Method for producing a component made of a composite material and having a protected element, and

Abstract

The invention relates to a component (20) made of composite material for a turbine engine, in particular for an aircraft, comprising:-a shell layer (22) of composite material having an inner surface (28) and an outer surface (26), the shell layer of composite material comprising continuous fibers; and-at least one element (24) extending along a respective extension direction (X), each element (24) comprising a body (30) extending from an inner surface (28) of the shell layer to a free end (32) along a height direction (Z) different from the extension direction, each body (30) being connected to the inner surface by at least one fillet (36, 36 '), the body being made of a composite material mainly comprising discontinuous fibers; characterized in that the component (20) further comprises an additional shell layer (40) of continuous fibres covering at least one fillet connecting the body to the inner surface of the shell layer.

Description

Technical Field

[0001] This invention relates to the field of components made of composite materials consisting of fiber reinforcements densified by a matrix, particularly turbine engine components. Specifically, the invention targets components comprising elements, such as reinforcing members or U-shaped clips, which protrude from a plane relative to the surface of the component and are integrally formed.

[0002] The present invention also relates to a method for producing such a component. Background Technology

[0003] Background art specifically includes document US2004 / 0175533A1.

[0004] It is well known that various turbine engine components (especially aircraft turbine engine components) can be made of composite materials to improve the thermomechanical drag resistance of the individual turbine engine components and reduce their mass.

[0005] Some composite materials typically consist of fiber reinforcements and a matrix.

[0006] Several techniques have been identified for producing parts made of composite materials, including resin transfer molding (RTM), thermoplastic injection, and hot pressing. RTM injection requires fiber reinforcement with continuous fibers in most cases.

[0007] Many turbine engine components include elements that protrude from a plane, such as reinforcing members, U-shaped clips, ribs, and gusset plates.

[0008] However, these protruding elements can rise to a considerable height relative to the thickness of the protruding element (the lateral dimension of the protruding element) or relative to the surface on which the protruding element is located. This is the case, for example, with U-shaped ribs that rise to a height of 30 mm to 50 mm and have a thickness of 3 mm to 10 mm. In such cases, it can sometimes be difficult to guide the material to fill the entire shape of the protruding element. Furthermore, the material structure at the root of the element may exhibit significant mechanical weaknesses.

[0009] The object of the present invention is to provide a solution for improving a method of producing components by hot pressing and thermal creep, the components being particularly for turbine engines, the components being made of composite materials and having at least one raised element, the raised height of which is higher than the surface on which the raised element is located, while giving the mating area optimal mechanical properties. Summary of the Invention

[0010] This invention relates to a method for producing a component made of composite materials, particularly for aircraft components, comprising a composite shell having an inner surface and an outer surface, and at least one element extending along a respective extension direction, each element comprising a body extending from the inner surface of the shell to a free end along a height direction different from the extension direction, each body being connected to the inner surface by at least one connecting fillet. The method includes the following steps: - The step of supplying a first fiber preform, the first fiber preform being configured to form a shell and comprising continuous fibers; - The step of supplying a second fiber preform, which is configured to form the body of an element and mainly comprises discontinuous fibers; - The step of supplying a third fiber preform, which is configured to form an additional shell and includes continuous fibers; - The step of arranging an assembly formed by a first fiber preform, a second fiber preform, and a third fiber preform in a molding apparatus including a punch and a matrix, such that discontinuous fibers of the second fiber preform are arranged in clusters on the first preform to form the body of at least one element, and the third fiber preform is shaped and arranged to at least partially cover the clustered discontinuous fibers of the second preform. - The step of hot-pressing the components to form the part; and - The step of demolding the components to form the parts.

[0011] Therefore, the present invention provides a simple solution to at least some of the aforementioned disadvantages. The present invention provides a reliable method for producing a component comprising at least one raised element, the raised height of which is higher than the surface on which the raised element is located. In fact, one or more additional layers located above the shell and covering the connecting rounded corners ensure very good mechanical strength regulated by fibers rather than solely by resin.

