A wing truss structure imitating a willow leaf

Abstract

The present invention provides a wing truss structure imitating a willow leaf. The main vein truss and the branch vein truss are used to replace the main vein and the branch vein of the willow leaf of a plant, thereby improving the bending resistance of the structure and making the structure not easily damaged when undergoing large bending deformation; the mesophyll skin is used to replace the mesophyll of the willow leaf of a plant, thereby enabling the mesophyll skin and the side plate to form a box structure and improving the torsional resistance of the structure; the adjacent main vein trusses are connected by branch vein trusses, further improving the torsional resistance of the structure while reducing the weight of the structure.

Description

Technical Field

[0001] The present invention belongs to the field of bionic structure design, and particularly relates to a wing truss structure imitating a willow leaf. Background Art

[0002] With the emergence of "Blue Whale" variant drones, "Pigeon" bionic drones, etc., drones are increasingly widely used in military and civilian fields, and mainly develop in three directions, namely bionic drones, variant drones, and multi-functional and multi-purpose drones.

[0003] The research on bionic drones is one of the most popular drone research fields at home and abroad. However, most of the existing bionic technologies start from the aerodynamic shape, hoping to optimize the aerodynamic layout of the drone by simulating the shape of organisms, especially birds, to improve the aerodynamic performance of the drone. In fact, in addition to flying organisms with high aerodynamic efficiency, there are also a large number of animal bones and plant structures with excellent structural performance in nature. People can still rely on these excellent natural animals and plants to bionic topological structures to improve the structural performance of the drone and reduce the structural weight of the drone.

[0004] For the wing truss structure currently adopted by small drones, there are the following problems: 1 Most designers focus on the bending resistance of the structure, so the existing wing truss structure has relatively weak torsional resistance; 2 Since the load received by the drone wing changes along the wingspan, but the existing wing truss structure has large bending deformation, traditional designers generally take a large safety factor to ensure that the wing structure is not damaged, which will cause the existing wing truss structure to be relatively heavy.

[0005] Chinese invention patent CN110576963B authorizes "a wing structure of a solar drone", which includes a frame bottom plate, a frame clamping plate, wing ribs, a storage battery, a solar panel, and an upper pressing frame. Among them, the bottom of the frame clamping plate is connected to the frame floor, and the top is fitted and installed with the wing rib. The upper surface of the wing rib is provided with a truss slot and an upper and lower beam slot, the rear wall socket is located at the bottom of the wing rib, and a wing leading edge support boss is provided at the leading edge of the wing rib. A plurality of wing ribs are composed of upper and lower wing ribs, truss bars, and rear walls. When manufacturing the skeleton, the shape of the wing is constrained by the frame and the upper pressing frame, and then the solar panel is bonded, and the storage battery is installed inside the wing. The advantage of this invention patent is that it makes full use of the wing space to install the storage battery and increases the structural stiffness of the wing through reasonable frame matching. However, the frame structure will inevitably increase the weight of the wing structure, especially unable to handle the large bending moment and torque at the wing root.

[0006] The Chinese invention patent CN113173243B authorizes "a piezoelectric fishbone wing structure", which includes multiple wing segments fixedly connected together, an active rib assembly, a driven rib assembly, a cable drive mechanism, a piezoelectric drive mechanism, and a skin structure inside the wing segment; the active rib assembly includes a front rib plate, a connecting plate, and an active rear rib plate. The front rib plate and the active rear rib plate are respectively vertically fixed to the fishbone rear rib on the lower end surface of the connecting plate; the fishbone rear rib includes a driven rear rib plate and a plurality of spokes connected to the driven rear rib plate; the tail end of the active rear rib plate is connected to the tail end of the driven rear rib plate through a connecting rod; the cable drive mechanism includes a drive servo, a servo traction rope, and a cable; the piezoelectric drive mechanism includes two piezoelectric films respectively arranged on the upper and lower surfaces of the active rear rib plate. The main advantage of this invention is that the wing can deform freely like a fishbone and can effectively resist the bending of the wing tip. However, its disadvantage is that each wing segment contains a large number of components, which greatly increases the weight of the wing. Summary of the Invention

[0007] In order to solve the technical problems of the existing wing truss structure with a large weight and weak torsional resistance, the present invention proposes a willow leaf-like lightweight structure.

