METHOD FOR MANUFACTURING A TURBOMACHINE PART COMPRISING A HONEYCOMB STRUCTURE

Abstract

The invention relates to a method for manufacturing a turbomachine part, comprising a wall and a honeycomb structure made of composite material on at least a portion of one face of the wall, the honeycomb structure having at least one first grid of cells and at least one first skin covering this first grid of cells, the method comprising the following steps of: (a) supplying the wall, and (b) creating the honeycomb structure on the face, wherein step (b) of creating the honeycomb structure comprises the following substeps of: (b1) laying first plies of composite material by draping to form the first skin, and (b2) forming the first grid of cells by additive manufacturing, substep (b1) being carried out before or after substep (b2). Figure for the abstract: Figure 10

Description

Title of the invention: METHOD FOR MANUFACTURING A TURBOMACHINE PART COMPRISING A HONEYCOMB STRUCTURE technical field

[0001] The invention relates to the field of manufacturing turbomachine parts, particularly for aircraft. More specifically, the present invention relates to a method for manufacturing a turbomachine part comprising a wall and a honeycomb structure made of composite material on at least a portion of one face of this wall. Technical background

[0002] A turbomachine, particularly for aircraft, comprises parts having a wall and a honeycomb structure made of composite material on at least a portion of one face of that wall. The honeycomb structure comprises one or more cell arrays and one or more skins covering the cell array(s). The honeycomb structure notably provides mechanical, vibrational, and acoustic properties.

[0003] Some turbomachine parts may include stiffeners. One of the drawbacks of manufacturing stiffeners is that they can be delicate and time-consuming to assemble onto the turbomachine part (such as an acoustic panel or a self-stiffening panel). One solution is to manufacture these stiffeners in the form of a honeycomb structure in order to lighten the part.

[0004] Such parts may be hollow or have a hollow portion containing the honeycomb structure. By way of example, turbomachine parts comprising (or capable of comprising) the honeycomb structure may be a gas flow discharge duct, an annular casing, an acoustic panel, etc.

[0005] Such parts can be made of metallic or composite material.

[0006] It is known to manufacture such turbomachine parts from composite material using the resin transfer molding (RTM) technique. Generally, hollow turbomachine parts are preferentially manufactured by RTM. This technique requires the use of resin injection molds, liners to encase the fibrous preform intended to form the turbomachine part, an autoclave to perform resin polymerization, and cores to create a hollow portion of the turbomachine part and / or the honeycomb structure. This technique can be tedious and complex to perform since it requires the use of several tools.

[0007] Regarding the realization of the honeycomb structure of the turbomachine part, it The honeycomb structure is generally formed by manufacturing the honeycomb grid and the skin(s) separately, then assembling them with adhesives, and finally consolidating the assembly (for example, by welding, bonding, and the use of other assembly and consolidation tools). When the honeycomb structure is produced on the face of a curved wall, the honeycomb grid is generally bent and then assembled onto this curved wall. One of the drawbacks of this method of manufacturing the honeycomb structure is that it is not suitable for turbomachine parts, for example, those with small dimensions (such as those with a small radius of curvature), cylindrical shapes, or, in general, those with a non-developable surface (such as spherical, elliptical, or hollow shapes).

[0008] A "non-developable surface" is understood to be a surface exhibiting a complex curvature, in particular a curvature in at least two different directions. Such a non-developable surface is, for example, present in duct-type turbomachine parts, an outer casing or panel called a fixed internal structure (IFS), a conical nacelle, etc.

[0009] Fig. 1 illustrates an example of a cylindrical part 1 comprising a first network of cells RI extending around a cylindrical wall 12 of this part 1, and a second network of cells R2 extending over a circular wall 14 connected to the cylindrical wall 12. Dashed arrows represent connection defects Dr at the level between the first RI and second R2 networks of cells at the level of a cylindrical perimeter 16 of the part 1.

[0010] Fig. 2 illustrates an example of maximum curvature Cmax achievable on a network of cells R.

[0011] Figure 3 illustrates an example of deformation Df on a curved alveolar network R. In particular, the walls Rp of the alveolar cells Rc forming the alveolar network R are crushed against each other.

