Method for manufacturing blades made of composite materials with integrated attachment lugs and platforms

Abstract

A method for manufacturing a stationary turbine engine blade made of composite material includes: - forming a fiber preform by three-dimensional or multi-layer weaving, which is divided in its thickness direction into a first part, a second part, and a third part in two unconnected regions located at the longitudinal ends of the fiber preform, the first part being located between the second and third parts, and the first part being connected to the second and third parts by weaving outside the unconnected regions; - forming a preform (110) of the blade to be produced from the fiber preform by: segmenting (104a, 112) of the second part not connected to the first part at each longitudinal end and on either side of the first part (102, 112). The segments (106a, 116a) of the second and third parts are unfolded and shaped to form preform components for platforms of blades to be manufactured at each longitudinal end of the fiber preform. The segments (102a, 112a) of the first part, which are not interconnected with the segments (104a, 114a, 106a, 116a) of the second and third parts, extend along the longitudinal axis (X) to form preform components for attachment lugs of components to be manufactured at each longitudinal end of the fiber preform. The preforms are densified by a mold to obtain fixed turbine blades made of composite materials and having integrated platforms and attachment lugs at each longitudinal end.

Description

Technical Field

[0001] This invention relates to the general field of stator blades for gas turbine aircraft engines of the "OGV" ("outlet guide vane") type. Background Technology

[0002] In the field of aero-engines, exit guide vanes can be made of composite materials that provide drag equal to or greater than that of metals but with a smaller total mass. Document EP 3 186 486 describes a straightener guide vane made of composite material for a gas turbine engine, comprising a matrix-densified fiber reinforcement formed as a single component by three-dimensional weaving with the blade and attaching lugs extending from the inner and outer radial ends of the blade to opposite sides of the blade.

[0003] The exit guide vane must immediately provide aerodynamic guidance for the air; this is the most important function of its geometry and provides the structural function of the component, namely, transmitting engine forces between the hub and the strut. For this purpose, the vane is equipped with inner and outer platforms to define the air path and transmit forces.

[0004] In addition, the blades must be able to provide these two main functions after being subjected to external attacks (residues ingested by birds, hail, erosion, etc.).

[0005] Because the exit guide vanes are in the static load path, they are subjected to tensile, compressive, torsional, and bending loads under various conditions, as well as all possible combinations thereof. Therefore, it is important that the attachment of these blades allows for uniform behavior regardless of the direction and type of stress.

[0006] The lug attachment extends at an angle substantially perpendicular to the longitudinal axis of the leaf, corresponding to the direction of the continuous warp yarns. Although composite components exhibit very good mechanical properties in the fiber direction, these properties may decrease in other directions. However, lug attachments under compression require operation in the suboptimal direction of the composite material.

[0007] Studies have been conducted to analyze the mechanical drag of an exit guide vane attached via a lug fixed to the blade. Results indicate a systematic stress concentration at the fillet between the lug and the blade, which could lead to initial cracking, matrix microcracks, or fracture in the composite material at this location.

[0008] However, there is a need for an exit guide vane made of composite material that includes a combined platform that does not have a critical area at its attachment point with other components of the engine. Summary of the Invention

[0009] For this purpose, the present invention provides a method for manufacturing stationary turbine engine blades made of composite materials, the method comprising:

[0010] - A fiber preform is formed by three-dimensional or multi-layer weaving between multiple warp and weft layers, having a longitudinal axis corresponding to the longitudinal axis of the blade to be produced. The fiber preform extends between a first longitudinal end and a second longitudinal end. The fiber preform is divided into a first part, a second part, and a third part in its thickness in two non-interconnected regions located at the longitudinal ends of the fiber preform, respectively. The first part is located between the second and third parts and is connected to the second and third parts by weaving outside the non-interconnected regions.

[0011] - A preform of the blade to be manufactured is formed from a fiber preform by the following operations: a segment of the second part and a segment of the third part, which are not interconnected with the first part, are unfolded at each longitudinal end and on either side of the first part; and the unfolded segments of the second and third parts are shaped to form a preform component of a platform for the blade to be manufactured at each longitudinal end of the fiber preform; a segment of the first part, which is not interconnected with the segments of the second and third parts, extends along the longitudinal axis to form a preform component of an attachment winglet for the component to be manufactured at each longitudinal end of the fiber preform.

[0012] - Densification of preforms through a matrix yields fixed turbine blades made of composite materials, each blade having a combined platform and attached blades at each longitudinal end.

