Method for manufacturing a fibrous preform comprising a tube preform part

Abstract

The invention relates to a method for manufacturing a fibrous preform, comprising the three-dimensional weaving of a fibrous blank (100) between a plurality of layers of warp yarns (101) and a plurality of layers of weft yarns (102), the fibrous blank (100) comprising first and second parts (130, 140) each having a flat shape extending in the transverse direction between lateral edges (135, 136, 145, 146) and in a thickness direction between first and second faces (133, 134, 143, 144). During the weaving of the lateral edges, warp yarns and weft yarns are gradually taken out from each of the first and second faces (133, 134, 143, 144) so as to form portions (1351, 1361, 1451, 1461, 1352, 1362, 1452, 1462) that are inclined with respect to the transverse direction in each of the lateral edges.

Description

[0001] Description

[0002] Title of the invention: Method for manufacturing a fibrous preform comprising a tube preform portion

[0003] Technical Field

[0004] The present invention relates to the field of fibrous preforms used to manufacture parts from composite materials. More particularly, it concerns the production of fibrous preforms for manufacturing composite parts that are tube-shaped or include a tube-shaped portion. Prior art

[0005] Tubular composite parts are used in the aerospace industry. For example, the new generation of unfaired engines (known as "open fan" or "open rotor") requires more compact blade roots. This need arises from the requirement to be able to rotate the blade around its vertical axis to adapt its angle of attack to the flight regime (variable-pitch blade). The blade root is formed from a tubular preform produced by three-dimensional weaving and incorporating an internal cavity. The preform is shaped by inserting a metal insert or sleeve into the internal cavity. An external metal shell is then attached to the outer surface of the preform.

[0006] Document EP 3733386 describes a process for manufacturing composite tubes in which the fibrous preform is produced by helical winding of fibrous ribbons around a mandrel. This process does not allow for the production of continuous fibrous reinforcements sufficient to give the tube adequate mechanical strength.

[0007] Another technique for forming tubular fiber preforms involves shaping textile layers around a forming element such as a mandrel. The textile layers are not bonded together. Each textile layer has a beveled edge at its ends, also known as a "scarf" zone. This beveled edge is designed to cooperate with another beveled edge at the other end of the same layer, or with a beveled edge of a different layer, to ensure continuity in the thickness of the formed tube preform.

[0008] However, when shaping textile layers into a tube geometry, the scarf-shaped edges remain difficult to control, primarily due to the limited deformation capacity of the textile layers at these edges. This results in irregularities in the thickness of the fiber preform and discontinuities at the junctions between the textile layers.

[0009] Description of the invention

[0010] It is therefore desirable to be able to propose a solution for the production of fibrous preforms that allows for a uniform thickness and continuity of material over the entire circumference of the tube preform portion. To this end, the present invention proposes a method for manufacturing a fibrous preform comprising at least one tube preform portion, the fibrous preform being intended to form the fibrous reinforcement of a part or part of a part made of composite material, the method comprising the three-dimensional weaving of a fibrous blank between a plurality of layers of warp yarns extending in a longitudinal direction and a plurality of layers of weft yarns extending in a transverse direction, the warp yarns being woven in a plurality of columns spaced apart from each other in the transverse direction.the fibrous blank comprising at least first and second parts of fibrous blank each having a flat shape extending along the longitudinal direction between a first free end and a second end, along the transverse direction between first and second lateral edges and along a thickness direction between first and second faces,

[0011] characterized in that, during the weaving of the first and second lateral edges respectively of the first and second parts of the fiber blank, warp yarns and weft yarns are progressively drawn out from each of the first and second faces so as to form in each of the first and second lateral edges first portions inclined with respect to the transverse direction and second portions inclined with respect to the transverse direction, the first and second inclined portions respectively of the first and second lateral edges of the first and second parts of the fiber blank joining at a free end of the lateral edge, and in that the process further comprises the tube-forming of the first and second parts of the fiber blank on a forming element,the second inclined portions of the first and second lateral edges of the first part of the fibrous blank and the first inclined portions of the first and second lateral edges of the second part of the fibrous blank being in contact with the conforming element while the first inclined portions of the first and second lateral edges of the first part of the fibrous blank cooperate respectively with the second inclined portions of the first and second lateral edges of the second part of the fibrous blank.

