Flexible spar for a curved variable-sweep wing

Abstract

The embodiment of the present application provides a main beam (3) of a curved variable sweep wing. The main beam (3) of the curved variable sweep wing is generated by combining a flexible leaf spring and a flexible hinge. According to the embodiment of the present application, on the basis of the leaf spring, a flexible cross hinge geometry feature is added, so that the main beam (3) has good large deformation stiffness decoupling performance keeping ability, and is suitable for the curved variable sweep wing.

Description

Technical Field

[0001] This invention relates to the field of aerospace technology, and more specifically, to a flexible main beam that can be used on a curved variable sweep wing. Background Technology

[0002] This section provides information to help in a better understanding of aspects of this disclosure. Therefore, the statements in this section should be read in this manner and should not be construed as an admission of what is in the prior art or what is not in the prior art.

[0003] To meet the complex and varied operating conditions that may be encountered during flight missions, designers began experimenting with installing curved, variable-sweep wings on the fuselage to achieve optimal aerodynamic configuration under different environmental conditions. Two main problems needed to be solved to achieve this were the design and manufacture of the variable-sweep frame and the design and installation of the wing skin.

[0004] Improving the design of the flexible main beam to meet the requirements of various wing sweep angle deformations while bearing flight aerodynamic loads is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] This summary is provided to illustrate a selection of concepts in a simplified form, which will be further described in the detailed description below. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to limit the scope of the claimed subject matter.

[0006] The purpose of this invention is to provide a flexible main beam for a curved variable sweep wing, so as to solve the problems of insufficient skeleton deformation capacity in the prior art.

[0007] An embodiment of the present invention provides a main sparsity for a curved variable sweep wing, which is formed by a combination of flexible leaf springs and flexible hinges.

[0008] According to an exemplary embodiment of the present invention, the flexible hinge comprises flexible hinge cells arranged end-to-end. A flexible leaf spring extends in the spanwise direction of the wing, serving as the central skeleton of the flexible hinge.

[0009] According to an exemplary embodiment of the present invention, the flexible hinge cell has an X-shaped structure.

[0010] According to an exemplary embodiment of the present invention, the main spars of the curved variable-sweep wing are arranged at a distance from the maximum thickness of the airfoil and are integrally connected to the wing ribs, wingtips, and wing roots. The X-shaped structure of the flexible hinged cell is arranged between the two ribs.

[0011] According to an exemplary embodiment of the present invention, the thickness of the main spars of the curved variable sweep wing is set according to the airfoil surface of the wing.

[0012] According to an exemplary embodiment of the present invention, the following advantages are available:

[0013] 1) Solve the stiffness decoupling problem of the flexible lattice variable swept wing main beam, and at the same time solve the problem of weakened stiffness decoupling performance under large deformation state of the leaf spring type main beam.

[0014] 2) The flexible cross-hinge configuration has good support stiffness retention under deformation conditions. Its basic configuration is approximately a pair of equal-length leaf springs arranged in a cross pattern. The flexible lattice variable-sweep wing main beam of this invention is based on leaf springs, with the addition of flexible cross-hinge geometric features to ensure that the structure has good stiffness decoupling performance retention under large deformation.

[0015] 3) By combining flexible cross hinges and flexible leaf springs, the main sparsity of the deformable wing can maintain good support stiffness within its own deformation capacity in the drag direction. Furthermore, this configuration exhibits excellent stiffness decoupling performance, meeting the wing's lift-direction load-bearing capacity while allowing the main sparsity to achieve a maximum sweepback angle of 94°. The sweepback deformation capacity provided by this main sparsity surpasses that of most traditional swept-back deformable wings. Attached Figure Description

[0016] This disclosure, its preferred mode of use, and further objectives are best understood when read in conjunction with the accompanying drawings by referring to the following detailed description of embodiments.

[0017] To more clearly illustrate the technical solutions of the specific embodiments of the present invention, the accompanying drawings used in the description of the specific embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without any creative effort.

[0018] Figure 1 This is a schematic diagram of the stress on the main spars of a flexible swept-back deformable wing using flexible leaf springs.

[0019] Figure 2 This is a schematic diagram of a flexible cross-hinge cell;

[0020] Figure 3 This is a schematic diagram of the basic configuration of a flexible reinforced cross-hinge cell.

[0021] Figure 4 This is a schematic diagram of a flexible main beam generated by linearly arranging flexible reinforced cross-hinge cells;

[0022] Figure 5 This is a three-dimensional view of a flexible lattice variable swept wing bone structure.

[0023] Figure 6This is a top view of a flexible lattice variable swept wing bone structure.

[0024] 1-Leaf spring main beam; 2-Hinge cell; 3-Strengthened main beam Detailed Implementation

[0025] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0027] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0028] Figure 1 This is a schematic diagram of the bending structure of the main beam of the flexible swept-back deformable wing under stress using a flexible leaf spring (1). Figure 1 In this context, xyz represents the coordinate system.

[0029] In the conceptual design of flexible lattice variable-sweep wings, the wing main spars need to be designed as a single unit while achieving stiffness decoupling in the lift and drag directions. Flexible leaf springs are a typical flexible mechanism component capable of achieving this stiffness decoupling requirement. Designers can adjust the cross-sectional characteristics of the leaf spring to create significant differences in bending stiffness along its thickness and width. However, flexible leaf springs can only guarantee stiffness decoupling under small structural deformation conditions. As structural deformation increases, the stiffness decoupling performance of the leaf spring weakens significantly, potentially leading to structural instability in the torsional direction. This directly limits its application in engineering projects requiring large deformation.

