METHOD FOR MANUFACTURING A STRUCTURAL ELEMENT FOR A FUSELAGE OF AN AIRCRAFT

Abstract

A method for manufacturing a structural element for a fuselage of an aircraft. To improve the manufacture of structural elements, a method includes laying up textile material members on a mandrel to form a plurality of structural element preforms that are space apart along an extended direction of the mandrel. The structural element preforms form closed loops and are subsequently cured to obtain annular structural elements. The annular structural elements are used as basic building blocks for stiffening panel members or are directly used as structural frame elements reinforcing cut-outs in a fuselage for windows and/or doors.

Claims

1. A method for manufacturing a structural element for a fuselage of an aircraft, the method comprising steps of: a) on a mandrel that extends in a longitudinal direction, laying up a plurality of textile material members to form at least one structural element preform next to each other; and b) curing the structural element preform, to obtain a structural element.

2. The method according to claim 1, wherein in step a) the textile material members are layed up on the mandrel such that a plurality of structural element preforms are spaced apart along the longitudinal direction.

3. The method according to claim 1, wherein the mandrel is a split mandrel or half-size mandrel.

4. The method according to claim 1, wherein the textile material members are layed up on a circumferential surface of the mandrel to form a closed loop structural element preform, and in step b) the structural element preforms are cured to obtain an annular structural element.

5. The method according to claim 1, wherein in a step c) the mandrel is removed by pulling off the structural elements from the mandrel or by moving separate portions of the mandrel relative to each other.

6. The method according to claim 1, wherein in step a) the laying up is done by winding around the mandrel, automated fiber placement, automated tape layering of the textile material members.

7. The method according to claim 1, wherein the textile material members are selected from the group consisting of textile material, fiber composite material, tows, slit tape, fiber tape, non-crimp fabric, non-woven fabric, and prepregs.

8. The method according to claim 1, wherein in step b) at least one structural element preform is layed up by laying up the textile material members on the mandrel such that the structural element preform is double curved, wherein a first curvature is formed by continuously displacing the textile material members during laying up along a longitudinal axis up to a maximum displacement, and a second curvature is formed by laying up the textile material members around a circumferential surface of the mandrel.

9. The method according to claim 8, wherein the first curvature is further formed by continuously displacing the textile material members during laying up in an opposite direction along the longitudinal axis from the maximum displacement until the textile material members form a closed loop structural element preform.

10. A method for manufacturing a structural frame element for a cut-out in a fuselage of an aircraft, the method comprising a step of performing a method according to claim 4 such that an annular structural element is formed that is configured to be arranged to surround the cut-out in the fuselage and to be arranged on a skin or in between skins of the fuselage.

11. A method for manufacturing a stiffened structural panel element of an aircraft, the method comprising steps of: a) performing the method according to claim 4 such that at least one annular structural elements is produced, the annular structural element extending along an element axis and circumferentially surrounding the element axis; b) providing a panel member; and c) affixing the annular structural element to the panel member to obtain the structural panel element.

12. The method according to claim 11, wherein in step c) the annular structural elements are affixed to form a structural grid.

13. The method according to claim 11, wherein in step c) the annular structural elements are affixed so that adjacent annular structural elements engage each other at an engagement location, and the annular structural elements are fixed to each other at the engagement locations.

14. The method according to claim 13, wherein the annular structural elements are affixed to the panel member by bonding, welding or bolting, and/or the annular structural elements are fixed to each other by bonding, welding or bolting.

15. A structural frame element or a stiffened structural panel element obtained by the method according to claim 10.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Embodiments of the disclosure herein are described in more detail with reference to the accompanying schematic drawings that are listed below.

[0040] FIG. 1 depicts an embodiment of a method for manufacturing a stiffened structural panel element;

[0041] FIG. 2 depicts a variant of a stiffened structural panel element;

[0042] FIG. 3 depicts another variant of a stiffened structural panel element;

[0043] FIG. 4 depicts a joint between a structural element and a panel;

[0044] FIG. 5 depicts a joint between another structural element and the panel; and

[0045] FIG. 6 depicts an embodiment of a structural frame element.

DETAILED DESCRIPTION

[0046] As depicted in FIG. 1, in a first step a plurality of textile material members are layed up on a mandrel 10. The mandrel 10 extends in a longitudinal direction (left-right direction in FIG. 1). The mandrel 10 has a circumferential surface 12 that is a forming surface for the textile material members. The textile material members may be tows or slit tape that is wound around the mandrel 10 or applied to the circumferential surface 12.

