TURBINE MOTOR BLADE MADE OF COMPOSITE MATERIAL WITH FIBER TEXTURE

Description

Technical Field

[0001] The invention relates to the general field of composite material parts for aeronautics. More specifically, the invention relates to a turbomachine blade made of composite material comprising a fibrous texture intended to form the fibrous reinforcement. Prior art

[0002] In the field of aeronautical turbomachinery, reducing the mass of parts is a major issue both in terms of manufacturing costs of these parts, and in terms of the energy and environmental efficiency of turbomachinery. This issue has rapidly led to the development of parts made of composite materials, particularly organic matrix composites (OMC), to replace traditional metal parts in different parts of the turbojet engine. An example is described in application FR 3040909.

[0003] However, the production of blades from organic matrix composite material poses certain problems, particularly in terms of impact resistance. Indeed, the location of these blades, for example in the fan or compressor, can expose them to impacts from objects of various types (birds, gravel, blocks of ice, sand, etc.) and the CMO blades can then become damaged or eroded.

[0004] We know the positioning of a metal foil on the leading edge of the blades to protect it from impacts while maintaining a reduced mass. However, the body of the blades made of composite material of the fan can have areas of low thickness to respond to aerodynamic constraints which are still likely to be damaged in the event of an impact.

[0005] There is therefore a need for a reduced mass turbomachine blade that is more impact resistant. Statement of the invention

[0006] To this end, the invention proposes a turbomachine blade made of composite material comprising a fibrous reinforcement densified by a matrix and formed by a fibrous texture, the texture being in a single piece and having a three-dimensional weave between a plurality of warp yarns or strands of first fibers extending in a longitudinal direction and a plurality of weft yarns or strands of first fibers extending in a transverse direction, the texture comprising a blade root portion and a blade blade portion extending between the blade root portion and a free end of the fibrous texture,the texture extending in the transverse direction between a first edge corresponding to a leading edge of the blade and a second edge corresponding to a trailing edge of the blade. The fibrous texture is characterized in that the blade portion has a reinforced zone extending in the longitudinal direction from the free end of the fibrous texture over a first length less than or equal to 20%, preferably less than or equal to 10%, of the length of the fibrous texture measured in the longitudinal direction, and in the transverse direction from the second edge over a second length less than or equal to 75% of the width of the fibrous texture measured in the transverse direction at the free end of the texture, the reinforced zone comprising weft yarns or strands made of second fibers different from the first fibers, the second fibers having an elongation at break greater than that of the first fibers,and in that a first volume rate of second fibers in the reinforced zone is greater than a second volume rate of second fibers in the rest of the part corresponding to the fiber reinforcement of the blade of the vane.,

[0007] In other words, there are more second fibers in the reinforced zone than in the rest of the blade portion. In particular, the second fibers may be present predominantly in the weft yarns of the reinforced zone.

[0008] The term “volume ratio of second fibers in a part of a texture” means the ratio between the volume occupied by said fibers and the total volume occupied by all the fibers in this part. The threads or strands may consist solely of fibers of the same material. “Three-dimensional weaving” or “3D weaving” means a weaving method by which at least some of the warp threads bind weft threads over several weft layers. A reversal of roles between warp and weft is possible in the present text and must be considered as also covered by the claims.

[0009] With such a fibrous texture, it is possible to produce a blade capable of better resisting impacts from objects, in particular small or medium-sized birds, for which localized damage is observed at the trailing edge at the blade tip and in the transverse direction. The greater elongation at break of the second fibers located in the reinforced zone allows the blade, which will include such a texture as reinforcement, to withstand these impacts without significantly increasing its mass (the mass of the second fibers is generally greater than that of the first fibers). The use of the second fibers for weft yarns or strands makes the manufacture of such a fibrous texture easy since it is sufficient to replace the weft yarns or strands in first fibers with those in second fibers during weaving in a loom, as will be detailed later.

[0010] In an exemplary embodiment, the blade portion may further comprise a transition zone adjacent in the transverse direction to the reinforced zone and in which the weft yarns or strands in second fibers are replaced by weft yarns or strands in first fibers, the weft yarns or strands in second fibers progressively exiting the fibrous texture in the transition zone at positions offset in the transverse direction, said weft yarns or strands in second fibers being progressively replaced by weft yarns or strands in first fibers at the offset exit positions of the weft yarns or strands in second fibers.

[0011] This arrangement allows the damage to the blade which includes this texture as reinforcement to be distributed progressively in the transverse direction and not to be concentrated on the same longitudinal plane (warp plane), which further improves the blade's resistance in the event of impacts.