[0008] The technical solution of the present invention is: a willow leaf-like wing truss structure, including a main vein truss 1, branch vein trusses 2, a mesophyll skin 3, and side plates 4;

[0009] There are two side plates 4, and the two side plates 4 are placed parallel to each other;

[0010] There are two main vein trusses 1, which are arranged parallel to each other on the upper and lower surfaces of the two side plates 4; the main vein truss 1 includes a square frame and several carbon fiber composite material rods parallel to each other inside the frame. Among them, the square frame and the carbon fiber composite material rods are all in the same plane, and the carbon fiber composite material rods are located inside the square frame, and the carbon fiber composite material rods and the side plates 4 are kept parallel to each other;

[0011] The branch vein trusses 2 are short inclined rods, and several branch vein trusses 2 are respectively arranged in the main vein trusses 1 on the upper and lower layers; after arrangement, the adjacent carbon fiber composite material rods are separated by the branch vein trusses 2 into regions with equal space sizes;

[0012] The several branch vein trusses 2 are divided into several groups. The branch vein trusses 2 between adjacent carbon fiber composite material rods are one group, and the inclination directions of adjacent groups of branch vein trusses 2 are opposite, and several groups of branch vein trusses 2 are all in the same plane; the branch vein trusses 2 in the same group are parallel to each other;

[0013] The mesophyll skin 3 wraps and winds the overall structure composed of the main vein truss 1, the branch vein trusses 2, and the side plates 4.

[0014] Furthermore, the width of the carbon fiber composite rods in the main vein truss is between 1.5 mm and 2 mm; the spacing between adjacent carbon fiber composite rods is between 6 mm and 8 mm; the square frame and the internal carbon fiber composite rods have the same thickness, both between 3 mm and 5 mm.

[0015] Furthermore, the included angle between the short diagonal rods and the carbon fiber composite rods in the branch vein truss 2 is 30° to 60°.

[0016] Furthermore, the width of the branch vein truss is between 1.2 mm and 1.7 mm, and the distance between adjacent branch vein trusses is between 15 mm and 22 mm; the thickness of the branch vein truss is the same as that of the main vein truss, between 3 mm and 5 mm.

[0017] Furthermore, the main vein truss 1 is made of a composite material with a stiffness greater than or equal to 91 GPa and a tensile strength greater than or equal to 3500 MPa.

[0018] Furthermore, the branch vein truss 2 is made of a composite material with a stiffness greater than or equal to 91 GPa and a tensile strength greater than or equal to 3500 MPa.

[0019] Furthermore, the mesophyll skin 3 is made of a flexible skin material.

[0020] Furthermore, after the mesophyll skin 3 wraps the overall structure, the whole becomes a box shape, improving the torsional resistance.

[0021] Furthermore, the mesophyll skin 3 is made to be in close contact with the main vein truss 1, the branch vein truss 2, the side plates 4 and the mesophyll skin 3 through a heater, and it is necessary to ensure that there is no air flow out between the main vein truss 1 and the branch vein truss 2, and between the main vein truss 1 and the side plates 4; and it is necessary to ensure that the mesophyll skin 3 between the main vein truss 1 and the branch vein truss 2, between the main vein truss 1 and the side plates 4, and between different branch vein trusses 2 is tightened.

[0022] Furthermore, the main vein truss 1 and the two side plates 4 are adhered together with glue.

[0023] Advantages of the Invention

[0024] The technical effect of the present invention is as follows: The present invention is mainly designed and made by imitating the structure of a willow leaf. It uses high-stiffness and high-strength composite materials to replace the main and secondary veins in the willow leaf, so that it has good bending resistance; it uses a flexible skin material to replace the mesophyll in the willow leaf, which can improve its torsional resistance; the design of connecting the main vein and the branch vein by imitating the willow leaf can improve the bending and torsional resistance of the UAV wing while reducing the structural weight.

[0025] Specifically:

[0026] 1. The present invention uses a main vein truss and branch vein trusses to replace the main vein and branch veins of a willow leaf plant. The main vein truss and branch vein trusses are respectively made of high - stiffness and high - strength composite materials, making the structure have strong bending resistance; at the same time, it also enables the structure to produce bending deformation like a willow leaf plant without damage.

