web dist starts, a thickness reduction 461 is observed.

[0162] More specifically, with respect to the initial web, i.e., Figure 2 the web, the upstream outer 444 and downstream outer 445 portions have been removed.

[0163] Since these portions contribute to the thickness of the distal end portion P of the web dist once the upstream outer 444 and downstream outer 445 are removed, the distal end portion P dist has a reduced thickness.

[0164] Thus, after the deployable portions are deployed, the distal end portion P dist only includes the interior PD consisting of the above-mentioned regions 471, 451, 453, 452, and 472 int .

[0165] In one embodiment, the deployable portions 441 and 442 together form a reinforcement 480.

[0166] The reinforcement 480 is held on the assembly of the remainder of the web by the connecting portion 419.

[0167] The remainder of the web is the same as above.

[0168] In Figure 7 the alternative embodiment shown, the reinforcement 480 can be formed such that the thickness of the web at the starting point 460 of the distal end portion P dist is not reduced.

[0169] In this case, the interior PD of the web int has a thickness similar to the remainder of the web, as in the embodiment shown for example Figure 3 where the outer PD ext is added to the interior PD int by stitching or needling.

[0170] In any case, the deployment of the deployable portions 441 and 442 can form the reinforcement 480.

[0171] Figure 8 The steps of disposing the web 500 as described above on the mold 50 to form a turbine shroud preform are shown.

[0172] The mold 50 can include a core 710 having the shape of the shroud to be formed.

[0173] Figure 8 The fiber shroud reinforcement formed by winding the above-described web 500 around the mold 50 is shown. This fiber reinforcement constitutes a complete tubular fiber preform of the shroud, forming a single piece. In particular, the laying of the distal end portion of the web 500 on the core 710 can be seen here.

[0174] The mold 50 includes a core 710 having an outer surface 51 whose profile corresponds to the inner surface of the shroud to be produced.

[0175] The inner surface F of the web 500 int is disposed on the outer surface 51 of the core 710, and then the web 500 is wound from its proximal edge 103 to its distal edge 104.

[0176] In Figure 8 , two arrows indicate the rotation of the core 710 required to form the web. Of course, the web can also be laid with the core fixed.

[0177] The core 710 also includes two rims 52 and 53 for forming the ends of the fiber preform corresponding to the flanges of the shroud, namely the downstream flange 62 and the upstream flange 63, respectively.

[0178] The portions of the fiber preform corresponding to the shroud flanges 62, 63 terminate at the second side edge 102 and the first side edge 101, respectively.

[0179] Figure 9 Indicates the cross-section of the web laid on the mold 50 shown by the box IX in Figure 8 .

[0180] The mold 50 includes a core 710 and also includes a first pair of mold parts 721 and a second pair of mold parts 722.

[0181] Figure 9 A specific case of a web having only one connection portion 419 and thus only one reinforcement 480 is shown, but it should be understood that webs including multiple connection portions and thus multiple reinforcements can be treated in a similar manner.

[0182] In Figure 9In the illustrated embodiment, the first pair of mold parts 721 can form a shroud part extending between the first side edge 101 and the stiffener 480, while the second pair of mold parts 722 can form a shroud part extending between the stiffener 480 and the second side edge 102.

[0183] Furthermore, dividing the mold into two parts 721, 722 ensures easy demolding from the mold without the risk of damaging the stiffener 480.

[0184] Figure 10 Another view shows the winding of the fibrous web 500 around the core 710.

[0185] The fibrous web 500 starts winding around the core from its proximal edge 103, and the inner surface F of the fibrous web int is disposed on the outer surface 51 of the core 710. The winding causes multiple turns of the fibrous web to be wound to form a preform until the laying of the distal end portion P dist as shown Figure 10 in the figure.

[0186] In the illustrated embodiment, the distal end portion P dist starts from point 460, which represents the starting point of the last turn of the fibrous web around the core 710.

[0187] This embodiment ensures that the stiffener 480 formed by the deployable portions 441, 442 of the distal end portion P of the fibrous web 500 dist exists on the entire last turn and ultimately on the entire circumference of the shroud.

