Design method and system for three-section combined structure of ultra-high wind turbine tower

Abstract

The present application relates to the field of data processing technology, and discloses a method and system for designing a three-section combined structure of an ultra-high wind power tower. The method comprises: analyzing wind speed distribution data through a wind load-structural dynamics-material mechanics coupling algorithm to obtain the stiffness distribution function and frequency avoidance constraints of the three functional partitions, performing multi-objective optimization on the lower truss section to obtain the geometric parameter configuration, performing fluid-solid coupling vibration control design on the middle multi-faceted transition section, performing aeroelastic instability prevention and control design on the upper cylindrical section, performing integrated dynamic coordination processing on the three-section structure, and performing multi-working condition verification through a large eddy simulation-finite element coupling verification algorithm to obtain the target design parameters. The present application solves the technical problem that existing wind power tower technology cannot break through the 360-meter ultra-high height limit and simultaneously meet the requirements of structural safety, economy, and constructability.

Description

Technical Field

[0001] The present application relates to the field of data processing technology, and in particular to a design method and system for a three-section combined structure of an ultra-high wind power generation tower. Background Art

[0002] With the accelerating global energy transition, existing wind turbine technologies are evolving towards higher power and higher altitudes. Offshore wind turbine capacity is rapidly increasing from 8-20MW to 30-50MW, while onshore wind towers are transitioning from 5MW to 30MW. To access high-quality wind resources at altitudes of 60-700 meters, mainstream wind farms are requiring tower heights to be increased from the current 120-160 meters to 190 meters, with plans to exceed 360 meters to ensure safe blade operation in high-quality wind conditions. Existing wind turbine tower technologies primarily utilize steel-concrete composite towers, traditional cylindrical steel towers, and truss towers.

[0003] However, existing wind turbine tower technology suffers from significant structural flaws, high costs, and transportation limitations. The concrete-steel interface of steel-concrete composite towers is prone to microcracks and exhibits poor dynamic performance, posing resonance and collapse risks. Traditional cylindrical steel towers are difficult to transport on public roads, and to meet rigidity requirements, the steel plate wall thickness in the mid-bottom section reaches 60-90mm, resulting in significant material waste. When the upper and middle sections of a truss-type tower are too high, insufficient anti-sway, bending, and seismic performance becomes a bottleneck.

[0004] Based on an analysis of the limitations of existing technologies, as tower heights rise above 300 meters and toward 360 meters, traditional single structural forms are unable to simultaneously address the conflicting demands for high strength, transportability, and vibration resistance. Existing technologies lack a multi-physics coupling design approach specifically for ultra-tall wind towers, and are unable to systematically address the coordinated optimization of wind loads, structural dynamics, and material mechanics. This leads to technical bottlenecks at heights exceeding 360 meters, such as unavoidable resonant frequencies, excessive material usage, high transportation costs, and lengthy installation cycles. There is an urgent need to break through traditional design concepts and establish a systematic design approach for ultra-tall wind towers. Summary of the Invention

[0005] The present application provides a method and system for designing a three-section combined structure of an ultra-high wind power tower, which is used to solve the technical problem that existing wind power tower technology cannot break through the 360-meter ultra-high height limit and simultaneously meet the requirements of structural safety, economy and constructability.

[0006] In the first aspect, the present application provides a three-section combined structural design method for an ultra-high wind power generation tower, and the three-section combined structural design method for an ultra-high wind power generation tower includes: performing multi-physics field collaborative analysis on the wind speed distribution data of the target wind farm through a wind load-structural dynamics-material mechanics coupling algorithm to obtain the stiffness distribution function and frequency avoidance constraints of the three-section functional partitions; performing multi-objective optimization processing on the geometric parameters of the lower truss section according to the stiffness distribution function to obtain the optimized configuration of the diagonal brace crossing angle, the main diagonal tube specification and the wire rope-concrete composite section; taking the dynamic characteristics of the lower truss section as the boundary condition, performing fluid-solid coupling vibration control design on the middle polygonal transition section to obtain the geometric parameters of the 12-sided polygon, the TMD device parameters and the layout scheme of 24 viscous dampers; based on the vibration control results of the middle polygonal transition section, performing aeroelastic instability prevention and control design on the upper cylindrical section to obtain the number distribution of the multi-piece cylindrical structure, the trapezoidal longitudinal rib configuration and the layered pre-tension distribution; The dynamic characteristics of the three-section structure are integrated and coordinated to obtain the frequency avoidance matrix of the entire tower and the impedance matching parameters of the inter-segment connections; the three-section combined structure design scheme is subjected to multi-working condition coupling verification through the large eddy simulation-finite element coupling verification algorithm to obtain the target design parameters.

[0007] In a second aspect, the present application provides a three-section combined structure design system for an ultra-high wind power generation tower, the three-section combined structure design system for an ultra-high wind power generation tower comprising:

[0008] The analysis module is used to perform multi-physics collaborative analysis on the wind speed distribution data of the target wind farm using a wind load-structural dynamics-material mechanics coupling algorithm to obtain the stiffness distribution function and frequency avoidance constraints of the three functional partitions;

[0009] The optimization module is used to perform multi-objective optimization on the geometric parameters of the lower truss segment based on the stiffness distribution function, and obtain the optimal configuration of the diagonal brace crossing angle, main diagonal tube specifications, and wire rope-concrete composite cross section;

[0010] The control module is used to design the fluid-structure interaction vibration control of the middle polygonal transition section using the dynamic characteristics of the lower truss section as boundary conditions, obtaining the geometric parameters of the 12-sided polygon, the parameters of the TMD device, and the layout of the 24 viscous dampers;

[0011] The design module is used to design the aeroelastic instability prevention and control of the upper cylindrical section based on the vibration control results of the middle multi-faceted transition section, and obtain the number of slices, trapezoidal longitudinal rib configuration, and layered pre-tension distribution of the multi-slice cylindrical structure;

[0012] The coordination module is used to integrate the dynamic characteristics of the three-segment structure into a coordinated process to obtain the frequency avoidance matrix of the entire tower and the impedance matching parameters of the inter-segment connections;

[0013] The verification module is used to perform multi-condition coupling verification on the three-section combined structure design scheme through the large eddy simulation-finite element coupling verification algorithm to obtain the target design parameters.

[0014] The technical solution provided in this application uses a multi-physics collaborative analysis method established through a wind load-structural dynamics-material mechanics coupling algorithm, breaking through the limitations of independent analysis of a single physical field in existing technologies. This coupling algorithm simultaneously considers the interaction between wind load and structural deformation, and the coupling relationship between structural dynamic response and material mechanics constraints, achieving a systematic optimization design for a 360-meter ultra-high wind tower. This effectively addresses the resonance risks, material waste, and potential collapse hazards that occur in traditional wind towers above 185 meters. A multi-objective optimization method based on a stiffness distribution function achieves precise solution of the geometric parameters of the lower truss segment by establishing a comprehensive objective function for weight minimization, stress control, displacement limitation, and frequency requirements. The design of a diagonal brace cross angle of 50 degrees plus or minus 5 degrees minimizes the drag coefficient. The optimized configuration of the steel cable-concrete composite section increases the equivalent stiffness by 35% compared to traditional pure steel structures, while increasing weight by only 12%. The fluid-structure coupling vibration control design establishes a vortex shedding suppression mechanism for a 12-sided polygonal body, combined with the TMD device parameters and the optimized arrangement of 24 viscous dampers, to increase the structural damping ratio from the traditional 0.5% to 2.8%, effectively solving the problem of wind-induced vibration in the middle transition section. The aeroelastic instability prevention and control design determines the number of slices in the multi-cylindrical structure through Reynolds number correlation optimization, combined with the trapezoidal longitudinal rib configuration and layered pre-tension distribution, to increase the critical wind speed of aeroelastic instability in the upper cylindrical section from 45 meters per second to 65 meters per second. The integrated dynamic coordination processing ensures that the first three frequencies of 0.12Hz, 0.31Hz, and 0.58Hz avoid the impeller pass frequency of 0.15-0.2Hz and its multiples, eliminating the risk of resonance.

