A flexible skin skeleton that can be sheared and deformed

Abstract

This invention discloses a shear-deformable flexible skin, applicable to the field of flexible structure design for variator aircraft. It includes a deformable quadrilateral frame, a set of deformable flexible plates, and connecting rings. Connecting segments and bending segments are alternately distributed on the flexible plates. The bending segments are divided into upper and lower layers, bending outwards perpendicular to the plane of the flexible plate. The bending direction of the upper layer bending segment is opposite to that of the lower layer bending segment. The bending direction of the same layer of bending segments before and after the connecting segment is opposite to that of the connecting segment. Adjacent flexible plates have their adjacent bending segments slidably connected by connecting rings, forming a double-layer mesh structure. The left and right ends of the flexible plates are connected to the left and right edges of the quadrilateral frame. The crests of the bending segments of the flexible plates adjacent to the leading edge of the mesh structure are welded to the leading edge, and the crests of the bending segments of the flexible plates adjacent to the trailing edge are welded to the trailing edge, forming the flexible skin skeleton. The out-of-plane load-bearing capacity of this invention is provided by the vertical surface of the flexible plates, while the slidable bending segments of the flexible plates provide shear deformation capability.

Description

Technical Field

[0001] This invention belongs to the field of flexible structure design for variant aircraft, specifically relating to a flexible skin skeleton that can be sheared and deformed. Background Technology

[0002] Variant aircraft can autonomously change their shape during flight to adapt to changing mission environments, ensuring optimal aerodynamic efficiency throughout the entire flight process. Variable-camber wings increase lift and improve aerodynamic efficiency; variable-sweep wings meet the requirements of supersonic flight, subsonic cruise, and short takeoff and landing. Flexible skins must be used to ensure a smooth outer surface for variator aircraft.

[0003] Flexible skin structures need to ensure a smooth and continuous outer surface, provide sufficient in-plane deformation, and possess adequate out-of-plane stiffness to withstand aerodynamic loads. For unidirectional or bidirectional deformable flexible skins, researchers have proposed numerous solutions to meet these technical requirements through various approaches. However, for variable-sweep wing structures, changing the sweep angle typically involves shear deformation of the skin, resulting in fewer corresponding design solutions. The shear deformation capability of the flexible skin is a key technical challenge in variable-sweep wing skin structures and is crucial to their effectiveness. Summary of the Invention

[0004] This invention proposes a flexible skin skeleton to address the issues of in-plane shear deformation and out-of-plane load-bearing capacity in flexible skins. This flexible skin skeleton has a simple structure and high design flexibility. The flexible skin skeleton of this invention uses a grid structure formed by arranged flexible plates as support, and connecting rings enable sliding connections between adjacent flexible plates. This flexible skin skeleton can achieve in-plane shear deformation and has out-of-plane load-bearing capacity; its structure is simple and easy to manufacture.

[0005] This invention is implemented as follows:

[0006] A shear-deformable flexible skin skeleton includes a deformable quadrilateral frame, deformable flexible plates inside the deformable quadrilateral frame, and connecting rings. Connecting segments and bending segments are alternately distributed on the flexible plates. The bending segments are divided into upper and lower layers. The bending segments bend outwards perpendicular to the plane of the flexible plate, with the upper and lower bending segments bending in opposite directions. The bending directions of the same layer of bending segments before and after the connecting segments are opposite. Bending segments in the same layer that are close to each other between adjacent flexible plates are slidably connected by connecting rings, forming a double-layer mesh structure. The out-of-plane load-bearing capacity of the flexible skin skeleton is provided by the vertical surface of the flexible plates, while the slidable bending segments of the flexible plates provide shear deformation capacity.

[0007] When the wing sweep angle changes, the flexible skin skeleton structure is subjected to shear force. Due to the antisymmetry of shear force, relative sliding occurs between the curved sections at the connection of adjacent flexible plates. Due to the constraint of the connecting ring, the flexible plates form an integral structure, and relative sliding only occurs at the connection of the curved sections of adjacent flexible plates. At the same time, the flexible plates generate interaction forces in the normal direction at the connection of the connecting ring. The curved sections of the flexible plates undergo bending deformation under the action of force, which further enhances the shear deformation capability of the flexible skin skeleton.

