EVTOL aircraft lightweight paddle based on honeycomb structure and manufacturing method

Abstract

The invention provides an eVTOL aircraft lightweight paddle based on a honeycomb structure. The eVTOL aircraft lightweight paddle comprises a main force bearing frame and a skin. The main bearing frame is of a honeycomb structure, the honeycomb structure conforms to gradient distribution, the honeycomb structure is composed of polygonal honeycomb units, and the polygonal honeycomb units have characteristic parameters meeting gradient distribution. The main force bearing frame is made of composite core materials, and the types of the composite core materials are differentially configured according to application scenes. The skin covers the main force bearing frame to form a continuous outer surface, and the main force bearing frame and the skin balance aerodynamic loads and structural deformation through a multi-objective optimization algorithm. The invention further provides a manufacturing method of the eVTOL aircraft lightweight paddle based on the honeycomb structure. According to the method, topological optimization of the honeycomb structure is conducted through the parameterized model, differential selection is achieved through collaborative configuration of the multifunctional material system, and the compression molding technology and the 3D printing technology are used for meeting different manufacturing requirements.

Description

Technical Field

[0001] The present invention relates to the technical field of aircraft, and particularly to an aircraft blade and a manufacturing method thereof. Background Art

[0002] In the technical field of electric vertical takeoff and landing (eVTOL) aircraft, the rotor blade, as a core lift component, its structural design and material selection directly affect the thrust-to-weight ratio, endurance, and safety performance of the aircraft. The current mainstream technologies generally adopt blade structures based on metal alloys or solid composite materials. Typical solutions include integral casting of aluminum alloy and solid lamination process of carbon fiber reinforced polymer (CFRP). Although such solutions achieve the necessary structural strength through high-density materials, there are the following technical bottlenecks: First, there is an imbalance between mass and efficiency. Taking a solid carbon fiber blade as an example, its material density is maintained in the range of 1.8 - 2.0 g / cm³, resulting in an increase in the mass of a single blade by about 25%, and reducing the effective range under typical mission conditions by 15% - 20%, seriously restricting the economy of commercial operation. Second, the aerodynamic-structure coupling effect is significant. The solid cross-section is difficult to optimize the internal stress distribution, and it is easy to cause turbulent boundary layer separation during high-speed rotation. Third, the existing lightweight solutions have defects in structural integrity. Although traditional hollow blades can achieve a weight reduction effect of 20% - 30%, limited by the manufacturing process, they generally adopt a single continuous cavity design. The above problems make it difficult for the existing technologies to meet the commercial endurance requirements, and there is an urgent need to realize the coordinated improvement of lightweight, high stiffness, and aerodynamic stability through material distribution optimization and multi-scale structural innovation. Summary of the Invention

[0003] The present invention proposes a lightweight blade for an eVTOL aircraft based on a honeycomb structure and a manufacturing method thereof. Through parametric models and intelligent algorithms, topological optimization of the honeycomb structure is carried out, and through the collaborative configuration of a multi-functional material system, differential selection of composite core materials is realized, and molding processes and 3D printing technologies are used to meet different manufacturing requirements.

[0004] To achieve the above object, the present invention provides a lightweight blade for an eVTOL aircraft based on a honeycomb structure, including,

[0005] A main load-bearing frame, the structure of the main load-bearing frame is a honeycomb structure, the honeycomb structure conforms to a gradient distribution, the honeycomb structure is composed of polygonal honeycomb units, and the polygonal honeycomb units have characteristic parameters that satisfy the gradient distribution. The characteristic parameters include the number of sides, side length, wall thickness, and distribution position of the polygonal honeycomb units;

[0006] The material of the main load-bearing frame is a composite core material, the composite core material includes titanium alloy and glass fiber reinforced polypropylene, and the types of the composite core material are differentially configured according to the application scenario;

[0007] A skin that covers the main load-bearing frame to form a continuous outer surface, and the main load-bearing frame and the skin balance the aerodynamic load and structural deformation through a multi-objective optimization algorithm.

[0008] In one embodiment, the main load-bearing frame includes a root region and a tip region. The structures of the root region and the tip region are honeycomb structures. Among them, the root region is a high-density honeycomb unit, and the tip region is a low-density honeycomb unit. The honeycomb structure conforms to a gradient distribution. From the root region to the tip region, the density of honeycomb units gradually decreases, and the length of honeycomb units gradually decreases.

