Method for manufacturing a composite part with an integrated seal and part made of composite material obtained by such a method

Abstract

The invention relates to a method (100) for manufacturing a part (1) made of composite material with fibrous reinforcement densified by a matrix for a turbomachine, the part being equipped with at least one integrated seal (2) projecting from a surface of the part, the method comprising the following steps: - providing a preform (9) forming the fibrous reinforcement comprising non-organic fibers, - providing at least one seal, - placing the preform in a first cavity (51) of a mold (50), - placing a portion of the seal in a cavity (53) of the mold (50) in a form-fitting manner, the seal being made of a material different from that of the part made of composite material, - closing the mold (50) in order to press the seal against a surface of the preform, - applying heat and pressure to the preform and the seal in order to obtain the part made of composite material with the integrated seal.

Description

Description TITLE: METHOD FOR MANUFACTURED A COMPOSITE PART WITH AN INTEGRATED JOINT AND A COMPOSITE PART OBTAINED BY SUCH A METHOD Technical field of the invention

[0001] The present invention relates to the aeronautical field. It relates in particular to a method for manufacturing a part made of composite material with fiber reinforcement densified by a matrix. Technological background

[0002] Prior art includes documents DE102015201346A1, W02020 / 008486A1 and DE102013009931.

[0003] Figure 1 shows an example of an aircraft turbomachine 01 comprising a cowling 02 centered on the longitudinal axis X of the turbomachine 01 and mounted downstream of a fan or propeller. This cowling 02 is also radially mounted around an annular ferrule 03. This cowling 02 is made, in a known manner, from a fiber-reinforced composite material densified in a matrix. Seals 04 are attached to an external surface 05 of the composite cowling 02 to fill gaps and / or prevent fluid leaks. These seals, generally flexible to allow for deformation, are added and fixed after the composite cowling 02 has been manufactured.

[0004] Such a configuration represents a cost and may present a risk of reduced quality.

[0005] There is a need to resolve all or part of the aforementioned drawbacks. Summary of the invention

[0006] The objective of the present invention is to provide a simple and economical solution for easily integrating a flexible element into a composite material.

[0007] We achieve this objective in accordance with the invention through a method of manufacturing a part made of fiber-reinforced composite material densified by a die for a turbomachine, equipped with at least one seal which is integrated and which protrudes from a surface of the part, the process comprising the following steps: - supply of a preform forming the fibrous reinforcement comprising non-organic fibers, - supply of at least one seal, - placement of the preform in the first cavity of a mold, - placement of at least a portion of the seal in a cavity of the mold by complementary shape, the seal being made of a material different from the composite material of the part made of composite material, - closing the mold so as to apply the seal to a surface of the preform, and - thermocompression of the preform and the seal to obtain the part in composite material with the integrated seal.

[0008] Thus, this solution achieves the aforementioned objective. In particular, the composite part includes at least one integrated seal embedded in the fiber reinforcement and matrix during the single thermocompression step. Therefore, it is no longer necessary to install the seal after manufacturing the composite part, resulting in time savings and reduced manufacturing costs. Furthermore, incorporating the seal during the thermocompression step improves the control of positioning tolerances on the composite part(s). Positioning tolerances are reduced, as is the number of additional components, since the seal(s) are already fixed.

[0009] The process also includes one or more of the following steps and / or features, taken alone or in combination where technically feasible: - the seal includes at least one functional portion intended to be installed in the cavity and enabling sealing, and at least one base intended to be integrated into the densified preform. - the fibrous reinforcement includes fibers selected from the group including Kevlar fibers, glass fibers, carbon fibers. - the process includes a step of injecting a polymeric matrix into the preform. - the preform fibers are pre-impregnated. - the matrix is ​​chosen from thermosets, thermoplastics and vitrimers. - the matrix comprises a predetermined charge of particles. - the seal is made of an elastomer, a rubber or a silicone. - the functional portion includes a circular, V-shaped, arrow-shaped, lip-shaped with an inclination, or triangular section. - the base has a cross-section of rectilinear, arrow-shaped, triangular or trapezoidal shape. - the base has holes. - the joint includes a sealing gasket. - the mold closing step includes a sub-step of moving a part of the mold so as to apply the seal to the preform. - the mold comprises a first part and a second part, each first part and second part comprising a cavity intended to receive the preform.