[0012] In this context, it is interesting to propose a solution that makes it possible to overcome at least one of the aforementioned disadvantages, in particular by optimizing and simplifying the realization of a honeycomb structure on at least part of a turbomachine part. Summary of the invention

[0013] The present invention proposes a simple, effective and economical solution to the aforementioned disadvantages of the prior art.

[0014] To this end, the invention relates to a method for manufacturing a turbomachine part, in particular for an aircraft, the turbomachine part comprising a wall and a honeycomb structure made of composite material on at least a portion of one face of the wall, the honeycomb structure comprising at least a first network of cells and at less a first skin covering this first network of cells, the process comprising the following steps of: (a) supplying the wall, and (b) fabrication of the honeycomb structure on at least a portion of the wall face.

[0015] According to the invention, step (b) of fabrication of the honeycomb structure comprises the following substeps of: (bi) laying of first layers of composite material by draping to form said at least one first skin, and (b2) formation of said at least a first network of cells by additive manufacturing,

[0016] substep (bi) being carried out before or after substep (b2).

[0017] Thus, this solution makes it possible to achieve the aforementioned objective. In general, the process according to the invention makes it possible to optimize the creation of a honeycomb structure on at least a portion of a face of a wall of the tur-bomachine part, by combining the techniques of depositing layers of composite material by draping and additive manufacturing.

[0018] In particular, composite material plies and additive manufacturing allow for the simple and efficient formation of, respectively, the skin(s) and the cell network(s) composing the honeycomb structure, notably without any dimensional constraints on the turbomachine part. Indeed, additive manufacturing makes it possible to print the cell network(s) directly onto any possible dimensions of the skin and / or the wall face of the turbomachine part. These dimensions can include a small radius of curvature, a cylindrical shape, and / or a non-developable surface.

[0019] The combination of draping and additive manufacturing techniques also makes it possible to functionalize the honeycomb structure, notably by imparting mechanical properties such as stiffness in addition to vibration and acoustic properties, thereby enhancing the rigidity and flexural strength of the part. Indeed, the invention makes it possible to produce both a simple honeycomb structure (composed, for example, of a single skin and a network of cells) or a sandwich-type structure (composed, for example, of a double skin with one or more networks of cells) on turbomachine parts of simple or complex shapes (i.e., a wall with, for example, an unconventional curvature with a small radius of curvature, a double curvature, etc.). In this way, the honeycomb structure produced by the process of the invention makes it possible to increase the local stiffness (particularly at the wall level) of the turbomachine part.The vibrational properties of the honeycomb structure obtained by the process of the invention enhance the absorption of the various resonance frequencies of the operating turbomachine, preventing the turbomachine component from resonating. The acoustic properties of the structure... The alveolar structure obtained by the process of the invention makes it possible to reduce noise pollution (particularly when the alveolar structure has at least two skins) since the network of alveoli can adapt to the specific dimensions of the room.

[0020] The invention therefore has the advantage of being based on a simple design, offering very high reliability, and minimal impact in terms of cost, mass, and size. Furthermore, the invention reduces the environmental impact by improving and simplifying the manufacturing of the turbomachine component.

[0021] The term "composite material plies" refers to one or more fibrous layers (or, in other words, fabrics), each of which can be produced, for example, by two- or three-dimensional weaving. The composite material may comprise a fibrous preform embedded in a resin. The composite material may have a ceramic matrix (CMC) or an organic matrix (CMO).

[0022] The term “draping” means the successive deposition by superposition and stacking of several layers of composite material to form, in the present application, the skin or skins of the alveolar structure.

[0023] Additive manufacturing means the production by adding material of an element or a portion of an element (such as a filament, granules, a resin, etc.) from a digital object which in the present application may be the network of cells.

