Blade made of composite material including damping fibers

Abstract

Composite material turbine blade comprising damping fibers. The invention relates to a fibrous texture (200) intended to form the fibrous reinforcement of a turbomachine blade made of composite material, the fibrous texture (200) being obtained by three-dimensional weaving between a plurality of warp yarns (210) extending along a longitudinal direction and a plurality of weft yarns (220) extending along a transverse direction, a portion of the yarns (221) being made of a first material, the fibrous texture (200) being characterized in that another portion of the yarns (222) are made of a second damping material different from the first material, the second material being a linear polyamide, a polyester, a polyethylene, or a polyazole. Figure for the abstract: Fig. 3

Description

Title of the invention: Blade made of composite material comprising damping fibers Technical field

[0001] The present invention relates to the manufacture of blades from composite material, and more particularly to the manufacture of blades from organic matrix composite material (OMC). Prior art

[0002] The production of blades from organic matrix composite (OMC) material is well known. Organic matrix composite (OMC) materials are lighter than most metals while retaining good mechanical properties. The efficiency of the turbomachine is improved, which allows a reduction in fuel consumption.

[0003] The fiber reinforcement of the turbomachine blades is formed by a fiber preform. The fiber preform is conventionally obtained by weaving a plurality of fibers, for example by three-dimensional weaving. The fibers are conventionally made of carbon or ceramic. A resin is then injected into the fiber preform and then treated, so as to form an organic matrix in the porosities of the fiber preform to obtain the blade made of composite material.

[0004] Turbomachine blades are subjected to significant vibrations during operation, which can deform the blades or even lead to their rupture. In order to dampen these vibrations, it is known to place elastomer pads between the blades and the surrounding parts of the turbomachine. Indeed, the use of such pads allows mechanical damping without modifying the design of the blade.

[0005] However, elastomer pads are difficult to size to obtain sufficient mechanical damping. In addition, elastomer pads gradually wear out, requiring the scheduling of regular maintenance operations to replace them. Statement of the invention

[0006] The aim of the present invention is to propose a blade made of composite material integrating a damping system.

[0007] To this end, the invention proposes a fibrous texture intended to form the fibrous reinforcement of a turbomachine blade made of composite material, the fibrous texture being obtained by three-dimensional weaving between a plurality of warp threads extending in a longitudinal direction and a plurality of weft threads extending in a transverse direction, a portion of the threads being made of a first material, the fibrous texture being characterized in that another part of the threads is made of a second damping material different from the first material, the second material being a linear polyamide, a polyester, a polyethylene or a polyazole.

[0008] Thus, by integrating fibers fulfilling a damping function during the weaving of the fiber preform, the final blade has intrinsic damping characteristics. It is thus no longer necessary to use additional parts, for example elastomer pads, to dampen the vibrations to which the blade is subjected. Since the damping fibers are present inside the blade, they are not directly subjected to the external environment. Thus, the damping function of the blade degrades very little over time. Finally, the use of such damping fibers also makes it possible to improve the resistance of the blade to impacts and shocks, and to improve its resistance during maintenance operations.

[0009] According to a particular embodiment of the invention, the second material is poly(p-phenylene-2,6-benzobisoxazole).

[0010] Poly(p-phenylene-2,6-benzobisoxazole) is known under the trade name Zylon®. Zylon® is particularly interesting in that it can have an elastic modulus similar to the elastic modulus of carbon. Thus, the introduction of Zylon® fibers during weaving will not result in a reduction in the stiffness of the blade. Furthermore, the introduction of Zylon® fibers during weaving does not add constraints for the rest of the blade manufacturing process. Indeed, Zylon® fibers withstand very well the processes of densification of the fiber preform, for example the injection of resin, but also react well during machining operations or during surface treatments.

[0011] The invention then proposes a fibrous texture intended to form the fibrous reinforcement of a turbomachine blade made of composite material, the fibrous preform being obtained by three-dimensional weaving between a plurality of warp threads extending in a longitudinal direction and a plurality of weft threads extending in a transverse direction, a portion of the threads being made of a first material, the fibrous preform being characterized in that another portion of the threads are made of a second damping material different from the first material, the second material being poly(p-phenylene-2,6-benzobisoxazole).