[0015] The large eddy simulation-finite element coupling verification algorithm establishes a large-scale coupling verification matrix and uses a time-domain fluid-solid coupling calculation method to verify the design scheme, ensuring that key safety indicators such as maximum displacement, maximum stress, and fatigue damage meet the design requirements, and verifying the feasibility of the ultra-high wind turbine tower design. The comprehensive technical effects of the present invention are reflected in: a significant reduction in steel consumption to achieve significant weight reduction, a significant reduction in single-stage tower transportation costs, a significant shortening of the installation cycle, a significant reduction in annual resonance downtime losses, and a significant increase in power generation revenue. At the same time, the use of weather-resistant composite steel plates achieves long-term maintenance-free, the one-time hot rolling technology of wedge plates effectively saves materials, the non-circumferential seam welding and internal rib-assisted ribs reduce stress concentration, and the modular flange adopts a thickened design with high-strength prestressed bolts and multiple shear keys to ensure connection reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0017] Figure 1 A schematic diagram of an embodiment of a method for designing a three-section combined structure of an ultra-high wind power tower in an embodiment of the present application;

[0018] Figure 2 This is a schematic diagram of an embodiment of the three-section combined structure design system of the ultra-high wind power tower in the embodiment of the present application. DETAILED DESCRIPTION

[0019] The embodiments of the present application provide a method and system for designing a three-section combined structure of an ultra-high wind power tower. The terms "first", "second", "third", "fourth", etc. (if any) in the specification and claims of this application and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments described herein can be implemented in an order other than that illustrated or described herein. In addition, the terms "including" or "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or apparatus that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units that are not explicitly listed or are inherent to these processes, methods, products or apparatus.

[0020] For ease of understanding, the specific process of the embodiment of the present application is described below. Figure 1 In the embodiment of the present application, an embodiment of the method for designing a three-section combined structure of an ultra-high wind power tower includes:

[0021] Step S101: Perform multi-physics collaborative analysis on the wind speed distribution data of the target wind farm using a wind load-structural dynamics-material mechanics coupling algorithm to obtain stiffness distribution functions and frequency avoidance constraints for three functional partitions;

[0022] Step S102: performing multi-objective optimization on the geometric parameters of the lower truss segment according to the stiffness distribution function to obtain the optimal configuration of the diagonal brace crossing angle, main diagonal tube specifications, and steel wire rope-concrete composite cross section;

[0023] Step S103: Using the dynamic characteristics of the lower truss section as boundary conditions, perform fluid-structure coupling vibration control design on the middle polygonal transition section to obtain the geometric parameters of the 12-sided polygon, TMD device parameters, and the layout of the 24 viscous dampers;

[0024] Step S104: Based on the vibration control results of the middle multi-faceted transition section, the upper cylindrical section is designed for aeroelastic instability prevention and control, and the number of slices, trapezoidal longitudinal rib configuration, and layered pre-tension distribution of the multi-slice cylindrical structure are obtained;

[0025] Step S105: Perform integrated dynamic coordination processing on the dynamic characteristics of the three-segment structure to obtain the frequency avoidance matrix of the entire tower and the impedance matching parameters of the inter-segment connections;

[0026] Step S106: Perform multi-condition coupling verification on the three-section combined structure design scheme through a large eddy simulation-finite element coupling verification algorithm to obtain target design parameters.

[0027] It is understandable that the execution subject of this application can be the ultra-high wind power tower three-section combined structure design system, or a terminal or server, which is not limited here. The embodiment of this application is described by taking the server as the execution subject as an example.

[0028] Specifically, real-time wind speed distribution data is collected from the target wind farm within an altitude range of 60 to 700 meters. The data includes parameters such as wind speed values, wind direction angles, and turbulence intensity at different altitudes. The wind speed gradient function corrects the original wind speed data for altitude according to the surface roughness index to calculate the precise wind load values ​​for each altitude segment. The wind load distribution characteristics are then input into the structural dynamics model, which considers the mass distribution, damping characteristics, and stiffness changes of the tower. The displacement response and stress distribution data for each altitude segment are obtained by solving the equation of motion. When constructing the stiffness distribution function based on the displacement response data, the system analyzes the characteristics of the 0-120 meter segment that needs to withstand the maximum wind load and gravity load, and designs it as a high-stiffness segment. The 120-200 meter segment serves as a transition zone for mechanical properties, with a gradient of decreasing stiffness. The 200-360 meter segment has relatively small wind loads and is designed as a lightweight, low-stiffness segment. During the establishment of frequency avoidance constraints, the system extracts the impeller passing frequency of 0.15-0.2Hz as the reference frequency, and generates the avoidance matrix of the first three frequencies through mathematical calculations to ensure that the tower's natural frequency is staggered with the impeller excitation frequency to avoid resonance.

[0029] The stiffness distribution function was input as a constraint into the optimization model. The model simultaneously considered four objectives: weight minimization, stress control, displacement limitation, and frequency requirements. Through iterative calculations, the model determined the main inclined tube diameter range of 500-1500 mm, the wall thickness range of 8-16 mm, the brace angle range of 45-55 degrees, and the chord diameter range of 20-30 mm. During the drag coefficient minimization calculation, the system established a function that correlated the brace angle with the drag coefficient. Numerical analysis revealed that a 50-degree brace intersection angle minimized the drag coefficient, creating the optimal force transmission path. The wire rope pretension optimization design was based on the principle of maximizing the equivalent stiffness of the composite section. The stiffness contributions of the three materials, wire rope, steel pipe, and concrete, were calculated to determine the pretension value and wire rope specifications. Ultimately, the optimized main inclined tube specifications, brace intersection angle, and wire rope parameters were input into the C50 concrete casting process to form a steel pipe-wire rope-concrete composite load-bearing system.

[0030] The dynamic characteristics of the lower truss section were used as boundary conditions and input into the fluid-structure coupling control model to design the middle transition section. The model uses computational fluid dynamics methods to analyze the flow field characteristics around the 12-sided polygonal body and calculate the Strouhal number and the corresponding vortex shedding frequency. Based on the vortex shedding frequency data, the polygonal geometry is rounded to reduce the vortex shedding intensity and the amplitude of wind-induced vibration by changing the radius of curvature of the corners. During the TMD device parameter design process, the system calculates the mass ratio of the TMD system to 0.02, the frequency ratio to 0.95, and the damping ratio to 0.1 based on the polygonal geometry parameters to ensure the best tuning relationship between the TMD device and the main frequency of the structure. The layout optimization of the 24 viscous dampers uses a position iteration algorithm. Using the TMD device parameters as constraints, the optimal installation position, damping coefficient of 2000 kilonewton-seconds per meter, and velocity index of 0.3 for each damper are calculated to form a vibration control layout plan.