[0024] The manufacturing process according to the invention may include one or more of the following features, taken individually or in combination with each other:

[0025] - the alveolar structure comprises at least one second skin, said at least one first network of cells extending between said at least one first skin and said at least one second skin, wherein the process includes a substep (b3) of depositing second plies of composite material by draping to form said at least one second skin, this substep (b3) being carried out before substep (b2) and substep (bi) being carried out after substep (b2);

[0026] - the alveolar structure comprises at least a second network of alveoli, said alveoli less a first skin covering said first cell network and said at least a second skin being perforated and interposed between said first and second cell networks, wherein the process includes a substep (b4) of forming said at least a second cell network by additive manufacturing, this substep (b4) being carried out before substep (b3);

[0027] - the turbomachine part comprises at least a flat portion, a portion annular, a curved portion and / or a perforated portion, in which at least one of the flat, annular, curved and perforated portions includes at least one portion of the face on which the alveolar structure is made;

[0028] - the draping of the sub-steps (bj and (b3) are carried out manually or in such a way as to automatic, and additive manufacturing of substeps (b2) and (b4) are carried out by laser powder bed fusion (LBM) or by extrusion (EAM);

[0029] - at least one of said first and second networks of cells has a thickness between 0.2 and 55 mm;

[0030] - at least one of said first and second skins has a thickness of between 0.4 and 7 mm;

[0031] - said first network of cells and / or said second network of cells comprises polygonal cells, for example triangular, quadrangular, pentagonal or hexagonal and / or rounded in shape, formed by additive manufacturing;

[0032] - the turbomachine part is selected from a discharge duct of a gas flow, an annular casing and an acoustic panel;

[0033] - the turbomachine part is made of metallic or composite material;

[0034] — the first plies in composite material and / or the second plies in material composites each have a maximum ply width of approximately 20 mm or up to approximately 40 mm; this allows for AFP type draping;

[0035] — the first plies in composite material and / or the second plies in material composites each have a pleat width between 0.7 and 6.5 mm; this allows for micro-AFP type draping.

[0036] The invention may also relate to a turbomachine component comprising a wall and a honeycomb structure made of composite material on at least a portion of one face of the wall, the honeycomb structure having at least one first grid of cells and at least one first skin covering this first grid of cells. This turbomachine component can be obtained by the manufacturing process according to one of the features of the invention.

[0037] The turbomachine part can be chosen in a non-limiting way from a gas flow discharge duct, an annular casing, a self-stiffening panel and an acoustic panel.

[0038] The turbomachine part can be made of metallic or composite material. Brief description of the figures

[0039] The present invention will be better understood and other details, features and advantages of the present invention will become more apparent upon reading the following description of a non-limiting example, with reference to the accompanying drawings in which:

[0040] [Fig.1] is a perspective view schematically representing a cylindrical part comprising an alveolar structure with networks of alveoli according to the prior art;

[0041] [Fig.2] is a partial perspective view representing a curved alveolar network of another alveolar structure according to the prior art;

[0042] [Fig.3] is an axial and partial cross-sectional view representing a deformed alveolar network of another alveolar structure according to the prior art;

[0043] [Fig.4a] is a perspective view of a gas flow discharge conduit comprising an alveolar structure according to the invention;

[0044] [Fig.4b] is a perspective and enlarged view of the alveolar structure of [Fig.4a];

[0045] [Fig.5] is a schematic perspective view representing an annular housing comprising a honeycomb structure according to the invention;

[0046] [Fig.6] is a schematic view of a turbomachine part with a flat surface comprising a honeycomb structure according to the invention;

[0047] [Fig.7] is a schematic cross-section and partial view of a first example of the alveolar structure according to the invention;

[0048] [Fig.8] is a schematic cross-section and partial view of a second example of the alveolar structure according to the invention;

[0049] [Fig.9] is a schematic cross-section and partial view of a third example of the alveolar structure according to the invention;

[0050] [Fig. 10] is a diagram of a first example of a manufacturing process for a turbomachine part comprising the honeycomb structure of [Fig. 7];

[0051] [Fig. 11] is a block diagram of a second example of a method for manufacturing a turbomachine part comprising the honeycomb structure of [Fig. 8];

[0052] [Fig. 12] is a block diagram of a third example of a method for manufacturing a turbomachine part comprising the honeycomb structure of [Fig. 10];

[0053] [Fig.13] is an axial and enlarged cross-sectional view of a network of alveoli without deformation of the alveolar structure according to the invention;

[0054] Elements having the same functions in the different implementations have the same references in the figures. Detailed description of the invention

[0055] Figures 1, 2 and 3 have been described in the technical background of this application and illustrate examples of a turbomachine part having a prior art honeycomb structure.

