TURBINE ENGINE FAN CASING AND AN ASSEMBLY FORMED BY SUCH A CASING AND ACOUSTIC PANELS
A turbine engine fan casing of composite material including fiber reinforcement densified by a matrix is made as a single part with ribs that project from an inside face and/or from the outside face of the casing, each rib including a fiber reinforcement portion connected to the fiber reinforcement of a remainder of the casing by weaving or by stitching. On the inside, the ribs serve to mount acoustic panels to the inside face of the casing to form an assembly including a casing and acoustic panels. On the outside, the ribs enable equipment to be mounted on the casing.
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The invention relates in particular to a fan casing for a turbine engine, in particular an aviation engine.
In such a engine, the fan casing conventionally performs several functions. It defines the air inlet passage into the engine, it supports abradable material on its inside face facing the tips of the fan blades, it incorporates or supports a retention shield forming a trap for debris, it supports on the inside a soundwave absorber structure for acoustic treatment at the inlet to the engine, and on its outside face it supports various pieces of equipment such as harnesses, pipework, and other units.
It is well known to make a fan casing out of fiber-and-matrix composite material, generally comprising fibers and an organic matrix. Thus, Document EP 1 961 923 describes making such a casing by densifying a fiber preform obtained by winding superposed layers of a three-dimensionally woven texture of varying thickness and incorporating preform portions for the retention shield and for flanges at the upstream and downstream ends of the casing.
It is also well known to perform acoustic treatment by fastening acoustic panels on the inside face of the casing in the downstream portion thereof and/or in its upstream portion on one or both sides of an abradable coating. In conventional manner, the panels are in the form of juxtaposed sectors each extending over a fraction of the inside periphery of the casing, and the panels are fastened to the casing by means of inserts incorporated in the panels and by means of screws.
Fastening acoustic panels in that way presents several drawbacks. It requires the use of a large number of parts (inserts and screws), and it requires holes to be drilled in the casing. Likewise, fastening a plurality of pieces of equipment on the outside face of the casing by means of screws requires a large number of holes to be drilled. Unfortunately, with a casing that is made of composite material, repeatedly drilling the casing can harm the mechanical properties of the composite material.
OBJECT AND SUMMARY OF THE INVENTIONAn object of the invention is to avoid such drawbacks, and for this purpose the invention proposes a turbine engine fan casing made of composite material comprising fiber reinforcement densified by a matrix and shaped as a single part with at least one rib that projects from the inside face or the outside face of the casing, the casing being characterized in that each rib comprises a fiber reinforcement portion that is connected to the fiber reinforcement of the remainder of the casing by weaving or by stitching.
Thus, one or more ribs suitable for use in mounting acoustic panels or other pieces of equipment on the inside or outside face of the casing are themselves formed with the casing during its fabrication.
In its longitudinal direction, the or each rib preferably extends substantially axially over a fraction of the axial dimension of the casing.
Advantageously, the fiber reinforcement is formed by a woven texture wound in superposed layers, and the fiber reinforcement portion of the or each rib is secured to the inner or outer layer of the texture by weaving.
According to another of its aspects, the invention provides an assembly made up of a fan casing and acoustic panels fastened to the inside face of the casing, in which assembly the casing is made of composite material comprising fiber reinforcement densified by a matrix and is formed as a single part with ribs that project from the inside face of the casing and that extend axially over a fraction of the axial dimension of the casing, each rib comprising a fiber reinforcement portion that is connected to the fiber reinforcement of the remainder of the casing by weaving or by stitching, and the acoustic panels are housed between the ribs and are fastened thereto.
In an embodiment of the casing and acoustic panel assembly, the fiber reinforcement is formed by a woven texture wound in superposed layers, and the fiber reinforcement portion of each rib is secured to the inner layer of the texture by weaving.
In an embodiment of the casing and acoustic panel assembly, the casing is formed as a single part also including at least one rib that projects from the outside face of the casing and that includes a fiber reinforcement portion connected to the remainder of the fiber reinforcement of the casing by weaving or by stitching.
The casing may carry at least one piece of equipment fastened to such a rib projecting from the outside face of the casing.
In another aspect, the invention also provides a turbine engine fitted with a fan casing or with an assembly as defined above.
The invention can be better understood on reading the following description given by way of non-limiting indication and with reference to the accompanying drawings, in which:
The invention is described below in the context of its application to a fan casing for an airplane turbine engine. As shown diagrammatically in
As shown in
Also, in its portion situated facing the tips of the blades 11, the casing 10 has an abradable coating 12 on its inside face. In known manner, the coating 12 may be made up of juxtaposed panels that are fastened to the casing 10 and lined with an abradable material, e.g. as described in Document EP 2 088 290.
Still in known manner, the casing 10 is provided on its inside face with at least one soundproofing coating. In the embodiment of
In the embodiment of
Each panel 20, 20′ of a set of acoustic panels extends over a portion of the inside periphery of the casing 10, with a set of acoustic panels comprising four or six panels, for example. As is well known, the panels 20, 20′ may be constituted by a honeycomb structure 21, 21′ arranged between an outer skin 22, 22′ pressed against the inside face of the casing 10 and an inner skin 23, 23′ with multiple perforations, the honeycomb being made up of cells defined by walls extending substantially radially between the skins. By way of example, reference may be made to Document FR 2 613 773.
The casing 10 is made of composite material comprising fiber reinforcement densified with a matrix. By way of example, the reinforcing fibers are made of carbon, glass, aramid, or ceramic. The matrix may be an organic matrix, e.g. an epoxy, a bismaleimide, or a polyimide polymer.
