Method of manufacturing a fibrous casing preform with a shaping part

Abstract

Method for manufacturing a fibrous casing preform with a shaping part The invention relates to a method for manufacturing a fibrous aeronautical casing preform (200; 300) comprising winding a main fibrous texture (100) on an external surface of a mandrel (50) having a profile corresponding to the internal profile of the casing to be manufactured, the method being characterized in that it further comprises: - arranging at least one shaping part around the wound main fibrous texture (100) so as to obtain an annular shaping part (600), and - winding at least one secondary fibrous texture (210, 220; 310) around the mandrel (51) so as to at least partially cover the wound main fibrous texture (100) and the annular shaping part (600). Figure for abstract: Fig. 4

Description

Title of the invention: Method for manufacturing a fibrous casing preform with a shaping part Technical field

[0001] The present invention relates to the manufacture of aeronautical casings, and in particular the manufacture of aircraft engine fan casings. Prior art

[0002] An aircraft engine conventionally comprises a fan, comprising a plurality of fan blades and a low-pressure compressor surrounded by a fan casing, also called a "FAN casing" or "retention casing". The fan makes it possible to compress all of the air entering the engine, the air then being separated between a primary flow, which passes through the low-pressure compressor, and a secondary flow.

[0003] In order to improve the performance of the aircraft engine, it is necessary to increase the bypass ratio, that is to say to increase the ratio between the mass flow rate of the primary flow and the mass flow rate of the secondary flow. This increase in the bypass ratio involves in particular an increase in the diameter of the fan, and thus an increase in the diameter of the fan casing. However, such an increase in size promotes the excitation of natural vibration modes of the casing.

[0004] To avoid these natural modes of vibration, it is possible to add stiffeners to the fan casing. These stiffeners are conventionally added by gluing stiffener sectors made of composite material around the casing.

[0005] However, such a method adds numerous manufacturing steps. Indeed, it requires the manufacturing of stiffener sectors in composite material, then the bonding of the stiffener sectors together to obtain an annular stiffener and the bonding of the sectors to the casing, requiring an autoclave. Description of the invention

[0006] In order to overcome the aforementioned drawbacks, the invention proposes a method for manufacturing a fiber preform for an aeronautical casing comprising:

[0007] - winding a main fibrous texture on an external surface of a mandrel having a profile corresponding to the internal profile of the casing to be manufactured, the mandrel extending circumferentially around an axial direction,

[0008] the method being characterized in that it further comprises:

[0009] - the arrangement of at least one shaping piece around the fibrous texture main wound so as to obtain an annular shaping piece, the annular shaping piece being projecting relative to the main fibrous texture along a radial direction perpendicular to the axial direction, and

[0010] - winding at least one secondary fibrous texture around the mandrel of so as to at least partially cover the wound primary fibrous texture and the annular shaping piece, the portion of the at least one wound secondary fibrous texture covering the annular shaping piece forming a stiffener preform portion.

[0011] Thus, the annular shaping part makes it possible to integrate the stiffener from the manufacture of the fiber casing preform, which can be densified by the matrix at the same time as the rest of the fiber casing preform. Thus, the additional manufacturing steps are limited, in particular gluing and autoclaving. In addition, since the fiber reinforcement of the stiffener is continuous with the fiber reinforcement of the casing, the stiffener is more robustly connected to the rest of the casing.

[0012] According to a particular embodiment of the invention, a single secondary fibrous texture completely covers the main fibrous texture and the annular shaping part.

[0013] According to another particular embodiment of the invention, two secondary fibrous textures are wound around the mandrel so that the two secondary fibrous textures overlap on the annular shaping part.

[0014] The overlap of the two fiber textures on the annular shaping part makes it possible to locally increase the thickness. Thus, the stiffener preform part obtained is more rigid.

[0015] According to another particular embodiment of the invention, the two secondary fibrous textures overlap only on the annular shaping part.

[0016] Thus, the double thickness is limited only to the stiffener preform portion and not over the entire fiber casing preform. The mass of the fiber casing preform is thus reduced.

[0017] According to another particular embodiment of the invention, the annular shaping part is made of foam.

[0018] According to another particular embodiment of the invention, the annular shaping part is made of fugitive material. For example, the annular shaping part can be made of salt.

[0019] According to another particular embodiment of the invention, the annular shaping part has a trapezoidal section.

[0020] According to another particular embodiment of the invention, the main fibrous texture is produced in a single piece by three-dimensional weaving.

