Repair or restoration of production of parts made of composite materials

Abstract

A gas turbine component (10) made of composite material, the component comprising a fibrous reinforcement exhibiting a three-dimensional weaving between a plurality of warps and a plurality of wefts, the fibrous reinforcement being densified by a matrix. In an axial direction, the densified fibrous reinforcement extends a width between a downstream end and an upstream end, while in a radial direction, the densified fibrous reinforcement extends a thickness between an inner surface (11) and an outer surface (12). The fibrous reinforcement densified by the matrix comprises a recessed portion extending over the entire thickness of the fibrous reinforcement. A filler (50) made of composite material is present in the free volume of the component defined by the recessed portion, the filler (50) comprising a fibrous preform exhibiting a three-dimensional weaving, the fibrous preform being densified by a matrix.

Description

[0001] This application is a divisional application of the PCT international invention patent application filed by Safran Group on February 24, 2020, with application number 202080024415.6 (international application number PCT / FR2020 / 050341) entitled "Repairing or restoring the production of parts made of composite materials". Technical Field

[0002] This invention relates to gas turbine components made of composite materials, and more specifically, but not exclusively, to gas turbine housings for aircraft engines, such as fan housings. Background Technology

[0003] In the gas turbine engine of an aircraft, the fan casing fulfills several functions. In addition, the fan casing defines the air inlet of the engine, optionally supports wear-resistant material opposite the tips of the fan blades and / or sound-absorbing structures for acoustic treatment at the air inlet of the engine, and incorporates or supports shielding components.

[0004] Housings previously made of metallic materials, such as fan housings, are now made of composite materials, specifically fiber preforms densified with an organic matrix. This allows for the manufacture of components with a lower total mass than those identical components when made of metallic materials, while simultaneously possessing, if not superior, at least equal mechanical strength. The manufacture of composite fan housings is specifically described in document US 8,322,971.

[0005] While using composite housings can reduce the overall weight of the engine, repairs in case of damage or localized rework of non-compliant areas within the composite housing can pose challenges. In fact, existing solutions, such as those described in document US2007 / 0095457, involve bonding pre-impregnated fiber patches, possibly composed of one or more fiber layers, to damaged or reworked areas of the composite component. However, this type of solution carries the risk of the bonded patch peeling off. Therefore, it is necessary to create an additional mechanical connection between the patch and the composite component, such as using bolt-type members. Adding this connection increases the component's mass and affects the initial composite structure (creating channels in the composite component to insert the connecting member). This issue also arises when repairing or reworking other gas turbine composite components. Summary of the Invention

[0006] The purpose of this invention is to provide a solution for repairing or reworking composite gas turbine components, such as housings, without the disadvantages of prior art.

[0007] This objective is achieved by means of a gas turbine component made of composite materials, comprising a fiber reinforcement having a three-dimensional braid between multiple warp and weft threads, the fiber reinforcement being densified by a matrix, the densified fiber reinforcement extending width between downstream and upstream ends in the axial direction, and extending thickness between inner and outer surfaces in the radial direction, characterized in that the matrix-densified fiber reinforcement includes at least one hollowed-out portion extending through the entire thickness of the fiber reinforcement, and wherein a composite material filler is present in the free volume of the component defined by the at least one hollowed-out portion, the filler comprising a fiber preform having a three-dimensional braid, the fiber preform being densified by the matrix.

[0008] By using fillers that include three-dimensionally woven fiber preforms, repairs or reworks with high resistance to delamination are possible. Therefore, repairing damaged or non-conforming areas on components is particularly effective, while having a very limited impact on the overall quality of the component.

[0009] According to a first feature of the component of the invention, each hollow portion includes at least two opposing edges, each opposing edge including a first ramp and a second ramp, and the composite filler includes a first portion and a second portion, the first portion having a geometry complementary to the volume of a portion of the hollow portion defined between the first ramps of the opposing edges, and the second portion having a geometry complementary to the volume of another portion of the hollow portion defined between the second ramps of the opposing edges. In this way, the integration and mechanical strength of the filler in the hollow portion are optimized.

[0010] According to a second feature of the component of the invention, each opposing edge of the first and second bevels extends over a length corresponding to at least ten times the thickness of the component at the cut-out portion. This optimizes the transfer of mechanical loads to the bonding interface between the filler and the composite material structure of the component.

[0011] According to a third feature of the component of the invention, the first and second portions of the filler are joined together by weaving. This further enhances the mechanical strength of the filler.

