Woven fiber texture for the formation of a casing preform

The present invention relates to a method of manufacturing a fiber texture which can be used, in particular, but not exclusively, to form the fiber reinforcement of an aircraft engine fan casing made of composite material.

Background of the invention

The manufacture of a composite material casing 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 housing to be produced and held between the mold and segments forming a counter-mold so as to obtain a fibrous preform.

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 and then transported to an oven or oven in in which the preform is densified with a matrix, the matrix possibly being obtained in particular by injection and polymerization of a resin in the fiber preform.

The housings must perform a retention function by retaining the debris ingested inside the engine, or the blades or blade fragments projected by centrifugation, in order to prevent them from passing through the housing and reaching other parts of the aircraft.

The housings of the state of the art generally perform this function satisfactorily. However, it remains possible to further improve the mechanical resistance of certain casings to impact with a blade, when the latter detaches and is projected onto the casing.

Object and summary of the invention

L'invention vise, selon un premier aspect, une texture fibreuse présentant une forme de bande s'étendant dans une direction longitudinale sur une longueur déterminée entre une partie proximale et une partie distale et dans une direction latérale sur une largeur déterminée entre un premier bord latéral et un deuxième bord latéral, la texture fibreuse présentant un tissage tridimensionnel ou multicouche entre une pluralité de couches de fils ou torons de chaîne s'étendant dans la direction longitudinale et une pluralité de couches de fils ou torons de trame s'étendant dans la direction latérale,

characterized in that a first portion of the fibrous texture present between the proximal part and an intermediate part of the fibrous texture comprises weft threads or strands of carbon fibers and in that a second portion of the fibrous texture present between the intermediate part and the distal part comprises son or weft strands of glass fibers.

The first portion of the fibrous texture is rigid and the second portion of the fibrous texture is elastically deformable. The terms “rigid” and “elastically deformable” must be understood in a relative manner, that is to say that the first portion is more rigid than the second portion, and correspondingly that the second portion is more elastically deformable than the first. In other words, the first portion has greater stiffness than the second portion, the difference in stiffness being conferred by the presence of glass fibers, which are more flexible, and by the presence of carbon fibers, which are more rigid. Glass fibers in fact generally have an elongation at break greater than that of carbon fibers: less than 2% for glass fibers, and more than 3% for carbon fibers.

In an exemplary embodiment, the second portion of the fibrous texture may comprise more son or strands of glass fibers than the first portion. In other words, a volume ratio of son or strands of glass fibers in the second portion may be greater than the volume ratio of son or strands of glass fibers in the first portion (the volume ratio being defined relative to the occupied volume by all the wires or strands of the portion considered). The first portion of the fibrous texture may include more carbon fiber yarns or strands than the second portion. In other words, a volume ratio of carbon fiber threads or strands in the first portion may be greater than the volume ratio of carbon fiber threads or strands in the second portion.

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

The inventors have observed that it was possible to improve the resistance of the casing to impact with a detached blade by imparting significant rigidity to the first turns of the fibrous reinforcement of this casing, and a deformable nature to the last turns of this reinforcement, these latter turns being in fact the most stressed in deformation during impact.

Thus, the fibrous texture according to the invention comprises carbon weft threads or strands in the first portion, intended to form the start of the winding and located on the side of the impact with the blade, in order to confer rigidity. raised to this first portion. In addition, the fibrous texture according to the invention comprises son or strands of glass weft in the second portion, which is intended to form the outer layer or layers of the winding, in order to give a significant elastic deformation capacity to this. second portion, and thus be able to absorb the energy communicated by the dawn while deforming and then be able to restore this energy at dawn by returning to its initial shape.

The invention is therefore based on the use of two different materials, namely carbon and glass, located in particular areas of the fibrous reinforcement, in order to respond optimally to the stresses of the casing during a stress event. blade loss while limiting the mass of the latter.

In an exemplary embodiment, the son or weft strands of glass fibers in the second portion are present on the side of an external face of the texture.

The outer face is intended to form the radially outer face of the fibrous texture, once the latter has been rolled up to form the fibrous reinforcement of the casing.