[0012] According to another particular embodiment of the invention, the first material is carbon.

[0013] According to another particular embodiment of the invention, the threads made from the second material are weft threads.

[0014] According to another particular embodiment of the invention, the threads made from the second material are warp threads.

[0015] According to another particular embodiment of the invention, the fibrous texture comprises, along the longitudinal direction, at least one root portion intended to form the fibrous reinforcement of the root of the blade to be produced and an aerodynamic profile portion intended to form the fibrous reinforcement of the aerodynamic profile of the blade to be produced, the aerodynamic profile portion of the fibrous texture comprising, along a vertical direction perpendicular to the transverse and longitudinal directions, a first surface portion, a core portion and a second surface portion, the threads made of second damping material being present in the first and second surface portions.

[0016] Preferably, the core portion is free of wires made of a second damping material.

[0017] Thus, the damping threads made of second material are mainly located close to the surfaces of the fibrous texture, which are the areas requiring the most damping.

[0018] According to a particular embodiment of the invention, the thickness of the core portion in the vertical direction represents at least 40% of the thickness of the aerodynamic profile portion in the vertical direction.

[0019] The invention also relates to a fiber preform obtained by shaping the fiber texture as described above.

[0020] Thus, the invention proposes a fiber preform intended to form the fiber reinforcement of a turbomachine blade made of composite material, the fiber texture being obtained by three-dimensional weaving between a plurality of warp threads extending in a longitudinal direction and a plurality of weft threads extending in a transverse direction, a portion of the threads being made of a first material, the fiber preform being characterized in that another portion of the threads are made of a second damping material different from the first material, the second material being a linear polyamide, a polyester, a polyethylene or a polyazole.

[0021] According to a particular embodiment of the invention, the preform is intended to form the fibrous reinforcement of a fan blade.

[0022] The invention further relates to a turbomachine blade made of composite material, the fiber reinforcement of which comprises the fiber preform as described previously.

[0023] According to a particular embodiment of the invention, the blade is made of organic matrix composite material.

[0024] The invention finally proposes a method for manufacturing a turbomachine blade made of organic matrix composite material comprising:

[0025] - the production of a fibrous texture as described previously,

[0026] - shaping the fibrous texture so as to obtain a fibrous preform,

[0027] - injecting a matrix precursor resin into the fiber preform,

[0028] - the treatment of the resin in order to form the organic matrix in the porosities of the fiber preform so as to obtain the blade in composite material Brief description of the drawings

[0029] [Fig-1] [Fig. 1] is a schematic perspective view of a Jacquard type loom in neutral position.

[0030] [Fig.2] [Fig.2] is a schematic perspective view of the loom of [Fig.l] with a shed creation.

[0031] [Fig.3] [Fig.3] is a schematic perspective view of a fibrous texture according to the invention.

[0032] [Fig.4] [Fig.4] is an exploded perspective schematic view showing an injection tool and the placement of a fiber preform therein, the fiber preform being obtained by shaping the texture of [Fig.3].

[0033] [Fig.5] [Fig.5] is a schematic perspective view showing the injection tooling of [Fig.4] closed. Description of the embodiments

[0034] The invention applies generally to the manufacture of blades from a fiber preform. The fiber preform is obtained by shaping a fiber texture produced by three-dimensional weaving. By "three-dimensional weaving" is meant here a weaving method by which at least some of the warp threads bind weft threads over several weft layers. It is considered that a fiber texture produced by three-dimensional weaving may comprise another type of weaving on its surface, for example two-dimensional weaving, in order to improve its surface condition.

[0035] The fibrous texture may, for example, have a three-dimensional weave of the interlock or multi-satin type. Different three-dimensional weaving methods that can be used to form the fibrous texture are described in document WO 2006 / 136755.

[0036] Figures 1 and 2 illustrate a weaving loom 100 for producing the fibrous texture 200 intended to form the fibrous preform. The weaving loom 100 makes it possible to obtain the fibrous texture 200 by weaving a plurality of warp threads 210 with a plurality of weft threads 220. The fibrous texture 200 extends in length in a horizontal direction DH and in thickness in a vertical direction Dv on the weaving loom 100.