[0012] The formation of a double slanted portion (or double "scarf") on each of the lateral edges of the first and second fiber blanks greatly facilitates their tube forming. Indeed, a lateral edge with a double slanted portion deforms more easily than the same edge with a single slanted portion (or "scarf"), thus reducing the risk of buckling and stress on the fibers during tube forming of the fiber blanks.

[0013] Furthermore, with double-sloped lateral edges, alignment problems during the shaping of the fiber blank and problems maintaining their position during handling of the resulting preform are eliminated. This results in a tube preform section with a constant thickness and continuous fibrous material around its entire circumference.

[0014] According to another particular feature of the manufacturing process for a fibrous preform of the invention, an equal or different number of weft and warp yarns are drawn from each of the first and second faces of the first and second parts of the fibrous blank during the weaving of the first and second lateral edges of each of said first and second parts of the fibrous blank. It is thus possible to obtain an equal or different level of deformability in each of the inclined portions of a lateral edge. According to another particular feature of the manufacturing process for a fibrous preform of the invention, each weft yarn drawn from each of the first and second faces of the first and second parts of the fibrous blank is interlaced with at least one warp yarn before being drawn from said first and second parts of the fibrous blank.This improves the strength of the fibrous rough part during its deformation for shaping the preform.

[0015] According to another particular feature of the manufacturing process for a fibrous preform of the invention, the surface of the first and second inclined portions of the first and second lateral edges of the first and second parts of the fibrous blank, respectively, exhibits a higher bonding ratio than the core bonding ratio of said first and second inclined portions. This significantly reduces the presence of long floating fibers while improving the surface finish and strength of the inclined portions.

[0016] According to another particular feature of the manufacturing process of a fibrous preform of the invention, the fibrous preform corresponds to a preform of a blade or a propeller, the part of the tube preform corresponding to a part of the preform of the blade or propeller foot.

[0017] The invention also relates to a method for manufacturing a blade or propeller made of composite material comprising the manufacture of a fibrous preform according to the method for manufacturing a fibrous preform of the invention and the densification of said fibrous preform by a matrix.

[0018] The invention also relates to a fibrous preform manufactured according to the manufacturing process of a fibrous preform of the invention, the fibrous preform comprising at least a part of a tube preform.

[0019] The invention also relates to a blade or propeller made of composite material manufactured according to the manufacturing process of a blade or propeller of the invention. Brief description of the drawings

[0020] [Fig. 1] Figure 1 is a schematic view illustrating a fibrous blank for the manufacture of a fibrous preform according to an embodiment of the invention, [Fig. 2] Figure 2 is an enlarged cross-sectional view in the weft direction of a weave plane in the fibrous blank of Figure 1 along a section plane II-II,

[0021] [Fig. 3] Figure 3 is a schematic front view of a portion of fibrous rough in which the same number of weft and warp yarns are removed from each face of the portion of fibrous rough at its lateral edges,

[0022] [Fig. 4] Figure 4 is a schematic front view of a portion of fiber blank in which a different number of weft and warp yarns are removed from the faces of the portion of fiber blank at its lateral edges,

[0023] [Fig. 5] Figure 5 is a schematic perspective view showing the shaping of a portion of the foot of the fibrous blank of Figure 1,

[0024] [Fig. 6] Figure 6 is a schematic perspective view of a fibrous preform obtained by shaping the fibrous blank of Figure 1,

[0025] [Fig. 7] Figure 7 is an enlarged schematic front view of a portion of the foot preform of the fibrous preform of Figure 6.

[0026] Description of the implementation methods

[0027] The invention applies generally to the manufacture of fibrous preforms intended to form fibrous reinforcements for composite material parts corresponding to tubes or comprising a tube-shaped portion. The invention finds an advantageous, but not exclusive, application in the manufacture of blade roots or propellers for unfaired rotating wheels, such as those found in so-called "open rotor" aircraft engines.

[0028] In the following description, examples of embodiments are described in relation to the manufacture of a blade or propeller for unshod, rotating turbomachine wheels. However, these examples also apply to tubular parts or parts incorporating tubular components intended for other applications.

