Design method of bionic vein structure of large fan blade

Abstract

The invention relates to the technical field of fan blades, and discloses a design method of a bionic vein structure of a large fan blade. Comprising the following steps of wind turbine blade virtual partition and vein feature parameter extraction, blade virtual partition bionic vein structure design, composite material application and thickness design, performance analysis and fatigue evaluation, optimization design and verification and testing. Bionic optimization design of the fan blade structure is achieved through virtual partitioning and plant vein feature parameter extraction, the aerodynamic performance and the structural performance of the blade are improved, the anti-fatigue capacity of the blade is remarkably enhanced, the service time is prolonged, and through application and thickness design of the composite material, the service life of the blade is prolonged. And the overall performance of the blade is further improved. Besides, according to the method, comprehensive optimization design is carried out on the blade through performance analysis and fatigue evaluation, stable operation of the blade in a complex environment is ensured, and the probability of occurrence of safety accidents is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of fan blades, and in particular to a design method for a bionic vein structure of a large fan blade. Background Art

[0002] Horizontal-axis wind turbines have become the mainstream type of modern commercial wind power generation due to their relatively high wind energy utilization rate. In order to reduce the cost per kilowatt-hour, the diameter of wind turbine rotors has increased from 15m in the 1980s to more than 200m today, making it the largest rotating machine ever built by humans.

[0003] In recent years, with the shortage of energy and the policy support of various countries for the wind power industry, the global installed capacity of wind power generation has increased significantly. Faced with the rapid rise in wind energy demand in the current society, the problems of traditional wind power have gradually emerged: traditional blades are subject to the interaction of aerodynamic loads, gravity loads and inertial loads during rotation, and as the blades become larger and more flexible, they are prone to vibration during service. Strong vibrations lead to a decrease in the fatigue resistance of the blades, shortened service time, and even damage causing safety accidents such as blade breakage. Therefore, it is necessary to propose a new design method for the bionic vein structure of large wind turbine blades. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides a design method for a bionic vein structure of a large fan blade to solve the background technical problems.

[0005] To achieve the above object, the present invention provides the following technical solution: The method is used to design a bionic vein structure of a large wind turbine blade, specifically comprising the following steps:

[0006] Step 1: Virtual partitioning of wind turbine blades and extraction of vein feature parameters

[0007] Virtual partitioning of blades: Divide the fan blades evenly into N partitions along the radial direction from the blade tip to the center of rotation, and each partition has a total length of L blade 1 / N of the partition boundary line along the blade rotation trajectory, ensuring that the mechanical behavior of each partition under wind load is relatively independent;

[0008] Extraction of leaf vein characteristic parameters: Select plant leaf veins with excellent mechanical properties and aerodynamic characteristics, and extract key parameters of the leaf vein network, including: main vein diameter d main植物 , branching angle θ branch植物 , veinlet spacing s fine植物 , veinlet diameter d fine植物 ; These parameters are used to guide the design of bionic leaf vein structure.

[0009] Step 2: Design of bionic vein structure of each virtual partition of the leaf

[0010] Based on the parameters of plant veins, these parameters are proportionally amplified or adjusted according to the leaf size and performance requirements to obtain the bionic vein parameters suitable for wind turbine blades: the main vein diameter d min (x) = k d ·d main植物 f(x), branching angle θ branch =θ branch植物 , veinlet spacing s fine =k s ·s fine植物 , veinlet diameter d fine = k′ d ·d fine植物 , where k s and k d is the geometric magnification factor, k′ d is the adjustment coefficient of the veinlet diameter, f(x) is a decreasing function of the leaf length x, which is used to describe the variation of the main vein diameter along the leaf length;

[0011] Main vein path planning: Design a continuous and smooth main vein path along the length of the blade. The main vein diameter d main (x) gradually decreases along the blade length x; the change relationship satisfies Where g(x) is a decreasing function;

[0012] Design of branches and veins: Based on the main vein path, according to the branch angle θ branch Evenly arrange branches, the number of branches is n branch (i) is a constant in each partition, where i is the partition number; the veinlets start from the branch veins and are calculated according to the veinlet spacing s. fine and veinlet diameter d fine The patterns are arranged in a regular pattern, forming a network distribution that covers the entire leaf area.