[0009] In one embodiment, the polygonal honeycomb units include Hexagonal honeycomb units with characteristic parameters that satisfy a gradient distribution. The side length of the hexagonal honeycomb units is 5 - 10 mm, and the wall thickness of the hexagonal honeycomb units is 0.2 - 0.5 mm; Triangular honeycomb units with characteristic parameters that satisfy a gradient distribution. The side length of the triangular honeycomb units is 4 - 8 mm, and the wall thickness of the triangular honeycomb units is 0.3 - 0.6 mm.

[0010] In one embodiment, the skin is a carbon fiber reinforced composite prepreg, and the surface of the carbon fiber reinforced composite prepreg is coated with a polyurethane anti-impact layer.

[0011] In one embodiment, the types of composite core materials are configured differently according to the application scenarios. If it is applicable to long-distance heavy-load scenarios, the type of composite core material is titanium alloy, and the molding process is compression molding. If it is applicable to short-distance light-load scenarios, the type of composite core material is glass fiber reinforced polypropylene, and the molding process is compression molding.

[0012] In one embodiment, the curved surface area of the main load-bearing frame and the skin is a complex curved surface area. The 3D printing technology, specifically the continuous fiber 3D printing technology, is used to achieve the integrated molding of the main load-bearing frame - skin.

[0013] The present invention provides a manufacturing method for a lightweight blade of an eVTOL aircraft based on a honeycomb structure, including S1. Design the honeycomb structure. Select software to simulate the load distribution of the blade. Based on the simulation results, design the honeycomb structure and use a parametric modeling tool to generate a honeycomb structure distribution map; S2. Prepare the skin. Select carbon fiber prepreg, cut the carbon fiber prepreg, lay up the cut carbon fiber prepreg, and coat a polyurethane anti-impact coating on the surface of the laid-up carbon fiber prepreg; S3. Prepare the main load-bearing frame, configure the types of the composite core materials according to different application scenarios, and prepare the main load-bearing frame; S4. Integrate the main load-bearing frame-skin. If it is applicable to simple curved surface areas, use the compression molding process; if it is applicable to complex curved surface areas, use 3D printing technology.

[0014] In one embodiment, the S1 includes S11. Use finite element analysis software to simulate the load distribution of the blade, and determine the honeycomb density gradient from the root to the tip; S12. Select polygonal honeycomb cells The polygonal honeycomb cells are hexagonal honeycomb cells. The hexagonal honeycomb cells have characteristic parameters that satisfy the gradient distribution. The side length of the hexagonal honeycomb cells is 5-10 mm, and the wall thickness of the hexagonal honeycomb cells is 0.2-0.5 mm; or The polygonal honeycomb cells are triangular honeycomb cells. The triangular honeycomb cells have characteristic parameters that satisfy the gradient distribution. The side length of the triangular honeycomb cells is 4-8 mm, and the wall thickness of the triangular honeycomb cells is 0.3-0.6 mm; S13. Use parametric modeling tools to generate a honeycomb distribution map to make the honeycomb structure dynamically match the aerodynamic load.

[0015] In one embodiment, the S3 includes S31. If it is applicable to long-distance heavy-load scenarios, the type of the composite core material is titanium alloy; S32. If it is applicable to short-distance light-load scenarios, the type of the composite core material is glass fiber reinforced polypropylene.

[0016] In one embodiment, the S4 includes S41. If it is applicable to simple curved surface areas, the type of the composite core material is titanium alloy. Use the compression molding process. Under the conditions of a temperature of 180 °C and a pressure of 10 MPa, co-cure the titanium alloy composite core material and the skin to ensure that the shear strength of the main load-bearing frame-skin interface is ≥25 MPa; S42. If it is applicable to simple curved surface areas, the type of the composite core material is glass fiber reinforced polypropylene. Use the compression molding process. Under the conditions of a temperature of 120 °C and a pressure of 5 MPa, perform surface plasma treatment on the composite core material and the skin to ensure that the shear strength of the main load-bearing frame-skin interface is ≥18 MPa; S43. If it is applicable to complex curved surface areas, use 3D printing technology. Use a continuous fiber 3D printing device and print by layer-by-layer depositing carbon fiber-thermoplastic matrix composite materials, control the printing accuracy, and realize the integrated molding of the main load-bearing frame-skin.