[0012] In an exemplary embodiment, the transition zone may extend transversely over a length of between 10 mm and 100 mm.

[0013] In an exemplary embodiment, the volume ratio of second fibers in the reinforced zone may decrease away from the free end of the fiber texture in the longitudinal direction. This arrangement allows a progressive transition of stiffness in the longitudinal direction which further improves impact resistance.

[0014] In an exemplary embodiment, the first length may be less than or equal to 100 mm.

[0015] In an exemplary embodiment, the second length may be less than or equal to 50% of the width of the fibrous texture measured in the transverse direction at the free end of the texture.

[0016] In an exemplary embodiment, the first fibers may be made of carbon, and the second fibers may be made of a material chosen from the following: glass, basalt, aramid or polyester.

[0017] In an exemplary embodiment, the first volume rate may be at least 30%, preferably between 30% and 90%.

[0018] The invention also relates to a fan blade made of composite material comprising a fibrous reinforcement densified by a matrix, the fibrous reinforcement of the blade comprising a fibrous texture such as that described above.

[0019] The invention also relates to an aeronautical turbomachine comprising a fan comprising a rotating disk and a plurality of blades such as that presented above mounted on the rotating disk.

[0020] Finally, the invention relates to a method for manufacturing a turbomachine blade made of composite material comprising a fibrous reinforcement densified by a matrix and formed by a fibrous texture intended to form the fibrous reinforcement, the texture being in a single piece and being obtained by three-dimensional weaving between a plurality of warp yarns or strands of first fibers extending in a longitudinal direction and a plurality of weft yarns or strands of first fibers extending in a transverse direction, the texture comprising a blade root portion and a blade blade portion extending between the blade root portion and a free end of the fibrous texture, the texture extending in the transverse direction between a first edge corresponding to a leading edge of the blade and a second edge corresponding to a trailing edge of the blade.The method is characterized in that the blade portion has a reinforced zone extending in the longitudinal direction from the free end of the fibrous texture over a first length less than or equal to 20%, preferably less than or equal to 10%, of the length of the fibrous texture measured in the longitudinal direction, and in the transverse direction from the second edge over a second length less than or equal to 75% of the width of the fibrous texture measured in the transverse direction at the free end of the texture, the reinforced zone comprising weft yarns or strands made of second fibers different from the first fibers, the second fibers having an elongation at break greater than that of the first fibers, and in that a first volume ratio of second fibers in the reinforced zone is greater than a second volume ratio of second fibers in the remainder of the blade portion.

[0021] In an exemplary embodiment, the blade portion may further comprise a transition zone adjacent in the transverse direction to the reinforced zone in which the weft yarns or strands in second fibers are replaced by weft yarns or strands in first fibers, the method comprising the progressive exit of the weft yarns or strands in second fibers in the transition zone at positions offset in the transverse direction and the insertion of weft yarns or strands in first fibers in replacement of the weft yarns or strands in second fibers at the offset exit positions of the weft yarns or strands in second fibers.

[0022] A method for manufacturing a fan blade made of a composite material comprising a fibrous reinforcement densified by a matrix may comprise the following steps: a fibrous texture such as that presented above is produced, said texture is shaped to obtain a blade preform, and a matrix is ​​formed in the porosity of the preform to obtain the blade. The fibrous texture is obtained by three-dimensional weaving, and may for example have an interlock-type weave. The matrix may be an organic matrix and obtained from a resin. The matrix may thus be formed by resin injection molding (RTM process or “Resin Transfer Molding”). Brief description of the drawings

[0023] [ Fig. 1 ] There figure 1 is a schematic longitudinal sectional view of an aeronautical turbomachine. Fig. 2 ] There figure 2 shows an aeronautical turbomachine fan blade according to one embodiment of the invention. Fig. 3 ] There figure 3 shows a fibrous texture according to one embodiment of the invention. Fig. 4 ] There figure 4 shows an enlarged schematic view of the fibrous texture of the figure 3 at the free end of the latter, where we see the path of certain weft threads. Fig. 5 ] There Figure 5 shows a longitudinal sectional view in the reinforced area of ​​the fibrous texture at the free end thereof. Description of the embodiments

[0024] There figure 1 shows a schematic view in longitudinal section of an aeronautical turbomachine 1, here a double-flow turbojet centered on the axis AA. It comprises, from upstream to downstream in the direction F of flow of the gas flow in the turbomachine: a fan 2, a low-pressure compressor 3, a high-pressure compressor 4, a combustion chamber 5, a high-pressure turbine 6, and a low-pressure turbine 7.

[0025] The fan 2 comprises in particular a rotating disc 8 on which are mounted a plurality of fan blades 10, one of which is shown in the figure 2 .

