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 a face of the wall, the honeycomb structure comprising at least a first network of cells and at least a first skin covering this first network of cells, the method comprising the following steps of: (a) providing the wall, and (b) producing the honeycomb structure on the face, in which step (b) of producing the honeycomb structure comprises the following sub-steps of: (b1) depositing first plies of composite material by draping to form the first skin, and (b2) forming the first network of cells by additive manufacturing, sub-step (b1) being carried out before or after sub-step (b2). Figure for 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, in particular aircraft parts. More particularly, the present invention relates to a method of 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, in particular an aircraft turbomachine, comprises parts comprising a wall and a honeycomb structure made of composite material on at least a portion of one face of this wall. The honeycomb structure comprises one or more networks of cells and one or more skins covering the network or networks of cells. The honeycomb structure makes it possible in particular to confer mechanical, vibrational and acoustic properties.

[0003] Certain components of a turbomachine may include stiffeners. One drawback of manufacturing the stiffeners is that they can be delicate and time-consuming to assemble onto the turbomachine component (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 component.

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

[0005] Such components may be made of metallic or composite material.

[0006] It is known to produce such turbomachine parts from composite material by the resin transfer molding technique known as RTM (acronym for "Resin Transfer Molding"). Generally speaking, hollow turbomachine parts are preferably produced by RTM. This technique requires the use of a resin injection mold, tarpaulins to envelop in particular the fiber preform intended to form the turbomachine part, an autoclave to carry out in particular the resin polymerization, and cores to produce in particular a hollow portion of the turbomachine part and / or the network of cells. This technique can be tedious and complex to carry out since it requires the use of several tools.

[0007] Concerning the production of the honeycomb structure of the turbomachine part, it is generally formed by manufacturing the cell network and the skin(s) separately, then assembling them with adhesives and finally consolidating the assembly (for example by welding, gluing and the use of other assembly and consolidation tools). When the honeycomb structure is made on the face of a curved wall, the cell network is generally curved and then assembled on this curved wall. One of the disadvantages of this method of manufacturing the honeycomb structure is that it is not suitable for turbomachine parts, for example, of small dimensions (such as a small radius of curvature), of cylindrical shape or generally having a so-called non-developable surface (such as spherical, elliptical, hollow shapes, etc.).

[0008] The term "non-developable surface" means a surface having 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, a casing or an external panel called an internal fixed structure (IFS), a conical nacelle, etc.

[0009] [Fig.l] illustrates an example of a part 1 of cylindrical shape 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 on a circular wall 14 connected to the cylindrical wall 12. Dotted arrows represent connection defects Dr at the level between the first RI and second R2 networks of cells at the level of a cylindrical periphery 16 of the part 1.

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

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

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

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

[0014] For this purpose, the invention relates to a method for manufacturing a turbomachine part, in particular an aircraft part, 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 least one second network of cells. at least a first skin covering this first network of cells, the method comprising the following steps of: (a) providing the wall, and (b) producing the honeycomb structure on at least one part of the face of the wall.

[0015] According to the invention, step (b) of producing the honeycomb structure comprises the following sub-steps: (bi) depositing first plies of composite material by draping to form said at least one first skin, and (b2) forming said at least one first network of cells by additive manufacturing,

[0016] sub-step (bi) being carried out before or after sub-step (b2).

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

[0018] In particular, the draping of composite material plies and additive manufacturing make it possible to form, in a simple and efficient manner, respectively, the skin(s) and the network(s) of cells making up the cellular structure, in particular without constraints on the dimensions of the turbomachine part. Indeed, additive manufacturing makes it possible to print the network(s) of cells directly on all possible dimensions of the skin and / or the face of the wall of the turbomachine part. These dimensions may be 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 cellular structure, in particular by conferring mechanical properties of the stiffness type in addition to the vibrational and acoustic properties so as to reinforce the rigidity and the bending resistance of the part. Indeed, the invention makes it possible to produce both a simple cellular 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 shape (i.e. a wall comprising for example an unconventional curvature with a small radius of curvature, double curvature, etc.). In this way, the cellular structure produced by the method of the invention makes it possible to increase the local stiffness (in particular at the wall) of the turbomachine part.The vibrational properties of the honeycomb structure obtained by the method of the invention make it possible to reinforce the absorption of the different resonance frequencies of the turbomachine in operation to prevent the turbomachine part from entering into resonance. The acoustic properties of the structure. alveolar obtained by the process of the invention make it possible to reduce noise pollution (in particular when the alveolar structure comprises 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 design that is simple to produce, offering very high reliability, and with little penalty in terms of cost, mass and size. In addition, the invention makes it possible to reduce the environmental impact by improving and simplifying the manufacture of the turbomachine part.

