CN111268092B

CN111268092B - Structure for improving torsional rigidity of trailing edge structure of flexible wing

Info

Publication number: CN111268092B
Application number: CN202010102170.6A
Authority: CN
Inventors: 周丽; 夏佳辉; 邱涛
Original assignee: Nanjing University of Aeronautics and Astronautics
Current assignee: Nanjing University of Aeronautics and Astronautics
Priority date: 2020-02-19
Filing date: 2020-02-19
Publication date: 2023-01-06
Anticipated expiration: 2040-02-19
Also published as: CN111268092A

Abstract

The invention discloses a structure for improving torsional rigidity of a flexible wing trailing edge structure, belonging to the field of structural design of a morphing aircraft. The supporting plate is a connecting structure of a wing non-deformation structure and a trailing edge flexible structure, and the trailing edge of the whole flexible wing is supported by the supporting plate; the web supports the flexible skin and supports the distributed drive; the honeycomb-like torsion-resistant structure connects the support plate, each web plate and the rear end dimensional body in sequence; the flexible skin is connected between the adjacent webs, and the distributed driving device is connected between the adjacent webs and is connected with the flexible skin; the web plate is used for supporting the flexible skin and the distributed driving device, and a honeycomb-like anti-torsion structure is adopted, so that the problem of insufficient anti-torsion rigidity of the deformable trailing edge part of the wing is solved, and the anti-torsion capability of the trailing edge structure of the flexible wing is improved.

Description

Structure for improving torsional rigidity of trailing edge structure of flexible wing

Technical Field

The invention belongs to the field of structural design of a morphing aircraft, relates to a flexible wing trailing edge structure, and particularly relates to a structure for improving torsional rigidity of the flexible wing trailing edge structure.

Background

The morphing aircraft can change the shape layout and maintain the optimal aerodynamic performance in different flight environments and flight tasks. The trailing edge variable camber wing can delay aerodynamic separation of the wing surface, improve lift-drag ratio and improve aerodynamic efficiency of the airplane under different flight requirements. If a large deformation is required to be obtained on the trailing edge of the flexible wing, a flexible skin is usually adopted, and the structural rigidity and the bearing capacity can be greatly changed. After the bending load born by the skin is borne by the driver, the capability of resisting shearing and torsion is greatly reduced. There are many designs that add core plates to the structure to withstand the shear and torque at the trailing edge. The core plate has low structural efficiency and brings great weight increase to the wing.

Disclosure of Invention

Aiming at the problems in the prior art and the problem of insufficient torsional rigidity of the deformable trailing edge part of the wing, the invention provides a novel structure design method, wherein a web plate is used for supporting a flexible skin and a distributed driving device, and a honeycomb-like torsional structure is adopted, so that the torsional resistance of the trailing edge structure of the flexible wing is improved.

The invention is realized in the following way:

a structure for improving torsional rigidity of a flexible wing trailing edge structure comprises a wing non-deformation structure and a trailing edge flexible structure, wherein the wing non-deformation structure and the trailing edge flexible structure are connected through a supporting plate; the trailing edge flexible structure comprises a plurality of groups of webs which are longitudinally arranged, distributed driving devices are arranged at the top ends between the adjacent webs, flexible skins cover the outer sides of the distributed driving devices, and the distributed driving devices drive the flexible skins to extend or compress along the chord direction to realize the upward or downward deflection of the trailing edge flexible structure; the supporting plates and the web plates and the groups of web plates are connected in sequence through honeycomb-like anti-torsion structures, the honeycomb-like anti-torsion structures are folded into triangular meshes by thin plates, and the folding line direction is parallel to the wingspan direction. The torsional stiffness of the structure is varied in the present invention by the shape of the cells of the honeycomb-like torsional stiffness structure, the cell density, and the thickness of the honeycomb-like wall plate. Firstly, assuming that a shear resisting plate is arranged on the middle plane of the trailing edge structure to resist the aerodynamic load borne by the trailing edge of the wing, and the thickness of the required shear resisting plate, making the total material amount of the shear resisting plate into a honeycomb-like structure, optimizing the shape and size of a honeycomb-like grid, and determining the thickness and shape parameters of a wall plate of the grid.

Further, the flexible skin is connected between adjacent webs, the flexible skin is supported by the webs, and the distributed drive apparatus is supported by the webs. The anti-torsion capability of the flexible rear edge is improved by adopting a honeycomb-like structure, and the flexible skin is supported by a web plate in the forward direction.