[0021] The mechanical properties of the casing obtained are thus improved.

[0022] According to another particular embodiment of the invention, the annular part of shaping is achieved by assembling several sectors of annular shaping piece around the main wound fibrous texture.

[0023] The invention also relates to a method for manufacturing an aeronautical casing made of composite material comprising the manufacture of a fibrous aeronautical casing preform as described previously and the densification by at least one matrix of said fibrous preform.

[0024] The invention further relates to an aeronautical casing made of composite material obtained by the method of manufacturing an aeronautical casing as described above. Brief description of the drawings

[0025] [Fig-1] [Fig. 1] is a schematic perspective view of a mandrel having the shape of the casing to be produced, around which a main fibrous texture is wound.

[0026] [Fig.2] [Fig.2] is a schematic sectional view of the main fiber texture of [Fig.l] wound around the mandrel.

[0027] [Fig.3] [Fig.3] is a schematic perspective view of the mandrel and the main fiber texture of Figures 1 and 2 on which a shaping piece is wound.

[0028] [Fig.4] [Fig.4] is a schematic sectional view of a fiber preform of an aeronautical casing arranged around the mandrel according to a first preferred embodiment of the invention.

[0029] [Fig.5] [Fig.5] is a schematic sectional view of a fiber preform of an aeronautical casing arranged around the mandrel according to a second embodiment of the invention. Description of the embodiments

[0030] The method of the invention makes it possible to produce an aeronautical casing, in particular an aircraft engine fan casing. The casing to be produced has an annular shape. The casing to be produced extends circumferentially around a reference axis. Preferably, the casing to be produced comprises an annular flange at each of its ends along the reference axis.

[0031] In order to produce such a casing, a mandrel is used whose external surface corresponds to the internal profile of the casing to be manufactured. An example of such a mandrel is illustrated in [Fig.l]. The mandrel 50 is defined by an axial direction DA, extending along the reference axis of the mandrel 50, and by a radial direction DR, extending perpendicular to the axial direction DA.

[0032] The mandrel 50 comprises a body 51 having an annular geometry. Preferably, the mandrel 50 comprises a first flange 52 arranged at one end of the body 51 in the axial direction DA, and a second flange 53 arranged at the other end of the body 51 in the axial direction DA. The flanges 52 and 53 allow to form the fiber reinforcement of the upstream and downstream external flanges of the casing to be produced.

[0033] Figures 1 and 2 illustrate the winding of a main fibrous texture 100 around the mandrel 50.

[0034] The main fibrous texture 100 is produced in a well-known manner by weaving, for example by means of a jacquard type loom on which a bundle of warp threads has been arranged in a plurality of layers, the warp threads being linked by weft threads.

[0035] In order to obtain interesting mechanical characteristics for the fan casing, the main fibrous texture 100 is preferably 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 warp threads bind weft threads on several layers of weft threads or vice versa. The fibrous texture may have an interlock weave weave. By “interlock” weave is meant here a weave weave in which each layer of warp threads binds several layers of weft threads, with all the threads of the same warp column having the same movement in the plane of the weave. Other weave weaves are conceivable.

[0036] The fibers of the main fibrous texture 100 may be carbon, ceramic, glass or aramid fibers, or a mixture of such fibers. In particular, the main fibrous texture 100 may be made from fibers made of the following materials: silicon carbide, alumina, mullite, silica, an aluminosilicate, a borosilicate, or a mixture of several of these materials. According to a preferred embodiment of the invention, the fibers of the main fibrous texture 100 are made of carbon or glass.

[0037] The main fibrous texture 100 has a strip shape which extends in length along a longitudinal direction Dx and in width along a transverse direction DY. The longitudinal direction Dx may correspond to the direction along which the warp threads extend, and the transverse direction DY may correspond to the direction along which the weft threads extend.

[0038] The width of the main fibrous texture 100 along the transverse direction DY must be adapted to the casing to be produced.

[0039] As illustrated in Figures 1 and 2, the main fibrous texture 100 is wound around the mandrel 50. The winding of the main fibrous texture 100 can be carried out so that the main fibrous texture 100 extends in width in the axial direction DA. Thus, the transverse direction DY and the axial direction DA coincide for the wound main fibrous texture 100. The main fibrous texture 100 makes at least one complete turn of the mandrel 50. The main fibrous texture 100 can make only one complete turn of the mandrel 50. The main fibrous texture 100 can make more than one complete turn of the mandrel 50. In particular, the main fibrous texture 100 can make at least several complete turns of the mandrel 50. Thus, the main fibrous texture 100 can be wound around the mandrel 50 so as to produce several layers 101, 102, 103 around the mandrel 50, as illustrated in [Fig. 2]. In this configuration, the layers thus formed are in contact with each other.