[0010] The invention also relates to a composite material part obtained by the manufacturing process as above, the composite material part comprising the fibrous reinforcement densified by the matrix and at least one thermo-compressed joint with the fibrous reinforcement and the matrix, the base being configured so as to be extracted and replaced.

[0011] The invention further relates to a mold for molding a part in composite material with fiber reinforcement densified by a matrix and equipped with at least one seal for a turbomachine, the mold comprising a first part having a first impression and a second part having a second impression forming a space intended to receive a preform forming the fiber reinforcement and at least one cavity having a complementary shape with a portion of the seal. Brief description of the figures

[0012] The invention will be better understood, and other objects, details, features, and advantages thereof will become more apparent upon reading the detailed explanatory description that follows, of embodiments of the invention given in These are purely illustrative and non-limiting examples, with reference to the attached schematic drawings in which: - Figure 1 illustrates an axial cross-section of an example of a turbomachine according to the prior art; - Figure 2 schematically represents in axial section an example of assembly between two parts of a turbomachine, one of the parts being made of a composite material and being equipped with an integrated flexible element according to the invention; - Figure 3 is a flowchart of a manufacturing process for a part made of fiber-reinforced composite material densified by a matrix; - Figure 4 is a cross-sectional view of a manufacturing step of a part made of composite material intended to be installed in a turbomachine according to the invention; - Figure 5 is a cross-sectional view of another manufacturing step of a part made of composite material intended to be installed in a turbomachine according to the invention; - Figure 6 is a cross-sectional view of another manufacturing step of a part made of composite material intended to be installed in a turbomachine according to the invention; - Figure 7 is a cross-sectional view of an embodiment of a flexible element integrated into a part made of composite material according to the invention; - Figure 8 is a cross-sectional view of another embodiment of an element integrated into a part made of composite material according to the invention; - Figure 9 is a cross-sectional view of another embodiment of an element integrated into a part made of composite material according to the invention; - Figure 10 is a cross-sectional view of another embodiment of an element integrated into a part made of composite material according to the invention; - Figure 11 is a cross-sectional view of another embodiment of an element integrated into a part made of composite material according to the invention; - Figure 12 is a cross-sectional view of another embodiment of an element integrated into a part made of composite material according to the invention; - Figure 13 is a cross-sectional view of another embodiment of an element integrated into a part made of composite material according to the invention. - Figure 14 is a cross-sectional view of another embodiment of at least one element integrated into a part made of composite material according to the invention. Detailed description of the invention

[0013] Figure 1 has been described above.

[0014] In this description, identical or substantially identical elements and / or elements with the same functions are represented by the same numerical references.

[0015] Figure 2 shows a composite part 1 equipped with a flexible element. By "flexible element," we mean an element with a lower hardness than the composite material of part 1. In the following description, the flexible element advantageously includes a seal 2, which is not limited to this type. The seal 2 shown in Figure 2 includes a sealing gasket, but the gasket could be another type.

[0016] The sealing gasket 2 is located on the surface or around the perimeter of the composite material part. Several sealing gaskets may be located on the surface or around the perimeter. In the case of multiple sealing gaskets, they are arranged regularly around the surface or perimeter.

[0017] Advantageously, part 1 made of composite material is produced from a densified fibrous reinforcement in a matrix.

[0018] Advantageously, part 1, made of composite material, is intended to be mounted in an aircraft turbomachine (not shown). The aircraft comprises, for example, a fuselage and two wings extending on either side of the fuselage relative to the fuselage axis. Each wing can carry at least one turbomachine.

[0019] The turbomachine generally comprises, from upstream to downstream, a compressor assembly, a combustion chamber and a turbine assembly which preferably forms a gas generator.

[0020] Turbomachine 1 can be a turbojet or a turboprop.

[0021] The turbomachine 1 may include at least one rotating element, which may be a propeller or a fan. The propeller may be shrouded or unshrouded. The propeller is advantageously mounted upstream of the compressor assembly.

[0022] The composite material part 1 illustrated in Figure 2 is, by way of example, a turbomachine hood which is preferably mounted downstream of the propeller.

