Fibrous texture for composite material casing with local adaptation of elongation at break

Abstract

Fibrous texture for a casing made of composite material with local adaptation of the elongation at break A fibrous texture (100) having a three-dimensional weave between a plurality of layers of warp threads extending in a longitudinal direction (X) and a plurality of weft layers extending in a lateral direction (Y), the warp threads and the majority of the weft threads being made of a first type of fibers, the fibrous texture further comprising a first portion (P1) and a second portion (P2). The second portion (P2) comprises a zone with increased elongation (ZA) extending over a width (lZA) determined in the lateral direction (Y) and set back from the first and second lateral edges (101, 102) of the fibrous texture.The increased elongation zone (ZA) comprises weft yarns made of the first type of fibers and weft yarns made of a second type of fibers having a second elongation at break greater than the first type of fibers, the weft yarns present in the areas of the second portion located outside said at least one increased elongation zone being made of the first type of fibers. Figure for abstract: Fig. 2.

Description

Title of the invention: Fibrous texture for a composite material casing with local adaptation of the elongation at break Technical field

[0001] The present invention relates to a fibrous texture which can be used, in particular but not exclusively, to form the fibrous reinforcement of an aeronautical engine fan casing made of composite material. Prior art

[0002] The manufacture of a casing made of composite material begins with the production of a fibrous texture in the form of a strip, the fibrous texture being produced by three-dimensional weaving between a plurality of layers of warp threads and a plurality of layers of weft threads. The fibrous texture thus obtained is wound over several turns on a mold or tool having the shape of the casing to be produced and held between the mold and segments forming a counter-mold so as to obtain a fibrous preform.

[0003] Once the fiber preform has been produced, that is to say at the end of the winding of the fiber texture, the tooling carrying the fiber preform is closed by counter-molds then transported to an oven or furnace in which the densification of the preform by a matrix is ​​carried out, the matrix being able to be obtained in particular by injection and polymerization of a resin in the fiber preform.

[0004] A fan housing serves three main functions, namely:

[0005] - ensure the connection of engine parts to each other,

[0006] - define the air inlet vein in the engine,

[0007] - provide retention by retaining ingested debris inside the engine, or blades or blade fragments projected by centrifugation, in order to prevent them from passing through the casing and reaching other parts of the aircraft.

[0008] The first two functions are not very demanding in terms of mechanical properties but are permanently active. On the other hand, the third function, even if it is very little used, is very demanding in terms of mechanical properties. In the case of a blade breakage, it fragments on contact with the casing. Three types of stresses can then occur:

[0009] - A perforating impact, very localized, generally at the right of the axial position of the dawn. It causes perforation on the internal face and high local deformations on the external face;

[0010] - A non-perforating, relatively localized impact can occur downstream (and / or upstream) of the axial position of the blade. This impact causes local deformations raised on the internal and external faces;

[0011] - An extended wave of displacement / deformation that initiates from impacts main ones, then spreads from one point to another in the casing.

[0012] To resist a perforating impact, one solution is a localized thickening in the area of ​​this impact.

[0013] To resist a non-perforating impact, one solution is a better elongation at break in the area of ​​this impact.

[0014] To resist a wave of deformation, local (or global) stiffening can be a solution.

[0015] Regarding the improvement of impact resistance, document US2021164364 discloses the manufacture of a fibrous texture which makes it possible to improve the shear resistance of a casing by the use of fiberglass yarns among the carbon fiber yarns in the fibrous texture. However, the use of fiberglass yarns reduces the overall stiffness of the casing and, consequently, its resistance to a displacement / deformation wave.

