WO2013078646A1

WO2013078646A1 - Airplane component having a box structure

Info

Publication number: WO2013078646A1
Application number: PCT/CN2011/083249
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

Abstract

The present invention relates to an airplane component having a box structure, comprising skin and framework, wherein the framework comprises at least one spar extending in the longitudinal direction of the airplane component, the spar being configured as a waved spar. The airplane component according to the invention has a lighter weight when meeting the same condition of stability.

Description

Airplane component having a box structure

FIELD OF THE INVENTION

The present invention relates to an airplane component having a box structure , especially a wing, a flap, an aileron, an empennage (HTP, VTP, Rudder, Elevator) or the constitution parts thereof, such as a flap trailing edge and so on.

BACKGROUND OF THE INVENTION

The trailing edge of flap of an airplane generally consists of a framework and skin. The framework may comprise a plurality of spars, ribs and stringers. The framework and the skin of the trailing edge of flap form a box structure.

The basic stressed parts of the trailing edge of flap comprise longitudinal (in the direction of the wing span) framework, transversal (in the direction of air flow) framework and skin. A longitudinal framework comprises spars and stringers, and a transversal framework comprises ribs.

During the flight of the airplane, the skin is directly subject to the air dynamic load, and transfers it to the longitudinal and transversal frameworks. When imparted with the air dynamic load, the spar, as a longitudinal stressed part, would be subjected to compressive force, tensile force, shear force and bending moment.

In a traditional spar is configured as a straight spar and the spar web is plane. The flange of spar is mostly subject to compressive force or tensile force, while the spar web is subjected to compressive force, tensile force, shear force and bending moment, therefore stiffener is adopted to increase the stability of spar web.

In the prior art, in order to be capable of bearing the loads generated during the flight of the airplane, the component having a box structure, for example the trailing edge of flap, often employs a multi-spar structure, which increases the weight of the component, leading to the increase of the weight of the entire airplane, which is disadvantageous for the economy of the fuel of the airplane.

SAMMURY OF THE INVENTION

The present invention is based on the object of providing an airplane component having a box structure, which has a lower weight when meeting the same stability.

This object of the invention is solved by an airplane component having a box structure, which comprises skin and a framework, wherein the framework comprises at least one spar extending in the longitudinal direction of the airplane component, the spar being configured as a waved spar.

The idea of the invention is that: a traditional straight spar of the airplane component, especially the trailing edge of flap, is replaced by a waved spar. Compared with the traditional straight spar, the waved spar has a larger bending stiffness (moment of inertia), therefore the waved spar can achieve a larger stability. Therefore, when meeting the same level of the stability, the thickness of spar web can be reduced, and the number of stiffener of spar web can be reduced. Moreover, another advantage of the waved spar is that, the waved spar can provide a better support to the skin than the straight spar, therefore the number of waved spars can be smaller than the number of straight spars. For example, after calculating the stability of skin of a flap trailing edge, it is fund that, for the same load, three straight spars can be replaced by two waved spars. Therefore, the waved spar has a better structure efficiency than the straight spar.

Preferably, the waved spar has a shape of a sinusoidal wave. With respect to a tooth wave and a trapezoidal wave, the sinusoidal wave has the biggest area-length ratio, thus in the case of the same length, the waved spar with a sinusoidal shape can obtain the biggest bending stiffness (moment of inertia), that is, the stability can be maximally achieved. Therefore, the waved spar with a sinusoidal shape has optimal structure efficiency.

Preferably, a plurality of waved spars are provided, all of which having the same wave shape. This can thus simplify the manufacture of the waved spar.

Preferably, the phase position of two adjacent waved spars is disposed so that the peak position of one of them just corresponds to the valley position of the other of them. Thereby, a larger support area to the skin can be achieved, that is, a better support to the skin can be achieved.

Preferably, the waved spar is made of composite material. Particularly preferably, the airplane component with waved spars, such as trailing edge of flap, is integrally molded using liquid composite molding (LCM) technology in a single process. This can thus avoid the complicated installation.

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 wing;

FIG. 2 shows a perspective view of an airplane component having a box structure according to an embodiment of the invention with upper skin being removed.

DETAILED DESCRIPTION OF THE DRAWINGS

Herein below, the airplane component having a box structure according to the disclosure is described through a flap trailing edge for an airplane wing 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 airplane component having a box structure according to the disclosure can be wing, flap, aileron, empennage (HTP, VTP, Rudder, Elevator) or the constitution parts thereof and so on. Referring to Fig. 1, a flap trailing edge 1 comprises an upper skin, a lower skin, a front spar and a closure end. The upper skin and the lower skin respectively cover on the top and bottom of the front spar and the closure end, so as to form a box structure.

Fig. 2 shows a perspective view of the flap trailing edge according to Fig. 1 with the upper skin being removed. It can be seen from Fig. 2, inside of the flap trailing edge is disposed two waved spars 2 extending in the longitudinal direction of the flap trailing edge. The two waved spars 2 are disposed a distance spaced from each other. The two waved spars 2 have the same wave shape, that is, they have the same wave amplitude and frequency. However, the phase positions of the two waved spars 2 are misaligned to each other in an angle, so that the peak position of the upper waved spar just corresponds to the valley position of the lower waved spar, thus a better support to the skin can be achieved.

The shape of the waved spar may be a sinusoidal wave, a tooth wave and a trapezoidal wave. In this embodiment of the invention, the waved spar is configured as a sinusoidal wave. With respect to a tooth wave and a trapezoidal wave, the sinusoidal wave has the biggest area-length ratio, thus in the case of the same length, the waved spar with a sinusoidal shape can obtain the biggest bending stiffness (inertia moment), that is, the stability can be maximally achieved. Therefore, the waved spar with a sinusoidal shape has optimal structure efficiency.

The waved spar is particularly applicable to the airplane component having a box structure which has a small inner space, such as a flap trailing edge. Since the subjected load is small, only two waved spars are needed to be disposed in the inner space of the flap trailing edge, without disposing additional ribs, stringers and honeycomb fills and so on.

Preferably, the waved spar is made of composite material. Particularly preferably, the box structure with waved spars such as trailing edge of flap is manufactured using liquid composite molding (LCM) technology. 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 flap trailing edge

waved spars

Claims

1. An airplane component having a box structure, comprising skin and framework, wherein the framework comprises at least one spar extending in the longitudinal direction of the airplane component, characterized in that the spar is configured as a waved spar.

2. An airplane component according to claim 1, characterized in that the waved spar has a shape of a sinusoidal wave.

3. An airplane component according to any one of previous claims, characterized in that a plurality of waved spars are provided, all of which having the same wave shape.

4. An airplane component according to claim 3, characterized in that the phase position of two adjacent waved spars is disposed so that the peak position of one of them just corresponds to the valley position of the other of them.

5. An airplane component according to any one of previous claims, characterized in that the airplane component is wing, flap, aileron, empennage (HTP, VTP, Rudder, Elevator) or the constitution parts thereof, such as trailing edge of flap.

6. An airplane component according to any one of previous claims, characterized in that the waved spar is made of composite material.

7. An airplane component according to claim 6, characterized in that the airplane component is integrally molded using liquid composite molding technology in a single process.