Fiber preform with reinforcement formed by layers of unidirectional yarns

Abstract

The invention relates to a fiber preform (10) for a guide blade of a gas turbine engine, wherein the preform (10) comprises two fiber parts (14) forming the airfoil of the blade and defining an inner volume (16) between them, and wherein each fiber part has at least one vibration-damping fiber reinforcement (19a; 19b) comprising one or more unidirectional yarn layers (191a; 191b) and present in the inner volume.

Description

Technical Field

[0001] The invention relates to a fiber preform intended to form a reinforcement for a turbine blade or vane and having arranged in its internal volume one or several fiber reinforcements formed by one or several layers of unidirectional yarns, making it possible to damp vibration modes in operation. The invention also aims at providing a method for manufacturing a turbine blade or vane, the method comprising: forming a matrix in the pores of the fiber preform. Background Art

[0002] Aircraft parts are usually made of composite materials, including fiber reinforcements and a matrix present in the pores of the reinforcements, with the purpose of reducing mass while maintaining good mechanical properties. Fiber reinforcements can be obtained by three-dimensional weaving or by layered stacking of two-dimensional fabrics. In particular, known document US2013017093, which describes an aircraft propeller wing including fiber reinforcements, the fiber reinforcements include two fiber parts that form an aerodynamic profile and define an internal volume between them, and there is a lower density structural insert in the internal volume. This solution makes it possible to further reduce mass while maintaining satisfactory mechanical properties. There has been a problem of reducing mass and maintaining mechanical properties by using composite materials instead, especially for turbine blades or blades, especially for outlet guide vanes (OGV) or straighteners that are subjected to significant mechanical loads in operation. Known document EP 2781694, which discloses a blade made of composite materials.

[0003] It is desirable to provide a turbine blade or vane made of a composite material having reduced mass while having optimized mechanical strength, in particular with respect to the vibration stresses imposed on the component in operation. Summary of the invention

[0004] The invention relates to a fiber preform for a turbine blade or vane, said fiber preform comprising two fiber portions which form the aerodynamic profile of the blade or vane and define an internal volume between them,

[0005] Each fiber portion has at least one fiber vibration-damping reinforcement element, which includes one or several unidirectional layers of yarns and is present in the inner volume.

[0006] For the sake of brevity, the expression "fiber vibration damping reinforcement" will be referred to as "fiber reinforcement" hereinafter.

[0007] Vibratory stresses in turbine operation can induce undesirable modes in the operating blades or vanes. Figure 1The diagram illustrates the displacement of a fiber portion 14 forming the aerodynamic profile of an outlet guide vane made of composite material under the influence of vibrations encountered in operation at four consecutive moments from top to bottom. The fiber portions 14 vibrate in antiphase with a change in the distance between these portions 14, and the inventors believe that these portions can damage the components and / or negatively affect the performance of the engine through a change in the geometry of the aerodynamic profile associated with a change in the modal deformation within the operating range. In response to this problem, the invention proposes the incorporation of fiber reinforcements that make it possible to counteract the antiphase vibrations of the fiber portions and their relative displacements and to couple their movements, in particular at the level of the vibration antinodes. The use of unidirectional layer yarns makes it possible to provide the required stiffness in order to significantly damp problematic vibration modes in operation, while limiting the disturbances defined by the fabric of the fiber portions in order to reduce the risk of the reinforcements causing undesirable fabric modifications that could lead to material weakening.

[0008] In an exemplary embodiment, the at least one fiber reinforcement extends in a radial direction of the preform.

[0009] As a variant, the at least one fiber reinforcement extends in the axial direction of the preform.It should be noted that it does not depart from the framework of the invention if the fiber preform has a fiber reinforcement extending in the radial direction and another fiber reinforcement extending in the axial direction.

[0010] In one exemplary embodiment, the fiber portion is formed by three-dimensional weaving.

