Superstructure with asymmetric rigidity and wing variable-camber framework

Abstract

The invention provides a superstructure with asymmetric rigidity and a wing variable camber framework, the superstructure comprises two symmetrically arranged first unit cells and a plurality of second unit cells arranged between the two first unit cells in an end-to-end sequential linear butt joint mode, the first unit cells and the second unit cells as well as the adjacent second unit cells are connected through the flexible hinge structures, and the flexible hinge structures are arranged on the side walls of the first unit cells and the second unit cells, so that the superstructure can be telescopically deformed, the problem of cyclic load fatigue faced by a traditional flexible beam variable-camber framework is solved, and the flexibility of the flexible beam variable-camber framework is improved. Meanwhile, the cavity in the flexible hinge structure can generate asymmetric rigidity during deformation, compared with a traditional flexible structure with symmetric rigidity, the superstructure can be accurately guided to be bent and deformed in the expected deformation direction, deformation of the superstructure in the unexpected direction at the balance position before deformation is avoided, and when the superstructure serves as a wing variable-camber framework, the deformation of the superstructure in the unexpected direction is avoided. And the lift augmentation effect of the wing can be prevented from being influenced by unexpected deformation.

Description

Technical Field

[0001] The present invention belongs to the technical field of mechanical superstructures and additive manufacturing, and particularly relates to a superstructure with asymmetric stiffness and a variable-camber wing skeleton. Background Art

[0002] A morphing aircraft is one that can flexibly change its wing shape during flight based on the flight environment and mission requirements, achieving overall performance that meets these requirements. This capability can be achieved through a variety of methods, including variable span, chord, thickness, sweep, and camber. Currently, variable camber wing technology primarily utilizes a flexible skin and a deformable skeleton to achieve this camber function. The flexible skin primarily bears the aerodynamic pressure and wing torsional shear forces, while the deformable skeleton primarily bears the bending moment and supports the skin's contour.

[0003] There are two types of traditional deformable skeleton designs: the first is based on the deflection deformation of a flexible beam skeleton structure. However, this type of skeleton is subject to high cyclic stress for a long time, making it prone to fatigue damage and subsequent fracture. Furthermore, the deflection deformation does not have directional heterogeneity, and is prone to deflection in undesired directions, affecting the lift-enhancing effect of the variable-camber wing. The second is based on the mechanical movement of a complex linkage structure. In actual use, this structure involves issues such as assembly, lubrication, and motion maintenance. The complex linkage system relies on the connection of kinematic hinges. Traditional hinges are either rigid or flexible. Traditional rigid hinges require consideration of machining accuracy, fitting tolerances, operating lubrication, and maintenance. Traditional flexible hinges, due to their relatively soft texture, have difficulty maintaining motion around a single, defined axis, which may lead to motion deviations. Furthermore, complex linkage mechanisms generally have multiple control systems, making lightweighting difficult. Summary of the Invention

[0004] The purpose of the present invention is to solve the above-mentioned technical problems existing in the existing deformable skeleton, and to provide a superstructure with asymmetric stiffness and a wing variable curvature skeleton.

[0005] To achieve the above objectives, the technical solutions provided by the present invention are:

[0006] A superstructure with asymmetric stiffness, comprising two symmetrically arranged first unit cells and a plurality of second unit cells, wherein the second unit cells are arranged between the two first unit cells in an end-to-end linear docking manner, and the first unit cells and the second unit cells are collinear in an undeformed state;

[0007] The first unit cell and the second unit cell, as well as adjacent second unit cells, are connected by a flexible hinge structure, and the side walls of the first unit cell and the second unit cell are both provided with a flexible hinge structure, so that the superstructure can bend and deform and expand and contract along its length direction;

[0008] The middle portion of the side wall of the second unit cell in the width direction is inclined inward at a set angle;

[0009] The flexible hinge structure has a cavity extending therethrough, the cavity opening being perpendicular to the plane in which the first unit cell and the second unit cell are located; the cross-sectional profile of the cavity includes a waveform and an isosceles triangle continuously connected to the waveform, the top of the isosceles triangle being adjacent to one edge of the flexible hinge structure, and the crest of the waveform being adjacent to the other symmetrical edge of the flexible hinge structure; and the height of the isosceles triangle being smaller than the wave height of the waveform;

[0010] The first unit cell, the second unit cell and the flexible hinge structure constitute a one-dimensional basic unit chain.

[0011] Furthermore, the cross-sectional size of the cavity of the flexible hinge structure is obtained by adjusting the parameters according to the target bending stiffness requirement.

