Method for manufacturing a fibrous structure with ply separation in a deployed portion and resulting fibrous structure

Abstract

A method for manufacturing a fibrous structure with ply separation in a spread portion and resulting fibrous structure. A three-dimensional weaving method for a fibrous structure (200) by weaving between a plurality of warp yarn layers and a plurality of weft yarn layers comprises weaving a first portion (230) in which all the weft yarn layers are linked together by warp yarns from the plurality of warp layers and at least a second portion (250) adjacent to the first portion, the second portion comprising a base portion (251) and a spread portion (252) separated from each other by a first unlinking (261). The spread portion (252) is separated along the thickness direction (DE) into at least first and second plies (2520, 2521) unlinked by an unlinking (280) extending along the longitudinal direction (DL) in the second portion (250) of the fibrous structure.The first and second plies (2520, 2521) each comprise at least one layer of warp yarns from the plurality of warp yarn layers of the first part of the fibrous structure and at least one layer of weft yarns. Figure for the abstract: Fig. 4.

Description

Title of the invention: Method for manufacturing a fibrous structure with ply separation in a deployment portion and resulting fibrous structure Technical field

[0001] The present invention relates to the production of parts from composite material and more particularly the production by three-dimensional (3D) weaving of fibrous reinforcement structures for such parts. Prior art

[0002] A field of application of the invention is the production of structural composite material parts, i.e. structural parts with fiber reinforcement and densified by a matrix such as organic matrix composite (OMC), carbon matrix (C / C) and ceramic matrix composite (CMC) material parts. Organic matrix composite (OMC), carbon matrix (C / C) and ceramic matrix composite (CMC) materials replace metal material parts in certain parts of turbomachines. Their use contributes to optimizing aircraft performance, in particular by improving the efficiency of the turbomachine and reducing the overall mass of the turbomachine, significantly reducing emissions harmful to the environment (CO, CO2, NOx, etc.) and fuel consumption.

[0003] The invention relates more particularly to the reinforcing fibrous structures obtained by three-dimensional (3D) weaving and which comprise one or more deployment portions, i.e. one or more parts intended to be deployed during the shaping of a fibrous structure.

[0004] An example of this type of fibrous structure is that used to form the fibrous reinforcement of a turbine ring sector made of composite material as disclosed in particular in document US2012027572.

[0005] [Fig.l] illustrates a fibrous structure 10 intended to form the fibrous reinforcement of a turbine ring sector made of composite material. The structure 10 is obtained by three-dimensional weaving between a plurality of layers of warp threads and a plurality of layers of weft threads, the warp threads extending in a longitudinal direction D1 and the weft threads extending in a transverse direction DT. The weft threads are woven in a plurality of columns represented here by lines CT. The columns of weft threads CT are spaced from each other in the longitudinal direction D1, the weft threads of each column of weft threads being juxtaposed in the thickness of the fibrous structure in a superposition direction DSio perpendicular to the longitudinal direction DL.

[0006] The structure 10 comprises a lower part 12 intended to form the base of the ring sector, and an upper part 14 connected to the lower part 12 by a central portion 16. The upper part 14 comprises two deployment portions 141 and 142 present at the opposite lateral ends of the central portion 16 and which are not connected to the lower part 12. In other words, the fibrous structure 10 comprises two delinking zones 18 at two opposite edges in a transverse direction of the structure 10, so as to leave two deployment portions free.

[0007] [Fig. 2] illustrates the shaping of the fibrous structure 10 by folding the deployment portions 141 and 142 at 90° towards the central portion 16 so as to form, after densification, attachment flanges of the ring sector on a ring support structure in a turbine. After folding, the direction of superposition of the weft threads of the weft columns present in the deployment portions 141 and 142 is modified. More precisely, the directions of superposition DSui and DSi42 of the weft threads of the weft columns respectively of the deployment portions 141 and 142 have a significant angular variation with respect to their initial direction of superposition DSi0. The weft columns in the deployment portions 141 and 142 have a shear angle [3 which is between 45° and 60°.This angular variation results from the shear forces which are exerted in the deployment portions 141 and 142 during their deployment, the path at the level of the internal radius R1NT being shorter than the path of the external radius Rext-.

[0008] This angular offset in the columns of weft threads causes a detachment in the fiber structure at a connecting radius, here mainly the internal radius R1NT, as well as a lack of material at the external radius Rext, which is detrimental to the finished part because it creates an area devoid of fiber reinforcement.