[0011] In particular, the at least one fiber reinforcement may be present on non-interconnected areas, on which the yarns of the unidirectional layer are separated from the corresponding fiber portions, and the yarns of the unidirectional layer or layers may be woven with the corresponding fiber portions outside the non-interconnected areas.

[0012] This feature advantageously helps to optimize the bending stiffness of the blade or blade, which is particularly advantageous for some applications, such as outlet guide vanes.

[0013] As a variant, the at least one fiber reinforcement is added to each fiber portion.

[0014] In an exemplary embodiment, the at least one fiber reinforcement extends through the inner volume from one fiber portion to another fiber portion.

[0015] This feature helps to further improve the damping of problematic vibration modes in operation, such as the eigenmodes of the membrane.

[0016] In an exemplary embodiment, each fiber portion has at least two fiber vibration-damping reinforcements, each fiber vibration-damping reinforcement comprising one or several unidirectional layers of yarns and being present in different areas of the inner volume.

[0017] This feature helps to further improve the damping of problematic vibration modes in operation.

[0018] In particular, each fiber portion may have: a first fiber reinforcement extending in the radial direction and present in a region defined by a plane of the equations X1=0.15*C and X2=0.45*C; and a second fiber reinforcement extending in the radial direction and present in a region defined by a plane of the equations X3=0.50*C and X4=0.80*C, wherein C refers to the chord length of the blade or blade preform and the coordinates X1, X2, X3 and X4 are measured in the axial direction with the leading edge as the origin.

[0019] Such an example constitutes a first example of a specific arrangement making it possible to optimize the damping of problematic vibration modes in operation.

[0020] In particular, each fiber portion may have: a first fiber reinforcement extending in the radial direction and present in a region defined by a plane of equations X5=0.10*C and X6=0.40*C; a second fiber reinforcement extending in the radial direction and present in a region defined by a plane of equations X7=0.35*C and X8=0.65*C; and a third fiber reinforcement extending in the radial direction and present in a region defined by a plane of equations X9=0.60*C and X10=0.90*C, wherein C refers to the chord length of the blade or blade preform, and the coordinates X5, X6, X7, X8, X9 and X10 are measured in the axial direction with the leading edge as the origin.

[0021] Such an example constitutes a second example of a specific arrangement making it possible to optimize the damping of problematic vibration modes in operation.

[0022] The two examples of arrangements described above are applicable to various blade or paddle geometries, in particular whether they are moving or stationary. However, for blades or paddles with a reduced chord length, the first arrangement may be advantageous.

[0023] In an exemplary embodiment, the fiber preform is a preform of an outlet guide vane.

[0024] The invention also relates to a turbine blade or vane comprising a fiber preform as described above and a matrix present in the pores of the fiber preform.

[0025] The blade or vane may be an aircraft turbine blade or vane.

[0026] The invention also relates to a turbine, comprising the turbine blade or vane described above. The turbine may be an aircraft turbine.

[0027] The invention also relates to a method for manufacturing a turbine blade or vane made of a composite material, the method comprising at least:

[0028] - forming a fiber preform as described above, and

[0029] - Forming a matrix in the pores of the fiber preform.

[0030] In one exemplary embodiment, a construction insert made of a volatile material is present in the interior volume of the preform, and the method comprises eliminating the construction insert after forming the matrix.

[0031] In this case, a hollow blade or paddle made of composite material with an empty internal volume is obtained. Of course, there is no departure from the framework of the invention if the forming insert is not intended to be eliminated but to remain in the blade or paddle (for example, in order to reduce its mass compared to a monolithic part without internal volume). BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 Schematically represented at four consecutive moments (from top to bottom) is the anti-phase displacement of the fiber portion of an outlet guide vane outside the invention for a vibration mode in operation.

[0033] Figure 2 An example of an outlet guide vane according to the invention is represented schematically and partially.

[0034] Figure 3 Schematically shows Figure 2 The cross section of the blade along III-III.

[0035] Figure 3A Schematically and partially represents the Figure 2 and Figure 3 The fiber reinforcement of the blade extends along the height.

