Aeronautical casing preform comprising a fibrous web with two deployable portions

Abstract

The invention relates to a fibrous 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 face (F int ) and an outer face (F ext ), the fibrous web comprising a distal portion (P dist ) present between an intermediate portion (PI 2 ) and the distal edge along the longitudinal direction, the distal portion comprising, in the direction of its thickness, an internal portion (PD int ) and an external portion (PD ext ), the web being characterized in that the external portion is connected to the internal portion by at least one linking portion (419), the external portion comprising a first deployable portion separated from the internal portion by a first separation (421), and a second deployable portion separated from the internal portion by a second separation (422).

Description

Description AERONAUTICAL CASING PREFORM COMPRISING A FIBROUS TEXTURE WITH TWO DEPLOYMENT PORTIONS Technical Field

[0001] The present invention relates to a method of manufacturing a fibrous texture which can be used, in particular but not exclusively, for forming the fibrous reinforcement of an aeronautical engine fan casing made of composite material. Prior art

[0002] The manufacture of a casing made of composite material begins with the production of a fibrous texture in the form of a strip, the fibrous texture being produced by three-dimensional weaving between a plurality of layers of warp threads and a plurality of layers of weft threads. The fibrous texture thus obtained is wound over several turns on a mold or tool having the shape of the casing to be produced and held between the mold and segments forming the counter-mold so as to obtain a fibrous preform.

[0003] Once the fiber preform has been produced, that is to say at the end of the winding of the fiber texture, the tooling carrying the fiber preform is closed by counter-molds then transported to an oven or furnace in which the densification of the preform by a matrix is ​​carried out, the matrix being able to be obtained in particular by injection and polymerization of a resin in the fiber preform.

[0004] The casings must provide a retention function by containing debris ingested inside the engine, or blades or blade fragments projected by centrifugation, in order to prevent them from passing completely through the casing and high-energy debris from being released.

[0005] In addition, turbomachine casings are subject to significant vibration excitations. Indeed, they house the blades which, during operation, generate strong dynamic excitation due to impacts at the blade tip. It is very important that the casing is capable of handling the dynamic excitation, in in particular preventing the natural vibration modes of the casing from being excited and causing interaction between the rotor and the stator.

[0006] It must also be taken into account that the vibration stress of the casing, and its natural vibration modes, can change with the wear of the turbomachine. For safety reasons, it is very important that the most energetic natural modes of the casing are not excited at any time throughout its lifetime.

[0007] For this, it is possible to have reinforcement zones, to ensure sufficient mechanical strength of the casing.

[0008] However, when the casing is made of composite material, the addition of such reinforcement zones requires adding material to the composite structure, which is not easy with current processes.

[0009] This is why there remains the need to reinforce the casings whose mechanical strength would not be as good as casings of the prior art and the need to obtain these casings more simply than the casings of the prior art. Statement of the invention

[0010] The proposed invention aims to address the above problem.

[0011] For this purpose, the invention relates to a fibrous texture having a strip shape extending in a longitudinal direction over a determined length between a proximal edge and a distal edge, in a lateral direction over a determined width between a first lateral edge and a second lateral edge, and in the thickness between an internal face and an external face, the fibrous texture having a three-dimensional or multi-layer weave between a plurality of layers of warp yarns or strands extending in the longitudinal direction and a plurality of layers of weft yarns or strands extending in the lateral direction, the fibrous texture comprising a distal portion present between an intermediate portion and the distal edge in the longitudinal direction, the distal portion comprising in the direction of its thickness, an internal portion and an external portion, arranged so that the internal portion extends between the face internal and the external portion, and the external portion extends between the internal portion and the external face, the texture being characterized in that the external portion is connected to the internal portion by at least one connecting portion, the external portion comprising first and second deployment portions extending in the lateral direction from the connecting portion over a determined width, the first deployment portion being separated from the internal portion by a first disconnection, the second deployment portion being separated from the internal portion by a second disconnection.

[0012] The fibrous texture according to the invention and in particular its two deployment portions make it possible to form a casing preform comprising a stiffener on an external face of the casing preform, and this directly thanks to the fibrous texture.

[0013] This allows the production of a casing with improved mechanical properties with regard to vibration stresses, and avoids any step of adding an added stiffener during the manufacture of the casing.

[0014] The stiffener is also better connected to the rest of the casing, since it is an integral part of the latter, and does not require any additional fixing or gluing. In this case, we speak of an integrated stiffener.

[0015] In one embodiment, the ratio between the thickness of the outer portion and the thickness of the inner portion is between 150% and 260%.

[0016] In one embodiment, the ratio between the thickness of the outer portion and the thickness of the inner portion is between 160% and 260%.

[0017] 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%.

[0018] This embodiment ensures that the stiffener, formed by the folding of the deployment portions, is located in a place of the fibrous texture, and ultimately of the casing, which allows an increase in the stiffness / casing mass, so as to increase the natural frequencies that could be achieved in the engine operating range.

[0019] In one embodiment, the connecting portion is obtained by sewing the outer portion to the inner portion, by co-weaving the inner and outer portions or by needling an outer portion to the inner portion.

[0020] The connecting portion is essential to allow textile attachment between the outer portion and the inner portion. The connecting portion is present between the untied parts.

[0021] The various textile bonding methods considered all allow this attachment, each providing distinct advantages.

[0022] Obtaining the connecting portion by sewing allows the external portion to be added as an excess thickness to the distal portion of the rest of the fibrous texture.

[0023] This allows the nature of the external portion to be chosen very precisely, and the connecting portion and the disconnections to be located very precisely.

[0024] Obtaining the binding portion by co-weaving ensures a very strong fixation of the outer portion relative to the inner portion. In addition, this allows obtaining a fiber texture as described without the need for an additional step, since the binding portion is created directly during the weaving step of the fiber texture.

[0025] Obtaining the connecting portion by needling represents a less complex step of connecting the external portion than a sewing step and which also does not require modifying the weaving step compared to the methods of the prior art.

[0026] In one embodiment, the distal portion comprises a plurality of connecting portions connecting the outer and inner portions.

[0027] In one embodiment, the distal portion comprises, in the width direction, an upstream zone, an intermediate zone and a downstream zone, arranged such that the upstream zone extends between the first lateral edge and the intermediate zone, the intermediate zone extends between the upstream zone and the downstream zone, and the downstream zone extends between the intermediate zone and the second lateral edge, the intermediate zone comprising all the connecting portions and in which the intermediate zone comprises weft and / or warp threads of a different nature from the other threads of the fibrous texture.

