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 in composite material, and more particularly to the manufacture of blades in organic matrix composite material (OMC). Previous technique

[0002] The fabrication 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. This improves the efficiency of the turbomachine, resulting in reduced fuel consumption.

[0003] The fibrous reinforcement of turbomachine blades is formed by a fibrous preform. The fibrous 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 fibrous preform and treated so as to form an organic matrix within the pores of the fibrous 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 failure. 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 provides mechanical damping without modifying the blade design.

[0005] However, elastomer pads are difficult to dimension to obtain sufficient mechanical damping. Furthermore, elastomer pads wear out gradually, requiring regular maintenance to replace them. Description of the invention

[0006] The present invention aims to provide a blade made of composite material incorporating 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 yarns extending along a longitudinal direction and a plurality of weft yarns extending along a transverse direction, a portion of the yarns being made of a first material, the fibrous texture being characterized in that another part of the yarns 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 incorporating fibers that perform a damping function during the weaving of the fibrous preform, the final blade possesses intrinsic damping characteristics. It is therefore no longer necessary to use additional parts, such as elastomer pads, to dampen the vibrations to which the blade is subjected. Since the damping fibers are located inside the blade, they are not directly exposed to the external environment. Consequently, the damping function of the blade degrades very little over time. Finally, the use of such damping fibers also improves the blade's resistance to impacts and shocks, and enhances its durability 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 by the trade name Zylon®. Zylon® is particularly advantageous because it can exhibit an elastic modulus similar to that of carbon. Thus, the introduction of Zylon® fibers during weaving will not result in a decrease in the blade stiffness. Furthermore, the introduction of Zylon® fibers during weaving does not add any constraints to the subsequent blade manufacturing process. Indeed, Zylon® fibers withstand densification processes of the fibrous preform very well, for example, resin injection, and also react well during machining operations or 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 yarns extending along a longitudinal direction and a plurality of weft yarns extending along a transverse direction, a part of the yarns being made of a first material, the fibrous preform being characterized in that another part of the yarns 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 yarns made of the second material are weft yarns.

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

[0015] According to another particular embodiment of the invention, the fibrous texture comprises, along the longitudinal direction, at least one foot portion intended to form the fibrous reinforcement of the foot 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 yarns made of the second damping material being present in the first and second surface portions.

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

[0017] Thus, the damping yarns in the 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 portion of the core along the vertical direction represents at least 40% of the thickness of the aerodynamic profile portion along the vertical direction.

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

[0020] Thus, the invention proposes a fibrous preform 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 yarns extending along a longitudinal direction and a plurality of weft yarns extending along a transverse direction, a part of the yarns being made of a first material, the fibrous preform being characterized in that another part of the yarns 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 being intended to form the fibrous reinforcement of a blower blade.

[0022] The invention further relates to a turbomachine blade made of composite material whose fibrous reinforcement comprises the fibrous preform as described above.

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

[0024] The invention ultimately proposes a method for manufacturing a turbomachine blade from an organic matrix composite material comprising:

[0025] - the creation of a fibrous texture as described above,

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

[0027] - the injection of a matrix precursor resin into the fibrous preform,

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

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

[0030] [Fig.2] The [Fig.2] is a schematic perspective view of the loom of the [Fig.1] with a crowd creation.

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

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

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

[0034] The invention applies generally to the manufacture of blades from a fibrous preform. The fibrous preform is obtained by shaping a fibrous texture produced by three-dimensional weaving. "Three-dimensional weaving" here refers to a weaving method in which at least some of the warp yarns bind weft yarns over several weft layers. A fibrous texture produced by three-dimensional weaving may include another type of weave on its surface, for example, two-dimensional weaving, in order to improve its surface finish.

[0035] The fibrous texture may, for example, have a three-dimensional weave structure of the interlock or multisatin type. Various 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 loom 100 for producing the fibrous texture 200 used to form the fibrous preform. The loom 100 produces the fibrous texture 200 by weaving a plurality of warp yarns 210 with a plurality of weft yarns 220. The fibrous texture 200 extends lengthwise along a horizontal direction DH and in thickness along a vertical direction Dv on the 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 includes a harness 120 comprising control or heddle wires 121, each control wire 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 The control wire 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 attached to the frame 113 of the loom 100. The control wires 121 extend in the vertical direction Dv. The harness 120 may also include a heddle board 122.