[0036] Figure 4 A variant of an outlet guide vane according to the invention is schematically represented in cross section.

[0037] Figure 5 Schematically shows Figure 4 Detail of a blade showing one example of the arrangement of the yarns of the unidirectional layers of the fiber reinforcement relative to the fiber sections.

[0038] Figure 6 Schematically shows Figure 5A variant of FIG. 4 shows another example of an arrangement of the yarns of a unidirectional layer of a fiber reinforcement relative to the fiber portion.

[0039] Figure 7 Schematically shows Figure 4 A variant of a blade in which the fiber reinforcement passes through the inner volume and extends from one fiber portion to another fiber portion.

[0040] Figure 8 A variant of an outlet guide vane according to the invention is shown schematically and partially.

[0041] Fig. 9 A further variant of an outlet guide vane according to the invention is schematically represented.

[0042] Fig.10 An example of a flow chart of a method for manufacturing a component according to the invention is schematically represented. DETAILED DESCRIPTION

[0043] The application of the invention to outlet guide vanes will be described below and in the accompanying drawings. However, the invention also applies to other examples of turbine blades or blades, such as fan blades, compressor blades or turbine blades. It should be particularly noted that the invention can be applied to static turbine blades as well as turbine blades, for example, rotating turbine blades.

[0044] A description of the invention is also provided below, which applies to the case of a fiber preform formed by three-dimensional weaving, but deviates from the framework of the invention when the preform is obtained by other techniques (for example, by stacking of two-dimensional fabric layers or stacking of unidirectional layers).

[0045] Figure 2 An example of an outlet guide vane 1 according to the invention is shown.

[0046] This blade 1 is a static turbine component that makes it possible to "straighten" the airflow at the outlet of the fan in a secondary airflow. The blade 1 comprises an aerodynamic profile 3 capable of directing the airflow towards the downstream of the turbine, and platforms 5 and 7 that define the flow path of the airflow. The profile 3 extends in an axial direction DA between a leading edge 3a and a trailing edge 3b. The leading edge 3a is situated on the upstream side and the trailing edge 3b is situated on the downstream side. The platforms 5 and 7 are spaced apart in a radial direction DR. In a cross section relative to the radial direction DR, the profile 3 has a curved shape with a variable thickness between its leading edge 3a and its trailing edge 3b, as Figure 3 Schematically represented.

[0047] The blade 1 is made of composite material and comprises a fiber preform 10 obtained by three-dimensional weaving, which is densified by a matrix present in its pores. The fiber preform 10 of the turbine component 1 corresponds to its fiber reinforcement 10 and defines an aerodynamic profile. In the illustrated example, the fiber preform 10 is in the shape of the blade 1 and is formed by three-dimensional weaving of a first yarn and a second yarn. The formation of the fiber preform 10 initially comprises: forming a fiber blank by three-dimensional weaving with the help of a jacquard-type loom, on which bundles of weft yarns have been arranged in multiple layers, the weft yarns being connected by warp yarns. "Three-dimensional weaving" or "3D weaving" as used herein means a fabric in which at least some of the warp yarns interconnect the weft yarns on several weft yarn layers. However, it should be noted that within the framework of the present invention, the first yarn can be a warp yarn and the second yarn can be a weft yarn, and vice versa, and the roles between the warp yarn and the weft yarn are interchangeable. The fiber preform can be woven "interlocking", that is to say three-dimensionally, with each layer of first yarn interconnecting several layers of second yarn with all yarns of the same column of first yarns having the same movement in the weaving plane. If another three-dimensional weaving is implemented to form the preform, it does not deviate from the framework of the invention. The materials of the first yarn and the second yarn are selected according to the application, and the first yarn and the second yarn can be made of carbon or ceramic materials, such as silicon carbide or oxide ceramics.