[0028] This embodiment makes it possible to choose yarns of a different nature for the zones intended to form the deployment portions of the fibrous texture, and thus to optimize the particular properties of this zone characteristic of the fibrous texture.

[0029] In one embodiment, the yarns of the outer portion of the intermediate zone are of a different nature, while the rest of the yarns of the distal portion are identical to the yarns of the rest of the fibrous texture.

[0030] In one embodiment, the yarns of the fibrous texture are chosen from carbon strands with intermediate modulus (300 GPa, for example carbon fibers of the HexTow ® IM7 type marketed by the company HEXCEL) and the intermediate zone comprises weft and / or warp yarns made of high modulus carbon (450 GPa, for example carbon fibers of the HexTow ® HM63 type marketed by the company HEXCEL). In this embodiment, the stiffness of the stiffener is thus maximized. Indeed, the stiffness of a beam being a function of the Young's modulus, the section and the length, increasing the modulus amounts to increasing the stiffness. This pushes the natural frequency towards high frequencies because it is a function of the stiffness divided by the mass - the latter being unchanged.

[0031] In one embodiment, the inner and outer portions are separated by distances between 90% and 98% of the texture width.

[0032] This embodiment makes it possible to obtain deployment portions of sufficient length to ensure a further improved stiffener function.

[0033] In one embodiment, the first and second deployment portions extend in the lateral direction from the connecting portion over a width of between 1% and 5% of the width of the fibrous texture.

[0034] The above has been described in relation to the distal portion of the fibrous texture.

[0035] In one embodiment, it is possible to impart additional properties to the fibrous texture by adjusting the proximal portion of the fibrous texture.

[0036] In one embodiment, the fibrous texture comprising a proximal portion present between the proximal edge and an intermediate portion in the longitudinal direction, the proximal portion comprising, in the direction of its thickness, an inner proximal portion and an outer proximal portion, arranged so that the inner proximal portion extends between the inner face and the outer proximal portion, and the outer proximal portion extends between the inner proximal portion and the outer face, in which the outer proximal portion is connected to the inner proximal portion by at least one proximal connecting portion, the outer proximal portion comprising first and second proximal deployment portions extending in the lateral direction from the proximal connecting portion over a determined width, the first proximal deployment portion being separated from the inner proximal portion by a first proximal disconnection,the second proximal deployment portion being separated from the internal proximal portion by a second proximal disconnection.,

[0037] The fibrous texture according to the invention and in particular its two proximal deployment portions make it possible to form a casing preform comprising an attachment flange, on the internal face of the casing preform, and this directly thanks to the fibrous texture.

[0038] This allows for a casing in which the connection to other elements is greatly simplified compared to existing casings.

[0039] The attachment flange is thus much better bonded to the rest of the casing than the metal-composite attachment points of prior art casings, since it is an integral part of the fibrous texture of the casing.

[0040] In one embodiment, the ratio between the thickness of the outer proximal portion and the thickness of the inner proximal portion is between 50% and 170%.

[0041] In one embodiment, the ratio of the distance from the first lateral edge to the proximal connecting portion to the distance from the second lateral edge to the proximal connecting portion is between 10% and 30%.

[0042] This embodiment ensures that the attachment flange, formed by the folding of the proximal deployment portions, is located in a place of the fibrous texture, and ultimately of the casing, which allows the attachment of other elements to the casing in a simplified manner.

[0043] In one embodiment, the proximal connecting portion is obtained by sewing the inner portion to the outer portion, by co-weaving the inner and outer portions or by needling an inner proximal portion to the outer proximal portion.

[0044] The proximal connecting portion is essential to enable textile attachment between the inner proximal portion and the outer proximal portion. The proximal connecting portion is present between the unbound parts.

[0045] The various textile bonding methods considered all allow this attachment, each providing distinct advantages.

[0046] Obtaining the proximal connecting portion by sewing allows the internal proximal portion to be added as an overthickness to the proximal portion of the rest of the fibrous texture.

[0047] This makes it possible to choose very precisely the nature of the external proximal portion, and to locate very precisely the proximal connecting portion and the proximal disconnections.

[0048] Obtaining the proximal bonding portion by co-weaving ensures a very robust fixation of the inner proximal portion relative to the outer proximal portion. In addition, this allows obtaining a fibrous texture as described without the need for an additional step, since the proximal bonding portion is created directly during the weaving step of the fibrous texture.

[0049] Obtaining the proximal connecting portion by needling represents a less complex step of connecting the internal portion than a sewing step and which also does not require modifying the weaving step compared to the methods of the prior art.

[0050] In one embodiment, the proximal portion comprises a plurality of proximal connecting portions connecting the inner and outer proximal portions.

[0051] In one embodiment, the proximal portion comprises, in the width direction, an upstream proximal zone, an intermediate proximal zone and a downstream proximal zone, arranged so that the upstream proximal zone extends between the first lateral edge and the intermediate proximal zone, the intermediate proximal zone extends between the upstream proximal zone and the downstream proximal zone, and the downstream proximal zone extends between the intermediate proximal zone and the second lateral edge, the intermediate proximal zone comprising all the proximal connecting portions and in which the intermediate proximal zone comprises weft and / or warp threads of a different nature from the other threads of the fibrous texture.

[0052] This embodiment makes it possible to choose yarns of a different nature for the zones intended to form the proximal deployment portions of the fibrous texture, and thus to optimize the particular properties of this zone characteristic of the fibrous texture.

[0053] In one embodiment, the yarns of the inner proximal portion of the intermediate proximal portion are of a different nature, while the rest of the yarns of the proximal portion are identical to the yarns of the rest of the fibrous texture.

[0054] In one embodiment, the threads of the fibrous texture are chosen from carbon fibers with an intermediate modulus of the order of 300 GPa such as the HewTow® IM7 fibers marketed by the company HEXCEL and the intermediate proximal zone comprises weft and / or warp threads made of carbon fibers with a high modulus of the order of 450 GPa such as the HewTow® HM63 fibers marketed by the company HEXCEL). In this embodiment, the stiffness of this zone is maximized. By increasing the stiffness of this zone and therefore ultimately of the attachment flange, the mechanical robustness of the latter is increased.