[0013] Using the method of the present invention, a blade is obtained having an attachment vane aligned with the longitudinal axis of the blade. This architecture allows for the elimination of any radius between the attachment vane and the blade body. The blade is subjected to traction and compression only at its attachment point, i.e., only in the direction of the continuous warp yarns of the blade's fiber reinforcement. The blade thus obtained exhibits very good drag under stress. Furthermore, the alignment of the attachment vane with the blade body facilitates the merging of non-interconnected portions required to form a platform.

[0014] According to a specific feature of the method of the invention, the warp yarns present in the first portion outside the non-interconnected region are turned into at least one non-interconnected region in the second or third portion. This increases the mechanical resistance of the fiber preform at the bottom of the non-interconnected portion.

[0015] Another specific feature of the method according to the invention is that the thickness of the first portion is greater than the thickness of the second and third portions. This enhances the mechanical drag of the attachment wing, which, unlike the platform, withstands both tensile and compressive forces.

[0016] Another subject of the present invention is a method for manufacturing stationary turbine engine blades made of composite materials, the method comprising:

[0017] - A fiber preform is formed by three-dimensional or multi-layer weaving between multiple warp and weft layers, having a longitudinal axis corresponding to the longitudinal axis of the blade to be produced. The fiber preform extends between a first longitudinal end and a second longitudinal end. In the non-interconnected region extending between its longitudinal ends, the fiber preform is divided into a first part, a second part, and a third part in thickness. The first part is located between the second and third parts. The first part is interconnected with the second and third parts at the longitudinal ends of the fiber preform by weaving to form two interconnected parts.

[0018] - Cut the second and third parts to divide each of the second and third parts into two segments.

[0019] - A preform of the blade to be manufactured is formed from a fiber preform by the following operations: a segment of a second part and a segment of a third part, which are not interconnected with the first part, are unfolded on either side of a first part; and the unfolded segments of the second and third parts are shaped to form a preform component of a platform for the blade to be manufactured near each longitudinal end of the fiber preform; two interconnecting portions between the first, second, and third parts extend along the longitudinal axis to form a preform component of an attachment winglet for the blade to be manufactured at each longitudinal end of the fiber preform.

[0020] - Densification of preforms through a matrix yields blades made of composite materials, which have a combined platform and attached blades at each longitudinal end.

[0021] Using the method of the present invention, a blade is obtained having an attachment vane aligned with the longitudinal axis of the blade. This architecture allows for the elimination of any radius between the attachment vane and the blade body. Therefore, the blade functions only under traction and compression at its attachment point, i.e., only in the direction of the continuous warp yarns of the blade's fiber reinforcement. The blade thus obtained exhibits very good drag under stress, with the thickest portion of the blade corresponding to the attachment vane. Furthermore, the alignment of the attachment vane with the blade body facilitates the merging of non-interconnected portions required to form the platform.

[0022] According to a specific feature of the method according to the invention, the warp yarns present in the first portion of at least one interconnected portion are turned into the non-interconnected region in the second or third portion. This increases the mechanical resistance of the fiber preform at the bottom of the non-interconnected portion.

[0023] According to another specific feature of the method according to the invention, the thickness of the first portion is greater than the thickness of the second and third portions. This increases the drag of the blade's blade section, which is the part of the blade most easily exposed to impact.

[0024] The present invention also relates to a fixed turbine engine blade made of composite material, comprising a matrix-densified fiber reinforcement having a blade portion extending along a longitudinal axis and two platforms fixed to the blade portion and respectively present at two longitudinal ends of the blade, characterized in that: the blade further comprises a first attachment vane and a second attachment vane respectively present at each longitudinal end of the blade and extending along the longitudinal axis, and the fiber reinforcement has a three-dimensional or multi-layer weave, the fiber reinforcement comprising a blade preform component, which is divided at each longitudinal end of the blade preform component into two inner or outer platform preform components fixed to the blade preform component and an inner or outer attachment vane preform component fixed to the blade preform component, each inner or outer attachment vane preform component extending along the longitudinal axis between the inner or outer platform preform components.

[0025] According to a specific feature of the method according to the invention, the warp yarns present in the leaf preform component of the fiber reinforcement are diverted into the inner or outer platform preform half.

[0026] According to another specific feature of the method according to the invention, the thickness of the blade preform component of the fiber-reinforced member is greater than the thickness of the inner or outer platform preform half.