[0017] The present invention has the following beneficial effects: The present invention proposes a lightweight blade for an eVTOL aircraft based on a honeycomb structure and a manufacturing method. At the structural design level, through parametric models and intelligent algorithms to drive the topological optimization of the honeycomb structure, the dynamic adjustment of polygonal honeycomb cells, density distribution, and wall thickness parameters is realized, which not only significantly improves the aerodynamic load adaptability of the blade, but also can flexibly switch alternative honeycomb structures according to the stress field changes, effectively avoiding the local buckling risk of the traditional single-cavity hollow structure. At the material system level, a collaborative configuration mechanism for integrated forming of the main load-bearing frame and skin is constructed. The skin adopts a composite design with a carbon fiber-reinforced composite material coating, which endows excellent environmental tolerance while ensuring high stiffness. The main load-bearing frame realizes differential material selection based on a multi-objective optimization algorithm, enabling materials such as titanium alloy and glass fiber-reinforced polymer to accurately match the diverse scenario requirements of heavy load, light load, etc. At the manufacturing process level, the innovative use of the compression molding process and 3D printing technology realizes the efficient mass production of simple curved surfaces through the optimization of the compression molding process, and combines continuous fiber 3D printing technology to break through the integrated forming of complex curved surface areas. Through the systematic innovation of structure-material-process, the invention forms a full-chain technical barrier covering design, manufacturing, and testing, and is applicable to 200-500 kg-class eVTOL models. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 FIG. is a schematic structural diagram of a lightweight blade for an eVTOL aircraft based on a honeycomb structure according to an embodiment of the present invention; Figure 2a FIG. is a vertical sectional view of a lightweight blade for an eVTOL aircraft based on a honeycomb structure according to an embodiment of the present invention; Figure 2b FIG. is a horizontal sectional view of a lightweight blade for an eVTOL aircraft based on a honeycomb structure according to an embodiment of the present invention; Figure 3 FIG. is a flowchart of a manufacturing method of a lightweight blade for an eVTOL aircraft based on a honeycomb structure according to an embodiment of the present invention; Figure 4 FIG. is a flowchart of step S1 of a manufacturing method of a lightweight blade for an eVTOL aircraft based on a honeycomb structure according to an embodiment of the present invention; Figure 5 FIG. is a flowchart of step S3 of a manufacturing method of a lightweight blade for an eVTOL aircraft based on a honeycomb structure according to an embodiment of the present invention; Figure 6 FIG. is a flowchart of step S4 of a manufacturing method of a lightweight blade for an eVTOL aircraft based on a honeycomb structure according to an embodiment of the present invention.

[0019] REFERENCE SIGNS 1. Main load-bearing frame; 2. Skin; 11. Root region; 12. Tip region; 111. High-density honeycomb cell; 121. Low-density honeycomb cell. Detailed implementation manners

[0020] In order to make the objectives, technical solutions and advantages of the present invention more clear and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the invention and are not used to limit the invention.

[0021] In order to achieve the above objectives, the present invention provides a lightweight blade for an eVTOL aircraft based on a honeycomb structure, including a main load-bearing frame 1 and a skin 2.

[0022] The structure of the main load-bearing frame 1 is a honeycomb structure, and the honeycomb structure conforms to a gradient distribution. The honeycomb structure is composed of polygonal honeycomb cells, and the polygonal honeycomb cells have characteristic parameters that satisfy the gradient distribution. The characteristic parameters include the number of sides, side length, wall thickness, and distribution position of the polygonal honeycomb cells. The material of the main load-bearing frame 1 is a composite core material, and the composite core material includes titanium alloy and glass fiber-reinforced polypropylene. The types of composite core materials are configured differently according to the application scenarios. The skin 2 covers the main load-bearing frame 1 to form a continuous outer surface, and the main load-bearing frame 1 and the skin 2 balance the aerodynamic load and structural deformation through a multi-objective optimization algorithm. Preferably, the main load-bearing frame 1 and the skin 2 balance the aerodynamic load and structural deformation through a multi-objective optimization algorithm, and the optimization objectives include: interface shear strength ≥ 35 MPa, and the maximum deformation of the skin ≤ 1.5 mm.

