Method for producing vane made of composite material

Abstract

The invention relates to a method for manufacturing a vane made of a composite material, comprising the following steps: (a) continuously stacking a plurality of fibrous layers to form a fibrous blank (200) having a first part and a second part connected to each other in a continuous manner, (b) shaping the fibrous blank (200) by folding along a line (P), forming a lower skin and an upper skin of a fibrous preform (220) of the blade airfoil on both sides of a line (P) at and along which a leading edge of the airfoil or alternatively a trailing edge of the airfoil is positioned; and (d) densifying the fibrous preform (220) with a resin to form a bucket made of a composite material.

Description

Technical Field

[0001] The invention relates to the general field of manufacturing blades for turbomachines, in particular turbomachines for aircraft. Background Art

[0002] The prior art includes in particular documents GB-A-1302857, EP-A1-3542999 and US-A1-4626172.

[0003] Turbines, in particular twin-flow turbines, are known, which include a fan arranged upstream of a gas generator according to the circulation of the gases in the turbine. The gas generator is housed in an inner annular casing, while the fan is housed in an outer annular casing and is usually fixed to a nacelle. The fan generates a main or hot flow, which circulates in a primary channel through the gas generator, and a secondary or cold flow, which circulates in a secondary channel around the gas generator.

[0004] The fan comprises fan blades, each having a free end facing the outer casing, to compress an incident air flow at least in the secondary channel and preferably also in the primary channel.

[0005] Turbine buckets typically include aerodynamically shaped blades. The blades include a pressure side surface and a suction side surface joined together by a leading edge and a trailing edge of the blade. The buckets may be made of metal or composite materials (e.g., organic matrix composites), in particular to reduce the weight of the buckets.

[0006] Commonly used composite materials include fiber preforms embedded in polymer resins. The fiber preforms can be manufactured by three-dimensional (3D) weaving, or can be obtained by stacking (or laminating) and superimposing multiple fiber layers / plies (e.g. in the form of strips or tapes). The resin can be injected into the fiber preform, or the fiber preform can be pre-impregnated with the resin (also known as "prepreg").

[0007] The stacking of the fiber layers can be done manually or automatically by a suitable machine, in particular according to the Automated Fiber Laying (AFP) technology, the Automated Tape Laying (ATL) technology, or the Pick & Place (P&P) system technology.

[0008] One method for manufacturing a blade made of a composite material is to manufacture a pressure side skin from a first fiber preform to form the pressure side of the blade, and then to manufacture a suction side skin from a second fiber preform to form the suction side surface of the blade. The first fiber preform and the second fiber preform are obtained by continuously stacking a plurality of fiber layers. Then, after densification with a polymer resin, the opposite ends of the pressure side skin and the suction side skin are fixed together to form the leading edge and the trailing edge of the blade to obtain the final blade. Another method for manufacturing a blade made of a composite material is to stack fiber folds to manufacture a fiber preform, which forms a skin intended to form the pressure side to the suction side of the blade. The opposite ends of the skin are then fixed together. For example, the ends of one or more skins can be fixed by gluing or directly by polymerization of the resin during densification.

[0009] Fastening the pressure and suction side skins in this way has the disadvantage of being a weak connection that can easily weaken the leading and trailing edges, particularly in the event of a hit or impact from a foreign object during operation. This may generally prevent designers from manufacturing a composite blade by stacking fiber layers.

[0010] To overcome this disadvantage, it may be necessary to stack layers with continuous fibers to form a strong bond between the pressure and suction sides of the blades of the bucket.

[0011] To achieve this, the stacking of fiber layers can be carried out in the form of a spar on a reinforcement support (e.g. a mandrel). However, the aerodynamic shape of the blade (i.e. a twisted shape) may make it difficult (if not impossible) to remove the reinforcement support inside the spar. In particular, during the shaping step (also called "forming") of the spar, it is unreliable to use reinforcement supports that can be broken or disassembled. This is because the breakable or removable support cannot withstand the compaction pressure locally applied to the reinforcement support by the AFP technology deposition head. In addition, some areas of the blade of the wheel blade may be thin (e.g. direct contact between the pressure side skin and the suction side skin to form the trailing edge) to accommodate the reinforcement support. However, the absence of a reinforcement support (i.e. being in a vacuum) may hinder the manufacture of the wheel blade by stacking folded parts, in particular using automated machines (e.g. AFP technology).