[0016] Thus, there is a need to improve the resistance to a non-perforating impact of a composite material casing while ensuring good resistance to a displacement / deformation wave. Statement of the invention

[0017] To this end, the invention proposes a fibrous texture having a strip shape comprising an inner face and an outer face, the fibrous texture extending in a longitudinal direction over a determined length between a proximal portion and a distal portion and in a lateral direction over a determined width between a first lateral edge and a second lateral edge, the fibrous texture having a three-dimensional weave between a plurality of layers of warp threads extending in the longitudinal direction and a plurality of weft layers extending in the lateral direction, the warp threads and the majority of the weft threads being made up of a first type of fibers having a first elongation at break,the fibrous texture further comprising a first portion extending in the longitudinal direction over a determined length from the proximal part and a second portion extending in the longitudinal direction over a determined length between the first portion and the distal part of said fibrous texture,

[0018] characterized in that the second portion comprises at least one zone with increased elongation extending over a determined width in the lateral direction and set back from the first and second lateral edges and in that said at least one zone with increased elongation comprises weft threads made of the first type of fibers and weft threads made of a second type of fibers having a second elongation at break greater than the first elongation at break, the weft threads present in the areas of the second portion located outside the area(s) with increased elongation being made of the first type of fibers.

[0019] The fibrous texture is intended to be wound in several turns in order to form a fibrous reinforcement of a casing made of composite material. The first portion is intended to form the radially internal part of this fibrous reinforcement (first turn(s) of the winding). The second portion is intended to form the radially external part of this fibrous reinforcement (last turn(s) of the winding).

[0020] The inventors have found that it is possible to locally improve the resistance of the casing to non-perforating impact, for example with a detached blade, by judicious placement of wires or strands made up of a second type of fibers having an elongation at break greater than the elongation at break of the other wires or strands of the fibrous texture which are made up of a first type of fibers.

[0021] The other layers of warp and weft yarns or strands in the first portion but also in the zones of the second portion located outside the zone(s) with increased elongation are made up of yarns or strands of the first type of fiber which has an elongation at break lower than that of the second type of fiber in order to maintain good rigidity in the first and second portions.

[0022] The fibrous texture of the invention therefore comprises one or more zones with increased elongation, the length of which in the direction of the warp threads and the width of which in the direction of the weft threads can be perfectly delimited in the fibrous texture. This makes it possible to form a casing made of composite material with one or more zones having particular mechanical properties making it possible to improve the resistance to a non-perforating impact, without modifying the mechanical properties of the other parts of the casing. The fibrous texture of the invention therefore makes it possible to produce casings made of composite material having improved resistance to a non-perforating impact while retaining good resistance to a displacement / deformation wave.

[0023] According to a characteristic of the fibrous texture of the invention, weft threads present in the zone(s) with increased elongation on the side of the external face of the fibrous texture are made of the second type of fibers, the weft threads present in the zone(s) with increased elongation present on the side of the internal face of the fibrous texture being made of the first type of fibers. The insertion of weft threads made of the second type of fibers on the external face of the fibrous texture makes it possible to minimize the appearance of cracks in a casing using the fibrous texture as fibrous reinforcement because the tensile forces are mainly exerted on the external face.

[0024] According to another characteristic of the fibrous texture of the invention, the quantity of threads of weft made up of the second type of fibers present in the zone(s) with increased elongation is between 10% and 50% of the number of weft threads present in the zone(s) with increased elongation.

[0025] According to one embodiment of the fibrous texture of the invention, the second portion of the fibrous texture comprises a number of layers of warp threads and layers of weft threads similar to the number of layers of warp threads and layers of weft threads of the first portion of said fibrous texture.

[0026] According to another embodiment of the fibrous texture of the invention, the zone(s) with increased elongation in the second portion of the fibrous texture comprise a number of layers of warp threads and layers of weft threads greater than the number of layers of warp threads and layers of weft threads of the other parts of the second portion and of the first portion of said fibrous texture.

[0027] The invention also relates to a fibrous preform for an aeronautical casing comprising a winding over several turns of a fibrous texture according to the invention, the first portion being located on the side of a radially internal face of the preform, and the second portion being located on the side of a radially external face of the preform.

[0028] The invention also relates to a gas turbine casing made of a composite material, comprising a fibrous reinforcement consisting of a fibrous preform according to the invention, and a matrix densifying the fibrous reinforcement. The casing may in particular be a gas turbine fan casing.