[0055] In one embodiment, the inner and outer proximal portions are debonded over distances between 95% and 99% of the width of the fibrous texture.

[0056] This embodiment makes it possible to obtain proximal deployment portions of sufficient length to form an attachment flange with the desired mechanical properties.

[0057] In one embodiment, the first and second proximal deployment portions extend in the lateral direction from the connecting portion over a width of between 2% and 5% of the width of the fibrous texture.

[0058] According to another of its aspects, the invention relates to a fibrous preform for an aeronautical casing comprising a winding on one or more turns of a fibrous texture as described above, the internal face of the proximal edge of the texture being located on the side of a radially internal face of the preform, and the external face of the distal edge of the texture being located on the side of a radially external face of the preform.

[0059] In one embodiment, the intermediate portion of the fibrous texture is chosen so that it corresponds to the start of the last turn of the winding just described.

[0060] In this embodiment, the stiffener formed by the deployment portions of the fibrous texture is present over the entire external circumference of the casing.

[0061] According to another of its aspects, the invention relates to a method for manufacturing an aeronautical casing made of composite material comprising at least the following steps: - the arrangement of a fiber preform as just described around a cylindrical mandrel; - the arrangement of at least one counter-mold on the radially external part of the fiber preform, said counter-mold comprising at least a first and a second counter-mold part, a deployment portion of the fiber texture being present between the first and the second counter-mold part; - the formation of the matrix in the fibrous texture maintained between the mandrel and the counter-mold.

[0062] In such an embodiment, the aircraft casing is manufactured directly with a stiffener.

[0063] That is to say, it is not necessary to add a stiffener to the casing, the stiffener being created directly during the formation of the matrix in the fibrous texture, and more precisely in the deployment portions of the fibrous texture.

[0064] In addition, the counter-mold includes a geometry adapted to the deployment portion.

[0065] In one embodiment where the fibrous texture comprises several connecting portions, the counter-mold may comprise more than two parts such that each stiffener, i.e. the two deployment portions formed by a connecting portion, are present between two distinct counter-mold parts.

[0066] These separate counter-mold parts allow easy demolding of the casing, once the die has been formed.

[0067] In one embodiment, the matrix is ​​of an organic type such as epoxy resin, such as for example the PR 520N RTM resin marketed by the company Solvay SA.

[0068] According to another of its aspects, the invention relates to a gas turbine casing made of composite material comprising a fibrous reinforcement consisting of a fibrous preform as described above, and a matrix densifying the fibrous reinforcement.

[0069] Such an embodiment makes it possible to have a gas turbine casing whose stiffeners are directly manufactured during the formation of the casing, which allows an improvement in the mechanical characteristics of the casing, without the need to add stiffeners to an already formed casing.

[0070] The casings according to the invention are therefore less complex to manufacture than the casings of the prior art, and the stiffeners are fixed to them more reliably.

[0071] According to another of its aspects, the invention relates to an aeronautical gas turbine engine comprising a casing as described above. Brief description of the drawings [Fig. 1] Figure 1 schematically represents a loom possibly used for the manufacture of a fibrous texture according to the invention. [Fig. 2] Figure 2 shows a fibrous texture in one embodiment of the invention. [Fig. 3] Figure 3 shows a fibrous texture in an embodiment of the invention different from that of Figure 2. [Fig. 4] Figure 4 schematically represents a sectional view of a fibrous texture in one embodiment of the invention. [Fig. 5] Figure 5 schematically represents an operation of deploying deployment portions of a texture according to an embodiment of the invention. [Fig. 6] Figure 6 schematically represents a fibrous texture described in Figure 2 whose deployment portions have been deployed. [Fig. 7] Figure 7 schematically represents a fibrous texture described in Figure 3 whose deployment portions have been deployed. [Fig. 8] Figure 8 schematically represents the production of a fibrous casing preform from a fibrous texture. [Fig. 9] Figure 9 represents a particular sectional view of Figure 8. [Fig. 10] Figure 10 schematically represents the arrangement of a fiber preform ready for impregnation in one embodiment of the invention. [Fig. 11] Figure 11 schematically represents a turbomachine casing in one embodiment of the invention. [Fig. 12] Figure 12 schematically represents a turbomachine in one embodiment of the invention. [Fig. 13] Figure 13 schematically represents a fibrous texture in one embodiment of the invention. [Fig. 14] Figure 14 schematically represents a fibrous texture in one embodiment of the invention. Description of the embodiments

[0072] The invention is now described by means of figures, present for descriptive purposes to illustrate certain embodiments of the invention and which should not be interpreted as limiting the latter.

[0073] In particular, the figures are neither to scale nor even to relative scale and only serve to illustrate the embodiments described below.

[0074] As shown in Figure 1, a fibrous texture is produced in a known manner by weaving using a Jacquard type loom 5 on which a bundle of warp threads or strands 20 has been arranged in a plurality of layers, the warp threads being linked by weft threads or strands 30.

[0075] In Figure 1, the weft threads 30 are shown in the lateral direction Y, and the warp threads 20 in the longitudinal direction X.

[0076] It should be noted, however, that the terms "weft threads" or "warp threads" are only naming conventions, and that the occurrences of "weft" and "warp" could be interchanged here and in the rest of the application.

[0077] Figure 2 shows a fibrous texture 500 in one embodiment of the invention.

[0078] The fibrous texture 500 has a strip shape extending in a longitudinal direction X over a determined length Li 00 between a proximal edge 103 and a distal edge 104, in a lateral direction Y over a determined width 100 between a first lateral edge 101 and a second lateral edge 102, and in the thickness Z between an internal face F in t and an external face F ex t-

[0079] The fibrous texture has a three-dimensional or multi-layer weave between a plurality of layers of warp yarns or strands 20 extending in the longitudinal direction X and a plurality of layers of weft yarns or strands 30 extending in the lateral direction Y, the fibrous texture 500 comprising a distal portion P dist present between an intermediate part PI2 and the distal part 104, the distal portion P d ist comprising in the direction of its thickness Z, an internal portion PDint and an external portion PD ex t, arranged so that the internal portion PDint extends between the internal face F in t and the external portion PD ex t, and the external portion PD ex t extends between the internal portion PD in t and the external face F ex t, the texture 500 comprising at least two disconnections 421, 422 between the internal portion PD in t and the external portion PD ex t, and in that it further comprises a connecting portion 419 connecting the internal portion PD in t to the external portion PD ex t, so that the loose parts 441, 442 of the external portion PD ext form deployment portions of the fibrous texture around the connecting portion 419.

