Ultra-high wind turbine tower design method and system

Abstract

This application relates to the field of data processing technology and discloses a design method and system for ultra-high wind turbine towers. The method includes: inputting the load conditions of the ultra-high wind turbine tower into a finite element analysis system; transforming the cylindrical cross-section into a polygonal shape using a geometric optimization algorithm to obtain parameters for a regular hexagonal polygonal cross-section; establishing a stress distribution model; segmenting and dividing the tower structure into sections to obtain standard tower sections and sector-shaped sections; optimizing the thickness of equal-thickness plates based on stress cloud diagram distribution to obtain a configuration of unequal-thickness irregular-shaped plates; replacing welded connections with bolted connections to obtain a bolted connection system; and inputting the tower structure composed of the connection system into a dynamic verification model for stiffness performance evaluation to obtain the design parameters for the ultra-high tower. This application solves the systemic technical problems faced by traditional tower technology in applications above 300 meters in height, such as transportation limitations, uneven material distribution, welding fatigue failure, and unclear dynamic response.

Description

Technical Field

[0001] This application relates to the field of data processing technology, and in particular to a design method and system for ultra-high wind turbine towers. Background Technology

[0002] Wind power generation is developing towards higher power output and ultra-high towers. Onshore wind turbine capacity has exceeded 25MW, and offshore wind power has reached the 50MW level. Correspondingly, tower height must exceed 300 meters to obtain higher altitude and more stable wind energy resources. Existing ultra-high wind turbine tower technologies mainly include three forms: concrete towers, conventional cylindrical steel towers, and truss towers. Concrete towers are constructed using precast segment casting on-site, conventional cylindrical steel towers use rolled plate welding technology to manufacture large-diameter steel cylinders, and truss towers use a spatial steel frame structure assembled on-site with bolts. These technologies have a certain engineering application basis for heights below 200 meters.

[0003] Existing technologies face systemic technical bottlenecks in ultra-high-altitude applications above 300 meters. Concrete towers have problems such as prefabricated segments weighing over 50 tons, making transportation difficult, difficulty in controlling on-site pouring quality, and safety hazards caused by concrete cracking. Conventional cylindrical steel towers are limited by the complexity of welding processes and transportation size constraints. When the tower diameter exceeds 4.5 meters, special transportation equipment and road modifications are required. The heat-affected zone of welding becomes the starting point of fatigue cracks, reducing structural reliability. Although truss towers have lightweight components that are easy to transport, their open structure leads to insufficient bending stiffness. When the height exceeds 250 meters, they are prone to vortex-induced vibration, which affects the stability of wind turbine operation.

[0004] Based on the analysis of the limitations of existing technologies in the application of ultra-high wind turbine towers, the technical problems exhibit a progressive relationship and mutual constraints. First, there are problems at the structural design level. Traditional cylindrical cross-sections require excessively large bottom diameters at a height of 300 meters to meet stiffness requirements, but this is not feasible due to transportation limitations, leading to a contradiction between structural geometric parameters and engineering constraints. Second, there are problems at the manufacturing process level. The design of equal-thickness plates causes a mismatch between material distribution and stress distribution, with insufficient material in high-stress areas and redundant material in low-stress areas. Third, there are problems at the connection technology level. Welded connections reveal the fundamental defect of insufficient fatigue life under the complex stress environment of ultra-high towers. Finally, there are problems at the overall performance verification level. There is a lack of systematic dynamic analysis methods for ultra-high towers above 300 meters, making it impossible to ensure the safety and reliability of the structure under extreme loads and long-term cyclic loads. Summary of the Invention

[0005] This application provides a design method and system for ultra-high wind turbine towers, which addresses systemic technical problems faced by traditional tower technology in applications at heights above 300 meters, such as transportation limitations, uneven material distribution, welding fatigue failure, and unclear dynamic response. Through integrated innovations such as segmented multi-faceted cross-section design, variable thickness optimization, all-bolted connection, and dynamic verification, the structural efficiency, manufacturing feasibility, and long-term reliability of ultra-high wind turbine towers are improved.

[0006] Firstly, this application provides a design method for ultra-high wind turbine towers, the design method comprising:

[0007] Step S1: Input the load conditions of the ultra-high wind turbine tower into the finite element analysis system, and use the geometric optimization algorithm to transform the traditional cylindrical section into a polygonal shape to obtain the polygonal section parameters of a regular hexagonal shape. The polygonal section parameters include the bottom diameter, the top diameter, and the taper ratio.

[0008] Step S2: Based on the parameters of the multi-faceted cross section, establish a stress distribution model, and perform segmentation and partitioning of the ultra-high tower structure to obtain multiple standard tower sections and multiple sector-shaped partition units;

[0009] Step S3: Based on the stress cloud diagram distribution of the fan-shaped segmented unit, perform variable thickness trapezoidal optimization on the equal thickness plate structure to obtain an unequal thickness irregular plate configuration from the bottom maximum thickness to the top minimum thickness.

[0010] Step S4: Based on the connection requirements of the unequal thickness irregular plate configuration, the welding connection method is completely replaced by bolts to obtain a high-strength bolt inter-plate connection system and a bolted plate inter-segment connection system.

[0011] Step S5: Input the tower structure composed of the inter-segment connection system and the inter-section connection system into the dynamic verification model, perform quantitative evaluation of the structural stiffness performance, and obtain the first-order bending mode frequency and the design parameters of the ultra-high tower.

[0012] Secondly, this application provides an ultra-high wind turbine tower design system, the ultra-high wind turbine tower design system comprising:

[0013] The input module is used to input the load conditions of the ultra-high wind turbine tower into the finite element analysis system. The traditional cylindrical section is transformed into a polygonal shape through a geometric optimization algorithm to obtain the polygonal section parameters of a regular hexagonal shape. The polygonal section parameters include the bottom diameter, the top diameter, and the taper ratio.

[0014] The splitting module is used to establish a stress distribution model based on the multi-faceted cross-section parameters, and to perform segmentation and piece-by-piece splitting of the ultra-high tower structure to obtain multiple standard tower segments and multiple fan-shaped piece-by-piece units.

[0015] The optimization module is used to perform variable thickness trapezoidal optimization processing on the equal thickness plate structure according to the stress cloud diagram distribution of the fan-shaped segment unit, so as to obtain an unequal thickness irregular plate configuration from the bottom maximum thickness to the top minimum thickness.

[0016] The replacement module is used to replace the welding connection method with bolts based on the connection requirements of the unequal thickness irregular plate configuration, so as to obtain a plate connection system with high strength bolts and a segment connection system with bolted connecting plates.

[0017] The evaluation module is used to input the tower structure composed of the inter-segment connection system and the inter-section connection system into the dynamic verification model, and to perform quantitative evaluation of the structural stiffness performance to obtain the first-order bending mode frequency and the design parameters of the ultra-high tower.

[0018] The technical solution provided in this application solves the fundamental contradiction between insufficient moment of inertia and transportation limitations in applications with traditional cylindrical sections at heights above 300 meters by inputting the load conditions of ultra-high wind turbine towers into a finite element analysis system and employing geometric optimization algorithms to transform the traditional cylindrical section into a polygonal shape. The determination of the parameters of the regular hexagonal polygonal section reduces the bottom diameter of the tower from 16 meters to 14 meters while maintaining the same load-bearing capacity, effectively overcoming the engineering bottleneck of the 4.5-meter width limitation for road transport. Based on the polygonal section parameters, a stress distribution model is established, and the ultra-high tower structure is segmented and partitioned, transforming the traditional large integral component into a modular design of multiple standard tower segments and multiple fan-shaped segmented units. This fundamentally solves the manufacturing and transportation problems of ultra-high towers, and the weight of the fan-shaped segmented units is controlled within 20 tons, ensuring the feasibility of standard road transport. Based on the stress cloud diagram distribution of the sector segment unit, the equal-thickness plate structure is optimized by a trapezoidal design with varying thickness. By configuring irregularly shaped plates with varying thicknesses from the bottom maximum thickness to the top minimum thickness, the material distribution and stress distribution are precisely matched. This eliminates the structural defects of insufficient material in high-stress areas and redundant material in low-stress areas in traditional equal-thickness designs, and significantly reduces material usage and structural weight.