[0023] In this embodiment, the main load-bearing frame 1 includes a root region 11 and a tip region. The structures of the root region 11 and the tip region are honeycomb structures. Among them, the root region 11 is a high-density honeycomb cell 111, and the tip region is a low-density honeycomb cell 121. The honeycomb structure conforms to a gradient distribution. From the root region 11 to the tip region, the density of the honeycomb cells gradually decreases, and the length of the honeycomb cells gradually decreases. Preferably, the side length of the high-density honeycomb cell 111 is 5 mm and the wall thickness is 0.5 mm, and the side length of the low-density honeycomb cell 121 is 10 mm and the wall thickness is 0.2 mm. When the high-density honeycomb cells transition to the tip region, the density of the honeycomb cells gradually decreases. By adopting such a honeycomb structure, the mass is reduced by 35% and the flexural stiffness is increased by 30%. Preferably, a parametric modeling software is used to model according to the determined honeycomb cell parameters. During the modeling process, the parameters of the honeycomb structure are accurately correlated with the aerodynamic load distribution of the blade to ensure that the layout of the honeycomb structure dynamically matches the aerodynamic load. By adjusting parameters such as the position, angle, and size of the honeycomb cells, the entire honeycomb structure can effectively disperse and bear the aerodynamic load under different flight conditions, thereby avoiding the buckling risk caused by local stress concentration.

[0024] In this embodiment, the polygonal honeycomb unit includes a hexagonal honeycomb unit and a triangular honeycomb unit. The hexagonal honeycomb unit has characteristic parameters that satisfy a gradient distribution. The side length of the hexagonal honeycomb unit is 5 - 10 mm, and the wall thickness of the hexagonal honeycomb unit is 0.2 - 0.5 mm. The triangular honeycomb unit has characteristic parameters that satisfy a gradient distribution. The side length of the triangular honeycomb unit is 4 - 8 mm, and the wall thickness of the triangular honeycomb unit is 0.3 - 0.6 mm. Preferably, under the condition of characteristic parameters that satisfy a gradient distribution, the hexagonal honeycomb unit can be replaced by a triangular honeycomb configuration. The shear strength of the triangular honeycomb configuration is increased by 15% - 20% compared to the hexagonal honeycomb unit, which is suitable for high - mobility eVTOL models, but the risk of stress concentration caused by the reduction of geometric symmetry needs to be compensated through topological optimization.

[0025] In this embodiment, the skin 2 is a carbon fiber reinforced composite prepreg, and a polyurethane anti - impact layer is coated on the surface of the carbon fiber reinforced composite prepreg. Preferably, the model of the carbon fiber reinforced composite prepreg is Toray T700 standard carbon fiber from Japan. The parameters of the carbon fiber reinforced composite prepreg are as follows: tensile strength ≥ 3.5 Gpa, density 1.6 g / cm³, and the single - layer thickness is 0.15 mm. A 0.2 - mm polyurethane anti - impact layer is coated on the surface of the carbon fiber reinforced composite prepreg to resist foreign object impact. The parameters of the polyurethane anti - impact layer are as follows: Shore hardness is 80D, and anti - impact energy ≥ 1 J.

[0026] In this embodiment, the types of composite core materials are configured differently according to the application scenarios. If it is applicable to long - distance heavy - load scenarios, the type of composite core material is titanium alloy, and the molding process is compression molding. If it is applicable to short - distance light - load scenarios, the type of composite core material is glass fiber reinforced polypropylene, and the molding process is compression molding. Preferably, the type of composite core material is titanium alloy, and the compressive strength ≥ 8 Mpa. The type of composite core material is glass fiber reinforced polypropylene, which reduces the weight by 50% compared to aluminum alloy. The parameters of the composite core material include a density of 0.8 g / cm³ and a compressive strength of 5 MPa.

[0027] In this embodiment, the curved surface area between the main load - bearing frame 1 and the skin 2 is a complex curved surface area. The 3D printing technology, specifically the continuous fiber 3D printing technology, is used to realize the integrated molding of the main load - bearing frame - skin. Preferably, for the complex curved surface area, a continuous fiber 3D printing device is used for supplementary manufacturing. The model of the 3D printing device is Markforged X7. The printing material is carbon fiber (T800 grade). The printing parameters include printing temperature, layer thickness, path spacing, nozzle moving speed, and the accuracy control is ±0.1 mm. The printing path is to generate a spiral progressive filling path from the 3D model to ensure the interlayer bonding strength between the main load - bearing frame and the skin.