[0080] In the embodiment shown, the intermediate portion PI2 begins at the starting point 460 of the distal portion.

[0081] In one embodiment, the starting point of the distal portion 460 may correspond to the starting point of the last turn of a casing preform, as will be described in connection with FIG. 10.

[0082] To facilitate the description of the texture 500, a fibrous texture having only one connecting portion 419 is shown in FIG. 2, but it should be understood that this embodiment is not limiting of the invention.

[0083] Texture 500 comprises, in the distal part P dis an upstream zone 410, an intermediate zone 420 and a downstream zone 430, arranged so that the upstream zone 410 extends between the first lateral edge 101 and the intermediate zone 420, the intermediate zone 420 extends between the upstream zone 410 and the downstream zone 430, and the downstream zone 430 extends between the intermediate zone 420 and the second lateral edge 102.

[0084] For example, the width l 4i0 of the upstream zone 410 can be between 10% and 70% of the width li 00 of texture 500 according to the desired axial position for the stiffener.

[0085] For example, the width I420 of the intermediate zone 420 may be between 2% and 10% of the width l 1O o texture 500 depending on the axial position and the desired height for the stiffener.

[0086] For example, the width l 430 of the downstream zone 430 can be between 30% and 85% of the width li 00of texture 500 according to the desired axial position for the stiffener.

[0087] In one embodiment, and as shown in Figure 2, the widths l40 and l 430 may not be equal.

[0088] The texture 500 further comprises, in the distal part Pdist, an internal portion PD in t and an external portion PD ex t, respectively on the side of the internal face Fjnt and the external face F ex t, which makes it possible to define six zones of the fibrous texture visible in figure 2. The internal upstream portion 471, the external upstream portion 444, the internal intermediate zone, the external intermediate zone, the internal downstream portion 472 and the external downstream portion 445.

[0089] The intermediate zone 420 is itself divided into smaller zones by the connecting portion 419 and the two unconnections 421, 422.

[0090] Thus, the intermediate zone 420 comprises an inner portion part 453 linked to the outer portion part 443 by the connecting portion 419 and two parts of the inner portion 451 and 452 which are detached from the parts located directly above and in the outer portion 441 and 442 and separated from the latter by the detachments 421 and 422.

[0091] In the case of a three-dimensional or multi-layer weave as in the example described here, one part is said to be "untied" from another when no thread, neither weft nor warp, forms a textile bond between the two untied parts while the two parts were previously linked together, that is to say that the untiedness is formed during weaving. The two parts are then said to be separated by an untiedness.

[0092] In the present invention, one part is also said to be "untied" from another, in the general case where there is no textile connection between the two parts, that is to say when one of these two parts is added after weaving. A portion of the added part being linked to the other part, for example by needling, on a connection zone, the rest of the added part (outside the connection zone) will be said to be detached from the other part.

[0093] Part 451 is separated from part 441 by the unconnection 421 and part 452 is separated from part 442 by the unconnection 422.

[0094] In one embodiment, the decoupling 421 may extend beyond the intermediate zone 420, for example as shown in FIG. 2, to the first external edge 101.

[0095] In one embodiment, the internal upstream portion 471 and the external upstream portion 444 are unlinked by the unlinking 415 extending the unlinking 421.

[0096] In one embodiment, the decoupling 422 may extend beyond the intermediate zone 420, for example as shown in FIG. 2, to the second outer edge 102.

[0097] In one embodiment, the internal downstream portion 472 and the external downstream portion 445 are detached by the detachment 417 extending the detachment 422.

[0098] In one embodiment, the disconnections 421 and 422 thus define the deployment portions 442 and 441.

[0099] Figure 2 also shows a box IV corresponding to the section which will be presented in Figure 4.

[0100] In the embodiment described in Figure 2, the external part PD ext is arranged in the thickness of the texture, that is to say that the texture 500 has no variation in thickness at the point 460 of the start of the distal portion Pdist-

[0101] In one embodiment, the thickness of the outer portion e Dex t can be between 60% and 72% of the total thickness eioo of the texture 500.

[0102] Figure 3 shows an alternative embodiment of a texture 500.

[0103] Figure 3 is similar to Figure 2, except that the inner portion PD in t of the distal portion P d ist corresponds to the extension of the rest of the fibrous texture. In other words, the external portion PD ex t is arranged in excess of the internal portion PD in t, and the internal portion PD in has a thickness equal to the thickness eioo of the remainder of the texture 500, that is to say the portion of the texture extending between the proximal edge 103 and the point 460.

[0104] In this embodiment, the thickness of the external portion e De xt can be between 150% and 260% of the total thickness ei 00 of texture 500.

[0105] In one embodiment, the variation in thickness of the fibrous texture 500 may be progressive from the starting point of the distal portion 460, for example over a length of 15 cm on either side of the point 460.

[0106] In one embodiment, the outer portion of the distal portion PD ex t is reported on the internal part of the distal portion PDint.

[0107] For example, the external part PD ext is reported after creation of the rest of the texture and fixed on the internal part PD int by the connecting portion 419, for example produced by sewing or needling.

[0108] This embodiment makes it possible to avoid any complex operation of creating a delinking at the time of weaving since in fact, if the external part PDext is fixed to the texture after its creation it is by definition delinked, except at the fixing points.

[0109] In addition, this allows to specifically choose the fibers composing the external PD part ex t for example of a different nature from the rest of the fibrous texture, and this to ensure better mechanical properties for example.

[0110] Figure 4 illustrates in more detail the distal portion Pdist, in a sectional view identified by box IV in Figure 3. [YES] The distal part Pdist includes an external part PD ex t and an internal part PD int, identified in figure 4. Between the two internal edges, we also find the upstream 410, intermediate 420 and downstream 430 zones.

[0112] Figure 4 also shows the internal upstream portion 471, the external upstream portion 444, the internal intermediate zone (451, 452 and 453), the external intermediate zone (441, 442 and 443), the internal downstream portion 472 and the external downstream portion 445.

[0113] Figure 4 further shows distinctly the warp threads 20 and the weft threads 602, 603, 606.

[0114] The weft threads are identified in Figure 4 by several numerical markers according to their configurations with respect to the warp threads 20.

