Method for manufacturing a rotationally symmetrical part made of composite material with insertion of an interlaminar antiadhesive

Abstract

The invention relates to a method for manufacturing a rotationally symmetrical part (100) made of a composite material for a gas turbine, the method comprising: winding a fibrous texture (140) over a plurality of superimposed turns on a mandrel in order to obtain a rotationally symmetrical fibrous preform (300), the preform extending in width in an axial direction, in thickness in a radial direction and in length in a circumferential direction; and densifying the fibrous preform with a matrix. During the winding of the fibrous texture, the method comprises inserting a strip of antiadhesive material between two adjacent turns of the fibrous texture, the strip of antiadhesive material extending in the circumferential direction along the interface between the adjacent turns and having a width of less than the width of the preform in the axial direction.

Description

Description Title of the invention: Method for manufacturing a part of revolution made of composite material with the insertion of an inter-ply anti-stick agent Technical Field

[0001] The present invention relates to the general field of manufacturing parts of revolution exposed to impacts and more particularly, but not exclusively, to gas turbine blower housings for aircraft engines. Previous technique

[0002] In a gas turbine aircraft engine, the fan casing performs several functions. It defines the air intake duct into the engine, supports an abradable material opposite the fan blade tips, supports a possible sound-absorbing structure for acoustic treatment at the engine inlet, and incorporates a retention shield. The retention shield acts as a debris trap, holding debris, such as ingested objects or fragments of damaged blades, propelled by centrifugal force, to prevent them from passing through the casing and reaching other parts of the aircraft.

[0003] Previously made of metallic material, housings, such as the blower housing, are now made of composite material, that is to say from a fibrous preform densified by an organic matrix, which makes it possible to produce parts with a lower overall mass than the same parts when made of metallic material while having at least equivalent if not superior mechanical resistance.

[0004] The fabrication of a blower housing from an organic matrix composite material is described in US patent 8,322,971. In the housing disclosed in US patent 8,322,971, the retention shield is formed by an increased thickness portion obtained from the housing's fibrous reinforcement, which has a progressively increasing thickness. The fibrous reinforcement is obtained by winding a 3D woven fibrous texture that has an increased thickness portion suitable for to form a retention shield. The housing thus obtained exhibits good mechanical properties at the level of its retention shield, both in terms of resistance to perforation (retention) and dynamic behavior.

[0005] However, the structural areas outside the retention zone are thinner and therefore offer less resistance to penetrating or non-penetrating impacts. Consequently, deformation of the outer face of the housing may occur when it is subjected to penetrating or non-penetrating forces.

[0006] Prior art solutions exist that aim to improve the resistance to deformation of the outer face of the housing. For example, document FR3109180 describes a housing with a metal strip on its outer surface. However, this solution results in a significant increase in the overall size and mass of the housing, particularly for a blower housing with a large diameter.

[0007] Furthermore, prior art solutions have the disadvantage of concentrating stresses on the outer face of the housing when it is subjected to penetrating or non-penetrating impacts. Indeed, the structure of prior art housings consists of a single piece or several layers bonded together. Thus, when the housing is subjected to a penetrating or non-penetrating impact, maximum stress or deformation is generated on the face opposite the force, namely the outer face of the housing. Description of the invention

[0008] The main purpose of the present invention is therefore to propose a solution for the manufacture of a blower housing which does not present the aforementioned disadvantages.

[0009] To this end, the invention proposes a method for manufacturing a part of revolution made of composite material for a gas turbine, comprising the following steps:

[0010] - the winding of a fibrous texture onto several superimposed turns on a mandrel in order to obtain a fibrous preform of the shape of revolution corresponding to that of the part of revolution to be manufactured, said preform extending in width along an axial direction, in thickness along a radial direction and in length along a circumferential direction,

[0011] - the densification of the fibrous preform by a matrix,

[0012] characterized in that, during the winding of the fibrous texture onto the mandrel, the process further comprises an interposition of at least one strip of an anti-stick material between at least two adjacent turns of the fibrous texture, said at least one strip of anti-stick material extending in the circumferential direction along the interface between said at least two adjacent turns and in that said at least one strip of anti-stick material has a width less than the width of the preform in the axial direction.

[0013] Thus, the manufacturing process produces a part of revolution with a delamination zone, which promotes stress distribution within the fiber reinforcement. This reduces deformation on the outer surface of the part while maintaining its overall structural integrity.

