Aircraft rear fuselage section and method for manufacturing the aircraft rear fuselage section

Abstract

The present invention relates to a lower fuselage shell for an aircraft rear fuselage section, wherein the lower fuselage shell is made of composite material and comprises at least one lower skin, stringers and frame segments, the stringers being integrally formed with the lower skin and the frame segments extending crosswise relative to the stringers. Shear bands are co-cured or co-bonded with the lower skin and extending crosswise relative to the stringers. The frame segments are fastened to the shear bands, for example so that the frame segments are spaced apart from the lower skin. The present invention also relates to an aircraft rear fuselage section, which comprises an upper fuselage shell and a lower fuselage shell as previously defined. The upper fuselage shell has an upper skin reinforced with Omega-shaped stringers, and the lower shell has a lower skin reinforced with T-shaped stringers. The present invention also relates to a method for manufacturing a rear fuselage section.

Description

Technical Field

[0001] The present invention relates generally to aircraft fuselages. More specifically, the present invention relates to the design and manufacture of a rear fuselage section obtained from composite materials.

[0002] The object of the invention is to increase the speed of production and assembly in the manufacture of a rear fuselage section and thereby reduce the manufacturing costs.

[0003] Another object of the invention is to improve the production accuracy of the components of the rear section so as to meet the overall assembly tolerances. Background Art

[0004] Aircraft fuselages are usually made of composite materials and include a skin reinforced internally by structural components such as stringers bonded to the skin and arranged in the longitudinal direction of the aircraft, and frames arranged transversely relative to the stringers. Typically, the stringers are co-cured or co-bonded with the skin in one molding (one curing cycle), and are therefore usually considered to be integrally formed with the skin.

[0005] As is known to all, the fuselage of an aircraft is produced in several parts, namely: the nose, the tail, the middle section and the rear section, and the multiple sections are assembled together on the final assembly line. Figure 1 As shown, the rear fuselage section 1 is a fuselage section used for installing a vertical tail 2 and a horizontal tail 3 .

[0006] Depending on the size of the aircraft, the skin of the rear section is formed from a single panel extending around the fuselage and obtained in one step, or from several panels or shells produced separately and assembled together at a subsequent stage. In both cases, it is customary to use only one type of stringer for the entire rear fuselage section to strengthen the skin, usually an Omega-shaped stringer in the case of a skin formed from only one panel, or a T-shaped stringer in the case of a skin formed from several panels.

[0007] The same is true for the frames, which are manufactured separately in sections. In some cases, the frames are fastened directly to the skin. In other cases, additional components called shear ties or shear-cleats are used to attach the frames to the skin. The shear ties are fastened to the skin, and the frames are fastened to the shear ties, and given that they can be separated relative to the skin, these frames can be considered floating frames. The process of fastening the shear ties to the skin and the frames to the shear ties is time consuming.

[0008] US Patent Publication US 2010 / 0308172 A1 is an example of the above-mentioned fuselage structure.

[0009] Other fuselage structural components are beams, which serve as frames to reinforce open areas of the skin, such as access panels or skin cutouts.

[0010] One known type of rear fuselage section has lateral cutouts for receiving and allowing trimming of the horizontal stabilizer. US patent US-7810758 B2 shows an example of a rear section of this type.

[0011] Today, aircraft fuselages are made of composite materials such as carbon fiber reinforced plastic (CFRP) or other composite materials.

[0012] In the aerospace industry, there is a constant desire to increase productivity and reduce manufacturing costs. Summary of the invention

[0013] The invention is defined in the attached independent claims and is based on the recognition that different components of the rear fuselage section have different geometries and have to comply with different load requirements. More specifically, since the vertical tail and the horizontal tail are attached to the upper fuselage shell, the upper fuselage shell is highly loaded, while the lower fuselage shell has to withstand generally lower loads than the upper shell.

[0014] According to the invention, the design and manufacturing process of the rear fuselage section is split between the upper and lower shells, for example, the manufacturing process of each of these shells is optimized in view of their respective geometry and load requirements.

[0015] Thus, one aspect of the present invention relates to a composite lower fuselage shell for a rear section of an aircraft, wherein the shell includes at least one lower skin panel and stringers formed integrally with the lower skin and extending longitudinally in the length of the aircraft (when the rear section is assembled with a complete fuselage).

[0016] The lower fuselage shell also includes frame segments extending crosswise relative to the stringers and shear ties integrally formed with one or more lower skin panels and also extending crosswise relative to the stringers. The frame segments are mechanically secured to the shear ties, for example, spacing the frame segments from the one or more lower skin panels so as to avoid the time-consuming task of riveting the frames to the skin.

