(19)
(11)EP 3 117 986 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
29.04.2020 Bulletin 2020/18

(21)Application number: 16168214.1

(22)Date of filing:  03.05.2016
(51)International Patent Classification (IPC): 
B29C 70/88(2006.01)
F01D 21/04(2006.01)
B29C 53/58(2006.01)
F01D 25/24(2006.01)

(54)

IMPROVED COMPOSITE STRUCTURE WITH LOAD DISTRIBUTION DEVICES, AND METHOD FOR MAKING SAME

VERBESSERTE VERBUNDSTRUKTUR MIT LASTVERTEILUNGSVORRICHTUNGEN UND VERFAHREN ZUR HERSTELLUNG DAVON

STRUCTURE COMPOSITE AMÉLIORÉE AVEC DES DISPOSITIFS DE DISTRIBUTION DE CHARGE ET SON PROCÉDÉ DE FABRICATION


(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

(30)Priority: 17.07.2015 US 201514802149

(43)Date of publication of application:
18.01.2017 Bulletin 2017/03

(73)Proprietor: Honeywell International Inc.
Morris Plains, NJ 07950 (US)

(72)Inventors:
  • WATSON, Bill Russell
    Morris Plains, NJ New Jersey 07950 (US)
  • BRALEY, Michael
    Morris Plains, NJ New Jersey 07950 (US)
  • ROBERTS, Gary
    Morris Plains, NJ New Jersey 07950 (US)

(74)Representative: Houghton, Mark Phillip 
Patent Outsourcing Limited 1 King Street
Bakewell, Derbyshire DE45 1DZ
Bakewell, Derbyshire DE45 1DZ (GB)


(56)References cited: : 
US-A1- 2006 201 135
US-A1- 2014 113 088
US-A1- 2014 003 923
  
      
    Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


    Description

    TECHNICAL FIELD



    [0001] Embodiments of the subject matter described herein relate generally to composite structures and, more particularly, to an improved composite structure with load distribution devices.

    BACKGROUND



    [0002] A certain amount of vibration or shock occurs naturally as a dynamic loading condition in an aircraft turbine engine, and contemporary aircraft turbine engines are designed to accommodate the naturally occurring dynamic loading conditions. However, occasionally, an extreme loading condition occurs. Extreme loading conditions may induce a large impact within the aircraft turbine engine and result in a prolonged unbalanced load. An example of an extreme loading condition is a fan blade out event (wherein there is a loss of a fan blade). In the case of a fan blade out event, the segment of the turbine engine that bears the brunt of the impact is typically a composite structure referred to as the fan case.

    [0003] Generally, a fan blade out event causes a heightened, momentary and direct, increase in transmitted load to the fan case, followed by an unbalanced load. The momentary and direct increase in transmitted load may cause damage, such as a crack, tear, dent, or puncture in the fan case. The resulting unbalanced load may start or exacerbate damage, for example, by inducing damage propagation within or along the fan case for the remainder of aircraft airborne time. Damage propagation, if left unchecked, could result in loss of the aircraft inlet. Therefore, a turbine engine fan case must be designed to tolerate and survive extreme loading conditions such as fan blade out events.

    [0004] Currently, various methods are employed to design composite structures, such as turbine engine fan cases, that tolerate and survive fan blade out. For example, some designs reinforce a composite structure with added layers of metal or composite materials. However, as with many aspects of aircraft design, there is constant pressure to minimize weight, and the extra layers of metal or composite materials for strengthening may unacceptably increase the mass and the weight of the composite structure.

    [0005] US 24/0113088 discloses circumferential stiffeners for composite fan cases comprising woven preforms in which gaps between preforms are not present. US 2/0003923 discloses a fan containment case around rather than aft a fan. US 2006/0201135 discloses a composite containment case for turbine engines including braided reinforcement in a woven sheet. Accordingly, an improved composite structure and method for making same is desirable. The improved composite structure has an identified reinforcement region and employs locally strengthened areas therein. The locally strengthened areas within the reinforcement region have load distribution devices that redistribute load in order to (i) locally strengthen an area around damage induced by the initial momentary and direct transmitted load, and (ii) limit propagation of the damage induced by the initial momentary and direct load transmitted load during a subsequent unbalance load. The improved composite structure reduces the impact of the fan blade out phenomenon in a weight efficient manner.