[0013] Step 3: Composite material application and thickness design

[0014] Composite material selection: choose a material with a tensile strength of σ t A composite material with an elastic modulus of E is used as the main material of the blade;

[0015] Layer design: Based on the bionic leaf vein structure, the layering sequence and thickness distribution of the composite material are designed. The main part of the blade adopts alternating layers, and the thickness of each layer is t layer , total number of layers n layer Determined by calculation based on blade length and required strength.

[0016] Step 4: Performance Analysis and Fatigue Assessment

[0017] Aerodynamic performance analysis: Using CFD software to simulate wind speed v windAerodynamic performance of the bionic blade and calculation of lift coefficient C L and the drag coefficient C D , and wind energy conversion efficiency η wind ;

[0018] Structural performance analysis: The finite element analysis method is used to conduct static analysis on the bionic blade to evaluate its stress distribution and deformation under extreme load;

[0019] Fatigue analysis: Based on the service environment and load spectrum of the blade, fatigue analysis software is used to predict the fatigue life of the bionic blade. f .

[0020] Step 5: Optimize the design

[0021] Parameter optimization: Based on performance analysis and fatigue assessment, the parameters of the bionic leaf vein structure are optimized and adjusted to further improve the aerodynamic and structural performance of the blade;

[0022] Composite material optimization: According to the structural optimization results, the plying order and thickness distribution of the composite material are adjusted to match the optimized vein structure and optimize the overall performance of the blade.

[0023] Preferably, the specific method of the optimization design in step 5 includes:

[0024] Parameter Optimization

[0025] Data collection and analysis: First, collect all relevant data for performance analysis and fatigue assessment, including aerodynamic performance, structural performance, and fatigue life prediction results;

[0026] Parameter adjustment: Based on the data analysis results, the parameters of the bionic leaf vein structure are optimized and adjusted; this includes adjusting the parameters of the main vein diameter, branching angle of the side veins, veinlet diameter and veinlet spacing.

[0027] Composite material optimization

[0028] Layer sequence adjustment: adjust the layer sequence of composite materials according to the structural optimization results;

[0029] Thickness distribution optimization: At the same time, the thickness distribution of the composite material is adjusted according to the optimized leaf vein structure;

[0030] Material selection: Consideration is also given to replacing composite materials with better properties to further improve the overall performance of the blade.

[0031] Comprehensive evaluation and optimization

[0032] Overall performance evaluation: After each optimization iteration, the overall performance of the blade is comprehensively evaluated, including aerodynamic performance, structural performance, and fatigue life;

[0033] Design optimization: Based on the comprehensive evaluation results, the blade design is further optimized to achieve the best overall performance.

[0034] Preferably, the method further includes step 6, verification and testing:

[0035] Prototype manufacturing: According to the optimized design, the prototype of the blade is manufactured;

[0036] Experimental verification: Experimental verification of the prototype blades, including aerodynamic performance tests, structural performance tests, and fatigue life tests;

[0037] Result analysis: Analyze the effectiveness of the optimized design based on the experimental results, and make further adjustments and optimizations as needed.

[0038] Preferably, after each optimization iteration, the stiffness, ultimate strength and vibration instability performance of the blade are comprehensively evaluated, and the design is further optimized based on the evaluation results to optimize the overall performance of the blade.

[0039] Preferably, after the performance analysis and fatigue assessment steps are completed, the results of the performance analysis and fatigue analysis are used to compare the aerodynamic performance, structural performance, fatigue life and vibration characteristics of the bionic blades and traditional blades; specifically, by quantitatively analyzing the parameters of the bionic blades in improving wind energy conversion efficiency, reducing the drag coefficient, enhancing structural stiffness, improving the ultimate bearing capacity, extending fatigue life and controlling vibration instability, optimization ideas are provided for the optimization design.