[0014] When the part is subjected to an impact, each of its layers will deform in isolation and dissipate some of the energy received before transmitting it to the adjacent layer.

[0015] Furthermore, the process makes it possible to obtain a part made of composite material with improved mechanical properties without increasing the overall mass.

[0016] The term "delamination" refers to a phenomenon which includes the at least partial dissociation of several layers in the fibrous reinforcement of the part.

[0017] According to a particular feature of the process of the invention, said at least one strip of non-stick material can extend over a width of between 5% and 25% of the width of said preform.

[0018] Such a width allows for a better compromise between good stress distribution and good overall structural integrity of the part.

[0019] This range of values ​​allows a good balance between reducing deformation on the external face of the part and preserving its structural integrity.

[0020] According to a particular feature of the process of the invention, the non-stick material can be chosen from polytetrafluoroethylene, paints, ceramics, alloys or a mixture thereof.

[0021] According to a particular feature of the process of the invention, the non-stick material may comprise polytetrafluoroethylene. Polytetrafluoroethylene has the advantage of very good chemical inertness, which prevents it from bonding to the matrix during densification and facilitates delamination. It also has the advantage of being flexible, which allows it to conform optimally to the surface of the fibrous texture on which it is placed.

[0022] The invention also relates to a composite material part of revolution for a gas turbine, comprising a fibrous reinforcement densified by a matrix, the fibrous reinforcement comprising a fibrous texture having a three-dimensional weave in the form of a band, said fibrous texture being wound on itself in several turns, said part extending in width along an axial direction, in thickness along a radial direction between a first and a second opposite face, and in length along a circumferential direction, characterized in that said reinforcement comprises a band of non-stick material between at least two adjacent turns of said fibrous texture, said at least one band of non-stick material extending in the circumferential direction along the interface between said at least two adjacent turns and in that said at least one band of non-stick material has a width less than the width of said reinforcement in the axial direction.

[0023] Thus, it is possible to distribute stresses within the fiber reinforcement when the part is subjected to penetrating or non-penetrating impacts. It is also possible to reduce the deformation generated on the outer face of the part while maintaining its structural integrity. Furthermore, the composite material part according to the invention offers the advantage of improved mechanical properties without increasing its overall mass.

[0024] According to a particular feature of the part of the invention, said at least one strip can extend over a width of between 10% and 25% of the width of said reinforcement.

[0025] According to a particular feature of the part of the invention, the non-stick material can be chosen from polytetrafluoroethylene, paints, ceramics, alloys or a mixture thereof. Brief description of the drawings

[0026] Other features and advantages of the present invention will become apparent from the description given below, with reference to the attached drawings which illustrate examples of embodiment without any limiting character.

[0027] [Fig. 1] Figure 1 schematically represents a turbomachine housing in one embodiment of the invention,

[0028] [Fig 2] Figure 2 is a cross-sectional view along plane II-II of the housing of Figure 1, showing the stacking of the superimposed towers of the housing according to one embodiment in the delamination zone of the housing,

[0029] [Fig. 3] Figure 3 is a perspective view showing the shaping of a fibrous texture and a strip of non-stick material intended to form the reinforcement of the blower housing of Figure 1,

[0030] [Fig. 4] Figure 4 is a schematic perspective view of a loom showing the weaving of a fibrous texture used for the formation of the fibrous reinforcement of the casing in Figure 1,

[0031] [Fig. 5] Figure 5 is a schematic view showing the simultaneous winding of the fibrous structure and the strip into a non-stick material of Figure 3,

[0032] [Fig. 6] Figure 6 is a cross-sectional view showing the profile of the fibrous preform obtained after winding the fibrous structure and the strip with an anti-stick material from Figures 3 and 5,

[0033] [Fig. 7] Figure 7 is a schematic view showing a tooling that allows the fibrous preform obtained after winding to be densified with a matrix. Description of the implementation methods

[0034] The invention applies generally to any gas turbine component of revolution made of composite material comprising a retention shield.

[0035] A manufacturing process for a part of revolution of the invention is described below, applied, according to a first example, to a blower housing for an aeronautical gas turbine engine.

[0036] Such an engine, as shown very schematically by figure 1, comprises, from upstream to downstream in the direction of the gas flow, a blower 1 arranged at the inlet of the engine, a compressor 2, a combustion chamber 3, a high-pressure turbine 4 and a low-pressure turbine 5.