[0026] The fan blade 10 extends in a longitudinal direction L between a root 11 and a free end 12, and in a transverse direction T between a leading edge 13 and a trailing edge 14. Between the root 11 and the end 12, the blade comprises a stilt 15 and a blade body 16 located between the stilt 15 and the end 12. The fan blade 10 is made of a composite material comprising a fiber reinforcement densified by a matrix.

[0027] In the illustrated example, the blade 10 has a metal leading edge 17, for example in the form of a metal foil. Such a metal leading edge 17 can be fixed after obtaining the blade 10, or be integrated into the blade 10 during its manufacturing process, in a known manner.

[0028] There figure 3shows a schematic view of a fibrous texture 100 intended to form the fibrous reinforcement of a turbomachine blade such as that of the figure 2 . This fibrous texture 100 can be obtained for example by three-dimensional weaving in a Jacquard type loom of a fibrous blank and cutting the excess threads from the woven fibrous blank.

[0029] The fibrous texture 100 may have a three-dimensional weave, and may comprise, for example, mainly an interlock or multi-layer weave. By “interlock weave”, it is meant a three-dimensional weave weave in which each layer of warp threads links several layers of weft threads with all the threads of the same warp column having the same movement in the plane of the weave. Document WO2006 / 136755 describes the production of such weave weaves. As will be described later, this fibrous texture may be shaped and then densified to obtain a fan blade 10 such as that illustrated in the figure 2 .

[0030] The fibrous texture 100 extends in the longitudinal direction L between a blade root portion 110 and a blade blade portion 120. The texture 100 has a free end 121 located at the end of the blade blade portion 120 opposite the blade root portion 110. A blade stilt portion 130 is present between the blade root portion 110 and the blade blade portion 120. Generally, the blade root portion 110 is thicker than the blade stilt portion 130, and the thickness of the blade blade portion 120 is variable. The fibrous texture 100 extends in the transverse direction T between a first edge 101 intended to form the leading edge 13 of the blade 10 and a second edge 102 intended to form the trailing edge 14 of the blade 10.

[0031] In the illustrated example, the longitudinal direction L also corresponds to the general direction in which the warp threads extend in the fiber texture 100, while the transverse direction T corresponds to the general direction in which the weft threads extend. It will be noted that, throughout the text, warp and weft may be interchanged.

[0032] The fibrous texture 100 has a three-dimensional or multi-layer weave between a plurality of warp yarns made of first fibers and a plurality of weft yarns made of first fibers. According to the invention, the fibrous texture 100 also has weft yarns made of second fibers, different from the first fibers, and which have an elongation at break greater than that of the first fibers. More specifically, the fibrous texture 100 has a reinforced zone 140 which comprises weft yarns made of second fibers.The reinforced zone 140 extends from the free end 121 of the fibrous texture in the longitudinal direction L over a first length L1 less than or equal to 20%, preferably less than or equal to 10%, of the length L0 of the fibrous texture 100 measured in the longitudinal direction L, and in the transverse direction T from the second edge 102 over a second length L2 less than or equal to 75% of the width L3 of the fibrous texture measured in the transverse direction T at the free end 121 of the fibrous texture 100. For example, the length L1 may be less than or equal to 100 mm. For example, the length L2 may be less than or equal to 50% of the width L3.

[0033] A first volume ratio of second fibers in the reinforced zone 140 is greater than a second volume ratio of second fibers in the rest of the blade portion 120. In other words, the second fibers are predominantly present in the reinforced zone 140 of the blade portion 120. The second fibers are predominantly located in the weft threads of said zone 140. The first volume ratio may be at least 30%, preferably between 30% and 90%.

[0034] The material of the first fibers can be carbon. The material of the second fibers can be chosen from the following: glass, basalt, aramid, polyester, or a combination of these materials. The following table gives common elongations at break of several fibers that can be used. [Table 1] fiber material - reference elongation at break (%) glass - AGY “S-2 Glass ®<” 5,2 glass - "E-Glass" 4,4 polyester 3,5 basalt 3 aramid - Dupont “Kevlar ®< 49” 2,4 carbon - Toray “HS T700” 2,1 carbon - Toray “HS TR30S” 1,9 carbon - Toray “HS T300” 1,5

[0035] For example, carbon may be chosen for the first fibers and glass for the second fibers. Several types of weft yarns or strands may also be used, which include different fibers having a higher elongation at break than the first fibers. Note that the material of the first and second fibers may be identical. For example, the first and second fibers may be carbon, provided that their elongations at break are different. For example, the first carbon fibers may be chosen from HexTow ®< IM7 (marketed by the Hexcel company), and the second carbon fibers from Torayca ®< T1100 (marketed by the Toray company).