[0012] According to a fourth feature of the component of the invention, the filler further includes at least one fastening member extending into the filler. Therefore, if necessary, the strength of the filler can be increased without affecting the composite structure of the component, since the fastening member(s) are fully integrated into the filler.

[0013] Another subject of the invention is a gas turbine engine for an aircraft having components according to the invention, such as a fan housing, and the aircraft includes one or more of these aircraft engines.

[0014] Another subject of the present invention is a process for repairing a composite material component of a gas turbine having a rotating shape, the component comprising a fiber reinforcement having a three-dimensional weave between multiple warp and weft threads, the fiber reinforcement being densified by a matrix, the densified fiber reinforcement extending width between a downstream end and an upstream end in the axial direction, and extending thickness between an inner surface and an outer surface in the radial direction, characterized in that the process comprises:

[0015] - Identify at least one damaged area in the component.

[0016] - The hollowed-out section is created by removing the composite material at the damaged area, thus forming a hollowed-out section that extends through the entire thickness of the fiber reinforcement.

[0017] - Fiber preforms for three-dimensional braided fillers

[0018] - The fiber preform of the filler is placed in the free volume of the component defined by the cut-out portion.

[0019] - Before or after placing the fiber preform of the filler into the hollowed-out portion, impregnate the preform with a matrix resin precursor.

[0020] - Resin is polymerized into a matrix to obtain a composite filler comprising a 3D woven fiber preform occupying a volume defined by a cutout.

[0021] According to a first feature of the repair process of the present invention, the fabrication of the hollow portion includes forming at least two opposing edges, each opposing edge including a first bevel and a second bevel, and the filler fiber preform includes a first portion and a second portion, the first portion having a geometry complementary to a portion of the volume of the hollow portion defined between the first bevels of the opposing edges, and the second portion having a geometry complementary to another portion of the volume of the hollow portion defined between the second bevels of the opposing edges.

[0022] A second feature of the repair process according to the invention includes that each opposite edge of the first and second bevels extends over a length corresponding to at least ten times the thickness of the component at the hollowed-out portion.

[0023] According to a third feature of the repair process of the present invention, the first and second parts of the filler fiber preform are joined together by weaving.

[0024] A fourth feature of the repair process according to the invention further includes integrating at least one fastening member into the filler.

[0025] The present invention also relates to a process for manufacturing composite material components for gas turbines, the process comprising weaving a fiber texture in the form of strips into a single piece by three-dimensional weaving, shaping the texture by winding it onto a support tool to form a fiber reinforcement of the component, and densifying the fiber reinforcement by a matrix, wherein the densified fiber reinforcement extends in width between a downstream end and an upstream end in the axial direction, and extends in thickness between an inner surface and an outer surface in the radial direction, characterized in that the process includes:

[0026] - Identify at least one non-conforming area in the component.

[0027] - The hollowed-out portion is manufactured by removing defective areas of the composite material, thereby forming a hollowed-out portion that extends through the entire thickness of the fiber reinforcement.

[0028] - Fiber preforms for three-dimensional braided fillers

[0029] - Place the filler fiber preform in the free volume of the component defined by the cut-out portion.

[0030] - Before or after placing the filler fiber preform into the hollowed-out portion, impregnate the preform with a matrix resin precursor.

[0031] - Resin is polymerized into a matrix to obtain a composite filler containing a 3D woven fiber preform occupying a volume defined by a cutout portion.

[0032] According to a first feature of the manufacturing process of the present invention, the fabrication of the hollow portion includes forming at least two opposing edges, each opposing edge including a first bevel and a second bevel, and the filler fiber preform including a first portion and a second portion, the first portion having a geometry complementary to a portion of the volume of the hollow portion defined between the first bevels of the opposing edges, and the second portion having a geometry complementary to another portion of the volume of the hollow portion defined between the second bevels of the opposing edges.

[0033] A second feature of the manufacturing process according to the invention includes that each opposite edge of the first and second bevels extends over a length corresponding to at least ten times the thickness of the component at the cut-out portion. Attached Figure Description

[0034] [ Figure 1 ] Figure 1 It is a 3D diagram of an aircraft engine, including the fan casing.

[0035] [ Figure 2 ] Figure 2 yes Figure 1 A half-view of the axial cross-section of the fan casing of the engine.