[0027] The present invention also relates to a fixed turbine engine blade made of composite material, comprising a matrix-densified fiber reinforcement having a blade portion extending along a longitudinal axis and two platforms fixed to the blade portion and respectively present at two longitudinal ends of the blade, characterized in that: the blade further comprises a first attachment vane and a second attachment vane respectively present at each longitudinal end of the blade and extending along the longitudinal axis, and the fiber reinforcement has a three-dimensional or multi-layer weave, the fiber reinforcement comprising a blade preform component that again encounters at each of its longitudinal ends two inner or outer platform preform halves fixed to the blade preform component to form an inner or outer attachment vane preform component fixed to the blade preform component, each inner or outer attachment vane preform component extending along the longitudinal axis.

[0028] According to a specific feature of the method according to the invention, the warp yarns present in the inner or outer attachment wing component of the fiber reinforcement are diverted into the inner or outer platform preform half.

[0029] According to another specific feature of the method according to the invention, the thickness of the blade preform component of the fiber-reinforced member is greater than the thickness of the inner or outer platform preform half. Attached Figure Description

[0030] [ Figure 1 ] Figure 1 This is a schematic perspective view of a turbine engine blade according to an embodiment of the present invention.

[0031] [ Figure 2 ] Figure 2 It is intended to produce Figure 1 A schematic plan view of the woven fiber preform of the type of blade.

[0032] [ Figure 3 ] Figure 3 yes Figure 2 Side view of the blank,

[0033] [ Figure 4 ] Figure 4 yes Figure 2 The weaving plane of the blank is along Figure 2 An enlarged schematic diagram of the cross-sectional view along plane IV-IV.

[0034] [ Figure 5 ] Figure 5 yes Figure 2 The weaving plane of the blank is along Figure 2 An enlarged schematic diagram of the cross-sectional view of plane VV.

[0035] [ Figure 6 ] Figure 6 It shows that based on Figures 2 to 5 A schematic diagram of an embodiment of a blade preform made of fiber preform.

[0036] [ Figure 7 ] Figure 7 yes Figure 6 A partial sectional view of the blade prefabricated component.

[0037] [ Figure 8 ] Figure 8 This is a schematic perspective view of a turbine engine blade according to another embodiment of the present invention.

[0038] [ Figure 9 ] Figure 9 It is intended to produce Figure 8 A schematic plan view of the woven fiber preform of the type of blade.

[0039] [ Figure 10 ] Figure 10 yes Figure 9 Side view of the blank,

[0040] [ Figure 11 ] Figure 11 yes Figure 9 The weaving plane of the blank is along Figure 9An enlarged schematic diagram of the cross-sectional view in the XI-XI plane.

[0041] [ Figure 12 ] Figure 12 yes Figure 9 The weaving plane of the blank is along Figure 9 An enlarged schematic diagram of the cross-sectional view of plane VV.

[0042] [ Figure 13 ] Figure 13 It shows from Figures 9 to 12 A schematic diagram of the production of blade preforms from fiber blanks.

[0043] [ Figure 14 ] Figure 14 yes Figure 13 A partial sectional view of the blade preform. Detailed Implementation

[0044] Figure 1 The blade 10 is shown schematically, such as the OGV (outlet guide vane) 10 of a secondary flow straightener for an aircraft turbine engine. The blade 10 includes a blade portion 12, an inner platform 14 and an outer platform 16, and an inner attachment wing 15 and an outer attachment wing 17 extending in the longitudinal direction of the blade portion 12 of the blade 10.

[0045] Throughout the text, the terms “inner” and “outer” are used with reference to their radial position relative to the turbine engine axis.

[0046] The outer surface 14b of platform 14 and the inner surface 16a of platform 16 are designed to define the airflow path through the turbine after the blade 10 is assembled into the turbine housing. The inner attachment vane 15 is designed to allow the blade 10 to be attached to the turbine hub via attachment orifice 150, while the outer attachment vane 17 is designed to allow the blade 10 to be attached to the turbine shield via attachment orifice 170.

[0047] The blade 12 extends between platforms 14 and 16 and attachment vanes 15 and 17 to which the blade 12 is fixed. Attachment vanes 15 and 17 are solid elements and do not contain any cavities extending in the longitudinal direction of the blade 12.

[0048] The blade 10 is made of composite material. Its manufacturing includes forming a fiber preform with a shape corresponding to the shape of the blade and densifying the preform through a matrix.

[0049] Figure 2 The fiber preform 101 is shown in a plane, from which the fiber preform of the blade 10 can be formed.