[0048] During the weaving of the fiber blank corresponding to the illustrated preform, non-interconnection is performed between two consecutive second yarn layers on the non-interconnected area 12. This non-interconnection makes it possible to define two non-interconnected fiber parts 14 that are not woven together on the non-interconnected area 12, which can be spaced apart from each other. The fiber parts 14 define an internal volume 16 between them, which is in the form of a bag 16 or a cavity 16 here. In particular, in the non-interconnected area 12, no yarn layer from a fiber part 14 is woven with a yarn layer from another fiber part 14. In the non-interconnected area 12, no yarn is simultaneously connected by weaving a yarn layer from a fiber part 14 with a yarn layer from another fiber part 14. The fiber part 14 can form a fiber sheath with a relatively thin thickness, for example, a thickness less than or equal to 10 mm, in particular included between 2 mm and 10 mm. In the illustrated example, the fiber parts 14 are each obtained by three-dimensional weaving.

[0049] Here, the non-interconnected area 12 extends between a first axial end 12a located on the side of the leading edge 3a and a second axial end 12b located on the trailing edge 3b. The non-interconnected area 12 may extend over at least 50%, for example at least 75%, of the dimension of the preform (e.g., its chord), which corresponds to the distance between the leading edge 3a and the trailing edge 3b. In the illustrated example, the non-interconnected area 12 extends substantially over the entire height of the fiber preform 10, but if it extends only over a portion of this height, it does not deviate from the framework of the invention. The weaving is continuous outside the non-interconnected area 12 so as to connect the fiber portions 14 and form a single piece of fabric. Here, the leading edge 3a is continuously woven so as to connect the two fiber portions 14 by weaving in the weaving area 15. This continuous weaving at the level of the leading edge 3a is conducive to enhancing its resistance to possible impacts. Here, the trailing edge 3b is also continuously woven so as to connect the two fiber portions 14 by weaving in the weaving area 11. As a variant, the fiber portions 14 can be connected by means other than weaving on the trailing edge 3b. In the example shown, a radial non-interconnection can also be carried out so that the fiber reinforcement of the platforms 5 to 7 is formed from the fiber reinforcement of the profile 3 .

[0050] The internal volume 16 defined by the fiber portion 14 is intended to accommodate a structural insert 18 before the formation of the matrix. The insert 18 gives the fiber preform, in particular the aerodynamic profile 3, the desired shape. In the illustrated example, the structural insert 18 is introduced through the radial ends of the fiber preform, which belong to the non-interconnected region 12. In the preform, the fiber portion 14 surrounds the structural insert 18. Here, the structural insert 18 is illustrated as being made as a whole, but if it is composed of several different elements, it does not deviate from the framework of the invention. The structural insert 18 can be made by molding or machining in a block of material. Here, the structural insert 18 includes ends 18a and 18b, which are rounded to the shape of the leading edge 3a and the trailing edge 3b, respectively. The structural insert 18 can also include an intermediate portion 18c between the ends 18a and 18b, which is shaped as at least a portion of the inner and outer sides of the blade 1.

[0051] According to the corresponding Figure 2 and Figure 3 In a first example, the blade 1 intended to be installed in a turbine also comprises a structural insert 18. In this case, it is preferred to choose a structural insert 18 with a density lower than that of the fiber portion 14 densified by the matrix, in order to reduce the weight of the component. The structural insert 18 may be formed of a porous material, such as a foam or a honeycomb material, as described, for example, in document WO 2011 / 083250. The structural insert 18 may be rigid so as not to deform during operation. According to the embodiment corresponding to Figure 4In a second example, the blade intended to be installed in a turbine is hollow, the internal volume 16 being empty. In this case, the construction insert 18 introduced to form the preform is removable or made of volatile material and is eliminated after densification by the matrix.

[0052] As mentioned above, fiber reinforcements have been integrated into the preform in order to improve the resistance of the blade to vibration stresses in operation, thereby increasing its life. Details related to these fiber reinforcements are described below according to several exemplary embodiments.