[0012] There is therefore a need to optimize the manufacture of blades made of composite materials by stacking fiber layers while ensuring good mechanical resistance of the blades to impacts during operation. Summary of the invention

[0013] The present invention provides a simple, effective and economical solution to this problem.

[0014] The invention proposes a method for manufacturing a blade made of composite material for an aircraft turbine, the blade comprising a blade having a pressure side and a suction side interconnected by a leading edge and a trailing edge, the method comprising the following steps:

[0015] (a) stacking a plurality of fiber layers in succession to form a fiber blank,

[0016] (b) shaping the fiber blank to obtain a fiber preform of a blade, the fiber preform comprising a pressure side skin and a suction side skin joined together, the pressure side skin and the suction side skin being configured to form the pressure side and the suction side of the blade, respectively, and

[0017] (d) densifying the fiber preform with a resin to form a blade made of a composite material.

[0018] According to the invention, the fiber blank comprises a first portion and a second portion which are continuously joined together in step (a).

[0019] Furthermore, step (b) comprises folding the fiber blank along a line extending between the first portion and the second portion to form the pressure side skin and the suction side skin on either side of the fold line.

[0020] The leading edge of the blade or alternatively the trailing edge of the blade is located at and along the fold line, and edges of the pressure side skin and the suction side skin opposite the fold line are joined together to form the leading edge of the blade or alternatively the trailing edge of the blade.

[0021] This solution therefore enables the above-mentioned objectives to be achieved. Generally speaking, the method according to the invention enables us to simplify and optimize the manufacture of blades made of composite material using the stacked fiber layer technology.

[0022] In particular, step (a) of the method enables the fiber layers to be stacked to form a fiber blank with continuous fibers. Step (b) of folding the fiber blank along a folding line brings together the pressure side skin and the suction side skin of the fiber preform and forms the leading edge or alternatively the trailing edge of the blade of the blade at the folding line. Thus, the folding line enables a strong connection area to be formed between the pressure side skin and the suction side skin, because the connection area is formed by continuous fibers.

[0023] Therefore, the blade made of composite material manufactured by this method has strong bonds in particular at the leading edge and / or the trailing edge in order to increase the mechanical strength of the blade in particular in case of impacts or shocks from foreign objects during operation.

[0024] According to the invention, the fiber blank and / or fiber preform is formed on a flat, U-shaped curved or V-shaped curved surface of a support, wherein said surface of the support also comprises a U-shaped protrusion or a V-shaped protrusion configured to define said folding line. The method comprises in step (a) a step (i) of preforming at least a portion of the fiber blank formed on said U-shaped protrusion or V-shaped protrusion of the support.

[0025] This preforming step (i) enables the so-called connection area to be preformed directly on the fiber blank, in particular at the folding line, before the fiber blank is folded in step (b). This facilitates the folding of the fiber blank and controls the dimensions of the connection area between the pressure side skin and the suction side skin. As a result, the mechanical strength of the blade made of composite material is improved (in particular at the leading edge and / or trailing edge).

[0026] In the present application, turbine buckets may be ducted (such as in the case of a fan) or unducted (such as in the case of a propeller of an open rotor type architecture).

[0027] The manufacturing method according to the invention may include one or more of the following features, taken independently of each other or taken in combination with each other:

[0028] - in step (a) or step (b), the fiber blank has a substantially flat and / or U-shaped or V-shaped bend;

[0029] - step (a) is performed manually or by machine;

[0030] - step (d) comprises impregnating the fiber preform with a resin and polymerizing the resin by heat treatment;

[0031] - before step (d), the resin is injected into the fiber preform, or the fiber blank is pre-impregnated with the resin;

[0032] - the resin is thermosetting, such as epoxy resin;

[0033] - the resin is thermoplastic, such as polyetheretherketone, polyaryletherketone or polyetherimide;

[0034] The method comprises a step (c) of adding at least one reinforcing insert into the internal space delimited by the pressure side skin and the suction side skin of the fiber preform, for example the reinforcing insert being made of foam, porous material or composite material.

