METHOD FOR MANUFACTURING A HONEYCOMB STRUCTURE FOR A PARTICULAR COMPONENT OF AN AIRCRAFT TURBOMACHINE

Abstract

The invention relates to a method for manufacturing a honeycomb structure for a part, in particular for an aircraft turbomachine, this honeycomb structure comprising a grid of cells (86), a first skin (82) of composite material covering the grid (86), and optionally a second skin (84) of composite material having the grid (86) positioned between the first and second skins, the method being characterized in that it comprises the steps of: (a) creating a first stack (820) of fiber layers by draping so as to form the first skin, (b) depositing at least one first interface film (800) by draping onto the first skin, (c) positioning the grid of cells (86) on the first interface film, (d) optionally depositing at least one second interface film (802) by draping onto the grid (86), and (e) optionally creating a second stack (840) of fiber layers by draping so as to form the second skin.Figure for the abbreviation: Figure 11.

Description

Title of the invention: METHOD FOR MANUFACTURING A HONEYCOMB STRUCTURE FOR A PARTICULAR COMPONENT OF AN AIRCRAFT TURBOMACHINE technical field

[0001] The invention relates to the field of honeycomb structures for a part, in particular for an aircraft turbomachine. More particularly, the present invention relates to a method for manufacturing a honeycomb structure for a part, in particular for an aircraft turbomachine. Technical background

[0002] A honeycomb structure, also known as a cellular structure, comprises one or more skins covering a network of cells. This network of cells comprises alveolar cells that are joined to one another and arranged in a predetermined pattern. This arrangement gives the structure high mechanical properties, in particular high mechanical strength, while remaining lightweight.

[0003] The honeycomb structure can be made of metallic and / or composite material.

[0004] The honeycomb structure, particularly for aircraft turbomachinery parts, is typically produced by manufacturing the honeycomb grid and the skins separately, then assembling them to form the whole (for example, by welding, bonding, and the use of other assembly and consolidation tools). However, this method of manufacturing the honeycomb structure can be complex because it requires a large number of operations and tooling, which are often not very automated.

[0005] 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 for a part, in particular of an aircraft turbomachine. Summary of the invention

[0006] The present invention offers a simple, effective and economical solution to the aforementioned disadvantages of the prior art.

[0007] To this end, the invention relates to a method of manufacturing a honeycomb structure for a part, in particular of an aircraft turbomachine, this honeycomb structure comprising a network of honeycombs, a first skin of composite material covering the network of honeycombs, and optionally a second skin of composite material and arranging the network of honeycombs between said first and second skins.

[0008] According to the invention, the method comprises the steps of: (a) create an initial layering of several layers of fibre by draping so as to form the first skin, (b) deposit at least one first interface film by draping it onto the first skin, (c) position the honeycomb grid on the first interface film, (d) optionally deposit at least a second interface film by draping it over the cell array, and (e) optionally carry out a second stacking of several layers of fibre by draping so as to form the second skin.

[0009] Thus, this solution makes it possible to achieve the aforementioned objective. In general, the process according to the invention simplifies the production of a honeycomb structure by using the draping technique to deposit both layers of fibers and at least one interface film. Furthermore, draping can be compatible when using a thermoplastic matrix to produce the honeycomb structure.

[0010] Furthermore, draping can be carried out manually or automatically (for example by a suitable machine). For example, draping can be carried out by the AFP technique (English acronym for "Automated Fiber Placement" for automated fiber placement), the ATL technique (English acronym for "Automated Tape Laying" for automated tape laying) or the P&P technique (English acronym for "Pick&Place" for a picking and positioning system).

[0011] 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 environmental impact by improving and simplifying the manufacturing of components (i.e., a honeycomb structure) for an aircraft turbomachine.

[0012] The term "draping" refers to the successive deposition, by superposition and stacking, of several layers of composite material (such as layers of fibers and the interface film(s)) to form, in the present application, the skin(s) of the honeycomb structure. The layers can be draped in different orientations (such as with an orientation angle of 0°, 45°, -45° (or 135°); 90°).

[0013] The manufacturing process according to the invention may include one or more of the following features, taken individually or in combination with each other:

[0014] - that at least one of the steps (a), (b), (c), (d) and (e) comprises a substep compaction (ai5 b,, c, d,, e) of the fiber layers of the first and / or second stacks and of the first and / or second interface films, such as with a roller of compaction which is for example integrated into a draping device for sub-steps (ai, bi5 di5 e,), or with a pressure device for sub-step (c,);

[0015] - steps (a) and (e) each comprise a cooking substep (au, eü) of the first and second stackings to form respectively the first and second skins;

[0016] - at least one of the sub-steps (aü, eü) of cooking is carried out during draping first and / or second stacks with a heating device integrated into the draping device, in which the first and / or second stacks are heated for example by a laser source, a plasma torch, an ultraviolet lamp or a flash lamp;

[0017] - at least one of the sub-steps (aü, eü) of cooking is carried out after the draping of the first and / or second stacks with an external heating device, in which the first and / or second stacks are heated, for example, in a heating device;