[0012] The method according to the invention may include one or more of the following features, either individually or in combination with each other in any technically possible combination: - The third preform configured to form an additional shell includes slots, each slot extending along an associated extension direction of at least one element, and discontinuous fibers are arranged in clusters between the first fiber preform and the third fiber preform, aligned with the slots of the third preform. - The third preform configured to form an additional shell includes segments of multiple continuous fibers arranged to form orifices aligned with elements of the component to be formed, and discontinuous fibers are clustered between the first fiber preform and the third fiber preform, aligned with the orifices of the third preform. - The orifice of the third preform is partially closed by the corresponding section forming the orifice, so that during the hot pressing step, clusters of discontinuous fibers flow through the orifice to form elements of the part to be produced; - The length of the discontinuous fibers in the second fiber preform is less than 50 mm, preferably less than 30 mm; - The first fiber preform, the second fiber preform, and the third fiber preform are pre-impregnated with resin; - The third preform includes a first layer and a second layer. The first layer includes a first unidirectional fiber, which is oriented at an angle between +30° and +150°, preferably between +40° and +140°, relative to the extension direction of at least one connecting fillet. The second layer includes a second unidirectional fiber, which is oriented at an angle between -30° and -150°, preferably between -40° and -140°, relative to the extension direction of the associated protruding element. The extension direction of the second unidirectional fiber is symmetrical to that of the first fiber.

[0013] The present invention also relates to a component made of composite materials for a turbine engine, particularly a turbine engine for an aircraft, the component comprising: - A composite shell having an inner surface and an outer surface, the composite shell comprising continuous fibers; and - At least one element extending along a corresponding extension direction, each element comprising a body extending from the inner surface of the shell to a free end along a height direction different from the extension direction, each body being connected to the inner surface by at least one connecting fillet, the body being made of a composite material primarily comprising discontinuous fibers.

[0014] According to the invention, the component further includes an additional shell of continuous fibers, which at least covers at least one connection fillet on the inner surface of the shell that connects the body to the shell.

[0015] Components according to the invention may include one or more of the following features, either individually or in any technically possible combination: - The continuous fibers of the additional shell extend in orientation from the inner surface of the shell to the body of at least one element, and at least one orientation of the continuous fibers of the additional shell extends in a curved path along at least one connecting fillet. - The component is an open panel, and at least one element is a U-shaped clip or reinforcement.

[0016] Advantageously, the component is manufactured by implementing the method according to the invention as described above.

[0017] The present invention also relates to a turbine engine comprising components made of composite materials as described above. Attached Figure Description

[0018] The invention will be better understood from the following detailed description, including embodiments given by way of illustration and presented as non-limiting examples with reference to the accompanying drawings, which can serve to complete the understanding of the invention and the disclosure of embodiments thereof, and, where appropriate, help to define the invention, in which: - Figure 1 This is a partial axial cross-sectional view of an example of a turbine engine to which the present invention is applied; - Figure 2 This is a schematic cross-sectional view of an example of a component including three protruding elements according to the present invention; - Figure 3 This is a schematic three-dimensional view of an example of a component made of composite material according to the present invention, the component including protruding elements such as reinforcing members; - Figure 4 This is a schematic three-dimensional view of another example of a component made of composite material according to the invention, which includes two protruding elements such as a double U-shaped clamp component; - Figure 5 This is a block diagram illustrating a method for producing a component according to the invention; - Figure 6 The perspective view schematically illustrates an example of the stacking of continuous fiber layers forming a first preform and the positioning of discontinuous fibers forming a second preform, which are aligned with protruding elements of the part to be produced. - Figure 7 yes Figure 6 A cross-sectional view; - Figure 8 An example of a stack of continuous fiber layers forming a third preform is shown schematically in perspective view, the layer including triangular slots aligned with protruding elements of the part to be produced; - Figure 9 It has tools Figure 8 A cross-sectional view; - Figure 10 A schematic perspective view of the final part obtained is shown; - Figure 11 yes Figure 10 A cross-sectional view; - Figure 12 It is a three-dimensional schematic diagram of the steps for arranging the first preform, the second preform, and the third preform, wherein the third preform includes a slot aligned with a protruding element of the part to be produced; - Figure 13This is a three-dimensional schematic diagram of another example of the steps for arranging the first preform, the second preform, and the third preform, wherein the third preform includes two sections with parallel edges on both sides of the raised area of ​​the part to be produced; - Figure 14 This is a schematic cross-sectional view of another example of the steps for arranging the first, second, and third preforms, the third preform comprising two segments having parallel edges on either side of the raised region of the part to be produced, the two segments slightly overlapping above the raised region of the part to be produced; and - Figure 15 yes Figure 14 A schematic cross-sectional view during the hot pressing step, with particular emphasis on the creep of discontinuous fibers from the second preform through a slot in the third preform.

[0019] Elements that have the same function in different embodiments have the same reference numerals in the drawings.