[0037] The loom is equipped with a Jacquard mechanism 110 supported by a superstructure not shown in Figures 1 and 2. The loom 100 also comprises a harness 120 comprising control or heddle threads 121, each control thread 121 being connected at one end to a control element 111 of the Jacquard mechanism 110. In the example illustrated in Figures 1 and 2, each control thread 121 is connected at one end to a control hook 111 of the Jacquard mechanism 110 and at the other end to a return spring 112 fixed to the frame 113 of the loom 100. The control threads 121 extend in the vertical direction Dv. The harness 120 may also include a tying board 122.

[0038] Each control thread 121 comprises an eyelet 121a crossed by a warp thread 210. Each warp thread 210 of the loom 100 passes through an eyelet 121a of the harness 120. The warp threads 210 are organized at the harness 120 of the loom 100 in a plurality of horizontal layers and vertical columns which are manipulated by the loom 100 to allow the insertion of weft threads 220 according to the weaving pattern(s) programmed in the loom 100. The weft threads 220 are inserted between the warp threads 210 by column extending in the vertical direction Dv. In order to allow the introduction of each column of weft threads 220 during the weaving of the texture 200, a warp thread call system 210 (not shown in figures 1 and 2) is associated with the loom 100.This system, placed downstream of the weaving loom 100, has the role of holding all the warp threads 210 together in a clamping device and of allowing the warp threads 210 to advance by a determined distance in the horizontal direction DH after the insertion of each weft column 220.

[0039] The terms “upstream” and “downstream” are defined here according to the direction of advance of the warp threads 210 in the loom 100, that is to say according to the weaving direction, along the horizontal direction DH.

[0040] The control threads 121 and their associated eyelet 121a are able to move in the vertical direction Dv. In [Fig.l], all the control threads 121 are in a neutral position in which no traction is exerted by the Jacquard mechanism 110. In this configuration, no shed is created and all the warp threads 210 extend parallel to the horizontal direction DH.

[0041] When creating a shed, as illustrated in [Fig. 2], a portion of the control threads 121 are subjected to tensile forces exerted by the control hooks 111. In this configuration, the control threads make it possible to raise or lower warp threads, so as to separate an upper layer of warp threads from a lower layer of warp threads by an opening, called a shed.

[0042] The loom 100 also comprises a lance 130, present downstream of the control threads 121. The lance 130 is composed of a rod 131, a first end of which is connected to an actuation system (not shown in FIGS. 1 and 2) making it possible to drive the rod 131 with a back-and-forth movement. The other end of the rod 131 is provided with a gripper 132 which, after having passed through the shed during the outward journey of the rod 131, can come and grasp a weft thread 220 stored on a bobbin 140 to unwind it in the shed during the return journey of the rod 131. The weft thread 220 as well placed inside the shed is then cut in the vicinity of the bobbin 140 by a cutting tool 150 and released at its other end by the clamp 132. A comb 160 present upstream of the lance 130 and downstream of the harness 120 in its rest position is then folded down in order to pack the weft thread(s) 220 introduced into the shed. The lance 130 is then ready to pick up a new weft thread 220 from the bobbin 140 and place it either in the same shed or in a different shed depending on the defined weave. The fibrous texture 200 is thus gradually formed, having a three-dimensional weave between the warp threads 210 and the weft threads 220.

[0043] Preferably, the weaving loom 100 further comprises a guiding device 170 for the fibrous texture 200 present downstream of the control threads 121 and the lance 130. Such a guiding device 170 is described in particular in the document FR 3 074 195 A1. In the example described here, the guiding device 170 comprises a lower jaw 171 and an upper jaw 172 each connected to an actuating means (not shown in FIGS. 1 and 2) which is capable on the one hand of holding the fibrous texture 200 and on the other hand of moving the jaws 171 and 172 in the vertical direction Dv. It is thus easier to create sheds at the level of the lower or upper layers of warp threads 210, even with a large number of layers of warp threads 210 superimposed in the vertical direction Dv.