[0053] therefore, Figure 3 , Figure 3A and Figure 4 A first example of a fiber reinforcement that can be used within the framework of the present invention is illustrated. Figure 3 and Figure 3A The situation and Figure 4 The cases of the blade 16 differ only in that the insert 18 is present or not in the blade. In the illustrated example, each fiber portion 14 has two fiber reinforcements 19a-19b, which are present in different areas of the inner volume 16. However, the invention is not limited to this precise number of reinforcements. According to a variant, each fiber portion can have more than two fiber reinforcements, evenly spaced or unevenly spaced, for example at least three or four fiber reinforcements. As a variant, each fiber portion has only one fiber reinforcement.

[0054] Each fiber reinforcement 19a-19b is formed by several unidirectional layers of yarns 191a-191b, that is to say, by several layers of yarns 191a-191b extending essentially in the same direction. If the fiber reinforcement comprises only one unidirectional layer, this does not deviate from the framework of the invention. The yarns 191a-191b are not woven or interconnected in each fiber reinforcement 19a-19b. The yarns 191a-191b are present in the internal volume 16, on the inner surface SI of the fiber portion 14 that defines this internal volume 16. The illustrated example relates to the case of fiber reinforcements 19a-19b, whose yarns 191a-191b extend in the radial direction DR. Orientation of the unidirectional layers in the axial direction DA is also possible and will be described below in conjunction with Fig. 9 Discuss. Figure 3 and Figure 4 In the example of FIG. 1 , the fiber reinforcements 19a-19b form reliefs protruding from the fiber portion 14 in the internal volume 16. The yarns 191a-191b are arranged in each reinforcement 19a-19b so as to provide the reinforcement with a variable thickness, wherein the maximum thickness may be located in the area of ​​the maximum relative displacement of the fiber portion 14 associated with the vibration mode of the blade in operation.

[0055] A person skilled in the art will appreciate that the number and positioning of the reinforcements 19a-19b depends on the components and the vibration stresses encountered in operation, and will be able to seek a compromise between the desired damping effect and quality control of the blade incorporating the reinforcements.

[0056] To optimize damping, it is possible to position each fiber reinforcement 19a-19b in a zone comprising an antinode of the vibration mode and defined by a plane whose position corresponds to an amplitude of the relative displacement of the fiber portion 14 equal to 20% of the amplitude of said antinode.

[0057] According to one example, each fiber portion 14 may have: (i) a first fiber reinforcement 19a, which is present in a region defined by planes P1 and P2, respectively, of the equations X1=0.15*C and X2=0.45*C, and (ii) a second fiber reinforcement 19b, which is present in a region defined by planes P3 and P4, respectively, of the equations X3=0.50*C and X4=0.80*C, wherein C refers to the chord length of the blade or blade or the chord length of the preform of the blade or blade, and the coordinates X1, X2, X3 and X4 are measured along the axial direction DA by taking the leading edge 3a as the origin. Most (more than 50%), if not all, of the yarns 191a of the first fiber reinforcement 19a may be present between planes P1 and P2. Most (more than 50%), if not all, of the yarns 191b of the second fiber reinforcement 19b may be present between planes P3 and P4.

[0058] It will be noted that the fiber reinforcements present on two different fiber portions 14 may face each other (in the illustrated example, the first fiber reinforcement 19a and the second fiber reinforcement 19b face each other). These fiber reinforcements 19a or 19b may be present on the same plane orthogonal to the axial direction DA.

[0059] The yarns 191a-191b of the unidirectional layers (or reinforcements 19a and 19b) may each extend over at least 50% or even over at least 75% of the height H of the fiber preform or blade or paddle. Unless otherwise stated, the height of the blade or paddle is measured in the radial direction DR.