[0029] Figure 1 shows very schematically a fibrous blank 100 intended to form the fibrous preform of a blade to be produced. The fibrous blank 100 is obtained, as schematically illustrated in Figure 1, by three-dimensional (3D) weaving carried out in a known manner using a jacquard type loom on which a bundle of warp yarns 101 or strands has been arranged in a plurality of layers of several hundred yarns each, the warp yarns being linked by weft yarns 102.The fibrous blank 100 is woven in one piece, the blank comprising an aerodynamic profile part 110 extending in a longitudinal direction Di_, corresponding to the span direction of the blade to be manufactured, between a lower part 100c and an upper part 100d in a transverse direction DT, corresponding to the chord direction of the blade to be manufactured between a front edge 100a and a rear edge 100b, and in a thickness direction DE between two faces 110e and 110f intended to form respectively the extrados and intrados faces of the blade.

[0030] The fibrous blank 100 also includes a foot part 120 intended to subsequently form a blade foot and extending outside the aerodynamic profile part 110 from the lower part 100c the latter following the longitudinal direction and set back from the front and rear edges 100a and 100b following the transverse direction DT.

[0031] In the illustrated example, the 3D weave is an "interlock" weave. By "interlock" weave, we mean a weave structure in which each layer of weft yarns connects several layers of warp yarns, with all yarns in the same weft column having the same movement in the plane of the weave.

[0032] Other known three-dimensional weaving types may be used, such as those described in document US2007 / 007386. This document describes in particular the production by weaving in one piece of fibrous reinforcement structures for parts such as blades having a first type of core armor and a second type of skin armor which make it possible to confer both the mechanical and aerodynamic properties expected for this type of part.

[0033] The fibrous blank according to the invention can be woven in particular from carbon fiber yarns or ceramic such as silicon carbide.

[0034] As the airfoil section 110, whose thickness and width vary, is woven, a certain number of warp threads are not woven, which allows the desired contour and thickness to be defined, continuously varying, of the airfoil section 110. An example of evolving 3D weaving, allowing in particular the thickness of the blank to vary between a first edge intended to form the leading edge and a second edge of lesser thickness intended to form the trailing edge, is described in US document 2006 / 257260.

[0035] According to the invention, the weaving of the fiber blank 100 comprises the weaving of a first part of the fiber blank 130 and a second part of the fiber blank 140 superimposed along a thickness direction DE of the fiber blank and forming the foot part 120. The first part of the fiber blank 130 has a flat shape and extends along the longitudinal direction DL between a first free end 132 and a second end 133 connected to the aerodynamic profile part 110, along the transverse direction DT between first and second lateral edges 135 and 136, and along the thickness direction DE between first and second faces 133 and 134.Similarly, the second part of the fibrous blank 140 has a flat shape and extends along the longitudinal direction DL between a first free end 142 and a second end 143 connected to the aerodynamic profile part 110, along the transverse direction DT between first and second lateral edges 145 and 146, and along the thickness direction DE between first and second faces 143 and 144.

[0036] The first and second lateral edges 135, 136, 145, 146 respectively of the first and second parts of fibrous rough 130 and 140 each have a beveled shape. More specifically and in accordance with the invention, during the weaving of the first and second lateral edges 135 and 136 of the first part of the fibrous rough 130, warp yarns and weft yarns are progressively brought out from the first and second faces 133 and 134 so as to form, in the first lateral edge 135, first and second inclined portions 1351 and 1352 forming a non-zero angle with the transverse direction DT and joining at a free end 1350 of the first lateral edge 135 and, in the second lateral edge 136, first and second inclined portions 1361 and 1362 forming a non-zero angle with the transverse direction DT and joining at a free end 1360 of the second lateral edge 136.Similarly, during the weaving of the first and second lateral edges 145 and 146 of the second part of the fibrous rough 140, warp and weft yarns are progressively brought out from the first and second faces 143 and 144 so as to form, in the first lateral edge 145, first and second inclined portions 1451 and 1452 forming a non-zero angle with the transverse direction DT and joining at a free end 1450 of the first lateral edge 145 and, in the second lateral edge 146, first and second inclined portions 1461 and 1462 forming a non-zero angle with the transverse direction DT and joining at a free end 1460 of the second lateral edge 146.