[0115] In one embodiment, the weft threads 602 of the internal portion PDint weave the warp threads 20 of the internal portion PDint in a three-dimensional weave.

[0116] By "three-dimensional weaving" or "3D weaving" is meant here a weaving method by which at least some of the warp threads bind weft threads over several weft layers, such as an "interlock weave". By "interlock weave" is meant here a 3D weave weave in which each warp layer binds several weft layers with all the threads in the same warp column having the same movement in the plane of the weave.

[0117] This allows in particular to have a weaving of the weft threads identical to the rest of the fibrous texture.

[0118] In one embodiment, which is that shown in Figure 4, the weft threads 606 of the outer portion PD ex t, may be non-binding in the external upstream portion 444 and the external downstream portion 445.

[0119] Indeed, since they are separated from the internal upstream 471 and internal downstream 472 portions by the disconnections 415 and 417, and since they will not necessarily be part of the deployment portions 441 and 442, the threads of the external upstream 444 and external downstream 445 portions are intended to be cut, and it is therefore not necessary to weave them.

[0120] For example, cutouts 501 and 502 may be made at the edge of the intermediate zone 420. The result of these cutouts will be described in connection with figure 5, which will present a detailed view of the frame marked by the symbol V in figure 4.

[0121] In one embodiment, the weft threads of the parts 441, 442 and 443 of the outer portion PD ex t of the intermediate zone 420 form a three-dimensional weave with the warp threads.

[0122] This makes it possible to obtain deployment portions 441 and 442 which have excellent properties and very good resistance.

[0123] Furthermore, Figure 4 shows details of the weaving in the intermediate zone 420. In one embodiment which is the one shown, the zone 441 (respectively 442) is detached from the zone 451 (respectively 452), and this is due to the detachment 421 (respectively 422) extending the detachment 415 (respectively 417).

[0124] In fact, none of the weft threads of the external intermediate zone 441 (or 442) is linked to a warp thread of the internal intermediate zone 451 (or 452).

[0125] On the contrary, at the level of the connecting portion 419, the weft threads of the external intermediate zone 443 are linked to warp threads of the internal intermediate zone 453. The weaving 603 is represented here schematically, but it is understood that a connecting portion 419 is thus formed, putting an end to the unlinkings 421 and 422.

[0126] The connecting portion 419 is here shown as a co-weaving of the yarns 603 passing through the connecting portion 419, but the particular effect of the connecting portion 419 comprising weft yarns of the portion 443 with warp yarns of the portion 453 can be obtained by other textile methods, notably needling or sewing.

[0127] The effect of this linking portion 419 is described in detail with the description of Figure 5.

[0128] Figure 5 shows the intermediate zone 420. More specifically, it shows the step of deploying the deployment portions 441 and 442.

[0129] Due to the delinks 421 and 422, the deployment portions 441 and 442 can be deployed around the connection portion 419. This forms a texture with a more complex geometry than the initial texture.

[0130] Figure 5 shows the deployment portions 441 and 442 after cuts 501 and 502 have been made.

[0131] In one embodiment, the length of the deployment portions is chosen according to the stiffening characteristics that one wishes to obtain according to the purpose of the fibrous texture.

[0132] For example, if the texture is intended to form an aeronautical casing preform, the deployment portions may have a length between 1.8 xnx R and 2.2 xnx R, R being the radius of the outer skin of the casing.

[0133] In other words, the deployment portions may have a length between 90% and 110% of the length of the outer skin of the casing.

[0134] The cutouts 501 and 502 then mark the ends of the deployment portions 441 and 442. For example, the cutouts 501 and 502 are made along the entire length of the distal portion P dist, on a thickness corresponding to the thickness e De xt of the external part PD ex t-

[0135] In other embodiments, and in particular when there is more than one connecting portion, the deployment portions may extend to the first inner edge 101, or to the second inner edge 102, without requiring cutting.

[0136] However, other cuts can then be made in the intermediate zone 420 and between two connection portions, in order to form deployment portions.

[0137] Figure 6 represents the fibrous texture obtained after carrying out the cutting and deployment operations of the deployment portions 441 and 442.

[0138] Figure 6 corresponds more precisely to a fibrous texture of Figure 2, after all the shaping operations of the deployment portions 441 and 442.

[0139] In particular, it will be noted that at point 460 where the distal part P begins d ist of the fibrous texture, we observe a reduction in the thickness 461.

[0140] Indeed, compared to the initial fibrous texture, that of figure 2, the external upstream 444 and downstream 445 portions have been removed.

[0141] Since these counted in the thickness of the distal part P diS t of the fibrous texture, the distal part Pdist is less thick once the upstream external portions 444 and downstream 445 are removed.

[0142] The distal part Pdist after deployment of the deployment portions therefore only includes the internal portion PD iri t composed of zones 471, 451, 453, 452 and 472 described above.

[0143] In one embodiment, the deployment portions 441 and 442 together form a stiffener 480.

[0144] The stiffener 480 is held to the remainder of the fiber texture by the connecting portion 419.

[0145] The rest of the fibrous texture remains the same as described above.

[0146] In an alternative embodiment, which is shown in Figure 7, the stiffener 480 may be formed without decreasing the thickness of the texture at the starting point 460 of the distal portion Pdist-

[0147] This is particularly the case when the internal portion PD in t of the fibrous texture has a thickness similar to the rest of the fibrous texture, for example that shown in Figure 3, in an embodiment where the external portion PD ex t is reported on the internal portion PD in t by sewing or needling.

[0148] In any event, the deployment of the deployment portions 441 and 442 makes it possible to form the stiffener 480.

[0149] Figure 8 illustrates a step of arranging a fibrous texture 500 as described above on a mold 50 in order to form a turbomachine casing preform.

[0150] The mold 50 may include a mandrel 710 having the shape of the casing to be formed.

[0151] Figure 8 illustrates a casing fiber reinforcement which is formed by winding the previously described fiber texture 500 onto a mold 50, the fiber reinforcement constituting a complete tubular fiber preform of a casing forming a single piece. Here, in particular, we see the arrangement of the distal portion of a texture 500 on the mandrel 710.

[0152] The mold 50 comprises a mandrel 710, having an external surface 51 whose profile corresponds to the internal surface of the casing to be produced.