[0023] The hood is advantageously annular and centered on a longitudinal axis X, which is here the axis of rotation of the turbomachine rotors. As shown, the hood is fixed to a ferrule 3, which is advantageously annular and centered on the longitudinal axis X. The fastening is advantageously achieved by means of fasteners 4. The fasteners 4 can be threaded elements such as screws and bolts. The hood is equipped with a seal 2, which is integrated into the composite material and extends radially from an internal surface 5 of the hood. The seal 2 is advantageously arranged radially between the hood and the ferrule 3 and bears against the ferrule 3. The seal 2 is compressed when the hood is tensioned by the fasteners 4 on the ferrule 3, thus ensuring a seal.

[0024] Alternatively, the sealing gasket 2 is mounted on a radially external surface 6 of the hood, and optionally the ferrule 3 is mounted radially outside the hood. According to yet another alternative, the sealing gasket 2 could extend from several surfaces of the composite material part, in this case the hood. According to yet another alternative, one or more sealing gaskets could extend from a side face or edge of the composite material part.

[0025] In this embodiment, the ferrule 3 includes a recess 7 which is formed in a radially external surface 8 of the ferrule 3. At least a portion of the sealing gasket is received in the recess 7.

[0026] Advantageously, the fibrous reinforcement of part 1 comprises inorganic fibers. For example, the fibers include mineral fibers, metallic fibers, thermoplastic polymers, thermosetting polymers, or a mixture of these fibers. The fibers of the fibrous reinforcement are selected, for example, from the group including Kevlar® fibers, glass fibers, and carbon fibers. Generally, these fibers have a fiber count between 100 tex and 2500 tex. The fibers can be long, continuous fibers arranged in unidirectional (UD) webs or two-dimensional (2D) or three-dimensional (3D) weaves. stacked. The fibers may also be partially or entirely composed of long, discontinuous fibers in the form of mats, or mattresses of fibrous pieces or pieces of fabric. The fibers may also be short fibers.

[0027] The matrix or resin allows for the densification and bonding of the fibrous reinforcement to obtain the final rigid composite part. The terms "matrices" and "resins" are used interchangeably in this description. The matrix can be selected from thermosetting, thermoplastic, and vitrimer polymers. Examples of thermoplastic resins include polyamide, polyetheretherketone, polyetherketoneketone, poly(phenylene sulfide), and polyaryletherketone. Thermosetting resins include, for example, epoxide and polyimide.

[0028] In one embodiment, the matrix comprises particle fillers designed to enhance the mechanical properties of the composite part, such as its strength. The particles can be microscopic, submicroscopic, or nanoscopic. For example, the matrix can be filled with glass microbeads, hollow microspheres, glass, thermoplastic nanonodules, carbon nanotubes, or graphene particles. The particles can have various shapes, such as spherical, filamentous, etc.

[0029] Following an example of embodiment, the fibers are advantageously pre-impregnated with the polymer matrix.

[0030] The sealing gasket 2 is advantageously made from a material different from the composite part material. The material of the sealing gasket 2 can include an elastomer, a rubber, a silicone, etc. The sealing gasket material has a resistance to a predetermined temperature higher than the thermocompression temperature of the composite material. For example, for a panel made of epoxy matrix composite cured at 180°C, the sealing gasket 2 can be made from rubber, silicones, or fluorocarbons.

[0031] Advantageously, the sealing gasket 2 has a hardness ranging from 10 Shore I to 200 Shore B (measured according to standard J IS K6253). Conversely, the hardness of the composite material can range from 20 to 80 Barcol. The hardness of the sealing gasket 2, or its flexibility, allows it to perform the sealing function with another component, in this case, the ferrule 3. The gasket may also incorporate fibers such as glass, polyester, polyethylene, Kevlar®, etc., in its internal structure, giving it higher tensile strength while maintaining flexibility.

[0032] We will now describe in detail the manufacturing process 100 for such a part made of composite material. This process is shown in Figure 3.

[0033] The process 100 includes a step 110 of supplying a preform 9 that forms the fibrous reinforcement. The preform 9 is formed, for example, by 2D or 3D weaving. Alternatively, the preform 9 is obtained by draping several layers of fibers.

[0034] Process 100 includes a step 120 of supplying at least one seal 2. In the remainder of the process description, seal 2 includes, but is not limited to, a sealing gasket. Seal 2 is produced, for example, by casting, injection molding, or even extrusion. Its construction may involve bonding operations (butt joining between ends to form an annular or closed seal).

[0035] The process 100 includes a step 130 of placing a preform 9 in a mold 50. Advantageously, the preform 9 forms the fibrous reinforcement.