[0037] Figure 2 illustrates the weave seen in warp section of the second lateral edge 146 of the second part of the fibrous rough 140 comprising the first and second inclined portions 1461 and 1462, the second part of the fibrous rough 140 comprising at the beginning of the second lateral edge 146 sixteen layers of warp yarns 101 (illustrated here in a single column) extending in the longitudinal direction Diet sixteen layers of weft yarns 102 extending in the transverse direction DT. As one approaches the free end 1460, weft yarn layers and warp yarn layers are removed from the second part of the fiber blank 140. More specifically, in the example described here, weft yarns FTS to FTU are progressively removed from the first face 143 of the second part of the fiber blank 140 and weft yarns FTI to FT? are progressively removed from the second face 144 of the second part of the fiber blank 140.As weft yarns are brought out of the second part of the fibrous rough 140, warp yarns 101 are also brought out of the latter so as to form a lateral edge with a decreasing thickness up to its free end.

[0038] Still in the example described here and according to a particular feature of the invention, each weft yarn FTI to FTU is interlaced with at least one warp yarn 101 before its exit from the second part of the fibrous rough 140. This makes it possible to improve the holding of the part of the fibrous rough during its deformation for the shaping of the preform as described below.

[0039] According to another particular feature of the invention, weft yarns belonging to a layer of weft yarns underlying the weft yarn layer located on the surface of the second fiber blank are removed from the second part of the fiber blank 140. By removing the weft yarns from a layer underlying the weft yarn layer located on the surface of the fiber structure, continuity of the weft yarn layers is ensured on the surface of the preform. This, in particular, prevents yarn misalignments, such as those that occur when yarns are systematically cut on the surface, leading, after densification, to the appearance of resin-rich areas that cause microcracking in the composite material. In an embodiment, weft yarns from the weft yarn layer located on the surface of the second part of the blank can be removed.In this case, the exit point of the weft yarns is preferably offset so that the yarns are caught by a yarn of the surface weave so that they are not cut at the previous binding point in order to avoid a lack of material.

[0040] The formation of the inclined portions 1351 and 1352 of the first lateral edge 135 of the first part of the fibrous rough 130, of the inclined portions 1361 and 1362 of the second lateral edge 136 of the first part of the fibrous rough 130 and of the inclined portions 1451 and 1452 of the first lateral edge 145 of the second part of the fibrous rough 140 can be carried out in the same way as that described above for the formation of the inclined portions 1461 and 1462 of the second lateral edge 146 of the second part of the fibrous rough 140.

[0041] The number of weft and warp yarns coming out from each of the faces 133, 134, 143, 144 of the first and second parts of the fibrous rough 130 and 140 during the weaving of the first and second lateral edges 135, 136, 145 and 146 of each of the said first and second parts of the fibrous rough may be the same or different.

[0042] Figure 3 illustrates an example in which the same number of weft and warp yarns are removed from each of the faces 143 and 144 of the second part of the fiber blank 140 at its lateral edges 145 and 146. In this example, each of the inclined portions 1451, 1452, 1461, and 1462 is formed by removing the same number of weft and warp yarns from each of the faces 143 and 144 at the first and second lateral edges 145 and 146, namely, weft yarns FT21 to FT27, FTU to FT20, FTS to FTI4, and FTI to FT?, respectively. As the weft yarns are removed, warp yarns are also removed to form lateral edges with decreasing thickness towards their free end.

[0043] Figure 4 illustrates another example of a second part of fibrous rough 140' in which a different number of weft and warp yarns are removed from each of the faces 143' and 144' of the second part of fibrous rough 140' at the lateral edges 145' and 146' thereof.More specifically, in this example, the inclined portions 1452' and 1461' formed respectively from the upper face 144' of the first lateral edge 145' and from the lower face 143' of the second lateral edge 146' are obtained by the exit of five weft yarns respectively FTS' to FTI2' and FTS' to FT' and by proportional exit of warp yarns while the inclined portions 1451' and 1462' formed respectively from the lower face 143' of the first lateral edge 145' and from the upper face 144' of the second lateral edge 146' are obtained by the exit of two weft yarns respectively FT-IS' and F™', and FTI' and FT2' and by proportional exit of warp yarns.In this case, inclined portions 1452' and 1461', comprising a greater number of weft and warp yarn exits than inclined portions 1451' and 1462', exhibit greater flexibility and, consequently, better deformability than inclined portions 1451' and 1462' for cylindrical shaping.