[0050] The blank 101 is obtained by a strip 100 woven in three dimensions (3D) or multiple layers, the strip 100 extending in a general direction D corresponding to the longitudinal direction of the blade to be manufactured. For example, it can be woven using warp yarns extending in direction D; note that it is also possible to weave using weft yarns extending in this direction. Multiple blanks 101 can be woven one after another in direction D. It is also possible to weave several parallel rows of blanks 101 simultaneously.

[0051] exist Figures 2 to 5 In one embodiment, a blank 101 extending along the longitudinal axis X includes first portions 102, 112, second portions 104, 114, and third portions 106, 116 spanning its thickness and located at each of its ends 101a and 101b. Portion 102 is situated between portions 104 and 106. Portion 102 is interconnected with portions 104 and 106 by 3D weaving in a region 120 intended to form a blade, and is not interconnected with portions 104 and 106 at a non-interconnected region 103, which includes a first non-interconnected portion 103a between portions 102 and 104 and a second non-interconnected portion 103b between portions 102 and 106. The non-interconnected portions 103a and 103b extend across the entire width (weft dimension) of blank 101 from end 101a to the bottom of non-interconnected portions 103c and 103d. The bottoms of the non-interconnected portions 103c and 103d extend along the latitudinal direction between the longitudinal edges 101c and 101d of the blank 101.

[0052] Section 112 is located between sections 114 and 116 and is interconnected with sections 114 and 116 by 3D weaving in region 120, which is intended to form the blade. It is not interconnected with sections 114 and 116 in non-interconnected region 105, which includes a first non-interconnected portion 105a between sections 112 and 114 and a second non-interconnected portion 105b between sections 112 and 116. The non-interconnected portions 105a and 105b extend from the end 101b of the blank 101 across the entire width of the blank 101 to the bottom of the non-interconnected portions 105c and 105d. The bottoms of the non-interconnected portions 105c and 105d extend between the longitudinal edges 101c and 101d of the blank 101.

[0053] In a known manner, a non-interconnected section is formed between two warp yarns, deliberately omitting the passage of the weft yarn through the non-interconnected area to join the warp yarns located on either side of the non-interconnected area.

[0054] Figure 4 and Figure 5The planar representation shows an example of 3D braiding with interlocking braids and non-interconnecting portions 105a and 105b, the non-interconnecting portions 103a and 103b being obtained in the same manner as the non-interconnecting portions 105a and 105b. Figure 5 In the diagram, non-interconnected portions are shown by dashed lines. Portion 112 includes multiple warp layers interconnected by 3D weaving (eight in the illustrated example). Portions 114 and 116 each include multiple warp layers interconnected by 3D weaving (four in the illustrated example). Between the non-interconnected region 103 defined by the bottom of non-interconnected portions 103c and 103d and the non-interconnected region 105 defined by the bottom of non-interconnected portions 105c and 105d, the warp layers of portions 102, 112, 104, 114 and 106, 116 are all interconnected in the illustrated example. Figure 4 ).

[0055] After weaving, a fiber preform 110 is formed from the blank 101. More precisely, the segment 120a located at the center of the preform 110 corresponds to the leaf preform component. Segments 104a, 114a and 106a, 116a that are not interconnected with portions 102 and 112 and are present at the longitudinal ends of segment 120a are as follows: Figure 6 The figures shown are unfolded or deployed to form each prefabricated half of platform 14, 16 for segments 104a, 114a adjacent to non-interconnected portions 103a, 105a and segments 106a, 116a adjacent to non-interconnected portions 103b, 105b. The unfolding is produced at the bottom of the non-interconnected portions.

[0056] According to the present invention, segments 102a and 112a, which are intended to form the inner attached wing preform component and the outer attached wing preform component respectively, are retained in positions parallel to the longitudinal direction X of the blank.

[0057] This forms a fiber reinforcement for the blade 10 to be produced, which includes a blade preform component 120a, which is divided at each longitudinal end into two inner or outer platform preform halves 104a, 106a and 114a, 116a fixed to the blade preform component, and inner or outer attached blade preform components 102a, 112a fixed to the blade preform component.

[0058] The fiber preform 110 of the blade to be manufactured is then placed in a forming tool to obtain the desired blade profile and the desired shape of the platform and attached airfoil.

[0059] By such as Figure 1 The blades made of the ceramic matrix composite (CMC) material shown can be manufactured as follows.