[0031] Based on the results of vibration control, the aeroelastic instability prevention and control design of the upper cylindrical section is carried out. The system inputs the vibration control data of the middle transition section into the aeroelastic stability discrimination model, and calculates key parameters such as the lift coefficient, drag coefficient and aerodynamic derivatives through eigenvalue solution. The Reynolds number correlation method is used in the process of optimizing the number of blades distribution. According to the wind speed conditions and structural requirements of different height segments, the distribution scheme of 18 blades for 200-280 meters, 12 blades for 280-320 meters, and 6 blades for 320-360 meters is determined. In the design of the trapezoidal longitudinal rib configuration, the system calculates the variation pattern of rib height from 200 to 800 mm, the optimal value of rib width ratio of 0.6 and the uniform arrangement of rib spacing of 600 mm, and verifies the design scheme through aerodynamic drag reduction analysis. The pretension optimization calculation inputs the trapezoidal longitudinal rib configuration into the geometric stiffness matrix, resulting in a pretension gradient distribution of 150 kN at the bottom layer, 120 kN at the middle layer, and 90 kN at the top layer. The layered steel cable layout design determines the spatial distribution pattern for the first layer at 0, 120, and 240 degrees, and the second layer at 60, 180, and 300 degrees. The dynamic characteristics of the three-segment structure are integrated and coordinated into a segmented coupled dynamic model. This model establishes the mass, damping, and stiffness matrices for the entire tower, reflecting the coupled characteristics of the three segments. Frequency ratios between adjacent segments are coordinated to ensure they remain within the range of 0.7-1.3 to avoid local resonance. Modal continuity constraints ensure smooth vibration transmission at inter-segment connections, preventing stress concentration. During the construction of the frequency avoidance matrix for the entire tower, the system calculates the first three frequencies of 0.12 Hz, 0.31 Hz, and 0.58 Hz to ensure they avoid the impeller pass frequency and its multiples. Impedance matching optimization for inter-segment connections was achieved through vibration energy transfer analysis, calculating connection stiffness and damping parameters to maintain a stress concentration factor below 1.5. The overall design scheme was fully validated using a large eddy simulation (LES)-finite element method coupled verification algorithm. The LES numerical test platform established a three-dimensional computational domain encompassing 15 diameters upwind, 30 diameters leeward, and 10 diameters lateral to the tower, with a total mesh size exceeding 20 million to ensure computational accuracy. A multi-condition combination of wind speeds from 3 to 25 meters per second, turbulence intensities from 5% to 25%, and wind angles from 0 to 180 degrees was used to form a coupled verification matrix encompassing 525 verification conditions. The fluid-structure interaction algorithm, employing a time-domain solution, calculated the interaction between the fluid and the structure in real time, obtaining key indicators such as maximum displacement, maximum stress, and fatigue damage. Verification results showed that the maximum displacement was less than 1 / 116 of the tower height, the maximum stress was less than 254 MPa, and the fatigue damage was less than 0.5, meeting the 360-meter super-height and 25-year design life requirements.

[0032] It should be noted that in this application, the middle polygonal transition section and the upper cylindrical section are mainly designed as keel reinforcement support points. The keel structure is a trapezoidal area with a clever combination of longitudinal flanges. An inner annular flange is installed every 4 meters in the middle polygonal transition section and the upper cylindrical section. The structure is adjustable by tightening the wire rope.

[0033] In a specific embodiment, the process of executing step S101 may specifically include the following steps:

[0034] Obtain wind speed distribution data within the target wind farm's height range of 60 to 700 meters, calculate the wind load field using the wind speed gradient function, and obtain the wind load distribution characteristics at different height segments;

[0035] The wind load distribution characteristics are input into the structural dynamics model for coupled solution to obtain the displacement response and stress distribution of each height segment;

[0036] The stiffness distribution function is constructed segmentally and continuously based on the displacement response, and the gradient distribution of the stiffness coefficient of the 0-120m segment, the 120-200m segment, and the 200-360m segment is obtained;

[0037] Frequency avoidance constraints are established according to the impeller passing frequency of 0.15-0.2 Hz to perform resonance avoidance calculation, and the avoidance matrix and safe frequency bandwidth parameters of the first three frequencies are obtained.

[0038] Specifically, wind speed distribution data within the target wind farm's height range of 60 to 700 meters is obtained through a multi-layer wind speed sensor array. The sensors are arranged at a vertical interval of 20 meters to collect instantaneous wind speed, average wind speed, and turbulence intensity data at each height point. The wind speed gradient function corrects the original wind speed data for height according to the exponential law. This function takes into account the impact of surface roughness on wind speed and calculates the wind speed value at any height by raising the exponential power of the height ratio to the reference height. The exponential value is determined according to the surface type. The wind load field calculation substitutes the corrected wind speed data into the wind pressure calculation formula. Combined with the air density, drag coefficient, and windward area parameters, the wind load values ​​for each height segment are calculated layer by layer to form a wind load distribution characteristic curve from bottom to top.

[0039] When the wind load distribution characteristics are input into the structural dynamics model, the model discretizes the tower into multiple node units, each of which bears the wind load at the corresponding height. The structural dynamics model establishes a mass matrix to reflect the mass distribution of each segment, a damping matrix to reflect the damping characteristics of the material, and a stiffness matrix to reflect the change in structural stiffness. The dynamic response of the structure under wind load is calculated by solving the equation of motion. During the coupled solution process, wind load and structural deformation affect each other. Structural deformation changes the windward area and thus affects the magnitude of wind load, forming a coupled calculation cycle of wind-structure interaction. The displacement response calculation obtains the horizontal displacement, vertical displacement, and angular displacement of each height node, and the stress distribution calculation obtains the bending stress, axial stress, and shear stress distribution law of each section.

[0040] When constructing the segmented continuous stiffness distribution function based on the displacement response, the displacement gradient change law of each height segment is analyzed to determine the stiffness requirement. The small displacement response of the 0-120 meter segment indicates that high-rigidity support is required, and the maximum stiffness coefficient is taken as the benchmark stiffness. The displacement response of the 120-200 meter segment shows an increasing trend, and the stiffness coefficient is distributed according to a linear decreasing law. The decrease amplitude is determined by the displacement change rate. The displacement response of the 200-360 meter segment is large but the load is relatively small. The stiffness coefficient takes a smaller value to meet the lightweight requirements. The three segments of stiffness coefficients are connected by a continuous function, and the stiffness values ​​transition smoothly at the connection between segments to avoid stress concentration caused by sudden stiffness changes. The gradient distribution is numerically fitted to obtain a continuous function expression for the change of stiffness with height.

[0041] When establishing frequency avoidance constraints based on the impeller pass-through frequency, first determine the pass-through frequency range of 0.15-0.2Hz corresponding to the impeller speed range, and then calculate the first three natural frequencies of the tower structure. The resonance avoidance calculation adjusts the structural parameters to make the natural frequency avoid the impeller pass-through frequency and its multiples. The specific method is to leave a safe frequency bandwidth of 0.02Hz above and below the impeller pass-through frequency. The avoidance matrix of the first three frequencies arranges the tower natural frequency, impeller pass-through frequency and its multiples in a matrix form, and checks whether the difference between any two frequency values ​​in the matrix meets the safe bandwidth requirements. The safe frequency bandwidth parameter is determined based on the structural damping ratio and the excitation amplitude. The smaller the damping ratio, the larger the safe bandwidth required.