[0018] - at least one of steps (a) and (e) is carried out by draping at least one of the layers of fibers from the first and / or second stacks following a different direction than that of the other fiber layers of the corresponding stack;

[0019] - before step (c), the first skin and the first interface film obtained in step (b) are cooled with a cooling device, for example, induction type, forced air type or with a heat transfer fluid;

[0020] - at least one of the first and second skins comprises perforations, in which process further comprises a perforation step (f) of one of the first and second skins which is carried out after step (e);

[0021] - the fiber layers of at least one of the first and second stacks include pre-impregnated fibers of a first thermoplastic material;

[0022] - the honeycomb network is made of metal, such as aluminum, thermoplastic, in paper or cardboard, in which the paper or cardboard is, for example, impregnated with a phenolic or aramid resin;

[0023] - at least one of the first and second interface films comprises a second material thermoplastic;

[0024] - the second thermoplastic material has a softening temperature lower than that of the first thermoplastic material;

[0025] — at least one of the steps (a) to (e) is carried out manually or in a automated;

[0026] — the first thermoplastic material is chosen from the polyetherketone family (PEK) or polyaryletherketone (PAEK), such as low-melting-point polyaryletherketone (LM-PAEK), polyetheretherketone (PEEK), polyetheretherketoneketone (PEEKK), polyetherketoneketone (PEKK), polyetherketoneetherketoneketone (PEKEKK), etc.; polyphenylene sulfide (PPS); and a thermoplastic of an amorphous nature (such as polyetherimide (PEI), polyethersulfone (PESU), polyimide (TPI), polyamide-imide (PAI), polysulfone (PSU), etc.);

[0027] — the second material is chosen from the polyetherketone (PEK) family or polyaryletherketone (PAEK), such as low melting point polyaryletherketone (LM-PAEK), polyetheretherketone (PEEK), polyetheretherketoneketone (PEEKK), polyetherketoneketone (PEKK), polyetherketoneetherketoneketone (PEKEKK), etc.; polyphenylene sulfide (PPS); and amorphous thermoplastics (such as polyetherimide (PEI), polyethersulfone (PESU), polyimide (TPI), polyamide-imide (PAI), polysulfone (PSU), etc.);

[0028] — the second thermoplastic material is free of additional filler(s), such as fibers or components in the form of particles;

[0029] — the first interface film and / or the second interface film is (or are) a film adhesive;

[0030] — the honeycomb network is made of metal (such as aluminum), thermoplastic, in paper (for example impregnated with a phenolic or aramid resin) or in cardboard (for example impregnated with a phenolic or aramid resin);

[0031] — the honeycomb network is made of amorphous thermoplastic (such as the polyetherimide (PEI)) or of semi-crystalline nature (such as polyaryletherketone (PAEK));

[0032] — the alveolar network comprises polygonal cells, for example of the shape triangular, quadrangular, pentagonal or hexagonal and / or rounded;

[0033] — the part, in particular of the aircraft turbomachine, is an annular housing, a acoustic panel or a self-stiffening panel.

[0034] The invention also relates to a honeycomb structure for a part, in particular of an aircraft turbomachine, this honeycomb structure being produced by the manufacturing process having any one of the characteristics described below.

[0035] The alveolar structure can therefore include the network of alveoli, the first skin of material covering the alveolar network, and possibly the second skin of composite material arranging the alveolar network between said first and second skins.

[0036] The alveolar structure may further comprise at least the first interface film located between the alveolar network and the first skin of composite material.

[0037] Optionally, the honeycomb structure may further include at least the second interface film located between the honeycomb network and the second skin made of composite material.

[0038] The invention may further relate to a part, in particular of an aircraft turbomachine (or an aircraft nacelle), comprising at least one honeycomb structure as described above.

[0039] This part can be an annular housing, an acoustic panel or a self-stiffening panel.

[0040] The invention may also relate to an aircraft turbomachine comprising at least one part as described above.

[0041] The invention may also relate to an aircraft nacelle comprising at least one part as described above.

[0042] This nacelle can extend around the turbomachine. Brief description of the figures

[0043] The present invention will be better understood and other details, features and advantages of the present invention will become more apparent upon reading the description of a non-limiting example that follows, with reference to the accompanying drawings in which:

[0044] Fig. 1 is a schematic perspective view of an aircraft turbomachine,

[0045] [Fig.2] is a schematic perspective and axial section view of a first example of a honeycomb structure according to the invention for a part for example of the turbomachine of [Fig.1],

[0046] [Fig.3] is a schematic perspective and partial view of a second example of a honeycomb structure according to the invention for a part, for example, of the turbomachine of [Fig.1],

[0047] [Fig.4] is a partial schematic axial cross-sectional view of the alveolar structure of [Fig.2],

[0048] [Fig. 5] is a block diagram representing manufacturing steps of the alveolar structure of [Fig. 3] or 4,

[0049] [Fig.6] is a schematic axial cross-sectional view of an installation according to the invention for producing the honeycomb structure of [Fig.3] or 4, or the manufacturing steps of [Fig.5],

