Method for manufacturing a fibrous blank for a fibrous preform of a tube made of composite material

Abstract

A method for manufacturing a fiber blank for a fiber preform of a composite tube. A method for manufacturing a fiber blank (100) comprising the three-dimensional weaving of first and second parts of the fiber blank (110, 120) between layers of warp yarns and layers of weft yarns. The method further comprises: - the joining of first lateral edges (113, 123) of the first and second parts of the fiber blank (110, 120) by first bonding weft yarns (TL1) woven with warp yarns present on said first lateral edges, - the joining of second lateral edges (114, 124) of the first and second parts of the fiber blank (110, 120) by second bonding weft yarns (TL2) woven with warp yarns present on said second lateral edges.The first and second fibrous blank parts (110, 120) together define an internal cavity (140) extending between the first and second lateral edges (113, 123, 114, 124) of said first and second fibrous blank parts. Figure for the abbreviation: Fig. 2.

Description

Title of the invention: Method for manufacturing a fibrous blank for a fibrous preform of a tube made of composite material. Technical field

[0001] The present invention relates to the field of fibrous blanks used to produce parts from composite materials. More particularly, it concerns the production of fibrous blanks for manufacturing tubes from composite materials. Previous technique

[0002] Tubular composite material parts are used in the aeronautical field. For example, the new generation of unfaired engines (known as "open fan" or "open rotor" engines) requires more compact blade roots. This need arises from the requirement to be able to rotate the blade around its vertical axis in order 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 having an internal recess. The preform is shaped by inserting a metallic insert or sleeve into the internal recess of the preform. An external metallic shell is then attached to the external surface of the preform.

[0003] Document EP 3 733 386 describes a method for manufacturing composite material tubes in which the fibrous preform is produced by helical winding of fibrous ribbons onto a mandrel. This method does not allow for the production of continuous fibrous reinforcements sufficient to give the tube adequate mechanical strength.

[0004] Another technique for forming a tubular fibrous preform consists of shaping textile layers around a forming element such as a mandrel. The textile layers are not bonded to each other. Each textile layer has a beveled edge at its ends, also called a "scarf" zone. The beveled edge is designed to cooperate with another beveled edge at the other end of the same layer or with a beveled edge of another layer in order to ensure continuity in the thickness of the formed tube preform.

[0005] However, during the shaping of the textile layer(s), controlling the positioning of the beveled edges relative to each other proves very difficult, both during the positioning of the textile layers and during the manipulation of the tube preform, making it impossible to ensure continuity between the ends of the layer(s). Furthermore, the textile layers tend to unravel at their ends due to the deformation imposed to form a tube. Description of the invention

[0006] It is therefore desirable to be able to propose a solution for the production of fibrous tube preforms which does not present the aforementioned disadvantages.

[0007] To this end, the present invention proposes a method for manufacturing a fibrous blank for a fibrous tube preform, the method comprising the production by three-dimensional weaving of first and second parts of the fibrous blank between a plurality of layers of warp yarns extending along a longitudinal direction and a plurality of layers of weft yarns extending along a transverse direction, the warp yarns being woven in a plurality of columns spaced apart along the transverse direction, the first and second parts of the fibrous blank each having a flat shape extending along the longitudinal direction between first and second longitudinal edges and along the transverse direction between first and second lateral edges, characterized in that the method further comprises: - the joining of the first lateral edges of the first and second parts of the fibrous rough by first weft binding yarns woven with warp yarns present on said first lateral edges of the first and second parts of the fibrous rough, - the joining of the second lateral edges of the first and second parts of the fibrous rough by second weft threads woven with warp threads present on said second lateral edges of the first and second parts of the fibrous rough, the first and second parts of fibrous rough-out together delimiting an internal housing extending between the first and second lateral edges of said first and second parts of fibrous rough-out.

[0008] The joining of the lateral edges of the first and second parts of the fiber blank by weft yarns woven with warp yarns present on said lateral edges greatly facilitates cooperation between the two parts of the fiber blank during its shaping. Indeed, the weft yarns form a hinge at the lateral edges of the parts of the fiber blank, which guides the coming together of the lateral edges precisely and repeatably during the shaping of the fiber blank. Problems of lateral edge alignment during the shaping of the fiber blank and of maintaining their position during handling of the resulting preform are thus eliminated. The risks of weave openings at the lateral edges during deformation and handling of the blank are also eliminated. Furthermore, fibrous wefts are also avoided because the bonding weft yarns allow the weave to be closed on these lateral edges.