[0019] Based on the connection requirements of unequal thickness irregular plate configurations, the welded connection method was completely replaced by bolted connections. The inter-plate connection system using high-strength bolts and the inter-segment connection system using bolted plates completely eliminated the adverse effects of the weld heat-affected zone and residual stress on the structural fatigue performance. The fatigue strength of the all-bolted connection is comparable to that of the base material and far exceeds that of the welded joint, fundamentally solving the fatigue failure problem of traditional welded connections under long-term cyclic loading. The tower structure composed of the inter-plate connection system and the inter-segment connection system was input into a dynamic verification model, and the structural stiffness performance was quantitatively evaluated. Systematic verification of the first-order bending mode frequency and ultra-high tower design parameters ensured the safety and reliability of the structure under various extreme conditions. The application of the dynamic verification model shifted the design of ultra-high towers from empirical design to scientific design based on precise calculations. Especially in the specific application field of ultra-high wind turbine towers, the geometric optimization algorithm achieves the optimal selection of cross-sectional shape through moment of inertia calculation, the variable thickness trapezoidal optimization algorithm achieves structural lightweighting through precise control of material distribution, and the eigenvalue solving algorithm ensures the reliability of vibration damping design through accurate calculation of natural frequency. The synergistic effect of these algorithms makes the ultra-high wind turbine tower design method of this application have outstanding technical advantages and engineering value in solving the engineering application problems of towers above 300 meters. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of one embodiment of the ultra-high wind turbine tower design method in this application;

[0022] Figure 2 This is a schematic diagram of the segmented structure of the regular hexagonal tower in the embodiments of this application;

[0023] Figure 3 This is a schematic diagram of the segmented structure of a single standard tower segment in an embodiment of this application. Detailed Implementation

[0024] This application provides a design method and system for ultra-high wind turbine towers. The terms "first," "second," "third," "fourth," etc. (if present) in the specification, claims, and accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments described herein can be implemented in a sequence other than that illustrated or described herein. Furthermore, the terms "comprising" or "having" and any variations thereof are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or device that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or devices.

[0025] For ease of understanding, the specific process of the embodiments of this application is described below. Please refer to [link / reference]. Figure 1 One embodiment of the ultra-high wind turbine tower design method in this application includes:

[0026] Step S1: Input the load conditions of the ultra-high wind turbine tower into the finite element analysis system, and use the geometric optimization algorithm to transform the traditional cylindrical section into a polygonal shape to obtain the polygonal section parameters of a regular hexagonal shape. The polygonal section parameters include the bottom diameter, the top diameter, and the taper ratio.

[0027] Step S2: Based on the parameters of the multi-faceted cross section, establish a stress distribution model, and perform segmentation and partitioning of the ultra-high tower structure to obtain multiple standard tower sections and multiple sector-shaped partition units;

[0028] Step S3: Based on the stress cloud diagram distribution of the sector segmented unit, perform variable thickness trapezoidal optimization on the equal thickness plate structure to obtain an unequal thickness irregular plate configuration from the maximum thickness at the bottom to the minimum thickness at the top.

[0029] Step S4: Based on the connection requirements of the unequal thickness irregular plate configuration, the welding connection method is completely replaced by bolts to obtain a high-strength bolt inter-plate connection system and a bolted plate inter-segment connection system.

[0030] Step S5: Input the tower structure composed of the inter-segment connection system and the inter-section connection system into the dynamic verification model, perform quantitative evaluation of the structural stiffness performance, and obtain the first-order bending mode frequency and the design parameters of the ultra-high tower.

[0031] It is understood that the executing entity of this application can be an ultra-high wind turbine tower design system, or it can be a terminal or a server; no specific limitation is made here. This application's embodiment uses a server as the executing entity for illustration.

[0032] Specifically, after inputting the tower base bending moment load of 800MN·m, shear load of 150MN, and axial force load of 200MN generated by a 25 MW wind turbine into a three-dimensional finite element model, static and dynamic simulation analysis generates a load distribution cloud map, which shows the spatial distribution characteristics of stress concentration areas. The geometric optimization algorithm, based on the principle of moment of inertia calculation, transforms the problem of insufficient moment of inertia in traditional cylindrical sections into a mathematical optimization problem of polygonal transformation. The algorithm first calculates the required bottom diameter of 16 meters for the cylindrical section at a height of 333 meters. Then, using the road transport constraint of 4.5 meters as a constraint, it calculates through equivalent diameter parameters that a regular hexagonal section can achieve the same stiffness level with a bottom diameter of 14 meters. The final output polygonal section parameters include a bottom diameter of 14 meters, a top diameter of 6 meters, and a taper ratio of 1:41.6. These parameters directly determine the geometric basis for subsequent segmented processing.

[0033] The stress distribution model based on the polygonal cross-section parameters converts the geometric parameters into a structural partitioning scheme. After receiving the polygonal cross-section parameters, the 3D finite element model generates three types of distribution envelope diagrams along the tower height during full-condition load simulation: the bending moment distribution envelope diagram reflects the load variation along the height, the shear force distribution envelope diagram shows the distribution characteristics of shear stress, and the axial force distribution envelope diagram characterizes the transmission path of axial pressure. The longitudinal segmentation analysis, based on the principle of stress continuity, divides the total height of 333 meters by 21 to obtain a single-segment height of 16.5 meters, ensuring a smooth transition of load transfer between segments. The circumferential segmentation calculation divides the regular hexagon into eight equal parts based on two side lengths. The geometric parameters of each sector segment are determined through trigonometric function calculations: the length is fixed at 16.5 meters, and the width is adjusted within the range of 2.5-3.8 meters according to the radius variation. A weight control algorithm ensures that the weight of a single segment does not exceed 20 tons. The shear stress minimization calculation determines the connection line position through finite element analysis and sets it at the midpoint of the polygonal edge, generating connection interface parameters for 168 sector segments.

[0034] The variable-thickness trapezoidal optimization process transforms the stress distribution of the sector-shaped unit into a material thickness configuration scheme. After applying actual working condition loads to each sector using a refined finite element model, stress analysis generates a stress contour map, which displays the spatial variation of stress values ​​within the range of 690MPa to 200MPa in the form of a color gradient. The stress gradient variation data is extracted using a numerical differential algorithm to identify the boundary positions of the high-stress region at the bottom and the low-stress region at the top. The material optimization mathematical model transforms the strength conditions into constraint equations, using the minimum material usage as the objective function, and solves for the optimal thickness distribution using a topology optimization algorithm. During the algorithm iteration, the thickness distribution parameters are gradually adjusted from the initial uniform thickness design to a trapezoidal distribution with a bottom thickness of 49mm and a top thickness of 20mm, with a slope transition parameter of 1:5 to ensure a smooth transition of stress concentration. The material usage minimization calculation applies the optimization results to 168 sector-shaped units, with the thickness configuration of each unit precisely matched according to its position and stress characteristics within the tower.