[0050] [Fig.7] is a schematic axial cross-sectional view representing a draping step of several layers of fibers to form a first skin of the alveolar structure of [Fig.3] or 4,

[0051] [Fig.8] is a schematic axial cross-sectional view representing a step of depositing a first interface film on the first skin obtained in [Fig.7],

[0052] [Fig.9] is a schematic axial cross-sectional view representing a positioning step of a grid of cells on the first interface film obtained in [Fig.8],

[0053] [Fig. 10] is a schematic axial cross-sectional view representing a step of depositing a second interface film onto the honeycomb network obtained in [Fig. 9],

[0054] [Fig. 11] is a schematic axial cross-sectional view representing a draping step of several layers of fibers onto the second interface film obtained in [Fig. 10] and forming a second skin of the alveolar structure,

[0055] [Fig. 12] is a schematic axial cross-sectional view representing a perforation step of the first skin of the alveolar structure obtained in [Fig. 11].

[0056] Elements having the same functions in the different implementations have the same references in the figures. Detailed description of the invention

[0057] By convention, in the following description, the terms "longitudinal" and "axial" refer to the orientation of structural elements extending along a longitudinal axis (such as that of a turbomachine). The terms "radial" or "vertical" refer to the orientation of structural elements extending in a direction perpendicular to the longitudinal axis. The terms "inner" and "outer," and "internal" and "external," are used with reference to positioning relative to the longitudinal axis. Thus, a structural element extending along the longitudinal axis has an inner face facing the longitudinal axis and an outer surface opposite its inner surface. Similarly, the terms "upstream" and "downstream" are defined with respect to the direction of gas flow in the turbomachine.

[0058] The invention applies generally and not limited to different types of part 8, in particular for an aircraft turbomachine 10.

[0059] The turbomachine 10 can be a turboprop or a turbojet.

[0060] Figure 1 illustrates an example of a turbomachine 10 extending around an axis longitudinal X.

[0061] The turbomachine 10 can conventionally comprise, from upstream to downstream, a blower 1, one or more compressors (such as a low pressure compressor 2 and a high pressure compressor 3), a combustion chamber 4, one or more turbines (such as a low pressure turbine 5 and a high pressure turbine 6) and optionally an exhaust nozzle.

[0062] The turbomachine 10 may include several annular housings, such as a blower housing 7a extending around the blower 1, and an intermediate housing 7b extending around the low-pressure compressor 2 in the example of [Fig.1].

[0063] The invention finds an advantageous but not exclusive application in one or more parts 8 from an aircraft turbomachine 10 (such as a turbojet or turboprop aircraft type) or from an aircraft nacelle (such as an element or module of the thrust reverser). This nacelle (not shown in the figures) can extend around the turbomachine 10.

[0064] For example, and without limitation, the part(s) 8 may (or may) be an annular housing (such as the blower housing 7a and / or the intermediate housing 7b of [Fig.1]), an acoustic panel or a self-stiffening panel.

[0065] Part 8 may include at least one alveolar structure 80.

[0066] The part 8 of the invention can thus be any part, for example of a turbomachine 10 and / or nacelle, comprising the honeycomb structure 80.

[0067] The honeycomb structure 80 comprises a network of cells 86 and a first skin 82 made of composite material. The first skin 82 covers the network of cells 86. This first skin 82 may advantageously include perforations 822, to form a perforated skin, referred to as an acoustic skin. Alternatively, the first skin 82 may be a solid skin (or, in other words, without perforations).

[0068] Fig. 2 illustrates in a non-limiting way a first configuration of the alveolar structure 80 comprising only the first skin 82 covering the alveolar network 86. In this first configuration, the alveolar structure 80 is said to be semi-open since alveolar cells composing the alveolar network 86 can be at least partially open to the outside of this alveolar structure.

[0069] By way of example, the first skin 82 (in particular perforated) may be located at the level of a flow channel of an airflow of the turbomachine, and the network of cells 86 may be located at the level of an internal or external surface of the part 8, particularly when this part 8 is an annular casing or an acoustic panel of the turbomachine. This internal or external surface of the part 8 may be located opposite the first skin 82 and may thus form a solid skin covering the network of cells 86.

[0070] The alveolar structure 80 may comprise at least two skins 82, 84 of composite material, respectively, the first skin 82 and a second skin 84; in which the alveolar network 86 is located between these two skins 82, 84.

[0071] The second skin 82 may be optional, in particular when the alveolar structure 80 is semi-open, as described above.

[0072] One of the first 82 and second 84 skins may advantageously include perforations 822 to form an acoustic skin, and the other of the first 82 and second 84 skins may form a solid skin (or, in other words, without perforations). Alternatively, the first 82 and second 84 skins may be solid.

[0073] Figures 3 and 4 illustrate, in a non-limiting manner, a second configuration of the alveolar structure 80 comprising the first 82 and second 84 skins, and the network of alveoli 86 located between these first 82 and second 84 skins. This second configuration is called sandwich and forms a closed alveolar structure.