[0035] --Step (b) is a step for forming a fiber blank;

[0036] - in step (b), folding the fiber blank is carried out by compacting, for example, at a pressure between 300 and 800 Pascals;

[0037] - in step (b), folding the fiber blank is carried out by compacting, for example, under a vacuum between -300 mbar and -900 mbar (i.e., between -30,000 Pascal and -90,000 Pascal); - step (b) is carried out at a predetermined temperature, which may vary depending on the selected resin, for example, in particular in the case of fiber layers pre-impregnated with thermosetting resins, the predetermined temperature being between 30° C. and 100° C.;

[0038] - the method comprises the step (i) of preforming at least a portion of the fiber blank formed on said protruding portion;

[0039] - step (i) is carried out during step (a);

[0040] - the fiber layers each comprise glass fibers, carbon fibers, aramid fibers, polyamide fibers, ceramic fibers, metal fibers, oxide fibers or a mixture of at least two of these fibers;

[0041] - the reinforcement insert comprises a sealed capsule encapsulating the porous material;

[0042] - the porous material of the reinforcing insert is selected from polymer foam, aluminum foam, metal tin phosphor bronze (nida) and / or aramid polymer;

[0043] -Reinforcement inserts can be manufactured by additive manufacturing;

[0044] --The reinforcing insert can be made of thermoplastic structure;

[0045] The invention also relates to a blade made of composite material for an aircraft turbine, which blade is produced by the production method described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The invention will be better understood and other details, features and advantages of the invention will become more apparent from the following description made by way of non-limiting example and with reference to the accompanying drawings, in which:

[0047] - Figure 1 is a schematic half view of an axial section of an aircraft turbine:

[0048] - Figure 2 yes Figure 1 A schematic perspective view of a turbine blade;

[0049] - Figure 3 is used to manufacture according to the present invention Figure 2 A block diagram of a method for manufacturing a blade made of a composite material is shown;

[0050] - Figure 4a is a schematic cross-sectional view of a fiber blank obtained by the manufacturing method of the present invention;

[0051] - Figure 4b yes Figure 4a A schematic cross-sectional view of a folded fiber blank;

[0052] - Figure 5 is a schematic cross-sectional view of a fiber preform obtained by the manufacturing method of the present invention;

[0053] - Figure 6 According to the first embodiment Figure 3 Schematic diagram of some of the steps in the manufacturing method of, in a first embodiment, the method uses a substantially flat support;

[0054] - Figure 7a yes Figure 6 A schematic diagram of a substantially flat support member shown, the support member comprising a protruding portion according to a first variant;

[0055] - Figure 7b yes Figure 6 A schematic diagram of a generally planar support member including a protruding portion in a second variation is shown;

[0056] - Figure 8 According to the second embodiment Figure 3 Schematic diagram of a portion of the steps of a manufacturing method of, in a second embodiment, the method uses a substantially curved support member;

[0057] - Figure 9a yes Figure 8 A schematic diagram of a generally curved support member comprising a protruding portion according to a first variant;

[0058] - Figure 9b yes Figure 8 A schematic diagram of a generally curved support member comprising a protruding portion according to a second variant;

[0059] - Fig.10 According to another embodiment Figure 3 A schematic diagram of some steps in the manufacturing method shown;

[0060] - Fig.11a is a schematic diagram of an axial section of a fiber preform including a reinforcement insert according to a first variant;

[0061] - Fig.11bis a schematic axial cross-sectional view of a fiber preform including a reinforcement insert according to a second variant.

[0062] Elements having the same function in different exemplary embodiments are provided with the same reference numerals in the figures. DETAILED DESCRIPTION

[0063] Generally, in the following description, the terms "longitudinal" and "axial" refer to the orientation of a structural element extending in the direction of a longitudinal axis. The terms "radial" or "vertical" refer to the orientation of a structural element extending in a direction perpendicular to the longitudinal axis. The terms "inner" and "outer" as well as "interior" and "exterior" are used with reference to positioning relative to the longitudinal axis. Thus, a structural element extending along the longitudinal axis comprises an inner surface facing the longitudinal axis and an outer surface opposite the inner surface of the structural element.