[0036] The elongation at break of the first fibers may be, for example, less than or equal to 2.1%, and that of the second fibers greater than or equal to 2.4%.

[0037] The fibrous texture 100 further comprises a transition zone 150 which is adjacent to the reinforced zone 140 in the transverse direction T, in which the weft yarns in second fibers are replaced by weft yarns in first fibers. This transition zone 150 will be described in more detail using the figure 4 .

[0038] On the figure 4, the path of four weft threads T1, T2, T3 and T4 in second fibers which are woven in the reinforced zone 140 is schematically represented. The weft threads T1 to T4 are here inserted into the fiber texture 100 by the second edge 102 then woven with warp threads (not shown) in the reinforced zone 140, and finally exited the fiber texture 100 in the transition zone 150. In this example, the weft threads T1 to T4 in second fibers are progressively exited from the fiber texture 100 at positions offset along the transverse direction T. In other words, the weft threads T1 to T4 are exited from the fiber texture 100 at different transverse planes or warp planes P1, P2, P3 and P4.More specifically, in this example, the weft yarn T1 closest to the free end 121 of the fiber texture 100 is output at a warp plane P1 located closer to the first edge 101 than the warp plane P2 at which the weft yarn T2, which is further from the free end 121 than the weft yarn T1, is output. The same applies to the yarns T3 and T4 which are output at the warp planes P3 and P4 offset in the transverse direction T.

[0039] The weft yarns T1 to T4 are then replaced by weft yarns T5, T6, T7 and T8 as first fibers in the transition zone 150, at or in the immediate vicinity of the offset exit positions of the yarns T1, T2, T3 and T4 respectively. The weft yarns T5, T6, T7 and T8 are thus inserted into the fiber texture 100 in the transition zone 150 and then woven normally onto the remaining portion of the fiber texture 100. This arrangement makes it possible to distribute the positions where a change in stiffness occurs between the first fibers and the second fibers over several warp planes in order to further increase the impact resistance. For example, the transition zone 150 extends over a length L4 of between 10 mm and 100 mm.

[0040] There Figure 5shows a longitudinal sectional view of the fibrous texture 100 in the reinforced zone 140 illustrating the characteristic according to which the volumetric content of second fibers in the reinforced zone 140 decreases away from the free end 121 of the fibrous texture in the longitudinal direction L. Figure 5 shows only the weft threads in section. The weft threads in first fibers are shown in light and the weft threads in second fibers in black. It can be seen that the proportion of weft threads in second fibers in each column of weft threads decreases as one moves away from the free end 121. This arrangement ensures a progressive stiffness transition between the reinforced zone 140 and the rest of the blade portion 120 of the fiber texture 100 in the longitudinal direction L, in order to further increase the resistance in the event of an impact. The example shown in the Figure 5shows a longitudinal section of a reinforced zone having a thickness decrease corresponding to a reduction in the number of threads in the longitudinal direction. According to an alternative embodiment, the number of threads present in the reinforced zone is constant in the longitudinal direction.

[0041] To obtain a fan blade 10 such as that illustrated in the figure 2 , a fibrous texture 100 is produced by three-dimensional weaving, said texture is shaped to obtain a blade preform having the appropriate geometry, and a matrix is ​​formed in the porosity of the preform to obtain the blade. At the time of weaving, weft threads made of first fibers can be replaced by weft threads made of second fibers in the reinforced zone 140 of the fibrous texture as described above.

[0042] The fan blade 10 may be produced by a resin transfer molding (RTM) process where the preform is placed in a mold having the shape of the blade and into which a resin is injected and then polymerized. In this case, the matrix may be an organic matrix and obtained from an epoxy type resin.

Claims

1. A turbomachine (1) blade (10) made of composite material comprising a fibrous reinforcement densified by a matrix and formed by a fibrous texture (100), the texture being in one piece and having a three-dimensional weaving between a plurality of warp yarns or strands made of first fibers extending along a longitudinal direction (L) and a plurality of weft yarns or strands made of first fibers extending along a transverse direction (T), the texture comprising a portion corresponding to a fibrous reinforcement of a root (110) of the blade (10) and a portion corresponding to a fibrous reinforcement of a airfoil (120) of the blade (10) extending between the portion corresponding to the fibrous reinforcement of the root of the blade and a free end (121) of the fibrous texture, the texture extending along the transverse direction (T) between a first edge (101) corresponding to a leading edge (13) of the blade and a second edge (102) corresponding to a trailing edge (14) of the blade, characterized in that the portion corresponding to the fibrous reinforcement of the airfoil (120) of the blade has a reinforced area (140) extending along the longitudinal direction (L) from the free end (121) of the fibrous texture over a first length (L1) less than or equal to 20% of the length (L0) of the fibrous texture measured in the longitudinal direction, and along the transverse direction (T) from the second edge (102) over a second length (L2) less than or equal to 75% of the width (L3) of the fibrous texture measured in the transverse direction at the level of the free end (121) of the texture, the reinforced area comprising weft yarns or strands made of second fibers (T1-T4) different from the first fibers, the second fibers having an elongation at break greater than that of the first fibers, and in that a first volume rate of second fibers in the reinforced area (140) is greater than a second volume rate of second fibers in the rest of the portion corresponding to the fibrous reinforcement of the airfoil (120) of the blade.