[0060] The fiber strip 100 is woven by three-dimensional weaving, comprising, for example, a plurality of fiber blanks 101 oriented in the warp direction, having non-interconnected regions, such as... Figure 2 As shown in the diagram. Ceramic yarns can be used for weaving, particularly yarns made of silicon carbide (SiC), such as those sold by the Japanese company Nippon Carbon under the name "Nicalon". Other ceramic yarns are available, especially refractory oxide yarns, such as yarns made of alumina (Al₂O₃), particularly for oxide-oxide type CMC materials (fiber-reinforced and refractory oxide matrix fibers). Carbon yarns can also be used for CMC materials with carbon fiber reinforcement.

[0061] In known ways, fiber slivers can be treated to remove sizing agents present on the fibers and oxides present on the fiber surface.

[0062] Similarly, in a known manner, a thin embrittlement-relieving interface coating can then be formed on the fibers of the fiber strip via CVI (“chemical vapor infiltration”). The interface material is, for example, pyrolytic carbon (PyC), boron nitride (BN), or boron-doped carbon (BC). The thickness of the formed layer is, for example, between 10 nm and 100 nm to maintain the deformability of the fiber preform.

[0063] The fiber strips are then impregnated with a binding composition, typically a carbon precursor resin or a ceramic precursor resin, diluted in a solvent where applicable. After drying, individual fiber preforms are cut. Each preform is then shaped (e.g., Figure 6 (As shown in the illustration) and placed in a tool for forming the blade preform components, inner and outer platforms, and inner and outer attached blades.

[0064] Next, the resin is cured and then pyrolyzed after the preform is removed from the forming tool to obtain a blade preform solidified by the pyrolysis residue. The amount of solidified resin is chosen to be sufficient but not excessive, such that the pyrolysis residue interconnects the fibers of the preform so that it is manufacturable without tooling assistance while maintaining its shape.

[0065] The second embrittlement-releasing interphase coating can be formed using CVI, for example, made from PyC, BN, or BC. The production of two interphase coatings before and after consolidation is described in document EP2154 119.

[0066] The consolidated preform is then densified using a ceramic matrix, for example, through CVI. The matrix can be made of SiC, or a self-healing matrix comprising a matrix phase of pyrolytic carbon (PyC), boron carbide (B4C), or a ternary Si-BC system, as described in US 5,246,756 and US 5,965,266. Other types of ceramic matrices are conceivable, particularly refractory oxide matrices, such as those made of aluminum, especially for oxide-oxide type CMC materials.

[0067] The blades can also be made from CMO organic matrix composites (any type of fiber preform, whether thermoplastic or thermosetting). In this case, the densification of the fiber preform is achieved in a manner known per se after a liquid process.

[0068] Liquid methods involve impregnating a fiber preform with resin. The preform is placed in a mold, which can be sealed in a sealed manner using a housing having the shape of the final portion. Next, resin (e.g., a thermoplastic or thermosetting resin) is injected into the entire housing to impregnate the entire fibrous portion of the preform.

[0069] Polymerization is accomplished through heat treatment (usually by heating the mold). Since the preform remains in the mold, its shape corresponds to the shape of the part to be produced. The organic matrix can be obtained, in particular, from epoxy resins.

[0070] Once the preform is densified by the matrix, a blade is obtained, whose geometry corresponds to... Figure 1 The final blade 10. Then the inner attachment blade is machined to form the attachment aperture 150 and the outer attachment blade is machined to form the attachment aperture 170.

[0071] According to the features of the invention, the thickness e1 of the first portions 102 and 112 is greater than the thickness e2 of the second portions 104 and 114 and greater than the thickness e3 of the third portions 106 and 116. Figure 3 ).exist Figure 4 and Figure 5 In the example illustrated, the second section 114 and the third section 116 each consist of 4 warp layers, while the first section 112 consists of 8 warp layers. This also applies to the first, second, and third sections 102, 104, and 106. Figure 4 and Figure 5 Not shown in the image.

[0072] The warp yarns in the fiber preform can be straight, i.e., the warp yarns do not cross and the same warp yarns remain present in the first, second, and third sections 102, 104, and 106, outside and inside the non-interconnected areas. According to Figure 7In the variant embodiment illustrated, some warp yarns present in the first portion 112 outside the non-interconnected region 105, here warp yarns C1 and C2, are redirected in the second and third portions 114 and 116 of the non-interconnected region 105. Warp yarns present in the second and third portions 114 and 116 outside the non-interconnected region 105, here warp yarns C3 and C4, can also be redirected in the first portion 112 of the non-interconnected region 105. This increases the mechanical resistance of the fiber preforms at the bottom of the non-interconnected portions 105c and 105d. The same applies. Figure 7 The warp yarns of the first, second, and third sections 102, 104, and 106 are not shown in the diagram.