[0040] Preferably, during the optimization design stage, the manufacturing process and cost factors of the blades are also considered, and the optimal balance between blade performance, cost and environment is achieved by comprehensively evaluating the feasibility, economy and environmental friendliness of the design solution.

[0041] Preferably, in step six, the experimental verification of the prototype blades also includes simulating the blade performance under extreme weather conditions, and evaluating the durability and reliability of the blades in harsh environments such as sand, dust, and salt spray.

[0042] Compared with the prior art, the present invention has the following beneficial effects:

[0043] 1. The present invention realizes the bionic optimization design of the fan blade structure through virtual partitioning and extraction of plant vein characteristic parameters; this method not only improves the aerodynamic performance and structural performance of the blade, but also significantly enhances the fatigue resistance of the blade and prolongs the service time; through the application of composite materials and thickness design, the overall performance of the blade is further improved; in addition, this method also comprehensively optimizes the blade through performance analysis and fatigue evaluation, ensuring the stable operation of the blade in a complex environment and reducing the probability of safety accidents.

[0044] 2. During the optimization design stage, the present invention fully considered the performance of the blades under extreme weather conditions and harsh environments; through simulation experiments, it was verified that the bionic blades exhibited good durability and reliability, and were able to maintain stable power generation efficiency in harsh environments such as sandstorms and salt spray, reducing downtime and maintenance costs caused by environmental factors.

[0045] 3. Through the design and optimization of the bionic leaf vein structure, the aerodynamic performance, structural performance and fatigue life of the blades are significantly improved in the present invention; the bionic blades can capture wind energy more efficiently, reduce the drag coefficient, while enhancing structural stiffness, improving the ultimate bearing capacity, and extending the service life, bringing revolutionary progress to the field of wind power generation.

[0046] 4. After each optimization iteration, the present invention conducts a comprehensive evaluation of the overall performance of the blade, focusing not only on aerodynamic performance, structural performance and fatigue life, but also on key indicators such as stiffness, ultimate strength and vibration instability; by quantitatively analyzing the performance of bionic blades in various aspects, precise guidance is provided for optimization design, the comprehensive performance of the blade is optimized, and the requirements of the complex and changeable service environment are met. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 This is a flow chart of the design method of the bionic vein structure of a large fan blade of the present invention;

[0048] Figure 2 This is a schematic diagram of the bionic veins of the fan blade of the present invention. DETAILED DESCRIPTION

[0049] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0050] See also Figure 1 and Figure 2 The design method of the bionic vein structure of a large wind turbine blade includes the following steps:

[0051] Step 1: Virtual partitioning of wind turbine blades and extraction of vein feature parameters

[0052] Virtual partitioning of blades: Divide the fan blades evenly into N partitions along the radial direction from the blade tip to the center of rotation, and each partition is approximately the total length L blade The partition boundary line is along the blade rotation trajectory, ensuring that the mechanical behavior of each partition under wind load is relatively independent; this helps to more accurately analyze the stress conditions of each partition and provide accurate data support for subsequent bionic design.

[0053] Extraction of leaf vein characteristic parameters: Select plant leaf veins with excellent mechanical properties and aerodynamic characteristics, and extract key parameters of the leaf vein network, including: main vein diameter dmain植物 , branching angle θ branch植物 , veinlet spacing s fine植物 , veinlet diameter d fine植物 ; These parameters are used to guide the design of bionic leaf vein structure; by imitating the structure of plant leaf veins, the fan blades can be given better mechanical properties and aerodynamic characteristics.