[0064] For example, in Figure 1 1 shows a ducted turbine 1, in particular a ducted turbine for an aircraft. The turbine 1 may be a turbojet or a turboprop.

[0065] The turbine 1 extends around a longitudinal axis X. The turbine comprises, from upstream to downstream in a gas flow direction F along the longitudinal axis X, a fan 1a, at least one compressor (e.g. a low-pressure compressor 1b and a high-pressure compressor 1c), a combustion chamber 1d, at least one turbine 1e (e.g. a high-pressure turbine and a low-pressure turbine), and a nozzle (not shown).

[0066] The turbine 1 also includes stator blades 1f. The stator blades 1f rectify the flow at the outlet of the upstream rotor to provide maximum thrust at the outlet of the turbine 1. Figure 1 In the particular example shown, the stator blades 1f are located downstream of the fan 1a and rectify the secondary flow F2.

[0067] The fan 1a enables suction of an air flow divided into a main flow F1 and a secondary flow F2. The main flow F1 passes through a main channel of the turbine 1, while the secondary flow F2 is directed towards a secondary channel surrounding the main channel.

[0068] The main flow F1 is compressed in the low-pressure compressor 1b and then in the high-pressure compressor 1c. The compressed air is then mixed with fuel and burned in the combustion chamber 1d. The gases formed by the combustion pass through the high-pressure turbine and the low-pressure turbine. The gases finally escape through the nozzle, the cross section of which enables them to be accelerated to generate propulsion. The secondary flow F2 passes through the stator vanes 1f, which accelerates the circulation speed of the secondary flow F2 to generate propulsion.

[0069] The fan 1a, the low-pressure compressor 1b, the high-pressure compressor 1c, the high-pressure turbine and / or the low-pressure turbine 1e and the stator blades 1f include blades 2. The blades 2 may be rotatably movable about a longitudinal axis X (e.g. Figure 2 The blades in the figure are fixed relative to the axis X (e.g. Figure 1 The stator vane 1f in the figure is called the vane 2 of the outlet guide vane (OGV).

[0070] The object of the present invention is to produce a blade made of composite material for a turbomachine, in particular for an aircraft. Figure 1 The blade of the present invention is described in the context of a fan 1 a of a turbine 1 .

[0071] However, the present invention is not limited to fan blades of ducted turbines, and can also be applied to other types of blades made of composite materials (e.g., fixed blades or moving blades of low-pressure compressor 1b and high-pressure compressor 1c of turbine 1, and fixed blades or moving blades of high-pressure turbine and low-pressure turbine). The present invention can be applied to propellers of unducted turbines (e.g., open rotor architecture).

[0072] Reference Figure 2 Each blade 2 is along the longitudinal axis A (at Figure 2 and along the elongated axis B (in Figure 2 The axis A is substantially perpendicular to the axis B. The axis A is substantially parallel to the axis X of the turbine 1 .

[0073] The blade 2 comprises a blade 20. The blade 20 comprises a pressure side 21 and a suction side 22 joined together by a leading edge 23 and a trailing edge 24. The blade 20 may have an aerodynamic profile to form an aerodynamic portion of the blade 2. To achieve this, the blade 20 may have a curved profile of variable thickness between the leading edge 23 of the blade and the trailing edge 24 of the blade. The blade 20 may comprise a first longitudinal end connected to a root 26 of the blade 2 and a second longitudinal end opposite the first longitudinal end. The second longitudinal end is free and is configured to form a blade tip 25 (or head).

[0074] The blade 2 may also include a reinforcement or shroud 3 in the form of a metal foil for protecting the leading edge 23. In this example, the shroud 3 extends from the leading edge 23 of the blade 20 over a portion of the length of the pressure side surface 21 and the suction side surface 22 (relative to the axis B) and in height (relative to the axis A).

[0075] As described above in the technical background of the present invention, a blade made of composite material can be manufactured by stacking fiber layers.

[0076] Now refer to Figure 3 and Fig.11b The method for manufacturing a blade 2 according to the invention will now be described.

[0077] Figure 3 A block diagram showing an example of the method described in the present invention is shown.