[0020] The accompanying figures are not drawn to scale. In particular, the thickness has been enlarged to make the figures easier to read. Detailed Implementation

[0021] Figure 1 A partial axial cross-section of a turbine engine 1 with a longitudinal axis A is shown. The turbine engine 1 includes various parts and / or components that may be made of composite materials. Of course, the invention is generally applicable to all parts made of composite materials with complex shapes (e.g., profiles with varying cross-sections), and is applicable to various fields where parts enable force transmission and reduce mass while being economical.

[0022] Figure 1 The turbine engine 1 is constructed as a dual-flow, dual-body turbine engine mounted on an aircraft. The turbine engine 1 includes a fan 2, which operates according to the flow of gas within the turbine engine and, in this case, according to the longitudinal axis A (and even in...). Figure 1(From left to right) It is installed upstream of the gas generator 3 or the engine. The gas generator 3 includes, from upstream to downstream, a low-pressure compressor 4a, a high-pressure compressor 4b, a combustion chamber 5, a high-pressure turbine 6a, and a low-pressure turbine 6b. The fan 2 includes a plurality of fan blades 7 extending along the radial axis R, and the free ends of the plurality of fan blades 7 are surrounded by a fan housing 8. The longitudinal axis A is perpendicular to the radial axis R and also perpendicular to the transverse axis T. The fan housing 8 is supported by a nacelle 9, and the nacelle 9 and the fan housing 8 are centered on the longitudinal axis A. The fan 2 divides the air entering the turbine engine into a primary airflow and a secondary airflow. The primary airflow passes through the gas generator and is particularly in the primary duct 10, while the secondary airflow flows around the gas generator in the secondary duct 11. An outlet guide vane (OGV) 12 is located downstream of the fan blades 7, extends around the longitudinal axis A, and passes through the secondary duct to straighten the secondary airflow.

[0023] Figure 2 A schematic cross-sectional view of a first example of a component 20 made of composite material according to the present invention is shown. Figure 3 and Figure 4 Also shown are components 20 made of composite materials having fiber reinforcements embedded in a matrix. In particular, component 20 includes one or more protruding elements. Figure 3 Component 20 in the middle is, for example, a component having a reinforcing member as a protruding element, while Figure 4 For example, a component in the design is a component with a double U-shaped clamp.

[0024] More specifically, component 20 includes a composite shell 22 and at least one so-called protruding element 24, such as a reinforcement ( Figure 3 ), ribs, U-shaped clips ( Figure 4 )wait.

[0025] exist Figures 2 to 4 In the example shown, the so-called main shell 22 extends along the extension plane XY and defines an outer surface 26 and an inner surface 28, which are spaced apart from each other along the thickness direction Z perpendicular to the extension plane XY.

[0026] For example, the outer surface 26 is configured to face the passenger compartment and is visible, while the inner surface 28 is not visible once component 22 is in place.

[0027] Each of the so-called one or more protruding elements 24 includes a body 30 that protrudes along the thickness direction Z from the inner surface 28 of the shell to the corresponding free end 32.

[0028] In addition, each body 30 extends on the inner surface 28 of the shell 22 in an associated extension direction.

[0029] exist Figure 2 In the example shown, element 24 extends in the direction of X. Figure 4 In the example shown, the bodies 30 of the two elements 24 (specifically the U-shaped clips) extend parallel to each other in the same extending direction X.

[0030] Alternatively, the body 30 of element 24 may extend in different directions and intersect at intersection points, such as, for example, in Figures 6 to 11 As shown in the image.

[0031] Element 24 can be uniformly spaced along the transverse direction Y, which is perpendicular to the extension direction X and the thickness direction Z, such as in particular in Figure 2 As shown in the image.

[0032] Each body 30 includes two sides 34 that extend between the inner surface 28 and the free end 32 of the body 30 of the corresponding element 24, and are opposite to each other in the transverse direction Y. The sides 34 extend primarily in the parallel plane XZ.

[0033] Furthermore, each body 30 is connected to the inner surface 28 via at least one connecting fillet 36. In other words, each body 30 opens toward the inner surface 28.

[0034] exist Figure 3 In the example shown, each of the two sides 34 of the body 30 of the reinforcement 24 flares outward toward the inner surface 28 of the shell. Each connecting fillet has a curved profile in a plane transverse to the direction X in which the reinforcement extends.