[0037] The motor is housed inside a casing comprising several parts corresponding to different motor components. Thus, the blower 1 is surrounded by a blower casing 10 having a shape of revolution.

[0038] The fan housing 10 is made here of an organic matrix composite material, that is, from a fiber reinforcement, for example of carbon, glass, aramid, or ceramic, densified by a polymer matrix, for example epoxy, bismaleimide, or polyimide. The manufacture of such a housing is described in particular in US patent 8,322,971. The internal surface 11 of the housing defines the engine's air intake duct.

[0039] The housing 10 extends laterally along an axial direction D between its upstream and downstream ends (from left to right in Figure 2), which are fitted with external flanges 14, 15 to allow for its mounting and connection with other elements. The housing extends in thickness along a radial direction and in length along a circumferential direction. According to the invention, the housing 10 includes a delamination zone 12 (Figure 1).

[0040] The fibrous reinforcement is formed by winding a fibrous texture 140 onto a mandrel 200, produced by three-dimensional weaving, the mandrel having a profile corresponding to that of the housing to be produced (Figure 3).

[0041] The fibrous reinforcement of the housing 10 consists of a plurality of superimposed layers 141 to 144 of a fibrous texture 140 in the form of a strip having a three-dimensional or multi-layer weave, each layer 141 to 144 corresponding to one winding turn of the fibrous texture 140 (figure 2).

[0042] Furthermore, a strip of non-stick material 150 is interposed between two adjacent layers of the fibrous texture, the strip of non-stick material 150 having a width li 50 less than the width li 40 of the fibrous texture 140 (figure 3) and delimiting the delamination zone of the housing 10.

[0043] In the example shown in Figure 2, layers 151 to 153 of a non-stick material 150 are interposed between the superimposed layers 141 to 144 of the fibrous texture 140, each layer 151 to 153 corresponding to one winding of the non-stick material 150. Generally, the non-stick material 150 used to form a delaminated portion can be interposed between two or more superimposed layers of fibrous texture 140, each corresponding to one winding of said fibrous texture 140. In Figure 2, the thickness of layers 151 to 153 has been intentionally exaggerated to facilitate understanding. The interposition of the non-stick material 150 between two or more layers of fibrous texture 140 does not necessarily create an increased thickness in the fibrous texture 140. in the final play.

[0044] In prior art solutions, the structure of the part of revolution is either a single piece or composed of several layers of fibrous material bonded together. Thus, when the housing is subjected to penetrating or non-penetrating forces, maximum stress and deformation are generated on the outer face opposite the force, i.e., the outer surface of the housing. By adding a non-stick material strip, it is possible to give the part specific mechanical properties. Indeed, the interposition of the non-stick material strip creates a multi-layered structure. Locally decoupled, delamination occurs within the part's structure. When the part is subjected to penetrating or non-penetrating forces, each portion of the delaminated layer will deform and dissipate energy before transmitting the stress to the adjacent layer. The stress is thus distributed throughout the casing's layers. It is therefore possible to reduce the deformation on the outer face while maintaining the overall structural integrity of the part.

[0045] Furthermore, the addition of the non-stick material strip facilitates delamination of adjacent axial portions. The width of the fibrous texture covered by the non-stick material strip constitutes a delamination initiation zone. Delamination propagates easily and rapidly from this initiation zone to the adjacent axial portions not covered by the non-stick material strip. Thus, a portion of the energy received during the impact is dissipated by each layer of the part.

[0046] The strip, made of a non-stick material, can extend over a width of between 5% and 25% of the width of said fibrous reinforcement.

[0047] The strip made of a non-stick material can extend over a width that corresponds to 10% of the width of said fibrous reinforcement.

[0048] This allows for the best compromise between good stress distribution and good overall structural integrity of the part.

[0049] The non-stick material can be chosen from polytetrafluoroethylene, paints, ceramics, alloys.

[0050] The thickness of the strip in a non-stick material can be less than or equal to 0.9 mm (to be confirmed).

[0051] The non-stick material may include polytetrafluoroethylene (PTFE). PTFE has the advantage of excellent chemical inertness, which prevents it from bonding to the matrix during densification and facilitates delamination. It is also flexible, allowing it to conform optimally to the surface of the fibrous material on which it is placed.