[0188] In an alternative embodiment, it may be preferred to have the stiffener 480 only on a part of the shroud circumference. For this purpose, it is sufficient to set the point 460 closer to the distal edge 104.

[0189] Figure 10 The core 710 shown in the figure also has a counter mold 721 opposite thereto.

[0190] In this case, the counter mold 721 includes a plurality of counter mold segments (all labeled 721) and together form the counter mold 721 for the entire circumference of the core 710.

[0191] For example, once the fibrous web 500 is disposed on the core 710 to form a turbine shroud fibrous preform, the preform can then be densified by a matrix.

[0192] The densification of the fibrous preform includes filling the pores in all or part of the volume of the preform with a material constituting the matrix.

[0193] The matrix can be obtained according to liquid methods known per se. The liquid methods include impregnating a preform with a liquid composition containing an organic precursor of the matrix material. The organic precursor usually has the form of a polymer, such as a resin, optionally diluted in a solvent. The fiber preform is placed in a mold (the mold having a recess for molding the final part shape), and the mold can be closed in a sealed manner. As Figure 1 shown, here the fiber preform is placed between a plurality of sections 721 and 722 forming a pair of molds and a core 710 forming a support, and these elements respectively have the outer shape and the inner shape of the cover to be produced. Then, a matrix precursor liquid, such as resin, is injected into the entire recess to impregnate the preform.

[0194] The conversion of the precursor to the organic matrix, i.e., its polymerization, is carried out by heat treatment (usually by heating the mold). After removing all the solvents and crosslinking the polymer, the preform always remains in the mold and has the shape corresponding to the part to be produced. The organic matrix can in particular be obtained from epoxy resins, such as commercially available high-performance epoxy resins, or from liquid precursors of carbon or ceramic matrices.

[0195] In the case of forming a carbon or ceramic matrix, the heat treatment includes pyrolyzing the organic precursor to convert the organic matrix into a carbon or ceramic matrix according to the precursor used and the pyrolysis conditions. For example, the carbon liquid precursor can be a resin with a relatively high carbon content, such as phenolic resin, while the ceramic liquid precursor, especially the precursor of SiC, can be polycarbosilane (PCS) or polytitanocarbosilane (PTCS) or polysilazane (PSZ) resin. Several consecutive cycles from impregnation to heat treatment can be carried out to achieve the desired degree of densification.

[0196] The densification of the fiber preform can be carried out by the well-known resin transfer molding (RTM) method. According to the RTM method, the fiber preform is placed in a mold having the shape of the cover to be produced. A thermosetting resin is injected into the internal space defined by a rigid material part and the mold, and this internal space includes the fiber preform. In this internal space, a pressure gradient is usually established between the position where the resin is injected and the holes where the resin is discharged to control and optimize the resin impregnation of the preform.

[0197] The resin used can be, for example, epoxy resin. The resins suitable for the RTM method are well known. They preferably have a low viscosity to facilitate their injection into the fibers. The selection of the temperature grade and / or chemical properties of the resin is determined according to the thermomechanical stresses that the part has to withstand. Once the resin is injected into the entire reinforcement, its polymerization is carried out by heat treatment according to the RTM method.

[0198] After injection and polymerization, the part is demolded. Finally, the part is trimmed to remove the excess resin and chamfered to obtain ​The shroud 1010 shown.

[0199] The shroud 1010 is a shroud of an aero gas turbine engine fan. The shroud further includes a reinforcement 480 formed by densification of the above-described deployable portions 441 and 442.

[0200] In addition, the shroud includes an upstream flange 1001 and a downstream flange 1002 formed by the above-described fiber preform portions 62 and 63.

[0201] ​ An aero engine including the shroud 1010 as described above is shown.

[0202] As ​ In such an engine shown highly schematically, in the air flow direction from upstream to downstream, it includes: a fan 81 provided at the engine air inlet, a compressor 82, a combustion chamber 83, a high-pressure turbine 84, and a low-pressure turbine 85. The engine is accommodated in the shroud and includes a plurality of parts corresponding to the various elements of the engine. Thus, the fan 81 is surrounded by the shroud 1010. In addition, as ​ shown, the shroud 1010 includes a reinforcement 480.