[0008] Furthermore, the deformable quadrilateral frame includes a left frame, a right frame, a front edge, and a rear edge; the lengths of the front edge and the left and right frames remain constant, while the length of the rear edge is variable; the left and right frames are parallel and always maintain the direction of airflow, and the left frame, right frame, front edge, and rear edge form a deformable frame, and the angle between the front edge and the left and right frames can be changed.

[0009] Furthermore, the flexible plate is connected to the left and right sides of the deformable quadrilateral frame at both ends. The crest of the flexible plate bending section adjacent to the front edge of the grid structure is welded to the front edge, and the crest of the flexible plate bending section adjacent to the rear edge is welded to the rear edge, forming a flexible skin skeleton.

[0010] Furthermore, the front edge, left side frame, and right side frame are C-shaped profiles with openings facing the inside of the quadrilateral frame; the length of the front edge remains constant, and the outer side of the end of the front edge C-shaped profile is welded with connecting holes and connected to the ends of the left side frame and right side frame by rivets; the quadrilateral frame is a quadrilateral with parallel but unequal left and right sides, and the length of the rear edge is variable to ensure that the left and right sides remain parallel during the change of sweep angle.

[0011] Furthermore, the rear edge is composed of square hollow tubes, with several square hollow tubes nested in sequence, making the length of the rear edge of the frame variable; the upper and lower sides of the hollow tube at the rear edge end are welded with connecting holes and connected to the ends of the left and right frames by rivets; when the sweep angle changes, the angle between the front edge and the left and right frames changes, the left and right frames always remain parallel, the angle between the rear edge and the left and right frames changes, and the length of the rear edge changes at the same time, the movement of the frame causes the quadrilateral frame to change shape; pin holes (9) are provided at equal intervals on the two edge strips of the left and right frames, and the joint at the end of the flexible plate is placed on the C-profile. Inside the groove, the center of the joint is collinear with the center of the pin hole (9), and the flexible plate and the left and right frames are connected by the pin, so that the flexible plate can rotate around the pin. Connection points are set on the inner sides of the front and rear edges to fix the upper and lower curved sections of the flexible plate. Connection blocks are set at the corresponding positions in the C-shaped groove of the front edge to connect with the crest of the curved section of the flexible plate, for connecting the flexible plate. Ears are welded to the outer sides of the upper and lower edge strips of the front edge, and ears are welded to the outer sides of the square hollow tube at the rear edge. The ears at the front and rear edges are connected to the ends of the left and right frames by rivets to form a quadrilateral frame.

[0012] Furthermore, the left frame, right frame, front edge, and rear edge are connected by hinges to form a quadrilateral frame. Flexible plates are sequentially connected to the connection points on the left and right frames, so that the flexible plates are arranged laterally. The curved sections of the flexible plates adjacent to the front edge are welded to the front edge, and the curved sections of the flexible plates adjacent to the rear edge are welded to the rear edge. The maximum sweep-back state is treated with surface filling. First, rubber foam material is used for flexible filling inside the double-layer mesh structure, and then a layer of adhesive film is covered on the outer surface of the flexible skin support structure. When the sweep-back angle changes, the length of the front edge remains unchanged, only the corner is generated, the length of the left and right frames remains unchanged and always stays in the direction of airflow, and the shear deformation of the flexible skin skeleton is provided by the relative sliding of the curved sections of the flexible plates.

[0013] Furthermore, the flexible plate includes a set of alternating connecting segments and bending segments; the total length of the flexible plate is L, the height is h, the thickness is t, the length of the connecting segment is l, the bending segment is an arc with a chord length of a and an arch height of s, the distance between the flexible plate adjacent to the front edge and the front edge is s, the distance between the flexible plate adjacent to the rear edge and the rear edge is s, and the distance between adjacent flexible plates is 2s; a slit is cut in the middle of the bending segment, and the straight line of the slit divides the bending segment of the flexible plate into upper and lower layers, namely the upper bending segment and the lower bending segment; anti-crack holes are provided at the left and right ends of the slit;

[0014] The flexible board has connecting sections at both ends, which are bent into closed circular joints at the ends. The inner diameter of the circular joint is larger than the diameter of the connecting pins on the left and right sides. The height is the height of the side frame minus the thickness of the upper and lower edge strips, and it is used to connect with the left and right sides.