[0044] It is therefore possible to independently control the level of deformability of an inclined portion as a function of the number of warp and weft threads brought out during weaving.

[0045] Furthermore, the distance Ds between two successive weft thread exits (Figure 2) determines the degree of inclination of the slope formed by an inclined portion, that is, the value of the angle it forms with the transverse direction DT. Thus, the greater the distance Ds, the shallower the slope formed by the inclined portion, allowing for a longer length of the inclined portion. Conversely, the smaller the distance Ds, the steeper the slope formed by the inclined portion, allowing for a shorter length of the inclined portion.

[0046] According to another particular feature of the invention, the surface of the first and second inclined portions, respectively, of the first and second lateral edges of the first and second parts of the fiber blank may exhibit a binding ratio higher than the core binding ratio of said first and second inclined portions. Here, "binding ratio" refers to the frequency with which the weft yarns are interlaced with the warp yarns. Thus, a high binding ratio results in a tight weave, while a low binding ratio results in a loose weave.

[0047] The binding ratio can be increased on the surface of inclined sections by using a specific weave with a high binding ratio. Indeed, it is possible to modify the weave of inclined sections to obtain a higher binding ratio on their surface. As a non-limiting example, the surface of each inclined section can be woven in a plain weave pattern. This significantly reduces the presence of long floats while improving the surface finish and durability of the inclined sections.

[0048] Once the weaving is complete, the non-woven yarns surrounding the fiber blank 100 are cut to extract the blank, and then the foot portion of the blank is shaped. In the example described here, the shaping of the foot portion 120 is achieved by separating the first and second fiber blank sections 130 and 140 and inserting a shaping element 10 between these two sections. The shaping element 10 has a cylindrical or similar shape to allow the first and second fiber blank sections 130 and 140 to be shaped into a tube. The shaping element 10 can be made of a metallic material. Once the shaping element 10 is positioned, the first and second fiber blank sections 130 and 140 are shaped over the shaping element 10.More specifically, as illustrated in Figure 7, the first portion of the fibrous blank 130 is wound around a lower part of the shaping element 10, placing the second inclined portions 1352 and 1362 of the first and second lateral edges 135 and 136 in contact with the shaping element. Similarly, the second portion of the fibrous blank 140 is wound around an upper part of the shaping element 10, placing the first inclined portions 1451 and 1461 of the first and second lateral edges 145 and 146 in contact with the shaping element.As illustrated in Figure 7, the first inclined portion 1351 of the first lateral edge 135 of the first part of the fibrous rough 130 cooperates with the second inclined portion 1452 of the first lateral edge 145 of the second part of the fibrous rough 140 while the first inclined portion 1361 of the second lateral edge 136 of the first part of the fibrous rough 130 cooperates with the second inclined portion 1462 of the second lateral edge 146 of the second part of the fibrous rough 140.

[0049] This results in a fiber preform of blade 200 comprising a tube-shaped portion of the foot preform 220, which has a constant thickness around its entire circumference and without discontinuity at the junctions between the first and second portions of the fiber blanks (Figure 7). In the example described here, the fiber preform of blade 200 also includes a portion of the airfoil preform 210 extending along the longitudinal direction DL between a lower end 200c, from which the foot preform 220 extends, and a portion of the apex preform 200d; along the transverse direction DT between a leading edge portion 210a and a trailing edge portion 210b; and along the thickness direction DE between a portion of the front preform 200e and a portion of the second-face preform 200f.