[0040] The main fibrous texture 100 preferably extends over the entire width of the mandrel 50 in the axial direction DA. In particular, the main fibrous texture 100 can cover the flanges 52 and 53. This results in a main fibrous texture 100 wound around a reference axis.

[0041] Thus, the wound main fibrous texture 100 comprises a body portion 110 and possibly one or two flange portions 120 and 130. The body portion 110 of the wound main fibrous texture 100 is superimposed on the body 51 of the mandrel 50. The body portion 110 of the wound main fibrous texture 100 may be formed by several superimposed layers. Thus, the body portion 110 of the wound main fibrous texture 100 extends in the axial direction DA. In other words, in a section plane comprising the reference axis, the body portion 110 of the wound main fibrous texture 100 extends mainly in the axial direction DA. The body portion 110 of the wound main fibrous texture 100 extends in thickness in the radial direction DR.

[0042] In the case where the wound main fibrous texture 100 comprises one or two flange portions 120 and 130, the flange portion(s) 120 and 130 are each adjacent to one of the flanges 52, 53 of the mandrel 50. In other words, the flange portion(s) 120 and 130 each cover one of the flanges 52, 53 of the mandrel 50. The flange portion(s) 120 and 130 of the wound main fibrous texture 100 may each be formed by several superimposed layers. Thus, the flange portion(s) 120 and 130 of the wound main fibrous texture 100 extend in the radial direction DR. In other words, in a section plane comprising the reference axis, the flange portion(s) 120 and 130 of the wound main fibrous texture 100 extend mainly in the radial direction DR. The flange portion(s) 120 and 130 of the wound main fibrous texture 100 extend in thickness in the axial direction DA.

[0043] Thus, the flange portion(s) 120 and 130 of the wound main fibrous texture 100 extend in the radial direction DR each from one of the ends in the axial direction DA of the body portion 110 of the wound main fibrous texture 100. The flange portion(s) 120 and 130 of the wound main fibrous texture 100 are directly adjacent to the body portion 110 of the wound main fibrous texture 100.

[0044] When the main fibrous texture 100 is wound around the mandrel 50, arranges an annular shaping piece 600 around the wound main fiber texture 100 as illustrated in [Fig. 3]. The annular shaping piece 600 can be obtained by winding a shaping piece around the wound main fiber texture 100, as in the example illustrated in [Fig. 3]. The shaping piece is then wound in contact with the wound main fiber texture 100.

[0045] The annular shaping piece can also be obtained by arranging several annular shaping piece sectors around the wound main fibrous texture 100. The annular shaping piece sectors are assembled around the wound main fibrous texture 100 so as to form the annular shaping piece. The annular shaping piece sectors are arranged in contact with the wound main fibrous texture 100.

[0046] The annular shaping part 600 projects in the radial direction DR. Preferably, the annular shaping part 600 has a trapezoid-shaped section. In this case, the “large base” of the trapezoid may be in contact with the wound main fibrous texture 100. In particular, the annular shaping part 600 may have a non-rectangular trapezoid-shaped section. The annular shaping part may have an isosceles trapezoid-shaped section. The section of the annular shaping part 600 may vary circumferentially. For example, in the case of a trapezoidal section, the difference between the length of the shortest “large base” of the trapezoid and the length of the longest “large base” of the trapezoid may be between 0 and 50%.Similarly, the difference between the length of the shortest "small base" of the trapezoid and the length of the longest "small base" of the trapezoid can be between 0 and 50%. The inclination of the sides of the trapezoid can be between 0° and 30°.

[0047] The annular shaping part 600 is preferably made of foam. The annular shaping part 600 may be intended to remain in the final aircraft casing. The annular shaping part 600 may be made of foam and have a trapezoidal section as described above.

[0048] The annular shaping part may also be made of a fugitive material. In this case, the annular shaping part will be absent from the final aeronautical casing. For example, the annular shaping part may be removed during the consolidation or densification of the fibrous casing preform by a die. For example, the annular shaping part may be made of salt. This variant is particularly suitable for the case where the annular shaping part is made by assembling sectors of the annular shaping part. The annular shaping part may be made of a fugitive material and have a trapezoidal section as described above.

