Method for manufacturing a part of revolution made of composite material with locally optimized properties

Abstract

A manufacturing process for a part of revolution in composite material with locally optimized properties. A manufacturing process for a part of revolution (10) in variable thickness composite material for a gas turbine includes: - the creation by three-dimensional or multi-layer weaving of a fibrous texture (140) in the form of a strip, - the winding of the fibrous texture (140) in several superimposed layers (141, 142, 143, 144) on a mandrel (200) of profile corresponding to that of the housing to be manufactured, in order to obtain a fibrous preform of shape corresponding to that of the housing to be manufactured, - the densification of the fibrous preform by a matrix.During the winding of the fibrous texture (140) onto the mandrel, a textile strip (150) is placed at least between one or more adjacent turns of the fibrous texture, the textile strip (150) having a structure different from a three-dimensional weave and having a width less than the width of the fibrous texture (140) along an axial direction (DA). Figure for the abbreviation: Fig. 2.

Description

Title of the invention: Method for manufacturing a part of revolution in composite material with locally optimized properties Technical field

[0001] The present invention relates to the general field of the manufacture of rotating parts exposed to impacts and more particularly, but not exclusively, gas turbine fan casings for aeronautical engines. Prior art

[0002] In a gas turbine aircraft engine, the fan casing serves several functions. It defines the air inlet stream into the engine, supports an abradable material opposite the fan blade tips, supports a possible sound wave absorption structure for acoustic treatment at the engine inlet, and incorporates a retention shield. The retention shield provides a debris trap that retains debris, such as ingested objects or fragments of damaged blades, projected by centrifugation, to prevent them from passing through the casing and reaching other parts of the aircraft.

[0003] Previously made of metallic material, the casings, like the fan casing, are now made of composite material, that is to say from a fibrous preform densified by an organic matrix, which makes it possible to produce parts having a lower overall mass than these same parts when they are made of metallic material while having a mechanical resistance at least equivalent if not superior.

[0004] The manufacture of a fan casing made of organic matrix composite material is described in particular in document US 8,322,971. In the casing disclosed in document US 8,322,971, the retention shield is constituted by a portion of excess thickness obtained at the level of the fiber reinforcement of the casing which has a progressive thickness. The fiber reinforcement is obtained by winding a 3D woven fiber texture which has a portion of excess thickness capable of forming a retention shield. The casing thus obtained has at the level of its retention shield good mechanical properties both in terms of resistance to perforation (retention) and dynamic behavior.

[0005] However, the structural zones present outside the retention zone being thinner, they have less resistance to perforating or non-perforating impacts. These zones also have a sensitivity to vibratory stresses which can be problematic for the dynamic behavior of the casing. Indeed, their low thickness leads to a reduction in the natural frequencies of the fan casing and increases the risk of frequency crossover between one of its natural modes and the excitation frequencies from the wake of the fan blades opposite the casing in the engine operating range. The casing then enters into resonance when one of its natural frequencies crosses an excitation harmonic produced by the wake of the blades, which can lead to the casing being destroyed.

[0006] There are solutions in the prior art which aim to avoid the appearance of undesirable modes in a composite material casing. One solution, disclosed in particular in document US 2014 / 212273, consists of providing the composite material casing with added stiffeners. However, this solution results in a significant increase in the overall mass of the casing, in particular when it is a fan casing having a large diameter. It is also complicated to implement, in particular with regard to the fixing of the stiffeners which must be as reliable as possible.

[0007] Another solution, disclosed in document US 2017 / 266893, consists of stiffening a fan casing made of composite material by providing it with a portion having an omega profile. However, this solution results in a significant increase in the size and mass of the casing. Furthermore, due to its complex omega geometry, the production and installation of equipment (for example acoustic panels, abradable cartridges) on this type of casing proves to be tedious. Finally, the hollow formed by the omega portion must be filled with a material, which further penalizes the overall mass of the casing.