[0056] The invention applies generally and without limitation to various types of turbomachine parts, particularly aircraft turbomachinery. The turbomachine may be a turboprop or a turbojet.

[0057] The turbomachine can conventionally comprise, from upstream to downstream (relative to the direction of gas flow in the turbomachine), a blower, one or more components pressors, an annular combustion chamber, one or more turbines and possibly an exhaust nozzle.

[0058] The invention finds an advantageous but not exclusive application in parts 2 which can be a discharge conduit for a gas flow (figures 4a and 4b), an annular housing ([Fig.5]), an acoustic panel or a self-stiffening panel ([Fig.6]).

[0059] Part 2 of the invention can therefore be any part of the turbomachine having a wall of complex or simple shape.

[0060] Part 2 can be made of metallic material (such as aluminium, steel or titanium) or of composite material.

[0061] Part 2 comprises a wall 3 and a honeycomb structure 4 made of composite material on at least part of a face 30 of the wall 3.

[0062] Part 2 may include at least one flat portion 2a, one annular portion 2b, one curved portion 2c and / or one perforated portion 2d. The flat portion 2a, annular portion 2b, curved portion 2c and / or perforated portion 2b may be formed on the wall 3. At least one of the flat portion 2a, annular portion 2b, curved portion 2c and perforated portion 2d may include the face 30 with the alveolar structure 4.

[0063] The curved portion 2c may comprise a single curvature or several curvatures. Each curvature may be of the monoclastic type (i.e. the surface of the curved portion has a curvature along a single plane), synclastic (i.e. the surface of the curved portion has curvatures along planes and on the same side) or anticlastic (i.e. the surface of the curved portion has curvatures along several planes and on different sides).

[0064] Figures 4a to 6 illustrate different configurations of part 2 which may include the honeycomb structure 4 produced in particular according to a manufacturing process of the invention.

[0065] Figures 4a and 4b illustrate, without limitation, the discharge conduit or any other part 2 of the turbomachine having the curved portion 2c. This curved portion 2c may include the face 30 on which the honeycomb structure 4 is formed.

[0066] Figure 5 illustrates, without limitation, the annular housing or any other part 2 of the turbomachine having the annular portion 2b. This annular portion 2a may include the face 30 on which the alveolar structure 4 is formed.

[0067] Figure 6 illustrates, in a non-limiting manner, the acoustic panel, the self- stiffened or any other turbomachine part 2 having the flat portion 2a. This flat portion 2a may include the face 30 on which the honeycomb structure 4 is formed.

[0068] Figure 6 also illustrates, in a non-limiting manner, wall 3 with the perforated portion 2d with an orifice O. This perforated portion 2d may include the face 30 on which the alveolar structure 4 is formed. More particularly, the alveolar structure 4 may extend around the orifice O.

[0069] Figures 7 to 9 illustrate in a non-limiting way the different possible configurations of the alveolar structure 4 of the invention that can be formed on the wall 3 of the part 2 described above (in particular with reference to Figures 4a to 6).

[0070] The alveolar structure 4 comprises at least a first network of alveoli 42 and at least a first skin 44 covering this first network of alveoli 42.

[0071] With reference to [Fig. 7], the alveolar structure 4 can form a so-called simple structure. This simple alveolar structure 4, according to a first example, can be composed of the simple first skin 44 covering the first alveolar network 42. In the example of [Fig. 7], the first network 42 can be located on the face 30.

[0072] With reference to [Fig. 8], the alveolar structure 4 can form a so-called sandwich structure. This sandwich structure, according to a second example, can further comprise at least one second skin 48, in which the first alveolar network 42 can extend between the first 44 and second 48 skins. In the example of [Fig. 8], the second skin 48 can be located on the face 30. This second skin 48 can thus form an upper skin of the wall 3.