[0153] The internal face F int of the texture 500 is disposed on the outer surface 51 of the mandrel 710, and the texture 500 is then wound from its proximal edge 103 to its distal edge 104.

[0154] In Figure 8, two arrows symbolize the rotation of the mandrel 710 to be carried out to form the texture. Of course, the texture can also be arranged while leaving the mandrel fixed.

[0155] The mandrel 710 also comprises two flanges 52 and 53 to form ends of the fiber preform corresponding to the flanges of the casing, respectively the downstream flange 62 and the upstream flange 63.

[0156] The portions of fiber preform corresponding to the flanges 62, 63 of the casing end with the second lateral edge 102 and the first lateral edge 101 respectively.

[0157] Figure 9 represents a section of the fibrous texture deposited on the mold 50 visualized by frame IX in Figure 8.

[0158] The mold 50 comprises the mandrel 710 and further comprises a first counter-mold portion 721 and a second counter-mold portion 722.

[0159] Figure 9 illustrates the particular case of a texture comprising only one connecting portion 419, and consequently having only one stiffener 480, but it should be understood that textures comprising several connecting portions, and therefore several stiffeners, could be treated in a similar manner.

[0160] In the embodiment illustrated in FIG. 9, the first counter-mold part 721 makes it possible to give shape to the portion of casing extending between the first lateral edge 101 and the stiffener 480, while the second counter-mold part 722 makes it possible to give shape to the portion of casing extending between the stiffener 480 and the second lateral edge 102.

[0161] Furthermore, the separation of the counter-mold into two parts 721, 722 ensures easy demolding of the mold without risk of damaging the stiffener 480.

[0162] Figure 10 illustrates in another view the winding of a fibrous texture 500 on a mandrel 710.

[0163] The fibrous texture 500 is wound onto the mandrel starting from its proximal edge 103, the internal face F in t of the texture being arranged on the external face 51 of the mandrel 710. The winding gives rise to several turns of the texture to form the preform until the arrangement of the distal part P d ist as shown in Figure 10.

[0164] In the illustrated embodiment, the distal portion P d ist starts at point 460, which represents the start of the last turn of the fiber texture on mandrel 710.

[0165] This embodiment ensures that the stiffener 480 formed by the deployment portions 441, 442 of the distal part Pdist of the texture 500 is present over the entire last turn, and ultimately over the entire circumference of the casing.

[0166] In an alternative embodiment, it may be preferred to have stiffener 480 only on a portion of the circumference of the casing, and for this it is sufficient to arrange point 460 closer to the distal edge 104.

[0167] The mandrel 710 shown in Figure 10 also has the counter-mold 721 opposite it.

[0168] In this case, the counter-mold 721 comprises a plurality of counter-mold sectors (all marked 721) and together forming a counter-mold 721 for the entire circumference of the mandrel 710.

[0169] For example, once the fibrous texture 500 is arranged on the mandrel 710 to form a fibrous preform for a turbomachine casing, the preform can then be densified by a matrix.

[0170] The densification of the fibrous preform consists of filling the porosity of the preform, in all or part of its volume, with the material constituting the matrix.

[0171] The matrix can be obtained in a manner known per se using the liquid process. The liquid process consists of impregnating the preform by a liquid composition containing an organic precursor of the matrix material. The organic precursor is usually in the form of a polymer, such as a resin, optionally diluted in a solvent. The fiber preform is placed in a mold that can be sealed with a housing having the shape of the final molded part. As illustrated in Figure 10, the fiber preform is here placed between a plurality of sectors 721 and 722 forming the counter-mold and the mandrel 710 forming a support, these elements having respectively the external shape and the internal shape of the casing to be produced. Then, the liquid matrix precursor, for example a resin, is injected throughout the housing to impregnate the preform.

[0172] The transformation of the precursor into an organic matrix, namely its polymerization, is carried out by heat treatment, generally by heating the mold, after removal of any solvent and crosslinking of the polymer, the preform being always maintained in the mold having a shape corresponding to that of the part to be produced. The organic matrix can be obtained in particular from epoxy resins, such as, for example, the high-performance epoxy resin sold, or from liquid precursors of carbon or ceramic matrices.

[0173] In the case of carbon or ceramic matrix formation, the heat treatment consists of pyrolyzing the organic precursor to transform the organic matrix into a carbon or ceramic matrix depending on the precursor used and the pyrolysis conditions. For example, liquid carbon precursors can be resins with a relatively high coke content, such as phenolic resins, while liquid ceramic precursors, particularly SiC, can be polycarbosilane (PCS) or polytitanocarbosilane (PTCS) or polysilazane (PSZ) resins. Several consecutive cycles, from impregnation to heat treatment, can be carried out to achieve the desired degree of densification.

[0174] The densification of the fiber preform can be carried out by the well-known process of transfer molding called RTM ("Resin Transfer Molding"). According to the RTM process, the fiber preform is placed in a mold having the shape of the casing to be produced. A thermosetting resin is injected into the internal space delimited between the rigid material part and the mold and which includes the fiber preform. A pressure gradient is generally established in this internal space between the place where the resin is injected and the resin discharge orifices in order to control and optimize the impregnation of the preform by the resin.

[0175] The resin used can be, for example, an epoxy resin. Resins suitable for RTM processes are well known. They preferably have a low viscosity to facilitate their injection into the fibers. The choice of temperature class and / or the chemical nature of the resin is determined according to the thermomechanical stresses to which the part must be subjected. Once the resin has been injected throughout the reinforcement, it is polymerized by heat treatment in accordance with the RTM process.

[0176] After injection and polymerization, the part is demolded. The part is finally trimmed to remove excess resin and the chamfers are machined to obtain a 1010 housing shown in Figure 11.

[0177] The casing 1010 is a casing of a gas turbine aeronautical engine fan. The casing further comprises a stiffener 480 formed by the densification of the deployment portions 441 and 442 described above.

[0178] Furthermore, the casing comprises an upstream flange 1001 and a downstream flange 1002, formed by the fiber preform portions 62 and 63 described above.

[0179] Figure 12 illustrates an aircraft engine including a casing 1010 as described.

[0180] Such an engine, as shown very schematically in Figure 12, comprises, from upstream to downstream in the direction of the gas flow, a fan 81 arranged at the inlet of the engine, a compressor 82, a combustion chamber 83, a high-pressure turbine 84 and a low-pressure turbine 85. The engine is housed inside a casing comprising several parts corresponding to different elements of the engine. Thus, the fan 81 is surrounded by the casing 1010. In addition, and as shown in FIG. 12, the housing 1010 includes a stiffener 480.