[0008] There is therefore a need for a solution enabling the mechanical properties of a composite material revolution part comprising a 3D woven fiber reinforcement to be locally optimized while minimizing the mass and / or manufacturing cost of the part. Statement of the invention

[0009] To this end, the invention proposes a method for manufacturing a composite material revolution part for a gas turbine, comprising:

[0010] - the production by three-dimensional weaving between a plurality of wires or strands of warp and a plurality of weft threads or strands of a fibrous texture with varying thickness in the form of a strip,

[0011] - winding the fibrous texture over several turns superimposed on a mandrel of profile corresponding to that of the part of revolution to be manufactured in order to obtain a fibrous preform of shape of revolution corresponding to that of the casing to be manufactured and extending in width in an axial direction and in thickness in a radial direction, the fibrous preform comprising a zone of greater thickness than the remainder of the fiber preform intended to form a retention zone in the revolution part,

[0012] - densification of the fiber preform by a matrix,

[0013] characterized in that, when winding the fibrous texture onto the mandrel, at at least one textile strip is placed at least between one or more adjacent turns of the fibrous texture, on the inner face of the first winding turn of the fibrous texture, or on the outer surface of the fibrous texture, each textile strip having a structure different from a three-dimensional weave, each textile strip having a width less than the width of the fibrous texture in the axial direction, each textile strip being located outside the part of greater thickness and delimiting a retention zone of the revolution part.

[0014] The method according to the invention makes it possible to locally optimize mechanical properties in the revolution part, without significantly increasing the overall mass of the part thanks to the use of one or more textile strips added with the 3D woven fiber texture intended to form the fiber reinforcement of the part. The cost and / or manufacturing time of a locally optimized revolution part are also well controlled because the local optimization of the mechanical properties of the part fits perfectly into the manufacturing process usually used. Indeed, only one or more textile strips are added to the 3D woven fiber texture during the formation of the fiber preform, which results in very few modifications to the usual manufacturing process.

[0015] According to a particular characteristic of the method of the invention, the width of said at least one textile strip in the axial direction is between 2% and 50% of the internal diameter of the fiber preform.

[0016] The method of the invention makes it possible to confer or locally optimize different mechanical properties, in particular depending on the architecture and the nature of the fibers used in the textile strip.

[0017] According to a first aspect of the invention, the textile strip is formed with fibers having an elongation at break greater than or equal to 1.7%.

[0018] According to a second aspect of the invention, the textile strip is made up of one or more unidirectional, two-dimensional layers or plies, multiaxial sheets or flat braids. The textile strip may in particular be made up of one or more two-dimensional layers having a satin-type weave.

[0019] According to a third aspect of the invention, the width of the textile strip in the axial direction corresponds to 10% of the width of the fiber preform.

[0020] According to a fourth aspect of the invention, the textile strip is formed with fibers having a Young's modulus of between 350 GPa and 500 GPa. The textile strip may consist of one or more unidirectional, bidirectional, or bidirectional layers or plies. ional or multiaxial sheets (NCF), the fibers of the textile strip being oriented in one or more directions different from the direction of the warp threads or strands and / or the direction of the weft threads or strands of the fiber texture. The fibers present in the textile strip may in particular be oriented at an angle of ± 45° relative to the direction of the warp and / or weft threads or strands of the fiber texture. The width of the textile strip in the axial direction may correspond to 15% of the width of the fiber preform.

[0021] The invention also relates to a revolution part made of a composite material manufactured in accordance with the method for manufacturing a revolution part made of a composite material of the invention. The revolution part may in particular correspond to a gas turbine fan casing or to a fan assembly comprising a fan casing and an outer shell of an intermediate casing in a single piece.

[0022] The invention also relates to a gas turbine aeronautical engine having a fan casing or a fan assembly according to the invention. Brief description of the drawings

[0023] [Fig-1] [Fig. 1] is a perspective and partial sectional view of an aeronautical engine equipped with a fan casing made of composite material in accordance with one embodiment of the invention,

[0024] [Fig.2] [Fig.2] is a sectional view along plane ILII of the casing of [Fig. 1],

[0025] [Fig.3] [Fig.3] is a schematic perspective view of a loom showing the weaving of a fibrous texture used for the formation of the fibrous reinforcement of the casing of figures 1 and 2,

[0026] [Fig.4] [Fig.4] is a perspective view showing the shaping of a fibrous texture and a textile strip intended to form the reinforcement of the fan casing of Figures 1 and 2,

[0027] [Fig.5] [Fig.5] is a schematic view showing the simultaneous winding of the fibrous structure and the textile strip of [Fig.4],

[0028] [Fig.6] [Fig.6] is a sectional view showing the profile of the fiber preform obtained after winding the fiber structure and the textile strip of Figures 4 and 5,

[0029] [Fig.7] [Fig.7] is a schematic view showing a tool for densifying the fiber preform of [Fig.6] with a matrix,

[0030] [Fig.8] [Fig.8] is a sectional view of a composite material fan assembly in accordance with one embodiment of the invention. Description of the embodiments

[0031] The invention applies generally to any part of revolution made of material gas turbine composite comprising a portion of excess thickness forming a retention zone or shield.