    BRIEF SUMMARY



    [0006] The present invention in its various aspects is as set out in the appended claims. This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description section. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

    [0007] A method of manufacturing a fan case for a turbine engine is provided. The method comprises: fabricating a cylindrical casing comprising composite fibers such that a first fiber of the composite fibers has a first fiber axis oriented tangentially around the cylindrical casing, the cylindrical casing having a forward end, an aft end, and an axis; determining an area on the cylindrical casing to be a reinforcement region; disposing a first load distribution device (LDD) that comprises composite fibers along the reinforcement region such that (i) a fiber of the composite fibers of the first LDD has a second fiber axis that is oriented to be within a range of plus or minus 30 degrees from perpendicular to the first fiber axis of the cylindrical casing, and (ii) the first LDD does not cover more than 50% of the reinforcement region; and coupling the first LDD to the cylindrical casing.

    [0008] A fan case assembly is also provided. The fan case assembly comprises: a cylindrical casing comprising composite fibers such that a first fiber of the composite fibers has a first fiber axis oriented tangentially around a circumference of the cylindrical casing, the cylindrical casing having a forward end, an aft end, an axis, and a reinforcement region; and a first load distribution device (LDD) coupled to the reinforcement region, the first LDD comprising composite fibers and disposed along the reinforcement region such that (i) a determining an area on the cylindrical casing to be a reinforcement region; disposing a first load distribution device (LDD) that comprises composite fibers along the reinforcement region such that (i) a fiber of the composite fibers of the first LDD has a second fiber axis that is oriented to be within a range of plus or minus 30 degrees from perpendicular to the first fiber axis of the cylindrical casing, and (ii) the first LDD does not cover more than 50% of the reinforcement region; and coupling the first LDD to the cylindrical casing.

    [0009] A fan case assembly is also provided. The fan case assembly comprises: a cylindrical casing comprising composite fibers such that a first fiber of the composite fibers has a first fiber axis oriented tangentially around a circumference of the cylindrical casing, the cylindrical casing having a forward end, an aft end, an axis, and a reinforcement region; and a first load distribution device (LDD) coupled to the reinforcement region, the first LDD comprising composite fibers and disposed along the reinforcement region such that (i) a fiber of the composite fibers of the first LDD has a second fiber axis that is oriented to be within a range of plus or minus 30 degrees from perpendicular to the first fiber axis of the cylindrical casing, and (ii) the first LDD does not cover more than 50% of the reinforcement region.

    [0010] Also provided is a method of manufacturing a composite structure, the method comprises: fabricating a cylindrical casing comprising composite fibers such that a first fiber of the composite fibers has a first fiber axis oriented tangentially around a circumference of the cylindrical casing, the cylindrical casing having a forward end, an aft end, and an axis; determining an area on the cylindrical casing to be a reinforcement region; interleaving into the reinforcement region a first load distribution device (LDD) that comprises composite fibers such that, (i) a fiber of the composite fibers of the first LDD has a second fiber axis that is oriented to be within a range of plus or minus 30 degrees from perpendicular to the first fiber axis of the cylindrical casing, and (ii) the first LDD does not cover more than 50% of the reinforcement region; and coupling the first LDD to the cylindrical casing.

    [0011] Other desirable features will become apparent from the following detailed description and the appended claims, taken in conjunction with the accompanying drawings and this background.

    BRIEF DESCRIPTION OF THE DRAWINGS



    [0012] A more complete understanding of the subject matter may be derived by referring to the following Detailed Description and Claims when considered in conjunction with the following figures, wherein like reference numerals refer to similar elements throughout the figures, and wherein:

    FIG. 1 is a perspective schematic view of a typical composite structure, in accordance with an exemplary embodiment; and

    FIG. 2 is a perspective schematic view of a fan casing surrounding a fan, in accordance with an exemplary embodiment.


    DETAILED DESCRIPTION



    [0013] The embodiment provided herein describes a cylindrical composite structure, however, a skilled practitioner in the art will readily appreciate that the composite structure may have any shape or form. The exemplary embodiment described herein is merely an example and serves as a guide for implementing the novel systems and method herein in any industrial, commercial, or consumer application. As such, the examples presented herein are intended as non-limiting.

    [0014] FIG. 1 is a perspective schematic view of a typical composite structure 100, in accordance with an exemplary embodiment. Composite structure 100 is cylindrical around axis 102, having a forward side 106 and an aft side 108. The composite structure 100 is comprised of composite fibers, with a first fiber axis 104 that is substantially tangential around a circumference of the composite structure 100.