[0035] Additionally, the body 30 of each element 24 may also include two additional side surfaces 34' extending between the inner surface 28 and the free end 32 of the respective element 24's body 30, facing each other in the extension direction X. Therefore, the additional side surfaces 34' extend primarily in the parallel plane YZ. The additional side surfaces 34' may also be connected to the inner surface 28 via connecting fillets 36', such as... Figure 4 The example of the double U-shaped clamp component is shown. The body 30 of each U-shaped clamp opens outward toward the inner surface 28 of the shell 22.

[0036] According to the invention, component 20 further includes an additional shell layer 40 made of a composite material of continuous fibers, which at least covers one or more connecting fillets 36, 36' of the body 30 to the inner surface 28 of the shell layer 22. More specifically, the additional shell layer 40 extends along an extension plane of the main shell layer 22 (i.e., along the extension plane XY) and defines an outer surface 46 and an inner surface 48, which are spaced apart from each other along a thickness direction Z perpendicular to the extension plane XY. When the outer surface 46 of the additional shell layer 40 is not in contact with the body of the component 24, particularly with its connecting fillets 36, 36', the outer surface 46 of the additional shell layer 40 contacts the inner surface 28 of the main shell layer. The inner surface 48 of the additional shell layer 40 forms the inner surface of the final component 20.

[0037] The additional shell 40 can also partially cover the sides 34, 34' of the body 30 of element 24 near the connecting fillets 36, 36'.

[0038] exist Figure 3 In the example shown, the additional shell 40 is formed by two segments 40A and 40B, each segment 40A and 40B covering the connecting fillet 36 of the side 34 of the reinforcement, and extending in the opposite direction, above the inner surface 28 of the main shell 22, along a direction Y perpendicular to the extension direction of the element 24 (i.e. the reinforcement of the component).

[0039] exist Figure 4 In the example shown, the additional shell 40 is formed of a single continuous material, and each element includes an aperture 42 through which the element extends from the inner surface 28 of the main shell 22 to a free end 32. Each aperture 42 is defined by a periphery 44 that matches the shape of the body 30 of the element (particularly the U-shaped clip), which passes through the aperture 42 to cover the connecting fillets 36, 36' or all connecting fillets 36, 36' of the body of the element 24.

[0040] In addition, the continuous fibers of the additional shell 40 extend in orientation from the inner surface 28 of the main shell 22 to the body 30 of each element 24, and at least one orientation of the continuous fibers of the additional shell 40 extends along a curved path along the corresponding connecting fillet, i.e., there is overlap.

[0041] Figures 2 to 4 The component 20 shown, made of composite material, is composed of fiber reinforcements. The fiber reinforcements are configured to increase the strength of the final component 20, particularly at the walls or joints of the component. The fiber reinforcements are densified by matrix densification to obtain a final rigid component with protruding elements 24.

[0042] More specifically, the main shell 22 is composed of a first fiber reinforcement, particularly having continuous fibers; one or more protruding elements 24 are composed of a second fiber reinforcement, mainly having discontinuous fibers; and the additional shell 40 is composed of a third fiber reinforcement, having continuous fibers. Each fiber reinforcement is obtained from a fiber preform as described below.

[0043] Now refer to Figure 5 A detailed description of the manufacturing method 100 of such a component made of composite material according to the present invention. Figure 5 This is a flowchart illustrating the manufacturing method.

[0044] The method includes a step 110 of supplying a first fiber preform PF1, referred to as a shell preform, which is configured to form a shell and includes continuous fibers.

[0045] Preferably, the fibers of the first fiber preform PF1 are pre-impregnated with an impregnating polymer resin (or matrix). In other words, the first preform PF1 is made of a composite material called a prepreg, which includes fibers embedded in the resin. The impregnating resin particularly includes thermoplastic or thermosetting resins. Examples of thermoplastic resins are polyamides, polyetheretherketones, polyetherketoneketones, polyphenylene sulfides, or polyaryletherketones. Thermosetting resins include, for example, epoxides or polyimides. The fibers are organic, mineral, metallic, thermoplastic polymer fibers, or thermosetting polymer fibers, or mixtures of these fibers. Examples of fibers are carbon fibers, glass fibers, or aromatic polyamide fibers.

[0046] The shell preform PF1 primarily comprises continuous fibers arranged in multiple layers, such as unidirectional fiber webs (with their extension directions differing from each other), fabrics, or multiaxial multilayer web mats known as non-crimp fabrics (NCF). The mat consists of stacked portions of multiple layers of fibers, with the fibers oriented differently from each other. Advantageously, the continuous fibers provide high mechanical properties to the main shell 22. The shell preform PF1 may also contain discontinuous fibers, for example, to provide the volume of adapting material required to supply the variable thickness of the part to be produced.