[0074] By way of example, the first skin 82 (in particular perforated) can be located at the level of a flow vein of an air flow of the turbomachine and the second skin 84 (whether perforated or solid) can be located at the level of an internal or external surface of the part 8, in particular when this part 8 is an annular casing or an acoustic panel of the turbomachine.

[0075] Advantageously, the alveolar structure 80 can include at least one interface film 800, 802. This interface film 800, 802 allows one or more skins 82, 84 to be connected to the alveolar network 86.

[0076] On the example of [Fig.2], the alveolar structure 80 can include a first interface film 800 allowing the first skin 82 to be connected to the alveolar network 86.

[0077] In the example of Figures 3 and 4, the alveolar structure 80 can comprise the first interface film 800 and a second interface film 802. These first 800 and second 802 interface films allow the first 82 and second 84 skins to be connected, respectively, to the alveolar network 86. As illustrated in [Fig. 4], the first interface film 800 is intercalated between the first skin 82 and the alveolar network 86, and the second interface film 802 is intercalated between the second skin 84 and the alveolar network 86.

[0078] The first interface film 800 and / or the second interface film 802 may (or can) be an adhesive film.

[0079] In an alternative not shown in the figures, the honeycomb structure 80 may comprise several networks of cells 86 superimposed one on top of the other, and optionally delimited from each other by one or more intermediate skins (commonly called "septum"). The intermediate skin(s) may be made of composite material, in particular in a manner similar to the first and second skins 82, 84.

[0080] The first skin 82 can be formed from a first stacking 820 of several layers of fibers (hereafter referred to as first layers of fibers).

[0081] Each of the first fiber layers may comprise unidirectional fibers which may be oriented in directions (or orientations) different from the fibers of the other first fiber layers of this first stack 820.

[0082] The first skin may have a first thickness E82 which may be less than or equal to 10 mm. This first thickness E82 may be between 0.5 and 5 mm.

[0083] The second skin 84 can be formed from a second stack 840 of several layers of fibers (hereafter referred to as second layers of fibers).

[0084] Each of the second fiber layers may comprise unidirectional fibers which may be oriented in different directions from the fibers of the other second fiber layers of this second stack 840.

[0085] The second skin 84 may have a second thickness E84 which may be less than or equal to 10 mm. This second thickness E84 may be between 0.5 and 5 mm.

[0086] The second layer E84 of the second skin 84 may be different or identical to the first layer E82 of the first skin 82.

[0087] The first stack 820 and / or the second stack 840 may (or may) comprise pre-impregnated fibers of a first thermoplastic material.

[0088] The first stack 820 and / or the second stack 840 may (or 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.

[0089] The first thermoplastic material can be chosen from the following materials: - the polyetherketone (PEK) or polyaryletherketone (PAEK) family, such as low-melting-point polyaryletherketone (LM-PAEK), polyetheretherketone (PEEK), polyetheretherketoneketone (PEEKK), polyetherketoneketone (PEKK), polyetherketoneetherketoneketone (PEKEKK), etc., - polyphenylene sulfide (PPS), and - a thermoplastic of an amorphous nature (such as polyetherimide (PEI), polyethersulfone (PESU), polyimide (TPI), polyamide-imide (PAI), polysulfide (PSU), etc.).

[0090] Only the first skin 82 may include perforations 822. These perforations 822 may open into the alveolar network 86 (particularly at the level of the alveolar cells described below). Figure 12 illustrates, in a non-limiting manner, perforations 822 formed on the first skin 82.

[0091] Alternatively, perforations can be formed only on the second skin 84 and thus form an acoustic skin, while the first skin 82 forms the solid skin.

[0092] The first interface film 800 and / or the second interface film 802 may comprise a second thermoplastic material.

[0093] The second thermoplastic material can be chosen from the following materials: - the polyetherketone (PEK) or polyaryletherketone (PAEK) family, such as polyetherketone (PEK), polyetheretherketone (PEEK), polyetheretherketoneketone (PEEKK), polyetherketoneketone (PEKK), polyetherketoneetherketoneketone (PEKEKK), etc., - phenylene polysulfide (PPS), and - a thermoplastic of an amorphous nature (such as polyetherimide (PEI), polyethersulfone (PESU), polyimide (TPI), polyamide-imide (PAI), polysulfone (PSU), etc.).

[0094] The second thermoplastic material of at least one of the first and second interface films 800, 802 may have a different softening temperature than that of the first thermoplastic material of at least one of the first and second stacks 820, 840.

[0095] In particular, the softening temperature of the second thermoplastic material may be lower than that of the first thermoplastic material. This makes it possible to heat the interface film(s) more easily and quickly at relatively low temperatures and with less heating energy input, to create a strong bond between the skin(s) 82, 84 and the honeycomb network 86.

[0096] The term "softening temperature" means the melting temperature in the case of semi-crystalline thermoplastics, or the glass transition temperature in the case of amorphous thermoplastics.

[0097] Preferably, the softening temperature of the second thermoplastic material may be lower than that of the first thermoplastic material.