[0044] An example of a fibrous texture 200 thus obtained is illustrated in [Fig. 3]. The fibrous texture 200 may comprise at least a root portion 201 and an aerodynamic profile portion 203. The root portion 201 of the fibrous texture 200 is intended to form the fibrous reinforcement of the root of the blade to be obtained. The aerodynamic profile portion 203 of the fibrous texture 200 is intended to form the fibrous reinforcement of the aerodynamic profile of the blade to be obtained. The fibrous texture 200 may also comprise a transition portion 202 between the root portion 201 and the aerodynamic profile portion 203. The transition portion 202 of the fibrous texture 200 is intended to form the fibrous reinforcement between the root and the aerodynamic profile of the blade to be obtained.

[0045] The fibrous texture 200 extends in the horizontal direction DH between a lower edge 200a and an upper edge 200b. The horizontal direction DH will correspond, after shaping the fibrous texture 200, to the span direction of the blade to be obtained. The fibrous texture 200 extends in the vertical direction Dv between a first face 200c and a second face 200d. The first face 200c of the fibrous texture 200 is intended to form the fibrous reinforcement of the intrados face of the blade to be obtained. The second face 200d of the fibrous texture 200 is intended to form the fibrous reinforcement of the extrados face of the blade to be obtained. The fibrous texture 200 extends in an additional direction Ds perpendicular to the horizontal direction DH and to the vertical direction Dv between a first edge 200e and a second edge 200f. The additional direction Ds will correspond after shaping the fiber texture 200 to the chord direction of the blade to be obtained. The first edge 200e of the fiber texture 200 is intended to form the leading edge of the blade to be obtained. The second edge 200f of the fiber texture 200 is intended to form the trailing edge of the blade to be obtained.

[0046] According to the invention, the weaving of the fibrous texture is carried out using structural threads made of a first material and damping threads made of a second material, the first material and the second material being different. The first material corresponds to a structural material. The first material is preferably a material conventionally used for weaving a blade fibrous texture. The second material corresponds to a damping material. The second material makes it possible to confer intrinsic mechanical damping properties to the blade.

[0047] The first material is preferably carbon. However, it does not depart from the scope of the invention if the first material is ceramic or glass. The first material may, for example, be a material from silicon carbide, alumina, mullite, silica, an aluminosilicate or a borosilicate.

[0048] The second material is a linear polyamide, a polyester, a polyethylene or a polyazole. If the second material is a linear polyamide, the second material is preferably nylon. If the second material is a polyester, the second material is preferably Vectran®. If the second material is a polyazole, the second material is preferably Zylon®. Thus, the second material may be one of nylon, Vectran®, polyethylene or Zylon®.

[0049] High modulus Zylon® is a particularly interesting material in the context of the invention. Indeed, Zylon® allows damping while maintaining significant stiffness. The blade comprising Zylon® fibers thus has intrinsic damping properties without losing stiffness. The use of Zylon® as a second material is particularly interesting when the first material is carbon. Indeed, the elastic modulus of high modulus Zylon® is approximately 270 GPa, which is a value very close to the elastic modulus of standard IM7 type carbon fibers which is approximately 276 GPa. Thus, the introduction of Zylon® damping yarns instead of structural carbon yarns during weaving is not to the detriment of the stiffness of the blade.

[0050] Preferably, the structural yarns made of the first material have an average diameter similar to the average diameter of the damping yarns made of the second material. Thus, the structural yarns made of the first material and the damping yarns made of the second material have the same count, which simplifies the production of the weaving and the use of damping yarns made of the second material within the weaving. It is of course not outside the scope of the invention if the structural yarns made of the first material and the yarns Second material damping yarns have different counts. For example, second material damping yarns can have a count between 1.5 and 2.5 times the count of first material structural yarns.

[0051] The introduction of damping threads made of a second material during the weaving of the fibrous texture 200 must be carried out so that said damping threads work in traction in the final blade for the vibrations that it is desired to damp.