    [0015] A reinforcement region 110, defined as a region in the composite structure 100 that needs to be strengthened, is determined. The reinforcement region 110 is anticipated to be (i) vulnerable to punctures and damage, such as damage 150, and (ii) vulnerable to propagation of any damage therein. In the embodiment, reinforcement region 110 is substantially a circumferential band that continues circumferentially around the cylindrical composite structure 100, however, reinforcement region 110 may be anywhere on the composite structure 100, and may have any shape or size. The novel concept presented herein provides a method and system for strengthening the reinforcement region 110; specifically, by locally strengthening an area within the reinforcement region, in order to direct loads away from weak areas of the composite structure 100.

    [0016] In order to provide local strengthening within the reinforcement region 110, one or more load distribution devices (LDDs) 116 are disposed axially therein. The provided embodiments employ composite fiber LDDs 116 having at least one fiber (of the composite fibers of the LDD 116) with a second fiber axis that is oriented to be within a range of plus or minus 30 degrees from perpendicular to the first fiber axis of the composite structure 100. The size, material, and placement of the LDDs 116 reflect an application-specific design decision to locally strengthen (and direct load away from) a weak area 118, such as the area around the damage 150, within the reinforcement region 110. Once locally strengthened, an area that includes weak area 118 and the neighboring LDDs 116 may be referred to as a "dead zone" wherein damage propagation is inhibited and loads are directed away. A person with skill in the art will appreciate a weight tradeoff associated with the size, material, and number of LDDs 116 employed. It is contemplated that no more than 50% of the reinforcement region is covered with LDDs 116. For example, in FIG. 1, area 118 plus area 120 plus area 122 comprise a visible portion of reinforcement region 110 that is not covered by LDDs 116.

    [0017] The combination of the orientation of the second fiber axis with respect to the first fiber axis 104 and the size and placement of the LDDs 116, provides several key advantages. One advantage offered by this combination is the ability to target and strengthen only discrete areas within reinforcement region 110, leaving the remaining areas within reinforcement region 110 (as well as the composite structure 100) thinner, and thereby optimizing the weight tradeoff (described above) for a given composite structure 100. Another advantage of the combination is the ability to inhibit circumferential damage propagation within reinforcement region 110, as damage can only propagate to the next neighboring LDD 116, before being inhibited.

    [0018] FIG. 2 is a perspective schematic view of a fan case 200 surrounding a fan 204, in accordance with an exemplary embodiment. Fan case 200 is an application-specific example of an improved composite structure employing LDDs 116. In aircraft design, an aircraft may have multiple turbine engines, each having at least one fan case 200.

    [0019] Fan case 200 comprises a cylindrical casing 202 that is coaxial with and surrounds a fan 204 coupled to one or more LDDs 116. The cylindrical casing 202 has a forward end 106 and an aft end 108. As shown and described in FIG.1, the cylindrical casing 202 comprises composite fibers such that a first fiber of the composite fibers has a first fiber axis (104, FIG. 1) oriented tangentially around the cylindrical casing 202. Fan 204 comprises a plurality of fan blades 206 that rotate around axis 102. A fan blade-out event, as described above, may cause damage such as punctures, cracks or dents to the fan case 200.

    [0020] Within fan case 200, reinforcement region 110 is determined. Reinforcement region 110 may be arbitrarily determined, arrived at by structural analysis, arrived at experimentally, or it may be determined to be associated with a physical feature of the cylindrical casing 202, such as a fan containment housing 250. In the embodiment shown in FIG. 2, the novel concept presented herein provides a method and system for strengthening a reinforcement region 110 that is aft of the fan containment housing 250.

    [0021] In the embodiment of FIG. 2, fan case 200 comprises a plurality of load distribution devices (LDDs) 116. Each LDD 116 of the plurality of LDDs 116 is disposed axially within reinforcement region 110, and each LDD 116 comprises composite fibers and is disposed along the reinforcement region such that (i) a fiber of the composite fibers of each LDD 116 has a second fiber axis that is oriented to be within a range of plus or minus 30 degrees from perpendicular to the first fiber axis (104, FIG. 1) of the cylindrical casing 202. As described above, the size, material, and placement/location of the LDDs 116 reflect an application-specific design decision to locally strengthen and direct load away from a weak area 118. The composite fibers employed in various embodiments may or may not be braided, and the composite fibers of the cylindrical casing 202 may or may not be the same as the composite fibers of the plurality of LDDs 116.