[0052] We now describe a manufacturing process for the blower housing 10.

[0053] As illustrated in Figure 4, a fibrous texture 140 is produced in a known manner by weaving using a jacquard type loom 100 on which a bundle of warp yarns or strands 20 has been arranged in a plurality of layers, the warp yarns being linked by weft yarns or strands 30. The fibrous texture 140 is produced by three-dimensional weaving.

[0054] The term "three-dimensional weaving" or "3D weaving" refers to a weaving method in which at least some of the weft threads interlock with warp threads across multiple layers of warp threads, or vice versa. An example of three-dimensional weaving is interlocking. Interlocking weaving is a weave structure in which each layer of warp threads interlocks with multiple layers of weft threads, with all the threads in the same warp column moving in the same direction within the plane of the weave.

[0055] The creation of the fibrous texture by 3D weaving makes it possible to obtain a bond between the layers, thus having good mechanical strength of the fibrous structure and the part made of composite material obtained, in a single textile operation.

[0056] As illustrated in Figure 4, the fibrous texture 140 has a band-like shape extending lengthwise in an X direction corresponding to the direction of travel of the warp yarns or strands 20 and widthwise or transversely in a Y direction corresponding to the direction of the weft yarns or strands 30. As explained below, the fibrous reinforcement of the part of revolution, here the housing 10, is formed by the fibrous texture 140, which is shaped by winding it upon itself (Figure 3). Consequently, in the fibrous reinforcement of the final part, the warp yarns or strands extend along the circumferential direction D c(Figure 1) while the weft yarns or strands extend along the axial direction D A (Figure 1).

[0057] The fibrous texture 140 can be woven from fiber yarns of carbon type, ceramic such as silicon carbide, glass, or aramid.

[0058] As illustrated in Figure 3, a fibrous preform is formed by winding the fibrous texture 140, produced by three-dimensional weaving, onto a mandrel 200. The mandrel has a profile corresponding to that of the housing to be produced. According to the invention, a strip of non-stick material 150 is wound simultaneously with the fibrous texture 140. The strip 150 is positioned above the first layer 141 of the texture 140 wound onto the mandrel 200 so as to interpose a layer of the narrower non-stick material 150 between two adjacent layers of the wider fibrous texture, corresponding to two turns of the fibrous texture 140. The strip 150 is positioned at a location on the fibrous texture 140 corresponding to the axial delamination zone to be formed in the part.

[0059] According to a particular feature of the invention, the width li 40may correspond to a winding turn of the fibrous texture 140.

[0060] The mandrel 200 has an external surface 201 whose profile corresponds to the internal surface of the housing to be produced. By winding onto the mandrel 200, the fibrous texture 140 conforms to its profile. The mandrel 200 also includes two flanges 220 and 230 to form portions of the fibrous preform corresponding to the flanges 14 and 15 of the housing 10 (Figure 3).

[0061] During the formation of the fibrous preform by winding, the fibrous texture 140 and the strip in a non-stick material 150 are called from drums 60 and 70 respectively on which they are stored as illustrated in Figure 5.

[0062] Figure 6 shows a cross-sectional view of the fibrous preform 300 obtained after winding the fibrous texture 140 and the non-stick material strip 150 in several layers onto the mandrel 200. In the example described here, the preform 300 comprises four layers 141 to 144 of fibrous texture 140 and three layers 151 to 153 of the non-stick material strip 150, interposed respectively between the adjacent layers 141 and 142, 142 and 143, and 143 and 144. The thickness of the layers 151 to 153 in Figure 6 has been intentionally exaggerated for clarity. The interposition of the non-stick material strip 150, between two or more layers of fibrous texture 140, does not necessarily generate an overthickness in the fibrous texture 140 or in the final part.

[0063] The preform 300 can comprise 4 layers 141 to 144 of fibrous texture 140 and a layer of strip in a non-stick material 150.

[0064] A fibrous preform 300 is obtained with a delamination zone formed by the interposition of layers 151 to 153 of the strip 150 between the superimposed layers 141 to 144 of the fibrous texture 140.

[0065] The next step is to densify the fibrous preform 300 using a matrix.

[0066] The densification of the fibrous preform consists of filling the porosity of the preform, in all or part of its volume, with the material constituting the matrix.

[0067] The matrix can be obtained in a manner known per se following the liquid process.