[0052] In the example illustrated in the figures, the damping threads made of second material are present in the root portion 201 of the fiber texture 200. The aerodynamic profile portion 203 is devoid of damping threads made of second material. However, preferably, the damping threads made of second material are present in the aerodynamic profile portion 203. In this case, preferably, the root portion 201 of the fiber texture 200 is devoid of damping threads made of second material. Indeed, the aerodynamic profile of the blade to be produced is more subject to mechanical stresses requiring damping than the root of the blade to be produced.

[0053] The aerodynamic profile portion 203 of the fibrous texture 200 comprises, along the vertical direction Dv, a first surface portion, a core portion, and a second surface portion. The first surface portion, the core portion, and the second surface portion are superimposed along the vertical direction Dv. The core portion is arranged between the first and second surface portions along the vertical direction Dv. The first surface portion comprises a portion of the first face 200c of the fibrous texture 200, and the second surface portion comprises a portion of the second face 200d of the fibrous texture 200. The thickness of the core portion along the vertical direction Dv may represent at least 40% of the thickness of the aerodynamic profile portion 203 along the vertical direction Dv.In particular, the thickness of the core portion along the vertical direction Dv may represent at least 50% of the thickness of the aerodynamic profile part 203 along the vertical direction Dv. The core portion may not extend to the first edge 200e and to the second edge 200f. Thus, the core portion extends along the supplementary direction Ds over a distance less than the width of the aerodynamic profile part 203 along the supplementary direction Ds. The core portion may be arranged between a first lateral portion and a second lateral portion of the aerodynamic profile part 203 along the supplementary direction Ds-.

[0054] According to a preferred embodiment, the damping threads made of second material are present in the first and second surface portions of the aerodynamic profile part 203 of the fibrous texture 200. Preferably, in this preferred embodiment, the core portion of the aerodynamic profile part 203 of the fibrous texture 200 is devoid of damping threads made of a second material. Indeed, it is preferable for the damping threads made of a second material to be located close to the surfaces of the aerodynamic profile portion 203 of the fibrous texture 200, since these are the areas most subject to mechanical stresses requiring damping.

[0055] Preferably, the volume proportion of damping yarns in second material in the fibrous texture 200 is between 40% and 60% of the total volume of yarns. Such a proposal in damping yarns can be achieved even when the foot portion 201 of the fibrous texture 200 is devoid of damping yarns and / or even when the core portion of the aerodynamic profile portion 203 of the fibrous texture 200 is devoid of damping yarns.

[0056] The damping threads made of second material may be woven as warp threads. In this configuration, several eyelets 121a of the harness 120 of the loom 100 are traversed by damping threads made of second material to allow them to be woven in the warp direction. All the warp threads of the fibrous texture may be made of second material. However, preferably, only a portion of the warp threads of the fibrous texture is made of second material. The damping threads made of second material are preferably woven into portions of the fibrous texture intended to form portions of the blade particularly subject to vibrations. Thus, the damping warp threads made of second material are preferably present in the first and second surface portions of the aerodynamic profile portion 203 of the fibrous texture 200.The damping warp yarns of second material are optionally present in the first lateral portion and the second lateral portion of the airfoil portion 203. Preferably, the warp yarns of the core portion of the airfoil portion 203 are only structural yarns of first material.

[0057] The use of damping warp yarns is particularly advantageous for improving the resistance of the blade to the first mode and the second mode of bending of the blade. In particular, to improve the resistance of the blade to the first mode of bending, the damping warp yarns are preferably present in the lower portion of the airfoil portion 203 extending in the horizontal direction Dh from the transition portion 202 or the root portion 201. Thus, damping warp yarns are present in the lower third of the airfoil 203 extending from the transition portion 202 or the root portion 201.Preferably, to improve the blade resistance to the first bending mode, the damping warp yarns are present in the lower third of the airfoil 203 extending from the transition portion 202 or the root portion 201 in the first and second surface portions of the airfoil portion. 203. To improve the resistance to the second bending mode, the damping warp yarns are preferably present in the intermediate portion of the airfoil portion 203 extending in the horizontal direction DH between the upper portion and the lower portion of the airfoil portion 203. Thus, damping warp yarns are present in the intermediate third of the airfoil 203. Preferably, to improve the resistance of the blade to the second bending mode, the damping warp yarns are present in the intermediate third of the airfoil 203 in the first and second surface portions of the airfoil portion 203.