[0035] The all-bolted replacement treatment solved the fatigue problem of welded connections. After the fatigue analysis model was established, the stress amplitude at the weld root was calculated using the nominal stress method, and the stress concentration factor at the crack initiation location was analyzed using the local stress method. A 2×10^6 cycle load corresponds to a 25-year design life, and fatigue load parameters were extracted from the actual load spectrum using the rainflow counting method. A comparison between the fatigue strength of the welded joint (210 MPa) and the fatigue strength of the Q690D base material (355 MPa) shows that the weld is a weak point in the structure. The bolted design treatment improved the inter-plate connection interface to Sa2.5 level through sandblasting, achieving an anti-slip coefficient of over 0.45. The bearing capacity of the M30 specification 10.9 grade high-strength bolts was determined to be 280 kN through material testing, and the connection configuration of 2048 bolts was arranged in double rows with a 150 mm spacing. In the external connecting plate bolt design, the 30 mm thick connecting plate was quickly positioned using pre-embedded bolt holes, and 256 bolts were applied to each inter-section interface. The fatigue verification model verified the bolted connection under 2×10^6 cycles of loading through cyclic loading tests. There was no loosening after the second cycle, and the safety factor reached more than 1.8.

[0036] The dynamic verification process converts the mechanical properties of the connected system into dynamic response parameters of the overall structure. The three-dimensional finite element dynamic model integrates all geometric parameters, material properties, and connection characteristics from the previous four steps, forming a complete description of the mass and stiffness matrices. Modal analysis uses a subspace iterative method to solve the generalized eigenvalue problem, extracting the first 10 natural frequencies and corresponding mode shapes of the tower. The first-order bending mode frequency is calculated using the ratio of structural stiffness to mass distribution. The vibration avoidance verification process compares the calculation results with the 0.25Hz critical frequency to ensure avoidance of the wind turbine's 1P frequency resonance range. Displacement response under extreme loads is calculated using nonlinear static analysis. The tower top displacement under a 50-year return period wind load of 55m / s is calculated to be 1.8 meters by gradually applying wind pressure load using the load increment method. The structural dynamic response under a seismic load of 0.4g is calculated using time history analysis. The structural reliability index of 3.7 is calculated using the first-order second-moment method, comprehensively considering the uncertainties of material strength, geometric parameters, and loads.

[0037] In one specific embodiment, step S1 includes:

[0038] The bending moment load, shear load, and axial force load at the bottom of the 25 MW wind turbine were input into a three-dimensional finite element model. Through static and dynamic simulation analysis, the load distribution cloud map and stress concentration area identification results under extreme working conditions were obtained.

[0039] Based on the load distribution cloud map, a geometric improvement analysis is performed on the problem of insufficient moment of inertia of traditional cylindrical cross sections. By calculating the moment of inertia, the traditional cylindrical cross sections are transformed into polygonal sections to obtain the equivalent diameter and stiffness parameters of a regular hexagonal cross section.

[0040] The bottom diameter requirement of the tower is optimized based on the stiffness parameters. The road transport constraints are input into the geometric optimization algorithm to obtain the geometric parameters of the conical tower.

[0041] The bending moment of inertia and torsional moment of inertia were verified and calculated based on the geometric parameters of the conical tower. By comparing the performance with that of a cylindrical section of the same diameter, the parameters of the polygonal section composed of the bottom diameter, top diameter and taper ratio were obtained.

[0042] Specifically, the three main load data generated during the operation of the 25 MW wind turbine were imported into a three-dimensional finite element model. The tower base bending moment load reflects the overturning moment generated by the wind turbine on the root of the tower under horizontal wind force; the shear load represents the shear force generated by the weight of the wind turbine and wind pressure on the cross-section of the tower; and the axial force load represents the pressure transmitted axially from the weight of the wind turbine nacelle, hub, blades, and other upper structures to the foundation through the tower. Static and dynamic simulation analysis employed the finite element numerical calculation method, discretizing the tower structure into numerous small elements. Each element was connected by nodes to form an overall stiffness matrix. Static analysis calculated the displacement and stress of each node by solving the equilibrium equations. Dynamic analysis considered the influence of inertial forces and damping forces on the basis of static analysis, and calculated the structural response under dynamic loads using the time-domain integration method. The load distribution cloud map visually displays the stress distribution in various parts of the tower using color gradients. Red areas indicate high stress concentration locations, and blue areas indicate low stress distribution locations. The stress concentration area identification results automatically marked dangerous areas exceeding the allowable stress of the material by setting a stress threshold. The geometric improvement analysis, based on the stress distribution characteristics displayed by the load distribution cloud map, identifies the problem of excessive stress in the bottom region and excess stress in the middle and upper parts of the traditional cylindrical section when subjected to bending moment load. The moment of inertia calculation adopts the section geometric property analysis method. The moment of inertia of the cylindrical section is proportional to the fourth power of the diameter. When the tower height reaches 333 meters, the required diameter at the bottom exceeds the transportation limit. The polygonal transformation process converts the circular section into a regular hexagonal section. While maintaining the same circumscribed circle diameter, the internal material distribution is more optimized. The equivalent diameter parameter is determined by the equivalent moment of inertia calculation. The stiffness parameters include two key indicators: bending stiffness and torsional stiffness. Compared with the circle, the regular hexagon has a higher section modulus with the same material usage. The optimization calculation process uses stiffness parameters as the objective function and the tower bottom diameter requirement as the design variable. Highway transportation restrictions stipulate that the width of a single component must not exceed 4.5 meters. The geometric optimization algorithm employs a sequential quadratic programming method, iteratively calculating to find the optimal combination of geometric parameters that meets both strength requirements and transportation constraints. The geometric parameters of the conical tower include a bottom diameter of 14 meters, a top diameter of 6 meters, and the corresponding taper variation. The verification calculation process re-inputs the optimized conical tower geometric parameters into the finite element model to calculate the bending and torsional moments of inertia of the regular hexagonal cross-section. The bending moment of inertia determines the tower's bending deformation capacity under horizontal loads, while the torsional moment of inertia determines its torsional deformation capacity under torsional loads. Performance comparison analysis uses a cylindrical cross-section model with the same outer diameter to calculate the ratio of the moments of inertia between the two cross-section forms, verifying the advantages of the polygonal cross-section in terms of structural efficiency. The final output polygonal cross-section parameters include the optimized and verified bottom diameter, top diameter, and taper ratio—three core geometric parameters that directly determine the tower's load-bearing capacity and material distribution.

[0043] In one specific embodiment, step S2 includes:

[0044] By inputting the parameters of the multi-faceted section into a three-dimensional finite element model, stress analysis was performed on the 333-meter ultra-high tower structure through full-condition load simulation, resulting in the bending moment distribution envelope, shear force distribution envelope, and axial force distribution envelope along the tower height direction.

[0045] Based on the bending moment distribution envelope diagram, shear force distribution envelope diagram, and axial force distribution envelope diagram, the tower structure is longitudinally segmented for analysis. According to the principle of stress continuity, the 333-meter tower is divided into 21 standard segments with a height of 16.5 meters, and the segment configuration parameters of multiple standard tower segments are obtained.

[0046] Based on the segment configuration parameters, each standard tower segment is circumferentially segmented and calculated. The regular hexagonal cross section is divided into 8 sector segments with 2 side lengths as units, resulting in multiple sector segment units with a length of 16.5 meters, a width of 2.5-3.8 meters, and a weight of less than 20 tons.

[0047] Based on the geometric parameters of multiple sector-shaped segments, the connection positions between segments are optimized and selected. By minimizing shear stress, the connection lines are set at the midpoints of the multi-sided edges, resulting in the connection interface parameters and load transfer path configurations for 168 sector-shaped segments.