[0036] According to one embodiment, the mold 50 comprises a first part 50a and a second part 50b. The first part 50a of the mold 50 advantageously comprises the first cavity 51 intended to form a first (internal) face of the preform 9. The second part 50b of the mold 50 advantageously comprises a second cavity 52 which opens onto an internal surface of the second part 50b. Advantageously, the preform 9 can be installed in the first cavity 51 or alternatively in the second cavity 52 of the mold.

[0037] In this example, the second cavity 52 is oriented towards the preform 9 when the latter is installed in the first cavity 51. When the preform 9 is installed in the second cavity 52, the first cavity is advantageously positioned with respect to the preform 9. The second cavity 52 has a complementary shape with a second (external) surface of the preform 9. The first cavity 51 and the second cavity 52 form a receiving space for the preform 9.

[0038] Advantageously, the second part 50b of the mold 50 is movable relative to the first part 50a, for example between an open position and a closed position. The first part 50a moves in a non-limiting manner along at least one translation.

[0039] In one embodiment, the mold 50 comprises at least one cavity 53 configured to receive at least part of a sealing gasket 2. The mold 50 may comprise several cavities 53 spaced apart. Each cavity 53 advantageously opens into the second impression 52 of the second part 50b of the mold 50. Each cavity 53 has a complementary shape to at least part of the sealing gasket 2. Optionally, each cavity 53 is machined in the second part 50b of the mold 50. Alternatively, each cavity 53 is machined in the first part 50a of the mold. Each cavity 53 advantageously opens into the first impression 51. According to yet another alternative, cavities are machined in the first part and the second part 50b of the mold 50, and preferably on either side of the separation limit of the first and second parts.

[0040] According to another embodiment, the cavity or each cavity 53 is obtained simultaneously during the manufacture of at least one of the first and second parts 50a, 50b of the mold 50 or of each first and second part 50a, 50b of the mold 50. The first part 50a or the second part 50b of the mold 50 can be made by any technique known in the prior art, for example, casting, machining, additive manufacturing, forging, etc.

[0041] According to another embodiment, each first part and / or second part having one or more cavities 53, comprises two sub-parts which are assembled together to form the first part 50a or the second part 50b.

[0042] According to one embodiment, the mold includes at least one insert provided with the sealing gasket 2. The insert is fixed on the first part and / or the second part 50b of the mold 50.

[0043] The process 100 further includes a step 140 of placing at least a portion of the seal into a cavity 53 of the mold by complementary shape. Advantageously, but not exclusively, at least a portion of each seal 2 is placed by complementary shape of at least a portion into the cavity 53 of the mold, and preferably, into the cavity 53 formed in the second part 50b of the mold 50. In Figure 4, the cavity 53 has, but is not limited to, a circular cross-section. The cross-section or shape of the cavity 53 may, of course, be different.

[0044] The sealing gasket 2 advantageously, but not exclusively, comprises at least one functional portion 2a and at least one base 2b. In the example shown in Figure 4, the functional portion 2a has a circular cross-section and the base 2b has a straight cross-section parallel to the radially internal surface of the part 1. The functional portion 2a is installed by complementary shape within the circular cavity 53. In other words, the cavity 53 has the same shape or cross-section as the functional portion 2a.

[0045] Optionally, each cavity 53 may have dimensions locally larger than the volume required to house the functional portion 2a. This may allow the passage of external tools. Optionally, each cavity 53 may have dimensions, at least locally, very slightly (on the order of 3%) smaller than the nominal volume of the functional portion 2a, so as to allow the sealing gasket 2 to be pinched at these points and thus held with the tooling portion in which each cavity 53 is formed until the molding of the part 1.

[0046] The base 2b is advantageously integrated into the preform 9. The sealing gasket 2, in this non-limiting example, has a shape of b or p. Of course, the sealing gasket 2 can have any shape. The hardness of the sealing gasket 2 facilitates the preferential insertion of the functional portion 2a into the cavity 53 of the mold 50. Furthermore, the hardness of the sealing gasket 2 ensures its retention within the cavity 53.

[0047] The process advantageously includes a closing step 150 of the mold 50 so as to apply the sealing gasket 2 to a surface of the preform 9. Advantageously, but not limitingly, the closing step 150 includes a substep of moving a portion of the mold, preferably the second portion 50b of the mold 50, so as to apply the sealing gasket 2 to the preform 9. The movement substep is shown in Figure 4. Advantageously, the movement is carried out in a vertical direction towards the preform 9.