[0049] The shaping part(s) for forming the annular shaping part may be hollow. Thus, the mass of the annular shaping part is reduced, which makes it possible to obtain a lighter fiber casing preform. In this case, if the annular shaping part 600 is produced by winding, the wound shaping part will be hollow. If the annular shaping part 600 is produced by assembling sectors of the annular shaping part, one or more of said sectors will be hollow. In this configuration, all of the sectors of the annular shaping part may be hollow. Preferably, in this configuration where the sectors are hollow, said sectors are closed at their ends. Thus, said sectors of the annular shaping part are closed and therefore do not risk filling with matrix material during the consolidation or densification of the fiber casing preform.The annular shaping piece may be hollow or partially hollow and have a trapezoidal cross-section as described above.

[0050] The annular shaping part 600 preferably makes exactly one complete revolution of the mandrel 50. However, it does not depart from the scope of the invention if the annular shaping part 600 makes less than one complete revolution of the mandrel 50, or if the annular shaping part 600 makes more than one complete revolution of the mandrel 50. If the annular shaping part 600 is wound over more than one complete revolution, preferably, the different revolutions of the annular shaping part 600 do not overlap in the radial direction DR.

[0051] When the annular shaping part 600 has been arranged around the mandrel 50, one or more secondary fibrous textures 210, 220 or 310 are wound.

[0052] The secondary fibrous texture(s) are wound around the wound main fibrous texture 100. The secondary fibrous texture(s) are wound in contact with the wound main fibrous texture 100.

[0053] The secondary fibrous texture(s) are produced in a well-known manner by weaving, for example using a jacquard-type loom on which a bundle of warp threads has been arranged in a plurality of layers, the warp threads being linked by weft threads.

[0054] In order to obtain interesting mechanical characteristics for the fan casing, the secondary fiber texture(s) are preferably produced by three-dimensional weaving. The secondary fiber texture(s) may have an interlock weave pattern. Other weave patterns are conceivable.

[0055] The fibers of the secondary fiber textures may be carbon, ceramic, glass or aramid fibers, or a mixture of such fibers. In particular, the secondary fiber texture(s) may be made from fibers made of the following materials: silicon carbide, alumina, mullite, silica, an aluminosilicate, a borosilicate, or a mixture of several of these materials. According to a preferred embodiment of the invention, the fibers of the main fibrous texture 100 are made of carbon or glass.

[0056] The secondary fibrous texture(s) have a strip shape which extends in length in a longitudinal direction and in width in a transverse direction. The longitudinal direction may correspond to the direction in which the warp threads extend, and the transverse direction may correspond to the direction in which the weft threads extend.

[0057] The winding of the secondary fibrous texture(s) may be carried out so that the secondary fibrous texture(s) extend in width along the axial direction D A. Thus, the transverse direction of the secondary fibrous texture(s) and the axial direction DA coincide for the wound secondary fibrous texture(s). The wound secondary fibrous texture(s) may make less than one complete revolution of the mandrel 50. The wound secondary fibrous texture(s) may make at least one complete revolution of the mandrel 50. The secondary fibrous texture(s) may make only one complete revolution of the mandrel 50. The secondary fibrous texture(s) may make more than one complete revolution of the mandrel 50. In particular, the secondary fibrous texture(s) may make several complete revolutions of the mandrel 50.Thus, the secondary fibrous texture(s) can be wound around the mandrel 50 so as to produce several layers around the mandrel 50. In this configuration, the layer(s) thus formed are in contact with each other. Preferably, the secondary fibrous texture(s) do not overlap each other in the radial direction DR.

[0058] According to a first embodiment of the invention illustrated in [Fig.4], when the annular shaping part 600 has been arranged around the mandrel 50, at least two secondary fibrous textures 210 and 220 are wound.

[0059] The winding of the main fibrous texture 100 and the secondary fibrous textures 210 and 220 makes it possible to obtain a fibrous casing preform 200 as illustrated in section in [Fig.4].

[0060] The wound secondary fibrous textures 210 and 220 may cover the entirety of the wound main fibrous texture 100. On the contrary, the wound secondary fibrous textures 210 and 220 may only partially cover the wound main fibrous texture 100.

[0061] The first wound secondary fibrous texture 210 comprises a body portion 211, a stiffener portion 213 and optionally a flange portion 212.