[0032] A method of manufacturing a rotating part of the invention is described below. applied, according to a first example, to a fan casing of an aeronautical gas turbine engine.

[0033] Such an engine, as shown very schematically by [Fig.l] comprises, from upstream to downstream in the direction of the gas flow E, a fan 1 arranged at the inlet of the engine, a compressor 2, a combustion chamber 3, a high-pressure turbine 4 and a low-pressure turbine 5.

[0034] The engine is housed inside a casing comprising several parts corresponding to different elements of the engine. Thus, the fan 1 is surrounded by a fan casing 10 having a shape of revolution.

[0035] [Fig. 2] shows the profile (in axial section) of the fan casing 10 which is here made of organic matrix composite material, that is to say from a fiber reinforcement for example of carbon, glass, aramid or ceramic, densified by a polymer matrix, for example epoxide, bismaleimide or polyimide. The manufacture of such a casing is described in particular in document US 8,322,971. The internal surface 11 of the casing defines the air inlet stream of the engine.

[0036] The casing 10 extends in width in an axial direction DA between its upstream and downstream ends (from left to right in [Fig.2]) which are here provided with external flanges 14, 15 to allow its mounting and its connection with other elements. The casing 10 extends in length in a circumferential direction Dc. Between its upstream and downstream ends, the casing 10 has, in a radial direction DR, a variable thickness in the axial direction DA, a part 16 of the casing having a greater thickness than the end parts by gradually connecting to it.Part 16 extends on either side of the location of the fan, upstream and downstream, in order to form a retention zone capable of retaining debris, particles or objects ingested at the engine inlet, or originating from damage to fan blades, and projected radially by rotation of the fan, to prevent them from passing through the casing and damaging other parts of the aircraft.

[0037] The fibrous reinforcement is formed by winding onto a mandrel a fibrous texture produced by three-dimensional weaving with evolving thickness, the mandrel having a profile corresponding to that of the casing to be produced. Advantageously, the fibrous reinforcement constitutes a complete tubular fibrous preform of the casing 10 forming a single piece.

[0038] According to the invention, the casing 10 comprises a local reinforcement portion 12 present outside the thicker part 16 forming a retention zone. The revolution part according to the invention may comprise several local portions of reinforcement present upstream and / or downstream of the thicker part 16.

[0039] The fibrous reinforcement of the casing 10 is made up of a plurality of superimposed layers 141 to 144 of a fibrous texture 140 in the form of a strip having a three-dimensional or multi-layer weave, each layer 141 to 144 corresponding to one winding turn of the fibrous texture 140 (in [Fig. 2] the layers 141 to 144 are densified by a matrix). In addition, a textile strip 150 is interposed between two adjacent layers of the fibrous texture, the textile strip 150 having a width 1 no less than the width 1140 of the fibrous texture 140 ([Fig. 4]). In the example described here, three layers 151 to 153 of textile strip 150 are interposed between the superimposed layers 141 to 144 of the fibrous texture 140, each layer 151 to 153 corresponding to one winding turn of the textile strip 150.In general, the textile strip making it possible to form a local reinforcement portion can be interposed between two or more superimposed layers of fibrous texture, each corresponding to a winding turn of said fibrous texture. According to an alternative embodiment, a textile strip making it possible to form a local reinforcement portion can also be present on the internal face of the first winding turn and / or on the external face of the last winding turn of the fibrous texture of the fibrous reinforcement.

[0040] As described in detail below, by adding a textile strip to the fiber reinforcement of the part, it is possible to locally give the part particular mechanical properties.

[0041] A method of manufacturing the fan casing 10 is now described.