[0012] Furthermore, the waveform includes a symmetrically arranged rising segment and falling segment, and a crest portion connecting the rising segment and the falling segment; the two endpoints of the base of the isosceles triangle coincide with the endpoints of the rising segment and the falling segment respectively.

[0013] Furthermore, the first unit cell is a U-shaped frame structure, comprising a first right-angle L-shaped plate and a second right-angle L-shaped plate that are symmetrically arranged;

[0014] One end portion of the first right-angle L-shaped plate and the second right-angle L-shaped plate are connected to each other via a first flexible hinge structure;

[0015] The other ends of the first right-angle L-shaped plate and the second right-angle L-shaped plate are both provided with the first flexible hinge structure for connecting with the corresponding position of the second unit cell;

[0016] The first right-angle L-shaped plate and the second right-angle L-shaped plate are both rigid parts.

[0017] Furthermore, the second unit cell includes a first T-shaped structure, a second T-shaped structure, a third T-shaped structure, and a fourth T-shaped structure, wherein the first T-shaped structure and the second T-shaped structure are arranged on the same side and connected in parallel by a second flexible hinge structure; the butt end of the first T-shaped structure and the butt end of the second T-shaped structure are aligned in a plane before deformation, and the two butt ends and the second flexible hinge structure arranged therebetween together form a continuous inwardly inclined slope;

[0018] The third T-shaped structure and the fourth T-shaped structure are arranged symmetrically with the first T-shaped structure and the second T-shaped structure respectively;

[0019] The third T-shaped structure and the fourth T-shaped structure are arranged on the same side and connected in parallel by the second flexible hinge structure; the butt end of the third T-shaped structure and the butt end of the fourth T-shaped structure are aligned in a plane before deformation, and the two butt ends and the second flexible hinge structure arranged therebetween form a continuous inwardly inclined slope;

[0020] The first T-shaped structure and the third T-shaped structure, and the second T-shaped structure and the fourth T-shaped structure, which are symmetrically arranged, are all connected via the first flexible hinge structure;

[0021] The first T-shaped structure, the second T-shaped structure, the third T-shaped structure and the fourth T-shaped structure are all rigid parts.

[0022] Furthermore, the superstructure is formed by an FDM dual-nozzle integrated method, so that the first unit cell and the second unit cell can interlock with each other layer by layer at the boundaries of the corresponding flexible hinge structure;

[0023] The first unit cell and the second unit cell are formed of PLA material, and the flexible hinge structure is formed of TPU material.

[0024] Furthermore, in the superstructure, a triangular connecting rod structure is used to replace the T-shaped structure in the second unit cell.

[0025] The present invention also provides a two-dimensional planar superstructure, comprising a plurality of the one-dimensional basic unit chains; the one-dimensional basic unit chains are arranged in a parallel array on a plane, and adjacent one-dimensional basic unit chains share a sidewall structure.

[0026] The present invention also provides a wing variable camber frame, comprising a plurality of sliding support assemblies and the above-mentioned one-dimensional basic unit chain; the wing variable camber frame is horizontally installed in the inner cavity of the airfoil skin, and the length direction of the wing variable camber frame is along the chord direction of the airfoil; the upper and lower inner walls of the airfoil skin are respectively provided with a first motion slide groove and a second motion slide groove arranged along the chord direction of the airfoil; the plurality of sliding support assemblies are respectively arranged at the installation position of the flexible hinge structure near the central axis of the second unit cell in the length direction;

[0027] The sliding support assembly has clamping parts on both sides, respectively used to clamp the side walls on both sides in the width direction of the second unit cell, and the top and bottom of the sliding support assembly have sliding support parts extending upward and downward, respectively matching the first motion slide groove and the second motion slide groove, and can slide back and forth along the first motion slide groove and the second motion slide groove;

[0028] Moreover, one side of the isosceles triangle of the flexible hinge structure located in the middle of the first unit cell faces the inner side of the first unit cell, and one side of the isosceles triangle of the flexible hinge structure located at both ends of the first unit cell faces the outer side of the first unit cell; one side of the isosceles triangle of the two flexible hinge structures located in the middle of the length direction of the second unit cell faces the outer side of the second unit cell, and one side of the isosceles triangle of the two flexible hinge structures located in the middle of the width direction of the second unit cell faces the inner side of the second unit cell.