[0062] The body portion 211 of the first wound secondary fibrous texture 210 covers the body 51 of the mandrel 50. The body portion 211 of the first texture wound secondary fibrous texture 210 is in contact with the body portion 110 of the wound main fibrous texture 100. The body portion 211 of the first wound secondary fibrous texture 210 covers the body portion 110 of the wound main fibrous texture 100 in the radial direction DR. The body portion 211 of the first wound secondary fibrous texture 210 may be formed by several superimposed layers. Thus, the body portion 211 of the first wound secondary fibrous texture 210 extends in the axial direction DA. In other words, in a section plane comprising the reference axis, the body portion 211 of the first wound secondary fibrous texture 210 extends mainly in the axial direction DA. The body portion 211 of the first wound secondary fibrous texture 210 extends in thickness in the radial direction DR.

[0063] The body portion 211 of the first wound secondary fiber texture 210 may extend to the end of the wound main fiber texture 100. In contrast, the body portion 211 of the first secondary fiber texture 210 may not extend to the end of the wound main fiber texture 100. Thus, the mass of the first secondary fiber texture 210 is reduced because it is present only at and near the annular shaping part 600. Consequently, the total mass of the casing fiber preform is reduced while retaining a satisfactory stiffener preform portion.

[0064] The stiffener portion 213 of the first wound secondary fiber texture 210 at least partially covers the annular shaping piece 600. The stiffener portion 213 of the first wound secondary fiber texture 210 is at least partially in contact with the annular shaping piece 600. The stiffener portion 213 of the first wound secondary fiber texture 210 comprises an end 214. The end 214 of the stiffener portion 213 is opposite the body portion 211 of the first wound secondary fiber texture 210. The end 214 of the stiffener portion 213 may correspond to the part of the stiffener portion 213 covering the “small base” of the trapezoid forming the annular shaping piece, when the latter has a trapezoid-shaped section.

[0065] The stiffener portion 213 of the first wound secondary fiber texture 210 may be formed as a single layer, as illustrated in [Fig. 4]. However, it does not go beyond the scope of the invention if the stiffener portion 213 of the first wound secondary fiber texture 210 is formed by several superimposed layers.

[0066] In the case where the first wound secondary fibrous texture 210 comprises a flange portion 212, the flange portion 212 of the first wound secondary fibrous texture 210 is adjacent to the flange portion 130 of the wound main fibrous texture 100. In other words, the flange portion 212 of the first wound secondary fibrous texture 210 covers the flange portion 130 of the main fibrous texture 100 rolled up.

[0067] The flange portion 212 of the first wound secondary fiber texture 210 extends in the radial direction DR from one of the ends of the body portion 211 of the first wound secondary fiber texture 210. The flange portion 212 of the first wound secondary fiber texture 210 extends in the radial direction DR from the end of the body portion 211 of the first wound secondary fiber texture 210 opposite the stiffener portion 213. The flange portion 212 of the first wound secondary fiber texture 210 extends in thickness in the axial direction DA.

[0068] The flange portion 212 of the first wound secondary fibrous texture 210 may be formed by a single layer, as illustrated in [Fig. 4]. However, it does not go beyond the scope of the invention if the flange portion 212 of the first wound secondary fibrous texture 210 is formed by several layers superimposed along the axial direction DA.

[0069] The second wound secondary fibrous texture 220 comprises a body portion 221, a stiffener portion 223 and optionally a flange portion 222.

[0070] The body portion 221 of the second wound secondary fiber texture 220 covers the body 51 of the mandrel 50. The body portion 221 of the second wound secondary fiber texture 220 is in contact with the body portion 110 of the wound main fiber texture 100. The body portion 221 of the second wound secondary fiber texture 220 covers the body portion 110 of the wound main fiber texture 100 in the radial direction DR. The body portion 221 of the second wound secondary fiber texture 220 may be formed by several superimposed layers. Thus, the body portion 221 of the second wound secondary fiber texture 220 extends in the axial direction DA. In other words, in a section plane comprising the reference axis, the body portion 221 of the second wound secondary fibrous texture 220 extends mainly in the axial direction DA.The body portion 221 of the second wound secondary fibrous texture 220 extends in thickness along the radial direction DR.

[0071] The body portion 221 of the wound second secondary fiber texture 220 may extend to the end of the wound main fiber texture 100. In contrast, the body portion 221 of the second secondary fiber texture 220 may not extend to the end of the wound main fiber texture 100. Thus, the mass of the second secondary fiber texture 220 is reduced because it is present only at and near the annular shaping part 600. Consequently, the total mass of the casing fiber preform is reduced while retaining a satisfactory stiffener preform portion.