[0028] The present invention provides a manufacturing method for a lightweight blade of an eVTOL aircraft based on a honeycomb structure, including, S1. Design a honeycomb structure. Select software to simulate the load distribution of the blade. Based on the simulation results, design the honeycomb structure and use a parametric modeling tool to generate a honeycomb structure distribution map.

[0029] S2. Prepare the skin. Select carbon fiber prepreg, cut the carbon fiber prepreg, lay up the cut carbon fiber prepreg, and coat a polyurethane impact-resistant coating on the surface of the laid-up carbon fiber prepreg.

[0030] S3. Prepare the main load-bearing frame. Differentially configure the types of composite core materials according to the application scenarios and prepare the main load-bearing frame.

[0031] S4. Integrate the main load-bearing frame - skin. If it is applicable to simple curved surface areas, use a compression molding process; if it is applicable to complex curved surface areas, use 3D printing technology.

[0032] In this embodiment, S1 includes: S11. Use finite element analysis software to simulate the load distribution of the blade and determine the honeycomb density gradient from the root to the tip.

[0033] S12. Select polygonal honeycomb cells. The polygonal honeycomb cells are hexagonal honeycomb cells. The hexagonal honeycomb cells have characteristic parameters that satisfy the gradient distribution. The side length of the hexagonal honeycomb cells is 5 - 10 mm, and the wall thickness of the hexagonal honeycomb cells is 0.2 - 0.5 mm; or The polygonal honeycomb cells are triangular honeycomb cells. The triangular honeycomb cells have characteristic parameters that satisfy the gradient distribution. The side length of the triangular honeycomb cells is 4 - 8 mm, and the wall thickness of the triangular honeycomb cells is 0.3 - 0.6 mm.

[0034] S13. Use a parametric modeling tool to generate a honeycomb distribution map to make the honeycomb structure dynamically match the aerodynamic load.

[0035] Preferably, use the finite element analysis software ANSYS Mechanical to simulate the aerodynamic load of the blade and analyze the stress distribution under hovering, cruising, and extreme working conditions. Determine the honeycomb structure density gradient according to the stress distribution results: the honeycomb density is the highest in the root area and gradually decreases along the span direction towards the tip to meet the requirements of bending stiffness and lightweight. Simulate the load distribution of the blade under different flight conditions through software, and determine that the polygonal honeycomb cells are hexagonal honeycomb cells according to the load distribution structure. Generate a honeycomb structure distribution map through a parametric modeling tool. The parametric modeling tool can be selected as ANSYS Workbench or CATIA. During the design process, the software will dynamically adjust the honeycomb parameters according to the aerodynamic load to ensure the matching of the structure and the load. Through the visualization function of the software, the changes of the honeycomb structure can be intuitively observed to optimize the design parameters.

[0036] In this embodiment, S3 includes: S31 If it is applicable to the long-distance heavy-load scenario, the type of the composite core material is titanium alloy.

[0037] S32 If it is applicable to the short-distance light-load scenario, the type of the composite core material is glass fiber reinforced polypropylene.

[0038] In this embodiment, S4 includes: S41 If it is applicable to the simple curved surface area, the type of the composite core material is titanium alloy. Using the compression molding process, under the conditions of a temperature of 180°C and a pressure of 10 MPa, co-cure the titanium alloy composite core material and the skin to ensure that the shear strength of the main load-bearing frame-skin interface is ≥25 MPa.

[0039] S42 If it is applicable to the simple curved surface area, the type of the composite core material is glass fiber reinforced polypropylene. Using the compression molding process, under the conditions of a temperature of 120°C and a pressure of 5 MPa, perform surface plasma treatment on the composite core material and the skin to ensure that the shear strength of the main load-bearing frame-skin interface is ≥18 MPa.

[0040] S43 If it is applicable to the complex curved surface area, adopt 3D printing technology, use a continuous fiber 3D printing device, and print by layer-by-layer depositing carbon fiber-thermoplastic matrix composite materials, control the printing accuracy, and realize the integrated molding of the main load-bearing frame and the skin.