[0054] Step 2: Design of bionic vein structure of each virtual partition of the leaf

[0055] Based on the parameters of plant veins, these parameters are proportionally amplified or adjusted according to the leaf size and performance requirements to obtain the bionic vein parameters suitable for wind turbine blades: the main vein diameter d min (x) = k d ·d main植物 f(x), branching angle θ branch =θ branch植物 , veinlet spacing s fine =k s ·s fine植物 , veinlet diameter d fine = k′ d ·d fine植物 , where k s and k d is the geometric magnification factor, k′ d is the adjustment coefficient of the vein diameter, f(x) is a decreasing function of the blade length x, and is used to describe the variation of the main vein diameter along the blade length. According to the blade size and performance requirements, the parameters of the plant veins are proportionally amplified or adjusted with specific functions to obtain the bionic vein parameters suitable for wind turbine blades. This design enables the blade to distribute stress more evenly when subjected to force, thereby improving its carrying capacity. At the same time, by adjusting the variation of the main vein diameter along the blade length, the aerodynamic performance of the blade can be further optimized.

[0056] Main vein path planning: Design a continuous and smooth main vein path along the length of the blade. The main vein diameter d main (x) gradually decreases along the blade length x; the change relationship satisfies Where g(x) is a decreasing function; the continuous and smooth main vein path ensures that the blades can remain stable when subjected to force; this helps to reduce blade vibration and noise and improve the operating efficiency of the entire machine.

[0057] Design of branches and veins: Based on the main vein path, according to the branch angle θ branch Evenly arrange branches, the number of branches is n branch (i) is a constant in each partition, where i is the partition number; the veinlets start from the branch veins and are calculated according to the veinlet spacing s. fine and veinlet diameter d fineThe main veins are arranged on the basis of the main vein path to form a network distribution, covering the entire blade area. This design not only enhances the structural strength of the blade, but also improves its fatigue resistance. By optimizing the layout and parameters of the branch veins and fine veins, the aerodynamic performance of the blade can be further improved, and the wind energy conversion efficiency can be improved.

[0058] Step 3: Composite material application and thickness design

[0059] Composite material selection: choose a material with a tensile strength of σ t A composite material with an elastic modulus of E is used as the main material of the blade; this material has the advantages of light weight, high strength, and corrosion resistance, and can meet the high requirements of wind turbine blades on material performance; by reasonably selecting composite materials, the reliability and durability of the blade can be further improved.

[0060] Layer design: Based on the bionic leaf vein structure, the layering sequence and thickness distribution of the composite material are designed. The main part of the blade adopts alternating layers, and the thickness of each layer is t layer , total number of layers n layer It is determined by calculation based on the blade length and required strength; this design enables the blade to more effectively transfer and disperse stress when subjected to force, thereby improving its load-bearing capacity; at the same time, by optimizing the laying sequence and thickness distribution, the aerodynamic performance of the blade can be further improved and the drag coefficient can be reduced.

[0061] Step 4: Performance Analysis and Fatigue Assessment

[0062] Aerodynamic performance analysis: Using CFD software to simulate wind speed v wind Aerodynamic performance of the bionic blade and calculation of lift coefficient C L and the drag coefficient C D , and wind energy conversion efficiency η wind This analysis can intuitively reflect the aerodynamic performance of the blades and provide a strong basis for optimizing the design. By continuously optimizing the aerodynamic performance, the power generation efficiency and economic benefits of the wind turbine can be further improved.

[0063] Structural performance analysis: The finite element analysis method is used to conduct static analysis on the bionic blade to evaluate its stress distribution and deformation under extreme loads; this analysis can ensure the safety and reliability of the blade under extreme working conditions; by timely discovering and repairing potential structural problems, safety accidents and economic losses caused by blade failure can be avoided.

[0064] Fatigue analysis: Based on the service environment and load spectrum of the blade, fatigue analysis software is used to predict the fatigue life of the bionic blade. fThis analysis can predict the fatigue damage of blades during long-term operation, providing a scientific basis for formulating maintenance plans and replacement strategies; by replacing fatigue-damaged blades in a timely manner, the continuous and stable operation of the wind turbine can be ensured.