[0047] The method includes a step 120 of supplying a second fiber preform PF2, referred to as a body preform, which is configured to form the body of the reinforcement and mainly comprises discontinuous fibers.

[0048] The main precast component PF2 is primarily composed of discontinuous fibers in the following forms: - Bulk molding compound (BMC) consists of fibers of finite length (typically less than 50 mm). - Sheet molding compound (SMC) type fabrics or mats, comprising continuous or discontinuous fibers mainly randomly distributed in the plane of the fabric / mat, or - Material fragment pads, including oriented fibers (“discontinuous long fibers” (DLF)) obtained from fabric sheets or unidirectional fiber layer meshes, or even - Finished roving sheet.

[0049] Advantageously, the length of the discontinuous fibers in the main precast component PF2 is less than 50 mm, preferably less than 30 mm.

[0050] Preferably, the second fiber preform PF2 is also made of a prepreg composite material, i.e., it includes fibers embedded in resin. Preferably, the resin used for the second fiber preform PF2 is the same as the resin used for the first fiber preform PF1.

[0051] The volume of material in the main preform PF2, determined for the production of component 20 (more specifically, protruding element 24), must be at least equal to the volume of the protruding element 24 to be formed. Preferably, the volume is slightly larger than the volume of the protruding element 24 to be formed to promote good compaction of the material during hot pressing. Material health (minimizing porosity) is achieved by compressing the material, and requires that the amount of material placed in the tooling be at least equal to the volume of the mold to be cast. The material of the preform PF2 may be arranged close to the protruding element 24 to be formed to limit the creep distance to be covered in order to reach the protruding area.

[0052] The method includes a step 130 of supplying a third fiber preform PF3, which is configured to form an additional shell. The third preform PF3 comprises only continuous fibers, such as a unidirectional fiber web or a bidirectional fabric or a unidirectional to multidirectional NCF.

[0053] The third preform PF3 comprises one or more layers of continuous fibers, the fibers extending in different directions from each other. Advantageously, the continuous fibers provide high mechanical properties for the additional shell 40.

[0054] Furthermore, the continuous fibers of the third fiber preform PF3, which is configured to form the additional shell 40, are configured to extend in multiple orientations from the inner surface 28 of the main shell 22 to the body 30 of each element 24 in the final component 20. At least one orientation of the continuous fibers of the third fiber preform PF3 is configured to extend along a curved path along a corresponding connecting fillet, i.e., there is overlap.

[0055] The third fiber preform PF3 may comprise one or more layers of continuous fibers. In the case of multiple layers, the continuous fibers in the same layer may have a single common direction that varies with the layers. For example, the first layer comprises a first unidirectional fiber oriented at an angle between +30° and +150°, preferably between +40° and +140°, relative to the extension direction X of the connecting fillet, and the second layer comprises a second unidirectional fiber oriented at an angle between -30° and -150°, preferably between -40° and -140°, relative to the extension direction X, the second unidirectional fiber being symmetrical to the first fiber with respect to the extension direction X of the associated protruding element.

[0056] According to another example, the third fiber preform is a fabric having warp yarns oriented between +35° and +55° along the extension direction of the associated protruding element (especially at the connecting fillet 36) and weft yarns oriented between +125° and +145°.

[0057] Furthermore, the third fiber preform PF3, configured to form the additional shell 40, includes a free end (fiber end edge) extending beyond the base of the connecting fillets 36, 36' between the inner surface 48 and the sides 34, 34' of the protruding element 24, to cover the discontinuous fibers of the shell preform PF1 and partially cover the main body preform PF2, while providing a channel for the creep of the discontinuous fibers of the main body preform PF2 as described below, and to form a surface capable of connecting radius 36.

[0058] In this way, the discontinuous fibers present in preform PF2 lead to a tensile failure mode, rather than a peeling mode. Furthermore, the continuous fibers on the inner surface 48 lead to a fiber fracture mode, rather than an interfiber fracture mode. These two factors increase the fracture level and make it repeatable.

[0059] Next, the method includes forming an assembly (such as) from a shell preform PF1, a main body preform PF2, and a third preform PF3. Figures 6 to 11 (As shown) Step 140 is arranged in the molding apparatus 50. Figure 6 and Figure 8 A perspective view showing the prefabrication assembly steps is provided, while Figure 10 The final component is shown.