    [0022] The embodiment of FIG. 2 depicts each of the LDDs 116 arranged around the circumference of the cylindrical casing 202 such that any space 224 between any LDD 116 and a neighboring LDD 116 is substantially equal to any other space 224 (it is to be noted that each space 224, which is comprised of weak area 118 and at least a portion of respective neighboring LDDs 116, functions as a dead zone, as described above). Each of the LDDs 116 may be coupled to the cylindrical casing 202 using any currently available technique, such as, with an adhesive, and/or may be interleaved into the fibers of the cylindrical casing 202.

    [0023] The LDDs 116 are localized composite layers that locally strengthen and direct load away from weak areas 118, in the cylindrical casing 202 by acting like a bridge. Each of the LDDs 116 may have a predetermined width 210 and a predetermined length 208 that are optimized to reflect an application-specific design decision. In an embodiment, the predetermined length 208 is substantially nine times the predetermined width 210. LDD 116 placement and orientation may further prevent or inhibit growth and propagation of induced damage. A person with experience in the art will readily appreciate that design optimization entails balancing the strengthening provided by the number of LDDs 116 employed against the weight and mass added by the number of LDDs 116 employed. Accordingly, it is contemplated that optimal designs have less than 50% of the reinforcement region 110 covered by LDDs 116.

    [0024] Thus, an improved composite structure and method for making same has been provided. The provided improved composite structure has locally strengthened areas within a reinforcement region. The locally strengthened areas within the reinforcement region have load distribution devices to redistribute load in order to (i) locally strengthen an area around damage induced by an initial momentary and direct transmitted load, and (ii) limit growth and propagation of damage induced by an initial momentary and direct transmitted load during a subsequent unbalance load. The improved composite structure reduces the impact of the fan blade out phenomenon in a weight efficient manner.


    Claims

    1. A method of manufacturing a fan case for a turbine engine, comprising:

    fabricating a cylindrical casing (100) comprising composite fibers such that a first fiber of the composite fibers has a first fiber axis oriented tangentially around the cylindrical casing (100), the cylindrical casing (100) having a forward end (106), an aft end (108), and an axis (102);

    determining an area on the cylindrical casing to be a reinforcement region, wherein the reinforcement region begins and ends aft of a fan containment housing;
    disposing a plurality of load distribution devices (LDD) (116) axially along the reinforcement region (110), the LDD (116) comprising composite fibers such that:

    (i) for each LDD, a fiber of the composite fibers of the LDDs has a second fiber axis that is oriented to be within a range of plus or minus 30 degrees from perpendicular to the first fiber axis of the cylindrical casing (100), and (ii) first LDDs (116) do not cover more than 50% of the reinforcement region (110); and

    (ii) coupling the first LDD (116) to the cylindrical casing (100);

    (iii) for each of the plurality of LDDs, there exists a space (224) between LDDs, wherein each of the plurality of LDDs is arranged around the cylindrical casing (100) such that the space (224) between an LDD and a neighboring LDD is substantially equal, for each of the plurality of LDDs.


     
    2. The method of Claim 1, wherein coupling the plurality of LDDs to the cylindrical casing (100) comprises interleaving the plurality of LDDs within the composite fibers of the cylindrical casing (100).
     
    3. The method of Claim 1, wherein each of the plurality of LDDs comprises a predetermined width (210) and a predetermined length (208), and wherein the predetermined length (208) is about nine times the predetermined width (210).
     
    4. A fan case assembly, comprising:

    a cylindrical casing (100) comprising composite fibers such that a first fiber of the composite fibers has a first fiber axis oriented tangentially around a circumference of the cylindrical casing, the cylindrical casing having a forward end (106), an aft end (108), an axis (102), a fan containment housing, and a reinforcement region (110) aft of the containment housing (250); and

    a plurality of load distribution devices (LDD) (116) coupled to the reinforcement region (110), the first LDDs (116) comprising composite fibers and being disposed axially along the reinforcement region (110), such that

    (i) a fiber of the composite fibers of the LDDs (116) has a second fiber axis that is oriented to be within a range of plus or minus 30 degrees from perpendicular to the first fiber axis of the cylindrical casing (100), and

    (ii) the LDDs (116) do not cover more than 50% of the reinforcement region (110); the plurality of LDDs being coupled to the cylindrical casing (100),

    (iii) for each of the plurality of LDDs, there exists a space (224) between LDDs, wherein each of the plurality of LDDs is arranged around the cylindrical casing (100) such that a space (224) between an LDD and a neighboring LDD is substantially equal, for each of the plurality of LDDs.