[0050] The 200 blade's fibrous preform is then densified to obtain the final blade made of composite material. Densification is carried out using a well-known liquid-based process. This process involves impregnating the preform with a liquid composition containing a precursor of the matrix material. The precursor is usually a polymer, such as a high-performance epoxy resin, possibly diluted in a solvent. The preform is placed in a mold that can be sealed tightly, with a cavity shaped like the final molded blade. The mold is then closed, and the liquid matrix precursor (e.g., a resin) is injected into the entire cavity to impregnate the entire fibrous portion of the preform.The transformation of the precursor into a matrix, namely its polymerization, is carried out by heat treatment, generally by heating the mold, after removal of any solvent and crosslinking of the polymer, the preform always being kept in the mold having a shape corresponding to that of the part to be produced.

[0051] In the case of carbon or ceramic matrix formation, heat treatment consists of pyrolyzing the precursor to transform the matrix into a carbon or ceramic matrix, depending on the precursor used and the pyrolysis conditions. For example, liquid carbon precursors can be resins with relatively high coke content, such as phenolic resins, while liquid ceramic precursors, particularly SiC, can be polycarbosilane (PCS), polytitanocarbosilane (PTCS), or polysilazane (PSZ) type resins. Several consecutive cycles, from impregnation to heat treatment, can be carried out to achieve the desired degree of densification. Alternatively, an epoxy resin with a temperature class of 180 °C (maximum temperature withstood without loss of properties) can be used.The choice of temperature class and / or the chemical nature of the resin is determined according to the thermomechanical stresses to which the part must be subjected. The densification processes described above make it possible to produce, from the fibrous preform of the invention, primarily parts such as blades or propeller blades made of organic matrix composite (OMC), carbon matrix composite (C / C), and ceramic matrix composite (CMC).

[0052] In the example described here, the 200 blade fiber preform is intended for manufacturing a composite blade for unshod turbine wheels. In this case, the fiber preform may be a portion of a blade preform extending from a portion of a blade or propeller fiber preform. Also in the case of manufacturing a composite blade or propeller root for unshod turbine wheels, a metallic insert or internal sleeve is introduced into the internal housing of the tube preform. The insert may also be the cylindrical forming element, which in this case is made of a material compatible with the application of the part. Furthermore, an external shell, for example, made of metal, may be placed around the tube preform or the composite tube to allow the blade or propeller to be integrated into a rotor disk.The blade preform 200 thus formed is placed in an injection mold (not shown in Figure 6). A liquid matrix precursor is then injected into the porosity of the fibrous blade preform 200, namely into the porosity of the airfoil preform portion 210 and into the root preform portion 220. More precisely, the blade preform is placed in a mold that can be sealed tightly with a cavity shaped like the final molded part and which may, in particular, have a twisted shape corresponding to the final shape of the blade body. The mold is then closed, and the liquid matrix precursor, for example, a resin, is injected into the entire cavity to impregnate the entire fibrous portion of the assembly.

[0053] The transformation of the precursor into a matrix, namely its polymerization, is carried out by heat treatment, generally by heating the mold, after the removal of any solvent and crosslinking of the polymer. The preform remains in the mold, which has a shape corresponding to that of the blade. The matrix can be obtained, in particular, from epoxy resins, such as the high-performance epoxy resin sold under the reference PR 520 by CYTEC.

[0054] According to one aspect of the invention, the densification of the blade's fibrous preform can be achieved by the well-known resin transfer molding (RTM) process. In the RTM process, the fibrous preform is placed in a mold having the external shape of the blade. A thermosetting resin is injected into the internal space between the rigid material part and the mold, which includes the fibrous preform. A pressure gradient is generally established in this internal space between the point where the resin is injected and the resin's discharge ports in order to control and optimize the resin impregnation of the preform.

[0055] The resin used can be, for example, an epoxy resin. Resins suitable for RTM processes are well-known. They preferably have a low viscosity to facilitate their injection into the fibers. The choice of temperature class and / or the chemical nature of the resin is determined according to the thermomechanical stresses to which the part will be subjected. Once the resin has been injected throughout the reinforcement, it is polymerized by heat treatment according to the RTM process.

[0056] This results in a blade made of composite material comprising a tube-shaped foot whose fibrous reinforcement is formed by the foot preform part 220.