[0036] [ Figure 3 ] Figure 3 yes Figure 1 A partial perspective view of the fan housing shows a hollowed-out portion created in the fan housing according to an embodiment of the present invention.

[0037] [ Figure 4 ] Figure 4 yes Figure 3 The diagram shows a radial sectional view of the excavated portion along section plane IV.

[0038] [ Figure 5 ] Figure 5 yes Figure 3 The radial sectional view of the hollowed-out section shown illustrates the placement of the fiber preform of the filler within the hollowed-out section.

[0039] [ Figure 6 ] Figure 6 The diagram schematically illustrates the three-dimensional interlocking weave of a fiber preform component used to manufacture fillers.

[0040] [ Figure 7 ] Figure 7 It is a radial sectional view, showing the... Figure 3 The filler material present in the hollowed-out section shown.

[0041] [ Figure 8 ] Figure 8 It is a radial sectional view, showing the... Figure 3 The filler material present in the hollowed-out portion shown has fastening members.

[0042] [ Figure 9 The diagram schematically illustrates a three-dimensional interlocking weave for fabricating fillers in a single piece of fiber preform. Detailed Implementation

[0043] This invention is generally applicable to organic matrix composite components of any gas turbine.

[0044] The invention will be described below in conjunction with its application to the fan housing of a gas turbine engine for an aircraft.

[0045] For example in Figure 1 The engine shown in the diagram, from upstream to downstream, includes a fan 1, a compressor 2, a combustion chamber 3, a high-pressure turbine 4, and a low-pressure turbine 5 arranged at the engine inlet.

[0046] The engine is housed within a casing that includes several parts corresponding to different components of the engine. For example, the fan 1 is surrounded by a fan housing 10 having a rotating shape.

[0047] Figure 2The outline of the fan housing 10 (in the axial section) is shown, which is here made of an organic matrix composite material, i.e., made of fiber reinforcements such as carbon, glass, aramid, or ceramic, and densified by a polymer matrix such as epoxide, bismaleimide, or polyimide. The fiber reinforcements are made of strip-shaped fiber textures, which are obtained in a single piece by three-dimensional weaving, and the texture is formed by winding it onto a support tool. The fiber reinforcements thus formed are then densified by the matrix. The manufacture of such a housing is specifically described in US 8,322,971. The inner surface 11 of the housing defines the air inlet duct of the engine.

[0048] The shell 10, made of composite material (fiber reinforcement with matrix densification), has a rotational shape and is located in the axial direction D. A The housing extends in width between the downstream end 17 and the upstream end 18, while in the radial direction D R The housing 10 extends in thickness between the inner surface 11 and the outer surface 12. External flanges 14 and 15 may be provided at its upstream and downstream ends to allow for mounting and connection to other components. Between its upstream end 17 and downstream end 18, the housing 10 has a variable thickness, with a portion 16 of the housing having a greater thickness than the ends by gradually connecting to the ends. This portion 16 extends on either the upstream or downstream side of the fan location to form a retaining area capable of retaining debris, particles, or objects ingested at the engine inlet or radially ejected by fan rotation due to fan blade damage, thereby preventing them from penetrating the housing and damaging other components of the aircraft.

[0049] exist Figure 1 In this case, the housing 10 has a damaged area 20, such as that caused by blade debris thrown onto the inner surface 11 of the housing. According to the repair process of the invention, the housing is machined at the damaged area 20 to remove the affected composite material. The removal of the composite material is performed on a given surface of the housing, which at least covers the area identified as damaged and extends through the entire thickness of the housing. Figure 3 and Figure 4 As shown, a hollow portion 30 is obtained that simultaneously leads to the inner surface 11 and the outer surface 12 of the housing 10. In the example described herein, and according to specific features of the invention, the edges 31, 32, 33, and 34 of the hollow portion each include a corresponding first slope and a second slope, for example, the first slopes of edges 31 and 33 are respectively as follows: Figure 4 The inclined surfaces 310 and 330 shown, such as the second inclined surfaces of edges 31 and 33, are respectively as follows: Figure 4 The inclined planes 311 and 331 are shown. The hollowed-out portion 30 defines the free volume of the material 35, which will be occupied by the filler as described below.

[0050] Still according to the repair process of the present invention, the fiber preform of the filler to be placed within the volume defined by the hollowed-out portion 30 is made by three-dimensional weaving. In the example described herein, and as... Figure 5 As shown, the fiber preform 40 of the filler is composed of a first part 41 and a second part 42.