2. The blade according to claim 1, wherein the portion corresponding to the fibrous reinforcement of the airfoil (120) of the blade (10) further comprises a transition area (150) adjacent along the transverse direction (T) to the reinforced area (140) and wherein the weft yarns or strands made of second fibers (T1-T4) are replaced by weft yarns or strands made of first fibers (T5-T8), the weft yarns or strands made of second fibers (T1-T4) gradually exiting from the fibrous texture in the transition area at offset positions along the transverse direction (T), said weft yarns or strands made of second fibers being gradually replaced by weft yarns or strands made of first fibers (T5-T8) at the level of the offset exit positions of the weft yarns or strands made of second fibers.

3. The blade according to claim 2, wherein the transition area (150) extends transversely over a length (L4) comprised between 10 mm and 100 mm.

4. The blade according to any one of claims 1 to 3, wherein the volume rate of second fibers in the reinforced area (140) decreases as moving away from the free end (121) of the fibrous texture along the longitudinal direction (L).

5. The blade according to any one of claims 1 to 4, wherein the first length (L1) is less than or equal to 100 mm.

6. The blade according to any one of claims 1 to 5, wherein the second length (L2) is less than or equal to 50% of the width (L3) of the fibrous texture measured along the transverse direction (T) at the level of the free end (121) of the texture.

7. The blade according to any one of claims 1 to 6, wherein the first fibers are made of carbon, and the second fibers are made of a material chosen among the following: glass, basalt, aramid or polyester.

8. The blade according to any one of claims 1 to 7, wherein the first volume rate is of at least 30%.

9. The blade according to any one of claims 1 to 8, wherein the blade is a fan blade.

10. An aeronautical turbomachine (1) comprising a fan (2) including a rotary disk (8) and a plurality of blades (10) according to claim 9 mounted on the rotary disk.

11. A method for manufacturing a turbomachine (1) blade (10) made of composite material comprising a fibrous reinforcement densified by a matrix and formed by a fibrous texture (100), the texture being in one piece and being obtained by three-dimensional weaving between a plurality of warp yarns or strands made of first fibers extending along a longitudinal direction (L) and a plurality of weft yarns or strands made of first fibers extending along a transverse direction (T), the texture comprising a blade root portion (110) and a blade airfoil portion (120) extending between the blade root portion and a free end (121) of the fibrous texture, the texture extending along the transverse direction (T) between a first edge (101) corresponding to a leading edge (13) of the blade and a second edge (102) corresponding to a trailing edge (14) of the blade, characterized in that the blade airfoil portion (120) has a reinforced area (140) extending along the longitudinal direction (L) from the free end (121) of the fibrous texture over a first length (L1) less than or equal to 20% of the length (L0) of the fibrous texture measured in the longitudinal direction, and along the transverse direction (T) from the second edge (102) over a second length (L2) less than or equal at 75% of the width (L3) of the fibrous texture measured in the transverse direction at the level of the free end of the texture, the reinforced area comprising weft yarns or strands made of second fibers (T1-T4) different from the first fibers, the second fibers having an elongation at break greater than that of the first fibers, and in that a first volume rate of second fibers in the reinforced area (140) is greater than a second volume rate of second fibers in the rest of the blade airfoil portion (120) of the fibrous texture.

12. The method according to claim 11, wherein the blade airfoil portion (120) further comprises a transition area (150) adjacent along the transverse direction (T) to the reinforced area (140) in which the weft yarns or strands made of second fibers (T1-T4) are replaced by weft yarns or strands made of first fibers (T5-T8), the method comprising the gradual exit of the weft yarns or strands made of second fibers (T1-T4) in the transition area (150) at offset positions along the transverse direction (T) and the insertion of weft yarns or strands made of first fibers (T5-T8) as a replacement for the weft yarns or strands made of second fibers at the level of the offset exit positions of the weft yarns or strands made of second fibers. I