[0203] The above description is about the distal end portion P dist of the fiber web.

[0204] In a specific embodiment of the present invention, the fiber web for the present invention may include a specific proximal end portion, which may directly form a flange on the inside of the shroud during shroud manufacturing.

[0205] The following relates to specific embodiments of the proximal end portion of the fiber web, and these embodiments can be combined independently of the above-described embodiments of the distal end portion.

[0206] ​ Such an embodiment is shown.

[0207] ​ A fiber web 900 is shown, the proximal and distal end portions of which include non-interconnected regions but are located on opposite faces.

[0208] As described above, the fiber web can then form a turbine shroud that includes one or more attachment flanges on its inner circumferential surface and one or more reinforcements on its outer surface.

[0209] Therefore, ​ the distal end portion P dist as described above is shown, the deployable portion of which forms a reinforcement 480 on the outer surface F ext .

[0210] Symmetrically, the proximal end portion P proxincluding a flange 180, the flange 180 being formed by one or more deployable proximal ends formed on the inner surface F prox inner surface F int at the proximal end P.

[0211] The proximal end extends between the intermediate region PI1 and the proximal edge 103.

[0212] ​ A specific proximal end of the fibrous web for implementing ​ is shown.

[0213] Only the content for implementing the proximal portion of the fibrous web is described below. According to symmetry, if the above terms for the distal portion are reused without the proximal or distal adjectives, it should be understood that the following applies to the proximal portion.

[0214] ​ Only the proximal end P prox is shown, but it should be understood that for clarity, the distal portion not specifically detailed in ​ conforms to the distal portion as described above, for example, in combination with ​ or ​ the described distal portion.

[0215] In ​ , the fibrous web is strip-shaped, extending a defined length L between the proximal portion 103 and the distal portion 104 in the longitudinal direction X 100 , a defined width l between the first side edge 101 and the second side edge 102 in the transverse direction Y 100 , and extending between the inner surface F int and the outer surface F ext in the thickness Z.

[0216] The fibrous web has a three-dimensional or multi-layer braided structure between multiple warp yarns or strands 20 extending in the longitudinal direction X and multiple weft yarns or strands 30 extending in the transverse direction Y. The fibrous web includes a proximal end P located between the intermediate portion PI1 and the proximal portion 103 prox . The proximal end P prox includes a proximal inner PP int and a proximal outer PP ext in the direction of its thickness Z. The proximal end P prox is arranged such that the proximal inner PP int extends between the inner surface F int and the proximal outer PP ext , and the proximal outer PP ext extends between the proximal inner PP int and the outer surface F ext . The fibrous web includes a proximal inner PP intand at least two proximal non-interconnect regions 121, 122 between the proximal external PP ext and further includes a proximal internal PP int connected to the proximal external PP ext by a proximal connection portion 119, such that the non-interconnected portions 141, 142 of the proximal internal PP int form a deployable proximal portion of the fibrous web around the proximal connection portion 119.

[0217] In the illustrated embodiment, the intermediate portion PI1 starts from the end point 160 of the proximal portion P prox .

[0218] In one embodiment, the point 160 may correspond to the end point of the first turn of the hood preform of the preform formed as shown ​ .

[0219] For ease of description of the fibrous web, ​ a fibrous web having only the proximal connection portion 119 is shown, but it should be understood that this embodiment is not limiting.

[0220] The fibrous web includes a proximal upstream region 110, a proximal intermediate region 120, and a proximal downstream region 130 in the proximal portion P dist , and the fibrous web is arranged such that the proximal upstream region 110 extends between the first side edge 101 and the proximal intermediate region 120, the proximal intermediate region 120 extends between the proximal upstream region 110 and the proximal downstream region 130, and the downstream region 130 extends between the proximal intermediate region 120 and the second side edge 102.

[0221] For example, the width l 110 of the proximal upstream region 110 may be between 5% and 90% of the width l 100 of the fibrous web, depending on the axial position required for the attachment flange.

[0222] For example, the width l 120 of the proximal intermediate region 120 may be between 2% and 10% of the width l 100 of the fibrous web, depending on the axial position required for the attachment flange.