[0009] Furthermore, due to the three-dimensional weaving, the angular offset causes shearing of the weft thread columns and, consequently, misalignment in the portions concerned which can disrupt the infiltrability of the resulting preform and modify the initially defined mechanical properties. Statement of the invention

[0010] It is therefore desirable to be able to have a solution for producing fibrous structures which do not have the aforementioned drawbacks.

[0011] To this end, the present invention provides a method of manufacturing a fibrous structure by weaving between a plurality of layers of warp threads and a plurality of layers of weft threads, the warp threads extending in a longitudinal direction, the weft threads extending in a transverse direction, the weft threads being woven in a plurality of columns spaced from each other in the longitudinal direction, the weft threads of each column of weft threads being juxtaposed in the fibrous structure in a thickness direction of said fibrous structure, the fibrous structure comprising a first part in which all the layers of weft threads are linked together by warp threads of the plurality of warp layers by three-dimensional or multi-layer weaving and at least a second part adjacent to the first part in the longitudinal direction, the second part comprising a base portion and a deployment portion separated from each other by a first unlinking extending in the longitudinal direction in the second part of the fibrous structure from a bottom of unlinking adjacent to the first part of the fibrous structure,characterized in that said deployment portion of said at least one second part of the fibrous structure is separated along the thickness direction into at least first and second plies unbound by a second unbound extending along the longitudinal direction in the second part of the fibrous structure from a bottom of unbound adjacent to the first part of the fibrous structure and in that the first and second plies each comprise at least one layer of warp yarns of the plurality of layers of warp yarns of the first part of the fibrous structure and at least one layer of weft yarns, the warp yarns of said at least one layer of warp yarns being woven with the weft yarns of said at least one layer of weft yarns.

[0012] A fibrous structure is thus formed comprising one or more deployment portions which are each divided into a plurality of independent plies, i.e. unbound from one another, which makes it possible to relax the constraints compared to the case where the deployment portion(s) consist of a single 3D woven block. The shear forces applied in the deployed portion(s) are thus significantly reduced, which makes it possible in particular to improve the filling of the internal and external radii. The formation of unbound plies in the deployment portion(s) also improves the positioning accuracy during the formation of the preform, the positioning of each ply being easier than the positioning of a single 3D woven block.

[0013] According to a particular characteristic of the method of the invention, the first and second plies each comprise at least three layers of warp yarns of the plurality of layers of warp yarns of the first part of the fibrous structure and at least three layers of weft yarns, said at least first and second plies being woven by three-dimensional or multi-layer weaving of the warp yarns of said at least three layers of warp yarns with the weft yarns of said at least three layers of weft yarns.

[0014] Each fold being formed by 3D weaving, the properties of 3D weaving are preserved in the deployment portion(s), each fold thus presenting in particular very good resistance to delamination.

[0015] According to another particular characteristic of the method of the invention, the plies each comprise at most four layers of warp yarns of the plurality of layers of warp yarns of the first part of the fibrous structure and four layers of weft yarns. This makes it possible to further reduce the shear forces in each ply of the deployment portion concerned.

[0016] According to another particular characteristic of the method of the invention, the plies are each woven according to one of the following multi-layer weaving patterns: interlock, multi-satin, multi-twill and multi-plain.

[0017] The invention also relates to a method for manufacturing a part made of composite material comprising:

[0018] - weaving a fibrous structure in accordance with the weaving method according to the invention,

[0019] - shaping the fibrous structure by folding the portion(s) of die folding so as to obtain a fibrous preform,

[0020] - densification of the fiber preform by a matrix.

[0021] The method for manufacturing a part made of composite material according to the invention can be used for the manufacture of a turbine ring sector, a stiffener or a fixed or mobile turbomachine blade.