[0181] What has been described above has been in relation to the distal part Pdist of the fibrous texture.

[0182] In a particular embodiment of the present invention, the fibrous texture used for the present invention may comprise a particular proximal portion to enable a flange to be formed directly during the manufacture of the casing on the internal portion of the casing.

[0183] The following relates to a particular embodiment of a proximal portion of fibrous texture whose embodiments are independently combinable with the embodiments described above for the proximal portion.

[0184] Figure 13 illustrates such an embodiment.

[0185] Figure 13 illustrates a fibrous texture 900 whose proximal and distal portions include debonds but on opposite faces.

[0186] As described above, the fibrous texture then makes it possible to form turbomachine casings comprising one or more attachment flanges on their internal circumferences and one or more stiffeners on their external circumferences.

[0187] Figure 13 thus illustrates a distal portion P d ist as described above, the deployment portions of which form a stiffener 480 on the external face F ex t-

[0188] Symmetrically, the proximal part P prO x of the fibrous texture comprises a flange 180 formed by one or more proximal deployment portions formed in the proximal portion P pr ox on the inner face F in t.

[0189] The proximal portion extends between an intermediate zone Fold and the proximal edge 103.

[0190] Figure 14 illustrates a particular proximal portion for achieving a fibrous texture of Figure 13.

[0191] The following, and only the following, is described to particularize the proximal part of a fibrous texture. If, by symmetry, terms already used above for the distal part have been reused without the adjective proximal or distal, it should be understood that what follows relates to the proximal part.

[0192] Figure 14 illustrates only the proximal portion P pr ox but it must be understood that the distal part, which is not particularized in figure 14 for reasons of readability, is consistent with a distal part as described above, for example in connection with figures 2 or 3.

[0193] In Figure 14, the fibrous texture has a strip shape extending in a longitudinal direction X over a determined length Li 00between a proximal portion 103 and a distal portion 104, in a lateral direction Y over a determined width li 00 between a first lateral edge 101 and a second lateral edge 102, and in the thickness Z between an internal face F in t and an external face F ex t-

[0194] The fibrous texture has a three-dimensional or multi-layer weave between a plurality of layers of warp yarns or strands 20 extending in the longitudinal direction X and a plurality of layers of weft yarns or strands 30 extending in the lateral direction Y, the fibrous texture comprising a proximal portion P pr ox presents between an intermediate part Pli and the distal part 104, the proximal portion P prO x comprising in the direction of its thickness Z, an internal proximal portion PPint and an external proximal portion PP ex t, arranged so that the inner proximal portion PP int extends between the internal face F in t and the external proximal portion PP ex t, and the external proximal portion PP ex t extends between the inner proximal portion PP in t and the external face F ex t, the texture comprising at least two proximal delinks 121, 122 between the internal proximal portion PP in t and the external proximal portion PP e xt, and in that it further comprises a proximal connecting portion 119 connecting the internal proximal portion PP in t to the external proximal portion PP ex t, so that the detached portions 141, 142 of the inner proximal portion PPint form proximal deployment portions of the fibrous texture around the proximal connecting portion 119.

[0195] In the embodiment shown, the intermediate portion Pli begins at the end point 160 of the proximal portion P prO x. Tl

[0196] In one embodiment, point 160 may correspond to the end point of the first turn of a casing preform, of a preform formed as shown in Figure 10.

[0197] To facilitate the description of the texture, a fibrous texture having only a proximal connecting portion 119 is shown in Figure 14, but it should be understood that this embodiment is not limiting.

[0198] The texture includes, in the proximal part P pr ox an upstream proximal zone 110, an intermediate proximal zone 120 and a downstream proximal zone 130, arranged so that the upstream proximal zone 110 extends between the first lateral edge 101 and the intermediate proximal zone 120, the intermediate proximal zone 120 extends between the upstream proximal zone 110 and the downstream proximal zone 130, and the downstream zone 130 extends between the intermediate proximal zone 120 and the second lateral edge 102.

[0199] For example, the width ln0 of the upstream proximal zone 110 can be between 5% and 90% of the width l 1O o of the texture according to the desired axial position for the attachment flange.

[0200] For example, the width li2o of the intermediate proximal zone 120 may be between 2% and 10% of the width li 00 of the texture according to the desired axial position for the attachment flange.

[0201] For example, the width li 30 of the downstream proximal zone 130 can be between 5% and 90% of the width l 1O o of the texture according to the desired axial position for the attachment flange.

[0202] In particular, and as shown in Figure 2, the widths ln0 and Ii3o may not be equal.

[0203] The texture further includes, in the proximal part P prO x an internal proximal potion PPint and an external proximal portion PP exwhich makes it possible to define six zones of the fibrous texture visible in figure 2. The external upstream proximal portion 171, the internal upstream proximal portion 144, the internal intermediate proximal zone, the external intermediate proximal zone, the external downstream proximal portion 172 and the internal downstream proximal portion 145.

[0204] The intermediate proximal zone 120 is itself divided by the proximal connecting portion 119 and the two proximal disconnections 121, 122.

[0205] Thus, the intermediate proximal zone 120 comprises an outer proximal portion part 153 linked to the inner proximal portion part 143 by the connecting proximal portion 119 and two outer proximal portion parts 151 and 152 which are detached from the parts located directly below and in the inner proximal portion 141 and 142.

[0206] The portion 151 is separated from the proximal portion 141 by the disconnection 121 and the portion 152 is separated from the portion 142 by the disconnection 122.

[0207] In one embodiment, the decoupling 121 may extend beyond the intermediate proximal zone 120, for example as shown in FIG. 2, to the first external edge 101.

[0208] In one embodiment, the outer upstream proximal portion 171 and the inner upstream proximal portion 144 are unlinked by the unlinking 115 extending the unlinking 121.

[0209] In one embodiment, the decoupling 122 may extend beyond the intermediate proximal zone 420, for example as shown in FIG. 2, to the second outer edge 102.

[0210] In one embodiment, the outer downstream proximal portion 172 and the inner downstream proximal portion 145 are unlinked by the unlinking 117 extending the unlinking 122.

[0211] In one embodiment, the disconnections 121 and 122 thus define the deployment portions 142 and 141.