[0060] Figure 7 , Figure 9 and Figure 11 They are shown respectively Figure 6 , Figure 8 and Figure 10 A cross-sectional view. For clarity, only... Figure 9 The image shows a molding apparatus or mold 50 for producing components according to the invention.

[0061] refer to Figure 9 The device 50 includes a base 52 and a cover or punch 54, the cover or punch 54 being mounted to slide vertically in the Z direction within the base and together with the base defining a compression chamber 56.

[0062] The base 52 has a main surface 58 facing the cover 54. This main surface 58 has protrusions, and more specifically, cavities 60 extending from the main surface 58 and shaped to form protruding elements 24 of the final component 20. The shape and arrangement of the cavities 60 correspond to the shape and arrangement of the elements 24 of the component to be produced. Therefore, each cavity 60 extends from the main surface 48 to the bottom 62.

[0063] In the example shown, the final component ( Figure 10 It includes triangular reinforcing member 24.

[0064] Figure 6 and Figure 7 The stacking of multiple continuous fiber layers (three continuous fiber layers in the example shown) forming the shell preform PF1 is schematically illustrated in perspective and cross-section, and an example of discontinuous fibers forming the body preform being clustered and positioned on the shell preform PF1, aligned with the protruding element of the part to be produced. Advantageously, the discontinuous fibers are arranged in clusters or piles close to the base of the element 24 protruding from the main shell, thereby reducing the creep length of the material of the second preform PF1 to fill the cavity and form the body of the element 24.

[0065] In the example shown, discontinuous fibers are arranged in triangular clusters, which correspond to the shape and size of the element 24 (e.g., a triangular reinforcement) of the part 20 to be manufactured. Figure 10 ).

[0066] Figure 8 and Figure 9 The assembly, formed by the shell preform PF1, the main body preform PF2, and the third preform PF3, is schematically shown in perspective and cross-section. The third preform PF3 is stacked on top of... Figure 6 and Figure 7 On the stack shown. The third preform PF3 includes a channel 70 aligned with the protrusion element 24 of the part to be produced. In the example shown, the channel 70 has a triangular shape, adapted to the shape of the triangular clusters of discontinuous fibers forming the main preform PF2, and particularly adapted to the triangular geometry of the cavity 60. The third fiber preform PF3 thus formed is arranged to at least partially cover the clustered discontinuous fibers of the second preform PF2, while leaving the channel 70 open for the creep of the discontinuous fibers of the second preform PF2 to form the protrusion element 24 of the part to be produced.

[0067] exist Figure 8 and Figure 10 In this embodiment, the inner surface layer of the third fiber preform PF3 consists of a first portion and a second portion. The first portion is disposed within the contour of the protruding element 24, and the second portion forms the entire outer periphery outside the contour of the protruding element 24. Alternatively, one or both portions of the inner surface layer of the third fiber preform PF3 may consist of two or more distinct segments to improve the suitability of the fiber orientation of each segment of the layer relative to the different orientations of the protruding element 24 to be formed in the XY plane.

[0068] An assembly formed by a first fiber preform PF1, a second fiber preform PF2, and a third fiber preform PF3 is mounted in a molding apparatus 50 such that the channel 70 of the third preform PF3 and the clustered discontinuous fibers of the second preform PF2 are positioned aligned with the cavity 60. Figure 9 In one embodiment, three preforms PF1, PF2, and PF3 are assembled stacked on top of each other using a positioning template and then installed in a molding apparatus. In another embodiment, preforms PF1, PF2, and PF3 are installed one after another in the molding apparatus, stacked on top of each other. The molding apparatus 50 is then closed.

[0069] Figure 12 An example of such component E is schematically shown in perspective, wherein the third preform PF3 includes a slot 72 for each protruding element 24 to be formed. In the example shown, only one slot 72 exists.

[0070] Each slot 72 extends along the associated extension direction X or extension direction (if applicable) of the element 24 to be formed.

[0071] The discontinuous fibers of the main preform PF2 are arranged in clusters between the first shell preform PF1 and the third preform PF3, aligned with the slot 72 in the third preform PF3, as shown below. Figure 9 and Figure 12 As shown.

[0072] This slot 72 can be formed by a cut in the third preform PF3.