[0042] As shown in [Fig. 3], a fibrous texture 140 is produced in a known manner by weaving using a jacquard type loom 60 on which a bundle of warp threads or strands 70 has been arranged in a plurality of layers, the warp threads being linked by weft threads or strands 80. The fibrous texture is produced by three-dimensional weaving.

[0043] 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.

[0044] The production of the fibrous texture by 3D weaving makes it possible to obtain a connection between the layers, thus providing good mechanical strength of the fibrous structure and the composite material part obtained, in a single textile operation.

[0045] As illustrated in Figures 3 and 4, the fibrous texture 140 has a strip shape which extends lengthwise in a direction X ([Fig.3]) corresponding to the direction of travel of the warp threads or strands 70 and widthwise or transversely in a direction Y ([Fig.3]) corresponding to the direction of travel of the weft threads or strands 80. As explained below, the fibrous reinforcement of the revolution part, here the casing 10, is formed by the fibrous texture 140 which is shaped by winding on itself. Consequently, in the fibrous reinforcement of the final part, the warp threads or strands extend in the circumferential direction Dc (Figures 1, 3 and 6) while the weft threads or strands extend in the axial direction DA (Figures 1, 3 and 6).

[0046] The fibrous structure may in particular be woven from carbon, ceramic such as silicon carbide, glass, or aramid fiber threads.

[0047] The textile strip 150 is produced independently. It has a textile structure different from a three-dimensional weave. The textile strip may in particular, but not exclusively, be formed by one or more unidirectional (UD), two-dimensional (2D) layers or plies with fibers oriented at 0° / 90° or +45° / -45° or by one or more multiaxial sheets (“Non Crimp Fabric” in English or NCF) which is a textile fabric which generally has several layers of non-woven unidirectional fibers oriented in different directions linked by a fine knitting yarn.

[0048] Depending on the mechanical properties that we wish to confer locally, we choose a specific textile structure and one or more types of fibers.

[0049] Generally, the width of the textile strip along the axial direction DA is between 2% and 50% of the width of the fiber preform.

[0050] As illustrated in [Fig. 4], a fiber preform is formed by winding the fiber texture 140 produced by three-dimensional weaving onto a mandrel 200, the mandrel having a profile corresponding to that of the casing to be produced. According to the invention, a textile strip 150 is wound simultaneously with the fiber texture 140, the strip 150 being positioned above the first layer 141 of the texture 140 wound onto the mandrel 200 so as to interpose a layer of textile strip 150 of smaller width between two adjacent layers of fiber texture of larger width corresponding to two turns of winding of the fiber texture 140. The strip 150 is positioned at a location on the fiber texture 140 corresponding to the axial zone of the local reinforcement portion to be formed in the casing.

[0051] Advantageously, the fiber preform constitutes a complete tubular fiber reinforcement of the casing 100 forming a single piece with a portion of excess thickness corresponding to the retention zone of the casing and at least one portion in which a textile strip is added in order to form a local reinforcement portion.

[0052] For this purpose, the mandrel 200 has an external surface 201 whose profile corresponds to the internal surface of the casing to be produced. By being wound on the mandrel 200, the fibrous texture 140 matches the profile thereof. The mandrel 200 also comprises two flanges 220 and 230 to form parts of fibrous preform corresponding to the flanges 14 and 15 of the casing 100.

[0053] When forming the fiber preform by winding, the fiber texture 140 and the textile strip 150 are drawn from drums 60 and 70 respectively on which they are stored as illustrated in [Fig.5].

[0054] [Fig. 6] shows a sectional view of the fiber preform 300 obtained after winding the fiber texture 140 and the textile strip 150 in several layers on the mandrel 200. The number of layers or turns depends on the desired thickness and the thickness of the fiber texture. It is preferably at least equal to two. In the example described here, the preform 300 comprises four layers 141 to 144 of fiber texture 140 and three layers 151 to 153 of textile strip 150 interposed respectively between the adjacent layers 141 and 142, 142 and 143, and 143 and 144.

[0055] A fiber preform 300 is obtained with a reinforcing preform portion 310 formed by the interposition of the layers 151 to 153 of the textile strip 150 between the superimposed layers 141 to 144 of the fiber texture 140. The fiber preform 300 also comprises a thicker preform portion 320 corresponding to the thicker portion 16 forming a retention zone of the casing 10.