[0072] The stiffener portion 223 of the second wound secondary fiber texture 220 at least partially covers the annular shaping part 600. The stiffener portion 223 of the second wound secondary fiber texture 220 is at least partially in contact with the annular shaping part 600. The stiffener portion 223 of the second wound secondary fiber texture 220 comprises an end 224. The end 224 of the stiffener portion 223 is opposite the body portion 221 of the first wound secondary fiber texture 220. The end 224 of the stiffener portion 223 may correspond to the part of the stiffener portion 223 covering the “small base” of the trapezoid forming the annular shaping part 600, when the latter has a trapezoid-shaped section.

[0073] The stiffener portion 223 of the second wound secondary fiber texture 220 may be formed as a single layer, as illustrated in [Fig. 4]. However, it does not go beyond the scope of the invention if the stiffener portion 223 of the second wound secondary fiber texture 220 is formed by several superimposed layers.

[0074] The stiffener portion 223 of the second wound secondary fiber texture 220 at least partially covers the stiffener portion 213 of the first secondary fiber texture 210. The stiffener portion 223 of the second wound secondary fiber texture 220 may completely cover the stiffener portion 213 of the first secondary fiber texture 210. The first wound fiber texture 210 and the second wound secondary fiber texture 220 may overlap only above the annular shaping part 600. Thus, the first wound fiber texture 210 and the second wound secondary fiber texture 220 may overlap only at their stiffener portions 213 and 223. In particular, the first wound fiber texture 210 and the second wound secondary fiber texture 220 may overlap only at the ends 214 and 224 of the stiffener portions 213 and 223.Thus, the first wound fibrous texture 210 and the second wound secondary fibrous texture 220 can overlap only on the “small base” of the trapezium of the annular shaping part 600, when the latter has a trapezium-shaped section.

[0075] The overlap of the first fibrous texture 210 and the second secondary fibrous texture 220 wound only above the annular shaping part 600 makes it possible to locally increase the thickness of the fibrous casing preform, and thus to locally improve its rigidity at the stiffener, without increasing the mass of the fibrous preform in the other zones. Thus, the stiffener in the final casing has better rigidity and the rest of the casing has a reasonable mass.

[0076] The fibrous casing preform 200 thus obtained comprises a body preform portion, a stiffener preform portion, the annular shaping part 600 and possibly two flange preform portions.

[0077] The body preform portion is formed by the body portion 110 of the wound primary fiber texture 100, by the body portion 211 of the wound first secondary fiber texture 210 and by the body portion 221 of the wound second secondary fiber texture 220. The stiffener preform portion is formed by the stiffener portion 213 of the wound first secondary fiber texture 210 and by the stiffener portion 223 of the wound second secondary fiber texture 220. One of the flange preform parts is formed by one of the flange portions 120 of the wound main fiber texture 100 and the flange portion 222 of the wound second secondary fiber texture 220, while the other flange preform part is formed by the other flange portion 130 of the wound main fiber texture 100 and the flange portion 212 of the wound first secondary fiber texture 210.

[0078] The annular shaping part 600 is disposed between the body preform portion and the stiffener preform portion. The annular shaping part 600 is disposed in contact with the body preform portion and the stiffener preform portion. The annular shaping part 600 makes it possible to shape the stiffener preform portion projecting from the body preform portion in the radial direction DR.

[0079] According to a second embodiment of the invention illustrated in [Fig.5], when the annular shaping part 600 has been arranged around the mandrel 50, a single secondary fibrous texture 310 is wound.

[0080] The winding of the main fibrous texture 100 and the secondary fibrous texture 310 makes it possible to obtain a fibrous casing preform 300 as illustrated in section in [Fig.5].

[0081] The wound secondary fibrous texture 310 may cover the entirety of the wound main fibrous texture 100. On the contrary, the wound secondary fibrous texture 310 may only partially cover the wound main fibrous texture 100.