[0022] The invention also relates to a fibrous structure comprising a plurality of layers of warp threads and a plurality of layers of weft threads, the warp threads extending in a longitudinal direction, the weft threads extending in a transverse direction, the fibrous structure comprising a plurality of columns of weft threads spaced from each other in the longitudinal direction, the weft threads of each column of weft threads being juxtaposed in the fibrous structure in a thickness direction of said fibrous structure, the fibrous structure comprising a first part in which all the layers of weft threads are linked together by warp threads of the plurality of warp layers by a three-dimensional or multi-layer weave and at least a second part adjacent to the first part in the longitudinal direction,the second part comprising a base portion and a deployment portion separated from each other by a first uncoupling extending in the longitudinal direction in the second part of the fibrous structure from a bottom uncoupling adjacent to the first part of the fibrous structure, characterized in that said deployment portion of said at least one second part of the fibrous structure is separated in the thickness direction into at least first and second uncoupling plies by a second uncoupling extending in the longitudinal direction in the second, part of the fibrous structure from a debonding bottom adjacent to the first part of the fibrous structure and in that the first and second plies each comprise at least one layer of warp yarns of the plurality of layers of warp yarns of the first part of the fibrous structure and at least one layer of weft yarns, the warp yarns of said at least one layer of warp yarns being woven with the weft yarns of said at least one layer of weft yarns.

[0023] According to a particular characteristic of the fibrous structure of the invention, the first and second plies each comprise at least three layers of warp yarns of the plurality of layers of warp yarns of the first part of the fibrous structure and at least three layers of weft yarns, said at least first and second plies being woven by three-dimensional or multi-layer weaving of the warp yarns of said at least three layers of warp yarns with the weft yarns of said at least three layers of weft yarns.

[0024] According to another particular characteristic of the fibrous structure of the invention, the plies each comprise at most four layers of warp threads of the plurality of layers of warp threads of the first part of the fibrous structure and four layers of weft threads.

[0025] According to another particular characteristic of the fibrous structure of the invention, the plies are each woven according to one of the following multi-layer weaving patterns: interlock, multi-satin, multi-twill and multi-plain.

[0026] The invention also relates to a part made of composite material comprising a fibrous reinforcement densified by a matrix, characterized in that the fibrous reinforcement comprises a fibrous structure according to the invention.

[0027] According to a particular characteristic of the part of the invention, it corresponds to a turbine ring sector, a stiffener or a fixed or mobile turbomachine blade. Brief description of the drawings

[0028] [Fig-1] [Fig.l] is a schematic perspective view of a fibrous structure according to the prior art,

[0029] [Fig.2] [Fig.2] is a schematic front view showing the structure of [Fig.l] after formatting,

[0030] [Fig.3] [Fig.3] is a schematic perspective view of a loom of the type Jacquard used to manufacture a fibrous structure according to the invention,

[0031] [Fig.4] [Fig.4] is a schematic front view of a fibrous structure in accordance with one embodiment of the invention,

[0032] [Fig.5] [Fig.5] is a weave pattern of the fiber structure of [Fig.4]

[0033] [Fig.6] [Fig.6] is a schematic front view of the fibrous structure of [Fig.4] after shaping. Description of the embodiments

[0034] The invention applies generally to the production of fibrous structures or fabrics by three-dimensional (3D) or multi-layer weaving between layers of warp threads and layers of weft threads, the structure comprising at least one portion intended to be deployed during its shaping.

[0035] By "three-dimensional weaving" or "3D weaving" is meant here a weaving method by which at least some of the weft threads bind warp threads over several layers of warp threads or vice versa. An example of three-dimensional weaving is the so-called "interlock" weave. By "interlock" weaving is meant here a weaving weave in which each layer of warp threads binds several layers of weft threads with all the threads of the same warp column having the same movement in the plane of the weave.

[0036] By "multi-layer weave" is meant here a 3D weave with several weft layers whose basic weave of each layer is equivalent to a conventional 2D fabric weave, but with certain points of the weave which link the weft layers together. Examples of known multi-layer weaves which can be used here are in particular those described in documents US2007007386 and US2009186547.

[0037] The yarns used here may in particular be carbon fiber yarns or ceramic fiber yarns such as silicon carbide (SiC) fibers, the invention not being limited to these types of yarns alone.