[0056] As indicated above, the zone or axial extent on which it is desired to confer particular mechanical properties is determined by the width l150 of the textile strip 150 (figures 4 and 6).

[0057] When it is desired to form a local reinforcement portion having improved non-perforating impact resistance, a textile strip is preferably used comprising fibers having a high strain at break, i.e., fibers having an elongation at break greater than or equal to 1.7%, such as, for example, carbon fibers which have an elongation at break greater than 2% or glass fibers which generally have an elongation at break greater than 5%. The textile strip may consist of one or more unidirectional (UD), two-dimensional (2D), multiaxial plies (NCF) or flat braid layers or plies. Structures which are easily deformable, i.e., which do not exhibit sagging, such as UD layers or multiaxial plies, are preferably used for the textile strip. In the case of 2D layers, weave weaves having low sagging, such as satin weaves, will be used.The fibers may be oriented in the same direction as the warp and / or weft yarns of the fiber texture 140 or in a different direction.

[0058] The width of the textile strip has a width preferably corresponding to sens- possibly 10% of the width of the preform in the axial direction DA.

[0059] When it is desired to form a local reinforcement portion having improved stiffness, a textile strip is preferably used comprising fibers having a Young's modulus of between 350 GPa and 500 GPa, such as, for example, Torayca® carbon fibers type M40 or M46J marketed by the company Toray or Tenax™ carbon fibers type UMS40 or UMS45 marketed by the company Teijin. The textile strip may consist of one or more unidirectional (UD), two-dimensional (2D) or multiaxial (NCF) layers or plies.The fibers of the textile strip may be oriented according to the direction(s) in which it is desired to improve or increase the stiffness, in particular in directions different from the direction of the warp threads or strands in the fiber reinforcement of the revolution part, i.e. in a direction different from the circumferential direction Dc and / or the direction of the weft threads or strands in the fiber reinforcement of the revolution part, i.e. in a direction different from the axial direction DA. The fibers of the textile strip may in particular be oriented at an angle of 30°, 45° or 60° relative to the direction of the warp and / or weft threads or strands of the fiber reinforcement of the part corresponding to the fiber preform.In the case where it is desired to orient the fibers of the fibrous strip in a single direction different from that of the warp and / or weft yarns or strands of the fiber reinforcement of the part, it is possible to use UD layers oriented according to the chosen angle. In the case where it is desired to orient the fibers of the fibrous strip in several directions different from that of the warp and / or weft yarns or strands, it is possible to use 2D layers or a multiaxial sheet (NFC) (2 superimposed UD layers) to form a textile strip having two different fiber directions relative to the direction of the warp and / or weft yarns or strands of the fiber reinforcement of the part, for example according to an orientation ±45°.To form a textile strip having more than two different fiber directions relative to the direction of the warp and / or weft yarns or strands of the fiber reinforcement of the part, a multiaxial sheet (n superimposed UD layers) can be used, each UD layer of the sheet being oriented in a specific direction or angle. An orientation of the fibers of the textile strip at ± 45° relative to the direction of the warp and / or weft yarns or strands of the fiber reinforcement of the part makes it possible to reinforce the shear / torsion resistance of the part.

[0060] The width of the textile strip has a width preferably corresponding to substantially 15% of the width of the preform in the axial direction DA.

[0061] The fiber preform 300 is then densified using a matrix.

[0062] The densification of the fiber preform consists of filling the porosity of the preform, in all or part of its volume, by the material constituting the matrix.

[0063] The matrix can be obtained in a manner known per se using the liquid method.

[0064] The liquid method consists of impregnating the preform with 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, possibly diluted in a solvent. The fibrous preform is placed in a mold that can be closed in a sealed manner with a housing having the shape of the final molded part. As illustrated in [Fig. 7], the fibrous preform 300 is here placed between a plurality of sectors 240 forming a counter-mold and the mandrel 200 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 into the entire housing to impregnate the entire fibrous part of the preform.

[0065] 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 still being 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, a high-performance epoxy resin available commercially, or from liquid precursors of carbon or ceramic matrices.