[0073] Figure 8 A blade 20 according to another embodiment of the invention is shown schematically. The blade 20, such as an OGV (outlet guide vane) of a secondary flow straightener for an aircraft turbine engine, comprises a blade portion 22, an inner platform 24 and an outer platform 26, and inner and outer attachment vanes 25 and 27 extending longitudinally from the blade portion 22 of the blade 20. The outer surface 24b of platform 24 and the inner surface 26a of platform 26 are intended to define the airflow path in the turbine after the blade 20 is assembled into the turbine housing. The inner attachment vane 25 is intended to allow the blade 20 to be attached to the turbine engine hub via attachment orifice 250, while the outer attachment vane 27 is intended to allow the blade 20 to be attached to the turbine engine shroud via attachment orifice 270. The blade portion 22 extends between platforms 24 and 26 and attachment vanes 25 and 27, to which the blade portion 12 is fixed. Attachment vanes 25 and 27 are solid elements and do not contain any cavities extending longitudinally from the blade portion 12.

[0074] The blade 20 is made of composite material. Its manufacturing includes forming a fiber preform with a shape corresponding to the shape of the blade and densifying the preform through a matrix.

[0075] Figure 9 The fiber preform 201 is shown in a plane, from which the fiber preform of the blade 20 can be formed.

[0076] The blank 201 is obtained by a strip 200 woven in three dimensions (3D) or multiple layers, the strip 200 extending in a general direction D corresponding to the longitudinal direction of the blade to be manufactured. For example, it can be woven using warp yarns extending in direction D; note that it is also possible to weave using weft yarns extending in this direction. Multiple blanks 201 can be woven one after another in direction D, and it is also possible to weave several parallel rows of blanks 201 simultaneously.

[0077] exist Figures 10 to 12In one embodiment, the blank 201 extending along the longitudinal axis X includes a first portion 202, 212, a second portion 204, 214, and a third portion 206, 216 spanning its thickness and located at each of its ends 201a and 201b. Portion 202 is situated between portions 204 and 206. Portion 202 is interconnected with portions 204 and 206 by 3D weaving in an interconnected region or portion 220 intended to form an inner attached blade, and is not interconnected with portions 204 and 206 at a non-interconnected region 203, which includes a first interlinking portion 203a between portions 102 and 104 and a second interlinking portion 203b between portions 202 and 206. Non-interlinking portions 203a and 203b extend across the entire width (dimension in the weft yarn) of blank 201 between the bottoms of non-interlinking portions 203c and 203d and the bottoms of non-interlinking portions 203e and 203f. The bottoms of non-interlinking portions 203c, 203d, 203e, and 203f extend along the weft direction between the longitudinal edges 201c and 201d of blank 201.

[0078] Part 212 is located between parts 214 and 216 and is interconnected with parts 214 and 216 by 3D weaving in the interconnection region or part 221, which is intended to form the outer attachment blade of the blade, and is not interconnected with parts 214 and 216 at the non-interconnection region 203, which includes a first non-interconnection region 203a between parts 212 and 214 and a second non-interconnection region 203b between parts 212 and 216.

[0079] In a known manner, a non-interconnected section is formed between two warp layers, deliberately omitting the passage of the weft yarn through the non-interconnected area to interconnect the warp yarns located on either side of the non-interconnected area.

[0080] Figure 11 and Figure 12 The diagram illustrates a 3D example with interlocked and non-interconnected regions 203a and 203b. Figure 12 In the diagram, non-interconnected sections are shown in dashed lines. Section 202 includes multiple warp layers (eight in the illustrated example) connected by 3D weaving. Sections 204 and 206 each include multiple warp layers interconnected by 3D weaving (four in the illustrated example). In interconnected section 220, the warp layers of sections 203, 204, and 206 are all interconnected with each other in the illustrated example. Figure 11 This also applies to sections 212, 214, and 216 in interconnect section 221.

[0081] After weaving, a fiber preform 210 is formed based on the blank 201. More precisely, portions 204 and 214 on one side and portions 206 and 216 on the other side of the non-interconnected regions 203 are separated by making corresponding cuts 207a and 207b. Figure 10 Once parts 204, 214, 206, and 216 are released, segments 204a, 214a, and 206a, 216a of parts 204, 206, 214, and 216 that are not interconnected with parts 202 and 212 are as follows: Figure 13 The components shown are unfolded or deployed to form each prefabricated half for platforms 24 and 26. The unfolding is completed at the bottom of the non-interconnected portion. The segment 220a located at the center of prefabricated part 210 corresponds to the leaf prefabricated component.