[0098] By way of example, the softening temperature of the second thermoplastic material may be less than 350°C. This softening temperature of the second material may be between 170 and 350°C, preferably around 210°C.

[0099] The softening temperature of the first thermoplastic material may be less than 350°C. This softening temperature of the first material may be between 170 and 350°C, preferably around 307°C.

[0100] The softening temperature may depend on the nature (such as semi-crystalline or amorphous) of the first and second thermoplastic materials. For example, the softening temperature of the first and / or second thermoplastic materials being semi-crystalline (e.g., LM-PAEK, PEEK, or PEKK) may be between 300 and 350°C. As another example, the softening temperature of the first and / or second thermoplastic materials being amorphous (e.g., PEI and PSU) may be between 170 and 250°C.

[0101] Advantageously, the second thermoplastic material (of the first interface film 800 and / or the second interface film 802) may be free of additional filler(s), such as fibers or components in the form of particles

[0102] The first interface film 800 may have a third thickness E8Oo which is less than 0.5 mm. Preferably, this third thickness E8Oo may be between 0.05 and 0.5 mm.

[0103] The second interface film 802 may have a fourth thickness E802 which is less than 0.5 mm. Preferably, this fourth thickness E802 may be between 0.05 and 0.5 mm.

[0104] The fourth layer E802 of the second interface film 802 can be identical to the third layer E800 of the first interface film 800.

[0105] The first interface film 800 or the second interface film 802 may include perforations ([Fig. 12]). These perforations may open into the alveolar network 86 (particularly at the level of the alveolar cells).

[0106] The alveolar network 86 may include alveolar cells which may, without limitation, be polygonal in shape. These polygonal cells may be triangular, quadrangular, pentagonal or hexagonal and / or rounded in shape.

[0107] The cell array 86 may have a fifth thickness E86 which may be less than or equal to 50 mm. Preferably, this fifth thickness E86 may be between 20 and 40 mm. Even more preferably, the fifth thickness E86 may be about 30 mm, as proposed in the NIDA cell array

[0108] The honeycomb structure can be made of metal (such as aluminum), thermoplastic, paper (for example, impregnated with a phenolic or aramid resin), or cardboard (for example, impregnated with a phenolic or aramid resin). Preferably, the honeycomb structure 86 can be made of amorphous thermoplastic (such as PEI) or semi-crystalline thermoplastic (such as the PAEK family or the polyetherketone family).

[0109] The honeycomb structure 80 can be made entirely of composite material, particularly when the honeycomb network 86 is made of thermoplastic. Alternatively, the honeycomb structure 80 can be made of composite and metallic material, particularly when the honeycomb network 86 is made of metal and the skins 82, 84 are made of composite material.

[0110] With reference to figures 6 to 12, the present application will now describe an installation 9 for producing the alveolar structure 80 described above.

[0111] Figure 6 illustrates an example of an installation 9 that can operate automatically. This installation 9 may include at least one of the following elements: - a mold 90 (or generally a support), preferably having a flat or curved shape, which serves as a support for the production of the honeycomb structure 80, - a draping device 92 that allows the layers of fibers and / or the interface film(s) 800, 802 to be deposited. - a compaction roller 94 which allows compaction and the application of sufficient pressure to apply (or deposit and adhere) the layers of fibers to each other and / or the interface film(s) 800, 802 with good anchoring to the cell network 86, - a pressure application device (not shown in the figures) which allows compaction and the application of (so-called light) pressure, preferably less than that of the compaction roller 94, on the network of cells 86, - a heating device 96 which allows the first and second stacks 820, 840 to be consolidated by cooking (and possibly to heat the interface film(s) 800, 802), - an external heating device (not shown in the figures) which also allows the first and second stacks 820, 840 to be consolidated by cooking (and possibly to heat the interface film(s) 800, 802), - a cooling device 98 which allows the mold 90 and the components on this mold 90 to be cooled (such as the first stack 820 and the first film 800 with reference to [Fig. 9]), and - a perforation device 99 which allows perforations to be formed on the first skin 82 (or second skin 84) and the first interface film 800 (or the second interface film 802) ([Fig. 12]).

[0112] The mold 90 can be heated by a hot air flow Fc for example up to a maximum temperature of about 300°C.

[0113] The mold 90 can be heated by the external heating device. This external heating device can be integrated into the mold 90 to heat the mold 90, so that the deposited fiber layers adhere to each other. This external heating device can be self-contained.

[0114] The mold 90 can be cooled, for example, to a maximum temperature of approximately 20°C. The mold 90 can be cooled by the absence of heating and / or by the cooling device 98.

[0115] The draping device 92 can move in the installation 9 in a direction SD. This direction SD can vary in particular according to the draping orientation (or direction) of the fiber layers of the first and / or second stacks 820, 840, and possibly of the interface film(s) 800, 802.

[0116] The compaction roller 94 can be integrated into the draping device 92. In particular, this draping roller 94 can be located on one end of the draping device 92 (figures 6 to 12).