[0009] According to a particular feature of the manufacturing process for a fiber blank of the invention, the first bonding weft yarns and weft yarns belonging to a top weft yarn layer are woven with warp yarns upstream of the first lateral edge of the first part of the fiber blank before they enter the first part of the fiber blank. This strengthens the fiber blank by preventing an opening in the weave at the level of the first bonding weft yarns, which are not woven directly with warp yarns within the thickness of the fiber blank upon their entry into said fiber blank. The first bonding weft yarns and the weft yarns belonging to the top weft yarn layer may also cross over each other upon their entry into the first part of the fiber blank in order to further strengthen the fiber blank.

[0010] According to another particular feature of the manufacturing process for a fiber blank of the invention, the second bonding weft yarns and weft yarns belonging to a lower weft yarn layer are woven with warp yarns downstream of the second lateral edge of the second part of the fiber blank after their exit from the second part of the fiber blank. This strengthens the fiber blank by preventing an opening in the weave at the level of the second bonding weft yarns, which are not woven directly with warp yarns within the thickness of the fiber blank upon their entry into said fiber blank. The second bonding weft yarns and the weft yarns belonging to the lower weft yarn layer may further cross over each other upon their exit from the second part of the fiber blank in order to further strengthen the fiber blank.

[0011] The invention also relates to a method for manufacturing a fibrous tube preform intended to form the fibrous reinforcement of a part or a portion of a part made of composite material, the method comprising:

[0012] - the production of a fibrous blank in accordance with the manufacturing process of a fibrous blank according to the invention,

[0013] - shaping the fibrous blank by separating the first and second parts of fibrous rough, the first lateral edges of the first and second parts of fibrous rough being folded against each other and the second lateral edges of the first and second parts of fibrous rough being folded against each other so as to form a part of tubular preform.

[0014] This yields a fibrous tube preform with a 3D weave and continuity along all internal and external cylindrical walls of the preform. It is therefore possible to manufacture fibrous preforms for composite material tubes that exhibit shape continuity even at the junctions between the lateral edges of the fibrous rough parts by means of a bond between these edges of the bonding weft threads as explained above.

[0015] According to a particular feature of the manufacturing process of a fibrous preform of the invention, the fibrous tube preform corresponds to a part of the foot preform of a blade or propeller.

[0016] The invention also relates to a method for manufacturing a tubular part in composite material comprising the manufacture of a fibrous tube preform according to the method for manufacturing a fibrous preform of the invention and the densification by a matrix of said fibrous tube preform.

[0017] The invention also relates to a fibrous blank for a fibrous tube preform comprising first and second parts of the fibrous blank, each having a three-dimensional weave between a plurality of warp yarn layers extending along a longitudinal direction and a plurality of weft yarn layers extending along a transverse direction, the warp yarns being arranged in a plurality of columns spaced apart along the transverse direction, the first and second parts of the fibrous blank each having a flat shape extending along the longitudinal direction between first and second longitudinal edges and along the transverse direction between first and second lateral edges, characterized in that the fibrous blank further comprises:

[0018] - first bonding weft yarns woven with warp yarns present on the first lateral edges of the first and second parts of the fibrous rough, the first bonding weft threads linking together the first lateral edges of the first and second parts of the fibrous rough,

[0019] - second bonding weft yarns woven with warp yarns present on the second lateral edges of the first and second parts of the fibrous rough, the second bonding weft threads linking together the second lateral edges of the first and second parts of the fibrous rough,

[0020] the first and second parts of the fibrous blank together delimiting an internal housing extending between the first and second lateral edges of said first and second parts of the fibrous blank.

[0021] The joining of the lateral edges of the first and second parts of the fiber blank by weft yarns woven with warp yarns present on said lateral edges greatly facilitates cooperation between the two parts of the fiber blank during its shaping. Indeed, the weft yarns form a hinge at the lateral edges of the parts of the fiber blank, which guides the coming together of the lateral edges precisely and repeatably during the shaping of the fiber blank. Problems of lateral edge alignment during the shaping of the fiber blank and of maintaining their position during the Manipulation of the resulting preform is thus eliminated. Furthermore, the risk of the weave opening at the lateral edges during deformation and manipulation of the fiber blank is also avoided because the bonding weft threads allow the weave to be closed at these lateral edges.