[0042] In a specific embodiment, the process of executing step S102 may specifically include the following steps:

[0043] Inputting the stiffness distribution function into a multi-objective optimization model to solve the truss geometric parameters, thereby obtaining the main oblique tube diameter range, wall thickness range, oblique brace angle range, and chord diameter range;

[0044] Based on the principle of minimizing the drag coefficient, the angle range of the diagonal brace is optimized and calculated to obtain a diagonal brace crossing angle of 50 degrees plus or minus 5 degrees and a corresponding drag coefficient;

[0045] The wire rope pre-tension is optimized according to the objective of maximizing the equivalent stiffness of the composite section, and the wire rope specification parameters and pre-tension values ​​corresponding to the main inclined tube specifications are obtained;

[0046] The diameter range of the main inclined tube, the crossing angle of the diagonal brace and the specification parameters of the steel wire rope are input into the C50 concrete casting process to construct a composite section, thereby obtaining an optimized configuration of the steel wire rope-concrete composite section.

[0047] Specifically, when the stiffness distribution function is input into the multi-objective optimization model, the optimization model establishes multiple objective functions including weight minimization, stress control, displacement constraints, and frequency matching, and sets strength constraints, geometric constraints, and manufacturing process constraints as boundary conditions. During the solution of the truss geometric parameters, the model determines the stiffness requirements of each section based on the stiffness distribution function, and through iterative calculations, determines that the diameter range of the main inclined tube is between 500-1500 mm. The lower limit of this range is limited by the minimum load-bearing capacity, and the upper limit is limited by manufacturing and transportation. The wall thickness range is between 8-16 mm. The lower limit meets the stability requirements of thin-walled structures, and the upper limit controls weight and cost. The brace angle range is between 45-55 degrees. Within this range, the truss has good load-bearing and force transmission performance. The chord diameter range is between 20-30 mm to ensure the strength requirements of the chord under tension and compression loads.

[0048] When optimizing the diagonal brace angle based on the principle of minimizing the drag coefficient, a function is established to determine the relationship between the diagonal brace angle and the drag coefficient. This function takes into account the law of the windward area of ​​the truss changing with the angle and the flow characteristics of the airflow around the truss. During the optimization calculation process, the angle range of 45-55 degrees is subdivided into 21 calculation points, with each point spaced 0.5 degrees apart, and the drag coefficient values ​​at each angle are calculated separately. The calculation results show that the drag coefficient shows a trend of first decreasing and then increasing with the change of angle, reaching a minimum value at 50 degrees. The diagonal brace cross angle range of 50 degrees plus or minus 5 degrees takes into account both the minimization of wind resistance and the tolerance of manufacturing errors. The corresponding drag coefficient is reduced by about 15 percentage points compared to the angle of 45 degrees and about 12 percentage points compared to the angle of 55 degrees.

[0049] When optimizing wire rope pretensioning based on the goal of maximizing the equivalent stiffness of the composite section, a composite cross-section mechanical model of the three materials, wire rope, steel pipe, and concrete, is established. The equivalent stiffness calculation takes into account the prestressing effect of the wire rope, the bending stiffness of the steel pipe, and the compressive stiffness of the concrete. These three factors work together through cross-sectional geometric relationships. During the optimization design process, the steel pipe cross-sectional parameters, including outer diameter, wall thickness, and moment of inertia, are determined based on the specifications of the main inclined pipe. The wire rope specifications, including diameter, number of strands, and breaking strength, are then determined based on the inner diameter of the steel pipe. The pretension value is determined through optimization calculations to ensure that the wire rope remains tensioned under all operating conditions while avoiding excessive pretension that could cause local instability in the pipe. The wire rope specifications are matched to those of the main inclined pipe. Large-diameter steel pipes are equipped with high-strength wire rope, while small-diameter steel pipes are equipped with wire rope of the corresponding specifications.

[0050] When the C50 concrete casting process inputs the main inclined tube diameter range, diagonal brace crossing angles, and wire rope specifications, the casting process determines the concrete dosage and casting plan based on the steel tube inner diameter and wire rope layout. During the composite section construction process, the wire ropes are first arranged inside the steel tube according to the design plan. The wire ropes are laid axially along the tube and pre-tensioned. Then, C50 high-strength concrete is poured from the top of the tube, enveloping the wire ropes as the concrete flows, forming an integrated composite structure. The casting process controls the concrete slump and casting speed to ensure that the concrete fully fills the internal space of the tube and avoids air bubbles and voids. The optimized configuration of the wire rope-concrete composite section achieves higher equivalent stiffness and load-bearing capacity than a single material through the synergistic effect of the wire rope prestressing, the concrete compressive strength, and the confinement of the steel tube.

[0051] In a specific embodiment, the process of executing step S103 may specifically include the following steps:

[0052] The dynamic characteristics of the lower truss section are input into the fluid-structure coupling control model to calculate the flow around the polygon, and the Strouhal number and vortex shedding frequency of the 12-sided polygon are obtained;

[0053] Based on the vortex shedding frequency, the polygonal geometric shape is subjected to an arc-shaped processing to obtain arc radius parameters and surface pressure coefficient gradient geometric parameters of the 12-sided polygonal shape;

[0054] The mass-stiffness-damping collaborative design of the TMD system was performed based on the geometric parameters of the 12-sided polygon, and the TMD device parameters with a mass ratio of 0.02, a frequency ratio of 0.95, and a damping ratio of 0.1 were obtained;

[0055] The TMD device parameters were used as constraints to optimize the position of the viscous dampers, and an arrangement scheme of 24 viscous dampers with a damping coefficient of 2000 kN / m and a velocity index of 0.3 was obtained.

[0056] Specifically, the dynamic characteristics of the lower truss section are input into the fluid-structure interaction control model, a computational model that simultaneously considers the interaction between fluid flow and structural vibration. This model uses the natural frequency, modal vibration shape, and damping characteristics of the truss section as boundary conditions to establish the flow field calculation domain for the central polygonal transition section. The polygonal flow calculation numerically solves the fluid motion equations to analyze the velocity and pressure field distributions of the airflow around the 12-sided polygon. The Strouhal number is a dimensionless parameter that characterizes the relationship between vortex shedding frequency and flow velocity. It is obtained by statistically analyzing the periodic variations in vortex shedding on the leeward side of the polygon. The vortex shedding frequency is calculated by multiplying the Strouhal number by the incoming wind velocity and dividing it by the characteristic dimensions of the polygon. This frequency reflects the frequency characteristics of the periodic excitation of the structure by vortex shedding.

[0057] When the edges of a polygonal geometry are rounded based on the vortex shedding frequency, the rounding process refers to changing the originally sharp edges of the polygon into arc transitions to reduce airflow separation and vortex shedding intensity. During the process, the degree of rounding is determined according to the magnitude of the vortex shedding frequency. The higher the vortex shedding frequency, the more severe the airflow separation, and a larger arc radius is required for treatment. The arc radius parameter is determined through flow field analysis so that the vortex shedding frequency after rounding avoids the natural frequency of the structure. The surface pressure coefficient gradient reflects the improvement effect of the rounding process on the pressure distribution. The geometric parameters of the 12-sided polygon include key dimensions such as side length, inscribed circle diameter, circumscribed circle diameter and arc radius. These parameters are interrelated to form a geometric description. When the mass-stiffness-damping collaborative design of the TMD system is performed based on the geometric parameters of the 12-sided polygon, the TMD system is the abbreviation of the tempered mass damper, which is a device that suppresses the vibration of the main structure by the vibration of the additional mass block. Mass-stiffness-damping collaborative design involves simultaneously optimizing the mass, spring stiffness, and damper parameters of the TMD to achieve an optimal match. A mass ratio of 0.02 represents the ratio of the TMD mass to the structural mass. This ratio is determined by balancing control effectiveness and cost. A smaller value results in ineffective control, while a larger value increases the structural burden. A frequency ratio of 0.95 represents the ratio of the TMD frequency to the structural frequency. This ratio, slightly less than 1.0, achieves optimal tuning. A damping ratio of 0.1 represents the ratio of the TMD system's damping to its critical damping. This value is determined through optimization calculations to balance vibration suppression and energy dissipation.