[0078] Generally speaking, the method for manufacturing the blade 2 may include the following steps:

[0079] (a) stacking a plurality of fiber layers 202 in succession to form a fiber blank 200,

[0080] (b) shaping the fiber blank 200 to obtain a fiber preform 220 of the blade 20, and

[0081] (d) Densifying the fiber preform 220 with resin to form a blade 2 made of composite material.

[0082] One of the features of the present invention is that the fiber blank 200 of step (a) includes a first portion 204 and a second portion 206 that are continuously joined together. In other words, the first portion 204 and the second portion 206 are integrally formed using continuous fibers. This enhances the mechanical strength of the blade, particularly at the leading edge 23 and / or the trailing edge 24 in the event of a collision or impact from a foreign object during operation.

[0083] For example, the fiber layer 202 includes glass fibers, carbon fibers, aramid fibers, polyamide fibers, ceramic fibers, metal fibers, oxide fibers, or a mixture of at least two of these fibers.

[0084] The fiber layer 202 may be pre-impregnated with resin or in a virgin state (or dry fibers). "Virgin fibers" or "dry fibers" refers to a fiber layer 202 that includes fibers that have not been previously impregnated with resin.

[0085] The fiber layer 202 may include a binder.

[0086] exist Figure 4a In the example shown, the fiber blank 200 has a substantially flat shape. Alternatively, the fiber blank 200 may have a substantially curved shape, in particular a U-shape or a V-shape ( Figure 8 ). In particular, the curved shape of the fiber blank 200 facilitates the formation of the folding line P in step (b), which will be described below.

[0087] In particular, step (b) comprises: Figure 4b) bends the fiber blank 200. The line P may be substantially parallel to the axis A. The folding line P extends between the first portion 204 and the second portion 206 to form a pressure side skin 222 and a suction side skin 224 ( 226 ) of the fiber preform 220 on both sides of the folding line P, respectively. Figure 5 ).

[0088] like Figure 4b and Figure 5 As shown in the example in FIG. 2 , the first portion 204 and the second portion 206 are folded together to join the pressure side skin 222 and the suction side skin 224 together. The first portion 204 may be configured to form the pressure side skin 222 and the second portion 206 may be configured to form the suction side skin 224 of the fiber preform 220 .

[0089] Reference Figure 5 The fiber preform 220 of step (b) thus comprises a pressure side skin 222 configured to form the pressure side 21 and a suction side skin 224 configured to form the suction side 22 of the blade 20. The pressure side skin 222 and the suction side skin 224 are joined together in particular along the folding line P.

[0090] The leading edge 23 or the trailing edge 24 is located at and along the fold line P.

[0091] The pressure side skin 222 may include a first edge 226 opposite to the fold line P (particularly radially opposite to the line P). The suction side skin 224 may include a second edge 228 opposite to the fold line P.

[0092] exist Figure 5 In the example shown, the first edge 226 and the second edge 228 are brought together to form a leading edge 23 located on the fold line P.

[0093] Advantageously, step (a) of the method can be implemented manually or by a machine 4. The machine 4 can be automated or mechanized. For example, step (a) can be implemented by an automated machine 4 using AFP, ATL or P&P technology.

[0094] Step (b) of shaping the fiber blank 200 may be performed at a predetermined forming temperature. For example, in the case where the fiber layer 202 is pre-impregnated with a thermosetting resin, the forming temperature may be low, between 30° C. and 100° C. The forming temperature may vary depending on the polymer resin used. A heating system (e.g., an oven) may be used in step (b) to shape the fiber blank by heating.

[0095] The folding in step (b) can be performed by compacting at a predetermined pressure and / or a predetermined vacuum. For example, in the case of a fiber layer 202 pre-impregnated with resin, the fiber blank 200 is compacted at a vacuum between -300 mbar and -900 mbar.

[0096] The pressing pressure or vacuum may vary depending on the resin material.

[0097] In addition or alternatively to the vacuum, pressure may be applied. In this case, for example in the case of a fiber layer 202 pre-impregnated with resin, the pressing pressure may be between 1 bar and 10 bar.

[0098] Step (b) may be performed in an oven, an autoclave, a press, or any other tool suitable for folding the fiber blank 200 .