[0029] The invention also relates to an aeronautical gas turbine engine having a casing according to the invention.

[0030] The invention also relates to a method for manufacturing a fibrous texture by three-dimensional weaving between a plurality of layers of warp threads extending in a longitudinal direction and a plurality of layers of weft threads extending in the lateral direction, the warp threads and the majority of the weft threads being made of a first type of fibers having a first elongation at break, the fibrous texture having a strip shape comprising an internal face and an external face, the fibrous texture extending in the longitudinal direction over a determined length between a proximal part and a distal part and in the lateral direction over a determined width between a first lateral edge and a second lateral edge,the method comprising weaving a first portion extending in the longitudinal direction over a determined length from the proximal part and a second portion extending in the longitudinal direction over a determined length between the first portion and the distal part of said fibrous texture,

[0031] characterized in that, when weaving the second portion of the fibrous texture, weft threads made of a second type of fibers having a second al elongation at break greater than the first elongation at break are inserted into at least one zone with increased elongation extending over a determined width in the lateral direction and set back from the first and second lateral edges of the fibrous texture, said at least one zone with increased elongation also comprising weft threads made of the first type of fibers, the weft threads present in the zones of the second portion located outside said at least one zone with increased elongation being made of the first type of fibers.

[0032] The method of the invention allows, as already described above, the production of a fibrous texture which comprises one or more zones with increased elongation, the length of which along the direction of the warp threads and the width of which along the direction of the weft threads can be perfectly delimited in the fibrous texture. This makes it possible to form a casing made of composite material with one or more zones having particular mechanical properties making it possible to improve the resistance to a non-perforating impact, without modifying the mechanical properties of the other parts of the casing. The fibrous texture thus manufactured therefore allows the production of casings made of composite material having improved resistance to a non-perforating impact while retaining good resistance to a displacement / deformation wave.

[0033] According to a characteristic of the method of the invention, during the weaving of the second portion of the fibrous texture, the weft threads of the second type of fibers are inserted into the zone(s) of increased elongation on the side of the external face of the fibrous texture, the weft threads present in the zone(s) of increased elongation present on the side of the internal face of the fibrous texture being made up of the first type of fibers.

[0034] According to another characteristic of the method of the invention, the quantity of weft threads made up of the second type of fibers present in the zone(s) with increased elongation is between 10% and 50% of the number of weft threads present in said zone(s) with increased elongation.

[0035] According to one embodiment of the method of the invention, during the weaving of the second portion of the fibrous texture, weft yarns of the first type of fibers are removed from the fibrous texture before or in the zone(s) of increased elongation while the weft yarns of the second type of fibers are inserted into the fibrous texture in the zone(s) of increased elongation, weft yarns of the first type of fibers being reintroduced into the zone(s) of increased elongation or after said zone(s).

[0036] According to another embodiment of the method of the invention, the zone(s) with increased elongation in the second portion of the fibrous texture are woven with a number of layers of warp threads and layers of weft threads greater than the number of layers of warp threads and layers of weft threads in the other parts of the second portion and the first portion of said fibrous texture. Brief description of the drawings

[0037] [Fig.l] [Fig.l] is a schematic perspective view of a loom showing the three-dimensional weaving of a fibrous texture,

[0038] [Fig.2] [Fig.2] is a schematic perspective view of a fibrous texture in accordance with one embodiment of the invention,

[0039] [Fig.3] [Fig.3] is a cross-section taken at an increased elongation zone of the fiber texture of [Fig.2] and showing a weave pattern in accordance with one embodiment of the invention,

[0040] [Fig.4] [Fig.4] is a cross-section taken at an increased elongation zone of the fiber texture of [Fig.2] and showing a weave pattern in accordance with another embodiment of the invention,

[0041] [Fig.5] [Fig.5] is a schematic perspective view showing the winding of a fibrous texture onto a shaping tool,

[0042] [Fig.6] [Fig.6] is a half axial sectional view of a casing preform obtained by winding a fibrous texture as shown in [Fig.5],

[0043] [Fig.7] [Fig.7] is a sectional view showing the positioning of injection sectors on the preform of the casing of [Fig.6],

[0044] [Fig.8] [Fig.8] is a perspective view of an aeronautical engine in accordance with one embodiment of the invention. Description of the embodiments

[0045] The invention applies generally to fibrous textures intended for the manufacture of casings made of composite material, these casings comprising a barrel or a ferrule with annular flanges at their ends.

