WO2013078647A1

WO2013078647A1 - Panel,component for an airplane airfoil comprising the panel,and method for producing the panel

Info

Publication number: WO2013078647A1
Application number: PCT/CN2011/083251
Authority: WO
Inventors: Dong Liu
Original assignee: Airbus S.A.S.
Priority date: 2011-11-30
Filing date: 2011-11-30
Publication date: 2013-06-06
Also published as: CN104024105A

Abstract

The present invention relates to a panel, especially for a component having a box structure in an airplane airfoil, comprising a surface shaped body and grid-like reinforcement bars protruding from the body on one side of the body, and the body and the grid-like reinforcement bars are integral molded. Since the body and the grid-like reinforcement bars of the panel are integral molded, no additional connecting process is required, so that the disconnection phenomenon as happened between the skin and the stiffener or stringer of the prior art would not occur, and the assembly complexity can be decreased.

Description

Panel, Component for an airplane airfoil comprising the panel, and Method for producing the panel

FIELD OF THE INVENTION

The present invention relates to a panel, component having a box structure for an airplane airfoil comprising the panel, and method for producing the panel.

BACKGROUND OF THE INVENTION

In an airplane airfoil exist all kinds of components having a box structure, such as a wing, a flap, an aileron, a slat, an empennage and so on. The box structure is generally composed of a skin and spars supporting the skin. The skin is generally composed of a surface shaped metal or composite panel, and is connected with the spars through fasteners (e.g. rivets) or by means of boding.

During the operation and service of the airplane, the components having a box structure are subject to a shear force and prone to buckling due to its size, so that the stability thereof is reduced. On the other hand, during the takeoff and landing of the airplane, the skin of the airplane airfoil (especially a flap trailing edge) is often subject to the impact of such as stones and so on, thus dents can be formed on the skin surface. If the dents are too large or too deep, not only the mechanical performance of the airplane during flight is influenced, but also the aesthetic appearance of the airplane is decreased.

In order to improve the stability and damage tolerance of the components having a box structure, stiffeners or stringers can be arranged on the skin. The stiffeners or stringers may be connected with the skin by means of bonding. The stiffeners or stringers may have different shapes, such as "τ" > " I " "Π" and so on. The stiffener or stringer generally comprises a web and a flange. Additionally, ribs may be arranged on the web of the stiffener or stringer, so as to further improve the strength of the skin.

However, during the takeoff or service of the airplane, due to the impact of such as stones, air flow, even a tool which is accidentally dropped off, cracks may be generated between the skin and the stiffener or stringer, so that a disconnection phenomenon (such as debonding) would occur. Furthermore, such stiffeners or stringers are generally arranged in only one direction (i.e. longitudinal direction of the skin), so the strength of the skin can be improved in only one direction, and the skin cannot be subject to complex load. In addition, due to the additional stiffeners or stringers, this method not only increases the manufacturing costs, but also raises the assembly complexity.

Additionally, in order to improve the strength of the components having a box structure, honeycomb fills or ribs can be disposed inside of the box structure. However, the honeycomb fills or ribs can both raise the assembly complexity of the box structure and increase the manufacturing costs.

Further, in the components having a box structure (e.g. a flap trailing edge) with a small space, it is difficult to add such honeycomb fills or ribs.

SAMMURY OF THE INVENTION

The present invention is based on the object of providing a panel, especially for a component having a box structure in an airplane airfoil, which replaces the skin of the component having a box structure, so that no stiffener or stringer is required, and which has a high stability and a strong damage tolerance.

In order to achieve the object of the invention, a panel, especially for a component having a box structure in an airplane airfoil, is provided, which comprises a surface shaped body and grid-like reinforcement bars protruding from the body on one side of the body, and the body and the grid-like reinforcement bars are integral molded. Since the body and the grid-like reinforcement bars of the panel are integral molded, no additional connecting process is required, so that the disconnection phenomenon as happened between the skin and the stiffener or stringer of the prior art would not occur, and the assembly complexity can be decreased. It is particularly advantageous that the panel according to the disclosure is applied to a component having a box structure with a small space (e.g. a flap trailing edge), because the honeycomb fills or ribs arranged inside of the box structure mentioned in the background part would be not required any more.