[0015] Furthermore, the connecting ring is a strip of metal material. The strip of metal material is wound around the junction of two adjacent flexible plate bending sections, and the outermost end is glued to form a connecting ring to connect the flexible plates. When the connecting ring is wound, a gap is reserved between it and the two adjacent flexible plate bending sections, so that the flexible plate bending sections can slide relative to each other at the connection.

[0016] Furthermore, the upper curved section of the flexible plate is connected to the upper curved section of the adjacent flexible plate through a connecting ring, and the lower curved section is connected to the lower curved section of the adjacent flexible plate through a connecting ring. A group of flexible plates are arranged side by side, and the curved sections of the adjacent flexible plates are staggered in the upper and lower layers to form a double-layer grid structure.

[0017] The advantages of this invention compared to the prior art are as follows:

[0018] 1. The flexible skin skeleton of the present invention achieves shear deformation through a sliding connection method, and at the same time has strong out-of-plane load-bearing capacity.

[0019] 2. The flexible skin skeleton of the present invention can adjust the geometric parameters of the flexible plate to adapt to different structural size requirements, and has good designability. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of a flexible skin skeleton that can be sheared and deformed according to the present invention;

[0021] Figure 2 This is a schematic diagram of a deformable quadrilateral frame in a flexible skin skeleton that can be sheared and deformed according to the present invention.

[0022] 2(a) is a schematic diagram of the deformable quadrilateral frame structure; 2(b) is a schematic diagram of the border connection method; 2(c) is a schematic diagram of the left and right border structure; 2(d) is a schematic diagram of the front edge structure.

[0023] Figure 3 This is a schematic diagram of the flexible plate structure in a flexible skin skeleton that can be sheared and deformed according to the present invention.

[0024] Figure 4 This is a schematic diagram of the flexible plate connection method in a flexible skin skeleton that can be sheared and deformed according to the present invention; wherein 4(a) is a schematic diagram of a double-layer mesh structure; 4(b) is a schematic diagram of a cross section at the connection of the flexible plates;

[0025] Figure 5 This is a schematic diagram of the connecting ring structure in a flexible skin skeleton that can be sheared and deformed according to the present invention;

[0026] Figure 6 This is a schematic diagram of the trailing edge structure of a flexible skin skeleton that can be sheared and deformed according to the present invention.

[0027] Figure 7 This is a diagram illustrating the relative motion at the connection points of the flexible plates in a shearable and deformable flexible skin skeleton according to the present invention.

[0028] Among them, 1-left frame, 2-right frame, 3-front edge, 4-rear edge, 5-flexible board, 6-connection point, 7-rivet, 8-joint, 9-pin hole, 10-connecting block, 11-upper layer connection point, 12-lower layer connection point, 13-upper layer bending section, 14-lower layer bending section, 15-connecting section, 16-bending section, 17-connecting ring. Detailed Implementation

[0029] To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the following examples provide a more detailed description of the invention. It should be noted that the specific embodiments described herein are merely illustrative and not intended to limit the scope of the invention.