[0058] When optimizing the placement of viscous dampers using TMD device parameters as constraints, viscous dampers dissipate vibration energy through the flow resistance of a viscous medium. Optimal placement involves determining the optimal damper installation location and parameters within the structure. The TMD device parameters are used as known conditions during the optimization process, and based on the TMD control effect, viscous dampers are further deployed to enhance vibration control. The damping coefficient of 2000 kilonewton-second-per-meter represents the proportional relationship between the damping force generated by the damper and velocity. This value is determined through structural response analysis and damper performance matching. The velocity exponent of 0.3 represents the nonlinear relationship between the damping force and velocity, ensuring stable control performance under varying vibration intensities. The layout of the 24 viscous dampers is determined using an optimization algorithm. The position coordinates, mounting angle, and connection method of each damper are determined, forming a uniformly distributed vibration control network.

[0059] In a specific embodiment, the process of executing step S104 may specifically include the following steps:

[0060] The vibration control results of the middle polygonal transition section are input into the aeroelastic stability discrimination model to solve the eigenvalues, and the lift coefficient, drag coefficient and aerodynamic derivative are obtained;

[0061] Based on the aerodynamic derivatives, the Reynolds number correlation optimization of the number of cylindrical segments is performed to obtain a distribution of the number of segments of a multi-slice cylindrical structure with 18 segments for 200-280 meters, 12 segments for 280-320 meters, and 6 segments for 320-360 meters;

[0062] Performing aerodynamic drag reduction design on the trapezoidal longitudinal ribs based on the number distribution, a trapezoidal longitudinal rib configuration with a rib height of 200-800 mm, a rib width ratio of 0.6, and a rib spacing of 600 mm was obtained;

[0063] The trapezoidal longitudinal rib configuration is input into the geometric stiffness matrix to perform pretension optimization calculation, and the pretension gradient values ​​of 150 kN for the bottom layer, 120 kN for the middle layer, and 90 kN for the top layer are obtained;

[0064] The steel wire rope is designed for layered arrangement based on the pre-tension gradient value, and a layered pre-tension distribution is obtained with the first layer at 0 degrees, 120 degrees, and 240 degrees and the second layer at 60 degrees, 180 degrees, and 300 degrees.

[0065] Specifically, when the vibration control results of the central polygonal transition section are input into the aeroelastic stability discrimination model, the vibration control results include the vibration reduction effect of the TMD device, the damping enhancement effect of the viscous damper, and the correction values ​​of the dynamic parameters of the transition section. The aeroelastic stability discrimination model is a mathematical model that analyzes whether a structure will experience aeroelastic instability under wind load. This model calculates the stability boundary of the interaction between the structure and the airflow through the eigenvalue solution method. The eigenvalue solution process establishes a coupled set of equations for the aerodynamic matrix and the structural dynamic matrix. The real and imaginary parts of the system eigenvalues ​​are obtained through numerical calculation. A negative real part of the eigenvalue indicates that the system is stable, while a positive real part indicates instability. The lift coefficient reflects the magnitude of the aerodynamic force perpendicular to the incoming flow direction, the drag coefficient reflects the magnitude of the aerodynamic force parallel to the incoming flow direction, and the aerodynamic derivative reflects the rate of change of the aerodynamic force with the angle of attack and pitch angular velocity. The three together describe the aerodynamic characteristics of the cylindrical section.

[0066] When optimizing the number of blades in a cylindrical segment based on aerodynamic derivatives, the Reynolds number is a dimensionless parameter that characterizes the ratio of a fluid's inertial force to its viscous force. Reynolds number-dependent optimization involves determining the optimal blade distribution based on the variation of the Reynolds number at different heights. The optimization process uses aerodynamic derivatives as constraints to analyze the aeroelastic stability performance under different blade configurations. A greater number of blades approximates the aerodynamic characteristics of a smooth cylinder, while a smaller number facilitates manufacturing and installation. For the 200-280-meter altitude range, where wind speeds are relatively high and the Reynolds number is relatively high, an 18-blade configuration is used. For the 280-320-meter altitude range, where wind speeds are moderate and the Reynolds number is moderate, a 12-blade configuration is used. For the 320-360-meter altitude range, where wind speeds are relatively low and the Reynolds number is moderate, a 6-blade configuration is used. The blade distribution of a multi-blade cylindrical structure is determined by calculating the Reynolds number at each height layer by layer. The specific number of blades per layer is then determined based on the relationship between the Reynolds number and the optimal number of blades.

[0067] When designing aerodynamic drag reduction using trapezoidal longitudinal ribs based on the number of ribs, the ribs are trapezoidal cross-section reinforcement ribs arranged along the axis of the cylinder. Aerodynamic drag reduction design involves optimizing the rib geometry to reduce airflow resistance. During the design process, the effects of varying rib heights on the surface friction coefficient were analyzed. The rib height range of 200-800 mm takes into account both drag reduction and structural strength requirements. The greater the height, the more significant the drag reduction effect, but the greater the weight increase. The rib width ratio of 0.6 represents the ratio of the rib's width to its height, determined through flow field analysis. A larger ratio increases the frontal area, while a smaller ratio affects structural strength. The rib spacing of 600 mm represents the distance between adjacent longitudinal ribs. This spacing is related to the cylinder diameter and the number of ribs, ensuring a uniform and reasonable distribution of the ribs. The final geometric parameters of the trapezoidal longitudinal rib configuration are determined by comprehensively considering drag reduction, structural strength, and manufacturing cost.

[0068] When the trapezoidal longitudinal rib configuration is input into the geometric stiffness matrix for prestress optimization calculations, the geometric stiffness matrix is ​​a stiffness matrix that takes into account the influence of prestressing effects on structural stiffness. Prestress optimization calculations refer to determining the optimal distribution of wire rope prestressing. During the calculation process, the geometric parameters of the trapezoidal longitudinal ribs are converted into cross-sectional characteristic parameters, including cross-sectional area, moment of inertia, and section modulus. Then, a geometric stiffness matrix that takes into account the prestressing effects is established. The prestressing gradient distribution is determined based on the load characteristics and stiffness requirements at different heights. The bottom layer of 150 kN corresponds to the maximum load area, requiring maximum prestressing. The middle layer of 120 kN corresponds to the load transition area, using medium prestressing. The top layer of 90 kN corresponds to the lightly loaded area, using a smaller prestressing. The prestressing gradient value is determined by an optimization algorithm to determine the optimal distribution while satisfying strength and stability constraints.

[0069] When designing the layered layout of wire ropes based on the pre-tension gradient value, the layered layout design refers to determining the spatial distribution pattern of the wire ropes at different height layers and different azimuth angles. During the design process, the tensioning force of each layer of wire ropes is determined based on the pre-tension gradient value, and then the azimuth angle layout of the wire ropes is determined based on the principle of uniform force distribution. The first layer forms a three-point uniform distribution at 0 degrees, 120 degrees, and 240 degrees. The second layer is staggered 60 degrees relative to the first layer at 60 degrees, 180 degrees, and 300 degrees. The two-layer staggered layout avoids stress concentration and ensures uniform force. The layered pre-tension distribution forms a wire rope tensioning plan by calculating the pre-tension value and spatial coordinates of each wire rope.