[0048] Specifically, the geometric parameters such as the bottom diameter, top diameter, and taper ratio determined in the previous steps are imported into a three-dimensional finite element analysis model to establish a complete tower geometry model containing the characteristics of a regular hexagonal cross-section. In the model, each cross-section varies linearly along the height direction according to the taper ratio to ensure geometric continuity and structural integrity. Full-condition load simulation covers all load conditions encountered during wind turbine operation, including rated conditions, extreme wind speed conditions, start-up and shutdown conditions, yaw conditions, and other operating states. Each condition corresponds to different load magnitudes and directions. The load effects of all conditions are superimposed to form an envelope load. Stress analysis employs the finite element numerical calculation method, discretizing the 333-meter tower structure into tens of thousands of elements. The displacement and stress of each node are calculated by solving a large system of linear equations. The bending moment distribution envelope diagram records the maximum bending moment value borne by each cross-section along the height direction of the tower; the shear force distribution envelope diagram records the maximum shear force value borne by each cross-section; and the axial force distribution envelope diagram records the maximum axial force value borne by each cross-section. These three types of envelope diagrams together constitute a complete description of the internal force distribution of the tower. The longitudinal segmentation analysis is based on the internal force variation law shown by the envelope diagram to determine the segmentation scheme. The bending moment distribution envelope diagram shows that the bending moment is the largest at the bottom of the tower and gradually decreases upward. The shear force distribution envelope diagram shows that the shear force changes relatively gently along the height. The axial force distribution envelope diagram shows that the axial force gradually accumulates downward from the top of the unit weight. The principle of stress continuity requires that the stress transfer between adjacent segments be smooth and avoid stress abrupt changes. Dividing the total height of 333 meters by the number of segments of 21 yields a standard height of 16.5 meters for a single segment. The segment configuration parameters include key information such as the start and end heights of each segment, the variation law of cross-sectional dimensions, and load distribution characteristics. The division of multiple standard tower segments satisfies both structural mechanics requirements and engineering constraints of manufacturing and transportation.

[0049] The circumferential segmentation calculation process divides the regular hexagonal cross-section of each standard tower segment into equal angles. Based on the principle of dividing in units of two side lengths, the hexagon is decomposed into eight sector segments. Each sector segment contains two adjacent polygonal edges and an arc-shaped part connecting these two edges. The central angle of the sector segment is 45 degrees to ensure geometric symmetry. The length parameter is fixed at 16.5 meters, corresponding to the height of a single tower segment. The width parameter varies according to the diameter of the tower cross-section along the height. The bottom width is 3.8 meters, corresponding to a circumferential segment with a bottom diameter of 14 meters, and the top width is 2.5 meters, corresponding to a circumferential segment with a top diameter of 6 meters. The weight control algorithm calculates the weight of each sector segment by multiplying the material density by the volume. The volume calculation takes into account the conical changes and the geometric characteristics of the polygonal edges. The weight limit is 20 tons, corresponding to the load capacity of standard road transport. After the geometric parameters of multiple sector segment units are determined, modular manufacturing and transportation units are formed. The optimization of inter-segment connection positions addresses the connection issues between sector segments. Shear stress minimization calculations utilize finite element analysis to determine the shear stress distribution at the boundaries of sector segments. The shear stress reaches its minimum at the midpoint of the multi-edged edges. Setting the connection line at the midpoint minimizes stress concentration at the connection points. The 168 sector segments are derived by multiplying 21 segments by 8 segments. Connection interface parameters include geometric features such as the position, length, and tilt angle of the connection line. The load transfer path configuration describes the mechanical path of load transfer from one sector segment to adjacent sector segments through the connection interface, ensuring the continuity of load transfer and structural integrity of the overall structure.

[0050] Figure 2 This is a schematic diagram of the segmented structure of the regular hexagonal tower in an embodiment of this application. Figure 2 As shown, the circumferential section of the regular hexagonal tower is divided into circumferential segments based on two side lengths, dividing the complete hexagonal section into eight sector segments. Each sector segment is distinguished by a different color for easy identification. The sector segments are connected by bolts through connection interfaces. The green lines in the figure indicate that the connection lines between the segments are located at the midpoint of the polygonal edges to minimize shear stress. This segmentation design ensures that the size and weight of each sector segment meet the requirements of standard highway transportation, while maintaining the structural integrity of the tower section and the continuity of load transfer, laying the foundation for the modular manufacturing and on-site assembly of ultra-high wind turbine towers.

[0051] Figure 3 This is a schematic diagram of the segmented structure of a single standard tower section in an embodiment of this application. For example... Figure 3As shown, a single standard tower section is 16.5 meters high. The regular hexagonal cross-section is divided into 8 sector-shaped segments along the circumference. Each sector segment is distinguished by a different color. The connection interface between the sector segments is indicated by green lines and is located at the midpoint of the polygonal edges to achieve the best load transfer effect. Flange connection structures are provided at the top and bottom of the tower section for inter-segment connection. The bottom flange has a larger diameter to withstand greater loads, while the top flange has a relatively smaller diameter to reflect the tapered design. This structural design not only ensures the structural integrity of the single tower section, but also meets the engineering requirements for transportation and on-site assembly through the segmented design, providing a feasible technical solution for the modular construction of 333-meter ultra-high wind turbine towers.

[0052] In one specific embodiment, step S3 includes:

[0053] Multiple sector-shaped segmented units are input into a refined finite element model. Stress analysis is performed on each sector-shaped segment by applying actual working condition loads to obtain the stress cloud distribution and stress gradient change data of each sector-shaped segment.

[0054] Based on the stress cloud map distribution, the material distribution unevenness problem of the plate structure with uniform thickness is identified and analyzed. The thickness optimization range is determined by the gradient change of stress value from 690MPa to 200MPa, and the stress distribution characteristics of the bottom high stress region and the top low stress region are obtained.

[0055] A material optimization mathematical model was established based on the stress distribution characteristics. The strength condition was used as a constraint condition to perform topology optimization calculation on the thickness distribution, and the variable thickness distribution parameters from the bottom thickness of 49 mm to the top thickness of 20 mm and the 1:5 slope transition parameters were obtained.

[0056] The thickness configuration of each sector segment was verified based on the variable thickness distribution parameters and slope transition parameters. The optimized thickness parameters were applied to 168 sector segments by minimizing material usage to obtain the configuration of unequal thickness irregular plates.

[0057] Specifically, the geometric parameters and material properties of the 168 generated sector segments are imported into a refined finite element model. This model has a higher mesh density and computational accuracy compared to the overall tower model, and can accurately capture the stress distribution details within each individual sector segment. For actual operating condition load application, based on the position and orientation of each sector segment within the overall tower, the corresponding load components are precisely applied to the sector segment model. The loads include various components such as the normal force from wind pressure, the axial force from gravity, and the distributed load from bending moment. Stress analysis is performed by calculating the stress field distribution within each sector segment using a finite element solver. The stress cloud map distribution displays the spatial variation of stress values ​​in the form of a color gradient, with red areas representing high stress concentration areas and blue areas representing low stress distribution areas. The stress gradient variation data is extracted from the stress field using numerical differentiation methods, quantifying the stress variation along the height direction of the sector segment.