[0082] According to the present invention, segments 202a and 212a, which are intended to form the inner attached wing preform component and the outer attached wing preform component respectively, are retained in positions parallel to the longitudinal direction X of the blank.

[0083] This forms a fiber reinforcement for the blade 20 to be produced, comprising a blade preform component 220a, which again encounters at each of its longitudinal ends two inner or outer platform preform halves 204a, 206a; 214a, 216a fixed to the blade preform component to form inner or outer attached blade preform components 202a; 212a fixed to the blade preform component.

[0084] The fiber preform 210 of the blade to be manufactured is then placed in a forming tool to obtain the desired blade profile and the desired shape of the platform and attached airfoil.

[0085] By such as Figure 8 The blades made of the ceramic matrix composite (CMC) material shown can be manufactured according to the previously specified... Figure 1 The blades are manufactured in the manner described above, so for simplicity, they will not be repeated here. Once the preform is densified with the matrix, the blade is obtained, whose geometry corresponds to... Figure 8 The final blade 20. Then the inner attachment vane is machined to form the attachment orifice 250 and the outer attachment vane is machined to form the attachment orifice 270.

[0086] According to one aspect of the invention, the thickness e4 of the first portions 202, 212 is greater than the thickness e5 of the second portions 204, 214 and greater than the thickness e6 of the third portions 206, 216. Figure 11 and Figure 12In the example illustrated, the second section 214 and the third section 216 each include four warp layers, while the first section 212 includes eight warp layers. This also applies to the first, second, and third sections 202, 204, and 206. Figure 11 and Figure 12 Not shown in the image.

[0087] In the same manner as the fiber preform of the previously described blade 10, the warp yarns in the fiber preform can be straight, i.e., the warp yarns do not cross and the same warp yarns remain present in the first, second, and third portions 202, 204, and 206 outside and inside the non-interconnected areas. Figure 14 The variant embodiment illustrated herein includes certain warp yarns, here warp yarn C, present in the first portion 202 outside the non-interconnected region 203. 11 and C 12 The warp yarns, located in the second and third portions 204 and 206 outside the non-interconnected region 203, are turned. Here, warp yarn C is present in the second portion 204 and third portion 206 outside the non-interconnected region 203. 13 and C 14 It can also be turned in the first section 202 at the non-interconnected section 220. This increases the mechanical resistance of the fiber preforms at the bottom of the non-interconnected sections 203c and 203d. This also applies to the warp yarns of the first, second, and third sections 212, 214, and 216. Figure 14 Not shown in the image.

Claims

1. A method for manufacturing a stationary turbine engine blade made of composite materials, the method comprising: - By three-dimensional or multi-layer weaving between multiple warp and weft layers, a fiber preform is formed having a longitudinal axis corresponding to the longitudinal axis of the blade to be produced. The fiber preform extends between a first longitudinal end and a second longitudinal end. The fiber preform is divided into a first part, a second part, and a third part in its thickness into two non-interconnected regions located at the longitudinal ends of the fiber preform, respectively. The first part is located between the second and third parts and is connected to both the second and third parts by weaving outside the non-interconnected regions. - A preform of the blade to be manufactured is formed from a fiber preform by the following operations: a segment of the entire second part and a segment of the entire third part, not interconnected with the first part, are unfolded at each longitudinal end and on either side of the first part; and the unfolded segments of the entire second part and the entire third part are shaped to form a preform component of a platform for the blade to be manufactured at each longitudinal end of the fiber preform; a segment of the first part, not interconnected with the segments of the entire second and third parts, extends along the longitudinal axis to form a preform component of a blade for attaching a fixed turbine engine blade to be manufactured at each longitudinal end of the fiber preform; and - The preform is densified by a matrix to obtain the fixed turbine engine blade made of composite material, the blade having a combined platform and attached blade at each longitudinal end aligned with the longitudinal axis of the blade, wherein the entire area of ​​the fiber preform intended to form the blade portion between the platforms is an interlocked 3D weave formed by continuously interconnecting a first portion of the fiber preform with a second and a third portion of the fiber preform, wherein the thickness of the first portion is greater than the thickness of the second and third portions.

2. The method of claim 1, wherein the warp yarns present in the first portion outside the non-interconnected region are turned into at least one non-interconnected region in the second or third portion.