[0041] There is also an alternative solution in step S4 of the present invention, that is, the micro-foaming injection molding process. This process includes: selecting materials, selecting aramid paper honeycomb core materials with appropriate specifications and thermoplastic polyurethane for micro-foaming injection. Using an injection molding machine, set appropriate injection molding machine parameters, including injection pressure, speed, and holding pressure parameters. Using supercritical carbon dioxide foaming, control the injection amount and time, and inhibit the foaming rate. The operation process includes: putting the pretreated aramid paper honeycomb core material into the mold and fixing it, injecting molten thermoplastic polyurethane, observing the parameters to ensure stability. After holding pressure, cool the product and take out the molded blade. The molding cycle of this process is shortened to 20 minutes, which is suitable for large-scale production, but the foaming rate needs to be controlled ≤10% to avoid the influence of the porosity on the stiffness.

[0042] The present invention has the following beneficial effects: The present invention proposes a lightweight blade for an eVTOL aircraft based on a honeycomb structure and a manufacturing method. At the structural design level, through the parametric model and intelligent algorithm-driven topological optimization of the honeycomb structure, the dynamic adjustment of the polygonal honeycomb unit, density distribution, and wall thickness parameters is realized, which not only significantly improves the aerodynamic load adaptability of the blade but also can flexibly switch to alternative honeycomb structures according to the stress field changes, effectively avoiding the local buckling risk of the traditional single-cavity hollow structure. At the material system level, a collaborative configuration mechanism for integrated forming of the main load-bearing frame and skin is constructed. The skin adopts a composite design with a carbon fiber-reinforced composite material coating, which endows excellent environmental tolerance while ensuring high stiffness, and the main load-bearing frame realizes differential material selection based on a multi-objective optimization algorithm, enabling materials such as titanium alloy and glass fiber-reinforced polymer to accurately match the diverse scenario requirements of heavy load, light load, etc. At the manufacturing process level, the innovative use of the compression molding process and 3D printing technology realizes the high-efficiency mass production of simple curved surfaces through the optimization of the compression molding process, and combines the continuous fiber 3D printing technology to break through the integrated forming of complex curved surface areas. Through the systematic innovation of structure-material-process, the invention forms a full-chain technical barrier covering design, manufacturing, and testing, and is applicable to 200-500 kg class eVTOL models.

[0043] It should be noted that unless otherwise clearly specified and limited, the similar terms such as "installation", "connection", and "coupling" used in the description of this application should be understood in a broad sense. For example, the connection can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can also be the communication inside two components. Those skilled in the art can understand its specific meaning in this application according to the specific situation.

[0044] The above embodiments are only further descriptions of the present invention, not other forms of limitation to the present invention. The present invention can also have other various embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding modifications and changes according to the present invention, but these corresponding modifications and changes should all fall within the protection scope of the present invention.

Claims

1. A lightweight blade for an eVTOL aircraft based on a honeycomb structure, characterized in that, including a main load-bearing frame, the structure of the main load-bearing frame is a honeycomb structure, the honeycomb structure conforms to a gradient distribution, the honeycomb structure is composed of polygonal honeycomb units, the polygonal honeycomb units have characteristic parameters that satisfy the gradient distribution, and the characteristic parameters include the number of sides, side length, wall thickness, and distribution position of the polygonal honeycomb units; the material of the main load-bearing frame is a composite core material, the composite core material includes titanium alloy and glass fiber reinforced polypropylene, and the types of the composite core material are configured differently according to the application scenarios; a skin, the skin covers the main load-bearing frame to form a continuous outer surface, and the main load-bearing frame and the skin balance the aerodynamic load and structural deformation through a multi-objective optimization algorithm.

2. The lightweight blade of the eVTOL aircraft based on the honeycomb structure according to claim 1, wherein The main load-bearing frame includes a root region and a tip region, and the structures of the root region and the tip region are honeycomb structures. Among them, the root region is a high-density honeycomb unit, and the tip region is a low-density honeycomb unit. The honeycomb structure conforms to a gradient distribution. From the root region to the tip region, the density of the honeycomb units gradually decreases, and the length of the honeycomb units gradually decreases.

3. The lightweight blade of the eVTOL aircraft based on the honeycomb structure according to claim 2, wherein, The polygonal honeycomb units include hexagonal honeycomb units, the hexagonal honeycomb units have characteristic parameters that satisfy the gradient distribution, the side length of the hexagonal honeycomb units is 5-10 mm, and the wall thickness of the hexagonal honeycomb units is 0.2-0.5 mm; triangular honeycomb units, the triangular honeycomb units have characteristic parameters that satisfy the gradient distribution, the side length of the triangular honeycomb units is 4-8 mm, and the wall thickness of the triangular honeycomb units is 0.3-0.6 mm.