[0068] The liquid process involves impregnating the preform with a liquid composition containing an organic precursor of the matrix material. The organic precursor is usually in the form of a polymer, such as a resin, possibly diluted in a solvent. The fibrous preform is placed in a mold that can be sealed tightly with a cavity shaped like the final molded part. As illustrated in Figure 7, the fibrous preform 300 is positioned between a plurality of sectors 240 forming a counter-mold and the mandrel 200 forming a support, these elements having, respectively, the external and internal shapes of the housing to be produced. The liquid matrix precursor, for example, a resin, is then injected into the entire cavity to impregnate the entire fibrous portion of the preform.

[0069] The transformation of the precursor into an organic matrix, namely its polymerization, is carried out by heat treatment, generally by heating the mold, after the removal of any solvent and crosslinking of the polymer. The preform remains in the mold, which has a shape corresponding to that of the part to be produced. The organic matrix can be obtained, in particular, by... starting from epoxy resins, such as, for example, a commercially available high-performance epoxy resin, or from liquid precursors of carbon or ceramic matrices.

[0070] According to one aspect of the invention, the densification of the fibrous preform can be achieved by the well-known resin transfer molding (RTM) process. In accordance with the RTM process, the fibrous preform is placed in a mold having the shape of the housing to be produced. A thermosetting resin is injected into the internal space defined between the mandrel 200 and the counter-molds 240, which includes the fibrous preform. A pressure gradient is generally established in this internal space between the point where the resin is injected and the resin discharge ports in order to control and optimize the impregnation of the preform by the resin.

[0071] The resin used can be, for example, an epoxy resin. Resins suitable for RTM processes are well-known. They preferably have a low viscosity to facilitate their injection into the fibers. The choice of temperature class and / or the chemical nature of the resin is determined according to the thermomechanical stresses to which the part will be subjected. Once the resin has been injected throughout the reinforcement, it is cured by heat treatment according to the RTM process.

[0072] After injection and polymerization, the part is demolded. Finally, the part is trimmed to remove excess resin and the chamfers are machined to obtain the housing 10 illustrated in figure 1.

Claims

Demands

1. A method for manufacturing a part of revolution (100) made of composite material for a gas turbine, comprising the following steps: - the winding of a fibrous texture (140) onto several superimposed turns (141, 142, 143, 144) on a mandrel (200) in order to obtain a fibrous preform (300) of a shape of revolution corresponding to that of the part of revolution to be manufactured, said preform extending in width along an axial direction (D A ), in thickness along a radial direction (D R ) and in length along a circumferential direction (D c ) , - the densification of the fibrous preform (300) by a matrix, characterized in that, during the winding of the fibrous texture (140) onto the mandrel (200), the process further comprises an interposition of at least one strip of a non-stick material (150) between at least two adjacent turns of the fibrous texture (140), said at least one strip of non-stick material (150) extending in the circumferential direction (De) along the interface between said at least two adjacent turns, and in that said at least one strip of non-stick material has a width less than (li 50 ) to the width of the preform (li4o) along the axial direction (D A ).

2. Method according to claim 1, wherein said at least one strip extends over a width between 5% and 25% of the width of said preform (300).

3. A method according to any one of claims 1 or 2, wherein the non-stick material is selected from polytetrafluoroethylene, paints, ceramics, alloys or a mixture thereof.

4. A composite material part of revolution for a gas turbine, comprising a matrix-densified fibrous reinforcement, the fibrous reinforcement comprising a fibrous texture having a three-dimensional, band-like weave, said fibrous texture (140) being wound upon itself in several turns, said part extending in width along an axial direction (D A ), in thickness along a radial direction (DR) between a first and a second opposite face, and in length along a circumferential direction (D c ), characterized in that said reinforcement includes a strip of non-stick material (150) between at least two adjacent turns of said fibrous texture, said at least one strip of non-stick material (150) extending in the circumferential direction (De) along the interface between said at least two adjacent turns and in that said at least one strip of non-stick material has a width less (1150) than the width of said reinforcement (1140) in the axial direction (D).

5. Part according to claim 4, wherein said at least one strip extends over a width between 5% and 25% of the width of said reinforcement.

6. Part according to any one of claims 4 or 5, wherein the non-stick material is selected from polytetrafluoroethylene, paints, ceramics, alloys or a mixture thereof.

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