[0029] Furthermore, the sliding support assembly includes a sleeve support and a sleeve rod support; the sleeve support includes a first rectangular frame, an upper sleeve fixedly connected to the top of the first rectangular frame, and a lower sleeve fixedly connected to the bottom of the first rectangular frame; the upper sleeve and the lower sleeve are both L-shaped structures, and the ends of the horizontal sections are respectively smoothly fixedly connected to the top center and the bottom center of the first rectangular frame; the ends of the vertical sections can respectively match the first motion groove and the second motion groove on the airfoil skin, and can slide back and forth along the first motion groove and the second motion groove; the vertical section of the upper sleeve is equal in length to the vertical section of the lower sleeve;

[0030] The sleeve rod support member includes a second rectangular frame, an upper sleeve rod fixedly connected to the top of the second rectangular frame, and a lower sleeve rod fixedly connected to the bottom of the second rectangular frame; the upper sleeve rod and the lower sleeve rod are both L-shaped, and the ends of the horizontal sections are smoothly fixedly connected to the top center and the bottom center of the second rectangular frame respectively, the vertical section of the upper sleeve rod and the vertical section of the lower sleeve rod are matched and sleeved in the upper sleeve and the lower sleeve respectively, and can rotate around the axis in the upper sleeve and the lower sleeve respectively.

[0031] The advantages of the present invention are:

[0032] 1. The superstructure with asymmetric stiffness designed in the present invention includes two symmetrically arranged first unit cells, and a plurality of second unit cells arranged between the two first unit cells in an end-to-end linear docking manner. The first unit cell and the second unit cell, as well as the adjacent second unit cells, are connected by a flexible hinge structure, and the side walls of the first unit cell and the second unit cell are provided with a flexible hinge structure, so that the superstructure can bend and deform and expand and contract along its length direction, solving the cyclic load fatigue problem faced by traditional flexible beam variable curvature skeletons. At the same time, the cavity designed in the flexible hinge structure can generate asymmetric stiffness during the bending process of the structure. Compared with the traditional flexible structure with symmetrical stiffness, it can accurately guide the superstructure to bend and deform in the desired deformation direction, avoiding the superstructure from deforming in an undesirable direction at the equilibrium position before deformation. When used as a wing variable curvature skeleton, it can avoid the undesirable deformation affecting the lift effect of the wing.

[0033] 2. The present invention designs a superstructure with asymmetric stiffness. The flexible hinge structure and the adjacent first and second cells are made of additive manufacturing, specifically the FDM double-nozzle integration method. The first and second cells are formed of PLA material, and the flexible hinge structure is formed of TPU material. The first and second cells can interlock with each other layer by layer at the boundaries of the corresponding flexible hinge structure, so that the first and second cells as rigid parts are firmly connected to the flexible hinge structure. By designing the rigid-flexible interlocking depth, the flexible hinge structure is constrained to rotate around the fixed axis to the greatest extent, ensuring the accuracy of the superstructure bending angle. The fully flexible hinge structure has no backlash, no friction, no gap, no noise, and no wear during use, which solves the problems of assembly, lubrication, motion maintenance, etc. involved in the bending skeleton of the traditional complex connecting rod structure during actual use.

[0034] 3. The cavity cross-section designed in the flexible hinge structure designed in the present invention includes a waveform and an isosceles triangle connected to the waveform. The height of the isosceles triangle is less than the wave height of the waveform. The design of the cavity enables the flexible hinge structure to generate asymmetric stiffness. By designing and adjusting the cavity cross-section parameters, different stiffness requirements can be achieved to meet different bending requirements, and the design is strong.

[0035] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments with reference to the accompanying drawings, in which:

[0037] Figure 1 is a schematic structural diagram of the first unit cell in the superstructure with asymmetric stiffness of the present invention;

[0038] Figure 2 is a schematic structural diagram of the second unit cell in the superstructure with asymmetric stiffness of the present invention;

[0039] Figure 3 is a schematic diagram of a flexible hinge structure in a superstructure with asymmetric stiffness according to the present invention;

[0040] Figure 4 yes Figure 3 Schematic diagram of the cross-sectional profile of the cavity in the flexible hinge structure;

[0041] Figure 5 Schematic diagram of the positive torque deformation of the flexible hinge structure in the present invention;

[0042] Figure 6 Schematic diagram of the reverse torque deformation of the flexible hinge structure in the present invention;

[0043] Figure 7 Schematic diagram of the stiffness change of the flexible hinge structure at different torsion angles in the present invention;

[0044] Figure 8 Schematic diagram of the ABA-type superstructure before and after deformation in an embodiment of the present invention;

[0045] Figure 9 1 is a schematic diagram of the structure of the ABA-type superstructure after topology optimization in an embodiment of the present invention;