[0051] The three-dimensional weaving of the fiber preforms for the filler can be accomplished using interlocking weaving with multiple layers of warp and weft. Figure 6 An example of interlocking weaving of the first portion 41 of the fiber preform 40 of the filler is shown. Figure 6 In the cross-section, the weft yarns are interlocked. Three-dimensional interlocking weaving is a weaving in which each warp yarn with the same path is interlocked with multiple layers of weft yarns. The thickness can be gradually increased / decreased by adding / removing one or more layers of warp and weft yarns. The second part 42 of the fiber preform 40 of the filler can be made using the same weaving pattern.

[0052] Other three-dimensional weave patterns can be considered, such as multi-layered weaves with multi-satin or multi-ply weaves. This type of weave is described in document US2010 / 0144227.

[0053] The fiber preform of the filler is preferably woven from fibers that have the same properties as the fibers used to manufacture the fiber reinforcement of the shell.

[0054] Once the fiber preform 40 with filler is produced, it is placed in the free volume 35 defined by the hollowed-out portion 30.

[0055] The first portion 41 and the second portion 42 of the fiber preform 40 each have a geometry adapted to the portion of the free volume 35 to be filled. More specifically, in the example described herein, and as... Figure 5 As shown, the first portion 41 has a first inclined surface defined at the opposite edge ( Figure 5 The free volume 35 of the hollowed-out portion between the first slopes 310 and 330 of the edges 31 and 33 shown has a geometry complementary to that of the second slope defined at the opposite edges. Figure 5 The free volume 35 of the cutout portion 30 between the second inclined surfaces 311 and 331 of edges 31 and 33 shown has complementary geometry. Each opposing edge including the first and second inclined surfaces extends over a length corresponding to at least ten times the thickness of the shell at the cutout portion. For example, as Figure 4 and Figure 5 As shown, the extension lengths of edges 31 and 33 are respectively L 31 and L 33The length is at least the thickness E of the shell 10 at the hollowed-out portion 30. 10 This is ten times the value. This optimizes the transfer of mechanical loads to the bonding interface between the filler and the shell composite structure.

[0056] The fiber preform 40 of the filler is impregnated with a matrix precursor resin. The impregnation of the preform 40 can be performed before or after the fiber preform 40 of the filler is placed into the hollow portion 30. Preferably, a resin corresponding to the matrix precursor is selected, which has the same properties as the matrix used to densify the shell fiber reinforcement.

[0057] Then, for example, the resin is converted into a matrix by heat treatment to obtain, as Figure 7 The composite filler 50 shown comprises a 3D-woven fiber preform densified from a matrix, occupying a free volume defined by a cutout portion. The composite filler 50 includes a first portion 51 and a second portion 52. The first portion 51 has a geometry complementary to a portion of the volume of the cutout portion defined between first ramps 310 and 330 at opposing edges 31 and 33, while the second portion 52 has a geometry complementary to another portion of the volume of the cutout portion defined between second ramps 311 and 331 at opposing edges 31 and 32. The filler 50 is fully integrated into the housing structure. After the resin is converted into the matrix, the filler allows the composite material to adhere to the portion of the housing that contacts it; in this case, this portion is the first ramp and second ramp at each edge of the cutout portion. A binder can be further deposited on the bonding interface between the filler and the edges of the cutout portion to strengthen the bonding interface.

[0058] According to specific features of the invention, the mechanical strength of a component can be enhanced by integrating one or more fastening members into the filler, for example, Figure 8 The component 60 shown includes a screw 61 passing through the filler 50 and a tension nut 62 that mates with the free end of the screw 61. The fastening components (one or more) have no effect on the structure of the housing because they do not contact the housing but only the filler.

[0059] According to another specific feature of the invention, the first and second portions of the fiber preform of the filler can be joined together by weaving.

[0060] Figure 9 An example of interlocking weaving of the fiber preform 70 of the filler is shown, wherein the first part 71 and the second part 72 are joined together by weaving. Figure 9 In the cross-section, the weft yarn is in the middle. In this case, the deformability of the fiber preform 70 is used to insert it into the free volume defined by the hollowed-out portion.

[0061] This invention is also applicable to the rework of composite material shells.