[0048] The process 100 advantageously comprises a thermocompression step 160 of the preform 9 and the sealing gasket 2. During the thermocompression step, shown in Figure 5, a predetermined heat and a predetermined force are applied to the mold 50. For example, a temperature of 100°C to 180°C can be applied to the mold 50, enabling the consolidation of the composite material comprising the preform 9. For example, a force of 50,000 N to 5,000,000 N can be applied to the first and second parts 50a, 50b of the mold 50 over a surface area of ​​1 m². 2 capable of producing a pressure of 0.5 MPa to 50 MPa on preform 9.

[0049] At the end of the relative movement phase between the tooling parts, the mold 50 is advantageously in the closed position, meaning that the peripheral contours of the first and second parts 50a and 50b are pressing against each other at their parting line (or separation plane). This allows the preform 9 to be densified and the sealing gasket 2 to be fixed to the preform 9 in a single step. The creep of the preform 9 during the closing of the mold 50 allows at least a portion of the sealing gasket 2 to be embedded in the preform 9. The pressurization of the sealing gasket 2 also advantageously allows Seal cavity 53 of mold 50. The resin cannot enter cavity 53.

[0050] Prior to the thermocompression step 160, the process 100 optionally includes a step of injecting a polymeric matrix into the preform 9, which is installed in the second cavity 52 of the second part 50b of the mold 50. The matrix is ​​injected in liquid form to impregnate and bind the fibers and the sealing gasket 2 together until the matrix hardens.

[0051] Preferably, the fibers are pre-impregnated. The preform 9 with the pre-impregnated fibers is compressed when the mold 50 is closed.

[0052] The process 100 advantageously includes an opening step 170 of the mold 50, which is shown in Figure 6. During this opening step 170, the second part 50b of the mold 50 advantageously moves vertically in the opposite direction to the closing step 150. The sealing gasket 2, which is embedded in the composite part, automatically disengages from the cavity 53 of the mold 50.

[0053] As described previously, the sealing gasket 2 can have any shape, as illustrated in Figures 7 to 14. Advantageously, but not exclusively, the functional portion 2a of the sealing gasket 2 provides a seal with an adjacent part. The shape of the functional portion 2a can be adapted as required. The functional portion 2a can advantageously be cylindrical, X-shaped, V-shaped, a double lip, etc.

[0054] Advantageously, but not exclusively, the base 2b allows for anchoring or embedding in the preform 9. The shape of the base 2b is also dependent on the need and allows for its interchangeability. In particular, the shape of the base 2b may allow for its removal and replacement with a new sealing gasket 2. The base 2b may, for example, have a trapezoidal, rectilinear, etc., cross-section.

[0055] Replacing a new seal 2 could be accomplished by removing the seal from cavity 53 and inserting a new seal into cavity 53 in an inverted trapezoidal shape. This insertion is possible due to the seal's significant deformation capacity in this area.

[0056] In Figure 7, the functional portion 2a has a circular cross-section. The functional portion 2a of the sealing gasket 2 protrudes from the densified preform 9. The base 2b has a roughly trapezoidal cross-section. The base 2b is integrated into the densified preform 9.

[0057] In Figure 8, the functional portion 2a is straight and inclined relative to the external surface of the preform 9 (or the composite part). The angle of the functional portion can be between 30° and 60°. The functional portion 2a is shaped, for example, like a lip. The base 2b is straight. The direction of the base is advantageously parallel to the external surface of the preform 9.

[0058] In Figure 9, the functional portion 2a has a V-shaped section that extends outward from the surface of the preform 9. The base 2b has a trapezoidal cross-section.

[0059] In Figure 10, the functional portion 2a has a circular cross-section. The base 2b has an arrow-shaped, harpoon-shaped, or triangular cross-section. The arrow is optionally oriented in a direction opposite to the surface of the preform 9.

[0060] In Figures 11 and 12, the functional portion 2a has a circular cross-section. The base 2b has an arrow-shaped, harpoon-shaped, or triangular cross-section. The arrow is optionally oriented in a direction opposite to the surface of the preform 9. In this embodiment, the sealing gasket 2 has through holes 10 on both sides of the base 2b. The holes 10 are preferably aligned in the same direction and transversely to the direction of the base 2b. During pressurization in the thermocompression step, the holes 10 will be filled by the matrix.