Furthermore, the support plate is provided with T-shaped flanges at the positions of the upper wing surface and the lower wing surface, the front faces of the T-shaped flanges along the chord direction are connected with the wing skins, the rear faces of the T-shaped flanges are connected with the flexible skins, and under the driving of the distributed driving device, the rear edge flexible structure changes the bending degree upwards or downwards. The flexible skin has certain out-of-plane rigidity, and is not deformed along the wingspan direction and is deformed along the chord direction.

Furthermore, the web is provided with T-shaped flanges at the upper and lower wing positions, the transverse edges of the T-shaped flanges are connected with the flexible skin, and the vertical edges of the T-shaped flanges are connected with the distributed driving device.

Furthermore, the trailing edge flexible structure also comprises a rear end dimensional body connected with the tail end.

Furthermore, the distributed driving device adopts a fiber reinforced sealed flexible cavity.

Further, the triangular meshes in the honeycomb-like torsion-resistant structure have equal or unequal triangular side lengths.

The beneficial effects of the invention and the prior art are as follows:

the bearing structure of the trailing edge of the flexible wing is formed by the honeycomb-like structure and the web plate, the web plate is used as a support of the flexible skin and an installation support structure of the driver, the honeycomb-like structure is used for resisting shear force and torque, bending load is balanced by the flexible skin and the distributed driving device, the defect that the torsional rigidity of the deformable trailing edge part of the wing is insufficient is overcome, and the torsional capacity of the trailing edge structure of the flexible wing is improved;

the webs are connected by the honeycomb-like anti-torsion structure, so that the overall structural stability is improved, and the anti-torsion capability of the deformable rear edge is enhanced; due to the supporting and stabilizing functions of the honeycomb-like grids, the utilization rate of the material is improved; after the original shear-resistant core plate is changed into a honeycomb-like supporting structure, the torsion resistance and shear resistance of the section are improved, and the structure still has good deflection capability.

Drawings

FIG. 1 is a schematic view of a structure for increasing torsional stiffness of a trailing edge structure of a flexible wing in accordance with the present invention;

FIG. 2 is a schematic view of a honeycomb-like anti-torsional structure for increasing the torsional stiffness of a trailing edge structure of a flexible wing in accordance with the present invention;

FIG. 3 is a diagram of a torsional displacement cloud using a honeycomb-like structure in an embodiment of the present invention;

FIG. 4 is a cloud view of torsional displacement with only shear core plates in an embodiment of the invention;

the airplane wing structure comprises a support plate 1, a web plate 2, a rear end dimension body 3, a honeycomb-like anti-torsion structure 4, a flexible skin 5, a distributed driving device 6, a wing non-deformation structure 7 and a rear edge flexible structure 8.

Detailed Description

In order to make the objects, technical solutions and effects of the present invention more clear, the present invention is further described in detail by the following examples. It should be noted that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

As shown in fig. 1, the trailing edge structure of the flexible wing of the invention is composed of a support plate 1, a web 2, a rear end dimensional body 3, a honeycomb-like anti-torsion structure 4, a flexible skin 5 and a distributed drive device 6. The supporting plate 1 is a connecting structure of the wing non-deformation structure 7 and the trailing edge flexible structure 8, and the trailing edge of the whole flexible wing is supported by the supporting plate 1; the web 2 supports a flexible skin 5 and supports a distributed drive 8; the honeycomb-like torsion-resistant structure 4 connects the support plate 1, each web 2 and the rear end dimensional body 3 in succession; a flexible skin 5 is connected between adjacent webs 2 and a distributed drive 5 is connected between adjacent webs, which is connected to the flexible skin 5.

Specific examples of using the mechanism of the present invention are as follows:

assuming that a shear-resistant core plate is arranged on the middle plane of the trailing edge structure, the maximum shearing force of the chord-direction section is calculated according to the aerodynamic load borne by the trailing edge of the wing, the thickness of the core plate required for resisting the shearing force is determined, and the total amount of materials required for resisting the shearing force is obtained on the basis of the thickness (with a certain amplification factor). The materials are made into a honeycomb-like structure, and the honeycomb-like torsional structure with the largest torsional rigidity and the smallest bending rigidity is obtained through optimization of grid shape and size.