[0038] [Fig. 3] illustrates a loom 100 equipped with a Jacquard mechanism 101 supported by a superstructure not shown in [Fig. 1]. The loom 100 also comprises a harness 110 consisting of a weaving board 111 and control threads or heddles 113, each heddle 113 being connected at one end to a control hook 1010 of the Jacquard mechanism 101 and at the other end to one of the return springs 102 fixed to the frame 103 of the weaving loom 100. Each heddle 113 comprises an eyelet 114 crossed by a warp thread 203. The heddles 113 and their associated eyelet 114 extend in a zone in which the heddles 113 and the eyelets 114 are animated by a substantially vertical oscillating movement represented by the double arrow F. The heddles 113 are subjected to tensile forces respectively exerted by the control hooks 1010 and by the return springs 102.The heddles 113 allow certain warp threads 203 to be lifted according to a defined weaving program. By lifting certain warp threads 203, the heddles 113 thus create a shed allowing the introduction of weft threads 204 for the 3D or multi-layer weaving of a fibrous texture 200 in the form of a strip or ribbon. The warp threads 201 are . organized into a plurality of layers of warp threads C1 to Cn. A comb 120 present upstream of the shed packs each introduced weft thread by moving from upstream to downstream to a position corresponding to the closing of the shed. The warp threads 203 are brought from bobbins arranged on a creel (not shown in [Fig.3]) upstream of the Jacquard mechanism 101 of the loom 100.

[0039] A method for manufacturing a fibrous structure 200 is now described in accordance with one embodiment. In the example described here, the fibrous structure 200 is intended to form the fibrous reinforcement of a turbine ring sector made of composite material. As illustrated in [Fig. 4], the fibrous structure 200 comprises, once woven, a first portion 230 corresponding here to a central portion of the fibrous structure, a second portion 240 adjacent to the first portion 230 in the longitudinal direction DL and forming here a first end of the fibrous structure 200, and a third portion 250 also adjacent to the first portion 230 in the longitudinal direction DL and forming here a second end of the fibrous structure 200. In the central portion 230, all the layers of weft yarns are linked together by warp yarns of the plurality of warp layers by 3D or multi-layer weaving.

[0040] The fibrous structure 200 has a lower portion 210 intended to form the base of the ring sector, and an upper portion 220 connected to the lower portion 210 by the first portion 230. The second portion 240 comprises a base portion 241 present in the lower portion 210 of the fibrous structure 200 and a deployment portion 242 present in the upper portion of the structure adjacent to a first lateral end 231 of the first portion 230. Similarly, the third portion 250 comprises a base portion 251 present in the lower portion 210 of the fibrous structure 200 and a deployment portion 252 present in the upper portion of the structure adjacent to a second lateral end 232 of the first portion 230.

[0041] The deployment portions 242 and 252 are not connected respectively with the base portions 241 and 251 of the lower part 210, two unconnections 260 and 261 being provided during weaving in the fibrous structure at two opposite edges so as to leave the deployment portions 242 and 252 free. The two unconnections 260 and 261 each extend in the longitudinal direction DL respectively in the second and third parts 240 and 250 of the fibrous structure 200 from a unconnection bottom 2600, 2610 adjacent to the first part 230 of the fibrous structure. The unconnections 260 and 261 also extend in the transverse direction DT.

[0042] According to the invention, each deployment portion is separated into several independent plies by additional uncouplings, each ply comprising at least one layer of warp yarns of the first part of the fibrous structure and at least a layer of weft yarns, the warp yarns of the layer(s) of warp yarns being woven with the weft yarns of the layer(s) of weft yarns. When a ply comprises a layer of warp yarns and a layer of weft yarns, the warp and weft yarns are woven together in a two-dimensional weave.

[0043] When a ply comprises two layers of warp threads and / or two layers of weft threads, the warp and weft threads are woven together in a multi-layer weave.

[0044] When a ply comprises at least three layers of warp yarns and at least three layers of weft yarns, the warp yarns and the weft yarns are preferably woven together by 3D or multi-layer weaving.

[0045] There is therefore continuity of the warp threads in the first, second and third parts 230, 240 and 250 of the fibrous structure and in particular in the independent plies of the deployment portions ensuring good resistance of a fibrous reinforcement formed from the fibrous structure of the invention.

[0046] In the example described here, the deployment portion 242 of the second part 240 of the fibrous structure 200 is separated into four independent plies 2420, 2421, 2422 and 2423 by three uncouplings 270, 271 and 272 each extending in the longitudinal direction D1 in the second part 240 of the fibrous structure 200 respectively from the uncoupling bottoms 2700, 2710 and 2720 adjacent to the first part 230 of the fibrous structure. The uncouplings 270, 271 and 272 also extend in the transverse direction DT. The deployment portion 252 of the second part 250 of the fibrous structure 200 is separated into four independent plies 2520, 2521, 2522 and 2523 by three uncouplings 280, 281 and 282 each extending in the longitudinal direction DL in the third part 250 of the fibrous structure 200 respectively from the uncoupling bottoms 2800, 2810 and 2820 adjacent to the first part 230 of the fibrous structure.The delinks 280, 281 and 282 also extend in the transverse direction DT.