[0058] The analysis and processing are based on the color distribution characteristics displayed by the stress cloud map to identify the mismatch between material distribution and stress distribution in equal-thickness plate structures. Equal-thickness plate structures refer to the traditional design method of using the same thickness for fan-shaped sections along the height direction. The problem of uneven material distribution is manifested as insufficient material in high-stress areas and excessive material in low-stress areas. The gradient change of stress value from 690MPa to 200MPa is calculated by linear interpolation to determine the continuous change law of stress from the bottom maximum value to the top minimum value. The thickness optimization range is determined based on the stress gradient to determine the space range for adjusting the material thickness. The high-stress area at the bottom corresponds to the part where the stress value is close to the yield strength of Q690D steel of 690MPa, and the material thickness needs to be increased to ensure a safety margin. The low-stress area at the top corresponds to the part where the stress value is only 200MPa, and the material utilization rate is low, so there is room for thinning optimization. The stress distribution characteristics are extracted by statistical analysis methods to extract key parameters such as the mean, variance, and extreme values ​​of the stress distribution. The material optimization mathematical model establishes and processes the stress distribution characteristics into an objective function and constraints for a mathematical optimization problem. The objective function aims to minimize material usage. The total volume and weight of the sector segments are calculated through integration. Constraints include strength requirements that the stress in each part does not exceed the allowable stress of the material, and geometric requirements that the thickness variation should maintain continuity to avoid abrupt stress changes. Topology optimization calculations use the density method to optimize material distribution. This method uses material density as a design variable and finds the optimal material distribution scheme through iterative calculations. The optimization algorithm starts with an initial uniform thickness distribution and gradually adjusts the material thickness of each part until the strength constraints are met and the material usage is minimized. The variable thickness distribution parameters, from 49mm at the bottom to 20mm at the top, are determined through optimization iterations. 49mm corresponds to the minimum thickness in the high-stress area at the bottom to ensure load-bearing safety, and 20mm corresponds to the minimum thickness in the low-stress area at the top to meet stiffness requirements. A 1:5 slope transition parameter controls the smoothness of the thickness variation. Too gentle a slope will increase material usage, while too steep a slope will cause stress concentration.

[0059] The thickness configuration verification process involves re-inputting the optimized variable thickness distribution parameters into the finite element model for stress checking to verify whether the stress in each part meets the strength requirements. The material usage minimization calculation uses the volume integration method to calculate the material usage of each optimized sector segment and compares it with the material usage of the equal thickness design. Based on their different positions and stress characteristics in the tower, the 168 sector segments are configured with corresponding thickness parameters. The bottom sector segment uses a thickness configuration of nearly 49mm to cope with high stress loads, the middle sector segment uses a linear transition thickness configuration to balance strength and usage, and the top sector segment uses a thickness configuration of nearly 20mm to meet basic load-bearing requirements. The unequal thickness irregular plate configuration is formed by integrating the thickness parameters of all sector segments to form a material configuration scheme.

[0060] In one specific embodiment, step S4 includes:

[0061] A fatigue analysis model was established based on the configuration of irregularly shaped plates with unequal thickness. The fatigue life of the welded connection was calculated using a combination of the nominal stress method and the local stress method, yielding a 2× Results of weld fatigue failure risk assessment under secondary cyclic loading and comparative data of fatigue strength of bolted connections;

[0062] Based on the fatigue failure risk assessment results, the inter-piece connection method was designed to be bolted. The connection interface was sandblasted to achieve Sa2.5 level to ensure the anti-slip coefficient ≥0.45. The inter-piece connection parameters of M30 specification 10.9 grade high strength bolts and the connection configuration of 2048 bolts were obtained.

[0063] Based on the connection configuration, the inter-segment connection structure is designed with external connecting plate bolts. By pre-embedding high-strength bolt holes, 256 M30 bolts are applied to each interface for rapid positioning, resulting in an inter-segment connection system with a 30mm thick connecting plate and a double-row arrangement parameter with a bolt spacing of 150mm.

[0064] The inter-segment connection configuration and inter-section connection system were input into the fatigue verification model, and 10.9 grade bolts were used in 2× The non-loosening verification process under multiple cyclic loads yielded a high-strength bolt inter-plate connection system with a safety factor ≥1.8 and an inter-segment connection system of bolted connecting plates.

[0065] Specifically, the thickness distribution parameters and material properties of each sector segment are imported into the fatigue calculation model. This fatigue analysis model is specifically designed to evaluate the long-term durability of the structure under cyclic loading. The nominal stress method calculates the nominal stress value by dividing the load at the connection by the net cross-sectional area. This method is suitable for assessing fatigue performance far from geometrical discontinuities. The local stress method, on the other hand, is specifically designed for stress concentration areas such as welds, holes, and geometrical abrupt changes. Finite element analysis is used to calculate the local stress peak and stress concentration factor. Combining these two methods provides a comprehensive assessment of the fatigue risk at the connection. The fatigue life calculation for welded connections uses the SN curve method. The SN curve describes the relationship between stress amplitude and the number of fatigue life cycles. Due to the complex microstructure of weld metal, heat-affected zone, and fusion line, the fatigue strength of welded joints is significantly lower than that of the base material. A 2×10⁶ cyclic load corresponds to a 25-year design life for wind turbines. The weld fatigue failure risk assessment results are obtained by comparing the actual stress amplitude with the fatigue strength limit. Comparative data on the fatigue strength of bolted connections are obtained by analyzing the differences in fatigue performance between bolt materials and welded joints.

[0066] The bolted design addresses fatigue weakness in welded connections identified through fatigue failure risk assessment. Traditional welded connections are replaced with mechanical bolted connections. Inter-segment connections refer to the method of connecting adjacent sector segments. The bolted design uses high-strength bolts to avoid the heat-affected zone and residual stress generated by welding. Sandblasting of the connection interface uses compressed air to drive abrasive particles for surface treatment. Sa2.5 is the surface cleanliness level specified in international standards, indicating that over 95% of the surface area achieves a clean metallic luster. The anti-slip coefficient is the coefficient of friction of the friction surfaces in a bolted connection; a higher value indicates stronger anti-slip capability. An anti-slip coefficient of 0.45 ensures that the bolted connection does not slip under design loads. M30 indicates that the nominal diameter of the bolt is 30 mm, and grade 10.9 indicates the strength grade of the bolt, corresponding to a yield strength of 900 MPa and a tensile strength of 1000 MPa. The inter-plate connection parameters include technical parameters such as bolt specifications, quantity, spacing, and arrangement. The connection configuration of 2048 bolts is determined through load-bearing capacity calculations. Each bolt can bear 280 kN, and the total load-bearing capacity meets the load transfer requirements between the plates.

[0067] The external connecting plate bolt design addresses the inter-segment connection issue. Inter-segment connection refers to the connection method between adjacent standard tower segments. The external connecting plate is a connecting component installed on the outer surface of the tower, connecting the upper and lower tower segments into a whole using bolts. Pre-embedded high-strength bolt holes are precision holes pre-machined during the connecting plate manufacturing process, with hole diameter tolerance controlled within 0.1 mm. Rapid positioning is achieved through the guiding effect of the pre-embedded holes, ensuring accurate alignment of the upper and lower tower segments. 256 M30 bolts are used in the calculations for each interface based on the load components such as bending moment, shear force, and axial force transmitted between segments. The 30mm thick connecting plate is determined through strength calculations. The connecting plate needs sufficient thickness to withstand the concentrated load transmitted by the bolt group and avoid local buckling. The inter-segment connection system includes a complete set of connecting components such as connecting plates, bolts, washers, and nuts. The bolt spacing of 150mm is determined through bolt group effect analysis; too small a spacing will cause mutual interference, while too large a spacing will lead to local bending of the connecting plate. The double-row arrangement parameter refers to the geometric configuration of the bolts arranged in two rows, which can better withstand bending moment loads.

[0068] The fatigue verification process inputs all parameters of the inter-plate connection configuration and the inter-segment connection system into a specialized fatigue test model. This model verifies the fatigue performance of the bolted connection through actual cyclic loading tests. The non-loosening verification of 10.9 grade bolts under 2×10⁶ cyclic loads adopts the standard fatigue test method. During the test, the change in bolt preload is monitored. No loosening indicates that the bolt preload remains within the design range without significant attenuation. The safety factor of 1.8 is the safety margin in fatigue design, calculated by dividing the material fatigue strength by the actual stress amplitude. A safety factor greater than 1.8 ensures that the connection will not experience fatigue failure within the design life. After fatigue verification, the inter-plate connection system of high-strength bolts and the inter-segment connection system of bolted connecting plates form a complete all-bolted connection scheme.