[0212] In the embodiment described in figure 2, the internal proximal part PPint is arranged in the thickness of the texture, that is to say that the texture has no variation in thickness at the end point 160 of the proximal portion P prO x.

[0213] In one embodiment, the thickness of the inner proximal portion epint may be between 30% and 60% of the total thickness eioo of the texture.

[0214] In an embodiment not shown, the internal proximal part PPint can be attached to the fibrous texture.

[0215] The proximal deployment portions 142 and 141 may form the flange 180 in a manner analogous to how the distal deployment portions form the stiffener 480, and as described in connection with Figures 4 and 5.

[0216] Such a proximal portion may require adjustments to the impregnation process, described above in connection with Figures 8 to 11.

[0217] We describe below the particular case of a texture comprising only one proximal connection portion 119, and consequently having only one flange 180, but it should be understood that it would be possible to treat textures comprising several proximal connection portions, and therefore several flanges, in a similar manner.

[0218] Due to the presence of flange 480 on the internal face F in t of the fiber preform, the mold 710 can then be broken down into two parts.

[0219] In this embodiment and in a manner similar to the counter-mold divided into two parts 721 and 722, the first mold part makes it possible to give the shape to the portion of casing extending between the first lateral edge 101 and the flange 180, while the second mold part makes it possible to give the shape to the portion of casing extending between the flange 180 and the second lateral edge 102.

[0220] In addition, the separation of the mold into two parts ensures easy demolding of the mold without risk of damaging the 180 flange.

Claims

Claims

1. Fibrous preform of an aeronautical casing comprising a winding on one or more turns of a fibrous texture (500) having a strip shape extending in a longitudinal direction (X) over a determined length (Li 00 ) between a proximal edge (103) and a distal edge (104), in a lateral direction (Y) over a determined width (li 00 ) between a first lateral edge (101) and a second lateral edge (102), and in the thickness (Z) between an internal face (F in t) and an external face (F ex t), the fibrous texture having a three-dimensional or multi-layer weave between a plurality of layers of warp yarns or strands (20) extending in the longitudinal direction and a plurality of layers of weft yarns or strands (30) extending in the lateral direction, the fibrous texture comprising a distal portion (P dist) present between an intermediate part (PI2) and the distal edge in the longitudinal direction, the distal portion comprising in the direction of its thickness, an internal portion (PDint) and an external portion (PD ex t), arranged so that the inner portion extends between the inner face and the outer portion, and the outer portion extends between the inner portion and the outer face, the texture being characterized in that the outer portion is connected to the inner portion by at least one connecting portion (419), the outer portion comprising first and second deployment portions (441, 442) extending in the lateral direction from the connecting portion over a determined width, the first deployment portion being separated from the inner portion by a first disconnection (421), the second deployment portion being separated from the inner portion by a second disconnection (422), the inner face (F int) of the proximal edge (103) of the texture being located on the side of a radially internal face of the preform, and the external face (F ex t) of the distal edge (104) of the texture being located on the side of a radially external face of the preform.

2. Fibrous preform of an aeronautical casing according to claim 1, in which the ratio between the thickness of the external portion (e D ext) and the thickness of the internal portion is between 160% and 260%.

3. A fibrous aeronautical casing preform according to claim 1 or 2, wherein the ratio between the distance from the first lateral edge (101) to the connecting portion (419) and the distance from the second lateral edge (102) to the connecting portion is between 10% and 40%.

4. Fibrous preform of an aeronautical casing according to any one of claims 1 to 3, in which the connecting portion (419) is obtained by sewing the external portion onto the internal portion, by co-weaving the internal and external portions or by needling an external portion onto the internal portion.

5. Fibrous preform of an aeronautical casing according to any one of claims 1 to 4, in which the distal portion comprises, in the width direction, an upstream zone (410), an intermediate zone (420) and a downstream zone (430), arranged so that the upstream zone extends between the first lateral edge and the intermediate zone, the intermediate zone extends between the upstream zone and the downstream zone, and the downstream zone extends between the intermediate zone and the second lateral edge, the intermediate zone comprising all the connecting portions (419) and in which the intermediate zone comprises weft and / or warp threads of a different nature from the other threads of the fibrous texture.

6. Fibrous preform of an aeronautical casing according to claim 5, in which the threads of the fibrous texture are chosen from carbon strands with an intermediate modulus (300 GPa) and in which the intermediate zone comprises weft and / or warp threads of carbon with a high modulus (450 GPa).

7. Fibrous preform of an aeronautical casing according to any one of claims 1 to 6, in which the first and second deployment portions (441, 442) extend in the lateral direction from the connecting portion (419) over a width of between 1% and 5% of the width of the fibrous texture.

8. Fibrous preform (900) of an aeronautical casing according to any one of claims 1 to 7, in which the fibrous texture further comprises a proximal portion (P prO x) present between the proximal edge (103) and an intermediate part (Fold) in the longitudinal direction, the proximal portion comprising, in the direction of its thickness, an internal proximal portion and an external proximal portion, arranged so that the internal proximal portion (PPint) extends between the internal face (F in t) and the external proximal portion (PP ex t), and the outer proximal portion extends between the inner proximal portion and the outer face (F ext), wherein the outer proximal portion is connected to the inner proximal portion by at least one proximal connecting portion (119), the outer proximal portion comprising first and second proximal deployment portions (141, 142) extending in the lateral direction from the proximal connecting portion over a determined width, the first proximal deployment portion (141) being separated from the inner proximal portion by a first proximal disconnection (121), the second proximal deployment portion (142) being separated from the inner proximal portion by a second proximal disconnection (122).

9. Method for manufacturing an aeronautical casing (1010) made of composite material comprising at least the following steps: - arranging a fiber preform according to claim 1 around a cylindrical mandrel (710); - the arrangement of at least one counter-mold on the radially external part of the fiber preform, said counter-mold comprising at least a first (721) and a second (722) counter-mold part, a deployment portion (441,442) of the fiber texture (500) being present between the first and the second counter-mold part; - the formation of the matrix in the fibrous texture maintained between the mandrel and the counter-mold.

10. Gas turbine casing (1010) made of composite material, comprising a fibrous reinforcement consisting of a fibrous preform according to claim 1, and a matrix densifying the fibrous reinforcement.

11. A gas turbine aero engine (80) comprising a housing (1010) according to claim 10.

Images