[0066] In the case of the formation of a carbon or ceramic matrix, 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 may be resins with a relatively high coke content, such as phenolic resins, while liquid ceramic precursors, in particular SiC, may be resins of the polycarbosilane (PCS) or polytitanocarbosilane (PTCS) or poly-silazane (PSZ) type. Several consecutive cycles, from impregnation to heat treatment, may be carried out to achieve the desired degree of densification.

[0067] According to one aspect of the invention, the densification of the fiber preform can be carried out by the well-known transfer molding process known as 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 mandrel 200 and the counter-molds 240 and which comprises the fiber 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.

[0068] The resin used may 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.

[0069] After injection and polymerization, the part is demolded. Finally, the part is trimmed to remove excess resin and the chamfers are machined to obtain the casing 10 illustrated in Figures 1 and 2.

[0070] The method of the invention is not limited to the manufacture of fan casings. Indeed, the method of the invention can also be used for the manufacture of a fan assembly combining in a single piece a fan casing and an outer shell of the intermediate casing,

[0071] [Fig. 8] shows the profile (in axial section) of a fan assembly 50 comprising upstream a fan casing 20 and downstream an intermediate casing outer shroud 30, the fan assembly being made in a single piece made of organic matrix composite material, i.e. from a fiber reinforcement densified by a polymer matrix as already described above for the fan casing 10. The manufacture of such a casing assembly is described in particular in document FR 2 968 364.

[0072] The fan assembly 50 extends in width in an axial direction DA between its upstream and downstream ends (from left to right in [Fig. 2]) which are here provided with external flanges 24, 35 to allow its mounting and connection with other elements. The fan assembly 50 extends in length in a circumferential direction Dc. The fan assembly 50 comprises a fan casing 20 extended downstream by an intermediate casing outer shroud 30. As well known per se, the fan casing surrounds the moving fan blades (not shown in [Fig. 8]) while the intermediate casing outer shroud is fixed to fan guide vanes generally called OGV (for "Outlet Guide Vane" in English (not shown in [Fig. 8]).

[0073] The fan casing 20 has, in a radial direction DR, a variable thickness in the axial direction DA, a portion 26 of the fan casing having a greater thickness than the end portions by progressively connecting to it. The portion 26 extends on either side of the location of the fan, upstream and downstream, in order to form a retention zone capable of retaining debris, particles or objects ingested at the engine inlet, or originating from damage fan blades, and projected radially by rotation of the fan, to prevent them from passing through the casing and damaging other parts of the aircraft.

[0074] The fibrous reinforcement of the blower assembly is formed by winding onto a mandrel a fibrous texture produced by three-dimensional weaving with evolving thickness, the mandrel having a profile corresponding to that of the assembly to be produced. Advantageously, the fibrous reinforcement constitutes a complete tubular fibrous preform of the blower assembly 50 forming a single piece.

[0075] In the example described here and in accordance with the invention, the outer shell of the intermediate casing 30 comprises two local reinforcement portions 32 and 33 present outside the thicker part 26 of the fan casing. However, it is not outside the scope of the invention when the outer shell of the intermediate casing comprises only one local reinforcement portion.

[0076] The fiber reinforcement of the fan assembly 50 consists of a plurality of superimposed layers 541 to 544 of a fiber texture 540 in the form of a strip having a three-dimensional or multi-layer weave, each layer 541 to 544 corresponding to one winding turn of the fiber texture 540 (in [Fig. 8] the layers 541 to 544 are densified by a matrix). In addition, first and second textile strips 550 and 560 are interposed between two adjacent layers of the fiber texture at positions offset along the axial direction DA in the fiber reinforcement portion of the intermediate casing shell. The textile strips 550 and 560 each have a width 1550, 1560 less than the width of the fiber texture 540.In the example described here, three layers 551 to 553 of textile strip 550 and three layers 561 to 563 of textile strip 560 are interposed between the superimposed layers 541 to 544 of the fibrous texture 540, each layer 551 to 553, respectively 561 to 563, corresponding to one winding turn of the textile strip 550, respectively of the textile strip 560. In general, each textile strip making it possible to form a local reinforcement portion can be interposed between two or more superimposed layers of fibrous texture each corresponding to one winding turn of said fibrous texture. According to an alternative embodiment, a textile strip making it possible to form a local reinforcement portion can also be present on the internal face of the first winding turn and / or on the external face of the last winding turn of the fibrous texture of the fibrous reinforcement.