[0022] According to a particular feature of the fiber blank of the invention, it further comprises a first woven portion located upstream of the first lateral edge of the first part of the fiber blank, in which the first bonding weft yarns and weft yarns belonging to a top weft layer are woven with warp yarns. This strengthens the fiber blank by preventing the weave from opening at the level of the first bonding weft yarns, which are not woven directly with warp yarns within the thickness of the fiber blank upon their entry into said fiber blank. The first bonding weft yarns and the weft yarns belonging to the top weft layer may also cross over each other upon their entry into the first part of the fiber blank in order to further strengthen the fiber blank.

[0023] According to another particular feature of the fiber blank of the invention, it further comprises a second woven portion located downstream of the second lateral edge of the second part of the fiber blank, in which the second bonding weft yarns and weft yarns belonging to a lower weft yarn layer are woven with warp yarns. This strengthens the fiber blank by preventing an opening in the weave at the level of the second bonding weft yarns, which are not woven directly with warp yarns within the thickness of the fiber blank as they enter said fiber blank. The second bonding weft yarns and the weft yarns belonging to the lower weft yarn layer may also cross over each other as they exit the second part of the fiber blank in order to further strengthen the fiber blank.

[0024] The invention further relates to a tubular part made of composite material comprising a fibrous blank according to the invention densified by a matrix. Brief description of the drawings

[0025] [Fig-1] Fig. 1 is a schematic view illustrating a fibrous rough for the manufacture of a tube preform according to an embodiment of the invention,

[0026] [Fig.2] The [Fig.2] is a front view of the fibrous blank of the [Fig.1].

[0027] [Fig. 3] Fig. 3 is an enlarged cross-sectional view in grid direction of a plan of weaving armor in the fibrous blank of [Fig.1] according to a section plane III-III,

[0028] [Fig.4] The [Fig.4] is a schematic perspective view of a fibrous preform obtained by shaping the fibrous blank of [Fig.1],

[0029] [Fig.5] The [Fig.5] is a schematic perspective view of a tubular part obtained from the fibrous preform of the [Fig.4]. Description of the implementation methods

[0030] The invention applies generally to the manufacture of fibrous blanks intended to form fibrous preforms or parts of tube preforms forming reinforcements for composite material tubes. The invention finds an advantageous but not exclusive application in the manufacture of blade roots or propellers for unfaired rotating wheels such as in so-called "open rotor" aircraft engines.

[0031] In the following description, embodiment examples are described in relation to the manufacture of a blade or propeller for unshod, rotating turbomachine wheels. However, the embodiment examples also apply to tubular parts intended for other applications.

[0032] Fig. 1 shows very schematically a fibrous blank 100 intended to form the fibrous preform of a tube to be produced.

[0033] The fibrous blank 100 is obtained, as schematically illustrated in [Fig. 1], by three-dimensional (3D) weaving carried out in a known manner using a Jacquard-type loom (not shown in [Fig. 1]) on which a bundle of warp yarns 101 or strands is arranged in a plurality of layers extending along a longitudinal direction DL, the warp yarns being linked by weft yarns 102 belonging to layers of weft yarns extending along a transverse direction DT. The fibrous blank 100 is woven in a single piece and has a flat shape. The fibrous blank 100 extends in the longitudinal direction DL between first and second longitudinal ends 100a and 100b and along the transverse direction DT between first and second lateral ends 100c and 100d.

[0034] In the illustrated example, the 3D weave is an "interlock" weave. By "interlock" weave, we mean here a weave structure in which each layer of weft yarns connects several layers of warp yarns with all the yarns in the same weft column having the same movement in the plane of the weave.

[0035] Other known types of three-dimensional weaving may be used, such as those described in document WO 2006 / 136755.

[0036] The fibrous blank according to the invention can be woven in particular from carbon fiber yarns or ceramic such as silicon carbide.