[0030] The flexible skin skeleton that can be sheared and deformed proposed in this invention is as follows: Figures 1-2As shown, the flexible skin skeleton consists of a deformable quadrilateral frame, a set of deformable flexible plates 5, and connecting rings 17. The front edge 3 and the left and right side borders of the quadrilateral frame have constant lengths, while the rear edge 4 has a variable length. The left and right side borders are parallel and always maintain the direction of airflow. The four borders form a deformable frame, and the angle between the front edge 3 and the left and right side borders can be changed. Connecting sections 15 and bending sections 16 are alternately distributed on the flexible plates 5. The bending sections 16 are divided into upper and lower layers. The bending sections 16 bend outwards perpendicular to the plane of the flexible plate 5. The bending direction of the upper bending section 13 is opposite to that of the lower bending section 14. The bending direction of the same layer of bending sections 16 before and after the connecting sections is opposite. The bending sections 16 of the same layer that are close to each other between adjacent flexible plates 5 are slidably connected by connecting rings 17 to form a double-layer grid structure. The left and right ends of the flexible plates 5 are connected to the left and right side borders of the quadrilateral frame. The crests of the flexible plate bending sections adjacent to the front edge 3 are welded to the front edge 3, and the crests of the flexible plate bending sections adjacent to the rear edge are welded to the rear edge 4, forming the flexible skin skeleton. The out-of-plane load-bearing capacity of the flexible skin skeleton is provided by the vertical surface of the flexible plate 5, while the sliding flexible plate bending section provides shear deformation capacity.

[0031] (1) Schematic diagram of flexible plate 5 as shown in the figure Figure 3 As shown. The flexible plate 5 consists of a set of alternating curved sections 16 and connecting sections 15, with a total length of L, a height of h, and a plate thickness of t. The length of the connecting section 15 is l. The curved section 16 is an arc with a chord length of a and an arch height of s. The distance between the flexible plate adjacent to the front edge and the front edge 3 is s, and the distance between adjacent flexible plates 5 is 2s. A slit is cut in the middle of the curved section of the flexible plate, and the straight line of the slit divides the curved section of the flexible plate into upper and lower layers. Crack-stopping holes are provided at the left and right ends of the slit. The two ends of the flexible plate 5 are connecting sections 15, which are bent into closed circular joints at the ends. The inner diameter of the circular joint is larger than the diameter of the connecting pins on the left and right frames, and the height is the height of the frame minus the thickness of the upper and lower edge strips, used for connection with the left and right frames.

[0032] (2) Schematic diagram of deformable quadrilateral frame as shown in Figure Figure 2 As shown. The deformable quadrilateral frame consists of a front edge 3, a rear edge 4, and left and right side frames. The front edge 3 and the left and right side frames are C-shaped profiles with openings facing the inside of the quadrilateral frame. The left and right side frames are parallel and have a constant length, always maintaining the direction of airflow. The front edge 3 has a constant length, and a connecting block 10 is installed in the C-shaped groove. The outer end of the C-shaped profile has a lug with a connecting hole, which is connected to the end of the left and right side frames by rivets 7. The quadrilateral frame is a quadrilateral with two parallel but unequal sides. To ensure that the left and right side frames remain parallel during the change of sweep angle, the rear edge 4 must have a variable length. A schematic diagram of the rear edge 4 is shown below. Figure 6As shown. The rear edge 4 is composed of square hollow tubes, with several square hollow tubes nested sequentially, making the length of the rear edge 4 variable. Ears with connecting holes are welded to the upper and lower sides of the hollow tubes at the ends of the rear edge 4, and connected to the ends of the left and right frames via rivets 7. When the sweep angle changes, the angle between the front edge 3 and the left and right frames changes, while the left and right frames remain parallel. The angle between the rear edge 4 and the left and right frames changes, and the length of the rear edge 4 also changes. The movement of the frames causes the quadrilateral frame to change shape. Pin holes 9 are evenly spaced on the two edge strips of the left and right frames. The joint 8 at the end of the flexible plate 5 is placed in the groove of the C-shaped profile. The center of the joint 8 is collinear with the center of the pin hole 9. The flexible plate 5 is then connected to the left and right frames by pins, allowing the flexible plate 5 to rotate around the pins. The connecting block 10 of the front edge 3 and the inner side of the rear edge 4 are provided with upper connection points 11 and lower connection points 12 for fixed connection to the upper and lower curved sections of the flexible plate 5.

[0033] (3) Schematic diagram of connecting ring 17 as shown in the figure Figures 4-5 As shown. The connecting ring 17 is a strip of metal material. The strip of metal material is wound around the junction of the two adjacent flexible plate bending sections, and the outermost end is glued to form the connecting ring 17 to connect the flexible plates 5. When the connecting ring 17 is wound, a certain gap is reserved between it and the two bending sections 16 of the adjacent flexible plates 5, so that the bending sections of the flexible plates can slide relative to each other at the connection.