[0099] At the end of step (b) of the method, the pressure side skin 222 and the suction side skin 224 of the formed fiber preform 220 are formed by forming the leading edge 23 (at Figure 5 In the example of ), the first edge 226 and the second edge 228 of the trailing edge 24 are joined together.

[0100] Figure 6 , Figure 8 and Fig.10 A first form, a second form and a third embodiment of the blade 2 are shown respectively.

[0101] exist Figure 6 In the first embodiment of the method shown, step (a) is implemented by a machine 4, in particular a machine of the AFP type. To achieve this, the machine 4 comprises a head 40, known as a laying head or stacking head, and a first support 42, known as a stacking support. The head 40 is used to successively deposit a plurality of fiber layers, one on top of the other, in particular on a first surface 44 of the first support 42. Figure 6 In the example shown, the first surface 44 is flat. The fiber blank 200 obtained at the end of step (a) therefore has a flat shape.

[0102] Alternatively, the first surface 44 of the first support member 42 is curved, in particular in a U-shape or a V-shape ( Figure 8 ) to define a U-shape or V-shape with a bend ( Figure 8 ) of the fiber blank 200.

[0103] Advantageously, the first surface 44 may include a first protruding portion 46. The first protruding portion 46 defines a fold line P. In this manner, the first protruding portion 46 may be configured to form the leading edge 23 and / or the trailing edge 21 of the blade 20. The first protruding portion 46 may be generally U-shaped ( Figure 7a) or V-shaped ( Figure 7b ).

[0104] In step (b), the fiber blank 200 can be mounted on the second surface 50 of the second support 5, referred to as the forming support. Figure 6 In the example shown, the second surface 50 is flat. Alternatively, the second surface 50 of the second support 5 is in particular in a U-shape or a V-shape ( Figure 8 )bending.

[0105] Advantageously, the second surface 50 may include a second protruding portion 52. The second protruding portion 52 defines a fold line P. In this manner, the second protruding portion 52 may be configured to form the leading edge 23 and / or the trailing edge 21 of the blade 20. The second protruding portion 52 may be generally U-shaped ( Figure 7a ) or V-shaped ( Figure 7b ).

[0106] The same support 42, 5 can be used to carry out steps (a) and (b), or conversely, two different supports 42, 5 can be used to carry out steps (a) and (b) of the method of the invention.

[0107] exist Figure 6 In the example shown, at the end of step (b), the fiber preform 220 includes a pressure side skin 222 and a suction side skin 224 that are joined together.

[0108] Figure 8 The second embodiment shown is Figure 6 The method of the first embodiment shown differs in that a first support 42 and a second support 5 are used.

[0109] In the second embodiment, the first surface 44 and the second surface 50 of the support 42, 5 have a substantially V-shaped curved shape. Therefore, the fiber blank 200 obtained in step (a) has a V-shaped bend.

[0110] The machine 4 may further include a holding member 48 (eg, a cylindrical plate). In particular, the holding member 48 supports the V-shaped curvature of the first surface 44 of the first support 42 .

[0111] As reference Figure 7a and Figure 7b As described, the first surface 44 of the first support member 42 of the second embodiment may include a first protruding portion 46 ( Figure 9a and Figure 9b ). Similarly, the second surface 50 of the second support member 5 of the second embodiment may include a second protruding portion 52 ( Figure 9b and Figure 9bThe first protruding portion 46 and the second protruding portion 52 define the folding line P, and also specifically define the leading edge 23 or the trailing edge 21 of the blade 20. The first protruding portion 46 and the second protruding portion 52 of the second embodiment may each be substantially U-shaped ( Figure 9a ) or V-shaped ( Figure 9b ).

[0112] Alternatively (not shown in the figure), the first surface 44 of the first support member 42 and the second surface 50 of the second support member 5 are each U-shaped curved to define a fiber blank 200 having a U-shaped curved shape. These first U-shaped curved surfaces 44 and second U-shaped curved surfaces 50 may include first protruding portions 46 and second protruding portions 52, as described with reference to the first and second embodiments of the present invention.