[0038] Each control wire 121 includes an eyelet 121a through which a warp wire 210 passes. Each warp wire 210 of the loom 100 passes through an eyelet 121a of the harness 120. The warp wires 210 are arranged 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 wires 220 according to the weaving pattern(s) programmed in the loom 100. The weft wires 220 are inserted between the warp wires 210 by column extending along the vertical direction Dv. In order to allow the introduction of each column of weft yarns 220 during the weaving of texture 200, a warp yarn calling system 210 (not shown in figures 1 and 2) is associated with the loom 100.This system, placed downstream of the loom 100, has the role of holding all the warp threads 210 together in a bridling device and of allowing the advancement of the warp threads 210 a determined distance along 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 direction of weaving, along the horizontal direction DH.

[0040] The control wires 121 and their associated eyelet 121a are able to move along the vertical direction Dv. In [Fig. 1], all the control wires 121 are in a neutral position in which no tension is exerted by the Jacquard mechanism 110. In this configuration, no swarm is created and all the warp wires 210 extend parallel to the horizontal direction DH.

[0041] During the creation of a swarm, as illustrated in [Fig.2], part of the control wires 121 are subjected to tensile forces exerted by the control hooks 111. In this configuration, the control wires allow warp wires to be raised or lowered, so as to separate an upper layer of warp wires from a lower layer of warp wires by an opening, called a swarm.

[0042] The loom 100 also includes a spear 130, located downstream of the control wires 121. The spear 130 consists of a rod 131, one end of which is connected to an actuation system (not shown in Figures 1 and 2) that drives the rod 131 back and forth. The other end of the rod 131 is fitted with a gripper 132 which, after passing through the swarm during the journey As the rod 131 moves forward, it can pick up a weft yarn 220 stored on a reel 140 and unwind it into the sheaf during the rod 131's return journey. The weft yarn 220, thus placed within the sheaf, is then cut near the reel 140 by a cutting tool 150 and released at its other end by the gripper 132. A reed 160, located upstream of the rod 130 and downstream of the harness 120 in its resting position, is then folded down to compact the weft yarn(s) 220 introduced into the sheaf. The rod 130 is then ready to pick up a new weft yarn 220 from the reel 140 and place it either in the same sheaf or in a different one, depending on the defined weave pattern. The fibrous texture 200, exhibiting a three-dimensional weave between the warp yarns 210 and the weft yarns 220, is thus progressively formed.

[0043] Preferably, the loom 100 further comprises a guiding device 170 for the fibrous texture 200 located downstream of the control wires 121 and the spear 130. Such a guiding device 170 is notably described in document FR 3 074 195 AL. In the example described here, the guiding device 170 comprises a lower jaw 171 and an upper jaw 172, each connected to an actuation means (not shown in Figures 1 and 2) which is capable, on the one hand, of maintaining the fibrous texture 200 and, on the other hand, of moving the jaws 171 and 172 along the vertical direction Dv. It is thus easier to create swarms in the lower or upper layers of warp wires 210, even with a large number of superimposed layers of warp wires 210 in the vertical direction Dv.

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

[0045] The fibrous texture 200 extends along the horizontal direction DH between a lower edge 200a and an upper edge 200b. After shaping the fibrous texture 200, the horizontal direction DH will correspond to the span direction of the blade to be obtained. The fibrous texture 200 extends along 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 lower surface of the blade to be obtained. The second face 200d of the fibrous texture 200 is intended to form the fibrous reinforcement of the upper surface of the blade to be obtained. The fibrous texture 200 extends following an additional direction Ds perpendicular to the horizontal direction DH and the vertical direction Dv between a first edge 200e and a second edge 200f. The additional direction Ds will correspond, after shaping the 200 fiber texture, to the chord direction of the blade to be obtained. The first edge 200e of the 200 fiber texture is intended to form the leading edge of the blade to be obtained. The second edge 200f of the 200 fiber texture 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 yarns made of a first material and damping yarns made of a second material, the first and second materials being different. The first material is a structural material. Preferably, this first material is a material conventionally used for weaving a fibrous blade texture. The second material is a damping material. This second material provides the blade with intrinsic mechanical damping properties.