[0073] Alternatively, the third preform PF3, configured to form the additional shell 40, comprises segments of multiple continuous fibers. These segments are arranged to form channels 70 or apertures aligned with the element 24 to be formed in the component, such that the free edge ends of the channels 70 in the preform PF3 extend into the connecting fillet 36 at the base of the protruding element 24. Discontinuous fibers are clustered between the first fiber preform PF1 and the third fiber preform PF3, aligned with the channels in the third preform PF3.

[0074] Figure 13 An example of such component E' is schematically shown in perspective, wherein the third preform PF3 comprises two portions 74A and 74B of continuous fibers arranged to form a channel 70 aligned with the element 24 to be formed in the component. The channel 70 is defined by edges 76A and 76B of the portions 74, which are arranged on either side of the protruding element to be produced. In the example shown, the edges are parallel and extend along the direction of extension. Clusters of discontinuous fibers are arranged between the first preform PF1 and the third fiber element PF3, aligned with the channel in the third preform PF3. This third preform enables the formation of an additional shell 40 divided into two segments 40A and 40B, as... Figure 3 Like the components in the middle. Each segment 40A, 40B overlaps with the connecting fillet 36 of the side 34 of the reinforcement and extends in the opposite direction, above the inner surface 28 of the main shell 22, in the opposite direction along the direction Y perpendicular to the extension direction of the element 24 (i.e. the reinforcement of the component).

[0075] Furthermore, when the preform PF3 is in its flat state and when preforms PF1 and PF2 are assembled before the hot pressing step, the edges 76A and 76B of the portion 74 arranged on both sides of the protruding element to be produced can overlap by a distance D of a few millimeters, that is, one edge 76A is on top of the other edge 76B, as shown below. Figure 14 As shown. Advantageously, this configuration allows each segment 40A, 40B of the additional shell 40 to cover and mount on a portion of the side of the body of the final component and on the corresponding connecting fillet of the body. In this case, during the hot pressing step, during the creep of the discontinuous fiber material of the second preform, the channel 70 opens, as... Figure 15 As shown. Before creep begins, channel 70 is closed by overlapping the edges 76A and 76B of portion 74 of the third preform PF3. Figure 14 ).

[0076] The method then proceeds to step 150, which involves hot-pressing the components to form the final part. This hot-pressing step allows for compression of the materials (i.e., all three fiber preforms PF1, PF2, PF3) to cause the discontinuous fiber material of the main preform PF2 to creep, filling the cavity 60 of the mold up to its bottom 62 to form the protruding element 24. During this hot-pressing step, the discontinuous fiber material of the main preform PF2 passes through one or more channels 70 of the third fiber preform PF3 to fill the cavity 60 of the mold. Thus, the final part 20 includes an additional shell 40 (which covers the connection fillets 36, 36' of the body of the protruding element 24) to ensure good mechanical properties of the joint area between the protruding element 24 and the main shell 22, even if the element protrudes significantly relative to the surface on which the element is located in the main shell.

[0077] This method is particularly advantageous for resin-preimpregnated fiber preforms. The matrix associated with the fibers acts as a lubricant, thereby inducing discontinuous fiber creep in the second preform PF2 to form protruding elements. During the hot-pressing step, the component material must be heated to sufficiently reduce the viscosity of the matrix, typically to less than 100 poise, preferably to less than 10 poise.

[0078] Preforms PF1, PF2, and PF3 are bonded together by hot pressing. Fiber preforms are cured by chemical crosslinking or polymerization in the case of thermosetting resins, and by heating and cooling in the case of thermoplastic matrices.

[0079] Therefore, the body 30 of the element 24 is fixed to the inner surface 28 of the main shell 22, and more precisely bonded to the inner surface 28 of the main shell 22 by the polymer matrix of the composite material of the additional shell 40 and the preform.

[0080] The method then includes step 160 of demolding the produced part to obtain the final part, followed by step 170 of finishing the part (deburring, finishing, etc.) to obtain the final part.

[0081] In particular, when the ribs extend to a very high height relative to the surface on which the ribs are located, the present invention, as described, advantageously makes it easy and robust to produce such ribbed parts by hot pressing.

[0082] Of course, the present invention is not limited to the embodiments described above, which are provided merely as examples. The present invention encompasses various modifications, alternatives, and other variations that can be conceived by those skilled in the art within the framework of the present invention, and in particular all combinations of the various embodiments described above, which can be carried out individually or in combination.