[0034] (4) A schematic diagram of the connection method of flexible plate 5 is shown below. Figure 4 As shown, the upper curved section 13 (solid line) of the flexible plate is connected to the upper curved section 13 (solid line) of the adjacent flexible plate through connecting ring 17, and the lower curved section 14 (dashed line) is connected to the lower curved section 14 (dashed line) of the adjacent flexible plate through connecting ring 17. A group of flexible plates 5 are arranged side by side, and the curved sections of adjacent flexible plates are staggered in the upper and lower layers to form a double-layer grid structure. The length and width of the grid structure can be adjusted according to the actual structural requirements to determine the length and number of flexible plates 5, the arch height of the curved section 16, and the length of the connecting section 15, so that the flexible skin skeleton has good designability. The vertical surface of each flexible plate 5 provides the out-of-plane load-bearing capacity of the flexible skin skeleton, the curved section of the flexible plate can generate bending deformation, providing in-plane expansion and contraction deformation capacity, and the sliding connection formed by the connecting ring 17 allows relative sliding between the flexible plates 5, providing the shear deformation capacity of the flexible skin skeleton.

[0035] (5) A schematic diagram of the relative motion at the connection of the flexible plate 5 when the flexible skin skeleton undergoes shear deformation is shown below. Figure 7As shown, when the wing sweep angle changes, the flexible skin skeleton structure is subjected to shear force. Due to the antisymmetry of shear force, relative sliding occurs between the curved sections 16 at the connection of adjacent flexible plates 5. Due to the constraint of the connecting ring 17, the flexible plates 5 form an integral structure, and relative sliding only occurs at the connection of the curved sections of adjacent flexible plates. Simultaneously, an interaction force is generated in the normal direction at the connection of the flexible plates 5 at the connecting ring 17, causing the curved sections of the flexible plates to bend under the force, further enhancing the shear deformation capability of the flexible skin skeleton.

[0036] (6) Schematic diagram of the flexible skin skeleton structure that can be sheared and deformed. Figure 1 As shown, the left and right frames, front edge 3, and rear edge 4 are connected by hinges to form a quadrilateral frame. Flexible plates 5 are sequentially connected to the connection points 6 on the left and right frames, so that the flexible plates 5 are arranged laterally. The curved sections of the flexible plates adjacent to the front edge 3 are welded to the front edge 3, and the curved sections of the flexible plates adjacent to the rear edge 4 are welded to the rear edge 4. Connecting rings 17 are installed at the junctions of the curved sections of adjacent flexible plates to form a slidable connection, thus forming a flexible skin skeleton that can be sheared and deformed. To ensure the smoothness of the outer surface of the flexible skin and considering the characteristics of rubber materials, surface filling treatment is performed for the maximum sweep-back state. First, rubber foam material is used for flexible filling inside the double-layer mesh structure, and then a layer of adhesive film is covered on the outer surface of the flexible skin support structure. When the sweep-back angle changes, the length of the front edge 3 remains unchanged, only the corner is generated, the length of the left and right frames remains unchanged and always stays in the direction of airflow, and the shear deformation of the flexible skin skeleton is provided by the relative sliding of the curved sections of the flexible plates.

[0037] The specific embodiments of the present invention will be further described in detail below using specific data.

[0038] In this embodiment, it is assumed that the left frame 1 of the flexible skin skeleton has a length of L1 = 300 mm, the right frame 2 has a length of L2 = 280 mm, and the front edge 3 has a length of L3 = 250 mm. A C-shaped profile is selected, with a cross-sectional height H = 10 mm, a cross-sectional width B = 10 mm, and a thickness t1 = 1 mm. The material is hard aluminum. The flexible plate 5 is made of 7-series aluminum alloy with an elastic modulus E = 71.7 GPa, Poisson's ratio μ = 0.33, and a density ρ = 2.81 g / cm³. 3 The connecting ring 17 is made of alloy material, with a width of 3mm, a thickness of 1mm, and a length of 36mm when straightened. The sweep angle of the leading edge 3 of the flexible skin skeleton ranges from 5.7° to 49°. With a sweep angle of 49° as the initial state, the initial length of the trailing edge 4 is 237mm; when the sweep angle of the leading edge 3 is 5.7°, the length of the trailing edge 4 is 250mm.