[0082] The wound secondary fibrous texture 310 comprises two body portions 311 and 321, a stiffener portion 304 and possibly one or two flange portions 312 and 322. The two body portions 311 and 321 of the wound fibrous texture 310 are arranged on either side of the stiffener portion 304 in the axial direction D. HAS-

[0083] The body portions 311 and 321 of the wound secondary fiber texture 310 cover the body 51 of the mandrel 50. The body portions 311 and 321 of the wound secondary fiber texture 310 are in contact with the body portion 110 of the wound primary fiber texture 100. The body portions 311 and 321 of the wound secondary fiber texture 310 cover the body portion 110 of the texture main fibrous texture 100 wound along the radial direction DR. The body portions 311 and 321 of the wound secondary fibrous texture 310 may be formed by several superimposed layers. Thus, the body portions 311 and 321 of the wound secondary fibrous texture 310 extend along the axial direction DA. In other words, in a section plane comprising the reference axis, the body portions 311 and 321 of the wound secondary fibrous texture 310 extend mainly along the axial direction DA. The body portions 311 and 321 of the wound secondary fibrous texture 310 extend in thickness along the radial direction DR.

[0084] The first body portion 311 of the wound secondary fibrous texture 310 may extend to the end of the wound main fibrous texture 100. Similarly, the second body portion 321 of the wound secondary fibrous texture 310 may extend to the end of the wound main fibrous texture 100.

[0085] In contrast, the body portion 311 of the secondary fiber texture 310 may not extend to the end of the wound primary fiber texture 100. Similarly, the body portion 321 of the secondary fiber texture 310 may not extend to the end of the wound primary fiber texture 100. Thus, the mass of the secondary fiber texture 310 is reduced because it is present only at and near the annular shaping part 600. Consequently, the total mass of the casing fiber preform is reduced while retaining a satisfactory stiffener preform portion.

[0086] The stiffener portion 304 of the secondary fiber texture 310 completely covers the annular shaping part 600. The stiffener portion 304 of the secondary fiber texture 310 is in contact with the annular shaping part 600.

[0087] The stiffener portion 304 of the wound secondary fiber texture 310 may be formed in a single layer, as illustrated in [Fig. 5]. However, it does not go beyond the scope of the invention if the stiffener portion 304 of the wound secondary fiber texture 310 is formed by several superimposed layers.

[0088] In the case where the wound secondary fibrous texture 310 comprises one or two flange portions 312 and 322, the flange portion(s) 312 and 322 of the wound secondary fibrous texture 310 are adjacent to the flange portions 120, 130 of the wound main fibrous texture 100. In other words, the flange portion(s) 312 and 322 of the wound secondary fibrous texture 310 each cover one of the flange portions 120, 130 of the wound main fibrous texture 100.

[0089] The flange portion(s) 312 and 322 of the wound secondary fibrous texture 310 extend in the radial direction DR each from one end of one of the body portions 311 or 321 of the wound secondary fibrous texture 310. The flange portion(s) 312 and 322 of the wound secondary fibrous texture 310 extend in thickness along the axial direction DA.

[0090] The flange portion(s) 312 and 322 of the wound secondary fibrous texture 310 may be formed by a single layer, as illustrated in [Fig. 5]. However, it does not go beyond the scope of the invention if the flange portion(s) 312 and 322 of the wound secondary fibrous texture 310 are formed by several layers superimposed along the axial direction DA.

[0091] The fibrous casing preform 300 thus obtained comprises a body preform portion, a stiffener preform portion, the annular shaping part 600 and possibly two flange preform portions.

[0092] The body preform portion is formed by the body portion 110 of the wound main fiber texture 100 and by the body portions 311 and 321 of the wound secondary fiber texture 310. The stiffener preform portion is formed by the stiffener portion 304 of the wound secondary fiber texture 310. One of the flange preform portions is formed by one of the flange portions 120 of the wound main fiber texture 100 and by the flange portion 322 of the wound secondary fiber texture 310, while the other flange preform portion is formed by the other flange portion 130 of the wound main fiber texture 100 and by the flange portion 312 of the wound secondary fiber texture 310.

[0093] The annular shaping part 600 is arranged between the body preform portion and the stiffener preform portion. The annular shaping part 600 is arranged in contact with the body preform portion and the stiffener preform portion. The annular shaping part 600 makes it possible to shape the stiffener preform portion projecting from the body preform portion in the radial direction DR.

[0094] The fibrous casing preform 200 or 300 according to one of the previous embodiments is intended to form the fibrous reinforcement of the aeronautical casing.

[0095] The fibrous casing preform is then densified using at least one matrix. The densification of the fibrous casing preform consists of filling the porosity of said preform, in all or part of the volume thereof, with the material(s) constituting said at least one matrix. The mandrel 50 can be used as part of a mold to carry out the densification or at least one step of the densification.

[0096] The matrix can be obtained in a manner known per se using the liquid process. The liquid process 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 casing preform is placed in a mold that can be sealed with a housing having the shape of the final cast casing.