[0083] Specifically, the invention described herein implements a composite material referred to as a prepreg, which comprises fibers embedded in resin to form a fiber preform assembly. However, the method can also be applied to so-called “dry” fiber preforms, i.e., preforms comprising fibers held together by an adhesive (e.g., an aqueous or soap-based adhesive). In this case, resin is applied to the preform, for example by a resin film disposed between the cover and the first fiber preform, before the molding apparatus is closed, and the preform is impregnated during hot pressing. Alternatively, the resin can be injected into the compression chamber of the molding apparatus after the molding apparatus is closed. The method must then include the steps of removing the adhesive and then introducing a matrix between the fibers to bond the assembly.

Claims

1. A component (20) made of composite material for a turbine engine, particularly a turbine engine for an aircraft, the component comprising: - A shell (22) of a composite material having an inner surface (28) and an outer surface (26), the shell of the composite material comprising continuous fibers; as well as - At least one element (24) extending along a corresponding extension direction (X), each element (24) comprising a body (30) extending from the inner surface (28) of the shell along a height direction (Z) different from the extension direction to a free end (32), each body (30) being connected to the inner surface by at least one connecting fillet (36, 36'), the body being made of a composite material mainly comprising discontinuous fibers; The component (20) is characterized in that it further comprises an additional shell (40) of continuous fibers, the additional shell covering at least one connection fillet on the inner surface of the body to which the body is connected.

2. The component according to claim 1, wherein, The continuous fibers of the additional shell (40) extend in orientation from the inner surface (28) of the shell (22) to the body (30) of the at least one element (24), and at least one orientation of the continuous fibers of the additional shell (40) extends in a curved path along the at least one connecting fillet (36, 36').

3. The component according to claim 1 or 2, wherein, The component is an open panel, and the at least one element is a U-shaped clip or a reinforcement.

4. A method for producing a component made of composite material according to any one of the preceding claims, the method comprising the steps of: - Step (110) of supplying a first fiber preform (PF1), the first fiber preform being configured to form the shell (22) and comprising continuous fibers; - Step (120) of supplying a second fiber preform (PF2), the second fiber preform being configured to form the body (30) of the element (24) and primarily comprising discontinuous fibers; - Step (130) of supplying a third fiber preform (PF3), the third fiber preform being configured to form the attachment shell layer (40) and comprising continuous fibers; - The step (140) of arranging the assembly formed by the first fiber preform (PF1), the second fiber preform (PF2) and the third fiber preform (PF3) in a molding apparatus (50) including a punch (54) and a matrix (52) such that the discontinuous fibers of the second fiber preform are arranged in clusters on the first preform to form the body of the at least one element, and the third fiber preform is shaped and arranged to at least partially cover the clustered discontinuous fibers of the second preform; - Step (150) of hot pressing the component to form the part. as well as - Step (160) of demolding the component to form the part.

5. The method according to claim 4, wherein, The third preform (PF3) configured to form the attachment shell (40) includes slots (72), each slot (72) extending along the associated extension direction of the at least one element (24), and the discontinuous fibers are arranged in clusters between the first fiber preform (PF1) and the third fiber preform (PF3) and aligned with the slots (72) of the third preform (PF3).

6. The method according to claim 4, wherein, The third preform (PF3) configured to form the attachment shell (40) includes a plurality of continuous fiber segments (74) arranged to form apertures (70) aligned with elements of the component to be formed, and the discontinuous fibers are arranged in clusters between the first fiber preform (PF1) and the third fiber preform (PF3) and aligned with the apertures of the third preform (PF3).

7. The method according to claim 6, wherein, The orifice (70) of the third preform (PF3) is partially closed by the corresponding section forming the orifice, such that during the hot pressing step, the clustered discontinuous fibers flow through the orifice to form elements of the part to be produced.

8. The method according to any one of claims 4 to 7, wherein, The length of the discontinuous fibers in the second fiber preform (PF2) is less than 50 mm, preferably less than 30 mm.

9. The method according to any one of claims 4 to 8, wherein, The first fiber preform (PF1), the second fiber preform (PF2), and the third fiber preform (PF3) are pre-impregnated with resin.

10. The method according to any one of claims 4 to 9, wherein, The third fiber preform (PF3) includes a first layer and a second layer. The first layer includes a first unidirectional fiber oriented at an angle between +30° and +150°, preferably between +40° and +140°, relative to the extension direction of the at least one connecting fillet (36, 36'). The second layer includes a second unidirectional fiber oriented at an angle between -30° and -150°, preferably between -40° and -140°, relative to the extension direction. The extension direction of the second unidirectional fiber is symmetrical to that of the first fiber relative to the associated protruding element.

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