[0047] The fibrous structure according to the invention can in particular be produced by 3D or multi-layer weaving using an interlock, multi-satin, multi-plain or multi-twill weave.

[0048] By "multi-satin weave or fabric" is meant here a 3D or multi-layer weave with several layers of weft yarns whose basic weave of each layer is equivalent to a conventional satin weave but with certain points of the weave which bind the layers of weft yarns together. By "multi-plain weave or fabric" is meant here a 3D or multi-layer weave with several layers of weft yarns whose basic weave of each layer is equivalent to a conventional plain weave but with certain points of the weave which bind the layers of weft yarns together. By "multi-twill weave or fabric" is meant here a 3D weave with several layers of weft yarns whose basic weave of each layer is equivalent to a classic twill weave but with certain points of the weave that bind the layers of weft threads together.

[0049] By way of non-limiting example, the fibrous texture according to the invention can be produced by 3D weaving using a multi-satin weave as shown in [Fig.5].

[0050] [Fig.5] shows a multi-satin weave plan corresponding to a part of the first part 230 and the third part 250 of the fibrous structure 200. In this example, the fibrous structure 200 comprises twenty-eight layers of warp yarns CCi to CC28 in the first and third parts 230 and 250 and twenty-eight layers of weft yarns Cn to CT28 at least in the first part 230. With the exception of the warp yarns located on the surface of the fibrous structure and some warp yarns present in the independent plies 2520, 2521, 2522 and 2523, each warp yarn 203 is periodically deflected from its path above a weft layer to, alternately, grasp a weft yarn of this weft layer and grasp together a weft yarn of this weft layer and the weft yarn located in the same column of the lower adjacent weft layer.This creates classic single satin stitches PS 1 alternately with double satin stitches PS2 linking the threads of 2 adjacent weft layers, thus ensuring a connection between weft layers.

[0051] In [Fig.5]:

[0052] - twenty-eight layers of weft threads CTi to CT28 forming the first part 230 are linked together by twenty-eight warp threads 203 of the layers of warp threads Cci to C C28,

[0053] - ten layers of weft threads CTi9 to CT28 forming the base portion 251 are linked between them by ten warp threads 203 of the layers of warp threads CCi9 to CC28,

[0054] - four layers of weft threads CTi4 to CTi7 forming the ply 2520 are linked together by five warp threads CCi4 to CCi8,

[0055] - four layers of weft threads CT9 to CTi2 forming the ply 2521 are linked together by five warp threads Cc9 to CCb,

[0056] - three layers of weft threads CT5 to CT7 forming the ply 2522 are linked together by four warp threads CC5 to CC8,

[0057] - three layers of weft threads Cn to CT3 forming the ply 2523 are linked together by four warp threads CCi to Cc4.

[0058] The fact that the warp yarns CCi9 to CC28 do not extend into the layers of weft yarns CTi4 to CTi7 and that the warp yarns CCi4 to CCi8 do not extend into the layers of weft yarns CTi9 to CT28 ensures the unlinking 261 which separates the base portion 251 from the ply 2520. The fact that the warp yarns CCi4 to CCi8 do not extend into the layers of weft yarns CT9 to CTi2 and that the warp yarns Cc9 to CCb do not extend into the layers of weft yarns CTi4 to CTi7 ensures the unlinking 280 which separates the ply 2520 from the ply 2521. The fact that the warp yarns Cc9 to CCb do not extend into the layers of yarns of weft threads CT5 to CT7 and that the warp threads CC5 to CCs do not extend into the layers of weft threads CT9 to CTi2 ensures the unlinking 281 which separates the ply 2521 from the ply 2522. The fact that the warp threads CC5 to CCs do not extend into the layers of weft threads Cn to CT3 and that the warp threads CCi to CC4 do not extend into the layers of weft threads CT5 to CT7 ensures the unlinking 282 which separates the ply 2522 from the ply 2523.