[0046] Figure 10 is a schematic diagram of a two-dimensional planar superstructure according to an embodiment of the present invention;

[0047] Figure 11 It is a schematic structural diagram of a wing variable camber skeleton based on the superstructure of the present invention;

[0048] Figure 12 It is a schematic structural diagram of a wing variable camber skeleton based on the topologically optimized superstructure of the present invention;

[0049] Figure 13 This is a schematic diagram of the assembly of a wing variable camber frame and an airfoil skin based on the superstructure of the present invention;

[0050] Figure 14 It is a schematic structural diagram of the sliding support assembly in the variable camber frame of the wing of the present invention;

[0051] Figure 15 It is a cross-sectional view of the sliding support assembly in the wing variable camber skeleton of the present invention.

[0052] Explanation of the figure marks: 1-first unit cell, 101-first right-angle L-shaped plate, 102-second right-angle L-shaped plate, 2-second unit cell, 201-first T-shaped structure, 202-second T-shaped structure, 203-third T-shaped structure, 204-fourth T-shaped structure, 3-flexible hinge structure, 301-waveform, 302-isosceles triangle, 4-sliding support assembly, 401-sleeve support, 402-sleeve rod support, 5-wing skin. DETAILED DESCRIPTION

[0053] The following describes in detail embodiments of the present invention. The embodiments are exemplary and intended to explain the present invention, but are not to be construed as limiting the present invention.

[0054] An embodiment of the present invention provides a superstructure with asymmetric stiffness, comprising two symmetrically arranged first unit cells 1 and a plurality of second unit cells 2. The second unit cells 2 are arranged end-to-end linearly between the two first unit cells, and in their undeformed state, the first unit cells 1 and the second unit cells 2 are collinear. The superstructure also comprises a plurality of flexible hinge structures 3, with the flexible hinge structures 3 connecting the first unit cells and the second unit cells, as well as adjacent second unit cells, so that the superstructure can bend and deform and expand and contract along its length. The middle portion of the side wall of the second unit cell located in the width direction is tilted inward at a set angle, so that the flexible hinge structure 3 located in the middle portion of the side wall forms a certain angle with the vertical direction, so that when the rigid bodies on both sides of the flexible hinge structure on the side wall rotate about the axis, they can bend and deform relative to the plane of the first unit cell before deformation. That is, the first unit cell 1 bends and contracts only within its own plane, while the second unit cell 2 can bend and twist relative to the plane of the first unit cell. The first unit cell, the flexible hinge structure, and the second unit cell are connected to form a one-dimensional basic unit chain.

[0055] The flexible hinge structure 3 includes a cavity extending through the structure, perpendicular to the plane of the first and second unit cells. The cross-sectional profile of the cavity includes a waveform and an isosceles triangle continuously connected to the waveform, with the height of the isosceles triangle being less than the wave height of the waveform. The cross-sectional dimensions of the flexible hinge structure's cavity can be adjusted based on the desired bending stiffness. Specifically, the waveform includes symmetrically arranged ascending and descending segments, as well as a crest connecting the ascending and descending segments. The two endpoints of the base of the isosceles triangle coincide with the endpoints of the ascending and descending segments, respectively.

[0056] The superstructure is formed using the FDM dual-nozzle integrated method, so that the first unit cell and the second unit cell can interlock with each other layer by layer at the boundaries of the corresponding flexible hinge structure; among them, the first unit cell 1 and the second unit cell 2 are formed using PLA material, and the flexible hinge structure 3 is formed using TPU material.

[0057] Reference Figure 1 The first unit cell has a U-shaped frame structure, comprising a first right-angled L-shaped panel 101 and a second right-angled L-shaped panel 102, arranged symmetrically. One end of each of the first and second right-angled L-shaped panels is connected to each other via a first flexible hinge structure; the other ends of each of the first and second right-angled L-shaped panels are each provided with a first flexible hinge structure for connecting to a corresponding position in the second unit cell. Both the first and second right-angled L-shaped panels are rigid components.

[0058] Reference Figure 2The second unit cell includes a first T-shaped structure 201, a second T-shaped structure 202, a third T-shaped structure 203, and a fourth T-shaped structure 204. The first T-shaped structure 201 and the second T-shaped structure 202 are arranged on the same side and connected in parallel by a second flexible hinge structure. Before deformation, the butt joint of the first T-shaped structure and the butt joint of the second T-shaped structure are aligned in a planar configuration. The two butt joints, together with the second flexible hinge structure disposed therebetween, form a continuous inwardly inclined surface.