[0060] According to an example and Figure 3AAs shown, yarns 191a-191b can extend at least from plane Q1 to plane Q2, where the equations of planes Q1 and Q2 are Y1=0.1*H and Y2=0.9*H, respectively, possibly Y1=0.05*H and / or Y2=0.95*H, H refers to the height of the blade or blade or the height of the preform of the blade or blade, and coordinates Y1 and Y2 are measured along the radial direction DR by taking the inner radial end of the blade or blade or the inner radial end of the blade or blade preform as the origin.

[0061] Now we will describe Figure 5 and Figure 6 Two variants of integrating fiber reinforcements 19a-19b into the fabric of the fiber preform of the blade are shown. These variants apply equally regardless of the number or position of the reinforcements. Figure 5 In the example illustrated in FIG. 1 , the yarn 191a can be woven together with the fiber portion 14 in the woven area 194 and separated from the fiber portion 14 in the non-interconnected area 190. The non-interconnected area 190 is located between the woven areas 194. The woven areas 194 can form a single piece of fabric. The non-interconnection 190 is here carried out in the radial direction DR, but the same principle still applies to the case of a reinforcement extending in the axial direction DA as described below. Therefore, in Figure 5 In the example of , the non-interconnected area 190 is made during the weaving of the blank so as to withdraw the yarn 191a and form the reinforcement 19a. Therefore, the integration of the reinforcement does not require any additional steps after weaving. In this case, the insert 192 can be positioned to hold the yarn 191a in place during the formation of the matrix, which insert can preferably be made of a volatile material so as to be eliminated after the formation of the matrix. Figure 6 In a variant of the present invention, the yarns 191a are added to the corresponding fiber portions 14 after their formation. They can be retained by gluing or mechanically retained before the matrix is ​​formed, for example. Figure 5 and Figure 6 The diagram shows the yarn 191a of the reinforcement member 19a, but this is of course applicable to any reinforcement member, and in particular, remains applicable to the reinforcement member 19b.

[0062] Combination Figures 3 to 6 , the example just described relates to fiber reinforcements 19a - 19b which do not extend from one fiber portion 14 to another. Figure 7 A variant is illustrated in which the fiber reinforcements 19c and 19d comprise yarns 191c-191d of unidirectional layers extending from one fiber portion 14 to the other fiber portion 14 through the internal volume 16. Depending on the compromise sought between damping vibrations and controlling the mass of the blade, a person skilled in the art will tend to use a fiber reinforcement such as Figure 7 The through reinforcement shown or Figure 3 and Figure 4 The use of through reinforcements 19c and 19d is advantageous for large blades or paddles such as fan blades. For smaller geometries, Figure 3 and Figure 4 Non-through reinforcements of the type shown may be advantageous. Figure 7 The situation is illustrated without a construction insert 18 , but according to a variant not illustrated, a construction insert may be present in several parts in the internal volume 16 .

[0063] Just combined Figures 3 to 7 An example has been described in which each fiber portion 14 has two fiber reinforcements. Figure 8 The example in relates to a variant in which each fiber portion 14 has three fiber reinforcements.

[0064] exist Figure 8 In the example of, each fiber part 14 has three fiber reinforcements 19e, 19f and 19g, each reinforcement can have the structure as described above. According to one example, each fiber part 14 can have: (i) a first fiber reinforcement 19e, which exists in the area defined by planes P5 and P6 of equations X5=0.10*C and X6=0.40*C, respectively, (ii) a second fiber reinforcement 19f, which exists in the area defined by planes P7 and P8 of equations X7=0.35*C and X8=0.65*C, respectively, and (iii) a third fiber reinforcement 19g, which exists in the area defined by planes P9 and P10 of equations X9=0.60*C and X10=0.90*C, respectively, where C refers to the chord length of the blade or blade or the chord length of the preform of the blade or blade. Coordinates X5, X6, X7, X8, X9, and X10 are measured along the axial direction DA by taking the leading edge 3a as the origin.