[0046] As shown in [Fig.l], a fibrous texture 100 is produced in a known manner by weaving using a jacquard type loom 5 on which a bundle of warp threads or strands 20 has been arranged in a plurality of layers, the warp threads being linked by weft threads or strands 30.

[0047] The fibrous texture is produced by three-dimensional weaving. By "three-dimensional weaving" or "3D weaving" is meant here a weaving method by which at least some of the weft threads bind warp threads over several layers of warp threads or vice versa. The fibrous texture may have an interlock weave. By "interlock" weave is meant here a weaving weave in which each layer of weft threads binds several layers of warp threads, with all the threads of the same weft column having the same movement in the plane of the weave. Other weaving weaves are conceivable.

[0048] As illustrated in [Fig.2], the fibrous texture 100 has a strip shape comprising an internal face F1 and an external face F2. The fibrous texture 100 extends lengthwise in a longitudinal direction X corresponding to the direction of travel of the warp threads or strands 20 and widthwise or transversely in a lateral direction Y between a first lateral edge 101 and a second lateral edge 102, the lateral direction Y corresponding to the direction of the weft threads or strands 30. The fibrous texture extends longitudinally over a determined length LiOo in the X direction between a proximal portion 110 intended to form the start of the winding of a fibrous preform on a shaping tool and a distal portion 120 intended to form the end of the winding of the fibrous preform. The fibrous texture extends transversely over a determined width l100 in the Y direction between the first and second lateral edges 101 and 102.

[0049] The length Li00 of the fibrous texture 100 is determined as a function of the circumference of the tooling or the shaping mold so as to allow the production of a determined number of turns of the fibrous texture, for example four turns.

[0050] The fibrous texture 100 comprises a first portion PI and a second portion P2. The first portion PI extends in the longitudinal direction X over a determined length LP1 from the proximal portion 110 and the second portion P2. The second portion P2 extends in the longitudinal direction X over a determined length LP2 between the first portion PI and the distal portion 120 of the fibrous texture 100. The first portion PI is intended to form the first part of the winding forming the fibrous reinforcement of the casing while the second portion P2 is intended to form the second part of the winding forming the fibrous reinforcement of the casing (respectively radially internal and external parts of this winding, see [Fig. 7] which shows the radial direction R). The length LP2 of the second portion P2 is preferably defined so as to correspond to the last winding turn on the shaping tool or mold ([Fig. 7]).

[0051] According to the invention, the second portion P2 of the fibrous texture 100 comprises an increased elongation zone ZA extending over a length LZA along the longitudinal direction X and over a width 1ZA determined along the lateral direction Y and set back from the first and second lateral edges 101 and 102 of the fibrous texture. In the example described here, the length ZLA of the increased elongation zone ZA is equal to the length LP2 of the second portion P2. The length ZLA of the increased elongation zone ZA is preferably less than or equal to the length LP2 of the second portion P2 so as to be present only at the level of the last winding turn or external turn of the fibrous reinforcement. The width 1ZA is defined as a function of the width of the area of ​​interest of the final casing on which it is desired to locally obtain a higher elongation break. The second portion P2 comprises a first zone 130 extending in the lateral direction Y between the first lateral edge 110 and the increased elongation zone ZA and a second zone 140 extending in the lateral direction Y between the increased elongation zone ZA and the second lateral edge 102. The first and second zones 130 and 140 correspond to the part of the second portion P2 located outside the increased elongation zone.