3. A method for manufacturing stationary turbine engine blades made of composite materials, the method comprising: - By three-dimensional or multi-layer weaving between multiple warp and weft layers, a fiber preform is formed having a longitudinal axis corresponding to the longitudinal axis of the blade to be produced. The fiber preform extends between a first longitudinal end and a second longitudinal end. In the non-interconnected region extending between its longitudinal ends, the fiber preform is divided into a first part, a second part, and a third part in thickness. The first part is located between the second and third parts. The first part is connected to the second and third parts at the longitudinal ends of the fiber preform by weaving to form two interconnected parts. - Cut the second and third parts to divide each of the second and third parts into two segments. - A preform of the blade to be manufactured is formed from a fiber preform by the following operations: two segments of a second part and two segments of a third part, which are not interconnected with the first part, are unfolded on either side of a first part; and the unfolded segments of the second part and the third part, which are not interconnected with the first part, are shaped to form a preform component of a platform for the blade to be manufactured near each longitudinal end of the fiber preform; two interconnecting portions between the first, second, and third parts extend along the longitudinal axis to form a preform component of an attachment fin for the blade to be manufactured at each longitudinal end of the fiber preform; and - The preform is densified through a matrix to obtain a blade made of composite material, the blade having a merged platform and attachment vanes at each longitudinal end aligned with the longitudinal axis of the blade, wherein the entire area of ​​the fiber preform intended to form the attachment vanes at each longitudinal end of the blade is an interlocking 3D weave formed by continuously interconnecting a first portion of the fiber preform with a second and a third portion of the fiber preform. The thickness of the first part is greater than the thickness of the second and third parts.

4. The method of claim 3, wherein the warp yarns present in the first portion of at least one interconnected portion are turned into the non-interconnected region in the second or third portion.

5. A stationary turbine engine blade made of composite material, comprising a matrix dense fiber reinforcement, the blade having a blade portion extending along a longitudinal axis and two platforms fixed to the blade portion and respectively located at two longitudinal ends of the blade, wherein: The blade also includes a first attachment flap and a second attachment flap, respectively located at each longitudinal end of the blade and extending along the longitudinal axis. The fiber reinforcement has a three-dimensional or multi-layered weave between multiple warp layers and multiple weft layers. The fiber reinforcement includes a blade preform component, which at each of the two longitudinal ends and along the thickness of the blade preform component is divided into two inner or outer platform preform halves fixed to the blade preform component and an inner or outer attachment flap preform component fixed to the blade preform component, such that the thickness of the blade preform component between the two platforms of the blade is greater than that of the component fixed to the blade preform component. The thickness of each of the two inner or outer platform preform halves and the thickness of the inner or outer attachment vane preform component fixed to the blade preform component, the inner or outer attachment vane preform component at one of the two longitudinal ends extending along the longitudinal axis between the inner or outer platform preform halves, wherein, in the blade preform of the fiber reinforcement, all the warp yarns of the plurality of warp layers are connected together by the weft yarns of the plurality of weft layers, and wherein, the thickness of the inner or outer attachment vane preform component fixed to the blade preform component is greater than the thickness of each of the two inner or outer platform preform halves fixed to the blade preform component.

6. The blade according to claim 5, wherein the warp yarns are turned into the inner or outer platform preform half.

7. A stationary turbine engine blade made of composite material, comprising a matrix dense fiber reinforcement, the blade having a blade portion extending along a longitudinal axis and two platforms fixed to the blade portion and respectively located at two longitudinal ends of the blade, wherein: The blade also includes a first attachment flap and a second attachment flap, respectively present at each longitudinal end of the blade and extending along the longitudinal axis. The fiber reinforcement has a three-dimensional weave and includes an integral blade preform component, at each of the two longitudinal ends, with two inner or outer platform preform halves fixed to the blade preform component to form an inner or outer attachment flap preform component fixed to the blade preform component. Each inner or outer attachment flap preform component extends along the longitudinal axis at each of the two longitudinal ends. In the blade preform component of the fiber reinforcement, all warp yarns of multiple warp layers pass through multiple weft layers. The weft yarns are connected together, wherein each of the inner or outer attached vane preform components at each of the two longitudinal ends is divided in thickness into the two inner or outer platform preform halves and the blade preform component, such that the thickness of each of the inner or outer attached vane preform components is greater than the thickness of each of the two inner or outer platform preform halves and the thickness of the blade preform component fixed to the two platforms of the blade, and wherein the thickness of the inner or outer attached vane preform component fixed to the blade preform component is greater than the thickness of each of the two inner or outer platform preform halves fixed to the blade preform component.

8. The blade of claim 7, wherein the warp yarns present in the inner or outer attached blade component of the fiber reinforcement are diverted into the two inner or outer platform preform halves.

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