[0027] 2. The present invention uses a flexible skin material as the mesophyll skin to replace the mesophyll in a willow leaf; the mesophyll skin between the main vein truss and the branch vein trusses, and between the main vein truss and the side plates is tightened to form a box - type structure with the side plates of the structure, improving the torsional resistance of the structure.

[0028] 3. The adjacent main vein trusses are connected by branch vein trusses; in this way, the torsional force borne by the structure is converted into tensile force, and further improves the torsional resistance of the structure on the premise of reducing the structure weight.

[0029] In summary, compared with the existing unmanned aerial vehicle (UAV) wing truss structure, the wing truss structure imitating a willow leaf of the present invention adopts the design of a main vein truss and branch vein trusses, which can further improve the bending resistance of the structure; compared with the existing UAV wing truss structure, the wing truss structure imitating a willow leaf of the present invention forms a box - type structure with the mesophyll skin, side plates, main vein truss and branch vein trusses to improve the bending resistance of the structure; compared with the existing UAV wing truss structure, the adjacent carbon fiber composite rods of the main vein truss of the wing truss structure imitating a willow leaf of the present invention are connected by branch vein trusses, so it can reduce the weight of the structure and has great advantages; if this structure is applied to the wing part of a small UAV, it can further reduce the structural weight of the small UAV, increase the range and flight time of the small UAV, and has great economic benefits. Brief Description of the Drawings

[0030] Figure 1 is the axonometric view of the wing truss structure imitating a willow leaf of the present invention;

[0031] Figure 2 is the front view of the wing truss structure imitating a willow leaf of the present invention;

[0032] Figure 3 is the top view of the wing truss structure imitating a willow leaf of the present invention;

[0033] Figure 4 is the side view of the wing truss structure imitating a willow leaf of the present invention;

[0034] Figure 5 is the front view of the application of the wing truss structure imitating a willow leaf of the present invention in the wing of a small UAV;

[0035] 1 - Main vein truss; 2 - Branch vein truss; 3 - Mesophyll skin; 4 - Side plate; 5 - UAV wing skin; Detailed implementation mode

[0036] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present invention.

[0037] The following further describes the embodiments of the present invention in detail with reference to the drawings:

[0038] See Figures 1-5 , an embodiment of the present invention is a wing truss structure imitating a willow leaf, which uses a main vein truss and a branch vein truss to replace the main vein and branch vein of a plant willow leaf, thereby improving the bending resistance of the structure and making the structure not easily damaged when undergoing large bending deformation; uses a mesophyll skin to replace the mesophyll of a plant willow leaf, thereby making the mesophyll skin and the side plate form a box structure to improve the torsional resistance of the structure; uses a branch vein truss to connect between adjacent main vein trusses, and further improves the torsional resistance of the structure while reducing the weight of the structure.

[0039] Specifically, this structure includes a main vein truss, a branch vein truss, a mesophyll skin and a side plate.

[0040] The main vein truss 1 is made of a composite material with a stiffness greater than or equal to 91 GPa and a tensile strength greater than or equal to 3500 MPa. In the embodiment of the present invention, a carbon fiber composite material with a stiffness equal to 91 GPa Young's modulus and a tensile strength equal to 3500 MPa Young's modulus is used; there are two main vein trusses 1, which are arranged in parallel on the upper and lower layers of the two side plates 4; the main vein truss 1 is adhered to the side plate 4 by special aviation glue; the main vein truss 1 includes a square frame and several carbon fiber composite material rods parallel to each other inside the frame, where the square frame and the carbon fiber composite material rods are all located in the same plane, and the carbon fiber composite material rods are located inside the square frame, and the carbon fiber composite material rods and the side plate 4 are kept parallel to each other; the adjacent carbon fiber composite material rods in the main vein truss 1 are connected by a branch vein truss 2; the width of the square frame is between 65 mm and 100 mm; the length of the square frame is between 350 mm and 520 mm.