Preferably, the panel is composed of a composite material. Particularly preferably, the composite material comprises reinforcement fibers and a matrix, and the reinforcement fibers are continuously arranged in the direction of the reinforcement bars. Thus, the panel can have an improved strength. The composite material may be for example Carbon Fiber Reinforcement Plastic (CFRP), with the matrix being epoxy resin, bismaleimide resin, thermosetting resin, or thermoplastic resin and so on.

Preferably, the grid-like reinforcement bars comprise a plurality of first reinforcement bars extending in a first direction and a plurality of second reinforcement bars extending in a second direction crossing the first direction. Particularly preferably, the plurality of first reinforcement bars extend on the entire body in a first spacing separated from each other in the horizontal direction, and the plurality of second reinforcement bars extend on the entire body in a second spacing separated from each other in the vertical direction. Here, according to the load subjected in the first and second directions, the first spacing can be selected to be equal to or different from the second spacing. Based on this solution, the reinforcement bars can improve the strength of the panel in at least two directions, so that the stability and damage tolerance of the panel are improved.

Preferably, the grid-like reinforcement bars further comprise a plurality of third reinforcement bars extending in a third direction crossing the first and second directions. Particularly preferably, the plurality of first reinforcement bars extend on the entire body in a first spacing separated from each other in the direction at a first angle inclined with respect to the horizontal direction, the plurality of second reinforcement bars extend on the entire body in a second spacing separated from each other in the direction at a second angle inclined with respect to the horizontal direction, and the plurality of third reinforcement bars respectively extend on the entire body through the crossing points between the plurality of first reinforcement bars and the plurality of second reinforcement bars. Based on this solution, the reinforcement bars can improve the strength of the panel in at least three directions, so that the stability and damage tolerance of the panel are improved.

Particularly preferably, the grid-like reinforcement bars are configured as an isogrid or an orthogrid. In particular, when the grid-like reinforcement bars are configured as an isogrid, the strength of the grid can be uniformly improved in every direction, so that the stability and damage tolerance of the panel are improved.

Preferably, the panel on its side having the grid-like reinforcement bars faces the internal of the box structure.

The invention also provides a component having a box structure in an airplane airfoil, which comprises a front spar, a closure end and a skin, characterized in that the skin is composed of the above panel. Preferably, the component is a wing, a flap, an aileron, a slat, an empennage or the constitution parts thereof, such as a flap trailing edge.

In addition, the invention further provides a method of making the above panel, the panel being composed of a composite material, which comprises steps: a pre-form of reinforcement fibers is formed through a 3D braid technology in a cavity of mold; a liquid resin as matrix material is injected into the closed cavity; and the liquid resin is cured.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will be explained in detail below with reference to the drawings, in which:

FIG. 1 shows a schematic view of a flap trailing edge of an airplane; FIGs. 2A and 2B shows a perspective view and a plan view of the panel according to a first embodiment of the invention, respectively;

FIGs. 3A and 3B shows a perspective view and a plan view of the panel according to a second embodiment of the invention, respectively.

DETAILED DESCRIPTION OF THE DRAWINGS

Hereinbelow, the panel according to the disclosure is described through a panel for a flap trailing edge in an airplane airfoil as a preferred embodying form. It should be noticed that the flap trailing edge is merely exemplary, and the following described embodying form does not limit the invention. The panel according to the disclosure can be applied to the components having a box structure in an airplane airfoil, e.g. a wing, a flap, an aileron, a slat, an empennage or the constitution parts thereof, such as a flap trailing edge.

The flap comprises a flap body and a trailing edge. Referring to Fig. 1, a flap trailing edge comprises an upper skin 10, a lower skin 20, a front spar 30 and a closure end 40. The upper skin 10 and the lower skin 20 respectively cover the upper and lower side of the front spar 30 and the closure end 40, so as to form a box structure.