[0037] According to the invention, the weaving of the fiber blank 100 comprises weaving a first portion of the fiber blank 110 and a second portion of the fiber blank 120 superimposed along a thickness direction DE of the fiber blank. The first portion of the fiber blank 110 has a flat shape and extends along the longitudinal direction DL between the first and second edges longitudinal 111 and 112 and along the transverse direction DT between the first and second lateral edges 113 and 114. Similarly, the second part of the fibrous rough 120 has a flat shape and extends along the longitudinal direction DL between the first and second longitudinal edges 121 and 122 and along the transverse direction Dt between the first and second lateral edges 123 and 124.The first longitudinal edges 111 and 121, on the one hand, and the second longitudinal edges 112 and 122, on the other hand, of the first and second parts of the fibrous blank 110 and 120 correspond respectively to the first and second longitudinal ends 100a and 110b of the fibrous blank 100 while the first lateral edges 113 and 123, on the one hand, and the second lateral edges 114 and 124, on the other hand, of the first and second parts of the fibrous blank 110 and 120 correspond respectively to the first and second lateral ends 100c and 100d of the fibrous blank 100.

[0038] In the example described here, the first lateral edges 113 and 123 of the first and second fiber blanks 110 and 120, respectively, each have a beveled shape. Similarly, the second lateral edges 114 and 124 of the first and second fiber blanks 110 and 120, respectively, each have a beveled shape. As described in detail below, the first lateral edges 113 and 123, as well as the second lateral edges 114 and 124, are intended to cooperate with each other during the shaping of the fiber blank. The complementary bevel shape of the first lateral edges 113 and 123, on the one hand, and of the second lateral edges 114 and 124, on the other hand, facilitates the edge-to-edge positioning of the first and second parts of fibrous rough 110 and 120 as well as their binding by weft threads as explained below in detail.

[0039] The first and second fiber blank parts 110 and 120 are separated from each other by a debonding 103 formed within the fiber blank 100 between two successive layers of warp yarns. The debonding 103 extends along a plane parallel to the surface of the fiber blank and over a debonding zone delimited by a contour 103a separating the fiber blank 100 into two fiber blank parts 110 and 120.

[0040] The debonding 103 extends over the entire fibrous blank along the longitudinal direction DL so as to open at the longitudinal ends 100a and 100b. Furthermore, and in accordance with the invention, the debonding 103 extends in the transverse direction DT between first and second debonding surfaces 103b and 103c, the first debonding surface 103b corresponding to a first bonding portion 105 between the first lateral edges 113 and 123 respectively of the first and second fibrous blank portions 110 and 120, the second debonding surface 103c corresponding to a second bonding portion 107 between the second edges lateral 114 and 124 respectively of the first and second parts of the fibrous blank 110 and 120 (i.e. that the debonding 103 does not open onto the first and second lateral ends 100c and 100d of the fibrous blank 100). The debonding 103 thus forms in the fibrous blank 100 an internal housing 140 which opens onto the longitudinal ends 100a and 100b of said blank.

[0041] Still in accordance with the invention and as illustrated in [Fig.2], the first bonding portion 105 between the first lateral edges 113 and 123 respectively of the first and second fibrous blank parts 110 and 120 is made by first bonding weft yarns TLi woven with warp yarns from the plurality of layers of warp yarns present at the edge of the first lateral end 100c of the fibrous blank 100 comprising warp yarns present on the first lateral edges of the first and second fibrous blank parts.Similarly, the second bonding portion 107 between the second lateral edges 114 and 124 respectively of the first and second fibrous rough parts 110 and 120 is made by second bonding weft yarns TL 2 woven with warp yarns from the plurality of layers of warp yarns present at the edge of the second lateral end lOOd of the fibrous rough 100 comprising warp yarns present on the second lateral edges of the first and second fibrous rough parts.

[0042] An example of a 3D interlock weave of the fiber blank 100 is shown schematically in [Fig. 3]. [Fig. 3] is a partial enlarged view of a weft cross-section, also called the weft plane, which shows the path of the weft yarns relative to the warp yarns (shown in cross-section) in the fiber blank 100 (section ni-III in [Fig. 1]). In this example, the fiber blank 100 comprises twelve layers Ci to Ci2 of warp yarns 101 extending substantially in the longitudinal direction DL. The warp yarns 101 are woven in a plurality of columns spaced apart along the transverse direction DT.

[0043] In [Fig.3], the six warp layers Ci to C6 are linked by weft yarns T12, T3, T4, T5 and T6 to form the first part of the fiber blank 110 while the six warp yarn layers C7 to Ci2 are linked by weft yarns T7, T8, T9, T10 and TLi to form the first part of the fiber blank 120. With the exception of the path of the weft yarn TLi on the first lateral edges 113 and 123 respectively of the first and second parts of the fiber blank 110 and 120 and of the weft yarn TL2 on the second lateral edges 114 and 124 respectively of the first and second parts of the fiber blank 110 and 120, the weft yarns extend substantially in the transverse direction DT.