     
    5. The fan case assembly of Claim 4, wherein the plurality of LDDs are coupled to the cylindrical casing (100) by being interleaved into the composite fibers of the cylindrical casing (100).
     


    Ansprüche

    1. Verfahren zur Herstellung eines Gebläsegehäuses für einen Turbinenmotor, umfassend:

    Fertigung einer zylindrischen Hülle (100), die Verbundfasern umfasst, sodass eine erste Faser der Verbundfasern eine erste Faserachse aufweist, die tangential um die zylindrische Hülle (100) herum ausgerichtet ist, wobei die zylindrische Hülle (100) ein vorderes Ende (106), ein hinteres Ende (108) und eine Achse (102) aufweist;

    Bestimmen eines Bereichs auf der zylindrischen Hülle als Verstärkungsbereich, wobei der Verstärkungsbereich hinter einer Gebläseaufnahmeunterbringung beginnt und endet;

    Anordnen einer Vielzahl von Lastverteilungsvorrichtungen (LDD) (116) axial entlang des Verstärkungsbereichs (110), wobei die LDD (116) Verbundfasern umfassen, sodass:

    (i) für jede LDD eine Faser der Verbundfasern der LDD eine zweite Faserachse aufweist, die so ausgerichtet ist, dass sie innerhalb eines Bereichs von plus oder minus 30 Grad von der Senkrechten zur ersten Faserachse der zylindrischen Hülle (100) liegt, und (ii) die ersten LDD (116) nicht mehr als 50 % des Verstärkungsbereichs (110) abdecken; und

    (ii) Koppeln der ersten LDD (116) mit der zylindrischen Hülle (100);

    (iii) für jede der Vielzahl von LDD ein Raum (224) zwischen den LDD existiert, wobei jede der Vielzahl von LDD um die zylindrische Hülle (100) herum angeordnet ist, sodass der Raum (224) zwischen einer LDD und einer benachbarten LDD im Wesentlichen für jede von der Vielzahl von LDD gleich ist.


     
    2. Verfahren nach Anspruch 1, wobei das Koppeln der Vielzahl von LDD mit der zylindrischen Hülle (100) das Verschachteln der Vielzahl von LDD innerhalb der Verbundfasern des zylindrischen Gehäuses (100) umfasst.
     
    3. Verfahren nach Anspruch 1, wobei jede der Vielzahl von LDD eine vorbestimmte Breite (210) und eine vorbestimmte Länge (208) umfasst und wobei die vorbestimmte Länge (208) etwa neunmal so breit wie die vorbestimmte Breite (210) ist.
     
    4. Gebläsegehäuseeinheit, umfassend:

    eine zylindrische Hülle (100), die Verbundfasern umfasst, sodass eine erste Faser der Verbundfasern eine erste Faserachse aufweist, die tangential um einen Umfang der zylindrischen Hülle herum orientiert ist, wobei die zylindrische Hülle ein vorderes Ende (106) und ein hinteres Ende (108), eine Achse (102), eine Gebläseaufnahmeunterbringung und einen Verstärkungsbereich (110) hinter der Aufnahmeunterbringung (250) aufweist; und

    eine Vielzahl von Lastverteilungsvorrichtungen (LDD) (116), die mit dem Verstärkungsbereich (110) gekoppelt sind, wobei die ersten LDD (116) Verbundfasern umfassen und axial entlang des Verstärkungsbereichs (110) angeordnet sind, sodass

    (i) eine Faser aus den Verbundfasern der LDD (116) eine zweite Faserachse aufweist, die so ausgerichtet ist, dass sie in einem Bereich von plus oder minus 30 Grad von der Senkrechten zur ersten Faserachse der zylindrischen Hülle (100) liegt, und

    (ii) die LDD (116) nicht mehr als 50 % des Verstärkungsbereichs (110) bedecken;
    wobei die Vielzahl von LDD mit der zylindrischen Hülle (100) gekoppelt sind,

    (iii) für jede der Vielzahl von LDD ein Raum (224) zwischen den LDD existiert, wobei jeder der Vielzahl von LDD um die zylindrische Hülle (100) herum angeordnet ist, sodass ein Raum (224) zwischen einer LDD und einer benachbarten LDD im Wesentlichen für jede der Vielzahl von LDD gleich ist.