[0073] With reference to [Fig. 9], the honeycomb structure 4 can form a so-called 2DOF structure (an acronym for "two degrees of freedom" to designate two degrees of freedom and acoustic attenuation at two frequencies, such as low and high frequencies). This 2DOF structure, according to a third example, can further comprise at least one second honeycomb array 46, in which the first skin 44 covers the first honeycomb array 42 and the second skin 48 is perforated and interposed between the first 42 and second 46 honeycomb arrays. In the example of [Fig. 9], the second honeycomb array 46 can be located on the face 30. The second skin 48 can have perforations 480.The honeycomb structure 4 according to the third example makes it possible to reinforce the acoustic properties of part 2, in particular by attenuating two different resonance frequencies (such as a high and low frequency range) by the superposition of the first 42 and second 46 honeycomb networks.

[0074] The first alveolar array 42 and / or the second alveolar array 46 may comprise alveolar cells that may, without limitation, be polygonal in shape. These polygonal cells may be triangular, quadrilateral, pentagonal, or hexagonal, and / or rounded. Advantageously, the alveolar cells of the first alveolar array 42 and / or the second alveolar array 46 may each have lateral walls that are rounded (or otherwise curved), for example, at least at one of their lateral wall extremities.

[0075] Advantageously, the honeycomb structure 4 may include at least one annular section 40a, 40b which may be disposed upstream and / or downstream of the skins 44, 48 and the honeycomb networks 42, 46. Figure 5 illustrates, without limitation, two sections 40a, 40b may have a chamfer and may be monolithic (or otherwise solid). Alternatively, this or these annular sections 40a, 40b may be acoustically treated by including, for example, a third network of cells having smaller dimensions than the first and / or second networks of cells.

[0076] The first cell network 42 may have a first thickness E42 of between 0.2 and 55 mm. Preferably, the first thickness E42 may be between 5 and 35 mm.

[0077] The second cell array 46 may have a second thickness E46 of between 0.2 and 55 mm. Preferably, the second thickness E46 may be between 5 and 35 mm. The second thickness E46 may be the same as or different from the first thickness E42.

[0078] The first skin 44 may have a third thickness E^ of between 0.4 and 7 mm. Preferably, the third thickness E44 may be between 0.4 and 2.5 mm.

[0079] The second skin 48 may have a fourth layer E48 of between 0.4 and 7 mm. Preferably, the fourth layer E48 may be between 0.4 and 2.5 mm. The fourth layer E48 may be the same as or different from the third layer E44.

[0080] The honeycomb structure 4 is made of composite material. The composite material may comprise a fibrous preform embedded in a resin. The composite material may be ceramic matrix (CMC) or organic matrix (CMO). The fibrous preform may comprise carbon fibers, glass fibers, ceramic fibers (such as silicon carbide, glass, or aramid), polyamide fibers, metallic fibers, oxide fibers, or a mixture of at least two of these fibers. The fibers of the composite material of the honeycomb structure 4 (in particular of the first 46 and / or second 46 honeycomb arrays) may be short or long fibers.

[0081] In particular, the first skin 44 can be formed of first plies of composite material. The second skin 48 can be formed of second plies of composite material. The first and second plies of composite material can each comprise glass fibers, carbon fibers, aramid fibers, ceramic fibers (such as silicon carbide, glass, or aramid), or oxide fibers.

[0082] The resin (which can form the CMC or CMO matrix) of the composite material can be a thermoplastic or thermosetting resin, for example based on epoxy, polyepoxide, polyimide, polybismaleimide, polyurethane, polyester, polyetherimide (PEI), Polyaryletherketone family (PAEK, such as polyetheretherketone PEEK, polyetherketone PEK, polyetherketone PEKK, ...), or vinyl ester.

[0083] The present application will now describe a method for manufacturing part 2 described above (in particular with reference to Figures 4a to 6) comprising the alveolar structure 4 described below (in particular with reference to Figures 7 to 9). Figures 10 to 12 illustrate, in a non-limiting manner, various embodiments of the process of the invention.

[0084] Fig. 10 illustrates the steps of a manufacturing process for a part 2 of a tur-bomachine, in particular an aircraft.