[0058] In the case where the damping yarns of second material are woven into warp yarns, the weft yarns may be structural yarns of first material. In the case where the damping yarns of second material are woven into warp yarns, a portion of the weft yarns may also be damping yarns of second material, the other portion of the weft yarns being structural yarns of first material.

[0059] The damping threads made of second material may be woven as weft threads. In this configuration, the gripper 132 of the rod 131 of the rapier 130 of the loom 100 grips one by one the damping threads made of second material stored on a reel of threads made of second material to allow them to be woven in the weft direction. All the weft threads of the fibrous texture may be made of second material. However, preferably, only a portion of the weft threads of the fibrous texture is made of second material. The damping threads made of second material are preferably woven into portions of the fibrous texture intended to form portions of the blade particularly subject to vibrations. Thus, the damping weft threads made of second material are preferably present in the first and second surface portions of the aerodynamic profile part 203 of the fibrous texture 200.Preferably, the weft yarns of the core portion of the airfoil portion 203 are only structural yarns of first material.

[0060] The use of damping weft threads is particularly advantageous for damping the first torsion mode of the blade to be produced. In particular, to improve the resistance of the blade to the first torsion mode, the damping weft threads are preferably present in the upper portion of the airfoil portion 203 extending in the horizontal direction DH from the upper edge 200b. Thus, damping weft threads are present in the upper third of the airfoil 203 comprising the upper edge 200b. Preferably, to improve the resistance of the blade to the first torsion mode, the damping weft threads are present in the upper third of the airfoil 203 comprising the upper edge 200b in the first and second surface portions of the aerodynamic profile part 203.

[0061] The damping weft yarns may be present in the root portion 201 of the fiber texture 200, as illustrated in the example of [Fig. 3], even if this is not a preferred embodiment. In [Fig. 3], a portion of the weft yarns 220 of the root portion 201 of the fiber texture 200 are structural weft yarns 221 made of the first material and the other portion of the weft yarns 220 of the root portion 201 of the fiber texture 200 are damping weft yarns 222 made of the second material. In the example illustrated in [Fig. 3], the weft yarns 220 of the aerodynamic profile portion 203 and the transition portion 202 of the fiber texture 200 are made of the first material. In the case where the damping yarns in the second material are woven in the weft direction, the warp yarns may be structural yarns in the first material. Thus, in the example illustrated in [Fig.3], the warp threads 210 are all structural warp threads 211 of first material. In the case where the damping threads of second material are woven in the weft direction, a part of the warp threads may also be damping threads of second material, the other part of the warp threads being structural threads of first material.

[0062] The fibrous texture thus obtained is then shaped so as to obtain a fibrous preform 20. An example of a fibrous preform 20 is illustrated in [Fig.4]. The fibrous preform 20 is then densified by a matrix. The densification of the fibrous preform 20 consists of filling the porosity of the preform 20, in all or part of its volume, with the material constituting the matrix.

[0063] Densification can be carried out in a manner known per se using the liquid process (LC). The liquid process consists of 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 mold that can be sealed with a housing having the shape of the final molded blade. Then, the mold is closed and the liquid matrix precursor (for example a resin) is injected into the entire housing to impregnate the entire fibrous part of the preform.

[0064] 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.

[0065] 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, can be polycarbosilane (PCS) or polytitanocarbosilane (PTCS) or polysilazane (PSZ) type resins, while liquid carbon precursors can be relatively high coke resins, such as phenolic resins. Several consecutive cycles, from impregnation to heat treatment, can be carried out to achieve the desired degree of densification.

[0066] According to one aspect of the invention, 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.

[0067] As illustrated in Figures 4 and 5, the injection of a liquid matrix precursor composition into the fiber preform 20 as well as its transformation into a matrix are here carried out in an injection tool 60 which comprises a first shell 61 comprising in its center a first imprint 61a corresponding in part to the shape and dimensions of the blade to be produced and a second shell 62 comprising in its center a second imprint 62a corresponding in part to the shape and dimensions of the blade to be produced.