[0065] Using the results of performance analysis and fatigue analysis, the aerodynamic performance, structural performance, fatigue life and vibration characteristics of bionic blades are compared with traditional blades. Specifically, by quantitatively analyzing the parameters of bionic blades in improving wind energy conversion efficiency, reducing drag coefficient, enhancing structural stiffness, improving ultimate bearing capacity, extending fatigue life and controlling vibration instability, optimization ideas are provided for optimal design.

[0066] Step 5: Optimize the design

[0067] Parameter optimization: Based on performance analysis and fatigue assessment, the parameters of the bionic leaf vein structure (such as main vein diameter, branching angle of branch veins, fine vein density, etc.) are optimized and adjusted to further improve the aerodynamic and structural performance of the blade;

[0068] Specifically:

[0069] Data collection and analysis: First, all relevant data for performance analysis and fatigue assessment are collected, including aerodynamic performance (such as lift coefficient, drag coefficient, wind energy conversion efficiency), structural performance (such as stress distribution, deformation) and fatigue life prediction results; through in-depth analysis of these data, it is possible to accurately identify in which aspects the bionic blades show advantages over traditional blades, and in which areas there is still room for improvement.

[0070] Parameter adjustment: Based on the data analysis results, the parameters of the bionic leaf vein structure are optimized and adjusted; this includes adjusting the parameters of the main vein diameter, branching angle of the branch veins, diameter of the fine veins and the distance between the fine veins; for example, if the aerodynamic performance analysis shows that the lift coefficient is low, one can consider increasing the diameter of the main vein or adjusting the branching angle of the branch veins to improve the aerodynamic characteristics of the blade; this targeted parameter adjustment is intended to maximize the aerodynamic and structural performance of the bionic blade.

[0071] Composite material optimization: According to the structural optimization results, the plying order and thickness distribution of the composite material are adjusted to match the optimized vein structure and optimize the overall performance of the blade.

[0072] Specifically:

[0073] Adjustment of the laying sequence: Adjust the laying sequence of the composite materials according to the structural optimization results. For example, if the structural performance analysis shows that the stress in a specific area of ​​the blade is higher, consider adding more layers of high-strength composite materials in that area to improve the load-bearing capacity of the blade. This can not only significantly improve the load-bearing capacity of the blade, but also effectively control deformation and ensure the stability of the blade under extreme working conditions.

[0074] Thickness distribution optimization: At the same time, the thickness distribution of the composite material is adjusted according to the optimized vein structure; this includes increasing or decreasing the material thickness in certain areas to match the strength requirements of the vein structure; by optimizing the thickness distribution, we minimize the use of materials and reduce manufacturing costs.

[0075] Material selection: We are also considering replacing composite materials with better performance to further improve the overall performance of the blades. By introducing new high-performance composite materials, such as carbon fiber reinforced plastics or bio-based composite materials, the overall performance of the blades is further improved while reducing the impact on the environment.

[0076] Comprehensive evaluation and optimization

[0077] Overall performance evaluation: After each optimization iteration, the overall performance of the blade is comprehensively evaluated, including aerodynamic performance, structural performance, fatigue life, stiffness, ultimate strength and vibration instability. The design is further optimized based on the evaluation results to optimize the overall performance of the blade. The manufacturing process and cost factors of the blade are also considered. The feasibility, economy and environmental protection of the design are comprehensively evaluated to achieve the best balance between blade performance, cost and environment. This step ensures that the design optimization is not limited to the improvement of a single performance, but achieves comprehensive optimization of the comprehensive performance of the blade.

[0078] Design optimization: Based on the comprehensive evaluation results, the blade design is further optimized to achieve the best overall performance.

[0079] Through comprehensive evaluation, we strive to find the best balance between performance improvement and cost control, and achieve harmonious coexistence of blade performance, cost and environment.