[0223] For example, the width l 130 of the proximal downstream region 130 may be between 5% and 90% of the width l 100 of the fibrous web, depending on the axial position required for the attachment flange.

[0224] In particular, as shown ​ , the widths l 110 and l 130 may not be equal.

[0225] The fibrous web at the proximal end portion P prox also includes a proximal inner portion PP int and a proximal outer portion PP ext , which enables the definition of ​ six regions of the fibrous web visible in: a proximal upstream outer region 171, a proximal upstream inner region 144, a proximal middle inner region, a proximal middle outer region, a proximal downstream outer region 172, and a proximal downstream inner region 145.

[0226] The proximal middle region 120 itself is divided into a proximal connecting portion 119 and two proximal non-interconnecting regions 121, 122.

[0227] Thus, the proximal middle region 120 includes a proximal outer portion 153 and two portions 151 and 152 of the proximal outer, the proximal outer portion 153 is connected to the proximal inner portion 143 through the proximal connecting portion 119, and the two portions 151 and 152 of the proximal outer are non-interconnected with the proximal inner portions 141, 142 located directly below.

[0228] Portion 151 is separated from the proximal portion 141 by the non-interconnecting region 121, and portion 152 is separated from portion 142 by the non-interconnecting region 122.

[0229] In one embodiment, the non-interconnecting region 121 may extend beyond the proximal middle region 120, for example as ​ shown, extending to the first outer edge 101.

[0230] In one embodiment, the proximal upstream outer region 171 and the proximal upstream inner region 144 are non-interconnected by a non-interconnecting region 115 continuous with the non-interconnecting region 121.

[0231] In one embodiment, the non-interconnecting region 122 may extend beyond the proximal middle region 420, for example as ​ shown, extending to the second outer edge 102.

[0232] In one embodiment, the proximal downstream outer region 172 and the proximal downstream inner region 145 are non-interconnected by a non-interconnecting region 117 continuous with the non-interconnecting region 122.

[0233] In one embodiment, the non-interconnecting regions 121 and 122 thus define deployable portions 142 and 141.

[0234] In ​ the described embodiment, the proximal inner portion PP int is provided in the thickness of the fibrous web, in other words, there is no thickness change at the end point 160 of the fibrous web at the proximal end portion P prox .

[0235] In one embodiment, the thickness e of the proximal interior Pint can be between 30% and 60% of the total thickness e of the fibrous web 100 .

[0236] In an embodiment not shown, proximal interior PP int can be added to the fibrous web

[0237] The proximal deployable portions 142 and 141 can form a flange 180 in a manner similar to that in which the distal deployable portion forms the reinforcement 480, as described in connection with ​ and ​ .

[0238] Such a proximal end portion may require adjustment of the impregnation method described above in connection with ​ .

[0239] The following describes a specific case of a fibrous web having only a proximal connection portion 119 and thus only one flange 180, but it should be understood that fibrous webs including multiple proximal connection portions and thus multiple flanges can be treated in a similar manner

[0240] Due to the presence of the flange 180 on the inner surface F of the fiber preform int , the core 710 can be divided into two parts

[0241] In this embodiment, and in a manner similar to the split of the mold into two parts 721 and 722, a first mold part can form a cover portion extending between the first side edge 101 and the flange 180, while a second mold part can form a cover portion extending between the flange 180 and the second side edge 102

[0242] In addition, splitting the mold into two parts ensures easy demolding from the mold without the risk of damaging the flange 180