[0039] Drill 3mm diameter pin holes 9 on the left and right frame sides. Twenty pin holes 9 are set on the left frame 1, with the topmost pin hole 9 7.5mm from the top end and the bottommost pin hole 9 7.5mm from the bottom end, and the remaining pin holes 9 spaced 15mm apart. Similarly, twenty pin holes 9 are set on the right frame 2, with the topmost pin hole 9 7mm from the top end and the bottommost pin hole 9 7mm from the bottom end, and the remaining pin holes 9 spaced 14mm apart. Connecting holes are provided at the ends of the left and right frame sides for connecting the front edge 3 and the rear edge 4. The rear edge 4 consists of six square hollow tubes, each 44mm long and 1mm thick. Three of these are thick tubes with a cross-sectional side length of 12mm, and the remaining three are thin tubes with a cross-sectional side length of 10mm. The thick and thin tubes are arranged alternately and nested to form the rear edge 4. Connecting blocks 9 are set at the corresponding positions in the groove of the front edge 3C profile where it connects to the crest of the flexible plate bending section, for connecting the flexible plate 5. Ear pieces are welded to the outer sides of the upper and lower edge strips of the front edge 3, and ear pieces are welded to the outer sides of the square hollow tube at the end of the rear edge 4. The ear pieces at the ends of the front edge 3 and the rear edge 4 are connected to the ends of the left and right frame by rivets 7 to form a quadrilateral frame.

[0040] Twenty flexible panels 5 are selected, each with a total length of 310mm, a thickness of t=1mm, and a height of h=10mm. The connecting section 15 has a length of l=20mm. Six sets of curved sections 16 are set on the panel. A slit is cut at the centerline of the height of the curved section 16, dividing the panel into upper and lower layers. The starting point of the first slit is 20mm from the end, and the ending point of the last slit is also 20mm from the end. The slit length is 28.3mm, and the slit spacing is 20mm. Curved sections 15 with a chord length a=22mm and an arch height s=7.5mm are stamped out. The curved sections 16 bend outwards perpendicular to the plane of the flexible panel 5. The bending direction of the upper curved section 13 is opposite to that of the lower curved section 14, and the bending direction of the same layer of curved sections before and after the connecting section is opposite. Crack-stopping holes are provided at the ends of the slits, with a diameter three times that of the slit. The end of the flexible panel 5 is 8mm high. The end panel is rolled into a ring with an inner diameter of 3.4mm, forming a circular joint. The length of the flexible board 5 after processing is 252mm.

[0041] The joints 8 at the ends of the flexible plate 5 are placed in the C-shaped grooves of the left and right side frames. The center of the joint 8 is collinear with the center of the pin hole 9 in the side frame, and the flexible plate 5 is then connected to the left and right side frames by pins. The flexible plate 5 adjacent to the front edge 3 is welded to the connecting block 9 of the front edge 3, and the flexible plate 5 adjacent to the rear edge 4 is welded to the rear edge 4. The weld point is located at the crest of the curved section 16. Strip metal material is wound around the junction of the curved sections of two adjacent flexible plates to form a connecting ring 17. The upper curved section is connected to the upper curved section of the adjacent flexible plate, and the lower flexible plate is connected to the lower curved section of the adjacent flexible plate, forming a double-layer mesh structure. Since the flexible skin skeleton is a quadrilateral with unequal sides, the curved sections of the flexible plate will bend and deform during installation to change the length of the plate, thereby adapting to the structural dimensions. When the flexible skin skeleton undergoes shear deformation, slippage and bending deformation will occur between the curved sections of adjacent flexible plates, providing good deformation capacity for the flexible skin skeleton.