[0117] The pressurization device, for example, of the interface film(s) 800, 802, can be operated manually by an operator or automatically. This pressurization device pressure can use a flexible membrane (or in other words a bladder) allowing a predefined pressure to be applied to the network of alveoli 86.

[0118] The heating device 96 can be integrated into (or attached to) the draping device 92. This heating device 96 allows heating in particular of the first and second stacks 820, 840 (and possibly the interface film(s) 800, 802) by a laser source, a plasma torch, an ultraviolet (UV) lamp or a flash lamp.

[0119] The heating device 96 can apply a flow of hot air Fc which is heated for example by the laser source, the plasma torch or the flash lamp.

[0120] The heating device 96 can heat up to a maximum temperature of 500°C, in particular for heating the fiber layers and / or the interface film(s). Preferably, the heating device 96 can heat between 300 and 500°C.

[0121] The external heating device differs in particular from the heating device 96 illustrated by way of example in Figures 6 to 12. The external heating device integrated into the mold 90 forms a self-contained heating unit. For example, the external heating device can perform under-press heating.

[0122] The cooling device 98 can be of the induction type, the forced air type, or with a heat transfer fluid. This cooling device 98 can be connected to the mold 90.

[0123] The perforation device 99 can move in the installation 9 in a direction SP which may be similar to that of the draping device 92. This perforation device 99 can move in several directions including the direction SP.

[0124] With reference to Figures 5 to 12, the present application will now describe a method for manufacturing the honeycomb structure 80 described above. This manufacturing method can be implemented with the installation 9 described above.

[0125] Figure 5 illustrates steps in the manufacturing process of the alveolar structure 80, in which optional steps are represented by dotted lines.

[0126] The manufacturing process according to the invention comprises the steps of: (a) to carry out the first stacking 820 of several first layers of fibres by draping so as to form the first skin 82, (b) deposit at least the first interface film 800 by draping it onto the first skin 82, (c) position the honeycomb grid 86 on the first interface film 800, (d) optionally deposit at least the second interface film 802 by draping it over the honeycomb array (86), and (e) optionally carry out the second stacking 840 of several second layers of fibres by draping so as to form the second skin 84.

[0127] At least one of the steps (a), (b), (c), (d) and (e) can be carried out manually or automatically, in particular with the installation 9. By way of example, automated draping, in particular of at least one of the steps (a), (b), (d) and (e), can be carried out according to one of the techniques AFP, ATL and P&P.

[0128] With reference to [Fig.7], step (a) can be carried out by the draping device 92 which makes it possible to carry out the first stacking 820 by draping the first layers of fibers onto the mold 90.

[0129] During the draping in step (a), the mold 90 can be heated, in particular, up to a maximum temperature of approximately 300°C. This allows the first stack 820 to be at least partially consolidated by baking, and / or to maintain at least partial consolidation of the first stack 820 by baking.

[0130] In step (a), the heating device 96 can heat, in particular, up to a maximum temperature of approximately 500°C. This also makes it possible to consolidate, at least partially, or entirely, the first stack 820 by firing (particularly in the case of in situ consolidation (by firing) described below).

[0131] Step (a) can be carried out by draping the first fiber layers of the first stack 820 in a direction (or orientation) different from that of the other first fiber layers of this first stack 820. This makes it possible to form the first stack 820 with the first fiber layers crossed with each other. This crossed configuration ensures that stresses are transferred in all directions.

[0132] The cross configuration can be obtained by draping the first layers of fibers in different directions with different orientation angles. For example, the orientation angles of the first layers of fibers can be 0° and 90° in the cross configuration.

[0133] Alternatively, step (a) can be carried out using a so-called quasi-isotropic (QI) draping method. In this case, the first layers of fibers can be draped in different directions, for example with orientation angles chosen from the values ​​of 0°, 45°, -45° (or 135°) and 90°.

[0134] In step (a), the first layers of fibers of the first stack 820 can be deposited in the form of strips.

[0135] With reference to [Fig. 8], step (b) can be carried out by the draping device 92, which is notably similar to that of step (a). One or more first interface film(s) 800 can be deposited during this step (b).

[0136] During the draping in step (b), the mold 90 can be heated, in particular up to a maximum temperature of approximately 300°C. This allows the first stack 820 to continue to be consolidated by baking, at least partially, and / or to maintain a consolidation by cooking at least partial of the first stack 820. Indeed, the heating in step (b) by the external heating device ensures good crystallinity and good consolidation by cooking of the first stack 820 draped on the mold 90, and facilitates the change of state of the first interface film 800 deposited which is intended to attach to the cell network 86.

[0137] In step (b), the heating device 96 can heat, in particular, up to a maximum temperature of approximately 500°C. This also allows the first stack 820 to continue consolidating by baking to ensure good cohesion and crystallinity (or other material properties) of the fiber layers, and / or to maintain at least partial consolidation by baking of the first stack 820. This step (b) also facilitates the change of state of the deposited interface film 800 for easy adhesion of the interface film 800 to the first stack 820.

[0138] The first 800 interface film can be deposited in strip form.

