EP2882646A1

EP2882646A1 - Structural part made of a composite material, such as a rail for a slidable cowl of a thrust reverser of an aircraft engine nacelle

Info

Publication number: EP2882646A1
Application number: EP13756655.0A
Authority: EP
Inventors: Loïc LE BOULICAUT
Original assignee: Aircelle SA
Current assignee: Safran Nacelles SAS
Priority date: 2012-08-09
Filing date: 2013-08-02
Publication date: 2015-06-17
Also published as: CN104520191A; CA2879924A1; WO2014023901A1; FR2994418B1; BR112015001203A2; FR2994418A1; RU2015106638A; US20150152744A1

Abstract

The invention relates to a structural part made of a composite material, such as a rail (3) for a slidable cowl of a thrust reverser of an aircraft engine nacelle, said part including a main portion made of a composite material and defining a groove shape, and a reinforcing portion (15) made of a composite material which is provided at the bottom of said groove and which defines a bearing surface (17) at the bottom of said groove.

Description

STRUCTURAL PIECE OF COMPOSITE MATERIAL SUCH AS A RAIL FOR

HOUSING SLIDER OF MOTOR SHOE INVERTER

AIRCRAFT

The present invention relates to a structural part made of composite material such as a rail for a sliding cowl of an aircraft engine nacelle thrust reverser.

As is known per se, an aircraft engine nacelle comprises a number of movable elements.

In particular, when this platform is equipped with a thrust reverser grids, it can comprise one or more covers mounted sliding on the fixed beams of the nacelle, through rail systems and slides interposed between these beams and hoods .

The actuation of these sliding cowls is effected, as is known per se, by hydraulic or electric actuators.

In a constant effort to gain mass, it is nowadays envisaged to produce the aforementioned beams and rails made of composite materials.

FIG. 1 shows, in cross-section, a beam web 1 on which is fixed a rail 3 accommodating the slideway 5 of a sliding nacelle cover with a thrust reverser with gates.

The web 1 and the rail 3 are each formed by a stack of composite folds.

These folds are stacked so as to give the rail 3 a gutter shape, for receiving an end 7 of the slider 5 of corresponding shape.

As is known per se, the connection zones 9a, 9b of the branches 1 1a, 1 1b of the gutter 3 with the bottom 13 of this gutter, are areas of high stress concentration.

These zones of concentration require a large sizing of the rail 3, and therefore a significant increase in the weight of this rail.

The present invention aims to improve this situation.

In particular, this object of the invention is achieved with a structural part made of composite material such as an aircraft engine nacelle thrust reverser hood rail, this part comprising a main part made of composite material defining a gutter shape. , and an reinforcing part of composite material at the bottom of this gutter defining a bearing surface at the bottom of this gutter.

The reinforcement portion acts as a transition zone of efforts. In the particular case where the part is a rail for an aircraft engine nacelle thrust reverser cowl, the reinforcing part allows a transition of the forces between the associated slide of the sliding cowl and the main part of the rail: side of the slide, this reinforcing portion has a substantially flat surface for optimal distribution of the forces printed by the slide; on the side of the main part of the rail, this reinforcing part can follow the shape of this main part which is the most adapted to take up the constraints generated by the slide.

In particular, thanks to the presence of this reinforcement part, it is possible to choose a main part having a C-section whose branches are connected to the bottom by zones with radii of curvature greater than those of a composite part of the technique. previous, thus limiting the concentration of the stresses in these binding zones.

The composite materials forming the main and reinforcing parts of the structural part can be obtained by weaving, braiding, draping, etc. for example glass fibers or carbon fibers, followed by a resin polymerization step, as is known per se.

According to other optional features of this structural part:

said support surface is substantially flat;

said reinforcing part comprises composite folds which partly fit the inside of the gutter shape of said main part: this makes it possible to avoid a concentration of the stresses in the connection zone between the main part and the part of reinforcement;

- The main and reinforcing parts of said structural part are fixed together with reinforcing son in the third dimension, arranged in the alignment of efforts for optimum efficiency;

said main part is closed at one end of this structural part: this makes it possible to consolidate this structural part at this end: this is particularly useful when the structural part is a rail for a thrust reverser cowl, being noted that As a rule, the rail undergoes from the associated slide with greater stresses at its ends; said reinforcement has a shape adapted to the stresses to be absorbed.