[0068] Once the tool 60 is closed as illustrated in [Fig. 5], the first and second impressions 61a and 62a respectively of the first and second shells 61 and 62 together define an internal volume having the shape of the blade to be produced and in which the fiber preform 20 is placed. A compaction of the fiber preform can be carried out with the closing of the tool 60 in order to obtain a determined fiber rate in the preform. In this case, a compaction pressure is applied to the shells 61 and 62 for example by means of a press. The compaction of the fiber preform can also be carried out in a separate tool before introduction into the injection tool.

[0069] The tool 60 further comprises means for carrying out the injection of a liquid matrix precursor and the transformation of this precursor into a matrix. More specifically, in the example described here, the first shell 61 of the tool 60 comprises an injection port 61e intended to allow the injection of a liquid matrix precursor composition into the fiber preform while the second shell comprises an evacuation port 62s intended to cooperate with a pumping system for placing the tool under vacuum and drawing air during injection. The injection tool 60 also comprises a lower part 63 and a lower part upper part 64 between which the first and second shells 61 and 62 are placed, the lower part 63 and the upper part 64 being equipped with heating means (not shown).

[0070] Once the tool 60 is closed, the blade is molded by impregnating the preform 20 with a thermosetting resin that is polymerized by heat treatment. For this purpose, the well-known injection or transfer molding process known as RTM ("Resin Transfer Molding") is used. According to the RTM process, a resin, for example a thermosetting resin, is injected via the injection port 61e of the first shell 61 into the internal volume occupied by the preform 20. The port 62s of the second shell 62 is connected to a discharge conduit maintained under pressure (not shown). This configuration allows the establishment of a pressure gradient between the lower part of the preform 20 where the resin is injected and the upper part of the preform 20 located near the port 62s.In this way, the resin injected substantially at the level of the lower part of the preform 20 will gradually impregnate the entire preform by circulating in it up to the evacuation port 62s through which the surplus is evacuated. Of course, the first and second shells 61 and 62 of the tooling 60 may respectively comprise several injection ports and several evacuation ports.

[0071] The resin used may be, for example, an epoxy resin with a temperature class of 180°C (maximum temperature supported without loss of characteristics). 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.

[0072] After injection and polymerization, the blade is demolded. A trimming or machining step can be carried out on the part produced to obtain the blade.

[0073] The blade thus obtained can be a moving blade or a fixed blade, for example a rectifier blade.

Claims

Claims

1. Fibrous texture (200) intended to form the fibrous reinforcement of a turbomachine blade made of composite material, the fibrous texture (200) being obtained by three-dimensional weaving between a plurality of warp threads (210) extending in a longitudinal direction and a plurality of weft threads (220) extending in a transverse direction, a portion of the threads (221) being made of a first material, the fibrous texture (200) being characterized in that another portion of the threads (222) is made of a second damping material different from the first material, the second material being a linear polyamide, a polyester, a polyethylene or a polyazole.

2. The fibrous texture (200) of claim 1, wherein the second material is poly(p-phenylene-2,6-benzobisoxazole).

3. The fibrous texture (200) of claim 1 or 2, wherein the first material is carbon.

4. A fibrous texture (200) according to any one of claims 1 to 3, wherein the yarns made from the second material are warp yarns.

5. A fibrous texture according to any one of claims 1 to 3, wherein the yarns (222) made from the second material are weft yarns (220).

6. Fibrous preform (20) obtained by shaping the fibrous texture (200) according to any one of claims 1 to 5.

7. Fibrous preform according to claim 6, said preform (20) being intended to form the fibrous reinforcement of a fan blade.

8. Turbomachine blade made of composite material whose fiber reinforcement comprises the fiber preform (20) according to claim 6 or 7.

9. A blade according to claim 8, the blade being made of an organic matrix composite material.

10. A method of manufacturing a turbomachine blade made of an organic matrix composite material comprising: - producing a fibrous texture (200) according to any one of claims 1 to 5, - shaping the fibrous texture (20) so as to obtain a fibrous preform (20), - injecting a matrix precursor resin into the fibrous preform (20), - treatment of the resin in order to form the organic matrix in the porosities of the fibrous preform (20) so as to obtain the blade in composite material.

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