[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 such as 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, it is preferably nylon. If the second material is a polyester, it is preferably Vectran®. If the second material is a polyazole, it is preferably Zylon®. Thus, the second material can 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® provides damping while maintaining significant stiffness. The blade incorporating Zylon® fibers thus exhibits intrinsic damping properties without any loss of stiffness. The use of Zylon® as a secondary material is particularly advantageous when the primary material is carbon. In fact, the elastic modulus of high-modulus Zylon® is approximately 270 GPa, which is very close to the elastic modulus of standard IM7 carbon fibers, which is approximately 276 GPa. Thus, the introduction of Zylon® damping yarns in place of structural carbon yarns during weaving does not compromise the blade's stiffness.

[0050] Preferably, the structural wires in the first material have a similar average diameter to the average diameter of the damping wires in the second material. Thus, the structural wires in the first material and the damping wires in the second The materials have the same fiber count, which simplifies the weaving process and the use of damping yarns as a second material within the weave. Of course, this does not depart from the scope of the invention if the structural yarns as the first material and the damping yarns as the second material have different fiber counts. For example, the damping yarns as the second material may have a fiber count between 1.5 and 2.5 times that of the structural yarns as the first material.

[0051] The introduction of damping yarns in second material during the weaving of the fibrous texture 200 must be carried out so that said damping yarns work in tension in the final blade for the vibrations which it is desired to dampen.

[0052] In the example illustrated in the figures, the damping fibers made of the second material are present in the root portion 201 of the fibrous texture 200. The airfoil portion 203 is devoid of damping fibers made of the second material. However, preferably, the damping fibers made of the second material are present in the airfoil portion 203. In this case, preferably, the root portion 201 of the fibrous texture 200 is devoid of damping fibers made of the second material. Indeed, the airfoil of the blade to be produced is subjected to greater mechanical stresses requiring damping than the root of the blade to be produced.

[0053] The airfoil 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 located 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 airfoil 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 airfoil section 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 additional direction Ds over a distance less than the width of the airfoil section 203 along the additional direction Ds. The core portion may be located between a first lateral portion and a second lateral portion of the airfoil section 203 along the additional direction Ds.

[0054] According to a preferred embodiment, the second-material damping strands are present in the first and second surface portions of the airfoil portion 203 of the fibrous texture 200. Preferably, in this preferred embodiment, the core portion of the airfoil portion 203 of the fibrous texture 200 is devoid of second-material damping strands. Indeed, it is preferable for the second-material damping strands to be located close to the surfaces of the airfoil portion 203 of the fibrous texture 200, as these are the areas most subjected to mechanical stresses requiring damping.

[0055] Preferably, the volume proportion of damping yarns in the second material of the fibrous texture 200 is between 40% and 60% of the total yarn volume. Such a proportion of 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 airfoil portion 203 of the fibrous texture 200 is devoid of damping yarns.

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

[0057] The use of damping chain wires is particularly advantageous for improving the blade's resistance to the first and second modes of blade bending. In particular, to improve the blade's resistance to the first mode of bending, the damping chain wires are preferably located in the lower portion of the airfoil section 203 extending in the horizontal direction DH from the transition section 202 or the root section 201. Thus, damping chain wires are located in the lower third of the airfoil section 203 extending from the transition section 202 or the root section 201. foot 201. Preferably, to improve the blade's resistance to the first bending mode, damping chain wires are present in the lower third of the airfoil 203 extending from the transition portion 202 or the foot portion 201 into the first and second surface portions of the airfoil 203. To improve resistance to the second bending mode, damping chain wires are preferably present in the middle portion of the airfoil 203 extending along the horizontal direction DH between the upper and lower portions of the airfoil 203. Thus, damping chain wires are present in the middle third of the airfoil 203.Preferably, to improve the resistance of the blade to the second mode of bending, the damping chain wires are present in the middle third of the aerodynamic profile 203 in the first and second surface portions of the aerodynamic profile part 203.