[0069] In one specific embodiment, a fatigue analysis model is established based on the configuration of unequal-thickness irregular plates. The fatigue life calculation of the welded connection method is performed using a combination of the nominal stress method and the local stress method, including:

[0070] Using a preset fatigue load spectrum as input, the equivalent number of cycles is used to calculate 2× the design life of 25 years. The fatigue load parameters and stress cycle range data of the welded joint and bolted connection were obtained by repeated cyclic loading.

[0071] The stress concentration factor of the heat-affected zone of the welded joint was analyzed based on fatigue load parameters. The stress amplitude at the root of the weld was calculated by the nominal stress method and the crack initiation position was analyzed by the local stress method. The weld failure risk data with a fatigue strength of 210 MPa and a stress concentration factor of 2.8 were obtained.

[0072] Based on the weld failure risk data, fatigue strength comparison calculations were performed on Q690D base material. The difference between the base material fatigue strength of 355MPa and the weld joint fatigue strength of 210MPa was analyzed by SN curve analysis to obtain the comparison results.

[0073] Based on the comparative results, a fatigue analysis model for bolted connections was established. Through analysis of the material properties of high-strength bolts and the mechanism of preload, a 2× The results of the risk assessment of weld fatigue failure under secondary cyclic loading and the comparison data of fatigue strength of bolted connections.

[0074] Specifically, the various load conditions experienced by the wind turbine during actual operation are transformed into standardized fatigue load data. The fatigue load spectrum includes the load amplitude and frequency distribution at different wind speed levels, recording all load cycles experienced by the tower during 25 years of operation. The equivalent cycle count calculation employs the rainflow counting method to statistically analyze the complex random load history. The rainflow counting method decomposes the irregular load-time history into a series of complete stress cycles, each containing a maximum value, minimum value, and cycle amplitude. By statistically analyzing the cycle count corresponding to each stress amplitude, the 25-year complex load history is equivalent to 2 × 10⁻⁶ cycles. The standard cyclic load, fatigue load parameters include key data such as stress amplitude range, average stress level, and cycle frequency. The stress cycle range data describes the stress variation amplitude of welded joints and bolted connections under cyclic load. Welded joints have a larger stress cycle range due to geometric discontinuities and material inhomogeneities, while bolted connections have a relatively smaller stress cycle range due to the preload.

[0075] Stress concentration factor analysis specifically targets the heat-affected zone (HAZ) of welded joints, calculating the micro-stress distribution. The HAZ is a region of metal microstructure change caused by high temperatures during welding, exhibiting significant differences in material properties compared to the base metal. Its microstructure includes different characteristic regions such as coarse-grained, fine-grained, and overheated zones, each with varying hardness, toughness, and fatigue performance. The nominal stress method calculates the stress amplitude at the weld root using a simplified section method, treating the weld as an equivalent uniform section. The average stress level is calculated by dividing the load by the net cross-sectional area. However, this method cannot reflect the stress concentration effect caused by the weld geometry. The local stress method analyzes crack initiation locations by calculating the stress peaks at the weld root and weld toe using a refined finite element model. These locations become fatigue crack initiation points due to geometrical abrupt changes and residual stress. The weld joint fatigue strength of 210 MPa is a material constant determined through standard fatigue testing. The stress concentration factor of 2.8 represents the ratio of the local stress peak to the nominal stress. Weld failure risk data is calculated by comparing the actual stress amplitude with the fatigue strength limit to determine the cumulative damage.

[0076] The fatigue strength comparison calculation quantitatively compared the fatigue performance of Q690D base material with that of welded joints. Q690D steel, as a high-strength structural steel, has excellent fatigue performance, with a fatigue strength of 355MPa, which is much higher than that of welded joints (210MPa). The SN curve analysis used a double logarithmic coordinate system to plot the relationship between stress amplitude and fatigue life. The flatter slope of the SN curve for the base material indicates that its fatigue performance is less affected by stress amplitude, while the steeper slope of the SN curve for the welded joint indicates that its fatigue performance is sensitive to stress amplitude. The difference analysis showed that under the same stress amplitude, the fatigue life of the base material is several times that of the welded joint. The comparison results quantified the disadvantage of welded connections in terms of fatigue performance and provided a theoretical basis for the technical solution of bolted connections replacing welded connections.

[0077] A fatigue analysis model for bolted connections was established to address the fatigue disadvantages of welded connections as shown in the comparative results. Mechanical connections were adopted to avoid the adverse effects of welding. The material properties of high-strength bolts were analyzed, including key parameters such as the chemical composition, heat treatment process, and mechanical properties of the bolt steel. Grade 10.9 bolts were made of alloy steel and achieved high strength and good toughness through tempering heat treatment. The mechanism of preload action was analyzed to study the influence of bolt preload on fatigue performance. Appropriate preload can reduce the stress variation of bolts under cyclic loading; excessive preload leads to excessive static stress, while insufficient preload leads to loosening of the connection. The optimal preload was determined through theoretical calculation and experimental verification. The weld fatigue failure risk assessment results showed that welded connections at 2× After multiple cycles, the failure probability exceeds 10%. Comparative data on the fatigue strength of bolted connections show that the fatigue strength of grade 10.9 bolts reaches 355MPa, which is comparable to that of the base material, verifying the advantages of bolted connections in terms of fatigue performance.

[0078] In one specific embodiment, step S5 includes:

[0079] The connection characteristics of the inter-segment connection system and the inter-section connection system are input into the three-dimensional finite element dynamic model. Through the complete tower modeling process that includes all geometric parameters, material properties and connection characteristics, the dynamic analysis model and structural mass matrix of the 333-meter complete tower are obtained.

[0080] Modal analysis calculations were performed on the tower structure based on the dynamic analysis model. The first 10 natural frequencies and corresponding mode shapes of the tower were extracted by the eigenvalue solving algorithm, and the frequency parameters and mode shape characteristic data of the first bending mode, the second bending mode and the torsional mode were obtained.

[0081] Based on the frequency parameters, vibration avoidance verification was carried out on the frequency resonance risk of the 1P wind turbine. By comparing the first-order bending mode frequency with the critical frequency of 0.25Hz, the resonance avoidance condition of the first-order frequency being greater than or equal to 0.25Hz was ensured, and the first-order bending mode frequency and dynamic characteristics verification results that meet the resonance avoidance requirements were obtained.

[0082] Based on the dynamic characteristic verification results, the displacement response under extreme loads was quantitatively calculated. Through displacement calculations under 50-year return period wind load of 55m / s and seismic load of 0.4g, the design parameters of the ultra-high tower with a tower top displacement of 1.8m (less than the allowable value of 3.5m) and a structural reliability index of 3.7 were obtained.

[0083] Specifically, all mechanical parameters of the determined inter-segment and inter-section connection systems are imported into a three-dimensional finite element dynamic model. Connection characteristics include key parameters such as bolt stiffness, connection stiffness, and damping characteristics. The contribution of the 2048 M30 bolts in the inter-segment connection system to the overall structural stiffness is characterized by equivalent spring stiffness. The connection characteristics of the 256 bolts and 30mm connecting plate in the inter-section connection system are described by contact stiffness and bending stiffness parameters. The complete tower modeling process integrates all geometric parameters, material properties, and connection characteristics into a unified numerical model. Geometric parameters include the dimensional variation of the regular hexagonal cross-section, the height distribution of the 21 standard tower segments, and the spatial configuration of the 168 sector segments. Material properties include physical constants such as the elastic modulus, Poisson's ratio, and density of Q690D steel. Connection characteristic parameters are integrated into the overall structural model in the form of a stiffness matrix. Compared with the static model, the dynamic analysis model adds consideration of inertial forces and damping forces. The structural mass matrix is ​​formed by assembling the mass matrices of all elements, and this matrix describes the mass distribution and inertial characteristics of each part of the structure.