[0059] The third T-shaped structure 203 and the fourth T-shaped structure 204 are arranged symmetrically with the first T-shaped structure and the second T-shaped structure, respectively. The third and fourth T-shaped structures are arranged on the same side and connected in parallel by a second flexible hinge structure. Before deformation, the butt joint end of the third T-shaped structure and the butt joint end of the fourth T-shaped structure are aligned in a planar configuration, and the two butt joint ends, together with the second flexible hinge structure disposed therebetween, form a continuous inwardly inclined surface.

[0060] The first and third T-shaped structures, and the second and fourth T-shaped structures, which are symmetrically arranged, are all connected by a first flexible hinge structure. The first T-shaped structure 201, the second T-shaped structure 202, the third T-shaped structure 203, and the fourth T-shaped structure 304 are all rigid parts.

[0061] Reference Figure 3 and Figure 4 , a schematic diagram of the flexible hinge structure. The height and thickness of the flexible hinge structure are equal to those of the upper plate of the unit cell, respectively. A cavity extends through the flexible hinge structure 3 in the middle of the flexible hinge structure, near one edge. The cavity is perpendicular to the plane of the first and second unit cells. The cross-sectional profile of the cavity includes a waveform 301 and an isosceles triangle 302 connected to the waveform. The isosceles triangle is located near one edge of the flexible hinge structure, and the peak of the waveform is located near the other symmetrical edge of the flexible hinge structure. The height of the isosceles triangle is less than the height of the waveform. The peak of waveform 301 primarily enables the flexible hinge structure to twist around its central axis, while the top of the isosceles triangle provides less resistance to torsion in the forward direction and greater resistance in the reverse direction. These two components interact to create asymmetric stiffness in different locations of the flexible hinge structure in different torsion directions. This results in lower stiffness in the desired deformation direction, making it more susceptible to deformation, while increasing stiffness in the undesired deformation direction, making it less susceptible to deformation. Asymmetric stiffness can guide the structure to bend and deform in the desired deformation direction, preventing the structure from mistakenly entering an undesired deformation direction near the equilibrium position before deformation, resulting in a weakening of the lift-enhancing effect or even generating additional resistance.

[0062] The structural parameters of the cavity can be determined by adjusting the parameters of the cavity according to the target bending stiffness requirements. In this embodiment, the cavity structural parameters obtained by adjusting the parameters are as follows: the distance a from the peak of the waveform to the top of the isosceles triangle is 7.5mm, the radius of the fillet of the rising and falling sections of the waveform and the connection with the isosceles triangle is r=5mm, and the short semi-axis length 2b=7.5mm of the ellipse where the peak is located. The base length of the isosceles triangle is l=20mm and the height t=0.5mm. The torsion direction of the flexible hinge structure in normal working state is defined as positive, refer to Figure 5 When the flexible hinge structure is twisted forward, it is subjected to positive torque. When the twisting angle is small, the isosceles triangle side in the cavity begins to be under pressure, which can provide a small amount of support force. As the rotation angle increases, the isosceles triangle vertex position is extremely thin, which will induce the isosceles triangle to become unstable in the direction away from the geometric center of the flexible hinge structure, causing the stiffness to further decrease. Figure 7 As shown in the figure, when the torsion angle is about 5°, the isosceles triangle side of the flexible hinge structure becomes unstable, and the stiffness is greatly reduced. As the torsion angle continues to increase after the instability point, the isosceles triangle side of the flexible hinge structure can no longer provide support, that is, the resistance is extremely small, so the stiffness continues to remain at a low level. When the flexible hinge structure is subjected to reverse torque, the triangle side of the flexible body cavity is subjected to tension, which can provide considerable tension. Figure 6 ; And because the TPU material maintains a certain elasticity, it can provide a stable tensile force within the elastic limit, that is, a great resistance, which prevents the flexible hinge structure from twisting in the opposite direction. When the load disappears, the flexible hinge structure quickly returns to its initial equilibrium position. Therefore, the flexible hinge structure designed in this embodiment is more prone to positive torsional deformation (refer to Figure 5 ) and is not prone to reverse torsional deformation (refer to Figure 6 ), we call the flexible hinge structure designed in the present invention has directional anisotropy of bending stiffness.