[0139] The first skin 82 and the first interface film 800 obtained in step (b) can be cooled with the cooling device 98. This can be carried out before (and possibly during) step (c) of positioning the dimple network 86. For this purpose, the mold 90 comprising the first skin 82 and the first interface film 800 draped and stacked on this first skin 82, can be cooled with the cooling device 98. This makes it possible, for example, to avoid deforming and / or damaging the dimple network 86 when positioning it on the first interface film 800.

[0140] With reference to [Fig.9], step (c) can be carried out on the mold 90 comprising the first stack 820 and the first interface film 800 which are in particular cooled.

[0141] Step (c) can be performed manually by an operator.

[0142] Alternatively, step (c) can be carried out automatically. For this purpose, the installation 9 may further include a device for applying the dimple array 86 (not shown in the figures). This application device may be a gripper for positioning the dimple array 86 onto the first interface film 800.

[0143] Steps (a), (b) and (c), as illustrated in a non-limiting way in Figures 6 to 9, make it possible to produce the first skin 82 covering the network of alveoli 86, so as to form either the semi-open alveolar structure 80 of [Fig.2], or a part of the alveolar structure 80 of Figures 3 and 4.

[0144] Steps (d) and (e), as illustrated without limitation in Figures 10 and 11, are described below and enable the second skin 84 to be produced, also covering the honeycomb network 86, so as to form the honeycomb network 86 arranged between the first 82 and second 84 skins of the alveolar structure 80 of figures 3 and 4.

[0145] With reference to [Fig. 10] and optionally, step (d) can be carried out by the draping device 92. One or more second interface film(s) 802 can (or can) be deposited during this step (d).

[0146] During the draping of step (d), the mold 90 can be heated, for example, to a maximum temperature of approximately 300°C. This allows, in particular, for at least partial curing of the first stack 820.

[0147] In step (b), the heating device 96 can heat in particular up to a maximum temperature of about 500°C.

[0148] The hot air flow Fc from the mold 90 and / or the heating device 96 allows the first and second interface films 800, 802 to be heated, in particular by a radiant effect through the first stack 820, the first interface film 800 and the honeycomb network 86. This allows the formation of hook menisci 886a, 886b connecting the first and second interface films 800, 802 to the honeycomb network 86.

[0149] The hook menisci 886a, 886b can be formed between lateral walls of the alveolar cells of the alveolar network 86 and the interface films 800, 802.

[0150] The second 802 interface film can be deposited in strip form.

[0151] With reference to [Fig. 11] and optionally, step (e) can be carried out by the draping device 92 which makes it possible to carry out the second stacking 840 by draping the second layers of fibers on the second interface film 802.

[0152] During the draping of step (e), the mold 90 can be heated, in particular, up to a maximum temperature of approximately 300°C. This makes it possible, in particular, to maintain the curing consolidation of the first stack 820, the first interface film 800, and the second interface film 802 with the cell network 86.

[0153] In step (a), the heating device 96 can heat, in particular, up to a maximum temperature of approximately 500°C. This also makes it possible to consolidate, at least partially, the second stack 840 by firing, or entirely this second stack 840 (particularly in the case of consolidation by in situ firing).

[0154] Heating the first and second interface films 800, 802 by the hot air flow Fc from the heating device 96 and / or the mold 90 helps to strengthen the formation of the adhesion menisci 886a, 886b.

[0155] Step (e) can be carried out by draping the second layers of fibers of the second stack 820 in a different direction from that of the other second layers of fibers of this second stack 840. This makes it possible to form the second stack 840 with the second layers of crossed fibers in order in particular to ensure the transfer of forces in all directions.

[0156] Similar to the first stack 820, the second layers of fibers can be draped in different directions, the orientation angles of the second layers of fibers being chosen from the values ​​of 0°, 45°, -45° (or 135°) and 90°.

[0157] In step (e), the second layers of fibers of the second stack 840 can be deposited in the form of strips.

[0158] At least one of the steps (a), (b), (c), (d) and (e) includes a substep of compaction (ai5 b;, c;, d,, e;) of the fiber layers of the first and / or second stacks 820, 840 and of the first and / or second interface films 800, 802. This or these substeps of compaction (a;, b;, db e;) can (or can) be carried out with the compaction roller 94.

[0159] The substep (cO of compaction can be carried out by applying pressure to achieve compaction, preferably lighter than that achieved by the compaction roller 94.

[0160] The draping and compaction of at least one of the first and second stacks 820, 840 and of at least one of the first and second interface films 800, 802, can be carried out simultaneously.

[0161] Steps (a) and (e) can each include a substep of cooking (aü, en), or in other words of consolidation by cooking, of the first and second stacks 820, 840 to form respectively the first and second skins 82, 84.

[0162] According to a first embodiment, at least one of the sub-steps (aü, eü) of firing can (or can) be carried out during the draping of the first and / or second stacks 820, 840, as illustrated in Figures 7 and 11. In other words, the draping and firing of the first stack 820 and / or the second stack 840 can be carried out simultaneously. This substep or these substeps (aü, eü) can be carried out with the heating device 96. In the substep or substeps (aü, eü), the first and / or second stacks 820, 840 can be heated to carry out consolidation by baking, for example by the heating device 96. The heating device 96 can be self-heating and in this case allows the first 820 and / or second 840 stacks (and possibly the first interface film(s) 800, 802 deposited) to be consolidated (by baking) in situ.