[0065] According to an example, the following characteristics can also be verified:

[0066] the yarns of the unidirectional layer of the first reinforcement 19e may extend at least from a plane Q3 to a plane Q4, wherein planes Q3 and Q4 respectively have the equations Y3=0.2*H and Y4=0.7*H, wherein Y3 may vary between 0.00*H and 0.40*H and / or Y4 may vary between 0.50*H and 0.90*H,

[0067] the yarns of the unidirectional layer of the second reinforcement 19f may extend at least from a plane Q5 to a plane Q6, wherein planes Q5 and Q6 respectively have the equations Y5=0.1*H and Y6=0.9*H, wherein Y5 may vary between 0.05*H and 0.1*H and / or Y6 may vary between 0.90*H and 0.95*H, and

[0068] the yarns of the unidirectional layer of the third reinforcement 19g may extend at least from a plane Q7 to a plane Q8, wherein the planes Q7 and Q8 are respectively the equations Y7=0.3*H and Y8=0.7*H, wherein Y7 may vary between 0.10*H and 0.50*H and / or Y8 may vary between 0.50*H and 0.90*H,

[0069] Wherein H is the height of the blade or blade or the height of the blade or blade preform, and the coordinates Y3, Y4, Y5, Y6, Y7 and Y8 are measured along the radial direction DR by taking the inner radial end of the blade or blade or the inner radial end of the blade or blade preform as the origin.

[0070] Fig. 9 The case where the fiber reinforcement 19h extends in the axial direction DA of the preform is shown.Similar to what is described above, it is possible to have several fiber reinforcements extending in the axial direction DA and arranged at different heights of the blade or blade preform.

[0071] In order to optimize damping, each fiber portion 14 may have: at least one fiber reinforcement 19h present in the area defined by the planes P5 and P6 defined above, and / or at least one fiber reinforcement 19h present in the area defined by the planes P7 and P8 defined above, and / or at least one fiber reinforcement 19h present in the area defined by the planes P9 and P10 defined above. As a variant, each fiber portion 14 may have: at least one fiber reinforcement 19h present in the area defined by the planes P1 and P2 defined above, and / or at least one fiber reinforcement 19h present in the area defined by the planes P3 and P4 defined above. As shown, the fiber reinforcement 19e may extend over more than 50% of the chord length of the blade or blade or the chord length of the preform.

[0072] Different possible structures of blades or propellers and blade or propeller preforms according to the invention have just been described. The following description focuses on details related to the method for manufacturing a blade or propeller that can be implemented within the framework of the invention.

[0073] Fig.10 is a flow chart of an example of a method according to the invention. In a first step E10, a fiber blank of a blade or a paddle is obtained. This blank can be obtained by three-dimensional weaving or by layered stacking of two-dimensional fabrics or unidirectional layers. This blank comprises the above-mentioned fiber reinforcements. As mentioned above, these reinforcements can be formed during the weaving of the blank by performing withdrawal of the yarns 191a on the non-interconnected areas 190 ( Figure 5 example), or integrated by adding them to the fiber part after the blank is obtained ( Figure 6). The blank is then formed by introducing a structural insert 18 into the internal volume 16 (step E20). The fiber portion 14 surrounds the structural insert 18 and takes its shape to define an aerodynamic profile. The structural insert 18 may be intended to be eliminated after the formation of the matrix to obtain a hollow blade or blade, or to be present in a blade or blade intended to be installed in a turbine. Once the blank is shaped and the structural insert 18 has been introduced, a matrix is ​​formed in its pores by methods known per se (step E30). For example, in the case of a component made of an organic matrix composite material, the formation of the matrix may include injecting a resin into the pores of the preform and baking it (for example, crosslinking it) to form the matrix. The matrix is ​​formed in the pores of the fiber portion 14 and around the yarns 191a-191d of the unidirectional layer and in the spaces 191a-191d between the yarns. When the matrix is ​​not made of organic material but of ceramic material (for example, in the case where the blade or vane is intended to be installed in a hot part of a turbine, such as in the case of turbine blades), there is no departure from the framework of the invention. In this case, the ceramic matrix can be formed by chemical vapor infiltration (CVI), by melt infiltration (MI) or by polymer impregnation and pyrolysis (PIP). The techniques for forming the matrix are known per se and do not require further detailed explanation.