[0070] In a specific embodiment, the process of executing step S105 may specifically include the following steps:

[0071] The dynamic characteristics of the lower truss section, the middle polygonal transition section and the upper cylindrical section are input into a segmented coupled dynamic model for integrated modeling to obtain the mass matrix, damping matrix and stiffness matrix of the entire tower;

[0072] Based on the mass matrix, damping matrix and stiffness matrix of the whole tower, the frequency ratio of adjacent segments is coordinated and calculated to obtain a frequency ratio range of 0.7-1.3 and a modal vibration shape continuity constraint condition;

[0073] A frequency avoidance matrix is ​​established based on the frequency ratio range and continuity constraint conditions to perform resonance avoidance design, and a full-tower frequency avoidance matrix is ​​obtained with the first three frequencies being 0.12 Hz, 0.31 Hz, and 0.58 Hz, respectively.

[0074] The full-tower frequency avoidance matrix is ​​used as a constraint condition to optimize the impedance matching of the inter-segment connections, and impedance matching parameters of the inter-segment connections with smooth transmission of vibration energy and a stress concentration factor less than 1.5 are obtained.

[0075] Specifically, the dynamic characteristics of the lower truss segment, the middle polygonal transition segment, and the upper cylindrical segment are input into a segmented coupled dynamic model. The segmented coupled dynamic model is a mathematical model that couples three structurally distinct segments through connecting interfaces into an integrated structure. The integrated modeling process first extracts the mass distribution, stiffness distribution, and damping characteristics of each segment. The dynamic characteristics of the lower truss segment include truss node mass, member stiffness, and material damping. The dynamic characteristics of the middle polygonal transition segment include polygonal mass, bending stiffness, and TMD damping enhancement. The dynamic characteristics of the upper cylindrical segment include cylindrical wall mass, prestressed stiffness, and viscous damper contribution. The full-tower mass matrix is ​​formed by assembling the mass distributions of the three segments according to their height coordinates. The damping matrix comprehensively considers structural damping, material damping, and the damping effects of added damping devices. The stiffness matrix uniformly accounts for bending stiffness, axial stiffness, and prestressed geometric stiffness.

[0076] When performing a coordinated calculation of the frequency ratios of adjacent segments based on the mass matrix, damping matrix, and stiffness matrix of the entire tower, the frequency ratio coordination calculation refers to analyzing the natural frequency ratio relationship of adjacent structural segments to avoid local resonance. The coordination calculation process extracts the first three natural frequencies of each segment and calculates the frequency ratios of adjacent segments. The frequency ratio range of 0.7-1.3 represents the allowable range of the frequency ratios of adjacent segments. Too small or too large will lead to uncoordinated vibration transmission. The modal vibration continuity constraint requires that the slopes of the vibration modes of adjacent segments at the connection are continuous to avoid the dynamic amplification effect caused by sudden changes in the vibration modes. The constraint condition describes the displacement continuity and rotational continuity of the connection through mathematical expressions to ensure smooth transmission of vibration energy between segments.

[0077] When establishing a frequency avoidance matrix based on the frequency ratio range and continuity constraints, the frequency avoidance matrix is ​​a mathematical tool that arranges the structural frequencies and excitation frequencies in a matrix form to check for frequency conflicts. Resonance avoidance design adjusts structural parameters to allow the natural frequency to avoid the impeller pass frequency and its multiples. The first three frequencies of 0.12Hz, 0.31Hz, and 0.58Hz correspond to the first bending mode, second bending mode, and first torsional mode of the structure, respectively. The process of establishing the full-tower frequency avoidance matrix includes three steps: frequency extraction, matrix construction, and conflict checking. The difference between any two frequencies in the matrix must be greater than the safe frequency bandwidth to ensure that resonance does not occur.

[0078] When the full-tower frequency avoidance matrix is ​​used as a constraint to optimize the impedance matching of inter-segment connections, impedance matching optimization refers to the optimization process of adjusting the connection parameters to minimize the reflection of vibration waves when transmitting between segments. The inter-segment connection includes two interfaces: the connection between the truss and the polygonal segment, and the connection between the polygonal segment and the cylindrical segment. The impedance matching of each interface needs to consider the impedance difference between the two structures. The smooth transmission of vibration energy requires the impedance of the connection to be continuous. The impedance is equal to the square root of the product of stiffness and mass. Impedance matching is achieved by adjusting the stiffness of the connection. The constraint condition of a stress concentration factor of less than 1.5 limits the stress amplification factor at the connection. This requirement is achieved through the optimization of connection geometric parameters and the design of transition structures. The impedance matching parameters include the connection stiffness coefficient, the connection damping coefficient, and the geometric transition parameters, which form an optimization scheme for inter-segment connections.

[0079] In a specific embodiment, the process of executing step S106 may specifically include the following steps:

[0080] The three-section combined structure design was input into the large eddy simulation numerical test platform for flow field modeling, and a computational domain grid with a diameter of 15 times in the upwind direction, 30 times in the leeward direction, and 10 times in the lateral direction was obtained.

[0081] Based on the computational domain grid, multiple working condition combinations are performed for wind speeds of 3-25 meters per second, turbulence intensity of 5%-25%, and wind direction angles of 0-180 degrees to obtain a coupling verification matrix of 525 verification working conditions;

[0082] The coupling verification matrix is ​​input into the fluid-structure coupling algorithm to perform time domain response calculation, and verification results are obtained that the maximum displacement is less than 1 / 116 of the tower height, the maximum stress is less than 254 MPa, and the fatigue damage degree is less than 0.5;

[0083] Based on the verification results, the design parameters were finally confirmed and optimized to obtain the target design parameters that meet the 360-meter super-height requirement and the 25-year design life.

[0084] Specifically, when the three-section combined structure design is input into the large eddy simulation numerical test platform, the large eddy simulation numerical test platform is a computational platform that uses the large eddy simulation algorithm to solve fluid motion. The platform obtains accurate flow field information by directly solving large-scale vortex motion and modeling the influence of small-scale vortices. The flow field modeling process first determines the size of the computational domain based on the geometric dimensions of the three-section combined structure. 15 times the diameter in the upwind direction ensures the full development of the incoming flow, 30 times the diameter in the leeward direction ensures the full expansion of the wake, and 10 times the diameter in the lateral direction avoids the influence of boundary effects. The computational domain mesh is generated by combining structured and unstructured meshes. Boundary layer meshes are used on the surface of the structure to ensure the accurate capture of the near-wall flow. Tetrahedral meshes are used in the far field to reduce the amount of calculation. The total number of meshes is controlled within a reasonable range to balance the calculation accuracy and efficiency.

[0085] When performing multiple operating condition combinations based on the computational domain grid, multiple operating condition combinations refer to the arrangement and combination of different wind speeds, turbulence intensities, and wind direction angles to form a comprehensive set of verification operating conditions. Wind speeds of 3-25 meters per second cover the entire operating range of wind turbines from cut-in wind speed to cut-out wind speed, and are divided into 12 wind speed operating conditions at intervals of 2 meters per second. Turbulence intensities of 5%-25% reflect the turbulence levels under different terrain and meteorological conditions, and are divided into five turbulence intensity operating conditions at intervals of 5%. Wind direction angles of 0-180 degrees take into account the main wind direction of the wind turbine, and are divided into seven wind direction angle operating conditions at intervals of 30 degrees. 525 verification operating conditions are obtained through a complete combination of 12×5×7. The coupled verification matrix records the parameter combination of each operating condition in matrix form, with each row representing a specific verification operating condition, including wind speed value, turbulence intensity value, and wind direction angle value.