The inventors have observed that, within a given turn of the winding, the part of the texture situated on the side of the external face was the most stressed in deformation during impact with a detached blade.

Thus, the fact of positioning the son or strands of glass weft on the side of this outer face makes it possible to further improve the resistance of the casing to the deformation imposed upon impact with a detached blade.

In an exemplary embodiment, only part of the weft threads or strands of the second portion are made of glass fibers, the other weft threads or strands of the second portion being made of carbon fibers.

The fact of having in the second portion a mixed presence of glass weft threads or strands and carbon weft threads or strands advantageously makes it possible to further improve the resistance of the casing to impact with a detached blade.

In an exemplary embodiment, the fibrous texture further comprises son or warp strands of glass fibers present on the side of an external face of the fibrous texture, the other son or warp strands of the fibrous texture being made of fibers of carbon.

The addition of glass chain wires or strands further improves the resistance of the housing to the deformation imposed upon impact with a detached vane. The glass warp threads or strands are located here on the side of the external face which constitutes a region subjected to deformation, and the rest of the warp threads or strands is made of carbon. This further improves the deformability while maintaining a satisfactory level of stiffness in the fiber reinforcement.

In particular, the son or strands of glass fiber warp may be present in a central zone in the lateral direction which is set back from the first and second side edges and which extends over a determined width less than the width of said fibrous texture. .

The central zone is intended to be present facing the blades and defines the housing retention zone to be obtained. The function of this housing retention zone is to retain the debris, particles or objects ingested at the inlet of the engine, or the blades or blade fragments detached and projected radially by centrifugation against the housing.

The glass warp threads or strands are in the latter case located in a region highly stressed in deformation, ie on the side of the external face and in the central zone, and the rest of the warp threads or strands is made of carbon. This makes it possible to further improve the deformability while maintaining a satisfactory level of stiffness in the fiber reinforcement.

In an exemplary embodiment, the son or strands of carbon fibers and the son or strands of glass fibers present in the fibrous texture have a similar count.

Such a characteristic is advantageous because by using in the texture of threads or strands of similar size, the textile architecture is not noticeably modified, which makes it possible to maintain a similar misting and similar die pocket sizes in the composite housing. .

The invention also relates to a fiber preform for an aircraft casing comprising a winding over several turns of a fiber texture as described above, 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 outer face of the preform.

The invention also relates to a gas turbine casing made of a composite material, comprising a fibrous reinforcement consisting of a fibrous preform as described above, and a matrix which densifies the fibrous reinforcement.

In an exemplary embodiment, said casing is a gas turbine fan casing.

The invention also relates to an aeronautical gas turbine engine having a casing as described above.

Brief description of the drawings

Other characteristics and advantages of the invention will emerge from the following description, given without limitation, with reference to the appended drawings, in which:

- Figure 1 is a schematic perspective view of a loom showing the three-dimensional weaving of a fibrous texture,

- Figure 2 is a schematic perspective view of a fiber texture according to one embodiment of the invention,

- Figure 3 is a cross section taken at the level of the first portion of the fiber texture of Figure 2 and showing a plane of weaving weave,

FIG. 4 is a cross section taken at the level of the second portion of the fiber texture of FIG. 2 and showing a plane of weaving weave,

- Figure 5 is a schematic perspective view showing the winding of a fiber texture on a forming tool,

- Figure 6 is a half-view in axial section of a housing preform obtained by winding a fiber texture as shown in Figure 5,

- Figure 7 is a sectional view showing the positioning of injection sectors on the preform of the housing of Figure 6,

- Figure 8 is a perspective view of an aeronautical engine in accordance with one embodiment of the invention,

FIG. 9 is a cross section taken at the level of the first portion of a variant of fibrous texture according to the invention and showing a plane of weaving weave, and

FIG. 10 is a cross section taken at the level of the second portion of this variant of fiber texture and showing a plane of weaving weave.