     
    5. Gebläsegehäuseeinheit nach Anspruch 4, wobei die Vielzahl von LDD mit der zylindrischen Hülle (100) gekoppelt ist, indem sie in die Verbundfasern der zylindrischen Hülle (100) eingeschachtelt ist.
     


    Revendications

    1. Procédé de fabrication d'un carter de ventilateur pour turbomachine, consistant à :

    fabriquer un boîtier cylindrique (100) comprenant des fibres composites de telle sorte qu'une première fibre des fibres composites ait un premier axe de fibre orienté tangentiellement autour du boîtier cylindrique (100), le boîtier cylindrique (100) ayant une extrémité avant (106), une extrémité arrière (108) et un axe (102) ;

    déterminer une zone sur le boîtier cylindrique comme étant une région de renforcement, dans lequel la région de renforcement commence et se termine à l'arrière d'un logement de confinement de ventilateur ;

    disposer une pluralité de dispositifs de répartition de charge (LDD) (116) axialement le long de la région de renforcement (110), les LDD (116) comprenant des fibres composites de telle sorte que :

    (i) pour chaque LDD, une fibre des fibres composites des LDD ait un second axe de fibre qui est orienté pour être dans une plage de plus ou moins 30 degrés par rapport à la perpendiculaire au premier axe de fibre du boîtier cylindrique (100) et (ii) les premiers LDD (116) ne couvrent pas plus de 50 % de la zone de renforcement (110) ; et

    (ii) accoupler le premier LDD (116) au boîtier cylindrique (100) ;

    (iii) pour chacun de la pluralité de LDD, il existe un espace (224) entre les LDD, dans lequel chacun de la pluralité de LDD est disposé autour du boîtier cylindrique (100) de sorte que l'espace (224) entre un LDD et un LDD voisin soit sensiblement égal, pour chacun de la pluralité de LDD.


     
    2. Procédé selon la revendication 1, dans lequel l'accouplement de la pluralité de LDD au boîtier cylindrique (100) comprend l'entrelacement de la pluralité de LDD à l'intérieur des fibres composites du boîtier cylindrique (100).
     
    3. Procédé selon la revendication 1, dans lequel chacun de la pluralité de LDD comprend une largeur prédéterminée (210) et une longueur prédéterminée (208) et dans lequel la longueur prédéterminée (208) est environ neuf fois la largeur prédéterminée (210).
     
    4. Ensemble carter de ventilateur, comprenant :

    un boîtier cylindrique (100) comprenant des fibres composites de telle sorte qu'une première fibre des fibres composites ait un premier axe de fibre orienté tangentiellement autour d'une circonférence du boîtier cylindrique, le boîtier cylindrique ayant une extrémité avant (106), une extrémité arrière (108), un axe (102), un logement de confinement de ventilateur et une région de renforcement (110) à l'arrière du logement de confinement (250) ; et

    une pluralité de dispositifs de répartition de charge (LDD) (116) accouplés à la région de renforcement (110), les premiers LDD (116) comprenant des fibres composites et étant disposés axialement le long de la région de renforcement (110), de telle sorte que

    (i) une fibre des fibres composites des LDD (116) ait un second axe de fibre qui est orienté pour être dans une plage de plus ou moins 30 degrés par rapport à la perpendiculaire au premier axe de fibre du boîtier cylindrique (100) et

    (ii) les LDD (116) ne couvrent pas plus de 50 % de la zone de renforcement (110) ; la pluralité de LDD étant accouplée au boîtier cylindrique (100),

    (iii) pour chacun de la pluralité de LDD, il existe un espace (224) entre les LDD, dans lequel chacun de la pluralité de LDD est disposé autour du boîtier cylindrique (100) de telle sorte qu'un espace (224) entre un LDD et un LDD voisin soit sensiblement égal, pour chacun de la pluralité de LDD.


     
    5. Ensemble carter de ventilateur selon la revendication 4, dans lequel la pluralité de LDD sont accouplés au boîtier cylindrique (100) en étant entrelacés dans les fibres composites du boîtier cylindrique (100).
     




    Drawing











    Cited references

    REFERENCES CITED IN THE DESCRIPTION



    This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

    Patent documents cited in the description