[0017] By the term "integrally formed" it is meant that the stringers and shear ties are co-cured or co-bonded with the one or more skin facesheets.

[0018] The invention also relates to a rear fuselage segment comprising a composite upper fuselage shell and a lower fuselage shell as previously defined, wherein the upper and lower shells are attached to each other to jointly constitute a rear fuselage segment for an aircraft, the skin of the upper fuselage shell being internally reinforced by Omega-shaped stringers integrally formed therein, while the skin of the lower fuselage shell being internally reinforced by T-shaped stringers integrally formed therein.

[0019] Omega-shaped stringers are suitable for the highly loaded upper shell, while the lower shell, which is subject to less stress, can be strengthened with T-shaped stringers, which are easier to manufacture and are usually lighter than Omega-shaped stringers.

[0020] Preferably, the skin of the upper and lower shells are manufactured as a single panel.

[0021] The present invention also relates to a method for manufacturing a rear fuselage section of an aircraft, wherein the method comprises the following steps: manufacturing a lower fuselage shell, which includes a lower skin having an internal reinforcement structure; and manufacturing an upper fuselage shell, which includes an upper skin having an internal reinforcement structure; and wherein the lower skin is manufactured by a first technology of layered composite materials; and wherein the upper skin is manufactured by a second technology of layered composite materials different from the first technology, and the method also comprises the step of assembling the lower shell and the upper shell to jointly form the rear fuselage section.

[0022] Preferably and according to the invention, the first technology for layering composite materials is a fiber placement technology suitable for manufacturing geometrically complex composite panels, while the second technology comprises a modular technology implemented in, for example, an ATL (Automated Tape Laying) machine.

[0023] The steps of manufacturing the lower shell and the upper shell include co-curing or co-bonding T-shaped stringers to the lower skin, and co-curing or co-bonding Omega-shaped stringers to the upper skin. In addition, the steps of manufacturing the lower shell include co-curing or co-bonding shear ties to the lower skin, such as arranging the shear ties to cross the stringers, and riveting or bolting the frame segments to the shear ties, such as spacing the frame segments from the skin.

[0024] Some advantages of the present invention are as follows:

[0025] - Two different fuselage shells can be produced with different manufacturing processes, tools, etc.; allowing optimization of each process;

[0026] - Reduce the operation of riveting the lower frame segment to the lower skin panel;

[0027] - simplify the operations of pre-assembly of subassemblies such as the lower frame section to the lower skin panel;

[0028] - Improve the accuracy of overall assembly tolerance;

[0029] - Separate production and pre-assembly of upper and lower housings, which will simplify the overall process and allow for individual modifications in the future as required. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The preferred embodiments of the present invention are described below with reference to the accompanying drawings, in which:

[0031] Figure 1 A side elevation view of an aircraft according to the prior art is shown, wherein the rear fuselage section is marked as a darkened area.

[0032] Figure 2 A perspective view of a rear fuselage section according to the invention is shown. The upper and lower shells are marked in the figure. The stringers, frame segments and shear ties are shown in an enlarged detail view on the right side of the figure. The expanded view of the frame segments and shear ties is a cross-sectional view according to the longitudinal plane. DETAILED DESCRIPTION

[0033] Figure 2 The rear fuselage section 1 of a preferred embodiment is shown, which is formed by an upper fuselage shell 1a and a lower fuselage shell 1b, which are assembled to each other to jointly constitute the rear fuselage section 1. The upper fuselage shell 1a has an upper skin 4a and an Omega-shaped (Ω-shaped) stringer 5, which is integrally formed with the upper skin 4a and extends longitudinally. The frame segment 6a extends crosswise with respect to the stringer 5 and is directly fixed to the skin.

[0034] The lower fuselage shell 1b includes a lower skin 4b and a T-shaped stringer 7, which is integrally formed with the lower skin 4b and extends longitudinally. The frame segment 6b extends crosswise relative to the T-shaped stringer 7. The lower fuselage shell 1b also includes a shear tie 8 of a composite material, which is integrally formed with the lower skin 4b and extends crosswise relative to the T-shaped stringer 7. The frame segment 6b is mechanically fastened (riveted or bolted 12) to the shear tie 8, such as to space the frame segment 6b from the lower skin 4b.

[0035] Preferably, the frame segment 6b is Z-shaped.