The present invention also relates to an assembly comprising a beam formed at least partly of composite material and at least one structural part according to the foregoing.

According to optional features of the assembly according to the invention:

- The said reinforcement portion exceeds the ends of the structural part and is folded behind a portion of the beam: this folding of the reinforcing portion allows greater strength of the fixation of the structural part on the beam;

- The main part of said structural part is fixed on said beam by rivets;

said reinforcement portion comprises counterbores for receiving these rivets;

- The main and reinforcing portions of said rail are fixed together and to said beam with reinforcement son in the third dimension, arranged in the alignment of efforts for optimum efficiency.

The present invention also relates to a nacelle for an aircraft engine, remarkable in that it is equipped with an assembly according to the foregoing.

Other characteristics and advantages of the present invention will emerge in the light of the description which follows, and on examining the appended figures in which:

FIG. 1 is a cross-sectional view of a beam, a rail and a slider of the prior art, described above;

FIG. 2 is a cross-sectional view of an embodiment of a rail according to the present invention;

FIG. 3a is a cross-sectional view of another embodiment of a rail according to the invention;

FIGS. 3b and 3c are perspective views of a beam and rail assembly according to the embodiment of FIG. 3a;

- Figure 4 is a partial sectional view of another embodiment of a rail according to the invention; FIG. 5 is a perspective view of one end of an embodiment of a rail according to the invention;

- Figure 6 is a sectional view along line VI-VI of the rail of Figure 5;

- Figure 7 is a perspective view of a slide end adapted to cooperate with the rail shown in Figures 5 and 6;

Fig. 8 is a perspective view of a beam web on which a particular fastening mode of an embodiment according to any one of Figs. 2 to 7 can be seen;

- Figure 9 is a sectional view of the assembly of Figure 8 taken along line IX-IX;

FIGS. 10 to 12 are cross-sectional views of different methods of fixing a rail according to the invention to a beam web;

FIGS. 13 to 16 are cross-sectional views of other embodiments of rails according to the invention, and

FIGS. 17 to 19 are sectional views of other applications of the invention.

In all of these figures, identical or similar references designate identical or similar members.

The terms "transverse" and "longitudinal" mean the greatest length of the rail according to the invention.

In the following, we will particularly focus on a rail for thrust reverser cover according to the invention, but it will be seen at the end of the present description that the present invention can be applied more generally to any part in composite having a curvature.

Referring now to FIG. 2, it can be seen that the rail 3 according to the invention actually comprises on the one hand a main part 14 defined by superposed composite folds so as to define a gutter shape, and on the other hand a reinforcing part 1 5 comprising composite plies superimposed on the bottom of this gutter, so as to define a bearing surface 17 substantially flat at the bottom of this gutter.

In the embodiment of FIG. 2, the main part 14 is substantially circular, with a spring-shaped opening 1 9 making it possible to accommodate a glider, particularly a thrust reverser cowl ( see Figure 1). In the example shown in Figure 2, the composite stack defining the reinforcing portion 1 5 substantially fills half of the cylinder indre defined by the main portion 14, but this is of course no limitation.

It should of course be understood that the plies defining the main portion 14 and the reinforcing portion 15 are made of polymerized resin, giving the assembly thus obtained a very high strength, as is well known in the field of materials. composites.

Note that the main parts 14 and reinforcement 1 5 can be obtained by any other method of manufacturing composite materials: weaving, draping, braiding, sewing with carbon fibers, glass, etc.

It will be understood that the circular section of the main part 14 makes it possible to very substantially reduce the stresses imposed on this main part by the glissier (not shown) capable of moving inside this main part 14, in contact with the surfaces. internal rail (branches 1 1 a and 1 1 b): this reduction of stresses in the zones 9a and 9b of the main portion 14 is allowed by increasing the radius of curvature of this portion 14 in these areas.

In other words, the reinforcing part 15 acts as a transition zone, allowing one side to create an optimal geometry for the forces on the corresponding surface of the glissière, and on the other side to allow an optimal geometry for the slide.

Note however that this circular configuration of the main portion 14 is not ideal to allow the attachment of the rail according to the invention to a fixed girder girder: such a circular configuration has the effect of limiting the extent of the contact area of the rail with the corresponding part of the beam.