[0044] The fact that the weft yarns TL2, T3, T4, T5 and T6 do not extend into the warp yarn layers C7 to Ci 2 of the first part of the fibrous rough 120 and that the yarns weft T7, T8, T9, Ti0 and Tu do not extend into the warp yarn layers Ci to C6 of the first part of fibrous rough 110 ensures the unbinding 103 which separates the first and second parts of fibrous rough 110 and 120.

[0045] The connection between the first lateral edges 113 and 123 of the first and second parts of the fiber blank 110 and 120 forming the first portion of the connection 105 is made with first weft connecting yarns TL1 (only one of them being shown in [Fig.3]) which are woven with warp yarns present on said first lateral edges 113 and 123 of the first and second parts of the fiber blank 110 and 120. In the example described here, the first weft connecting yarns TL1 are woven with the first warp yarns of each layer of warp yarns C^C12.The first bonding weft yarns TL1 can also be woven with several warp yarns from each layer of warp yarns Ci to Ci2 present at the edge of the first lateral edges 113 and 123 of the first and second parts of the fiber blank 110 and 120, such as for example the first and second warp yarns of the layers of warp yarns Ci to Ci2 present from the first lateral end 100c of the fiber blank 100. The first bonding weft yarns TL1 are then woven with warp yarns belonging to the second part of the fiber blank 120, in the example described here with the warp yarns of the layers of warp yarns Cn and Ci2.

[0046] The connection between the first lateral edges 114 and 124 of the first and second parts of the fiber blank 110 and 120 forming the second portion of the connection 107 is made with second connecting weft yarns TL2 (only one of them being shown in [Fig.3]) which are woven with warp yarns present on said first lateral edges 114 and 124 of the first and second parts of the fiber blank 110 and 120. In the example described here, the second connecting weft yarns Tl2 are woven with the last warp yarns of each layer of warp yarns Ci to C12.The second bonding weft yarns TL2 can also be woven with several warp yarns from each layer of warp yarns Ci to Ci2 present at the end of the second lateral edges 114 and 124 of the first and second fiber blank parts 110 and 120, such as for example the penultimate and last warp yarns of the layers of warp yarns Ci to Ci2 present on the second lateral end 100 of the fiber blank 100. The second bonding weft yarns TL2 are then woven with warp yarns belonging to the first part of the fiber blank 110, in the example described here with the warp yarns of the layers of warp yarns Ci and C2.

[0047] According to a particular feature of the invention illustrated in [Fig. 3], the first bonding weft yarns TLi and weft yarns belonging to a layer of upper weft yarn, in the example described here the second bonding weft yarns TL2, are woven with warp yarns upstream of the first lateral edge 113 of the first part of the fiber blank 110 before their entry into said first part of the fiber blank 110 so as to form a first woven portion 108. This makes it possible to strengthen the strength of the fiber blank by avoiding an opening of the weave at the level of the first bonding weft yarns TLi which are not woven directly with warp yarns in the thickness of the fiber blank 100 when they enter said fiber blank. The first bonding weft yarns TLi and the weft yarns belonging to the upper weft yarn layer, here the second bonding weft yarns TL 2, preferably cross when they enter the first part of the fiber rough 110, which further strengthens the weave's stability in the fiber rough 100.When the second bonding weft yarns TL2 do not extend to the first lateral edge 113 of the first part of the fiber blank 100, the first bonding weft yarns are woven with weft yarns belonging to another layer of upper weft yarn, such as the weft yarns T3 in the example described here.

[0048] According to another particular feature of the invention illustrated in [Fig.3], the second bonding weft yarns TL2 and weft yarns belonging to a lower weft yarn layer, in the example described here the first bonding weft yarns TLb are woven with warp yarns downstream of the second lateral edge 124 of the second part of the fiber blank 120 after their exit from said second part of the fiber blank 120. This makes it possible to strengthen the strength of the fiber blank by avoiding an opening of the weave at the level of the second bonding weft yarns TL2 which are not woven directly with warp yarns in the thickness of the fiber blank 100 when they enter said fiber blank.The second bonding weft yarns TL 2 and the weft yarns belonging to the lower weft yarn layer, here the first bonding weft yarns TL b, preferably cross over each other when they exit the second part of the fiber blank 120, which further strengthens the weave's strength in the fiber blank 100. When the first bonding weft yarns TL i do not extend to the second lateral edge 124 of the second part of the fiber blank 100, the second bonding weft yarns are woven with weft yarns belonging to another lower weft yarn layer, such as the weft yarns Tiodans in the example described here.