[0062] In known methods, the production of composite shells begins with the formation of a fiber texture in the form of strips, achieved through three-dimensional weaving, such as "interlocking" weaving or one of the weaving methods described in document US 2010 / 0144227. The fiber structure can be woven from carbon fiber yarns, such as ceramic yarns made of silicon carbide, glass yarns, or aramid yarns.

[0063] A fiber reinforcement for the shell is formed by weaving fibers onto a mandrel with a profile corresponding to the contour of the shell to be manufactured. The fiber reinforcement constitutes a complete tubular fiber preform of the shell, forming a single piece. For this purpose, the mandrel has an outer surface whose profile corresponds to the inner surface of the shell to be produced, while the two flanges forming the components of the fiber preform correspond to the flanges of the shell.

[0064] The fiber reinforcement is then densified by a matrix. Densification of the fiber reinforcement involves filling the pores of the reinforcement with the material constituting the matrix throughout or in part of its volume. This matrix can be obtained in a manner known per se using liquid processing.

[0065] The liquid process involves impregnating a fiber reinforcement with a liquid composition containing an organic precursor of a matrix material. The organic precursor is typically in polymer form, such as a resin, and may optionally be diluted in a solvent. The fiber reinforcement is placed in a sealable mold having a housing with the final molded part shape. A liquid matrix precursor, such as a resin, is then injected into the entire housing to impregnate the entire fiber portion of the reinforcement.

[0066] The conversion of the precursor to an organic matrix, i.e., its polymerization, is carried out through heat treatment, typically by heating a mold. After removing any possible solvents and crosslinking the polymer, the reinforcement remains in the mold, which has a shape corresponding to the shape of the component to be produced. The organic matrix can be obtained, in particular, from epoxy resins such as commercially available high-performance epoxy resins, or from liquid precursors of carbon or ceramic matrices.

[0067] In the case of forming a carbon or ceramic matrix, heat treatment involves pyrolyzing an organic precursor to convert the organic matrix into a carbon or ceramic matrix, depending on the precursor used and the pyrolysis conditions. For example, the liquid carbon precursor can be a resin with a relatively high coke content, such as a phenolic resin, while the liquid ceramic precursor, particularly silicon carbide (SiC), can be a polycarbosilane (PCS), titanium-containing polycarbosilane (PTCS), or polysilazane (PSZ) resin. Several consecutive cycles from impregnation to heat treatment can be performed to achieve the desired degree of densification.

[0068] Densification of fiber reinforcements can be achieved using the well-known resin transfer molding (RTM) process. In the RTM process, the fiber reinforcement is placed in a mold having the shape of the shell to be produced. Thermosetting resin is injected into the internal space between the rigid material portion and the mold, which includes the fiber reinforcement. To control and optimize resin impregnation of the reinforcement, a pressure gradient is typically established within this internal space between the resin injection point and the resin discharge opening.

[0069] The resin used can be, for example, epoxy resin. Resins suitable for the RTM process are well known. They preferably have low viscosity to facilitate their injection into the fibers. The choice of the resin's temperature rating and / or chemical properties is determined based on the thermomechanical stresses the component must withstand. Once the resin is injected into the entire reinforcement, it is polymerized through heat treatment according to the RTM process.

[0070] After injection and polymerization, the part is demolded. Finally, the part is trimmed to remove excess resin, and the chamfers are machined to achieve the desired finish. Figure 1 and Figure 2 The shell 10 shown is a composite material shell.

[0071] At the end of the manufacturing process, the shell may have defects, such as one or more "dry" areas, corresponding to parts of the shell where the fiber reinforcement lacks matrix or does not contain sufficient matrix. In this case, the shell is inspected after manufacturing to detect one or more defective areas. If this is the case, the manufacturing process of the composite shell according to the invention further includes the following steps:

[0072] - The hollowed-out portion is created by removing the composite material from the defective areas, thereby forming a hollowed-out portion that extends through the entire thickness of the fiber reinforcement.

[0073] - Fiber preforms for three-dimensional braided fillers

[0074] - The fiber preforms of the filler are placed in the free volume of the shell defined by the hollowed-out portion.

[0075] - Before or after placing the fiber preform of the filler into the hollow section, impregnate the preform with a matrix resin precursor.

[0076] - Convert resin into a matrix to obtain a composite filler comprising a 3D woven fiber preform occupying a volume defined by a cutout portion.