[0042] To ensure a smooth outer surface of the flexible skin, rubber foam is used for flexible filling inside the double-layer mesh structure, and a layer of adhesive film is applied to the outer surface. Taking a leading edge sweep angle of 49° as the initial state, filling the mesh structure with foam rubber and covering the outer surface of the skin with an adhesive film in this state ensures that the filler and covering are only subjected to tension during deformation, effectively avoiding the problem of bulging of the rubber material under pressure.

[0043] The parameters h, t, l, a, r, s and the length of the flexible plate 5 can be adjusted to change the geometric dimensions of the flexible plate 5, thereby changing the in-plane deformation capacity and out-of-plane load-bearing capacity of the flexible skin skeleton to meet actual structural requirements.

[0044] This flexible skin frame can achieve shear deformation and in-plane expansion and contraction deformation, while also having strong out-of-plane load-bearing capacity. The adjustable geometry ensures that the structure has good designability.

[0045] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements can be made without departing from the principle of the present invention, and these improvements should also be considered within the scope of protection of the present invention.

Claims

1. A flexible skin skeleton capable of shear deformation, characterized in that, The flexible skin skeleton includes a deformable quadrilateral frame, a deformable flexible plate (5) inside the deformable quadrilateral frame, and a connecting ring (17). The flexible plate (5) is alternately distributed with connecting sections (15) and bending sections (16). The bending sections are divided into upper and lower layers, namely upper bending section (13) and lower bending section (14). The bending sections bend outward perpendicular to the plane of the flexible plate. The bending directions of the upper bending section (13) and the lower bending section (14) are opposite. The bending directions of the same layer of bending sections before and after the connecting section are opposite. The bending sections of the same layer of adjacent flexible plates that are close to each other are slidably connected by connecting rings (17) to form a double-layer grid structure. The out-of-plane load-bearing capacity of the flexible skin skeleton is provided by the vertical surface of the flexible plate (5), and the slidable flexible plate bending section (16) provides shear deformation capacity. The flexible skin skeleton achieves shear deformation through a slidable connection method and has a strong out-of-plane load-bearing capacity. When the wing sweep angle changes, the flexible skin skeleton structure is subjected to shear force. Due to the antisymmetry of shear force, relative sliding occurs between the curved sections at the connection of adjacent flexible plates. Due to the constraint of the connecting ring (17), the flexible plates form an integral structure, and relative sliding only occurs at the connection of the curved sections of adjacent flexible plates. At the same time, the flexible plates will generate interaction forces in the normal direction at the connection of the connecting ring. The curved sections of the flexible plates will bend and deform under the action of force, which further enhances the shear deformation capability of the flexible skin skeleton. The deformable quadrilateral frame includes a left frame (1), a right frame (2), a front edge (3), and a rear edge (4); the lengths of the front edge (3), the left frame (1), and the right frame (2) remain constant, while the length of the rear edge (4) is variable; the left frame (1) and the right frame (2) are parallel and always maintain the direction of airflow, and the left frame (1), the right frame (2), the front edge (3), and the rear edge (4) form a deformable frame, and the angle between the front edge (3) and the left frame (1) and the right frame (2) can be changed.

2. The shear-deformable flexible skin skeleton according to claim 1, characterized in that, The flexible plate (5) is connected to the left side frame (1) and right side frame (2) of the deformable quadrilateral frame at both ends. The crest of the flexible plate bending section adjacent to the front edge of the grid structure is welded to the front edge (3), and the crest of the flexible plate bending section adjacent to the rear edge is welded to the rear edge (4) to form a flexible skin skeleton.