[0085] The process comprises the following steps: (a) supply of wall 3, and (b) realization of the alveolar structure 4 on at least a portion of the face 30 of the wall 3.

[0086] One of the distinctive features of the invention is that step (b) of realizing the alveolar structure 4 comprises the following substeps: (bi) laying of composite material plies by draping to form the first skin 44, and (b2) formation of the first network of cells 42 by additive manufacturing.

[0087] Substep (bi) is to be carried out before or after substep (b2). This is represented by a double arrow on [Fig. 10].

[0088] As mentioned above, the combination of draping and additive manufacturing techniques makes it possible to form the honeycomb structure 4 directly on the portion of the face 30 of the wall 3 regardless of the shape (such as a simple or multi-curved shape, flat shape, perforated shape etc.) and size (such as the radius of curvature, the length, etc.) of this portion of the face 30. This makes it possible to strengthen the vibrational and acoustic properties of the honeycomb structure 4, and also to confer mechanical properties by locally increasing stiffness. It is not necessary to have the same reinforcements or stiffeners in the form of a honeycomb structure 4 everywhere on part 2. Indeed, with reference to [Fig.4a] or 4b, the honeycomb structure 4 can be formed specifically on the curved portion 2c of part 2 requiring local reinforcement of the mechanical, vibratory and / or acoustic properties of this part 2.

[0089] The manufacturing process for part 2 may include a substep (b3) of laying second layers of composite material by draping to form the second skin 48 of the honeycomb structure 48, as illustrated in Figures 11 and 12. This substep (b3) may be carried out before substep (b2).

[0090] The manufacturing process for part 2 may include a substep (b4) of additive manufacturing the formation of the second honeycomb network 46 of the honeycomb structure 48, as illustrated in [Fig. 12]. This substep (b4) may be carried out before substep (b3).

[0091] The alveolar structure 4 may include at least one of the planar portions 2a, annular 2b, curved 2c and perforated 2c. At least one of these flat portions 2a, annular 2b, curved 2c and perforated 2c may comprise (or form) at least one portion of the face 30 on which the alveolar structure 4 is made according to the process of the invention (in particular by substeps (b1) and (b2), and / or substep (b3) and possibly substep (b4)).

[0092] In substep (bi) and / or substep (b3), the draping of the first and / or second layers of composite material can be carried out manually or automatically. For example, substep (bi) and / or substep (b3) can be carried out using the AFP (Automated Fiber Laying) technique, the ATL (Automated Tape Laying) technique, or the P&P (Pick & Place) technique. AFP draping allows the first and / or second layers of composite material to be laid down, preferably in parallel and simultaneously, to form the first skin 44 and optionally the second skin 48. The first and / or second layers of deposited composite material can each have a ply width ranging from a few millimeters to a few tens of millimeters.For example, this pleat width per AFP draping can be a maximum of approximately 20 mm or up to approximately 40 mm.

[0093] Advantageously, the draping of the first and / or second layers of composite material can be carried out by the micro-AFP technique designating the deposition of the first and / or second layers of composite material each having a layer width of between 0.7 and 6.5 mm.

[0094] The first and / or second layers of composite material can be pre-consolidated (or in other words densified) before being draped onto the part 2, or consolidated in suitable tooling to form the final shape of, respectively, the first skin 44 and the second skin 48. The suitable tooling can be an oven, an autoclave, a vacuum bag and / or a compression press.

[0095] In substep (b2) and / or substep (b4), additive manufacturing can be carried out by laser beam melting (LBM), or by extrusion (EAM).

[0096] Powder bed fusion additive manufacturing makes it possible to produce complex-shaped parts, such as the first 42 and second 46 cell arrays of the honeycomb structure 4, regardless of the shape and dimensions of the portion of the face 30 of the part 2. Furthermore, additive manufacturing makes it easier to form and control the various possible shapes of the cell array 42, 46 (particularly of these polygonal cells). Thus, polygonal cells (for example, triangular, quadrilateral, pentagonal, or hexagonal and / or rounded) can be formed by additive manufacturing.