[0074] After the formation of the base body, if necessary, the structural insert 18 can be eliminated, for example by melting or dissolving with the aid of a solvent (optional step E40), or simply removed. If necessary, the base body is also finished or processed after formation to obtain a blade or vane ready to be installed in a turbine.

[0075] The expression "included between... and..." must be understood as including the boundaries.

Claims

1. A fiber preform for a turbine blade or vane, comprising two fiber parts, which are formed by three-dimensional weaving and form the aerodynamic profile of the blade or vane, and which define an internal volume between them, in, Each fiber portion has at least one fiber vibration damping reinforcement, the at least one fiber vibration damping reinforcement comprising one or several unidirectional layers of yarn and present in the internal volume, the yarns of the one or several unidirectional layers extending substantially in the same direction and not woven or interconnected in each fiber vibration damping reinforcement, and the at least one fiber vibration damping reinforcement present in a non-interconnected area, where the yarns of the unidirectional layer are separated from the corresponding fiber portion, wherein the yarns of the unidirectional layer are woven with the corresponding fiber portion outside the non-interconnected area, or the at least one fiber vibration damping reinforcement is added to each fiber portion.

2. The fiber preform according to claim 1, wherein: The at least one fiber vibration-damping reinforcement extends along a radial direction of the preform.

3. The fiber preform according to claim 1, wherein: The at least one fiber vibration-damping reinforcement extends in the axial direction of the preform.

4. The fiber preform according to any one of claims 1 to 3, wherein: The at least one fiber vibration-damping reinforcement extends through the inner volume from one fiber portion to another fiber portion.

5. The fiber preform according to any one of claims 1 to 3, wherein: Each fiber portion has at least two fiber vibration-damping reinforcements, each fiber vibration-damping reinforcement comprising one or several unidirectional layers of yarns and being present in different areas of the inner volume.

6. The fiber preform according to claim 5, wherein: Each fiber portion has: a first fiber vibration damping reinforcement, which extends in the radial direction and exists in a region defined by a plane (P1; P2) with equations X1=0.15*C and X2=0.45*C; and a second fiber vibration damping reinforcement, which extends in the radial direction and exists in a region defined by a plane (P3; P4) with equations X3=0.50*C and X4=0.80*C, wherein C refers to the chord length of the fiber preform of the blade or blade, and the coordinates X1, X2, X3 and X4 are measured in the axial direction with the leading edge as the origin.

7. The fiber preform according to claim 5, wherein: Each fiber portion has: a first fiber vibration damping reinforcement extending in the radial direction and existing in a region defined by a plane (P5; P6) with equations X5=0.10*C and X6=0.40*C; a second fiber vibration damping reinforcement extending in the radial direction and existing in a region defined by a plane (P7; P8) with equations X7=0.35*C and X8=0.65*C; and a third fiber vibration damping reinforcement extending in the radial direction and existing in a region defined by a plane (P9; P10) with equations X9=0.60*C and X10=0.90*C, wherein C refers to the chord length of the fiber preform of the blade or blade, and the coordinates X5, X6, X7, X8, X9 and X10 are measured in the axial direction with the leading edge as the origin.

8. The fiber preform according to any one of claims 1 to 3, wherein: The fiber preform is a preform of an outlet guide vane.

9. A turbine blade or vane comprising a fiber preform according to any one of claims 1 to 8 and a matrix present in pores of the fiber preform.

10. A method for manufacturing a turbine blade or vane made of a composite material, the method comprising at least: forming a fiber preform according to any one of claims 1 to 8, and A matrix is ​​formed in the pores of the fiber preform.

11. The method according to claim 10, wherein: A construction insert made of a volatile material is present in the internal volume of the preform, and the method comprises eliminating the construction insert after forming the matrix.

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