[0097] Next, the liquid matrix precursor, for example a resin, is injected throughout the housing to impregnate the preform.

[0098] 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 200 or 300 being always maintained in the mold having a shape corresponding to that of the part to be produced. The organic matrix can in particular be obtained from epoxy resins, such as, for example, high-tenacity epoxy resin.

[0099] Preferably, the casing produced is made of organic matrix composite material, in order to obtain a better compromise between mass and mechanical characteristics.

[0100] In the case of the formation of a carbon or ceramic matrix, the heat treatment consists of pyrolyzing the organic precursor to transform the organic matrix into a carbon or ceramic matrix depending on the precursor used and the pyrolysis conditions. For example, liquid carbon precursors may be resins with a relatively high coke content, such as phenolic resins, while liquid ceramic precursors, in particular silicon carbide (SiC), may be resins of the polycarbosilane (PCS) or polytitanocarbosilane (PTCS) or polysilazane (PSZ) type. Several consecutive cycles, from impregnation to heat treatment, may be carried out to achieve the desired degree of densification.

[0101] The densification of the fibrous casing preform can also be carried out by the well-known transfer molding process known as “RTM” for “Resin Transfer Molding” in English. In accordance with the RTM process, the fibrous casing preform is placed in a mold having the shape of the casing to be produced.

[0102] A thermosetting resin is injected into the internal space delimited by the mold which includes the fibrous casing 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.

[0103] 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.

[0104] After injection and polymerization, the composite material casing is demolded, then trimmed to remove excess resin. The resulting casing may be raw, and require machining operations to obtain the final functional casing.

[0105] The aeronautical casing thus obtained comprises a body, at least one stiffener and possibly one or two flanges. The body has an annular shape. The flange(s) are arranged at the end of the body. The stiffener comprises the annular shaping part 600.

[0106] The body preform portion forms the fiber reinforcement of the housing body. The stiffener preform portion(s) form the fiber reinforcement of the stiffener(s) of the housing. The flange preform portion(s) form the fiber reinforcement of the flange(s).

[0107] The fibrous casing preform preferably extends over the entire width of the casing along its axis.

[0108] The expression “between ... and ...” must be understood as including the limits.

Claims

Claims

1. A method of manufacturing a fibrous preform for an aeronautical casing (200; 300) comprising: - winding a main fibrous texture (100) onto an external surface of a mandrel (50) having a profile corresponding to the internal profile of the casing to be manufactured, the mandrel (50) extending circumferentially around an axial direction (DA), the method being characterized in that it further comprises: - arranging at least one shaping piece around the wound main fibrous texture (100) so as to obtain an annular shaping piece (600), the annular shaping piece (600) projecting relative to the main fibrous texture (100) in a radial direction (DR) perpendicular to the axial direction (Da), and - winding at least one secondary fibrous texture (210, 220;310) around the mandrel (51) so as to at least partially cover the wound main fibrous texture (100) and the annular shaping part (600), the portion (213, 223; 304) of the at least one secondary fibrous texture (210, 220; 310) covering the annular shaping part (600) forming a stiffener preform part.;

2. A manufacturing method according to claim 1, wherein a single secondary fiber texture (310) completely covers the wound primary fiber texture (100) and the annular shaping piece (600).

3. A manufacturing method according to claim 1, wherein two secondary fiber textures (210, 220) are wound around the mandrel (51) such that the two secondary fiber textures (210, 220) overlap on the annular shaping piece (600).

4. A manufacturing method according to claim 3, wherein the two secondary fibrous textures (210, 220) overlap only on the annular shaping part (600).

5. A manufacturing method according to any one of claims 1 to 4, wherein the annular shaping piece (600) is made of foam.

6. A manufacturing method according to any one of claims 1 to 5, wherein the annular shaping part (600) has a trapezoidal section.

7. A manufacturing method according to any one of claims 1 to 6, wherein the main fibrous texture (100) is made in a single piece by three-dimensional weaving.

8. Manufacturing method according to any one of claims 1 to 6, wherein the annular shaping part (600) is obtained by assembling several sectors of annular shaping part around the wound main fibrous texture (100).

9. Method for manufacturing an aeronautical casing made of composite material comprising the manufacture of a fibrous preform (200; 300) according to any one of claims 1 to 8 and the densification by at least one matrix of said fibrous preform (200; 300).

10. Aircraft casing made of composite material obtained by the manufacturing method according to claim 9.

Images