Claims

1. An aircraft cowling fiber preform, comprising one or more coils of wound fiber mesh (500), the fiber mesh being strip-shaped and extending along a longitudinal direction (X) between a proximal edge (103) and a distal edge (104) to define a length (L 100 ), extending along a transverse direction (Y) between a first side edge (101) and a second side edge (102) to define a width (l 100 ), and extending along a thickness (Z) between an inner surface (F int ) and an outer surface (F ext ). The fibrous web has a three-dimensional or multi-layered braided structure between multi-layered warp or yarns (20) extending in the longitudinal direction and multi-layered weft or yarns (30) extending in the transverse direction, and the fibrous web includes a distal portion (P located between an intermediate portion (PI2) and the distal edge in the longitudinal direction. dist ) The distal end includes an inner portion (PD) in its thickness direction int ), and an outer portion (PD ext ), and is arranged such that: the inner portion extends between the inner surface and the outer portion, and the outer portion extends between the inner portion and the outer surface The fibrous web is characterized in that the outer part is connected to the inner part through at least one connecting part (419), the outer part includes a first deployable part and a second deployable part (441, 442) with a width determined by extending along the transverse direction from the connecting part, the first deployable part is separated from the inner part by a first non-interconnected area (421), and the second deployable part is separated from the inner part by a second non-interconnected area (422). The inner surface (F int ) of the proximal edge (103) of the fibrous web is located on the radially inner surface side of the preform, and the outer surface (F ext ) of the distal edge (104) of the fibrous web is located on the radially outer surface side of the preform.

2. The fiber preform of the aircraft cowling according to claim 1, wherein, The thickness (e) of the exterior Dext is between 160% and 260% of the thickness of the interior.

3. The fiber preform of the aircraft cover according to claim 1 or 2, wherein, The ratio of the distance from the first side edge (101) to the connecting part (419) to the distance from the second side edge (102) to the connecting part is between 10% and 40%.

4. The fiber preform for an aircraft cowling according to any one of claims 1 to 3, wherein, The connecting part (419) is obtained by sewing the outer part onto the inner part, by co-weaving the inner and outer parts, or by needling the outer part onto the inner part.

5. The fiber preform of the aircraft cowling according to any one of claims 1 to 4, wherein, The distal end portion includes an upstream region (410), a middle region (420), and a downstream region (430) in the width direction, and is arranged such that: the upstream region extends between the first side edge and the middle region, the middle region extends between the upstream region and the downstream region, the downstream region extends between the middle region and the second side edge, the middle region includes all of the connecting parts (419), and wherein the middle region includes weft yarns and / or warp yarns having different properties from other yarns of the fibrous web.

6. The fiber preform of the aircraft fairing according to claim 5, wherein, The yarns of the fibrous web are selected from carbon fiber bundles having an intermediate modulus (300 GPa), and wherein the middle region includes carbon fiber weft yarns and / or warp yarns having a high modulus (450 GPa).

7. The aircraft cowling fiber preform according to any one of claims 1 to 6, wherein, The width by which the first deployable part and the second deployable part (441, 442) extend along the transverse direction from the connecting part (419) is 1% to 5% of the width of the fibrous web.

8. The aircraft cowl fiber preform (900) according to any one of claims 1 to 7, wherein, The fibrous web further includes a proximal end portion (P) that is located in the longitudinal direction between the proximal edge (103) and the intermediate portion (PI1). prox ) The proximal end portion includes a proximal inner part and a proximal outer part in its thickness direction, and is arranged such that: the proximal inner part (PP int ), extends between the inner surface (F int ), and the proximal outer part (PP ext ), and the proximal outer part extends between the proximal inner part and the outer surface (F ext ). Wherein, the proximal outer part is connected to the proximal inner part through at least one proximal connecting part (119), the proximal outer part includes a first proximal deployable part and a second proximal deployable part (141, 142) with a width determined by extending along the transverse direction from the proximal connecting part, the first proximal deployable part (141) is separated from the proximal inner part by a first proximal non-interconnected area (121), and the second proximal deployable part (142) is separated from the proximal inner part by a second proximal non-interconnected area (122).

9. A method for manufacturing a composite material aircraft cowling (1010), characterized in that, At least includes the following steps: - Arranging the fiber preform according to claim 1 around a cylindrical core (710); - Providing at least one pair of molds on the radially outer part of the fiber preform, the pair of molds including at least one first pair of mold parts (721) and at least one second pair of mold parts (722), and the deployable parts (441, 442) of the fibrous web (500) being located between the first pair of mold parts and the second pair of mold parts; - Forming a matrix in the fibrous web held between the core and the pair of molds.

10. A composite gas turbine shroud (1010), characterized in that, Includes a fiber reinforcement composed of the fiber preform according to claim 1 and a matrix for densifying the fiber reinforcement.

11. An aero gas turbine engine (80), characterized in that, Comprising the cover body (1010) according to claim 10.

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