[0097] LBM additive manufacturing allows for the selective consolidation of powder layers in order to constitute, layer by layer, the first 42 and second 46 networks of three-dimensional cells.

[0098] EAM additive manufacturing allows a continuous filament of composite or thermoplastic material to be deposited to build layer by layer the first 42 and second 46 networks of three-dimensional cells.

[0099] The first example of the alveolar structure 4 of [Fig.7] can be formed by carrying out substep (b2) to form the first alveolar network 42 in particular on face 30, then substep (bi) to form the first skin 44 covering the first alveolar network 42 obtained in substep (b2).

[0100] The second example of the alveolar structure 4 of [Fig.8] can be formed by carrying out the following steps in the following order: - substep (b3) to form the second skin 48, particularly on face 30, - then substep (b2) to form the first network of alveoli 42, particularly on the second skin 48 obtained in substep (b3), and - finally the substep (bi) to form the first skin 42 covering the first network of alveoli 42 obtained in the substep (b2).

[0101] These steps for realizing the alveolar structure 4 according to the second example are shown in [Fig.11].

[0102] The third example of the alveolar structure 4 of [Fig.9] can be formed by carrying out the following steps in the following order: - substep (b4) to form the second network of alveoli 46, particularly on face 30, - then substep (b3) to form the second skin 48 covering in particular the second network of alveoli 46 obtained in substep (b4), - then substep (b2) to form the first network of alveoli 42, particularly on the second skin 48 obtained in substep (b3), and - finally the sub-step (b J to form the first skin 44 covering the first network of alveoli 42 obtained in the sub-step (b2).

[0103] These steps for realizing the alveolar structure 4 according to the second example are shown in [Fig.12].

[0104] The second skin 48 can be perforated with perforations 480 before or after the draping of substep (b3).

[0105] With reference to [Fig. 13], the formation of the first cell network 42 and / or the second cell network 46 by additive manufacturing, particularly on the annular portion 2b or curved portion 2b, makes it possible to form the lateral walls of the polygonal cells without deformation. In other words, the lateral walls of the cells al Veolar cells of alveolar networks 42, 46 exhibit constant thicknesses regardless of the curvature of wall 3. Indeed, these lateral walls of alveolar cells (especially polygonal in shape) which are curved, can be distant from each other via a gap J.

[0106] The present application will now describe in a non-limiting manner two examples of tests for measuring and comparing the mechanical properties (namely the bending force) of part 2 produced according to the process of the invention.

[0107] According to a first test, the bending force at break (measured in Newtons N) is measured on three different test specimens EAi, EA2, EA3. A first test specimen EAi comprises only the first 44 or the second 48 skin formed by draping the first or second plies of composite material. More specifically, the thickness of the first specimen EAi is approximately 1 mm, representing, for example, eight plies of composite material deposited by draping. This first specimen EAi exhibits a bending force of approximately 45 N.

[0108] A second test specimen EA2 comprises the first 44 or second 48 skin with a thickness of approximately 1 mm and the first 42 or second 46 network of cells formed by additive manufacturing FFF (English acronym for "Fused Filament Fabrication" to designate a molten filament deposition) with a PEI thermoplastic resin of the Ultem® 1010 type. This second specimen EA2 exhibits a higher bending force of approximately 65 N.

[0109] A third test specimen EA3 comprises the first 44 or second 48 skin of approximately 1 mm thickness and the first 42 or second 46 network of cells formed by additive manufacturing FFF with a thermoplastic resin PEI of the Ultem® 9085 type. This third specimen EA3 exhibits an even greater bending force of approximately 140 N.

[0110] Thus, the results of the first test lead to the conclusion that part 2, incorporating the first 42 or second 46 network of cells produced by additive manufacturing, significantly increases the bending strength. The choice of composite material also makes it possible to increase the bending strength of part 2.

[0111] According to a second test, the stiffness of three different test specimens EA4, EA5, EA6 is measured.

[0112] A fourth test specimen EA4 is made of aluminum. This fourth specimen EA4, referred to as the reference specimen, exhibits a bending force of one for a given weight.