[0030] Figure 2 This is a schematic diagram of a flexible cross-hinge cell.

[0031] The flexible cross-hinge cell (2) has an X-shaped structure and is positioned between the wing ribs. The basic configuration of the flexible cross-hinge can also be modified into a C-type or DC-type to address flexible mechanism issues such as improving hinge axis drift performance. However, in terms of mechanical performance, the X-type configuration has the best stiffness decoupling performance among flexible cross-hinge configurations without added leaf spring reinforcement, and the flexible main beam designed based on this configuration best meets the design requirements.

[0032] Figure 3 This is a schematic diagram of the basic configuration of a flexible reinforced cross-hinge cell.

[0033] like Figure 3 As shown, the flexible cross-hinge cell (2) can be reinforced at the center by arranging leaf spring elements to obtain the basic flexible reinforced cross-hinge cell configuration. Here, the thickness direction is defined as the support direction, and the structural stiffness in this direction is the support stiffness. Compared with the flexible cross-hinge, the support stiffness of the cell structure after leaf spring reinforcement is greatly improved. Its internal geometric characteristic parameters are: P cell envelope size; S strut thickness; H cell thickness. In practical applications, these parameters will be coupled with the aeroelastic analysis of the wing and continuously adjusted and iterated. The equivalent stiffness in the support direction of the entire wing and the power consumption of the drive deformation are used as the basis for the final parameter selection. Different characteristic size parameters correspond to different flight conditions.

[0034] Figure 4 This is a schematic diagram of a flexible main beam generated by linearly arranging flexible reinforced cross-hinge cells.

[0035] The basic configuration of the flexible main beam is shown in Figure (4). It is mainly obtained by arranging flexible reinforced cross hinge cells end to end and linearly arraying cell groups. The basic configuration of the flexible reinforced cross hinge cell is shown in Figure (3). It is composed of flexible leaf springs and flexible cross hinges ( Figure 2 The combined structure possesses both the stiffness decoupling properties of a flexible leaf spring and the necessary torsional stiffness provided by the flexible cross hinges to prevent structural instability in the torsional direction. Figure 1 Linear arrays amplify flexible mechanisms in series, enhancing their deformation capabilities while retaining the properties of basic cells, thereby achieving the design objective of maintaining the supporting stiffness of the wing main sparsity under large deflection deformation.

[0036] Figure 5 This is a three-dimensional view of a flexible lattice variable swept wing bone structure.

[0037] Figure 6 This is a top view of a flexible lattice variable swept wing bone structure.

[0038] The flexible main beam serves as a model of a flexible lattice variable swept wing. Figure 5 , Figure 6 The key aerodynamic load-bearing components of the wing are mainly located at the point of maximum airfoil thickness, ensuring sufficient design margin in the load-bearing direction for material supply. They are integrated with the wing ribs, wingtips, and wing roots to achieve a closed force transmission path for the wing structure. The flexible main sparsity is not constant in thickness, representing a compromise made to ensure the main load-bearing structure conforms to the airfoil surface. During the sweep-back deformation of the flexible wing, the flexible main sparsity also participates in the deformation, primarily driven by the wing's own drive mechanism.

[0039] According to embodiments of the present invention, the following advantages are available:

[0040] 1) Solve the stiffness decoupling problem of the flexible lattice variable swept wing main beam, and at the same time solve the problem of weakened stiffness decoupling performance under large deformation state of the leaf spring type main beam.

[0041] 2) The flexible cross-hinge configuration has good support stiffness retention under deformation conditions. Its basic configuration is approximately a pair of equal-length leaf springs arranged in a cross pattern. The flexible lattice variable-sweep wing main beam designed in this work is based on leaf springs, with the addition of flexible cross-hinge geometric features to ensure that the structure has good stiffness decoupling performance retention under large deformation.

[0042] 3) By combining flexible cross hinges and flexible leaf springs, the main sparsity of the deformable wing can maintain good support stiffness within its own deformation capacity in the drag direction. Furthermore, this configuration exhibits excellent stiffness decoupling performance, meeting the wing's lift-direction load-bearing capacity while allowing the main sparsity to achieve a maximum sweepback angle of 94°. The sweepback deformation capacity provided by this main sparsity surpasses that of most traditional swept-back deformable wings.

[0043] This invention can be applied to deformable wing aircraft with flexible concepts, such as biomimetic aircraft, and can also be used as a flexible hinge with large deflection in the design of flexible mechanisms.

[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A main beam (3) of a curved variable-sweep wing, generated by a combination of a flexible plate spring and a flexible hinge; wherein said flexible plate spring extends in a spanwise direction of the wing as a central skeleton of said flexible hinge; wherein said flexible hinge comprises flexible cross-hinge cells (2) arranged in a head-to-tail manner; wherein said flexible cross-hinge cells (2) are of an X-shaped structure; wherein said X-shaped structure of said flexible cross-hinge cells (2) is arranged between two wing ribs; wherein said flexible cross-hinge cells (2) are reinforced by arranging said flexible plate spring in the center; wherein said main beam (3) of the curved variable-sweep wing is arranged at a location of maximum thickness of the airfoil and is integrally connected with the wing ribs, the wing tip, and the wing root of the wing; wherein the thickness of said main beam (3) of the curved variable-sweep wing is set in accordance with the profile of the airfoil of the wing.

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