[0077] The blower assembly can be manufactured in the same way as that already described previously for the blower casing 10 and will not be described again here for the sake of simplification. In addition, the different types of fibers as well as the textile structures (UD, 2D, multiaxial sheets, etc. with fiber orientations in one or more determined directions) described previously can also be used here for the blower assembly 50. The width of the textile strip(s) used to form one or more reinforcement portions in the outer shell of the intermediate casing is preferably substantially between 10% and 15% of the width of the fiber reinforcement or preform of the outer shell of the intermediate casing in the axial direction DA.

[0078] In addition to conferring or improving the mechanical properties of the fan assembly 50 as already described above for the fan casing 10, the local reinforcement portions 32 and 33 can be used for fixing the outer ends of the fan guide vanes, for example by means of a screw-nut type fixing member.

Claims

Claims

1. Method for manufacturing a composite material revolution part (100) for a gas turbine, comprising: - producing by three-dimensional weaving between a plurality of warp threads or strands and a plurality of weft threads or strands a fibrous texture (140) with varying thickness in the form of a strip, - winding the fibrous texture (140) over several superimposed turns (141, 142, 143, 144) on a mandrel (200) with a profile corresponding to that of the casing to be manufactured in order to obtain a fibrous preform (300) with a revolution shape corresponding to that of the revolution part to be manufactured and extending in width in an axial direction (DA) and in thickness in a radial direction (DR), the fibrous preform (300) comprising a zone of greater thickness (320) than the rest of the fibrous preform intended to form a retention zone (16) in the revolution part (10),- densifying the fibrous preform (300) by a matrix, characterized in that, when winding the fibrous texture (140) onto the mandrel (200), at least one textile strip (150) is placed at least between one or more adjacent turns of the fibrous texture, on the inner face of the first winding turn of the fibrous texture, or on the outer surface of the fibrous texture, each textile strip (150) having a structure different from a three-dimensional weave, each textile strip having a width less than the width of the fibrous texture (140) in the axial direction, each textile strip being located outside the part of greater thickness and delimiting a retention zone of the part of revolution.,

2. Method according to claim 1, wherein the width (li50) of said at least one textile strip (150) in the axial direction is between 2% and 50% of the width of the fibrous preform (300).

3. The method of claim 2, wherein the textile web is formed with fibers having an elongation at break greater than or equal to 1.7%.

4. / V. A method according to claim 2 or 3, wherein said at least one textile strip consists of one or more unidirectional, two-dimensional layers or plies of multiaxial webs or flat braids.

5. A method according to claim 4, wherein said at least one textile strip is made of one or more two-dimensional layers featuring a satin-type weave.

6. Method according to any one of claims 2 to 5, wherein the width (1150) of said at least one textile strip (150) in the axial direction corresponds to 10% of the width of the fibrous preform (300).

7. The method of claim 2, wherein said at least one textile strip is formed with fibers having a Young's modulus of between 350 GPa and 500 GPa.

8. Method according to claim 7, wherein said at least one textile strip consists of one or more unidirectional, two-dimensional or multiaxial layers or plies (NCF), the fibers of said at least one textile strip being oriented in one or more directions different from the direction of the warp threads or strands and / or the direction of the weft threads or strands of the fiber texture.

9. Method according to claim 7, in which the fibers present in said at least one textile strip are oriented at an angle of ± 45° relative to the direction of the warp and / or weft threads or strands of the fibrous texture.

10. Method according to any one of claims 7 to 9, wherein the width (1150) of said at least one textile strip (150) in the axial direction corresponds to 15% of the width of the fibrous preform (300).

11. Method according to any one of claims 1 to 10 in which the part of revolution corresponds to a fan casing.

12. Method according to any one of claims 1 to 10 in which the part of revolution corresponds to a fan casing and intermediate casing shell assembly in a single piece.

13. A composite material revolution part manufactured in accordance with the method according to any one of claims 1 to 10.

14. A revolution part according to claim 13, said revolution part corresponding to a gas turbine fan casing.

15. A revolution part according to claim 13, said revolution part corresponding to a fan assembly comprising a fan casing and an intermediate casing outer shell in one piece.

16. A gas turbine aircraft engine having a casing (10) according to claim 14 or a fan assembly according to claim 15.

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