[0061] In Figure 13, the sealing gasket 2 is positioned on a lateral surface of the preform 9. The functional portion 2a has a triangular cross-section, and the base 2b is straight. The direction of the base 2b is parallel to the external surface of the preform 9.

[0062] In Figure 14, the sealing gasket 2 comprises several functional portions 2a and several bases 2b. Advantageously, the bases 2b are interconnected. A functional portion 2a' extends from the outer surface of the preform 9, and a functional portion 2a” projects from the lateral surface of the preform 9. The functional portion 2a' has a circular cross-section. The functional portion 2a” has a triangular cross-section. A base 2b extends into the preform and transversely across the external surface of the preform 9. Straight portions connect the functional portions 2a', 2a” and the base 2b. The straight portions cover at least a portion of the external and lateral surfaces of the preform 9.

[0063] Of course, other combinations of functional portion shapes 2a and bases 2b can be considered.

[0064] In this way, with such a manufacturing process, we obtain a part made of composite material with one or more 2 flexible material seals integrated into the monolithic composite material part.

Claims

Demands [1] Method of manufacturing (100) a part (1) of matrix-densified fiber-reinforced composite material for a turbomachine, equipped with at least one seal (2) which is integrated and which projects from a surface of the part, the process comprising the following steps: - supply (110) of a preform (9) forming the fibrous reinforcement comprising non-organic fibers, - supply (120) of at least one seal (2), - placement (130) of the preform (9) in a first cavity (51) of a mold (50), - placement (140) of at least a portion of the seal (2) in a cavity (53) of the mold (50) by complementary shape, the seal (2) being made of a material different from the composite material of the part made of composite material, - closing (150) of the mold (50) so as to apply the seal (2) to a surface of the preform (9), - thermocompression (160) of the preform (9) and of the seal (2) so as to obtain the part in composite material with the seal (2) integrated. [2] Manufacturing method (100) according to the preceding claim, characterized in that the seal (2) comprises at least one functional portion (2a, 2a', 2a”) intended to be installed in the cavity (53) and enabling sealing, and at least one base (2b) intended to be integrated into the densified preform (9). [3] Manufacturing method (100) according to claim 1 or 2, characterized in that the fibrous reinforcement comprises fibers selected from the group comprising Kevlar® fibers, glass fibers, carbon fibers. [4] Manufacturing method (100) according to any one of claims 1 to 3, characterized in that it comprises a step of injecting a polymeric matrix into the preform (9). [5] Manufacturing method (100) according to any one of claims 1 to 4, characterized in that the preform fibers (9) are pre-impregnated. [6] Manufacturing method (100) according to any one of claims 1 to 5, characterized in that the matrix is ​​selected from thermosets, thermoplastics and vitrimers. [7] Manufacturing method (100) according to any one of the preceding claims, characterized in that the matrix comprises a predetermined charge of particles. [8] Manufacturing method (100) according to any one of the preceding claims, characterized in that the seal (2) is made of an elastomer, a rubber or a silicone. [9] Manufacturing method (100) according to any one of claims 2 to 8, characterized in that the functional portion (2a, 2a', 2a”) comprises a circular, V-shaped, arrow-shaped, lip-shaped, triangular section. [10] Manufacturing method (100) according to any one of claims 2 to 9, characterized in that the base (2b) has a straight, arrow-shaped, triangular or trapezoidal cross-section. [11] Manufacturing method (100) according to the preceding claim, characterized in that the base (2b) has holes (10). [12] Manufacturing method (100) according to any one of claims 1 to 11, characterized in that the closing step (150) of the mold (50) includes a substep of moving a part of the mold so as to apply the seal to the preform. [13] Manufacturing method (100) according to any one of claims 1 to 12, characterized in that the mold (50) comprises a first part and a second part, each first part and second part comprising a cavity intended to receive the preform (9). [14] Composite material part obtained by the manufacturing process (100) according to any one of claims 1 to 13, characterized in that the composite material part comprises the fibrous reinforcement densified by the matrix and at least one joint (2) thermocompressed with the fibrous reinforcement and the matrix, the base (2b) being configured so as to be extracted and replaced.

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