[0086] When the coupling verification matrix is ​​input into the fluid-structure coupling algorithm, the fluid-structure coupling algorithm is a numerical algorithm that simultaneously solves the fluid motion equations and the structural dynamics equations while taking into account the interaction between the two. The time-domain response calculation uses a time-stepping method to gradually solve the dynamic response of the structure under wind load. In each time step, the flow field is first calculated to obtain the wind load acting on the structure, and then the structural response is calculated to obtain the structural deformation and velocity. The structural motion information is then fed back to the flow field calculation to update the boundary conditions. The verification results include three key indicators: maximum displacement, maximum stress, and fatigue damage degree. The maximum displacement is less than 1 / 116 of the tower height, or less than 3.1 meters, to ensure that the structural stiffness meets the requirements. The maximum stress is less than 254 MPa to ensure material strength safety. The fatigue damage degree is less than 0.5 to ensure fatigue safety within the 25-year design life.

[0087] When the final confirmation and optimization adjustment of the design parameters are carried out according to the verification results, optimization adjustment refers to the process of correcting the design parameters that do not meet the requirements based on the results of the verification calculation. The confirmation process checks whether the calculation results under each verification condition meet the design requirements. If a certain indicator exceeds the limit, the corresponding design parameters need to be adjusted. Optimization adjustment includes two aspects: structural parameter adjustment and control parameter adjustment. Structural parameter adjustment involves the modification of cross-sectional dimensions, material strength and geometric shape. Control parameter adjustment involves the optimization of TMD parameters, damper parameters and pre-tension distribution. The target design parameters are obtained through multiple rounds of iterative optimization. After each round of optimization, verification calculations are re-performed until all indicators meet the requirements. Finally, a complete parameter set that meets the 360-meter super-height requirement and 25-year design life is determined.

[0088] The above describes the design method of the three-section combined structure of the ultra-high wind power tower in the embodiment of the present application. The following describes the design system of the three-section combined structure of the ultra-high wind power tower in the embodiment of the present application. Figure 2 In the embodiment of the present application, an embodiment of the three-section combined structure design system of the ultra-high wind power tower includes:

[0089] The analysis module is used to perform multi-physics collaborative analysis on the wind speed distribution data of the target wind farm using a wind load-structural dynamics-material mechanics coupling algorithm to obtain the stiffness distribution function and frequency avoidance constraints of the three functional partitions;

[0090] The optimization module is used to perform multi-objective optimization on the geometric parameters of the lower truss segment based on the stiffness distribution function, and obtain the optimal configuration of the diagonal brace crossing angle, main diagonal tube specifications, and wire rope-concrete composite cross section;

[0091] The control module is used to design the fluid-structure interaction vibration control of the middle polygonal transition section using the dynamic characteristics of the lower truss section as boundary conditions, obtaining the geometric parameters of the 12-sided polygon, the parameters of the TMD device, and the layout of the 24 viscous dampers;

[0092] The design module is used to design the aeroelastic instability prevention and control of the upper cylindrical section based on the vibration control results of the middle multi-faceted transition section, and obtain the number of slices, trapezoidal longitudinal rib configuration, and layered pre-tension distribution of the multi-slice cylindrical structure;

[0093] The coordination module is used to integrate the dynamic characteristics of the three-segment structure into a coordinated process to obtain the frequency avoidance matrix of the entire tower and the impedance matching parameters of the inter-segment connections;

[0094] The verification module is used to perform multi-condition coupling verification on the three-section combined structure design scheme through the large eddy simulation-finite element coupling verification algorithm to obtain the target design parameters.

[0095] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A design method for a three-section combined structure of an ultra-high wind power tower, characterized in that: The method comprises: A multi-physics collaborative analysis of the wind speed distribution data of the target wind farm was performed using a wind load-structural dynamics-material mechanics coupling algorithm to obtain the stiffness distribution function and frequency avoidance constraints of the three functional partitions. A multi-objective optimization process was performed on the geometric parameters of the lower truss segment based on the stiffness distribution function, resulting in the optimal configuration of the diagonal brace crossing angle, main diagonal tube specifications, and steel cable-concrete composite cross-section. Taking the dynamic characteristics of the lower truss section as boundary conditions, the fluid-structure interaction vibration control design of the middle polygonal transition section was carried out, and the geometric parameters of the 12-sided polygon, the parameters of the TMD device, and the layout of 24 viscous dampers were obtained. Based on the vibration control results of the middle polygonal transition section, the upper cylindrical section was designed to prevent and control aeroelastic instability, and the number of slices, trapezoidal longitudinal rib configuration, and layered pre-tension distribution of the multi-slice cylindrical structure were obtained. The dynamic characteristics of the three-segment structure are integrated and coordinated to obtain the frequency avoidance matrix of the entire tower and the impedance matching parameters of the inter-segment connections. The three-section combined structure design scheme was verified by multi-working condition coupling through large eddy simulation-finite element coupling verification algorithm to obtain the target design parameters.

2. The method for designing a three-section combined structure of an ultra-high wind power tower according to claim 1, characterized in that: The wind speed distribution data of the target wind farm is subjected to a multi-physics collaborative analysis using a wind load-structural dynamics-material mechanics coupling algorithm to obtain stiffness distribution functions and frequency avoidance constraints for the three functional partitions, including: Obtain wind speed distribution data within the target wind farm's height range of 60 to 700 meters, calculate the wind load field using the wind speed gradient function, and obtain the wind load distribution characteristics at different height segments; The wind load distribution characteristics are input into the structural dynamics model for coupled solution to obtain the displacement response and stress distribution of each height segment; The stiffness distribution function is constructed segmentally and continuously based on the displacement response, and the gradient distribution of the stiffness coefficient of the 0-120m segment, the 120-200m segment, and the 200-360m segment is obtained; Frequency avoidance constraints are established according to the impeller passing frequency of 0.15-0.2 Hz to perform resonance avoidance calculation, and the avoidance matrix and safe frequency bandwidth parameters of the first three frequencies are obtained.

3. The design method of the three-section combined structure of the ultra-high wind power tower according to claim 1 is characterized in that: The multi-objective optimization process of the geometric parameters of the lower truss section based on the stiffness distribution function is performed to obtain the optimal configuration of the diagonal brace crossing angle, the main diagonal tube specifications and the steel wire rope-concrete composite section, including: Inputting the stiffness distribution function into a multi-objective optimization model to solve the truss geometric parameters, thereby obtaining the main oblique tube diameter range, wall thickness range, oblique brace angle range, and chord diameter range; Based on the principle of minimizing the drag coefficient, the angle range of the diagonal brace is optimized and calculated to obtain a diagonal brace crossing angle of 50 degrees plus or minus 5 degrees and a corresponding drag coefficient; The wire rope pre-tension is optimized according to the objective of maximizing the equivalent stiffness of the composite section, and the wire rope specification parameters and pre-tension values ​​corresponding to the main inclined tube specifications are obtained; The diameter range of the main inclined tube, the crossing angle of the diagonal brace and the specification parameters of the steel wire rope are input into the C50 concrete casting process to construct a composite section, thereby obtaining an optimized configuration of the steel wire rope-concrete composite section.