Therefore, we can usefully implement another embodiment shown in Figures 3a to 3c, wherein the zone 21 of the main portion 14 of the rail which is intended to cooperate with a fixed girder beam 23, is flattened .

This configuration, although slightly less favorable than that of FIG. 2 with respect to the concentration of the stresses, nevertheless makes it possible to obtain radii of curvature of the zones of division 9a, 9b of branches 11a, 11 b with the bottom 13 of the rail 3, which are much larger than those of the prior art (see FIG. 1): in this way the stress concentration in the main part 14 (at the zones 9a and 9b) of the rail 3.

FIG. 4 shows that it can advantageously be envisaged to ensure that the composite plies which define the reinforcing part 15 of the rail partly come into line with the inside of the gutter shape of the main part 14, as this is indicated by the reference 25 of this FIG.

In order to consolidate the rail according to the invention, it is quite possible to consider closing one of these ends, as shown in FIGS. 5 and 6.

To do this, composite plies 29 for closing the end 27 of this rail are provided, as is more particularly visible in FIG. 6 (the lay-up of plies is only an illustrative example, but may be be replaced by any known mode of obtaining composite material).

It may be useful at this time to consider that the slide 5 has an end 31 corresponding to the volume defined by the closed end 27 of the rail 3, as can be seen in FIG. 7.

In order to reinforce the fixing of a rail 3 according to any one of FIGS. 2 to 6, on the web 1 of the associated beam 23, it is conceivable that the reinforcement part 1 5 is positioned at the bottom of the main part. 14 of the rail 3, has over-lengths 33a and / or 33b which are folded behind the web 1, as can be seen in FIGS. 8 and 9: these folded over-lengths are taken in the resin of the web 1 during the polymerization , thus making it possible to obtain a set with very strong cohesion.

The length of each flap is a function of the passage of efforts to be made between the rail 3 and sail 1, as well as the space available at the rear of the sail. It is possible to strengthen these connections by sewing or tufting, for example.

FIGS. 10 to 12 show various fastening means of the rail according to the invention on the associated web 1 of the beam 23, which can be used alone or in combination with the one conq ue of the embodiments of embodiments shown in Figures 2 to 9. The reinforcing portion 1 5 allows the integration of these fastening means.

In FIG. 1 0, it can be seen that the rail according to the invention 3 is fixed on the web 1 by tufting (commonly referred to as "tufting"), that is to say by In this connection, the main part 14 and the reinforcing part 15 of loops 37 of wires 35 (for example carbon), arranged prior to resin polymerization by the needles of a suitable machine, known per se.

Of course, any other type of three-dimensional connection, that is to say made by son disposed in a direction substantially perpendicular to that of the web 1, could be suitable.

As can be seen in FIG. 10, the loops 37 of the threads 35 are made in the mass of the folds of the reinforcing part 15, so that they do not require any modification of the resin injection tool and draping folds of composite.

In the embodiment shown in FIG. 11, conventional rivets 39 which pass through the web 1 and the bottom 13 of the main part 14 of the rail 3 are used, these rivets 39 being covered on the one hand by the plies of composite forming the reinforcing portion 15, and secondly by additional folds 41 disposed on the other side of the web 1 relative to the rail 3.

The embodiment of FIG. 12 is in fact a variant of the preceding one, in which a countersink 43 of the composite folds defining the reinforcement portion 15 is envisaged at the rivets 39, that is to say in fact an interruption. the reinforcing part 15 to the right of these rivets 39, so that they are recessed relative to the bearing surface 17 of the reinforcing portion 15, thus allowing the sliding of the associated slide.

This embodiment can be used in particular during a repair, as a result of damage to the room for example; the counterbore 43 is produced after polymerization of the reinforcing part 15.

As can be understood in the light of the foregoing, the addition of a reinforcing portion 15 to the bottom of the main portion 14 of the rail 3, on the one hand to ensure a flat reception of the corresponding surface of the associated slide, and secondly to adopt the optimal geometry for the main part 14 of the rail 3, vis-à-vis the concentration of constraints.

In particular, this main portion 14 can be provided with radii of curvature for minimizing stress concentrations.

With this optimization, we can reduce the size of the main part 14 of the rail 3, and thus gain mass.

The invention has been described in the particular context of a rail allowing the sliding of a thrust reverser hood to grids, but it Of course, this invention could apply to any other sliding system of an aircraft engine nacelle.