[0052] The first portion PI and the first and second zones 130 and 140 of the second portion P2 of the fibrous texture comprise warp threads or strands and weft threads or strands made of a first type of fibers having a first elongation at break. The warp threads and the weft threads made of the first type of fibers are intended to confer stiffness to the casing and may be made in particular of carbon fibers.

[0053] Still in accordance with the invention, the increased elongation zone comprises Ti weft yarns made of the first type of fibers and T2 weft yarns made of a second type of fibers having a second elongation at break greater than the first elongation at break. The T2 weft yarns may in particular be made of glass fibers, basalt fibers or aramid fibers.

[0054] Thus, when weaving the second portion of the fiber texture P2, weft threads T2 made of the second type of fibers are inserted at the level of the increased elongation zone ZA.

[0055] [Fig.3] illustrates a plane of the interlock weave armor in the second portion P2 of the fiber texture 100 located at the level of the increased elongation zone ZA in accordance with an embodiment of the invention.

[0056] The example of the weave plan illustrated in [Fig. 3] comprises eight warp layers C ci to CC8 and six weft layers Cn to CT6. Usable interlock weave weaves are described in WO 2006 / 136755.

[0057] In the illustrated example, all the warp yarns of the warp yarn layers CCi to CCs are yarns Ci made of the first type of fibers. The weft yarns of the weft yarn layers CT4 to CT6 are also yarns T i made of the first type of fibers which extend over the entire width liOo of the fiber texture 100, that is to say in the zones 130 and 140 as well as in the increased elongation zone ZA on the side of the internal face F1 of the fiber texture.

[0058] According to the invention and as illustrated in [Fig. 3], during the weaving of the second portion P2 of the fibrous texture 100, weft yarns T2 made of the second type of fibers having a second elongation at break greater than that of the first type of fibers are inserted into an increased elongation zone ZA. More precisely, the weft yarns Ti of the layers of weft yarns CTi to CT3 present in the second zone 140 are removed from the fibrous texture before the increased elongation zone ZA in order to be replaced by weft yarns T2 inserted at the beginning of the zone with increased elongation ZA and woven with warp yarns following the weave pattern. The weft yarns T2 inserted in the layer of weft yarns Cn to CT3 are taken out of the fiber texture at the end of the increased elongation zone ZA in order to be replaced by weft yarns Ti inserted at the beginning of the first zone 130 and woven with warp yarns following the weave pattern.

[0059] By replacing certain Ti weft threads with T2 weft threads in a given part of the fibrous texture, a zone with increased elongation is locally obtained by the presence of T2 weft threads without increasing the thickness of the fibrous texture.

[0060] [Fig.4] illustrates a plane of the interlock weave in the second portion P2 of the fiber texture 100 located at the increased elongation zone ZA in accordance with another embodiment of the invention which differs from the embodiment of [Fig.3] in that the second portion P2 of the fiber texture 100 is woven with a number of layers of warp threads and layers of weft threads greater than the number of layers of warp threads and layers of weft threads of the other parts of the second portion P2 and of the first portion PI of said fiber texture.

[0061] More specifically, the example of the weave plan illustrated in [Fig. 4] comprises in the whole of the fiber texture 100, that is to say in the first and second portions PI and P2 eight warp layers Cci to CCs and six weft layers CTi to CT6-

[0062] In the illustrated example, all the warp threads of the warp thread layers CCi to CCs are threads Ci made of the first type of fibers. The weft threads of the weft thread layers CTi to CT6 are also threads T i made of the first type of fibers which extend over the whole width l100 of the fiber texture 100, that is to say in the zones 130 and 140 as well as in the zone with increased elongation ZA.

[0063] According to the invention and as illustrated in [Fig. 4], when weaving the second portion P2 of the fibrous texture 100, layers of additional weft yarns CT7 to CT9 comprising weft yarns T2 made of the second type of fibers having a second elongation at break greater than that of the first type of fibers are woven with warp yarns Ci belonging to layers of additional warp yarns Cc9 to CCn in a zone of increased elongation ZA.

