Wind power mixed tower door opening design method and system

Abstract

The invention provides a wind power mixed tower door opening design method and system, and relates to the technical field of wind power tower design. According to the method, the optimal forming position of a door opening in a tower drum is determined according to the operation condition of the wind generating set, and the position and range of a key area are determined by defining the initial geometrical shape and initial reinforcement parameters of the door opening; equivalent stress of all nodes in the key area is obtained through dynamic load simulation analysis, and the position corresponding to the maximum equivalent stress is determined according to distribution; a measuring point is selected on the outer surface of the cylinder wall in the normal direction of the door opening curve at the maximum equivalent stress point, and an equivalent stress value corresponding to the measuring point is obtained; welding hot spot stress serving as a stress concentration coefficient is calculated according to an equivalent stress value, and geometric shapes and reinforcement parameters are optimized through a genetic algorithm, so that structural stress concentration can be relieved, stability and durability under a dynamic working condition can be improved, construction cost can be saved, material waste can be reduced, and the influence of a door opening on the overall performance of the tower drum is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wind power tower design, and particularly relates to a wind power mixed tower door opening design method and system. BACKGROUND

[0002] With the rapid development of wind power technology, the wind power mixed tower structure has become an important research direction in the field of wind power engineering due to its significant advantages in reducing construction cost and improving power generation efficiency. However, the current wind power mixed tower door opening setting and reinforcement design scheme still has some technical defects in safety, economy and the like, which directly affects the overall performance and engineering economy of the wind power mixed tower structure.

[0003] The door opening design in the prior art is mainly based on static mechanical performance optimization, and the safety requirements of the wind turbine under dynamic operating conditions, especially the structural reliability under extreme wind load conditions, are not fully considered. At the same time, the existing door frame reinforcement design requirement is too high, which not only increases the construction cost and technical difficulty, but also may lead to unreasonable structural layout due to the lack of systematic optimization of the door opening position, thereby affecting the overall safety performance and economic indicators.

[0004] Engineering practice and research show that the current wind power mixed tower door opening design method has obvious deficiencies in many key performance indicators. Under dynamic operating conditions, especially under strong wind, earthquake and other extreme loads, the existing door opening arrangement scheme is prone to cause uneven stress distribution of the structure, and obvious stress concentration phenomenon appears in the door opening peripheral area, which not only endangers the overall stability of the structure, but also accelerates the structural damage due to repeated bearing of abnormal stress. In addition, the current reinforcement design method is too complex, which not only increases the construction technical difficulty, but also significantly increases the material cost and labor cost, thereby reducing the engineering economic feasibility. SUMMARY

[0005] The present application aims to provide a wind power mixed tower door opening design method and system to alleviate the technical problems of insufficient stability and durability of the wind power mixed tower door opening design in the prior art under dynamic operating conditions, which leads to the weakening of the door opening to the overall performance of the tower.

[0006] In a first aspect, the present application provides a wind power mixed tower door opening design method, comprising the following steps: determining the optimal opening position of the door opening on the tower according to the operating conditions of the wind turbine; defining the initial geometric shape and initial reinforcement parameters of the door opening, and determining the position and range of the key area, wherein the key area is an annular area on the tower extending inward from the edge of the door opening to a range of 3 times the tower wall thickness; A finite element model is established for the doorway and its key area, and dynamic load simulation analysis is performed to obtain the equivalent stress distribution of all nodes in the key area. Based on the equivalent stress distribution, the location corresponding to the maximum equivalent stress is determined. Along the normal direction of the curve of the doorway at the point corresponding to the maximum equivalent stress, select a measurement point on the outer surface of the cylinder wall and obtain its corresponding equivalent stress value; The welding hot spot stress is calculated based on the measurement points and their corresponding equivalent stress values, and the welding hot spot stress is used as the stress concentration factor. With the goal of minimizing the stress concentration factor, the optimal geometric curve shape that conforms to wind power design specifications is obtained iteratively. By approximating the optimal geometric curve shape using multiple circular arcs, a practically optimized curve shape that can be used for engineering implementation is generated.

[0007] In conjunction with the first aspect, the present invention provides a first possible implementation of the first aspect, wherein calculating the welding hot spot stress based on the measurement point and its corresponding equivalent stress value includes: Using the formula: Calculate the stress at the welding hotspot; among which, and These are the equivalent stresses at positions 0.3t and 1.2t, obtained through dynamic load simulation calculations. The 0.3t position is located on the outer surface of the cylinder wall, along the curve of the portal, at a distance of 0.3 times the cylinder wall thickness from the edge of the portal at the point corresponding to the maximum equivalent stress. The 1.2t position is located on the outer surface of the cylinder wall, along the curve of the portal, at a distance of 1.2 times the cylinder wall thickness from the edge of the portal at the point corresponding to the maximum equivalent stress.

[0008] In conjunction with the first aspect, the present invention provides a second possible implementation of the first aspect, wherein when using multiple circular arcs to approximate the optimal geometric curve shape, five circular arcs are used for approximation.

[0009] In conjunction with the first aspect, the present invention provides a third possible implementation of the first aspect, wherein when using multiple circular arcs to approximate the optimal geometric curve shape, four or six circular arcs are used for approximation.

[0010] In conjunction with the first aspect, the present invention provides a fourth possible implementation of the first aspect, wherein the initial geometry comprises: two straight line segments and a curved segment connecting the two straight line segments, the curved segment forming a transition area at the top of the doorway.