[0084] Modal analysis calculations are based on dynamic analysis models to solve for the inherent vibration characteristics of structures. Modal analysis is a fundamental analytical method in structural dynamics. By solving generalized eigenvalue problems, the natural frequencies and mode shapes of the structure are obtained. The eigenvalue solving algorithm uses the subspace iteration method or the Lanczos method to handle the eigenvalue problems of large sparse matrices. The algorithm first selects an initial vector space and gradually approximates the true eigenvectors through iterative calculations. The first 10 natural frequencies extracted cover the main vibration modes of the structure. The first bending mode corresponds to the foundation bending vibration of the structure in the horizontal direction, and the mode shape is the bending deformation mode of the tower along the height direction. The second bending mode corresponds to higher-order bending vibration modes, and the mode shape deformation is more complex. The torsional mode corresponds to the torsional vibration of the tower about the longitudinal axis. The frequency parameters and mode shape characteristic data are accurately determined through numerical calculations. The frequency value of each mode reflects the natural period of the vibration mode, and the mode shape data describes the relative displacement amplitude and phase relationship of each point of the structure.

[0085] Vibration damping verification treatment addresses the resonance problem between the wind turbine tower and the turbine impeller based on frequency parameters. The 1P frequency of the wind turbine refers to the frequency at which the impeller generates an excitation once per revolution. For a 25 MW wind turbine at its rated speed, the 1P frequency is typically in the range of 0.15-0.2Hz. Resonance risk refers to the severe vibration that can occur when the tower's natural frequency is close to the excitation frequency, leading to fatigue damage. The 0.25Hz critical frequency is a commonly used resonance avoidance design criterion in the wind power industry, requiring the tower's first-order bending mode frequency to be higher than this critical value to ensure sufficient separation from the 1P frequency. Comparative calculations compare the calculated first-order bending mode frequency with 0.25Hz to ensure that the resonance avoidance condition of a first-order frequency greater than or equal to 0.25Hz is met. The value of the first-order bending mode frequency directly relates to the tower's vibration resistance performance. The dynamic characteristic verification results include a comprehensive evaluation of multiple indicators such as frequency margin, mode shape rationality, and modal participation factor.

[0086] Extreme load displacement response calculations were performed to verify the structural safety of the tower under severe conditions. The 50-year return period wind load refers to the extreme wind speed condition with a mean return period of 50 years, corresponding to the ultimate load condition of a wind speed of 55 m / s. The seismic load condition of 0.4g corresponds to an earthquake excitation with a peak ground acceleration of 0.4 times the gravitational acceleration. The displacement calculation adopted a geometric nonlinear analysis method to consider the influence of large deformation on the structural stiffness. The calculation process gradually applied the extreme load through incremental loading until the design value was reached. The tower top displacement of 1.8m was obtained by calculating the displacement response of the top node of the structure. The allowable value of 3.5m is a displacement limit determined based on structural safety and wind turbine operation requirements. The structural reliability index of 3.7 is a reliability measure of the probability of structural failure calculated by the first-order second-moment method. This index comprehensively considers the uncertainties of factors such as material strength, geometric parameters, and load effects. After extreme load verification, the design parameters of the ultra-high tower ensure that the structure can still maintain sufficient safety margin under the most severe conditions.

[0087] The design method for ultra-high wind turbine towers in this application has been described above. The design system for ultra-high wind turbine towers in this application is described below. One embodiment of the design system for ultra-high wind turbine towers in this application includes:

[0088] The input module is used to input the load conditions of the ultra-high wind turbine tower into the finite element analysis system. The traditional cylindrical section is transformed into a polygonal shape through a geometric optimization algorithm to obtain the polygonal section parameters of a regular hexagonal shape. The polygonal section parameters include the bottom diameter, the top diameter, and the taper ratio.

[0089] The splitting module is used to establish a stress distribution model based on the multi-faceted cross-section parameters, and to perform segmentation and piece-by-piece splitting of the ultra-high tower structure to obtain multiple standard tower segments and multiple fan-shaped piece-by-piece units.

[0090] The optimization module is used to perform variable thickness trapezoidal optimization processing on the equal thickness plate structure according to the stress cloud diagram distribution of the fan-shaped segment unit, so as to obtain an unequal thickness irregular plate configuration from the bottom maximum thickness to the top minimum thickness.

[0091] The replacement module is used to replace the welding connection method with bolts based on the connection requirements of the unequal thickness irregular plate configuration, so as to obtain a plate connection system with high strength bolts and a segment connection system with bolted connecting plates.

[0092] The evaluation module is used to input the tower structure composed of the inter-segment connection system and the inter-section connection system into the dynamic verification model, and to perform quantitative evaluation of the structural stiffness performance to obtain the first-order bending mode frequency and the design parameters of the ultra-high tower.

[0093] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A design method for ultra-high wind turbine towers, characterized in that, The method comprises: Step S1: input the load condition of the ultra-high wind turbine tower drum into a finite element analysis system, perform multi-ribbed modification processing on the traditional cylindrical section through a geometric optimization algorithm, obtain the parameters of the regular hexagonal multi-ribbed section, and the parameters of the multi-ribbed section include the bottom diameter, the top diameter and the taper ratio; Step S2: establish a stress distribution model based on the multi-ribbed section parameters, perform segmented and sliced splitting processing on the ultra-high tower drum structure, and obtain a plurality of standard tower segments and a plurality of fan-shaped sliced units; Step S3: according to the stress nephogram distribution of the fan-shaped sliced unit, perform variable-thickness trapezoidal optimization processing on the equal-thickness plate structure, and obtain the unequal-thickness special-shaped plate configuration from the maximum thickness at the bottom to the minimum thickness at the top, including: inputting the plurality of fan-shaped sliced units into a refined finite element model, performing stress analysis processing on each fan-shaped slice through actual working condition load application, obtaining the stress nephogram distribution and stress gradient change data of each fan-shaped slice, identifying and analyzing the material distribution unevenness of the equal-thickness plate structure based on the stress nephogram distribution, determining the thickness optimization interval through the gradient change calculation of the stress value from 690 MPa to 200 MPa, and obtaining the stress distribution characteristics of the bottom high-stress area and the top low-stress area; according to the stress distribution characteristics, a material optimization mathematical model is established, the strength condition is taken as a constraint condition for topology optimization calculation and processing of thickness distribution, and the variable-thickness distribution parameters from the bottom thickness of 49 mm to the top thickness of 20 mm and the 1:5 slope transition parameters are obtained; based on the variable-thickness distribution parameters and the slope transition parameters, the thickness configuration verification processing is performed on each fan-shaped slice, the optimized thickness parameters are applied to the 168 fan-shaped slices through the minimum material usage calculation, and the unequal-thickness special-shaped plate configuration is obtained; Step S4: based on the connection requirement of the unequal-thickness special-shaped plate configuration, perform full-bolt replacement processing on the welding connection mode, and obtain the inter-slice connection system of high-strength bolts and the inter-segment connection system of bolted plates; Step S5: input the tower drum structure composed of the inter-slice connection system and the inter-segment connection system into a dynamics verification model, perform quantitative evaluation processing on the structural stiffness performance, and obtain the first-order bending modal frequency and the ultra-high tower drum design parameters.