[0077] The removal of the composite material is carried out on a given surface of the shell, which at least covers the non-conforming area of ​​the shell and the entire thickness of the shell. This results in a cutout extending to the inner and outer surfaces of the shell, for example... Figure 3 and Figure 4 The cutout portion 30 shown has a first bevel and a second bevel at its edges. As described below, the cutout portion defines the free volume of material intended to be occupied by the filler.

[0078] The fiber preforms of the filler are obtained through three-dimensional weaving and can be made from two different parts (e.g. Figure 5 The filler shown is either the first part 41 and the second part 42 of the fiber preform 40 or two parts woven together (e.g., Figure 9 The first part 71 and the second part 72 of the fiber preform 70 of the filler shown are formed.

[0079] The fiber preform of the filler is preferably woven from fibers with the same properties as the fibers used to manufacture the fiber reinforcement of the shell. The geometry of the first and second portions of the fiber preform of the filler is adapted to the portion of the free volume defined by the hollowed-out portion to be filled as described above.

[0080] Once the fiber preforms with fillers are produced, they are placed in the free volume defined by the cut-out portion.

[0081] The fiber preform of the filler is impregnated with a matrix precursor resin. Impregnation of the preform can be performed before or after placing the fiber preform of the filler into the hollowed-out portion. Preferably, a resin corresponding to the matrix precursor is selected, which has the same properties as the matrix used to densify the fiber reinforcement of the shell.

[0082] The resin is then converted into a matrix, for example, through heat treatment, to obtain a composite filler comprising a 3D-woven fiber preform densified from the matrix, such as... Figure 7 The composite material filler 50 shown occupies the free volume defined by the hollowed-out portion.

[0083] According to specific features of the invention, the mechanical strength of a component can be enhanced by integrating one or more fastening members into the filler, for example, as... Figure 8 The component 60 shown includes a screw 61 passing through the filler 50 and a tension nut 62 engaging with the free end of the screw 61. The fastening components (one or more) have no effect on the structure of the housing because they do not contact the housing but only the filler.

Claims

1. A gas turbine component made of a composite material, the component comprising a fiber reinforcement having a three-dimensional weave between a plurality of warp and a plurality of weft threads, the fiber reinforcement being densified by a matrix, the densified fiber reinforcement extending width between a downstream end and an upstream end in an axial direction, and extending thickness between an inner surface and an outer surface in a radial direction, the axial and radial directions being defined with reference to the axis of the component, wherein, The fiber reinforcement, densified by the matrix, includes at least one hollowed-out portion extending through the entire thickness of the fiber reinforcement, and wherein a composite filler is present in the free volume of the component defined by the at least one hollowed-out portion, the composite filler comprising a fiber preform with three-dimensional weave, the fiber preform being densified by the matrix, wherein each hollowed-out portion has at least two opposing edges, each including first and second ramps, the composite filler comprising a first portion and a second portion, the first portion having a geometry complementary to a portion of the volume of the hollowed-out portion defined between the first ramps of the opposing edges, and the second portion having a geometry complementary to another portion of the volume of the hollowed-out portion defined between the second ramps of the opposing edges.

2. A process for repairing a composite material component of a gas turbine, said component comprising a fiber reinforcement having a three-dimensional weave between a plurality of warp and a plurality of weft threads, said fiber reinforcement being densified by a matrix, wherein, in an axial direction, the densified fiber reinforcement extends a width between a downstream end and an upstream end, and in a radial direction, the densified fiber reinforcement extends a thickness between an inner surface and an outer surface, said axial and radial directions being defined with reference to the axis of said component, wherein, The process includes: - Identify at least one damaged area in the component. - The hollowed-out portion is created by removing the composite material at the damaged area, thereby forming a hollowed-out portion that extends through the entire thickness of the fiber reinforcement. - Fiber preforms for three-dimensional braided fillers - Place the fiber preform of the filler in the free volume defined by the hollowed-out portion of the component. - Before or after placing the fiber preform of the filler into the hollowed-out portion, the preform is impregnated with a matrix resin precursor. - The matrix resin precursor is polymerized into the matrix to obtain a composite filler comprising a 3D woven fiber preform occupying a volume defined by the cutout portion, wherein the manufacture of the cutout portion includes forming at least two opposing edges, each of the opposing edges including first and second ramps, the fiber preform of the filler comprising a first portion and a second portion, the first portion having a geometry complementary to a portion of the volume of the cutout portion defined between the first ramps of the opposing edges, and the second portion having a geometry complementary to another portion of the volume of the cutout portion defined between the second ramps of the opposing edges.

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