[0021] The term “composite material plies” means one or more fibrous layers (or otherwise known as fabrics) which can each 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 plies of composite material to form, in the present application, the skin(s) of the cellular structure.

[0023] The term “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 method according to the invention may comprise one or more of the following characteristics, taken in isolation from one another or in combination with one another:

[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, in which the method comprises a sub-step (b3) of depositing second plies of composite material by draping to form said at least one second skin, this sub-step (b3) being carried out before sub-step (b2) and sub-step (bi) being carried out after sub-step (b2);

[0026] - the alveolar structure comprises at least one second network of alveoli, said at least one at least one first skin covering said first network of cells and said at least one second skin being perforated and interposed between said first and second networks of cells, in which the method comprises a sub-step (b4) of forming said at least one second network of cells by additive manufacturing, this sub-step (b4) being carried out before sub-step (b3);

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

[0028] - the draping of the sub-steps (bj and (b3) are carried out manually or in a manner automated, and the additive manufacturing of sub-steps (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, formed by additive manufacturing;

[0032] - the turbomachine part is chosen from a discharge duct for 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 of composite material and / or the second plies of material composite each have a maximum ply width of about 20 mm or up to about 40 mm; this allows AFP type draping;

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

[0036] The invention may also relate to a turbomachine part comprising a wall and a cellular structure made of composite material on at least a portion of one face of the wall, the cellular structure comprising at least a first network of cells and at least a first skin covering this first network of cells. This turbomachine part may be obtained by the manufacturing method according to one of the particularities of the invention.

[0037] The turbomachine part can be chosen in a non-limiting manner from a gas flow discharge duct, an annular casing, a self-stiffened 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, characteristics and advantages of the present invention will appear more clearly on reading the description of a non-limiting example which follows, with reference to the appended drawings in which:

[0040] [Fig.l] is a perspective view schematically representing a cylindrical-shaped part comprising a honeycomb structure with networks of honeycomb cells according to the prior art;

[0041] [Fig.2] is a perspective and partial view showing a curved cell network of another prior art cell structure;

[0042] [Fig.3] is a partial axial sectional view showing a deformed cell network of another prior art cell structure;

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

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

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

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

[0047] [Fig.7] is a partial sectional schematic of a first example of the alveolar structure according to the invention;

[0048] [Fig.8] is a partial sectional schematic of a second example of the alveolar structure according to the invention;

[0049] [Fig.9] is a partial sectional schematic of a third example of the alveolar structure according to the invention;

[0050] [Fig. 10] is a diagram of a first example of a method for manufacturing 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 sectional view of a network of cells without deformation of the cell structure according to the invention;

[0054] Elements having the same functions in 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 the present application and illustrate examples of a turbomachine part comprising a prior art honeycomb structure.

[0056] The invention applies in a general and non-limiting manner to different types of turbomachine part, in particular aircraft. The turbomachine may be a turboprop or a turbojet.

[0057] The turbomachine may conventionally comprise, from upstream to downstream (relative to the direction of circulation of the gases in the turbomachine), a fan, one or more com pressers, 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 may be a discharge conduit for a gas flow (figures 4a and 4b), an annular casing ([Fig.5]), an acoustic panel or a self-stiffened panel ([Fig.6]).

[0059] The part 2 of the invention can thus be any part of the turbomachine having a wall of complex or simple shape to produce.

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

[0061] The 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] The part 2 may comprise at least one flat portion 2a, one annular portion 2b, one curved portion 2c and / or one perforated portion 2d. The flat 2a, annular 2b, curved 2c and / or perforated 2b portions may be formed on the wall 3. At least one of the flat portions 2a, annular portion 2b, curved portion 2c and perforated portion 2d may comprise 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 the part 2 which may comprise the honeycomb structure 4 produced in particular according to a manufacturing method of the invention.

[0065] [Fig.4a] and 4b illustrate in a non-limiting manner the discharge duct or any other part 2 of the turbomachine having the curved portion 2c. This curved portion 2c may comprise the face 30 on which the honeycomb structure 4 is formed.

[0066] [Fig.5] illustrates in a non-limiting manner the annular casing or any other part 2 of the turbomachine having the annular portion 2b. This annular portion 2a may comprise the face 30 on which the alveolar structure 4 is formed.

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

[0068] [Fig. 6] also illustrates in a non-limiting manner the wall 3 with the perforated portion. 2d with an orifice O. This perforated portion 2d may comprise 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 manner the different possible configurations of the cellular structure 4 of the invention which can be formed on the wall 3 of the part 2 described above (in particular with reference to Figures 4a to 6).