[0064] In this case, the fibrous texture 100 has an excess thickness at the level of the increased elongation zone ZA present in the second portion P2. The presence of weft threads T2 in a portion of excess thickness of the fibrous texture 100 makes it possible to locally form an increased elongation zone while retaining warp threads Ci and weft threads Ti made up of the first type of fibers in the layers of warp threads C ci to Ces and Cn to CT6 in the entire fibrous texture.

[0065] Examples have just been described in which the fibrous texture has a weave of interlock weave with eight layers of warp yarns and six layers of weft yarns (apart from the additional layers of warp and weft yarns in [Fig. 4]). However, it does not depart from the scope of the invention if the number of weft and warp layers is different, or if the fiber texture has a weave pattern different from an interlock weave.

[0066] According to a particular characteristic, the weft threads T2 made up of the second type of fibers are preferably present on the side of the external face F2 of the fiber texture in the zone with increased elongation while the weft threads Ti made up of the first type of fibers are present on the side of the internal face F1 of the fiber texture in said zone with increased elongation.

[0067] According to another particular characteristic, the quantity of weft threads T2 made up of the second type of fibers present in the zone with increased elongation is between 10% and 50% of the number of weft threads present in said zone with increased elongation.

[0068] As illustrated in [Fig. 5], a casing fiber reinforcement is formed by winding the previously described fiber texture 100 onto a mandrel 50, the fiber reinforcement constituting a complete tubular fiber preform of a casing forming a single piece. For this purpose, the mandrel 50 has an external surface 51 whose profile corresponds to the internal surface of the casing to be produced. The mandrel 50 also comprises two flanges 52 and 53 to form fiber preform parts 62 and 63 corresponding to the flanges of the casing (the flanges 62 and 63 are visible in [Fig. 6]). The turn(s) located radially towards the inside of the preform correspond to the first portion P1 of the fiber texture and the turn(s) located radially towards the outside of the preform correspond to the second portion P2 of the fiber texture. In the example described here and as illustrated in [Fig.7], the preform 60 comprises four turns of fibrous texture 100, the first three turns being formed by the first portion PI while the last turn corresponding to the external layer of the preform is formed by the second portion P2 comprising the zone with increased elongation.

[0069] [Fig. 6] shows a sectional view of the fiber preform 60 obtained after winding the fiber texture 100 in several layers on the mandrel 50. The number of layers or turns depends on the desired thickness and the thickness of the fiber texture. It is preferably at least equal to 2. According to the invention, the fiber preform 60 comprises the increased elongation zone obtained by inserting weft threads of the second type of fiber having an elongation at break greater than that of the other threads of the preform. The axial length along an axial direction D a of the increased elongation zone is defined as a function of the area of ​​interest on which it is desired to improve the resistance to a non-perforating impact.

[0070] The fiber preform 60 is then densified using a matrix.

[0071] The densification of the fibrous preform consists of filling the porosity of the preform, in all or part of its volume, with the material constituting the matrix.

[0072] The matrix can be obtained in a manner known per se using the liquid method. The liquid method consists of impregnating the preform with a liquid composition containing an organic precursor of the matrix material. The organic precursor is usually in the form of a polymer, such as a resin, optionally diluted in a solvent. The fibrous preform is placed in a mold that can be closed in a sealed manner with a housing having the shape of the final molded part. As illustrated in [Fig. 7], the fibrous preform 60 is here placed between a plurality of sectors 54 forming a counter-mold and the mandrel 50 forming a support, these elements having respectively the external shape and the internal shape of the casing to be produced. Then, the liquid matrix precursor, for example a resin, is injected throughout the housing to impregnate the preform.

[0073] The transformation of the precursor into an organic 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 still being maintained in the mold having a shape corresponding to that of the part to be produced. The organic matrix can be obtained in particular from epoxy resins, such as, for example, the high-performance epoxy resin sold, or from liquid precursors of carbon or ceramic matrices.