[0059] In the example described here, the weft yarns of the weft yarn layers CT4, CT8, CTi3 and CTi8 are not woven into the third portion 250 of the fibrous structure 200 at the level of the delinks 261, 280, 281 and 282 respectively. The delinks can also be made without removing weft yarns, that is to say by having the same number of weft yarns between the portions 230 and 250.

[0060] The weave plan shown in [Fig.5] is repeated on several successive weave plans in the transverse direction DT by shifting the single satin stitches PSI and the double satin stitches PS2 along the longitudinal direction DL from one weave plan to another.

[0061] A similar multi-satin weave is used to make the base portion 241 and the independent plies 2420, 2421, 2422 and 2423 of the deployment portion 242 of the second part 240 of the fibrous structure.

[0062] The same weaving logic can be applied with interlock, multi-plain and multi-twill weaves to produce the fibrous structure 200. According to an alternative implementation, warp threads present in the first part 230 can be deflected upwards and downwards along the thickness direction EP in order to cross at the bottoms of the uncouplings, which makes it possible to reinforce said bottoms of uncouplings.

[0063] Furthermore, the independent plies of each deployment portion may be woven in a 3D or multi-layer weave different from the 3D or multi-layer weave of the rest of the fiber structure.

[0064] At the end of the weaving, the fibrous structure 200 illustrated in [Fig.4] is obtained.

[0065] [Fig.6] which shows a preform 300 obtained by shaping the structure fibrous 200, that is to say, after folding, on the one hand, independent folds 2420, 2421, 2422 and 2423 of the deployment portion 242 at 90° relative to the base portion 241 of the second part 240 and, on the other hand, independent folds 2520, 2521, 2522 and 2523 of the deployment portion 252 at 90° relative to the base portion 251 of the third part 250.

[0066] Thanks to the presence of a plurality of loose folds in each deployment portion, the superposition directions DS242 and DS232 of the weft threads of the weft columns respectively of the deployment portions 242 and 252 have an angular variation much lower than that obtained with single-piece deployment portions, that is to say not divided into a plurality of loose folds as shown in FIGS. 1 and 2. The weft columns in the deployment portions 242 and 252 have a shear angle α of less than 45° due to lower shear forces during folding of the deployment portions. The detachment of the fiber structure at the internal radii R1242 and R1252 and external radii RE242 and Re252 is thus significantly reduced, which allows better filling of the connecting radii by the fiber texture.

[0067] The offset of the weft thread columns in the deployment portions is further reduced, thus improving the infiltrability of the preform and better controlling the mechanical properties initially defined.

[0068] The example which has just been described concerns a fibrous structure with several deployment portions woven at the same time as base portions with a delinking between the deployment portions and the base portions. The invention naturally applies to fibrous structures having different architectures, in particular simpler ones. The weaving method of the invention can be applied to the weaving of a fibrous structure comprising, in a longitudinal direction, a base portion extended by a deployment portion intended to be folded during the shaping of the fibrous structure in order to form an L-shaped preform, for example in the case of the manufacture of a stiffener made of composite material.

[0069] The fiber preform 300 is then densified in order to form a composite material part, in the example described here a gas turbine ring sector. The densification of the fiber preform intended to form the fiber reinforcement of the part to be manufactured consists of filling the porosity of the preform, in all or part of the volume thereof, with the material constituting the matrix. This densification can be carried out in a manner known per se using the liquid process (CVL) or the gas process (CVI), or the ceramic charge injection process (Slurry Cast) or the silicon alloy impregnation process (MI or RMI) or even using a sequence of one or more of these processes.

[0070] The liquid process involves impregnating the preform with a liquid composition containing a precursor of the matrix material. The precursor is usually in the form of a polymer, such as a high-performance epoxy resin, optionally diluted in a solvent. The preform is placed in a sealable mold with a housing in the shape of the final molded blade. The mold is then closed and the liquid matrix precursor (e.g., a resin) is injected throughout the housing to impregnate the entire fiber portion of the preform.

[0071] The transformation of the precursor into a matrix, namely its polymerization, is carried out by heat treatment, generally by heating the mold, after elimination of any solvent and crosslinking of the polymer, the preform always being maintained in the mold having a shape corresponding to that of the part to be produced.