[0041] The width of the carbon fiber composite rods in the main vein truss 1 is between 1.5 mm and 2 mm. In the example of the present invention, the width of the carbon fiber composite rods is 1.5 mm; the interval between adjacent carbon fiber composite rods is between 6 mm and 8 mm. In the example of the present invention, the interval between adjacent carbon fiber composite rods is 6 mm; the thickness of the square frame and the internal carbon fiber composite rods is the same, both between 3 mm and 5 mm. In the example of the present invention, the thickness of the square frame and the internal carbon fiber composite rods is 3 mm; the width of the square frame is between 65 mm and 100 mm. In the example of the present invention, the width of the square frame is 69 mm; the length of the square frame is between 350 mm and 520 mm. In the example of the present invention, the length of the square frame is 360 mm.

[0042] The branch vein truss 2 is made of a composite material with a stiffness greater than or equal to 91 GPa and a tensile strength greater than or equal to 3500 MPa. In the example of the present invention, a carbon fiber composite material with a Young's modulus of 91 GPa and a tensile strength of 3500 MPa is used; the branch vein truss 2 is a short inclined rod, and several branch vein trusses 2 are respectively arranged between adjacent carbon fiber composite rods in the upper and lower layers of the main vein truss 1; after arrangement, the space between adjacent carbon fiber composite rods is divided into regions with equal space sizes by the branch vein truss 2; the branch vein truss 2 and the main vein truss 1 are integrally formed, mainly obtained by cutting with an aviation laser cutter; the several branch vein trusses 2 are divided into several groups, and the branch vein trusses 2 between adjacent carbon fiber composite rods are one group. The inclination directions of adjacent groups of branch vein trusses 2 are opposite, and several groups of branch vein trusses 2 are all in the same plane; the branch vein trusses 2 in the same group are parallel to each other;

[0043] The width of the branch vein truss 2 is between 1.2 mm and 1.7 mm. In the example of the present invention, the width of the branch vein truss is 1.2 mm; the distance between adjacent branch vein trusses 2 is between 15 mm and 22 mm. In the example of the present invention, the distance between the branch vein trusses is 15 mm; the thickness of the branch vein truss 2 is the same as the thickness of the main vein truss 1, both between 3 mm and 5 mm. In the example of the present invention, the thickness of the branch vein truss is 3 mm; the included angle between the short inclined rod in the branch vein truss 2 and the carbon fiber composite rod in the main vein truss 1 is between 30° and 60°. In the example of the present invention, the included angle between the short inclined rod in the branch vein truss and the carbon fiber composite rod in the main vein truss is 60°

[0044] The main vein truss and the branch vein truss are integrally formed, mainly obtained by cutting the blank part with an aviation laser cutter.

[0045] The mesophyll skin 3 wraps around the overall structure composed of the main vein truss 1, the branch vein trusses 2, and the side plates 4; the mesophyll skin 3 is made of a flexible skin material. In the example of the present invention, the mesophyll skin is made of a heat-shrinkable film flexible skin material; the mesophyll skin 3 is brought into close contact with the main vein truss 1, the branch vein trusses 2, the side plates 4, and the mesophyll skin 3 itself through a heater, and it is necessary to ensure that there is no air flow out between the main vein truss 1 and the branch vein trusses 2, and between the main vein truss 1 and the side plates 4; and it is necessary to ensure that the mesophyll skin 3 between the main vein truss 1 and the branch vein trusses 2, between the main vein truss 1 and the side plates 4, and between different branch vein trusses 2 is tightened; after the mesophyll skin 3 wraps the overall structure, the whole becomes a box shape, improving the torsional resistance performance.

[0046] The side plates 4 are made of the same material as the main vein truss 1, which is a high-rigidity composite material with a Young's modulus of greater than or equal to 91 GPa. In the example of the present invention, carbon fiber composite material with a Young's modulus equal to 91 GPa is used; the side plates 4 have the same length as the main vein truss 1, which is between 350 mm and 520 mm. In the example of the present invention, it is 360 mm; the width of the side plates 4 is between 15 mm and 20 mm. In the example of the present invention, it is 16 mm; the thickness of the side plates 4 is between 3 mm and 5 mm. In the example of the present invention, it is 3 mm.

[0047] The skin 5 of the unmanned aerial vehicle wing is connected to a wing truss structure imitating a willow leaf of the present invention through an aviation special glue, so that the wing truss structure imitating a willow leaf of the present invention is applied to the wing of a small unmanned aerial vehicle; the wing truss structure imitating a willow leaf of the present invention is suitable for the wing structure of a small unmanned aerial vehicle with an aspect ratio greater than 5:1.