[0074] The densification of the fiber preform can be carried out by the well-known transfer molding process known as RTM (“Resin Transfer Molding”). According to the RTM process, the fiber preform is placed in a mold having the shape of the casing to be produced. A thermosetting resin is injected into the internal space delimited between the part made of rigid material and the mold and which includes the fiber preform. A pressure gradient is generally established in this internal space between the place where the resin is injected and the orifices for discharging the latter in order to control and optimize the impregnation of the preform by the resin.

[0075] The resin used may 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 must be subjected. Once the resin has been injected throughout the reinforcement, it is polymerized by heat treatment in accordance with the RTM process.

[0076] After injection and polymerization, the part is demolded. The part is finally trimmed to remove excess resin and the chamfers are machined to obtain a housing 810 having a shape of revolution as illustrated in [Fig.8].

[0077] The casing 810 shown in [Fig. 8] is a casing of a fan of an aeronautical gas turbine engine 80. Such an engine, as shown very schematically by [Fig. 7] comprises, from upstream to downstream in the direction of the gas flow, a fan 81 arranged at the inlet of the engine, a compressor 82, a combustion chamber 83, a high-pressure turbine 84 and a low-pressure turbine 85. The engine is housed inside a casing comprising several parts corresponding to different elements of the engine. Thus, the fan 81 is surrounded by the casing 810.

[0078] Furthermore, the casing 810 comprises a local annular zone 811 corresponding to the increased elongation zone ZA produced in the fibrous texture and which has improved resistance to non-perforating impact.

[0079] In the example described herein, the fibrous texture used to form the fibrous reinforcement of the composite material casing comprises an area of ​​increased elongation. However, the fibrous texture may comprise several such areas depending on the needs on the final part.

Claims

Claims

1. Fibrous texture (100) having a strip shape comprising an inner face (F1) and an outer face (F2), the fibrous texture extending in a longitudinal direction (X) over a determined length (L10) between a proximal portion (110) and a distal portion (120) and in a lateral direction (Y) over a determined width (L10) between a first lateral edge (101) and a second lateral edge (102), the fibrous texture having a three-dimensional weave between a plurality of layers of warp threads (20) extending in the longitudinal direction and a plurality of weft layers (30) extending in the lateral direction, the warp threads (C1) and the majority of the weft threads (T1) being made of a first type of fiber having a first elongation at break,the fibrous texture further comprising a first portion (PI) extending in the longitudinal direction over a determined length (Lpi) from the proximal part (110) and a second portion (P2) extending in the longitudinal direction over a determined length (LP2) between the first portion and the distal part of said fibrous texture, characterized in that the second portion (P2) comprises at least one zone with increased elongation (ZA) extending over a width (1ZA) determined in the lateral direction (Y) and set back from the first and second lateral edges (101, 102) and in that said at least one zone with increased elongation (ZA) comprises weft threads (TJ) made of the first type of fibers and weft threads (T2) made of a second type of fibers having a second elongation at break greater than the first elongation at break,the weft threads (Ti) present in the zones of the second portion located outside said at least one zone with increased elongation being made up of the first type of fibers.,

2. Fibrous texture according to claim 1, in which weft threads (T2) present in said at least one zone with increased elongation on the side of the external face (F2) of the fibrous texture (100) are made of the second type of fibers, the weft threads (TJ present in said at least one zone with increased elongation present on the side of the internal face (F1) of the fibrous texture (100) being made of the first type of fibers.

3. A texture according to claim 1 or 2, wherein the amount of yarns of weft (T2) made up of the second type of fibers present in said at least one zone with increased elongation (ZA) is between 10% and 50% of the number of weft threads present in said at least one zone with increased elongation.

4. Texture according to any one of claims 1 to 3, wherein the second portion (P2) of the fibrous texture (100) comprises a number of warp yarn layers (Cci-Ccs) and weft yarn layers (CTi-CT6) similar to the number of warp yarn layers and weft yarn layers of the first portion (PI) of said fibrous texture.