In this example, a NACA0012 airfoil is used, with a chord length of 1500mm, followed by a 500mm compliant trailing edge portion, with a span in the spanwise direction of 200 mm. The wing non-deformation structure 7 and the trailing edge flexible structure 8 are connected through the supporting plate 1, the thickness is 5mm, and the height is 57.035mm. The web plates perpendicular to the chord direction are arranged every 100mm from the supporting plates, the thickness of the web plates is 2mm, the heights of the web plates are 45.628mm,34.221mm,22.814mm and 11.408mm from left to right, and the dimensional bodies are arranged at the positions 100mm from the tail ends of the flexible rear edges. The above is one of the examples. In practice the webs are typically 4-5 webs, preferably about 100mm apart, depending on the particular size of the trailing edge.

Supporting plate 1 and web 2 top and distributed driving device 6In connection with the airfoil surface covering the flexible skin 5, the distributed drive 6 drives the upper and lower flexible skins 5 to extend or compress in the chord direction to effect the upward or downward deflection of the trailing edge. In order to increase the torsional stiffness, a honeycomb-like torsional structure 4 is arranged between adjacent webs 2. The cellular torsion-resistant structure 4 is triangular in shape, 10 triangular cells are arranged along the chord direction, 6 triangular cells are arranged at each side of the web plate in the height direction, the side lengths of the triangular cells can be unequal, the structural form is shown in figure 2, the support plate, the web plate and the cellular torsion-resistant structure are made of 7075 aluminum alloy, the elastic modulus E =71.7GPa, the Poisson ratio mu =0.33, and the density rho =2.81g/cm ³ 。

Two structures with the same total amount of materials are compared, wherein one structure is a structure only provided with a shear core plate and a web plate, and the other structure is a structure arranged with a honeycomb-like grid, and the thickness of the honeycomb-like grid is 0.3mm. The two structures are simulated by ABAQUS, the simulation result is shown in a 3~4 graph, when the torsional rigidity is compared, the left end of the wing is fixedly supported, uniform forces with equal magnitude and opposite directions are applied to the upper end and the lower end of the supporting plate and the web plate according to the height proportion to form torque, when the maximum stress of the simulation result of the honeycomb-like structure is 1/2 of the allowable stress of the material, the same load is applied to the structure only provided with the shear core plate and the web plate, and the torsional rigidity of the honeycomb-like grid structure is far larger than that of the shear plate when the maximum displacement of the honeycomb-like structure is compared.

The above description is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, several modifications can be made without departing from the principle of the present invention, and these modifications should also be regarded as the protection scope of the present invention.

Claims

1. The structure for improving the torsional rigidity of the trailing edge structure of the flexible wing is characterized by comprising a wing non-deformation structure (7) and a trailing edge flexible structure (8), wherein the wing non-deformation structure (7) and the trailing edge flexible structure (8) are connected through a support plate (1);

the rear edge flexible structure (8) comprises a plurality of groups of webs (2) which are longitudinally arranged, distributed driving devices (6) are arranged at the top ends between every two adjacent webs (2), flexible skins (5) cover the outer sides of the distributed driving devices (6), and the distributed driving devices (6) drive the flexible skins (5) to extend or compress along the chord direction to realize upward or downward deflection of the rear edge flexible structure (8);

the supporting plates (1) and the web plates (2) and a plurality of groups of web plates (2) are connected in sequence through honeycomb-like anti-torsion structures (4), the honeycomb-like anti-torsion structures (4) are folded into triangular meshes by thin plates, and the folding line direction is parallel to the wingspan direction;

the flexible skin (5) is connected between the adjacent webs (2), the flexible skin (5) is supported by the webs (2), and the distributed driving device (6) is supported by the webs (2);

the device is characterized in that T-shaped flanges are arranged at the upper wing surface and the lower wing surface of the supporting plate (1), the front surfaces of the T-shaped flanges are connected with wing skins, the rear surfaces of the T-shaped flanges are connected with flexible skins, and under the driving of a distributed driving device (6), a rear edge flexible structure (8) changes the bending degree upwards or downwards; the triangular meshes in the honeycomb-like torsion-resistant structure (4) have equal or unequal triangular side lengths;

the web is provided with T-shaped edge strips at the upper and lower wing surfaces, the transverse edges of the T-shaped edge strips are connected with the flexible skin (5), and the vertical edges of the T-shaped edge strips are connected with the distributed driving device (6); the distributed driving device (6) adopts a fiber-reinforced sealed flexible cavity.

2. A structure for increasing the torsional stiffness of a trailing edge structure of a flexible wing according to claim 1, characterized in that the trailing edge flexible structure (8) further comprises an end-connected aft dimensional body (3).