[0063] In the present invention, a flexible hinge structure 3 is provided at the deformation node of the superstructure composed of the first and second unit cells. Because the flexible hinge has directional anisotropy of bending stiffness and a sharp transition in stiffness within a ±5° range, aligning the flexible hinge structure's easily bendable side (the wavy side) with the desired deformation direction of the superstructure effectively guides deformation. By placing the flexible hinge structure at the corresponding deformation node of the unit cell and aligning its easily bendable side (the wavy side) with the desired deformation direction, the superstructure exhibits a smaller restoring force in the desired deformation direction; conversely, it exhibits a larger restoring force in the undesired deformation direction, thereby preventing erroneous deformation of the superstructure.

[0064] Reference Figure 8This embodiment provides an ABA-type superstructure composed of a first unit cell and a second unit cell. It can be seen from the shapes of the ABA-type superstructure before and after deformation that the superstructure has a unique degree of freedom. By driving the angle between two rigid links of any deformation node in the superstructure, the bending deformation control of the entire superstructure can be achieved. There is no need to introduce multiple control devices, which simplifies the overall superstructure bending control process.

[0065] Reference Figure 9 Since the deformation of the superstructure mainly depends on the position of the deformation node and the direction of the rotation axis of the node, the rigid links between the nodes mainly play the role of angle geometry transmission and deformation mechanics transmission. Therefore, optimizing the geometry of the rigid links helps to reduce the stress concentration problem when the structure deforms. In order to enhance the anti-deformation ability and stability of the structure, this implementation Figure 8 The ABA-type superstructure is topologically optimized. After topology optimization, the T-type connecting rod in the second unit cell is optimized to a triangular connecting rod, and fillets are designed in areas prone to stress concentration. Figure 9 The dotted and solid lines represent the configurations before and after topology optimization, respectively.

[0066] Furthermore, in order to realize the bending of a large-scale planar structure according to actual bending requirements, this embodiment also provides a two-dimensional planar superstructure, such as Figure 10 As shown, the two-dimensional planar superstructure includes multiple one-dimensional basic unit chains mentioned above; the multiple one-dimensional basic unit chains are arranged in a parallel array on the plane, and adjacent one-dimensional basic unit chains share a sidewall structure.

[0067] Reference Figure 11-13 The present invention also provides a wing variable camber skeleton, comprising a plurality of sliding support assemblies 4 and the above-mentioned superstructure with asymmetric stiffness (one-dimensional basic unit chain). The number of second unit cell 2 arrays in the superstructure is determined according to the total length of the wing variable camber skeleton designed as needed. The wing variable camber skeleton is horizontally installed in the inner cavity of the airfoil skin 5, and the length direction of the wing variable camber skeleton is along the chord direction of the airfoil; the upper and lower inner walls of the airfoil skin are respectively provided with a first motion slide and a second motion slide arranged along the chord direction of the airfoil. The plurality of sliding support assemblies 4 are respectively arranged at the installation position of the flexible hinge structure (i.e., the second flexible hinge structure) near the center axis of the second unit cell in the length direction. The sliding support assemblies have clamping sleeves on both sides, which are respectively mounted on the side walls on both sides of the second unit cell in the width direction; and the sliding support assemblies 4 have a first support portion extending upward and matching the first motion slide at the top and a second support portion extending downward and matching the second motion slide at the bottom. The first support portion and the second support portion can slide back and forth along the first motion slide and the second motion slide, respectively, to achieve bending and extension of the wing variable camber skeleton along the chord direction of the airfoil.

[0068] Furthermore, to allow the wing's variable-camber frame to contract as a whole, the isosceles triangle of the flexible hinge structure located in the middle of the first unit cell faces inward, while the isosceles triangles of the flexible hinge structures located at both ends of the first unit cell face outward. The isosceles triangles of the two flexible hinge structures located in the middle of the second unit cell in the length direction face outward, while the isosceles triangles of the two flexible hinge structures located in the middle of the second unit cell in the width direction face inward.

[0069] Reference Figure 12 An embodiment of the present invention also provides another wing variable curvature skeleton, wherein the second unit cell in the wing variable curvature skeleton adopts a topologically optimized structure, and the rectangular frames on both sides of the sliding support assembly 4 are respectively inserted into the corresponding triangular connecting rod structures of the second unit cell.