4. The method for designing a three-section combined structure of an ultra-high wind power tower according to claim 1, characterized in that: The dynamic characteristics of the lower truss section are used as boundary conditions to perform fluid-structure coupling vibration control design on the middle polygonal transition section, and the geometric parameters of the 12-sided polygon, the TMD device parameters, and the arrangement scheme of 24 viscous dampers are obtained, including: The dynamic characteristics of the lower truss section are input into the fluid-structure coupling control model to calculate the flow around the polygon, and the Strouhal number and vortex shedding frequency of the 12-sided polygon are obtained; Based on the vortex shedding frequency, the polygonal geometric shape is subjected to an arc-shaped processing to obtain arc radius parameters and surface pressure coefficient gradient geometric parameters of the 12-sided polygonal shape; The mass-stiffness-damping collaborative design of the TMD system was performed based on the geometric parameters of the 12-sided polygon, and the TMD device parameters with a mass ratio of 0.02, a frequency ratio of 0.95, and a damping ratio of 0.1 were obtained; The TMD device parameters were used as constraints to optimize the position of the viscous dampers, and an arrangement scheme of 24 viscous dampers with a damping coefficient of 2000 kN / m and a velocity index of 0.3 was obtained.

5. The method for designing a three-section combined structure of an ultra-high wind power tower according to claim 1, characterized in that: Based on the vibration control results of the middle polygonal transition section, the upper cylindrical section is designed for aeroelastic instability prevention and control, and the number of slices, trapezoidal longitudinal rib configuration, and layered pre-tension distribution of the multi-slice cylindrical structure are obtained, including: The vibration control results of the middle polygonal transition section are input into the aeroelastic stability discrimination model to solve the eigenvalues, and the lift coefficient, drag coefficient and aerodynamic derivative are obtained; Based on the aerodynamic derivatives, the Reynolds number correlation optimization of the number of cylindrical segments is performed to obtain a distribution of the number of segments of a multi-slice cylindrical structure with 18 segments for 200-280 meters, 12 segments for 280-320 meters, and 6 segments for 320-360 meters; Performing aerodynamic drag reduction design on the trapezoidal longitudinal ribs based on the number distribution, a trapezoidal longitudinal rib configuration with a rib height of 200-800 mm, a rib width ratio of 0.6, and a rib spacing of 600 mm was obtained; The trapezoidal longitudinal rib configuration is input into the geometric stiffness matrix to perform pretension optimization calculation, and the pretension gradient values ​​of 150 kN for the bottom layer, 120 kN for the middle layer, and 90 kN for the top layer are obtained; The steel wire rope is designed for layered arrangement based on the pre-tension gradient value, and a layered pre-tension distribution is obtained with the first layer at 0 degrees, 120 degrees, and 240 degrees and the second layer at 60 degrees, 180 degrees, and 300 degrees.

6. The method for designing a three-section combined structure of an ultra-high wind power tower according to claim 1, characterized in that: The dynamic characteristics of the three-segment structure are subjected to integrated dynamic coordination processing to obtain the full-tower frequency avoidance matrix and the impedance matching parameters of the inter-segment connections, including: The dynamic characteristics of the lower truss section, the middle polygonal transition section and the upper cylindrical section are input into a segmented coupled dynamic model for integrated modeling to obtain the mass matrix, damping matrix and stiffness matrix of the entire tower; Based on the mass matrix, damping matrix and stiffness matrix of the whole tower, the frequency ratio of adjacent segments is coordinated and calculated to obtain a frequency ratio range of 0.7-1.3 and a modal vibration shape continuity constraint condition; A frequency avoidance matrix is ​​established based on the frequency ratio range and continuity constraint conditions to perform resonance avoidance design, and a full-tower frequency avoidance matrix is ​​obtained with the first three frequencies being 0.12 Hz, 0.31 Hz, and 0.58 Hz, respectively. The full-tower frequency avoidance matrix is ​​used as a constraint condition to optimize the impedance matching of the inter-segment connections, and impedance matching parameters of the inter-segment connections with smooth transmission of vibration energy and a stress concentration factor less than 1.5 are obtained.

7. The method for designing a three-section combined structure of an ultra-high wind power tower according to claim 1, characterized in that: The three-section combined structure design scheme is verified by multi-working condition coupling through the large eddy simulation-finite element coupling verification algorithm to obtain the target design parameters, including: The three-section combined structure design was input into the large eddy simulation numerical test platform for flow field modeling, and a computational domain grid with a diameter of 15 times in the upwind direction, 30 times in the leeward direction, and 10 times in the lateral direction was obtained. Based on the computational domain grid, multiple working condition combinations are performed for wind speeds of 3-25 meters per second, turbulence intensity of 5%-25%, and wind direction angles of 0-180 degrees to obtain a coupling verification matrix of 525 verification working conditions; The coupling verification matrix is ​​input into the fluid-structure coupling algorithm to perform time domain response calculation, and verification results are obtained that the maximum displacement is less than 1 / 116 of the tower height, the maximum stress is less than 254 MPa, and the fatigue damage degree is less than 0.5; Based on the verification results, the design parameters were finally confirmed and optimized to obtain the target design parameters that meet the 360-meter super-height requirement and the 25-year design life.

8. The method for designing a three-section combined structure of an ultra-high wind power tower according to claim 1, characterized in that: The middle polygonal transition section and the upper cylindrical section are mainly designed as keel reinforcement points, and the keel structure is a trapezoidal area with a clever combination of longitudinal flanges.

9. The method for designing a three-section combined structure of an ultra-high wind power tower according to claim 1, characterized in that: Inner annular flanges are installed every 4 meters in the middle polygonal transition section and the upper cylindrical section, and the structure is adjustable by tightening the wire rope.

10. A three-section combined structure design system for an ultra-high wind power tower, characterized in that: The method for designing a three-section combined structure of an ultra-high wind power generation tower according to any one of claims 1 to 9 is used to implement the three-section combined structure design method of an ultra-high wind power generation tower according to any one of claims 1 to 9, wherein the three-section combined structure design system of the ultra-high wind power generation tower comprises: The analysis module is used to perform multi-physics collaborative analysis on the wind speed distribution data of the target wind farm using a wind load-structural dynamics-material mechanics coupling algorithm to obtain the stiffness distribution function and frequency avoidance constraints of the three functional partitions; The optimization module is used to perform multi-objective optimization on the geometric parameters of the lower truss segment based on the stiffness distribution function, and obtain the optimal configuration of the diagonal brace crossing angle, main diagonal tube specifications, and wire rope-concrete composite cross section; The control module is used to design the fluid-structure interaction vibration control of the middle polygonal transition section using the dynamic characteristics of the lower truss section as boundary conditions, obtaining the geometric parameters of the 12-sided polygon, the parameters of the TMD device, and the layout of the 24 viscous dampers; The design module is used to design the aeroelastic instability prevention and control of the upper cylindrical section based on the vibration control results of the middle multi-faceted transition section, and obtain the number of slices, trapezoidal longitudinal rib configuration, and layered pre-tension distribution of the multi-slice cylindrical structure; The coordination module is used to integrate the dynamic characteristics of the three-segment structure into a coordinated process to obtain the frequency avoidance matrix of the entire tower and the impedance matching parameters of the inter-segment connections; The verification module is used to perform multi-condition coupling verification on the three-section combined structure design scheme through the large eddy simulation-finite element coupling verification algorithm to obtain the target design parameters.

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