Claims

Demands

1. A method for manufacturing a fibrous preform (200) for a blade or propeller comprising at least one airfoil portion (210) and one tube preform portion (220), the fibrous preform being intended to form the fibrous reinforcement of a blade or propeller made of composite material, the method comprising the three-dimensional weaving of a fibrous blank (100) between a plurality of layers of warp yarns (101) extending along a longitudinal direction (DL) and a plurality of layers of weft yarns (102) extending along a transverse direction (DT), the warp yarns (101) being woven in a plurality of columns spaced apart along the transverse direction (DT), the fibrous blank (100) comprising at least one airfoil portion (110) and a foot portion (120) extending outside the airfoil portion, the foot part comprising first and second parts of fibrous rough-out (130,140) superimposed along a thickness direction (DE) and each having a flat shape extending along the longitudinal direction (DL) between a first free end and a second end (132, 131, 142, 141), along the transverse direction (DT) between first and second lateral edges (135, 136, 145, 146) and along a thickness direction (DE) between first and second faces (133, 134, 143, 144), characterized in that, during the weaving of the first and second lateral edges (135, 136, 145, 146) respectively of the first and second parts of the fibrous rough (130, 140), warp yarns and weft yarns (FT1-FT2?) are progressively drawn out from each of the first and second faces (133, 134, 143, 144) so ​​as to form in each of the first and second lateral edges (135, 136, 145, 146) first inclined portions (1351, 1361, 1451, 1461) with respect to the transverse direction (DT) and second inclined portions (1352, 1362, 1452, 1462) with respect to the transverse direction, the first and second inclined portions (1351, 1352, 1361, 1362, 1451, 1452, 1461, 1462) respectively of the first and second lateral edges (135, 136, 145, 146) of the first and second parts of the fibrous rudiment (130, 140) joining at a free end (1350, 1360, 1450, 1460) of the lateral edge,and in that the process further comprises tube-forming the first and second fibrous blank parts (130, 140) on a shaping element (10), the second inclined portions (1352, 1362) of the first and second lateral edges (135, 136) of the first fibrous blank part (130) and the first inclined portions (1451, 1461) of the first and second lateral edges (145, 146) of the second fibrous blank part (140) being in contact with the shaping element while the first inclined portions (1351, 1361) of the first and second lateral edges (135, 136) of the first fibrous blank part (130) cooperate respectively with the second inclined portions (1452, 1462) of the first and second lateral edges (145, 146) of the second part of the fibrous rough (140).,

2. A method according to claim 1, wherein an equivalent number of weft and warp yarns are drawn out from each of the first and second faces (133, 134, 143, 144) of the first and second fiber blank parts (130, 140) during the weaving of the first and second lateral edges (135, 136, 145, 146) of each of said first and second fiber blank parts.

3. A method according to claim 1, wherein a different number of weft and warp yarns are drawn out from each of the first and second faces (143', 144') of the first and second fiber blank parts (130, 140) during the weaving of the first and second lateral edges (135, 136, 145, 146) of each of said first and second fiber blank parts.

4. A method according to any one of claims 1 to 3, wherein each weft yarn (FT-I-FT-M) exiting from each of the first and second faces (143, 144) of the first and second fiber blank parts (130, 140) is interlaced with at least one warp yarn before exiting said first and second fiber blank parts.

5. A method according to any one of claims 1 to 4, wherein the surface of the first and second inclined portions (1351, 1352, 1361, 1362, 1451, 1452, 1461, 1462) respectively of the first and second lateral edges (135, 136, 145, 146) of the first and second fibrous blank parts (130, 140) has a bonding ratio higher than the core bonding ratio of said first and second inclined portions.

6. A method according to any one of claims 1 to 5, wherein the fibrous preform (200) corresponds to a preform of a blade or propeller, the portion of the tube preform corresponding to a portion of the blade or propeller foot preform.

7. Method of manufacturing a blade or propeller of composite material comprising manufacturing a fibrous preform according to any one of claims 1 to 6 and densifying said fibrous preform with a matrix.

8. Fibrous preform manufactured according to the process according to any one of claims 1 to 6, the fibrous preform comprising at least a tube preform portion.

9. Blade or propeller made of composite material manufactured according to the process of claim 7.

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