[0036] The stringers 5 of the upper shell 1a and the stringers 7 of the lower shell 1b are co-cured or co-bonded with the upper skin 4a and the lower skin 4b. Similarly, the shear bands 8 are co-cured or co-bonded with the lower skin 4b.

[0037] The upper shell 1a has two lateral cutouts 11, 11' (eg, Figure 1 Each of these lateral cutouts 11, 11' defines a U-shaped edge having an upper edge and a lower edge and a vertical edge. Figure 2As shown, the lower housing 1b generally extends from the lower edge of one lateral cutout to the lower edge of the other cutout.

[0038] The lower skin 4 b has an access opening 9 and two longitudinally extending beams 10 which are joined to the skin to reinforce the area around the access opening 9 .

Claims

1. An aircraft rear fuselage section (1), comprising an upper fuselage shell and a lower fuselage shell (1b), the upper fuselage shell and the lower fuselage shell being attached to each other to jointly form the aircraft rear fuselage section (1), wherein: The lower fuselage shell (1b) is made of composite material and comprises at least one lower skin (4b) and a stringer (7) and a frame segment (6b), wherein the stringer (7) is integrally formed with the lower skin (4b) and extends longitudinally in the longitudinal direction of the aircraft rear fuselage segment (1), and the frame segment (6b) extends crosswise relative to the stringer (7), characterized in that the lower fuselage shell (1b) also includes a composite shear band (8), which is integrally formed with the lower skin (4b) and extends crosswise relative to the stringer (7), and wherein the frame segment (6b) is fastened (12) to the shear band (8) so that the frame segment (6b) is spaced apart from the lower skin (4b), The upper fuselage shell has an upper skin, an Ω-shaped stringer and a frame segment, the Ω-shaped stringer is formed integrally with the upper skin and extends longitudinally, and the frame segment of the upper fuselage shell crosses and extends relative to the Ω-shaped stringer. wherein the upper fuselage shell has two lateral cutouts for receiving and allowing trimming of the horizontal tail, and wherein each of the two lateral cutouts (11, 11') defines a U-shaped edge having an upper edge, a lower edge and a vertical edge; and Wherein, the lower fuselage shell (1b) substantially extends from the lower edge of one of the lateral cutouts to the lower edge of the other lateral cutout.

2. The aircraft rear fuselage segment (1) according to claim 1, wherein: The stringers and / or the shear bands of the lower fuselage shell (1b) are co-cured or co-bonded with the lower skin.

3. The aircraft rear fuselage segment (1) according to claim 1 or claim 2, wherein: The frame segments of the lower fuselage shell (1b) are riveted or bolted to the shear ties.

4. Aircraft rear fuselage segment (1) according to claim 1 or 2, wherein: The frame section of the lower fuselage shell (1b) is Z-shaped.

5. Aircraft rear fuselage segment (1) according to claim 1 or 2, wherein: The stringers of the lower fuselage shell (1b) are T-shaped.

6. Aircraft rear fuselage segment (1) according to claim 1 or 2, wherein: The lower skin has an access opening and two beams for reinforcing the area around the access opening, wherein the beams are joined to the lower skin and extend longitudinally.

7. A method for manufacturing an aircraft rear fuselage segment according to any one of claims 1 to 6, the method comprising the following steps: manufacturing the lower fuselage shell, the lower fuselage shell comprising a lower skin having an internal reinforcement structure; and manufacturing the upper fuselage shell, the upper fuselage shell comprising an upper skin having an internal reinforcement structure; and wherein the lower skin is manufactured by a first technique of layered composite materials; and wherein the upper skin is manufactured by a second technique of layered composite materials different from the first technique; and wherein the method further comprises the step of assembling the lower fuselage shell and the upper fuselage shell to together form the aircraft rear fuselage section.

8. The method according to claim 7, wherein: The first technology of the layered composite material is a fiber placement technology, and wherein the second technology includes a modular manufacturing technology.

9. The method according to claim 7 or claim 8, wherein: The steps of manufacturing the lower fuselage shell and manufacturing the upper fuselage shell include co-curing or co-bonding T-shaped stringers to the lower skin and co-curing or co-bonding Ω-shaped stringers to the upper skin.

10. The method according to claim 9, wherein: The step of manufacturing the lower fuselage shell includes: co-curing or co-bonding shear ties to the lower skin, arranging the shear ties to intersect the T-stringers, and riveting or bolting frame segments of the lower fuselage shell to the shear ties so that the frame segments of the lower fuselage shell are spaced apart from the lower skin.

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