[0113] The method of the present invention may include a step (i) of preforming at least a portion of the fiber blank 200 formed on the first protruding portion 46 or the second protruding portion 52 (for example, in a U-shape or a V-shape) protruding from the support 42, 5. This step (i) may be implemented during step (a) or after step (a). This enables the connection area (at the folding line P) to be preformed directly on the fiber blank 200 before the step (b) of folding the fiber blank 200 to form the folded pressure side skin 222 and the suction side skin 224. In this way, at the folding line P, the dimensions (shape, size, thickness, etc.) of the area where the pressure side skin 222 and the suction side skin 224 are joined are better controlled.

[0114] For example, Fig.10 A preforming step (i) is shown after the step (a) of stacking the fiber layers 202 and before folding the fiber blank 200 in step (b). The fiber blank 200 thus comprises an intermediate portion 205 between the first portion 204 and the second portion 206. This intermediate portion 205 is located at the folding line P and is configured to form the leading edge 23 or the trailing edge 24 of the blade 20. The U-shaped or V-shaped shape of the protruding portions 46, 52 of the supports 42, 5 enables the intermediate portion 205 to be compacted to form a so-called intermediate fiber preform 225. The first portion 204 and the second portion 206 of the fiber blank 200 extend on both sides of this intermediate preform 225. Then, in step (b), the first portion 204 and the second portion 206 are folded together to form the fiber preform 220.

[0115] The densification step (d) of the method may comprise polymerizing the resin (or, in other words, curing the resin into a polymer matrix) by heat treatment. To this end, during the manufacture of the fiber blanks 200, 201, 203, in particular in step (a) and / or step (i), the fiber preform 220 may be previously impregnated with resin. For example, the head 40 of the machine 4 deposits rovings in the form of a mixture of fibers and resin in layers superimposed on each other to form a pre-impregnated fiber blank. In this case, step (d) may be implemented in an autoclave using a resin injection molding technique similar to Same Qualified Resin Transfer Molding (SQRTM) or any other technique for polymerizing the fiber preform in a controlled geometry.

[0116] Alternatively, the densification step (d) of the method may include injecting resin into the fiber preform 220 and polymerizing the resin by heat treatment. To achieve this, the fiber preform 220 includes a dry fiber layer 202. For example, a blade made of composite material can be manufactured using a resin transfer molding (RTM) liquid resin injection molding technology. To this end, the fiber preform 220 obtained in step (b) can be arranged in a mold to be densified by a polymer matrix, which includes impregnating the fiber preform 220 with an injection resin and polymerizing the injection resin to obtain the final blade. The resin can be injected into the fiber preform 220 before step (d) or in step (d).

[0117] The resin may be a thermosetting resin, such as an epoxy resin.

[0118] The resin may be a thermoplastic, such as polyetheretherketone, polyaryletherketone or polyetherimide.

[0119] The method of the invention may also comprise a step (c) of adding at least one reinforcing insert 232 to the interior space 230 delimited by the pressure side skin 222 and the suction side skin 224 of the fiber preform 220. This insert is used in particular to hold the pressure side skin and the suction side skin in place during the densification step (d) of the fiber preform.

[0120] The reinforcing insert 232 may be accommodated in the entire surface of the inner space 230 ( Fig.11a Alternatively, the reinforcing inserts 232 may be arranged at several predetermined points in the interior space 232 ( Fig.11b ).

[0121] Reference Fig.11bA plurality of reinforcement inserts 232 in the form of stiffeners extend radially (relative to line P or axis A) between the pressure side skin 222 and the suction side skin 224 .

[0122] The reinforcing insert 232 may be made of foam, porous material or composite material. For example, the porous material is selected from polymer foam (e.g. type polymethacrylic imide), aluminum foam, metal tin phosphor bronze and / or aromatic polyamide polymers (e.g. type of aromatic polyamide polymer).

[0123] The reinforcing insert 230 may comprise a sealing enclosure encapsulating the porous material. This in particular protects the porous material during step (d). The sealing enclosure may be made of a composite material.

[0124] The reinforcement insert 230 may be manufactured by additive manufacturing.

[0125] The reinforcement insert 230 may be made from a thermoplastic structure that may be injected between the pressure side skin 222 and the suction side skin 224 .