Figs. 2 and 3 respectively show a panel according to the embodiment of the invention replacing the upper skin 10 or the lower skin 20.

Referring to Figs. 2 A and 2B, the panel 100 according to the first embodiment comprises a surface shaped body 110 and grid-like reinforcement bars protruding, advantageously towards the internal of the box structure, from the body 110 on one side of the body. The body 110 and the grid-like reinforcement bars are integral molded. In this embodiment, the body 110 and the grid-like reinforcement bars are both composed of a composite material. Such composite material may comprise reinforcement fibers and a matrix, and the reinforcement fibers are continuously arranged in the direction of the reinforcement bars. The composite material may be for example CFRP, with the matrix being epoxy resin, bismaleimide resin, thermosetting resin, or thermoplastic resin and so on, and is manufactured for example through a liquid composite molding (LCM) technology. The LCM technology is a manufacture technology of the composite material in which a liquid polymer is injected into a closed cavity of mold with a fiber pre-form, or a fiber film previously placed into a cavity of mold is thermal melted, and then the liquid polymer infiltrates the fiber and cures while flowing and filling into the cavity of mold. In particular, a pre-form of reinforcement fibers is formed through a 3D braid technology in a cavity of mold; a liquid resin as matrix material is injected into the closed cavity; and the liquid resin is cured, so as to form the panel according to the disclosure. The strength of the panel made by this technology can be further improved especially in the direction of thickness, because the body and the reinforcement bars protruding from the body of the panel can be connected with each other through the fibers.

The grid-like reinforcement bars may comprise a plurality of first reinforcement bars 120 extending in a first direction and a plurality of second reinforcement bars 130 extending in a second direction crossing the first direction. In this embodiment, the plurality of first reinforcement bars 120 extend on the entire body 110 in a first spacing separated from each other in the horizontal direction, and the plurality of second reinforcement bars 130 extend on the entire body 110 in a second spacing separated from each other in the vertical direction. That is, the grid-like reinforcement bars are configured as an orthogrid. In addition, the first spacing may be equal to or different from the second spacing.

When the skin is replaced with the panel according to this embodiment in the component having a box structure in an airplane airfoil, on one hand, the stability and damage tolerance of the panel is increased due to the grid-like reinforcement bars in the panel, so that no stiffeners or stringers are required any more, and off course the disconnection phenomenon would not occur. On the other hand, the grid-like reinforcement bars in the panel can improve the stability of the panel in at least two directions, so as to improve the capability of the panel subjecting to the load.

Referring to Figs. 3A and 3B, a panel 200 according to a second embodiment of the invention comprises a surface shaped body 210 and grid-like reinforcement bars protruding, advantageously towards the internal of the box structure, from the body 210 on one side of the body. The material and connecting manner of the body 210 and the grid-like reinforcement bars are the same as those of the body 110 and the grid-like reinforcement bars in the first embodiment. The panel 200 according to the second embodiment of the invention differs from the panel 100 according to the first embodiment of the invention in the arrangement of the grid-like reinforcement bars.

In the second embodiment, the grid-like reinforcement bars may comprise a plurality of first reinforcement bars 210 extending in a first direction, a plurality of second reinforcement bars 220 extending in a second direction crossing the first direction, and a plurality of third reinforcement bars 240 extending in a third direction crossing the first and second directions. The plurality of first reinforcement bars 220 may extend on the entire body 210 in a first spacing separated from each other in the direction at a first angle inclined with respect to the horizontal direction, the plurality of second reinforcement bars 230 may extend on the entire body 210 in a second spacing separated from each other in the direction at a second angle inclined with respect to the horizontal direction, and the plurality of third reinforcement bars 240 may respectively extend on the entire body 210 through the crossing points between the plurality of first reinforcement bars 220 and the plurality of second reinforcement bars 230. In this embodiment, the plurality of first reinforcement bars 220 may extend on the entire body 210 in a first spacing separated from each other in the direction at 150° inclined with respect to the horizontal direction, the plurality of second reinforcement bars 230 may extend on the entire body 210 in a second spacing separated from each other in the direction at 30° inclined with respect to the horizontal direction, and the plurality of third reinforcement bars 240 may respectively extend on the entire body 210 in the vertical direction, wherein the first spacing is equal to the second spacing. That is, the grid-like reinforcement bars are configured as an isogrid.