[0070] The cellular structure 4 comprises at least one first network of cells 42 and at least one first skin 44 covering this first network of cells 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 network of alveoli 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 cellular 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 network of cells 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 alveolar structure 4 may form a so-called 2DOF structure (an English acronym for “two degree of freedom” to designate two degrees of freedom and acoustic attenuation according to two frequencies, such as low and high frequencies). This 2DOF structure according to a third example may further comprise at least one second network of alveoli 46, in which the first skin 44 covers the first network of alveoli 42 and the second skin 48 is perforated and interposed between the first 42 and second 46 networks of alveoli. In the example of [Fig. 9], the second network of alveoli 46 may be located on the face 30. The second skin 48 may comprise perforations 480.The alveolar structure 4 according to the third example makes it possible to reinforce the acoustic properties of the room 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 alveolar networks.

[0074] The first network of cells 42 and / or the second network of cells 46 may comprise alveolar cells which may, in a non-limiting manner, be of polygonal shape. These polygonal cells may be of triangular, quadrilateral, pentagonal or hexagonal shape and / or of rounded shape. Advantageously, the alveolar cells of the first network of cells 42 and / or of the second network of cells 46 may each have side walls which have a rounded (or otherwise said curved) shape, for example on at least one of their side wall ends.

[0075] Advantageously, the alveolar structure 4 can comprise at least one annular section 40a, 40b which can be arranged upstream and / or downstream of the skins 44, 48 and the alveolus networks 42, 46. [Fig. 5] illustrates in a non-limiting manner two sections 40a, 40b may have a chamfer and may be monolithic (or otherwise said solid). As a variant, this or these annular sections 40a, 40b may be acoustically treated by comprising, for example, a third network of cells having smaller dimensions than those of the first and / or second networks of cells.

[0076] The first network of cells 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 network of cells 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 identical to 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 thickness E48 of between 0.4 and 7 mm. Preferably, the fourth thickness E48 may be between 0.4 and 2.5 mm. The fourth thickness E48 may be identical to or different from the third thickness E44.

[0080] The cellular structure 4 is made of composite material. 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. The fibrous preform may comprise carbon fibers, glass fibers, ceramic fibers (such as silicon carbide, glass, or aramid), polyamide fibers, metal fibers, oxide fibers, or a mixture of at least two of these fibers. The fibers of the composite material of the cellular structure 4 (in particular the first 46 and / or second 46 networks of cells) may be short fibers or long fibers.

[0081] In particular, the first skin 44 can be formed of first composite material folds. The second skin 48 can be formed of second composite material folds. The first and second composite material folds 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, polyepoxy, polyimide, polybismaleimide, polyurethane, polyester, polyetherimide (PEI), Polyaryletherketone family (PAEK, such as polyetheretherketone PEEK, polyetherketone PEK, polyetherketoneketone PEKK,...), or vinyl ester.

[0083] The present application will now describe a method of manufacturing the 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 different examples of embodiment of the method of the invention.

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

[0085] The method comprises the following steps: (a) provision of wall 3, and (b) production of the honeycomb structure 4 on at least one portion of the face 30 of the wall 3.

[0086] One of the particularities of the invention is that step (b) of producing the cellular structure 4 comprises the following sub-steps: (bi) laying down plies of composite material by draping to form the first skin 44, and (b2) formation of the first network of cells 42 by additive manufacturing.

[0087] Substep (bi) can be performed before or after substep (b2). This is represented by a double arrow in [Fig. 10].

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

[0089] The method for manufacturing the part 2 may comprise a sub-step (b3) of depositing second plies of composite material by draping to form the second skin 48 of the cellular structure 48, as illustrated in FIGS. 11 and 12. This sub-step (b3) may be carried out before the sub-step (b2).

[0090] The method for manufacturing the part 2 may comprise a sub-step (b4) of forming by additive manufacturing the second network of cells 46 of the cellular structure 48, as illustrated in [Fig. 12]. This sub-step (b4) may be carried out before the sub-step (b3).

[0091] The alveolar structure 4 may comprise at least one of the flat portions 2a, annular 2b, curved 2c and perforated 2c. At least one of these flat 2a, annular 2b, curved 2c and perforated 2c portions may comprise (or form) at least one portion of the face 30 on which the cellular structure 4 is produced according to the method of the invention (in particular by sub-steps (bi) and (b2), and / or sub-step (b3) and possibly sub-step (b4)).

[0092] In sub-step (bi) and / or sub-step (b3), the draping of the first and / or second plies of composite material can be carried out manually or automatically. For example, sub-step (bi) and / or sub-step (b3) can be carried out by the AFP technique (acronym for “Automated Fiber Laying”), the ATL technique (acronym for “Automated Tape Laying”) or the P&P technique (acronym for “Pick & Place” for gripping and positioning system). The AFP draping allows the first and / or second plies of composite material to be deposited, preferably in parallel and simultaneously, to form the first skin 44 and possibly the second skin 48. The first and / or second plies of composite material deposited can each have a ply width of a few millimeters to a few tens of millimeters.For example, this AFP draping pleat width can be at most about 20 mm or up to about 40 mm.