Claims

1. A method for manufacturing a blade (2) made of composite material for an aircraft turbine (1), the blade (2) comprising a blade (20) having a pressure side (21) and a suction side (22) interconnected by a leading edge (23) and a trailing edge (24), the method comprising the following steps: (a) stacking a plurality of fiber layers (202) in succession to form a fiber blank (200), (b) shaping the fiber blank (200) to obtain a fiber preform (220) of the blade (20), the fiber preform (220) comprising a pressure side skin (222) and a suction side skin (224) joined together, the pressure side skin and the suction side skin being configured to respectively form the pressure side (21) and the suction side (22) of the blade (20), and (d) densifying the fiber preform (220) with a resin to form the blade (2) made of composite material, The fiber blank (200) comprises a first portion (204) and a second portion (206) which are continuously joined together in step (a). Step (b) comprises folding the fiber blank (200) along a line (P) extending between the first portion (204) and the second portion (206) to form the pressure side skin (222) and the suction side skin (224) on both sides of the fold line (P), and the leading edge (23) of the blade or alternatively the trailing edge (24) of the blade is positioned at and along the fold line (P), and the edges (226, 228) of the pressure side skin (222) and the suction side skin (224) opposite to the fold line (P) are joined together to form the leading edge (23) of the blade (20) or alternatively the trailing edge (24) of the blade; The fiber blank (200) and / or the fiber preform (220) is formed on a flat, U-shaped curved or V-shaped curved surface (44, 50) of a support (42, 5), the surface (44, 50) of the support (42, 5) further comprising a U-shaped protrusion or a V-shaped protrusion (46, 52), the U-shaped protrusion or the V-shaped protrusion being configured to define the folding line (P); And the method comprises in step (a) a step (i) of preforming at least a portion of the fiber blank (200) formed on the U-shaped protrusion or the V-shaped protrusion (46, 52) of the support member (42, 5).

2. The manufacturing method according to claim 1, characterized in that: In step (a) or step (b), the fiber blank (200) has a substantially flat and / or U-shaped or V-shaped curved portion.

3. The manufacturing method according to claim 1 or 2, characterized in that: Step (a) is performed manually or by a machine (4).

4. The manufacturing method according to any one of claims 1 to 3, characterized in that: Step (d) includes impregnating the fiber preform (220) with the resin and polymerizing the resin by heat treatment.

5. The manufacturing method according to claim 4, characterized in that: Prior to step (d), the resin is injected into the fiber preform (220), or the fiber blank (200) is pre-impregnated with the resin.

6. The manufacturing method according to claim 4 or claim 5, characterized in that: The resin is thermosetting, and is, for example, epoxy resin.

7. The manufacturing method according to claim 4 or claim 5, characterized in that: The resin is thermoplastic, and is, for example, polyetheretherketone resin, polyaryletherketone or polyetherimide.

8. The manufacturing method according to any one of claims 1 to 7, characterized in that: The method comprises a step (c) of adding at least one reinforcement insert (232) into an interior space (230) defined by a pressure side skin (222) and a suction side skin (224) of the fiber preform (220), for example the reinforcement insert (232) being made of foam, porous material or composite material.

9. The manufacturing method according to claim 8, characterized in that: The reinforcement insert (232) is made of a porous material, and the reinforcement insert (232) includes a sealed enclosure encapsulating the porous material.

10. The manufacturing method according to claim 8 or claim 9, characterized in that: The reinforcement insert (232) is manufactured by additive manufacturing.

11. The manufacturing method according to any one of the preceding claims, characterized in that The fiber layers (202) each include glass fibers, carbon fibers, aramid fibers, polyamide fibers, ceramic fibers, metal fibers, oxide fibers, or a mixture of at least two of these fibers.

12. The manufacturing method according to any one of the preceding claims, characterized in that In step (b), folding the fiber blank (200) is performed by compacting at a pressure between 300 Pascal and 800 Pascal.

13. The manufacturing method according to any one of claims 1 to 11, characterized in that: In step (b), folding the fiber blank (200) is performed by compacting under a vacuum between -300 mbar and -900 mbar.

14. The manufacturing method according to any one of the preceding claims, characterized in that In case the fiber layer (202) is pre-impregnated with a thermosetting resin, step (b) is performed at a predetermined temperature between 30°C and 100°C.

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