[0047] The textile material members are layed up in such a way that a plurality of structural element preforms 14 are generated. The structural element preforms 14 are spaced apart along the longitudinal direction. The structural element preforms 14 can be double curved.

[0048] A first curvature is formed by continuously displacing the textile material members along the longitudinal direction up to a maximum displacement d. In other words, the textile material members are progressively arranged outside of a cross-sectional plane 16 through the mandrel 10 that is orthogonal to the longitudinal direction until a desired maximum is reached. After that the textile material members are progressively brought back so that as a result the structural element preform 14 forms a closed loop 18.

[0049] A second curvature is formed by the circumferential surface 12 of the mandrel 10.

[0050] In a second step, the structural element preforms 14 are subsequently cured in order to obtain annular structural elements 20 that are suitable for reinforcing. The annular structural elements 20 extend along an element axis 22 which is also called height h. The annular structural elements 20 surround the element axis 22 in a circumferential direction.

[0051] Finally, the structural elements 20 are affixed to a panel member 24 such that the structural elements 20 form a structural grid 26. The structural elements 20 therefore are able to act as stiffening elements for the panel member 24. The structural elements 20 are arranged so that they engage each other at certain engagement locations 28. The structural elements 20 are fixed to each other at these engagement locations 28. As a result, a stiffened structural panel element 30 is obtained that may be used for manufacturing a fuselage or various doors of an aircraft.

[0052] As depicted in FIG. 2, a variant of the stiffened structural panel element 30 comprises structural elements 20 having substantially rectangular cross-section. Other configurations, including double curved configurations are possible.

[0053] As depicted in FIG. 3, a variant of the stiffened structural panel element 30 may have structural elements 20 that have different height h. A larger structural element 32 may serve as a mount point for struts and other elements that are typically used in a fuselage. The larger structural element 32 has also a larger height H compared to the structural elements 20.

[0054] As depicted in FIG. 4, the structural element 20 can be affixed to the panel member 24 by an adhesive that forms a filler 34.

[0055] As depicted in FIG. 5, the structural element 20 may be manufactured with a flange portion 36. Adjacent structural elements 20 can be affixed to the panel member 24 by introducing adhesive into a cavity 38 defined between the adjacent structural elements 20 and the panel member 24. It is also possible to bolt the flange portions 36 to the panel member 24.

[0056] FIG. 6 depicts a structural frame element 40 that is also obtainable by the method described before. The structural frame element 40 may be a window frame or door frame that is installed in a fuselage to reinforce the cut-outs. The structural frame element 40 is double curved.

[0057] In order to improve the manufacture of structural elements (20), the disclosure herein proposes to lay up textile material members on a mandrel (10) so as to form a plurality of structural element preforms (14) that are space apart along an extended direction of the mandrel (10). The structural element preforms (14) form closed loops (18) and are subsequently cured to obtain annular structural elements (20). The annular structural elements (20) are used as basic building blocks for stiffening panel members (24) or are directly used as structural frame elements (40) reinforcing cut-outs in a fuselage for windows and/or doors.

[0058] While at least one example embodiment of the present invention(s) is disclosed herein, it should be understood that modifications, substitutions and alternatives may be apparent to one of ordinary skill in the art and can be made without departing from the scope of this disclosure. This disclosure is intended to cover any adaptations or variations of the example embodiment(s). In addition, in this disclosure, the terms “comprise” or “comprising” do not exclude other elements or steps, the terms “a”, “an” or “one” do not exclude a plural number, and the term “or” means either or both. Furthermore, characteristics or steps which have been described may also be used in combination with other characteristics or steps and in any order unless the disclosure or context suggests otherwise. This disclosure hereby incorporates by reference the complete disclosure of any patent or application from which it claims benefit or priority.

LIST OF REFERENCE SIGNS

[0059] 10 mandrel [0060] 12 circumferential surface [0061] 14 structural element preform [0062] 16 cross-sectional plane [0063] 18 closed loop [0064] 20 annular structural element [0065] 22 element axis [0066] 24 panel member [0067] 26 structural grid [0068] 28 engagement location [0069] 30 stiffened structural panel element [0070] 32 larger structural element [0071] 34 filler [0072] 36 flange portion [0073] 38 cavity [0074] 40 structural frame element [0075] d maximum displacement [0076] h height