In this embodiment, because the grid-like reinforcement bars are configured as an isogrid, the stability of the panel can be uniformly improved in every direction, so as to improve the capability of the panel subjecting to the load.

In addition, regarding to the spacing and angle in the above embodiments, they can be selected according to the practical situation of the components using the panel (such as the stressed direction, the size of the components).

In addition, the grid of the grid-like reinforcement bars in the panel of the invention is not limited to the above shapes, but can be selected as any proper shape according to the practical situation, e.g. a honeycomb shape.

The panel according to the disclosure is applicable to the components having a box structure in an airplane airfoil with a small space, which is difficult to be assembled stiffeners or stringers and difficult to add honeycomb fills or ribs, such as a flap trailing edge. For example, such components may be a wing, a flap, an aileron, a slat, an empennage or the constitution parts thereof, such as a flap trailing edge.

Although the invention has been described by way of example and with reference to particular embodiments it is to be understood that modification and/or improvements may be made without departing from the scope of the appended claims.

Where in the foregoing description reference has been made to integers or elements having known equivalents, then such equivalents are herein incorporated as if individually set forth. LIST OF REFERENCE NUMERALS

1 flap

2 trailing edge

10 upper skin

20 lower skin

30 front spar

40 closure end

50 rib

100, 200 panel

110, 210 body

120, 220 first reinforcement bars 130, 230 second reinforcement bars 240 third reinforcement bars

Claims

1. A panel, especially for a component having a box structure in an airplane airfoil, comprising a surface shaped body and grid-like reinforcement bars protruding from the body on one side of the body, and the body and the grid-like reinforcement bars are integral molded.

2. A panel according to claim 1, characterized in that the panel is composed of composite material.

3. A panel according to claim 2, characterized in that the composite material comprises reinforcement fibers and a matrix, and the reinforcement fibers are continuously arranged in the direction of the reinforcement bars.

4. A panel according to any one of previous claims, characterized in that the grid-like reinforcement bars comprise a plurality of first reinforcement bars extending in a first direction and a plurality of second reinforcement bars extending in a second direction crossing the first direction.

5. A panel according to claim 4, characterized in that the plurality of first reinforcement bars extend on the entire body in a first spacing separated from each other in the horizontal direction, and the plurality of second reinforcement bars extend on the entire body in a second spacing separated from each other in the vertical direction.

6. A panel according to claim 4, characterized in that the grid-like reinforcement bars further comprise a plurality of third reinforcement bars extending in a third direction crossing the first and second directions.

7. A panel according to claim 6, characterized in that the plurality of first reinforcement bars extend on the entire body in a first spacing separated from each other in the direction at a first angle inclined with respect to the horizontal direction, the plurality of second reinforcement bars extend on the entire body in a second spacing separated from each other in the direction at a second angle inclined with respect to the horizontal direction, and the plurality of third reinforcement bars respectively extend on the entire body through the crossing points between the plurality of first reinforcement bars and the plurality of second reinforcement bars.

8. A panel according to any one of previous claims, characterized in that the grid-like reinforcement bars are configured as an isogrid or an orthogrid.

9. A panel according to any one of previous claims, characterized in that the panel on its side having the grid-like reinforcement bars faces the internal of the box structure.

10. A component having a box structure in an airplane airfoil, comprising a front spar, a closure end and a skin, characterized in that the skin is composed of the panel according to any one of claims 1-9.

11. A component according to claim 10, characterized in that the component may be a wing, a flap, an aileron, a slat, an empennage or the constitution parts thereof, such as a flap trailing edge.

12. A method for producing the panel according to claim 1, the panel being composed of a composite material, comprising steps: a pre-form of reinforcement fibers is formed through a 3D braid technology in a cavity of mold; a liquid resin as matrix material is injected into the closed cavity; and the liquid resin is cured.