3. The shear-deformable flexible skin skeleton according to claim 2, characterized in that, The front edge (3), left frame (1), and right frame (2) are C-shaped profiles with openings facing the inside of the quadrilateral frame. The length of the front edge (3) remains constant. The outer side of the C-shaped front edge (3) is welded with connecting holes and connected to the ends of the left frame (1) and right frame (2) by rivets (7). The quadrilateral frame is a quadrilateral with parallel but unequal left and right frames. To ensure that the left and right frames remain parallel during the change of sweep angle, the length of the rear edge (4) is variable. The rear edge (4) is composed of square hollow tubes, and several square hollow tubes are nested in sequence to make the length of the rear edge of the frame variable. The upper and lower sides of the hollow tube at the end of the rear edge (4) are welded with connecting holes and connected to the ends of the left and right frames by rivets (7) to form a quadrilateral frame. When the sweep angle changes, the angle between the front edge and the left and right frames changes. The left and right frames remain parallel. The angle between the rear edge and the left and right frames changes, and the length of the rear edge changes.

4. The shear-deformable flexible skin skeleton according to claim 3, characterized in that, Pin holes (9) are provided at equal intervals on the two edge strips of the left and right sides. The joint (8) at the end of the flexible plate is placed in the groove of the C-shaped material. The center of the joint is collinear with the center of the pin hole (9). The flexible plate and the left and right sides are connected by pins so that the flexible plate can rotate around the pin. Upper connection point (11) and lower connection point (12) are provided on the inner side of the front and rear edges to fix the upper and lower curved sections of the flexible plate. Connecting blocks (10) are provided at the corresponding positions in the C-shaped groove of the front edge to connect with the crest of the curved section of the flexible plate for connecting the flexible plate.

5. The shearable and deformable flexible skin skeleton according to claim 2, characterized in that, The left frame (1), right frame (2), front edge (3), and rear edge (4) are connected by hinges to form a quadrilateral frame. The flexible plates are connected to the connection points on the left frame (1) and right frame (2) in sequence, so that the flexible plates are arranged in the horizontal direction. The curved section of the flexible plate adjacent to the front edge is welded to the front edge, and the curved section of the flexible plate adjacent to the rear edge is welded to the rear edge. The maximum sweep-back state is treated with surface filling. First, rubber foam material is used to flexibly fill the inside of the double-layer grid structure, and then a layer of adhesive film is covered on the outer surface of the flexible skin support structure. When the sweep-back angle changes, the leading edge length remains unchanged, only the corner is generated, the length of the left and right sides remains unchanged and always stays in the direction of airflow, and the shear deformation of the flexible skin skeleton is provided by the relative sliding of the flexible plate bending section.

6. The shear-deformable flexible skin skeleton according to claim 1, characterized in that, The flexible plate (5) includes a set of alternating connecting sections (15) and bending sections (16); the total length of the flexible plate (5) is L, the height is h, the plate thickness is t, the length of the connecting section is l, the bending section is an arc with a chord length of a and an arch height of s, the distance between the flexible plate adjacent to the front edge and the front edge (3) is s, the distance between the flexible plate adjacent to the rear edge and the rear edge (4) is s, and the distance between adjacent flexible plates is 2s; a slit is cut in the middle of the bending section (16), and the straight line of the slit divides the bending section of the flexible plate into upper and lower layers, namely the upper bending section (13) and the lower bending section (14); anti-crack holes are provided at the left and right ends of the slit; The flexible plate has connecting sections (15) at both ends, and is bent into closed circular joints at the ends. The inner diameter of the circular joint is larger than the diameter of the connecting pins on the left and right sides. The height is the height of the side frame minus the thickness of the upper and lower edge strips, and is used to connect with the left and right sides.

7. The shear-deformable flexible skin skeleton according to claim 1, characterized in that, The connecting ring (17) is a strip of metal material. The strip of metal material is wrapped around the junction of the two adjacent flexible plate bending sections, and the outermost end is glued to form a connecting ring to connect the flexible plates. When the connecting ring is wrapped, a gap is reserved between it and the two adjacent flexible plate bending sections so that the flexible plate bending sections can slide relative to each other at the connection.

8. The shear-deformable flexible skin skeleton according to claim 7, characterized in that, The upper curved section of the flexible plate is connected to the upper curved section of the adjacent flexible plate through a connecting ring (17), and the lower curved section is connected to the lower curved section of the adjacent flexible plate through a connecting ring. A group of flexible plates are arranged side by side, and the curved sections of the adjacent flexible plates are staggered in the upper and lower layers to form a double-layer grid structure.

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