[0072] In the case of the formation of a carbon or ceramic matrix, the heat treatment consists of pyrolyzing the precursor to transform the matrix into a carbon or ceramic matrix depending on the precursor used and the pyrolysis conditions. For example, liquid ceramic precursors, in particular SiC or SiCN, may be resins of the polycarbosilane (PCS) or polytitanocarbosilane (PTCS) or polysilazane (PSZ) type, while liquid carbon precursors may be resins with a relatively high coke content, such as phenolic resins. Several consecutive cycles, from impregnation to heat treatment, may be carried out to achieve the desired degree of densification.

[0073] In the case in particular of the formation of an organic matrix, the densification of the fibrous preform can be carried out by the well-known transfer molding process known as RTM ("Resin Transfer Molding"). According to the RTM process, the fibrous preform is placed in a mold having the external shape of the part to be produced. A thermosetting resin is injected into the internal space of the mold which includes the fibrous preform. A pressure gradient is generally established in this internal space between the place where the resin is injected and the orifices for discharging the latter in order to control and optimize the impregnation of the preform by the resin.

[0074] Densification of the preform can also be carried out by polymer impregnation and pyrolysis (PIP), or by impregnation of a slip ("slurry cast"), containing for example SiC and organic binders, followed by infiltration with liquid silicon ("Melt infiltration").

[0075] The densification of the fiber preform can also be carried out, in a known manner, by gaseous means by chemical vapor infiltration of the matrix (CVI). The fiber preform corresponding to the fiber reinforcement of the part to be produced is placed in a furnace into which a reaction gas phase is admitted. The pressure and temperature prevailing in the furnace and the composition of the gas phase are chosen so as to allow the diffusion of the gas phase within the porosity of the preform to form the matrix by deposition, at the heart of the material in contact with the fibers, of a solid material resulting from a decomposition of a constituent of the gas phase or from a reaction between several constituents, unlike the pressure and temperature conditions specific to CVD ("Chemical Vapor Deposition") processes which lead exclusively to a deposition on the surface of the material.

[0076] The formation of a SiC matrix can be obtained with methyltrichlorosilane (MTS) giving SiC by decomposition of the MTS while a carbon matrix can be obtained with hydrocarbon gases such as methane and / or propane giving carbon by cracking.

[0077] A densification combining liquid and gaseous routes can also be used. to facilitate implementation, limit costs and manufacturing cycles while obtaining satisfactory characteristics for the intended use.

[0078] The densification processes described above make it possible to produce, from the fibrous structure of the invention, mainly parts made of organic matrix composite (OMC), carbon matrix composite (C / C) and ceramic matrix composite (CMC). Organic matrix composite (OMC), carbon matrix composite (C / C) and ceramic matrix composite (CMC) materials replace parts made of metallic material in certain parts of turbomachines. Their use contributes to optimizing aircraft performance, in particular by improving the efficiency of the turbomachine and reducing the overall mass of the turbomachine, significantly reducing emissions harmful to the environment (CO, CO2, NOx, etc.) as well as fuel consumption.

[0079] After densification, a part made of composite material is obtained.

[0080] The fibrous structure and its manufacturing method according to the present invention can in particular be used to produce turbine ring sectors, stiffeners, fixed or mobile turbomachine blades.

Claims

Claims

1. A method of manufacturing a fibrous structure (200) by weaving between a plurality of layers of warp yarns (203) and a plurality of layers of weft yarns (204), the warp yarns extending in a longitudinal direction (DL), the weft yarns extending in a transverse direction (DT), the weft yarns (204) being woven in a plurality of columns spaced apart from each other in the longitudinal direction, the weft yarns of each column of weft yarns being juxtaposed in the fibrous structure in a thickness direction (De) of said fibrous structure, the fibrous structure comprising a first portion (230) in which all the layers of weft yarns (CTi-CT2s) are linked together by warp yarns of the plurality of warp layers (CCi-CC2s) by three-dimensional or multi-layer weaving and at least a second portion (250) adjacent to the first portion in the longitudinal direction (DL),the second part comprising a base portion (251) and a deployment portion (252) separated from each other by a first uncoupling (261) extending in the longitudinal direction (DL) in the second part (250) of the fibrous structure (200) from a uncoupling bottom (2610) adjacent to the first part (230) of the fibrous structure, characterized in that said deployment portion (252) of said at least one second part (250) of the fibrous structure is separated in the thickness direction (DE) into at least first and second plies (2520, 2521) uncoupling by a second uncoupling (280) extending in the longitudinal direction (DL) in the second part (250) of the fibrous structure from a uncoupling bottom (2800) adjacent to the first part (230) of the fibrous structure and in that the first and second folds (2520,2521) each comprise at least one layer of warp yarns of the plurality of layers of warp yarns of the first part of the fibrous structure and at least one layer of weft yarns, the warp yarns of said at least one layer of warp yarns being woven with the weft yarns of said at least one layer of weft yarns.,