2. The ultra-high wind electric tower drum design method according to claim 1, wherein, The step S1 comprises: Input the tower bottom bending moment load, shear load and axial force load of a 25-megawatt wind turbine into a three-dimensional finite element model, perform static and dynamic simulation analysis processing, obtain the load distribution nephogram and stress concentration area identification result under extreme working conditions, perform geometric improvement analysis processing on the inertia moment deficiency problem of the traditional cylindrical section through the inertia moment calculation, perform multi-ribbed modification processing on the traditional cylindrical section, obtain the equivalent diameter parameters and the stiffness parameters of the regular hexagonal section, and perform optimization calculation processing on the tower drum bottom diameter demand according to the stiffness parameters, input the highway transportation limitation condition as a constraint condition into the geometric optimization algorithm, and obtain the tapered tower drum geometric parameters. ​ ​ Based on the conical tower drum geometric parameters, the anti-bending inertia moment and the anti-torsional inertia moment are verified and calculated, and through comparison and analysis with the performance of the cylindrical section with the same diameter, the multi-rib section parameters formed by the bottom diameter, the top diameter and the taper ratio are obtained.

3. The ultra-high wind electric tower design method of claim 1, wherein, The step S2 comprises: The multi-rib section parameters are input into a three-dimensional finite element model, stress analysis of the 333-meter super-high tower drum structure is carried out through full-load simulation, and the bending moment distribution envelope, the shear force distribution envelope and the axial force distribution envelope along the tower height direction are obtained; Based on the bending moment distribution envelope, the shear force distribution envelope and the axial force distribution envelope, longitudinal segmentation analysis of the tower drum structure is carried out, and according to the stress continuity principle, the 333-meter tower drum is divided into 21 standard segments with a height of 16.5 meters, and the segmentation configuration parameters of the multi-segment standard tower segments are obtained; According to the segmentation configuration parameters, circumferential segmentation calculation of each standard tower segment is carried out, the regular hexagon section is divided into 8 sectors according to 2 edge lengths as a unit, and the multi-sector segment units with a length of 16.5 meters, a width of 2.5-3.8 meters and a weight of 20 tons or less are obtained; Based on the geometric parameters of the multi-sector segment units, the inter-plate connection position is optimized and selected, the connection line is set at the midpoint of the multi-rib edge through shear stress minimization calculation, and the connection interface parameters of 168 sector segments and the load transfer path configuration are obtained.

4. The ultra-high wind electric tower drum design method according to claim 1, wherein, The step S4 comprises: A fatigue analysis model is established based on the unequal-thickness profile plate configuration, fatigue life calculation and processing of the welding connection mode are performed by combining the nominal stress method and the local stress method, and 2 times cycle load under the weld fatigue failure risk assessment results and bolt connection fatigue strength comparison data are obtained. According to the fatigue failure risk assessment results, the inter-plate connection mode is designed by bolting, the anti-slippage coefficient is ensured to be greater than or equal to 0.45 through sandblasting treatment of the connection interface to reach the Sa2.5 level, the inter-plate connection parameters of M30 grade 10.9 high-strength bolts and the connection configuration of 2048 bolts are obtained; Based on the connection configuration, the external joint plate bolt design of the inter-segment connection structure is carried out, 256 M30 bolts are applied to each interface through pre-buried high-strength bolt holes to realize fast positioning, the inter-segment connection system of the 30mm-thick joint plate and the double-row arrangement parameters with a bolt spacing of 150mm are obtained; The inter-plate connection configuration and the inter-segment connection system are input into a fatigue verification model, and through non-looseness verification processing of 10.9-grade bolts under 2x times cyclic load, the inter-plate connection system of the high-strength bolts and the inter-segment connection system of the bolted plate are obtained with a safety factor ≥1.

8.

5. The ultra-high wind electric tower drum design method according to claim 4, wherein, The fatigue analysis model is established based on the unequal-thickness special-shaped plate configuration, the nominal stress method and the local stress method are combined to calculate the fatigue life of the welding connection mode, including: The preset fatigue load spectrum is taken as an input condition, and 2x The fatigue load parameters and stress cycle range data of the welded joint and the bolt connection are obtained through equivalent cycle number calculation corresponding to 25-year design life. Based on the fatigue load parameters, the stress concentration coefficient of the heat-affected zone of the welded joint is analyzed, the stress amplitude at the root of the weld is calculated by the nominal stress method, and the crack initiation position is analyzed by the local stress method, the welded joint fatigue strength 210MPa and the stress concentration coefficient 2.8 of the weld failure risk data are obtained; According to the weld failure risk data, the fatigue strength of the Q690D base material is calculated and compared, the difference between the base material fatigue strength 355MPa and the welded joint fatigue strength 210MPa is analyzed through S-N curve, and the comparison result is obtained; Based on the comparison result, a bolt connection fatigue analysis model is established, and through high-strength bolt material characteristics and pre-tightening force action mechanism analysis and processing, the 2x Cyclic load under the risk assessment results of weld fatigue failure and the comparison data of the bolt connection fatigue strength.

6. The ultra-high wind electric tower drum design method of claim 1, wherein, The step S5 comprises: The connecting characteristics of the inter-plate connecting system and the inter-segment connecting system are input into a three-dimensional finite element dynamics model, and a dynamics analysis model and a structural mass matrix of a 333-meter complete tower are obtained through a complete tower modeling process including all geometric parameters, material properties and connecting characteristics; Modal analysis calculation processing is performed on the tower structure based on the dynamics analysis model, and the first 10 natural frequencies and corresponding modes of the tower are extracted through an eigenvalue solving algorithm, and frequency parameters and mode characteristic data of the first-order bending mode, the second-order bending mode and the torsional mode are obtained; The vibration avoidance verification processing is performed on the fan 1P frequency resonance risk based on the frequency parameters, and the first-order bending mode frequency is compared with the critical frequency of 0.25 Hz to ensure that the first-order frequency is greater than or equal to 0.25 Hz to avoid resonance, and the first-order bending mode frequency and dynamic characteristic verification results that meet the resonance avoidance requirement are obtained; Based on the dynamic characteristic verification result, the displacement response under extreme load is quantitatively calculated, and the displacement under the working condition of 50-year wind load 55m / s and seismic load 0.4g is calculated, and the tower top displacement 1.8m is less than the allowable value 3.5m and the structural reliability index 3.7, and the super-high tower design parameters are obtained.

7. An ultra-high wind electric tower drum design system, characterized in that, The super-high wind turbine tower design system for implementing the super-high wind turbine tower design method according to any one of claims 1 to 6 comprises: An input module for inputting the load conditions of the super-high wind turbine tower into the finite element analysis system, and performing a multi-ribbed modification processing on the traditional cylindrical section through a geometric optimization algorithm to obtain a regular hexagonal multi-ribbed section parameter, the multi-ribbed section parameter including a bottom diameter, a top diameter and a taper ratio; A splitting module for establishing a stress distribution model based on the multi-ribbed section parameter, and performing a segmented and sliced splitting processing on the super-high tower structure to obtain a plurality of standard tower segments and a plurality of fan-shaped sliced units; An optimization module for performing a variable-thickness trapezoidal optimization processing on the equal-thickness plate structure according to the stress nephogram distribution of the fan-shaped sliced unit to obtain a non-equal-thickness special-shaped plate configuration with a maximum thickness at the bottom to a minimum thickness at the top; A replacement module for performing a full-bolting replacement processing on the welding connection mode based on the connection requirements of the non-equal-thickness special-shaped plate configuration to obtain an inter-plate connecting system of high-strength bolts and an inter-segment connecting system of bolted plates; An evaluation module for inputting the tower structure composed of the inter-plate connecting system and the inter-segment connecting system into a dynamics verification model, and performing a quantitative evaluation processing on the structural stiffness performance to obtain a first-order bending mode frequency and a super-high tower design parameter.

Images