More generally, the present invention could be applied to the reinforcement of any structural part made of composite material having a curvature.

Other variations and applications of the present invention will now be mentioned.

As can be seen in FIG. 13, it is possible to cross the main part 14 of the rail 3 with reinforcing wires 35 (glass or carbon for example) as close as possible, and even inside the zones 9a, 9b subjected to high stresses, thanks to the presence of the reinforcing portion 15 which is itself traversed by these son. The orientation of these threads will be determined according to the efforts involved.

Without the presence of the reinforcing portion 15, these son would be arranged in an area without stress concentration, and their effectiveness would be less.

Optionally, as can be seen in FIG. 14, these wires 35 can also pass through the web 1, and thus make it possible to reinforce the fixing of the rail 3 on this web. Martyr zones can be added for an improvement of the production cycle (installation of reinforcing threads directly in the polymerization tool). Depending on the final geometry, a material addition (called "nail head") may be required, as indicated by reference numeral 45 in FIG.

Furthermore, as can be seen in FIG. 15, the geometry of the reinforcement portion 15 can be adapted so that it has, for example, an internal cross-section 47 and a polygonal outer section 49, depending on the efforts to be made. resume.

Note also that one can consider machining the reinforcing portion 15 to obtain exactly the desired section, in which case sacrificial folds are provided during the manufacture of this reinforcement.

It is also possible to incorporate an insert, for example a metal insert 51, inside the rail 3, on the reinforcing part 1 5, as illustrated in FIG.

Other applications of the invention are visible in FIGS. In FIG. 17, the reinforcing portions 15a and 15b are arranged in the corners of a T-connection between different sets of composite plies 51a, 51b, 51c; optionally, reinforcing threads 35 pass through these folds and the reinforcing portions 15a, 15b so as to consolidate the assembly.

In FIG. 18, a secondary thrust reverser composite rail 53, which normally has a U-shaped section whose angles are at 90 °, here has a rounded section, inside which there is a reinforcement portion 1 crossed by reinforcing son 35 according to the precepts above exposed.

FIG. 1 9 shows an L-shaped part 55 forming part of a front thrust reverser frame structure: in the elbow of this L-shaped piece is a reinforcement portion 1 through which threads of reinforcement 35 in accordance with the precepts set forth above.

Claims

1. Structural component of composite material such as a rail (3) for aircraft engine nacelle thrust reverser cowl, this piece comprising a main part (14) of composite material defining a gutter shape, and a part of reinforcement (15) of composite material at the bottom of this gutter defining a bearing surface (17) at the bottom of this gutter.

2. Structural part (3) according to claim 1, wherein said bearing surface (17) is substantially planar.

3. structural part (3) according to one of claims 1 or 2, wherein said reinforcing portion (15) comprises composite plies (25) which partly fit the interior of the gutter form of said portion main.

4. Structural part (3) according to one of the preceding claims, in which the main (14) and reinforcing (15) parts of said structural part (3) are fixed to each other with threads. reinforcement in the third dimension (35, 37), arranged in the alignment of efforts for optimum efficiency.

5. Structural part (3) according to any one of the preceding claims, wherein said main portion (14) is closed at one end (27) of this structural part.

6. Structural part (3) according to the u u e q u el conq ue previous claims, wherein said reinforcement (15) has a shape adapted to the stresses to be absorbed.

7. Assembly comprising a beam (1, 23) formed at least partly of composite material and at least one structural part (3) according to any one of the preceding claims.

8. The assembly of claim 7, wherein said reinforcing portion (15) protrudes from the ends of this structural part (3) and is folded (33a, 33b) behind a portion of this beam (1, 23).

9. Assembly according to one of claims 7 or 8, wherein the main portion (14) of said structural part (3) is fixed on said beam (1, 23) by rivets (39).

10. The assembly of claim 9, wherein said reinforcing portion (15) comprises countersinks (43) for receiving these rivets (39).

1 1. An assembly according to any one of claims 7 to 10, wherein the main (14) and reinforcing (15) portions of said structural part (3) are fixed together and to said beam (1, 23) with wires reinforcement in the third dimension (35, 37), arranged in the alignment of efforts for optimum efficiency.

12. Nacel for the aircraft engine, comprising at least one assembly according to any one of claims 7 to 11.