Detailed description of embodiments

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

As shown in FIG. 1, a fibrous texture 100 is produced in a known manner by weaving by means of a jacquard type loom 5 on which a bundle of warp threads or strands 20 has been placed in a plurality of layers, the warp threads being linked by weft threads or strands 30.

The fibrous texture is produced by three-dimensional weaving. The term “three-dimensional weaving” or “3D weaving” is understood here to mean a method of weaving by which at least some of the weft threads bind warp threads on several layers of warp threads or vice versa. The fibrous texture may exhibit an interlock weave weave. By “interlock” weaving is meant here a weaving weave in which each layer of weft threads binds several layers of warp threads, with all the threads of a same weft column having the same movement in the plane of the weft. armor. Other weaving weaves are possible.

As illustrated in FIG. 2, the fiber texture 100 has the shape of a strip which extends lengthwise in a longitudinal direction X corresponding to the direction of travel of the warp threads or strands 20 and in width or transversely in a lateral direction Y between a first and a second lateral edges 101 and 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 direction X between a proximal portion 110 intended forming the start of the winding of a fiber preform on a shaping tool and a distal portion 120 intended to form the end of the winding of the fiber preform.

The fibrous texture also has a central zone 130 extending over a determined width I130 in the Y direction, the central zone 130 being intended to form the barrel or the shell of the casing. The central zone 130 is intended to be present opposite the blades and defines the housing retention zone to be obtained. The central zone 130 is located behind the first 101 and second 102 side edges and extends over a determined width I130 less than the width 110 of the texture 100. The central zone 130 is at an intermediate position between the first and second edges. lateral 101 and 102. The central zone 130 is delimited between two lateral zones 140 and 150 each extending over a determined width, respectively li 40 and liso, in the Y direction. The first lateral zone 140 extends between the first lateral edge 101 and the central zone 130. The second lateral zone 150 extends between the second lateral edge 102 and the central zone 130. Each of the side zones 140 and 150 is intended at least in part to form an annular flange of the housing.

The length Lioo of the fiber texture 100 is determined as a function of the circumference of the tool or of the shaping mold so as to allow the production of a determined number of turns of the fiber texture, for example four turns.

The fibrous texture 100 comprises a first portion PI present between the proximal part 110 and an intermediate part PI of the fibrous texture (the intermediate part PI is visible in FIG. 7). The first portion PI is intended to form the first part of the winding forming the fibrous reinforcement of the casing (radially internal part of this winding, see FIG. 7 which shows the radial direction R). The intermediate part PI can be located at mid-length of the fibrous texture 100, or more generally between a quarter and three-quarter of the length of the fibrous texture 100, for example.

The fibrous texture 100 further comprises a second portion P2, distinct from the first portion PI, and present between the intermediate portion PI and the distal portion 120. The second portion P2 is intended to form the second portion of the winding forming the reinforcement fibrous casing (radially outer part of this winding).

FIGS. 3 and 4 each illustrate a plane of the interlock weaving weave of the fibrous texture 100 located respectively at the level of the first portion PI and of the second portion P2.

The example weave plans shown in Figures 3 and 4 include 7 layers of weft and 8 layers of warp. In the armor

interlock shown, a warp layer is formed from two adjacent warp half-layers offset from each other in the weft direction. We therefore have 16 half-layers of chain positioned in staggered rows. Each weft layer binds 3 warp half layers. One could also adopt a non-staggered arrangement, the warp son of two neighboring warp layers being aligned on the same columns. Usable weaving weaves of the interlock type are described in document WO 2006/136755.

As illustrated in FIG. 3, the first portion PI comprises carbon fiber weft threads or strands, denoted Te. All of the weft threads or strands of the first portion PI can be made of carbon fibers.

In the example illustrated, the fiber texture comprises glass fiber warp threads or strands, denoted Cv, as well as carbon fiber warp threads or strands, denoted Ce.