[0049] Once the weaving is finished, the non-woven yarns present around the fibrous blank 100 are cut to extract the blank and then the foot part of the blank is shaped.

[0050] As illustrated in Figures 2 and 4, the shaping of a portion of the tubular preform is carried out by separating the first and second portions of the fiber blank 110 and 120 from the fiber blank 100, which results, on the one hand, in the approach along a direction indicated by the arrow SP1 on [Fig.2] of the first lateral edges 113 and 123 and, on the other hand, in the approach along a direction indicated by the arrow SP2 on [Fig.2] of the second lateral edges 114 and 124. The bonding weft yarns TLi and TL2 form hinges respectively between the first lateral edges 113 and 123 and the second lateral edges 114 and 124 of the portions of the fiber blank 110 and 120 which guide the approach of the lateral edges precisely and repeatably during the shaping of the fiber blank.

[0051] Once the fiber blank 100 is fully shaped as illustrated in [Fig. 4], the first lateral edges 113 and 123 and the second lateral edges 114 and 124 are folded against each other, respectively. The shaping of the fiber blank can be achieved by inserting a cylindrical forming element into the internal cavity 140 formed by the debonding 103 in the fiber blank 100 (not shown in [Fig. 4]). The cylindrical forming element can, in particular, be made of metallic material or resin, for example, by additive manufacturing. The cylindrical forming element can also be made of a flexible material. The cylindrical forming element can also be made of a fusible material to form a hollow cylinder after consolidation.

[0052] As shown in [Fig. 4], a fibrous tube preform 200 is obtained, exhibiting a 3D weave with continuity along all the internal and external cylindrical walls of the preform. It is thus possible to manufacture fibrous preforms for composite material tubes that maintain a continuous shape even at the junctions between the lateral edges of the fiber blanks, thanks to the bonding of these edges by the weft threads as explained above.

[0053] The fibrous preform 200 is then densified to obtain the final part, here a tube 300 made of composite material, as illustrated in [Fig. 5]. The densification is carried out in a manner known per se, using the liquid process. The liquid process consists of impregnating the preform with a liquid composition containing a precursor of the matrix material. The precursor is usually in the form of 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 having the shape of the final molded tube. 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 preform.

[0054] 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.

[0055] In the case of forming a carbon or ceramic matrix, the 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 a 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. An epoxy resin with a temperature class of 180 °C (maximum temperature withstood without loss of properties) can also be used.The choice of temperature class and / or chemical nature of the resin is determined according to the thermomechanical stresses to which the part must be subjected.

[0056] The densification processes described above make it possible to produce, from the fibrous preform of the invention, mainly parts such as blades or propeller blades in organic matrix composite material (CMO), carbon matrix (C / C) and ceramic matrix (CMC).

[0057] In the example described here, the fibrous tube preform 200 is intended for manufacturing a blade or propeller root made of composite material for unshod turbine wheels of a turbomachine. In this case, the fibrous preform may be a portion of a root preform located in the extension of a portion of a blade preform of a fibrous blade or propeller preform. Also in the case of manufacturing a blade or propeller root made of composite material for unshod turbine wheels of a turbomachine, 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.In addition, an external shell, for example made of metal, can be placed around the tube preform or the composite material tube to allow the integration of the blade or propeller into a rotor disc.

Claims

Demands

1. A method for manufacturing a fibrous blank (100) for a fibrous tube preform, the method comprising producing, by three-dimensional weaving, first and second parts of a fibrous blank (110, 120) 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 first and second parts of a fibrous blank (110, 120) each having a flat shape extending along the longitudinal direction (DL) between first and second longitudinal edges (111, 112, 121, 122) and along the transverse direction (DT) between first and second lateral edges (113, 123, 114, 124),characterized in that the process further comprises: - joining the first lateral edges (113, 123) of the first and second fiber blanks (110, 120) by first bonding weft yarns (TL1) woven with warp yarns present on said first lateral edges of the first and second fiber blanks, - joining the second lateral edges (114, 124) of the first and second fiber blanks (110, 120) by second bonding weft yarns (TL2) woven with warp yarns present on said second lateral edges of the first and second fiber blanks, the first and second fiber blanks (110, 120) together defining an internal cavity (140) extending between the first and second lateral edges (113, 123, 114, 124) of said first and second blanks of fibrous rough material.