[0113] A fifth test specimen EA5 comprises a first layer Ci made by AFP draping of PEEK material and approximately 6.35 mm thick, and a second layer C2 partially enveloping the first layer Ci and made of PEI material. This fifth specimen EA5 exhibits a bending strength twice as high. load-bearing with a weight reduced by half compared to the fourth EA4 test specimen.

[0114] A sixth test specimen EA6 comprises the first layer Ci and the second layer C2 of the fifth test specimen EA5, and a third layer C3 extending radially from the first layer Ci, having a thickness of approximately 1 mm and produced by additive manufacturing. This sixth specimen EA6 exhibits a bending strength that is more than 2.5 times greater for a weight reduced by approximately 0.6 compared to the fourth specimen EA4.

[0115] The fifth EA5 and sixth EA6 test specimens exhibit a greater bending force for a reduced weight than those of the fourth test specimen EA4.

[0116] Thus, the results of the second test allow us to conclude that the sixth test specimen EA6 (corresponding sensitive to the part 2 formed according to the process of the invention) presents a significant gain in rigidity.

Claims

Demands

1. A method for manufacturing a turbomachine part (2), particularly an aircraft turbomachine part, the turbomachine part (2) comprising a wall (3) and a honeycomb structure (4) made of composite material on at least a portion of a face (30) of the wall (3), the honeycomb structure (4) having at least one first grid of cells (42) and at least one first skin (44) covering this first grid of cells (42), the method comprising the following steps of: (a) supplying the wall (3), and (b) forming the honeycomb structure (4) on at least a portion of the face (30) of the wall (3), characterized in that step (b) of forming the honeycomb structure (4) comprises the following substeps of: (b1) laying first plies of composite material by draping to form said at least one first skin (44), and (b2) forming said at least one first grid of cells (42) by additive manufacturing,substep (bj) being performed before or after substep (b2).

2. A manufacturing method according to claim 1, characterized in that the honeycomb structure (4) comprises at least one second skin (48), said at least one first network of cells (42) extending between said at least one first skin (44) and said at least one second skin (48), wherein the method comprises a substep (b3) of depositing second plies of composite material by draping to form said at least one second skin (48), this substep (b3) being carried out before substep (b2) and substep (b1) being carried out after substep (b2).

3. h Manufacturing method according to claim 2, characterized in that the honeycomb structure (4) comprises at least one second honeycomb network (46), said at least one first skin (44) covering said first honeycomb network (42) and said at least one second skin (48) being perforated and intercalated between said first (42) and second (46) honeycomb networks, in which the method comprises a substep (b4) of forming said at least one second honeycomb network (46) by additive manufacturing, this substep (b4) being carried out before substep (b3).

4. A manufacturing process according to claim 3, characterized in that the draping of substeps (b1) and (b3) are carried out manually or automatically, and additive manufacturing of substeps (b2) and (b4) are carried out by laser powder bed fusion (LBM) or by extrusion (EAM).

5. Manufacturing method according to claim 3 or 4, characterized in that at least one of said first (42) and second (46) cell networks has a thickness (E42, E44) between 0.2 and 55 mm.

6. A manufacturing method according to any one of claims 2 to 5, characterized in that at least one of said first (44) and second (48) skins has a thickness (E44, E46) between 0.4 and 7 mm.

7. A manufacturing method according to any one of claims 3 to 6, characterized in that said first cell array (42) and / or said second cell array (46) comprises polygonal cells, for example of triangular, quadrangular, pentagonal or hexagonal shape and / or of rounded shape, formed by additive manufacturing.

8. A manufacturing method according to any one of the preceding claims, characterized in that the turbomachine part (2) comprises at least one flat portion (2a), one annular portion (2b), one curved portion (2c) and / or one perforated portion (2d), in which at least one of the flat (2a), annular (2b), curved (2c) and perforated (2d) portions includes at least one portion of the face (30) on which the honeycomb structure (4) is made.

9. A manufacturing method according to any one of the preceding claims, characterized in that the turbomachine part (2) is selected from a gas flow discharge duct, an annular housing and an acoustic panel.

10. A manufacturing method according to any one of the preceding claims, characterized in that the turbomachine part (2) is made of metallic or composite material.

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