5. Texture according to any one of claims 1 to 3, wherein said at least one zone of increased elongation (ZA) in the second portion (P2) of the fibrous texture (100) comprises a number of warp yarn layers (Cci-Ccu) and weft yarn layers (Cn-Crç) greater than the number of warp yarn layers (Cci-Ccs) and weft yarn layers (CTi-CT6) of the other parts of the second portion (P2) and of the first portion (PI) of said fibrous texture.

6. Fibrous preform (60) of an aeronautical casing (810) comprising a winding over several turns of a fibrous texture (100) according to any one of claims 1 to 5, the first portion (PI) being located on the side of a radially internal face of the preform, and the second portion (P2) being located on the side of a radially external face of the preform.

7. Gas turbine casing (810) made of a composite material, comprising a fibrous reinforcement consisting of a fibrous preform (60) according to claim 6, and a matrix densifying the fibrous reinforcement.

8. The housing (810) of claim 7, wherein said housing is a gas turbine fan housing.

9. A gas turbine aircraft engine (80) having a housing (810) according to claim 7 or 8.

10. A method of manufacturing a fibrous texture (100) by three-dimensional weaving between a plurality of layers of warp yarns (20) extending in a longitudinal direction (X) and a plurality of layers of weft yarns (30) extending in the lateral direction (Y), the warp yarns (Ci) and the majority of the weft yarns (Ti) being made of a first type of fiber having a first elongation at break, the fibrous texture (100) having a strip shape comprising an inner face (F1) and an outer face (F2), the texture fibrous texture extending in the longitudinal direction (X) over a determined length (LiOo) between a proximal portion (110) and a distal portion (120) and in the lateral direction (Y) over a determined width (l100) between a first lateral edge (101) and a second lateral edge (102), the method comprising weaving a first portion (PI) extending in the longitudinal direction over a determined length (LPi) from the proximal portion (110) and a second portion (P2) extending in the longitudinal direction over a determined length (LP2) between the first portion and the distal portion of said fibrous texture, characterized in that, when weaving the second portion (P2) of the fibrous texture (100),weft threads (T2) made of a second type of fibers having a second elongation at break greater than the first elongation at break are inserted into at least one zone with increased elongation (ZA) extending over a determined width (Iza) in the lateral direction (Y) and set back from the first and second lateral edges (101, 102) of the fibrous texture, said at least one zone with increased elongation (ZA) also comprising weft threads (Ti) made of the first type of fibers, the weft threads (Ti) present in the zones of the second portion located outside said at least one zone with increased elongation being made of the first type of fibers.,

11. Method according to claim 10, wherein, when weaving the second portion (P2) of the fibrous texture (100), the weft threads (T2) of the second type of fibers are inserted into said at least one increased elongation zone (ZA) on the side of the external face (F2) of the fibrous texture (100), the weft threads (Ti) present in said at least one increased elongation zone present on the side of the internal face of the fibrous texture being made up of the first type of fibers.

12. A method according to claim 10 or 11, wherein the quantity of weft yarns (T2) made of the second type of fibers present in said at least one increased elongation zone (ZA) is between 10% and 50% of the number of weft yarns present in said increased elongation zone.

13. A procedure according to any one of claims 10 to 12, wherein, when weaving the second portion (P2) of the fibrous texture (100), weft threads (Ti) of the first type of fibers are taken out of the fibrous texture before or in said at least one elongation zone increased (ZA) while the weft threads (T2) of the second type of fibers are inserted into the fiber texture in said at least one zone with increased elongation, weft threads (TJ) of the first type of fibers being reintroduced into said at least one zone with increased elongation or after said at least one zone with increased elongation.

14. Method according to any one of claims 10 to 12, wherein, said at least one zone of increased elongation (ZA) in the second portion (P2) of the fibrous texture (100) is woven with a number of layers of warp threads (Cci-Ccn) and layers of weft threads (CTi-CT9) greater than the number of layers of warp threads (CcrCcs) and layers of weft threads (CTi-CT6) of the other parts of the second portion (P2) and of the first portion (PI) of said fibrous texture.

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