The son or strands of glass fibers Cv are present on the side of the external face F1 of the fibrous texture. This outer face F1 is intended to form the radially outer face of the fiber preform, once the texture has been rolled up (see FIG. 7). In particular, son or strands of glass fiber Cv warp are present on the outer face F1 of the fiber texture. The son or strands of chain of glass fibers Cv may be present at least in the central zone 130, which is the most mechanically stressed during impact with a detached blade, in order to give this zone optimum deformability. The son or strands of glass fibers Cv may be present only in this central zone 130. As a variant,

In the example illustrated, the other son or warp strands of the fibrous texture are made of carbon fibers, and denoted Ce. These carbon fiber warp threads or strands These are, in particular, present on the side of the internal face F2 of the fibrous texture. This internal face F2 is intended to form the radially internal face of the fiber preform, once the texture is rolled up (see FIG. 7). In particular, carbon fiber warp threads or strands Ce are present on the internal face F2 of the fibrous texture. In this example, carbon fiber warp threads or strands are also present in the side zones 140 and 150.

As illustrated in Figure 4, the second portion P2 comprises son or weft strands of glass fibers, denoted Tv, and weft son or strands of carbon fibers Te. Thus, in the example illustrated, only part of the weft threads or strands of the second portion P2 are made of glass fibers, the other weft threads or strands of the second portion P2 being here made of carbon fibers. However, this does not depart from the scope of the invention when all of the weft threads or strands of the second portion are made of glass fibers. The son or weft strands of glass fibers Tv are present on the side of the external face F1 of the fibrous texture. In particular, son or weft strands of glass fibers Tv are present on the external face F1 of the fibrous texture.

There is therefore a change in the nature of the weft threads or strands when one moves along the longitudinal direction X of the fiber texture 100.

We have just described an example in which the fiber texture has an interlock weave weave with 7 weft layers and 8 warp layers. However, this does not depart from the scope of the invention when the number of weft and warp layers is different, or when the fibrous texture has a weave weave that is different from an interlock weave.

As mentioned above, it is also advantageous for the carbon fiber yarns or strands and the glass fiber yarns or strands present in the fiber texture to have a similar count. The report | T2-T1 | / Tl may, for example, be less than or equal to 10%, where Tl denotes the count of the carbon fiber strands or strands, T2 denotes the count of the glass fiber strands or strands, and | . | denotes the absolute value.

As illustrated in FIG. 5, a fibrous casing reinforcement is formed by winding on a mandrel 50 the fibrous texture 100 described above, the fibrous reinforcement constituting a tubular fibrous preform complete with a casing forming a single piece. To this end, the mandrel 50 has an external surface 51 whose profile corresponds to the internal surface of the casing to be produced. Chuck 50

also comprises two flanges 52 and 53 to form fiber preform parts 62 and 63 corresponding to the flanges of the housing (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 PI of the fiber texture and the turn (s) located radially outwardly of the preform correspond to the second portion P2 of the fiber texture.

Figure 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 is a function of the desired thickness and the thickness of the texture. fibrous. It is preferably at least equal to 2. In the example described here, the preform 60 comprises 4 layers of fiber texture 100.

The fiber preform 60 is then densified with a matrix.

The densification of the fiber preform consists in filling the porosity of the preform, in all or part of the volume thereof, with the material constituting the matrix.

The matrix can be obtained in a manner known per se by the liquid process. The liquid process consists in 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 fiber preform is placed in a sealable mold with a housing in the shape of the final molded part. As illustrated in FIG. 7, the fiber preform 60 is here placed between a plurality of sectors 54 forming a counter-mold and the mandrel 50 forming a support, these elements respectively having the outer shape and the inner shape of the casing to be produced. Then, the liquid matrix precursor is injected,

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 kept in the mold having a shape corresponding to that of the part to be produced. The

organic matrix may in particular be obtained from epoxy resins, such as, for example, the high performance epoxy resin sold, or from liquid precursors of carbon or ceramic matrices.

In the case of the formation of a carbon or ceramic matrix, the heat treatment consists in pyrolyzing the organic precursor to transform the organic matrix into a carbon or ceramic matrix depending on the precursor used and the pyrolysis conditions. By way of example, liquid carbon precursors can be resins with a relatively high coke content, such as phenolic resins, while liquid ceramic precursors, especially of SiC, can be polycarbosilane (PCS) type resins. or polytitanocarbosilane (PTCS) or polysilazane (PSZ). Several consecutive cycles, from impregnation to heat treatment, can be carried out to achieve the desired degree of densification.