4. The lightweight blade of the eVTOL aircraft based on the honeycomb structure according to claim 1, characterized in that, The skin is a carbon fiber reinforced composite prepreg, and the surface of the carbon fiber reinforced composite prepreg is coated with a polyurethane anti-impact layer.

5. The lightweight blade of the eVTOL aircraft based on the honeycomb structure according to claim 1, characterized in that, The types of the composite core material are configured differently according to the application scenarios; if applicable to the long-distance heavy-load scenario, the type of the composite core material is titanium alloy, and the molding process is compression molding. If applicable to the short-distance light-load scenario, the type of the composite core material is glass fiber reinforced polypropylene, and the molding process is compression molding.

6. The lightweight blade of the eVTOL aircraft based on the honeycomb structure according to claim 1, wherein The curved surface area of the main load-bearing frame and the skin is a complex curved surface area. The 3D printing technology, specifically the continuous fiber 3D printing technology, is used to realize the integrated molding of the main load-bearing frame-skin.

7. A manufacturing method for a lightweight blade of an eVTOL aircraft based on a honeycomb structure, characterized in that, including S1. Design the honeycomb structure, select software to simulate the load distribution of the blade, design the honeycomb structure based on the simulation results, and use a parametric modeling tool to generate a honeycomb structure distribution map; S2. Prepare the skin, select carbon fiber prepreg, cut the carbon fiber prepreg, lay up the cut carbon fiber prepreg, and coat a polyurethane anti-impact coating on the surface of the laid-up carbon fiber prepreg; S3. Prepare the main load-bearing frame, configure the types of the composite core material differently according to the application scenarios, and prepare the main load-bearing frame; S4. Integrate the main load-bearing frame-skin. If applicable to the simple curved surface area, the compression molding process is adopted; If applicable to the complex curved surface area, the 3D printing technology is adopted.

8. The manufacturing method of a lightweight blade for an eVTOL aircraft based on a honeycomb structure according to claim 7, characterized in that, The S1 includes S11. Use finite element analysis software to simulate the load distribution of the blade and determine the honeycomb density gradient from the root to the tip; S12. Select polygonal honeycomb units The polygonal honeycomb unit is a hexagonal honeycomb unit. The hexagonal honeycomb unit has characteristic parameters that satisfy a gradient distribution. The side length of the hexagonal honeycomb unit is 5 - 10 mm, and the wall thickness of the hexagonal honeycomb unit is 0.2 - 0.5 mm; or The polygonal honeycomb unit is a triangular honeycomb unit. The triangular honeycomb unit has characteristic parameters that satisfy a gradient distribution. The side length of the triangular honeycomb unit is 4 - 8 mm, and the wall thickness of the triangular honeycomb unit is 0.3 - 0.6 mm; S13 Use a parametric modeling tool to generate a honeycomb distribution map to dynamically match the honeycomb structure with the aerodynamic load.

9. The manufacturing method of a lightweight blade of an eVTOL aircraft based on a honeycomb structure according to claim 7, characterized in that, The S3 includes, S31 If it is applicable to the long - distance heavy - load scenario, the type of composite core material is titanium alloy; S32 If it is applicable to the short - distance light - load scenario, the type of composite core material is glass fiber - reinforced polypropylene.

10. The manufacturing method of a lightweight blade of an eVTOL aircraft based on a honeycomb structure according to claim 7, characterized in that, The S4 includes, S41 If it is applicable to the simple curved surface area, the type of composite core material is titanium alloy. Adopt the compression molding process. Under the conditions of a temperature of 180 °C and a pressure of 10 MPa, co - cure the titanium alloy composite core material with the skin to ensure that the shear strength of the main load - bearing frame - skin interface is ≥ 25 MPa; S42 If it is applicable to the simple curved surface area, the type of composite core material is glass fiber - reinforced polypropylene. Adopt the compression molding process. Under the conditions of a temperature of 120 °C and a pressure of 5 MPa, perform surface plasma treatment on the composite core material and the skin to ensure that the shear strength of the main load - bearing frame - skin interface is ≥ 18 MPa; S43 If it is applicable to the complex curved surface area, adopt 3D printing technology. Use a continuous fiber 3D printing device to print by layer - by - layer depositing carbon fiber - thermoplastic matrix composite materials, control the printing accuracy, and achieve the integrated molding of the main load - bearing frame - skin.

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