[0048] In summary, compared with the existing wing truss structures, the present invention has improvements in terms of structural weight, bending resistance performance, torsional resistance performance, etc. If it is applied to the field of small unmanned aerial vehicle wings, it can further reduce the structural weight of the unmanned aerial vehicle, improve the flight range, flight time, etc. of the unmanned aerial vehicle, and has great economic application prospects.

Claims

1. A wing truss structure imitating a willow leaf, characterized in that It includes a main vein truss (1), branch vein trusses (2), a mesophyll skin (3), and side plates (4); There are two of the side plates (4), and the two side plates (4) are placed parallel to each other; There are two of the main vein trusses (1), which are arranged parallel to each other on the upper and lower layers of the two side plates (4); the main vein truss (1) includes a square frame and several carbon fiber composite rods parallel to each other inside the frame. The square frame and the carbon fiber composite rods are all in the same plane, and the carbon fiber composite rods are inside the square frame, and the carbon fiber composite rods and the side plates (4) are kept parallel to each other; The branch vein trusses (2) are short inclined rods, and several branch vein trusses (2) are respectively arranged in the main vein trusses (1) of the upper and lower layers; after arrangement, the adjacent carbon fiber composite rods are separated by the branch vein trusses (2) into regions with equal space sizes; The several branch vein trusses (2) are divided into several groups. The branch vein trusses (2) between adjacent carbon fiber composite rods are one group. The inclination directions of adjacent groups of branch vein trusses (2) are opposite, and several groups of branch vein trusses (2) are all in the same plane; the branch vein trusses (2) in the same group are parallel to each other; The mesophyll skin (3) wraps around the overall structure composed of the main vein truss (1), branch vein trusses (2), and side plates (4).

2. The wing truss structure imitating a willow leaf according to claim 1, characterized in that, The width of the carbon fiber composite rods in the main vein truss is between 1.5 mm and 2 mm; the interval between adjacent carbon fiber composite rods is between 6 mm and 8 mm; the square frame and the internal carbon fiber composite rods have the same thickness, both between 3 mm and 5 mm.

3. The wing truss structure imitating a willow leaf according to claim 1, characterized in that, The included angle between the short inclined rod in the branch vein truss (2) and the carbon fiber composite rod is 30° to 60°.

4. The wing truss structure imitating a willow leaf as claimed in claim 1, wherein The width of the branch vein truss is between 1.2 mm and 1.7 mm, and the distance between adjacent branch vein trusses is between 15 mm and 22 mm; the thickness of the branch vein truss is the same as that of the main vein truss, between 3 mm and 5 mm.

5. The wing truss structure imitating a willow leaf according to claim 1, characterized in that, The main vein truss (1) is made of a composite material with a stiffness greater than or equal to 91 GPa and a tensile strength greater than or equal to 3500 MPa.

6. The wing truss structure imitating a willow leaf according to claim 1, characterized in that, The branch vein truss (2) is made of a composite material with a stiffness greater than or equal to 91 GPa and a tensile strength greater than or equal to 3500 MPa.

7. The wing truss structure imitating a willow leaf according to claim 1, characterized in that, The mesophyll skin (3) is made of a flexible skin material.

8. The wing truss structure imitating a willow leaf according to claim 1, characterized in that, After the mesophyll skin (3) wraps the overall structure, the whole becomes a box shape, improving the torsional resistance.

9. The wing truss structure imitating a willow leaf according to claim 8, characterized in that, The mesophyll skin (3) is made to be in close contact with the main vein truss (1), branch vein trusses (2), side plates (4), and mesophyll skin (3) through a heater, and it is necessary to ensure that there is no air flow out between the main vein truss (1) and the branch vein trusses (2), and between the main vein truss (1) and the side plates (4); and it is necessary to ensure that the mesophyll skin (3) between the main vein truss (1) and the branch vein trusses (2), between the main vein truss (1) and the side plates (4), and between different branch vein trusses (2) is tightened.

10. A wing truss structure imitating a willow leaf as described in claim 1, characterized in that, The main vein truss (1) and the two side plates (4) are adhered together with glue.

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