[0070] Reference Figure 14-15 Specifically, a single sliding support assembly 4 includes a sleeve support 401 and a sleeve rod support 402. The sleeve support 401 includes a first rectangular frame, an upper sleeve connected to the top of the first rectangular frame, and a lower sleeve connected to the bottom of the first rectangular frame. The upper sleeve and the lower sleeve are both L-shaped structures, and the ends of the horizontal sections are smoothly and fixedly connected to the top center and the bottom center of the first rectangular frame respectively. The ends of the vertical sections can match the first and second motion grooves on the airfoil skin respectively, and can slide back and forth along the first and second motion grooves. The vertical section of the upper sleeve is equal to the vertical section of the lower sleeve. The sleeve rod support 402 includes a second rectangular frame, an upper sleeve rod connected to the top of the second rectangular frame, and a lower sleeve rod connected to the bottom of the second rectangular frame. The upper sleeve rod and the lower sleeve rod are both L-shaped structures, and the ends of the horizontal sections are smoothly and fixedly connected to the top center and the bottom center of the second rectangular frame respectively. The vertical section of the upper sleeve rod and the vertical section of the lower sleeve rod are matched and sleeved in the upper sleeve and the lower sleeve respectively, and can rotate around the axis in the upper sleeve and the lower sleeve respectively. The length of the vertical section of the upper sleeve rod and the lower sleeve rod is not greater than the length of the vertical section of the upper sleeve and the lower sleeve. When the wing's variable curvature skeleton begins to deform, the rectangular frame constrains the sliding support assembly and the side walls of the skeleton, causing the skeleton to shrink synchronously along the chord direction of the airfoil under the sliding action of the sliding support assembly, and the sleeves and sleeve rods that cooperate with each other at the upper and lower ends rotate coaxially. At the same time, since the upper and lower sleeves have equal dimensions in the direction perpendicular to the skeleton, when the sliding support assembly reciprocates in the motion groove of the airfoil skin, the distance between the airfoil skin at the upper and lower support positions and the skeleton remains unchanged, thereby promoting the airfoil skin to undergo bending movement adapted to the wing's variable curvature skeleton.

[0071] The above description is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with this technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed in the present invention, and these modifications or replacements should all be included in the scope of protection of the present invention.

Claims

1. A superstructure with asymmetric stiffness, characterized in that The invention comprises two symmetrically arranged first unit cells and a plurality of second unit cells, wherein the second unit cells are arranged between the two first unit cells in an end-to-end linear docking manner, and the first unit cells and the second unit cells are collinear in an undeformed state; The first unit cell and the second unit cell, as well as adjacent second unit cells, are connected by a flexible hinge structure, and the side walls of the first unit cell and the second unit cell are both provided with a flexible hinge structure, so that the superstructure can bend and deform and expand and contract along its length direction; The middle portion of the side wall of the second unit cell in the width direction is inclined inward at a set angle; The flexible hinge structure has a cavity extending therethrough, the cavity opening being perpendicular to the plane in which the first unit cell and the second unit cell are located; the cross-sectional profile of the cavity includes a waveform and an isosceles triangle continuously connected to the waveform, the top of the isosceles triangle being adjacent to one edge of the flexible hinge structure, and the crest of the waveform being adjacent to the other symmetrical edge of the flexible hinge structure; and the height of the isosceles triangle being smaller than the wave height of the waveform; The first unit cell, the second unit cell and the flexible hinge structure constitute a one-dimensional basic unit chain.

2. The superstructure with asymmetric stiffness according to claim 1, characterized in that: The cross-sectional size of the cavity of the flexible hinge structure is obtained by adjusting the variable parameters according to the target bending stiffness requirement.

3. The superstructure with asymmetric stiffness according to claim 2, characterized in that: The waveform includes a symmetrically arranged rising segment and a falling segment, and a crest portion connecting the rising segment and the falling segment; the two endpoints of the base of the isosceles triangle coincide with the endpoints of the rising segment and the falling segment respectively.

4. The superstructure with asymmetric stiffness according to claim 3, characterized in that: The first unit cell is a U-shaped frame structure, comprising a first right-angle L-shaped plate and a second right-angle L-shaped plate that are symmetrically arranged; One end portion of the first right-angle L-shaped plate and the second right-angle L-shaped plate are connected to each other via a first flexible hinge structure; The other ends of the first right-angle L-shaped plate and the second right-angle L-shaped plate are both provided with the first flexible hinge structure for connecting with the corresponding position of the second unit cell; The first right-angle L-shaped plate and the second right-angle L-shaped plate are both rigid parts.