2. A method according to claim 1, wherein the first bonding weft yarns (TL1) and weft yarns (TL2) belonging to an upper weft yarn layer are woven with warp yarns upstream of the first lateral edge (113) of the first fibrous rough part (110) before their entry into said first fibrous rough part.

3. Method according to claim 2, wherein the first bonding weft yarns (TL1) and the weft yarns (TL2) belonging to the upper weft yarn layer cross over each other upon entering the first part of the fibrous rough (110).

4. A method according to any one of claims 1 to 3, wherein the second bonding weft yarns (TL2) and weft yarns (TLi) belonging to a lower weft yarn layer are woven with warp yarns downstream of the second lateral edge (124) of the second fibrous rough part (120) after their exit from said second fibrous rough part.

5. Method according to claim 4, wherein the second bonding weft yarns (TL2) and the weft yarns (TLi) belonging to the lower weft yarn layer cross over each other as they exit the second part of the fibrous rough (120).

6. Method of manufacturing a fibrous tube preform (200) intended to form the fibrous reinforcement of a part or part of a part made of composite material, the method comprising: - the production of a fibrous blank (100) according to the method according to any one of claims 1 to 5, - the shaping of the fibrous blank (100) by separating the first and second parts of the fibrous blank (110, 120), the first lateral edges (113, 123) of the first and second parts of the fibrous blank being folded against each other and the second lateral edges (114, 124) of the first and second parts of the fibrous blank being folded against each other so as to form a part of the tubular preform (200).

7. Method according to claim 6, wherein the fibrous tube preform (200) corresponds to a part of the foot preform of a blade or propeller.

8. Method of manufacturing a tubular part of composite material comprising manufacturing a fibrous tube preform (200) according to claim 6 or 7 and densifying said fibrous tube preform with a matrix.

9. A fibrous blank (100) for a fibrous tube preform comprising first and second parts of a fibrous blank (110, 120), each having a three-dimensional weave between a plurality of layers of warp yarns (101) extending along a direction longitudinal (DL) and a plurality of weft yarn layers (102) extending along a transverse direction (DT), the warp yarns (101) being arranged in a plurality of columns spaced apart along the transverse direction (DT), the first and second fiber blank parts (110, 120) each having a flat shape extending along the longitudinal direction (DL) between first and second longitudinal edges (111, 112, 121), 122 and along the transverse direction (DT) between first and second lateral edges (113, 123, 114, 124), characterized in that the fiber blank further comprises: - first bonding weft yarns (TLi) woven with warp yarns present on the first lateral edges (113, 123) of the first and second fiber blank parts (110, 120), the first bonding weft yarns linking together the first lateral edges of the first and second parts of the fibrous rough-out,- second bonding weft yarns (TL2) woven with warp yarns present on the second lateral edges (114, 124) of the first and second fiber blank parts (110, 120), the second bonding weft yarns linking together the second lateral edges of the first and second fiber blank parts, the first and second fiber blank parts (110, 120) together delimiting an internal housing (140) extending between the first and second lateral edges (113, 123, 114, 124) of said first and second fiber blank parts.

10. A blank according to claim 9, further comprising a first woven portion (108) present upstream of the first lateral edge (113) of the first fibrous blank portion (110) and in which the first bonding weft yarns (TL1) and weft yarns (TL2) belonging to an upper weft yarn layer are woven with warp yarns.

11. A blank according to claim 10, wherein the first bonding weft yarns (TL1) and the weft yarns (TL2) belonging to the upper weft yarn layer cross over each other upon entering the first fibrous blank portion (110).

12. A blank according to any one of claims 9 to 11, further comprising a second woven portion (109) located downstream of the second lateral edge (124) of the second blank portion fibrous (120) and in which the second bonding weft yarns (Tl2) and weft yarns (TLi) belonging to a lower weft yarn layer are woven with warp yarns.

13. A blank according to claim 12, wherein the second bonding weft yarns (TL2) and the weft yarns (TLi) belonging to the lower weft yarn layer cross over each other as they exit the second part of the fibrous blank.

14. Tubular part in composite material (300) comprising a fibrous blank (100) according to any one of claims 9 to 13 densified by a matrix.

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