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

[0094] The first and / or second plies of composite material may be previously consolidated (or otherwise 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 may be an oven, an autoclave, a vacuum tank and / or a compression press.

[0095] In sub-step (b2) and / or sub-step (b4), additive manufacturing can be carried out by laser fusion on a powder bed (LBM acronym for “Laser Beam Melting”), or by extrusion (EAM acronym for “Extrusion Additive Manufacturing”)•

[0096] Powder bed additive manufacturing makes it possible to produce parts of complex shape, such as the first 42 and second 46 cell networks 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 possible to more easily form and control the different possible shapes of the cell network 42, 46 (in particular of these polygonal cells). Thus, polygonal cells (for example of triangular, quadrangular, pentagonal or hexagonal shape and / or of rounded shape) can be formed by additive manufacturing.

[0097] LBM additive manufacturing makes it possible to selectively consolidate layers of powder in order to constitute, layer by layer, the first 42 and second 46 three-dimensional cell networks.

[0098] EAM additive manufacturing makes it possible to deposit a continuous filament of composite or thermoplastic material to build the first 42 and second 46 three-dimensional cell networks layer by layer.

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

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

[0101] These steps of producing the honeycomb structure 4 according to the second example are shown in [Fig.11].

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

[0103] These steps of producing the honeycomb structure 4 according to the second example are shown in [Fig.12].

[0104] The second skin 48 may be perforated with the perforations 480 before or after the draping of sub-step (b3).

[0105] With reference to [Fig. 13], the formation of the first network of cells 42 and / or the second network of cells 46 by additive manufacturing, in particular on the annular portion 2b or curved portion 2b, makes it possible to form the side walls of the polygonal cells without deformation. In other words, the side walls of the cells al veolar cells of the alveolar networks 42, 46 have constant thicknesses regardless of the curvature of the wall 3. Indeed, these lateral walls of alveolar cells (in particular of polygonal shape) which are curved, can be distant from each other via a clearance 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 the part 2 produced according to the method of the invention.

[0107] According to a first test, the bending force at break (measured in Newton 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 particularly, 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 has 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 (acronym for “Fused Filament Fabrication” to designate a deposition of fused filament) with a PEI thermoplastic resin of the Ultem® 1010 type. This second specimen EA2 has a greater bending force of approximately 65 N.

[0109] A third test specimen EA3 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 FFF additive manufacturing with a PEI thermoplastic resin of the Ultem® 9085 type. This third specimen EA3 has an even greater bending force of approximately 140 N.

[0110] Thus, the results of the first test allow us to conclude that the part 2 comprising the first 42 or second 46 network of cells produced by additive manufacturing, significantly increases the bending force. The choice of the composite material also makes it possible to reinforce the bending force of the part 2.

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

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

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

[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 test specimen EA6 has a bending force which is greater than 2.5 times for a reduced weight of approximately 0.6 compared to the fourth test specimen EA4.

[0115] The fifth EA5 and sixth EA6 test specimens exhibit greater bending force for 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 sensitively to the part 2 formed according to the method of the invention) presents a significant gain in rigidity.

Claims

Claims

1. A method of manufacturing a part (2) of a turbomachine, in particular an aircraft part, the part (2) of the turbomachine 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) comprising at least a first network of cells (42) and at least a first skin (44) covering this first network of cells (42), the method comprising the following steps of: (a) providing the wall (3), and (b) producing the honeycomb structure (4) on the at least a portion of the face (30) of the wall (3), characterized in that step (b) of producing the honeycomb structure (4) comprises the following sub-steps of: (bi) depositing first plies of composite material by draping to form said at least a first skin (44), and (b2) forming said at least a first network of cells (42) by additive manufacturing,the sub-step (bj being carried out before or after the sub-step (b2).,

2. Manufacturing method according to claim 1, characterized in that the cellular 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), in which the method comprises a sub-step (b3) of depositing second plies of composite material by draping to form said at least one second skin (48), this sub-step (b3) being carried out before sub-step (b2) and sub-step (bi) being carried out after sub-step (b2

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

4. Manufacturing method according to claim 3, characterized in that the draping of sub-steps (bi) and (b3) are carried out manually or automatically, and the additive manufacturing of sub-steps (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) of between 0.2 and 55 mm.

6. 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) of between 0.4 and 7 mm.

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

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

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

10. 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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