The fiber reinforcement may be formed by winding superposed layers or turns of a fiber texture made by three-dimensional weaving or multilayer weaving and shaped so as to obtain a fiber preform having a shape that corresponds to the shape of the fan casing that is to be made, the fiber preform being densified while being held in shape by means of tooling. Document EP 1 961 923 describes an embodiment of such a fiber preform that forms a single piece with preform portions corresponding to the flanges 13, 14 and that is obtained from a multilayer woven texture of varying thickness in order to form a preform portion corresponding to the retention shield 15. Nevertheless, it should be observed that the preform portions corresponding to the flanges 13, 14 could be fabricated separately and connected to the remainder of the preform, e.g. by stitching. It should also be observed that the extra thickness corresponding to the retention shield 15 could be obtained by localized over-winding.
In accordance with the invention, the casing 10 is made as a single piece with one or more ribs projecting from the inside face and/or the outside face of the casing and serving advantageously for mounting acoustic panels and/or other pieces of equipment.
In the embodiment of
In the embodiment of
One way of making a fiber preform for a fan casing having preform portions corresponding to the ribs 16 that are secured to the remainder of the preform is described below with reference to
In
The second portion 32 of the texture 30 extends over a fraction of the width of the first portion 31 at a location corresponding substantially to the location of the ribs 16 relative to the upstream and downstream ends of the casing 10, and it has a length corresponding substantially to the axial dimension of the ribs 16. In the example shown, the second portion 32 has two layers of warp yarns that are linked to the first portion solely at the locations of the connections between the ribs 16 and the remainder of the casing 10, and that are linked to one another solely over lengths that correspond to the developed heights of the ribs 16 on either side of these connection locations. In
In a zone 36,
In order to shape the casing fiber preform starting with the texture 30, the warp yarns of the second portion 32 are eliminated except in the zones 36. In each zone 36, on either side of the warp yarns of the portion 32 that are interlinked with the weft yarns of the portion 31, there then remain woven portions 361 and 362 that are separated from the portion 31 by non-interlinked zones 361′ and 362′ (
After forming a first turn or layer of fiber texture 30 having the preform portions 56 for the ribs 16, the fiber texture is wound on the mandrel 40 so as to form one or more superposed turns or layers, with the fiber texture 30 then being constituted by no more than its first portion 31. The number of turns or layers is a function of the desired total thickness, given the thickness of the fiber texture 30. As shown in
As shown in
By way of example, the preform 50 may be densified by being impregnated with a composition that is a precursor for the desired matrix, e.g. a resin. It is possible to use a well-known impregnation process of the resin transfer molding (RTM) type, with the preform 50 being held between the tooling 40 and complementary tooling (not shown) pressed against its outside surface. After the resin has cured, the densified preform can be extracted from the tooling and finishing machining may optionally be performed on the casing.
In the example shown in
In a variant, the beginning and the end of the first turn or layer of the texture 30 may be at the location of a preform portion for a rib 16, the corresponding zone 36 then being shared as two similar half-zones situated at the ends of the segments of length L of the fiber texture 30.
Naturally, in the embodiment of
The description above relates to making and shaping a fiber preform suitable for incorporating ribs 16 in the fan casing for the purpose of mounting acoustic panels on the inside of the casing.
It is possible to proceed in similar manner for making and shaping a fiber preform making it possible to incorporate one or more ribs in the fan casing that extend axially and that are for use in mounting equipment other than acoustic panels, whether on the inside or on the outside of the casing.
In particular, it is possible to make a fan casing preform that incorporates first preform portions for ribs for use in fastening acoustic panels on the inside, and second preform portions for ribs that are for use in fastening equipment on the outside, as for the casing shown in
In order to obtain a preform 50′, it is possible to wind a woven multilayer texture in superposed turns e.g. on the same principle as that described with reference to
In order to shape the preform 50′, tooling 40 similar to that shown in
The preform 50′ is densified as described for the preform 50.
Claims
1-7. (canceled)
8. A turbine engine fan casing made of composite material, comprising:
- fiber reinforcement densified by a matrix and shaped as a single part with at least one rib that projects from an inside face or an outside face of the casing;
- wherein each rib comprises a fiber reinforcement portion that is connected to the fiber reinforcement of a remainder of the casing by weaving or by stitching.
9. A fan casing according to claim 8, wherein the fiber reinforcement is formed by a woven texture wound in superposed layers, the fiber reinforcement portion of each rib being secured to an inner or outer layer of the texture by weaving.
10. An assembly comprising:
- a fan casing; and
- acoustic panels fastened to an inside face of the casing;
- wherein the casing is made of composite material comprising fiber reinforcement densified by a matrix and is formed as a single part with ribs that project from the inside face of the casing and that extend axially over a fraction of an axial dimension of the casing;
- each rib comprising a fiber reinforcement portion that is connected to the fiber reinforcement of a remainder of the casing by weaving or by stitching; and
- the acoustic panels are housed between the ribs and are fastened thereto.
11. An assembly according to claim 10, wherein the fiber reinforcement is formed by a woven texture wound in superposed layers, the fiber reinforcement portion of each rib being secured to the inner layer of the texture by weaving.
12. An assembly according to claim 10, wherein the casing is formed as a single part also including at least one rib that projects from an outside face of the casing and that includes a fiber reinforcement portion connected to a remainder of the fiber reinforcement of the casing by weaving or by stitching.
13. A turbine engine comprising a fan casing according to claim 8.
14. A turbine engine comprising an assembly according to claim 10.
Type: Application
Filed: May 23, 2012
Publication Date: Jul 31, 2014
Applicant: SNECMA (Paris)
Inventor: Bénédicte Marie Le Borgne (Paris)
Application Number: 14/122,424
International Classification: F01D 25/24 (20060101);