The densification of the fiber preform can be carried out by the well known transfer molding process called RTM (“Resin Transfert oulding”). In accordance with 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 piece of rigid material and the mold and which comprises the fiber preform. A pressure gradient is generally established in this internal space between the place where the resin is injected and the discharge orifices of the latter in order to control and optimize the impregnation of the preform by the resin.

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 the 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 into all the reinforcement, it is polymerized by heat treatment in accordance with the RTM process.

After injection and polymerization, the part is demolded. The part is finally cut out to remove the excess resin and the

Chamfers are machined to obtain a housing 810 having a shape of revolution as illustrated in Figure 8.

The casing 810 shown in FIG. 8 is a casing of a gas turbine aeronautical engine fan 80. Such an engine, as shown very schematically by FIG. 8 comprises, from upstream to downstream in the direction of the flow of gas streams, a blower 81 disposed 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 housing comprising several parts corresponding to different elements of the engine. Thus, the fan 81 is surrounded by the casing 810.

FIGS. 9 and 10 show a variant of the fiber texture according to the invention, in which all of the warp threads or strands are made of carbon (chain threads or strands Ce).

The fibrous texture comprises, in its second portion P2, son or strands of glass weft Tv, the latter being located on the side of the external face F1 of the texture as in the embodiment described above. According to this illustrated example, the fiber texture further comprises carbon son or weft strands Te in the first portion PI and in the second portion P2. All of the weft threads or strands of the first portion PI are made of carbon, according to this example.
CLAIMS

1. Fibrous texture (100) having the shape of a band extending in a longitudinal direction (X) over a determined length (Lioo) between a proximal part (110) and a distal part (120) and in a lateral direction (Y ) over a determined width (lioo) between a first side edge (101) and a second side edge (102), the fiber texture having a three-dimensional or multi-layered weave between a plurality of layers of warp yarns or strands (20) s' extending in the longitudinal direction and a plurality of layers of weft threads or strands (30) extending in the lateral direction,

characterized in that a first rigid portion (PI) of the fibrous texture present between the proximal part (110) and an intermediate part (PI) of the fibrous texture comprises carbon fiber weft threads or strands (Te) and in that a second elastically deformable portion (P2) of the fibrous texture present between the intermediate part and the distal part comprises son or weft strands (Tv) made of glass fibers.

2. Fibrous texture (100) according to claim 1, wherein the son or weft strands (Tv) of glass fibers in the second portion (P2) are present on the side of an outer face (Fl) of the texture.

3. Fibrous texture (100) according to claim 1 or 2, wherein only part of the weft threads or strands of the second portion (P2) are made of glass fibers, the other weft threads or strands of the second portion being made of carbon fibers.

4. Fibrous texture (100) according to any one of claims 1 to 3, further comprising son or warp strands (Cv) of glass fibers present on the side of an outer face (F1) of the texture, other warp yarns or strands of the fibrous texture being of carbon fibers.

5. Fibrous texture (100) according to claim 4, wherein the son or warp strands (Cv) of glass fibers are present in a central area (130) in the lateral direction set back from the first and second lateral edges ( 101; 102) and which extends over a determined width (li 30 ) less than the width (lioo) of said fibrous texture.

6. Fibrous texture (100) according to any one of claims 1 to 5, wherein the son or strands (Ce; Te) of carbon fibers and the son or strands (Cv; Tv) of glass fibers present in the fibrous texture exhibit a similar titer.

7. Fibrous preform (60) of an aircraft casing (810) comprising a winding over several turns of a fibrous texture (100) according to any one of claims 1 to 6, the first portion (PI) being located on the side of. a radially inner face (F2) of the preform, and the second portion (P2) being located on the side of a radially outer face (Fl) of the preform.

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

9. Housing (810) according to claim 8, wherein said housing is a gas turbine fan housing.

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