2. The method of claim 1, wherein the first and second plies (2520, 2521) each comprise at least three layers of warp yarns of the plurality of layers of warp yarns of the first portion of the fibrous structure and at least three layers of weft yarns, said at least first and second plies being woven by three-dimensional or multi-layer weaving of the warp yarns of said at least three layers of warp yarns with the weft yarns of said at least three layers of weft yarns.

3. The method of claim 2, wherein said at least first and second plies (2520, 2521) each comprise at most four layers of warp yarns of the plurality of layers of warp yarns of the first portion of the fibrous structure and four layers of weft yarns.

4. The method of claim 2 or 3, wherein said at least first and second plies (2520, 2521) are each woven in one of the following multi-layer weave patterns: interlock, multi-satin, multi-twill and multi-plain.

5. A method of manufacturing a part made of composite material comprising: - weaving a fibrous structure (200) in accordance with the weaving method according to any one of claims 1 to 4, - shaping the fibrous structure by folding said at least one deployment portion (252) so as to obtain a fibrous preform (300), - densifying the fibrous preform (300) by a matrix.

6. Use of the method for manufacturing a composite material part according to claim 5 for the manufacture of a turbine ring sector, a stiffener or a fixed or mobile turbomachine blade.

7. Fibrous structure (200) comprising a plurality of layers of warp yarns (203) and a plurality of layers of weft yarns (204), the warp yarns extending in a longitudinal direction (DL), the weft yarns extending in a transverse direction (DT), the fibrous structure comprising a plurality of columns of weft yarns spaced from each other in the longitudinal direction, the weft yarns of each column of weft yarns being juxtaposed in the fibrous structure in a thickness direction (DE) of said fibrous structure, the fibrous structure comprising a first portion (230) in which all the layers of weft yarns (CTi-CT2s) are linked together by warp yarns of the plurality of warp layers (C ci-CC2s) by three-dimensional or multi-layer weaving and at least a second portion (250) adjacent to the first portion in the longitudinal direction (DL),the second part comprising a base portion (251) and a deployment portion (252) separated from each other by a, first uncoupling (261) extending in the longitudinal direction (DL) in the second part (250) of the fibrous structure (200) from an uncoupling bottom (2610) adjacent to the first part (230) of the fibrous structure, characterized in that said deployment portion (252) of said at least one second part (250) of the fibrous structure is separated in the thickness direction (DE) into at least first and second plies (2520, 2521) uncoupled by a second uncoupling (280) extending in the longitudinal direction (DL) in the second part (250) of the fibrous structure from an uncoupling bottom (2800) adjacent to the first part (230) of the fibrous structure and in that the first and second plies (2520, 2521) each comprise at least one layer of warp yarns of the plurality of layers of warp threads of the first part of the fibrous structure and at least one layer of weft threads,the warp threads of said at least one layer of warp threads being woven with the weft threads of said at least one layer of weft threads.,

8. The structure of claim 7, wherein the first and second plies (2520, 2521) each comprise at least three layers of warp yarns of the plurality of layers of warp yarns of the first portion of the fibrous structure and at least three layers of weft yarns, said at least first and second plies being woven by three-dimensional or multi-layer weaving of the warp yarns of said at least three layers of warp yarns with the weft yarns of said at least three layers of weft yarns.

9. The structure of claim 8, wherein said at least first and second plies (2520, 2521) each comprise at most four layers of warp yarns of the plurality of layers of warp yarns of the first portion of the fibrous structure and four layers of weft yarns.

10. The structure of claim 8 or 9, wherein said at least first and second plies (2520, 2521) are each woven in one of the following multi-layer weave patterns: interlock, multi-satin, multi-twill, and multi-plain.

11. Part made of composite material comprising a fibrous reinforcement densified by a matrix characterized in that the fibrous reinforcement comprises a fibrous structure according to any one of claims 8 to 10.

12. A part according to claim 11, the part corresponding to a sector turbine ring, a stiffener or a fixed or mobile turbomachine blade.

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