5. The superstructure with asymmetric stiffness according to claim 4, characterized in that: The second unit cell includes a first T-shaped structure, a second T-shaped structure, a third T-shaped structure, and a fourth T-shaped structure. The first T-shaped structure and the second T-shaped structure are arranged on the same side and connected in parallel by a second flexible hinge structure. Before deformation, the butt end of the first T-shaped structure and the butt end of the second T-shaped structure are aligned in a plane, and the two butt ends and the second flexible hinge structure arranged therebetween form a continuous inwardly inclined slope. The third T-shaped structure and the fourth T-shaped structure are arranged symmetrically with the first T-shaped structure and the second T-shaped structure respectively; The third T-shaped structure and the fourth T-shaped structure are arranged on the same side and are connected in parallel via the second flexible hinge structure; The butt joint end of the third T-shaped structure and the butt joint end of the fourth T-shaped structure are aligned in a plane before deformation, and the two butt joint ends and the second flexible hinge structure disposed therebetween together form a continuous inwardly inclined slope; The first T-shaped structure and the third T-shaped structure, and the second T-shaped structure and the fourth T-shaped structure, which are symmetrically arranged, are all connected via the first flexible hinge structure; The first T-shaped structure, the second T-shaped structure, the third T-shaped structure and the fourth T-shaped structure are all rigid parts.

6. The superstructure with asymmetric stiffness according to any one of claims 1 to 5, characterized in that: The superstructure is formed by an FDM dual-nozzle integrated method, so that the first unit cell and the second unit cell can interlock with each other layer by layer at the boundaries of the corresponding flexible hinge structure; The first unit cell and the second unit cell are formed of PLA material, and the flexible hinge structure is formed of TPU material.

7. The superstructure with asymmetric stiffness according to claim 6, characterized in that: In the superstructure, a triangular connecting rod structure is used to replace the T-shaped structure in the second unit cell.

8. A two-dimensional planar superstructure, characterized in that It comprises a plurality of one-dimensional basic unit chains; the one-dimensional basic unit chains are arranged in a parallel array on a plane, and adjacent one-dimensional basic unit chains share a sidewall structure.

9. A wing variable camber frame, characterized in that: comprising a plurality of sliding support assemblies and a superstructure with asymmetric stiffness according to any one of claims 1 to 5; The wing variable camber frame is horizontally installed in the inner cavity of the airfoil skin, and the length direction of the wing variable camber frame is along the chord direction of the airfoil; the upper and lower inner walls of the airfoil skin are respectively provided with a first motion slide groove and a second motion slide groove arranged along the chord direction of the airfoil; a plurality of the sliding support assemblies are respectively arranged at the flexible hinge structure installation position near the central axis of the second unit cell in the length direction; The sliding support assembly has clamping parts on both sides, respectively used to clamp the side walls on both sides in the width direction of the second unit cell, and the top and bottom of the sliding support assembly have sliding support parts extending upward and downward, respectively matching the first motion slide groove and the second motion slide groove, and can slide back and forth along the first motion slide groove and the second motion slide groove; Moreover, one side of the isosceles triangle of the flexible hinge structure located in the middle of the first unit cell faces the inner side of the first unit cell, and one side of the isosceles triangle of the flexible hinge structure located at both ends of the first unit cell faces the outer side of the first unit cell; one side of the isosceles triangle of the two flexible hinge structures located in the middle of the length direction of the second unit cell faces the outer side of the second unit cell, and one side of the isosceles triangle of the two flexible hinge structures located in the middle of the width direction of the second unit cell faces the inner side of the second unit cell.

10. The wing variable camber skeleton according to claim 9, characterized in that: The sliding support assembly includes a sleeve support and a sleeve rod support; the sleeve support includes a first rectangular frame, an upper sleeve fixedly connected to the top of the first rectangular frame, and a lower sleeve fixedly connected to the bottom of the first rectangular frame; the upper sleeve and the lower sleeve are both L-shaped structures, and the ends of the horizontal sections are respectively smoothly fixedly connected to the top center and the bottom center of the first rectangular frame; the ends of the vertical sections can respectively match the first motion slide groove and the second motion slide groove on the wing skin, and can slide back and forth along the first motion slide groove and the second motion; the vertical section of the upper sleeve is equal to the vertical section of the lower sleeve; The sleeve rod support member includes a second rectangular frame, an upper sleeve rod fixedly connected to the top of the second rectangular frame, and a lower sleeve rod fixedly connected to the bottom of the second rectangular frame; the upper sleeve rod and the lower sleeve rod are both L-shaped, and the ends of the horizontal sections are smoothly fixedly connected to the top center and the bottom center of the second rectangular frame respectively, the vertical section of the upper sleeve rod and the vertical section of the lower sleeve rod are matched and sleeved in the upper sleeve and the lower sleeve respectively, and can rotate around the axis in the upper sleeve and the lower sleeve respectively.

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