[0163] According to a second embodiment, at least one of the substeps (aü, en) of firing (or in other words, of consolidation by firing) can be carried out after the draping of the first and / or second stacks 820, 840. This substep or these substeps (¾, eü) can be carried out with the external heating device. In this configuration, the first and / or second stacks 820, 840 can be heated to achieve consolidation (by cooking) known as in situ, especially when the external heating device is self-heating.

[0164] The method according to the invention may further include a perforation step (f) of one of the first and second skins 82, 84. This step (f) may be carried out after step (e). Step (f) may also include the perforation of one of the first and second interface films 800, 802. Step (f) enables the formation of the honeycomb structure 80 with an acoustic function.

[0165] Fig. 12 illustrates in a non-limiting way the perforation of the first skin 82 and the first interface film 800. In this configuration, the second skin 84 can be solid without perforations.

[0166] In an alternative not shown in the figures, the second skin 82 and the second interface film 802 can be perforated to form the honeycomb structure, either semi-open or closed. In this alternative, the first skin 82 can be solid without perforations.

Claims

Demands

1. A method for manufacturing a honeycomb structure (80) for a part (8), in particular for an aircraft turbomachine (10), said honeycomb structure (80) comprising a honeycomb array (86), a first skin (82) of composite material covering the honeycomb array (86), and optionally a second skin (84) of composite material and arranging the honeycomb array (86) between said first and second skins (82, 84), the method being characterized in that it comprises the steps of: (a) carrying out a first stacking (820) of several layers of fibers by draping so as to form the first skin (82), (b) depositing at least one first interface film (800) by draping onto the first skin (82), (c) positioning the honeycomb array (86) on the first interface film (800), (d) optionally depositing at least a second interface film (802) by draping over the honeycomb network (86),and (e) optionally perform a second stacking (840) of several layers of fibers by draping so as to form the second skin (84).

2. A manufacturing method according to claim 1, characterized in that at least one of the steps (a), (b), (c), (d) and (e) comprises a substep of compacting (ai5 b;, c;, d,, e;) the fiber layers of the first and / or second stacks (820, 840) and of the first and / or second interface films (800, 802), such as with a compacting roller (94) which is for example integrated into a draping device (92) for the substeps (ai5 b;, d,, e;), or with a pressurizing device for the substep (c;).

3. A manufacturing process according to claim 1 or 2, characterized in that steps (a) and (e) each comprise a substep of cooking (aü, eü) the first and second stacks (820, 840) to form respectively the first and second skins (82, 84).

4. A manufacturing method according to claims 2 and 3, characterized in that at least one of the cooking substeps (a^ en) is carried out during the draping of the first and / or second stacks (820, 840) with a heating device (96) integrated into the draping device (92), in which the first and / or second stacks (820, 840) are heated for example by a laser source, a plasma torch, an ultraviolet lamp or a flash lamp.

5. A method according to claim 3, characterized in that at least one of the substeps (aü, e;i) of cooking is carried out after draping the first and / or second stacks (820, 840) with an external heating device, in which the first and / or second stacks (820, 840) are heated for example in a heating device.

6. A manufacturing method according to any one of claims 1 to 5, characterized in that at least one of the steps (a) and (e) is carried out by draping at least one of the fiber layers of the first and / or second stacks (820, 840) in a direction different from that of the other fiber layers of the corresponding stack (820, 840).

7. A manufacturing method according to any one of claims 1 to 6, characterized in that prior to step (c), the first skin (82) and the first interface film (800) obtained in step (b) are cooled with a cooling device (98) for example of induction type, forced air type or with a heat transfer fluid.

8. A manufacturing method according to any one of claims 1 to 7, characterized in that at least one of the first and second skins (82, 84) comprises perforations (822), wherein the method further comprises a perforation step (f) of one of the first and second skins (82, 84) which is carried out after step (e).

9. A manufacturing method according to any one of claims 1 to 8, characterized in that the fiber layers of at least one of the first and second stacks (820, 840) comprise fibers pre-impregnated with a first thermoplastic material.

10. A manufacturing method according to any one of claims 1 to 9, characterized in that the cell network (86) is made of metal, such as aluminum, thermoplastic, paper or cardboard, in which the paper or cardboard is, for example, impregnated with a phenolic or aramid resin.

11. A manufacturing method according to any one of claims 1 to 10, characterized in that at least one of the first and second interface films (800, 802) comprises a second thermoplastic material.

12. A manufacturing process according to claims 10 and 11, characterized in that the second thermoplastic material has a

13. softening temperature lower than that of the first thermoplastic material. Honeycomb structure (80) for a part (8), in particular of an aircraft turbomachine (10), characterized in that this honeycomb structure (80) is produced by the manufacturing process according to any one of the preceding claims.

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