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

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

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

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

[0062] The fibrous texture thus obtained is then shaped 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 achieved in a manner known per se using the liquid-liquid process (CVL). The liquid-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, possibly diluted in a solvent. The preform is placed in a mold that can be sealed tightly with a cavity having the shape of the final molded blade. The mold is then closed, and the liquid matrix precursor (for example, a resin) is injected into the entire cavity to impregnate all the fibrous material 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 removal of any solvent and crosslinking of the polymer, the preform always being held in the mold having a shape corresponding to that of the part to be produced.

[0065] In the case of forming 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, particularly SiC, can be polycarbosilane (PCS), polytitanocarbosilane (PTCS), or polysilazane (PSZ) type resins, while liquid carbon precursors can be resins with a relatively high coke content, 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, particularly in the case of forming an organic matrix, the densification of the fibrous preform can be achieved by the well-known resin transfer molding (RTM) process. 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 containing the fibrous preform. A pressure gradient is generally established in this internal space between the point where the resin is injected and the resin discharge ports 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 fibrous preform 20 and its transformation into a matrix are carried out here in an injection tool 60 which includes a first shell 61 comprising in its center a first impression 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 impression 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 cavities 61a and 62a of the first and second shells 61 and 62, respectively, together define an internal volume having the shape of the blade to be produced, and in which the fiber preform 20 is placed. The fiber preform can be compacted while the tool 60 is closed to obtain a specific fiber content. In this case, compaction pressure is applied to the shells 61 and 62, for example, using a press. The fiber preform can also be compacted in a separate tool before being introduced into the injection mold.

[0069] The tooling 60 further includes means for injecting a liquid matrix precursor and transforming this precursor into a matrix. More specifically, in the example described here, the first shell 61 of the tooling 60 includes an injection port 61e for injecting a composition The matrix precursor liquid is contained within the fibrous preform, while the second shell includes a vent port 62s for use with a pumping system to evacuate the tooling and draw air during injection. The injection tooling 60 also includes a lower portion 63 and an upper portion 64 between which the first and second shells 61 and 62 are positioned, the lower portion 63 and the upper portion 64 being equipped with heating means (not shown).

[0070] Once the tooling 60 is closed, the blade is molded by impregnating the preform 20 with a thermosetting resin, which is then polymerized by heat treatment. The well-known injection or transfer molding process known as RTM ("Resin Transfer Molding") is used for this purpose. 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 pressurized discharge conduit (not shown). This configuration establishes 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 at approximately the lower part of the preform 20 will progressively impregnate the entire preform as it circulates within it until it reaches the discharge port 62s, through which the excess is evacuated. Of course, the first and second shells 61 and 62 of the tooling 60 can respectively include several injection ports and several discharge ports.

[0071] The resin used can be, for example, an epoxy resin with a temperature class of 180 °C (maximum temperature that can withstand it without loss of properties). 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 performed 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

Demands

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 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) is made of a second damping material different from the first material, the second material being poly(p-phenylene-2,6-benzobisoxazole).

2. Fibrous texture (200) according to claim 1, wherein the first material is carbon.

3. Fibrous texture (200) according to any one of claims 1 to 2, wherein the yarns made of the second material are warp yarns.

4. Fibrous texture according to any one of claims 1 to 2, wherein the yarns (222) made of the second material are weft yarns (220).

5. Fibrous preform (20) obtained by shaping the fibrous texture (200) according to any one of claims 1 to 4.

6. Fibrous preform according to claim 5, said preform (20) being intended to form the fibrous reinforcement of a blower blade.

7. Turbomachine blade made of composite material having the fibrous reinforcement comprising the fibrous preform (20) according to claim 5 or 6.

8. Blade according to claim 7, the blade being made of organic matrix composite material.

9. A method for manufacturing a turbomachine blade from an organic matrix composite material comprising: - producing a fibrous texture (200) according to any one of claims 1 to 4, - shaping the fibrous texture (20) so as to obtain a fibrous preform (20), - injecting a matrix precursor resin into the fibrous preform (20), - the 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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