[0080] Step 6: Verification and testing:

[0081] Prototype manufacturing: Based on the optimized design, a blade prototype is manufactured; this process not only verifies the effectiveness of the design optimization, but also accumulates valuable manufacturing experience for subsequent mass production.

[0082] Experimental verification: Experimental verification of the prototype blades, including aerodynamic performance tests, structural performance tests and fatigue life tests; these test data provide a solid experimental basis for further optimization of the design.

[0083] It also includes simulating blade performance under extreme weather conditions (such as strong winds, heavy rain, lightning, etc.), and evaluating the durability and reliability of blades in harsh environments such as sand, dust, and salt spray; these tests ensure that the blades can maintain stable and reliable performance under complex and changing environmental conditions.

[0084] Result analysis: Analyze the effectiveness of the optimized design based on the experimental results, and make further adjustments and optimizations as needed; make timely adjustments and optimizations for any problems or deficiencies found in the experiment to ensure that the final design is the best choice.

[0085] In summary, the present invention realizes the bionic optimization design of the fan blade structure by virtual partitioning and extracting the characteristic parameters of plant veins, which not only improves the aerodynamic performance and structural performance of the blade, but also significantly enhances the fatigue resistance of the blade, prolongs the service life, and further improves the overall performance of the blade through the application of composite materials and thickness design. In addition, the method also comprehensively optimizes the blade design through performance analysis and fatigue evaluation, ensures the stable operation of the blade in a complex environment, and reduces the probability of safety accidents.

Claims

1. A design method for a bionic vein structure of a large fan blade, characterized in that: The design method comprises the following steps: Step 1: Virtual partitioning of wind turbine blades and extraction of vein feature parameters; Virtual partitioning of blades: Divide the fan blades evenly into N partitions along the radial direction from the blade tip to the center of rotation, and each partition is approximately the total length L blade 1 / N of the partition boundary line along the blade rotation trajectory, ensuring that the mechanical behavior of each partition under wind load is relatively independent; Extraction of leaf vein characteristic parameters: Select plant leaf veins with excellent mechanical properties and aerodynamic characteristics, and extract key parameters of the leaf vein network, including: main vein diameter d main植物 、Branch angle θ branch植物 , veinlet spacing s fine植物 and veinlet diameter d fine植物 ;These parameters are used to guide the design of bionic leaf vein structure; Step 2: Design of bionic vein structure of each virtual partition of the leaf; Based on the parameters of plant veins, these parameters are proportionally amplified or adjusted according to the leaf size and performance requirements to obtain the bionic vein parameters suitable for wind turbine blades: the main vein diameter d min (x) = k d ·d main植物 f(x), branching angle θ branch =θ branch植物 , veinlet spacing s fine =k s ·s fine植物 , veinlet diameter d fine = k′ d ·d fine植物 , where k s and k d is the geometric magnification factor, k′ d is the adjustment coefficient of the veinlet diameter, f(x) is a decreasing function of the leaf length x, which is used to describe the variation of the main vein diameter along the leaf length; Main vein path planning: Design a continuous and smooth main vein path along the length of the blade. The main vein diameter d main (x) gradually decreases along the blade length x; the change relationship satisfies Where g(x) is a decreasing function; Design of branches and veins: Based on the main vein path, according to the branch angle θ branch Evenly arrange branches, the number of branches is n branch (i) is a constant in each partition, where i is the partition number; the veinlets start from the branch veins and are calculated according to the veinlet spacing s. fine and veinlet diameter d fine The regularity forms a network distribution, covering the entire leaf area; Step 3: Composite material application and thickness design; Composite material selection: choose a material with a tensile strength of σ t A composite material with an elastic modulus of E is used as the main material of the blade; Layer design: Based on the bionic leaf vein structure, the layering sequence and thickness distribution of the composite material are designed. The main part of the blade is laid alternately, and the thickness of each layer is t layer , total number of layers n layer Calculated and determined based on blade length and required strength; Step 4: Performance analysis and fatigue assessment; Aerodynamic performance analysis: Using CFD software to simulate wind speed v wind Aerodynamic performance of the bionic blade and calculation of lift coefficient C L , drag coefficient C D And the wind energy conversion efficiency η wind ; Structural performance analysis: The finite element analysis method is used to conduct static analysis on the bionic blade to evaluate the stress distribution and deformation of the bionic blade under extreme load; Fatigue analysis: Based on the service environment and load spectrum of the blade, fatigue analysis software is used to predict the fatigue life of the bionic blade. f ; Step 5: Optimize design; Parameter optimization: Based on performance analysis and fatigue assessment, the parameters of the bionic leaf vein structure are optimized and adjusted to further improve the aerodynamic and structural performance of the blade; Composite material optimization: According to the structural optimization results, the plying order and thickness distribution of the composite material are adjusted to match the optimized leaf vein structure and optimize the overall performance of the blade; Step 6: Verification and testing: Prototype manufacturing: According to the optimized design, the prototype of the blade is manufactured; Experimental verification: Experimental verification of the prototype blades, including aerodynamic performance tests, structural performance tests, and fatigue life tests; Result analysis: Analyze the effectiveness of the optimized design based on the experimental results and make further adjustments and optimizations.

2. The method for designing a bionic vein structure of a large wind turbine blade according to claim 1, characterized in that: The specific methods of optimizing the design in step five include: Parameter Optimization Data collection and analysis: First, collect all relevant data for performance analysis and fatigue assessment, including aerodynamic performance, structural performance, and fatigue life prediction results; Parameter adjustment: According to the data analysis results, the parameters of the bionic leaf vein structure are optimized and adjusted, including the parameters of the main vein diameter, branching angle of the branch veins, veinlet diameter and veinlet spacing; Composite material optimization Layer sequence adjustment: adjust the layer sequence of composite materials according to the structural optimization results; Thickness distribution optimization: At the same time, the thickness distribution of the composite material is adjusted according to the optimized leaf vein structure; Material selection: We also consider replacing composite materials with better performance to further improve the overall performance of the blades; Comprehensive evaluation and optimization Overall performance evaluation: After each optimization iteration, the overall performance of the blade is comprehensively evaluated, including aerodynamic performance, structural performance, and fatigue life; Design optimization: Based on the comprehensive evaluation results, the blade design is further optimized to achieve the best overall performance.

3. The method for designing a bionic vein structure of a large wind turbine blade according to claim 1, characterized in that: After each optimization iteration, a comprehensive evaluation should be conducted on the blade's stiffness, ultimate strength and vibration instability performance, and the design should be further optimized based on the evaluation results to optimize the overall performance of the blade.

4. The method for designing a bionic vein structure of a large wind turbine blade according to claim 1, characterized in that: After the performance analysis and fatigue assessment steps are completed, the results of performance analysis and fatigue analysis are used to compare the aerodynamic performance, structural performance, fatigue life and vibration characteristics of bionic blades and traditional blades; specifically, by quantitatively analyzing the parameters of bionic blades in improving wind energy conversion efficiency, reducing drag coefficient, enhancing structural stiffness, improving ultimate bearing capacity, extending fatigue life and controlling vibration instability, optimization ideas are provided for optimization design.

5. The method for designing a bionic vein structure of a large wind turbine blade according to claim 1, characterized in that: During the optimization design stage, the manufacturing process and cost factors of the blade should also be considered. By comprehensively evaluating the feasibility, economy and environmental protection of the design scheme, the optimal balance between blade performance, cost and environment can be achieved.

6. The method for designing a bionic vein structure of a large wind turbine blade according to claim 1, characterized in that: In step six, the experimental verification of the prototype blades should also include simulating the blade performance under extreme weather conditions, and evaluating the durability and reliability of the blades in harsh environments such as sand, dust and salt spray.

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