[0011] In conjunction with the first aspect, the present invention provides a fifth possible implementation of the first aspect, wherein, based on the actual optimized curve shape, the reinforcement parameters of the door opening are further adjusted so that the final stress concentration factor reaches a minimum value, wherein the reinforcement parameters include: the diameter of the main reinforcement bars and the spacing of the stirrups in the curved segment of the door opening.

[0012] In conjunction with the fifth possible implementation of the first aspect, the present invention provides a sixth possible implementation of the first aspect, wherein the diameter of the main reinforcement is 0.9 to 1.1 times the thickness of the tower wall, and the spacing of the stirrups is 2 to 3 times the diameter of the main reinforcement.

[0013] In conjunction with the fifth possible implementation of the first aspect, the present invention provides a seventh possible implementation of the first aspect, wherein the reinforcement parameters further include: the number of main reinforcement bars N1 at the center height of the door opening, wherein N1 / W = 0.8 to 1.2, and W is the number of reinforcement bars on one side of the door opening.

[0014] In conjunction with the seventh possible implementation of the first aspect, the present invention provides an eighth possible implementation of the first aspect, wherein the reinforcement parameters further include the number of main reinforcement bars at the upper end of the door opening; Among them, the number of main reinforcement bars at the center height of the doorway is greater than the number of main reinforcement bars at the top of the doorway.

[0015] Secondly, the wind power hybrid tower portal design system provided by the present invention includes a memory and a processor. The memory stores a computer program that can run on the processor. When the processor executes the computer program, it implements the wind power hybrid tower portal design method described in the first aspect.

[0016] The embodiments of this invention bring the following beneficial effects: The optimal location of the portal opening on the tower is determined based on the operating conditions of the wind turbine generator set; the initial geometry and initial reinforcement parameters of the portal opening are defined; and the location and range of the key area are determined. The key area is a ring-shaped region on the tower extending inward from the edge of the portal opening to a range of three times the tower wall thickness. A finite element model is established for the portal opening and its key area, and dynamic load simulation analysis is performed to obtain the equivalent stress distribution of all nodes within the key area. Based on this equivalent stress distribution, the location corresponding to the maximum equivalent stress is determined along the normal direction of the portal opening curve at the point corresponding to the maximum equivalent stress. Measurement points are selected on the outer surface of the tower wall, and their corresponding equivalent stress values ​​are obtained. The welding hot spot stress is calculated based on the measurement points and their corresponding equivalent stress values, and the welding hot spot stress is used as the stress concentration factor. With the goal of minimizing the stress concentration factor, the optimal geometric curve shape that conforms to the wind power design specifications is obtained iteratively. The optimal geometric curve shape is approximated by multiple circular arcs to generate an actual optimized curve shape that can be used for engineering implementation. This can reduce the structural stress concentration factor, improve its stability and durability under dynamic working conditions, improve the impact of the portal opening on the overall performance of the tower, and at the same time help save construction costs and reduce material waste.

[0017] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the specific embodiments or related technologies of the present invention, the drawings used in the description of the specific embodiments or related technologies 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 from these drawings without creative effort.

[0019] Figure 1 A schematic flowchart illustrating the wind power hybrid tower portal design method provided in an embodiment of the present invention; Figure 2 A schematic diagram of the wind power hybrid tower entrance provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the reinforcement layout of the wind power hybrid tower portal provided in an embodiment of the present invention; Figure 4 A schematic diagram of the initial geometry in the wind power hybrid tower portal design method provided in an embodiment of the present invention; Figure 5 The equivalent stress distribution diagram of the wind turbine hybrid tower portal before optimization; Figure 6 The equivalent stress distribution diagram is shown in the simulation analysis of the portal opening of the optimized wind turbine hybrid tower.

[0020] Icons: 1-Straight line segment; 2-Curved segment; 3-Door opening; 4-Stirrup; 5-Main reinforcement. Detailed Implementation

[0021] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used only to describe differences in name and should not be construed as indicating or implying relative importance. Physical quantities in formulas, unless otherwise specified, should be understood as basic quantities in the International System of Units (SI), or derived quantities derived from basic quantities through mathematical operations such as multiplication, division, differentiation, or integration.

[0023] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0024] like Figure 1 , Figure 2 and Figure 3 As shown in the figure, the wind power hybrid tower portal design method in this embodiment of the invention includes the following steps: The optimal location for opening the portal 3 on the tower is determined based on the actual operating conditions of the wind turbine generator set (including extreme wind loads, normal operating vibrations, seismic loads, etc.). Define the initial geometry and initial reinforcement parameters of doorway 3, and clarify the location and extent of key areas; A high-precision finite element model was established for doorway 3 and its key area, and the model data was converted into a CAD format suitable for dynamic simulation analysis. Dynamic load simulation analysis was performed under extreme wind load conditions to obtain the equivalent stress distribution of all nodes in the key area; Determine the location corresponding to the maximum equivalent stress, select a reference measurement point along its normal direction, and calculate the welding hot spot stress as the stress concentration factor; Using the minimization of stress concentration factor as the objective function, an intelligent optimization algorithm is used to iteratively adjust the coordinates of the control points of the portal 3 outline to obtain the optimal geometric curve shape that conforms to international wind power design specifications. The optimal curve is approximated using multiple circular arcs to generate an optimized curve shape that can be used in actual processing and manufacturing. Based on the optimized geometry, the reinforcement layout parameters of the doorway 3 area were further adjusted to minimize the stress concentration of the final structure.

[0025] The above process can be integrated into an automated design platform to achieve closed-loop optimization of the entire process from input to output.

[0026] See Figure 2 , Figure 3 and Figure 4 In this embodiment, the initial geometry of the doorway 3 consists of two vertical straight line segments 1 and a curved segment 2 connecting their tops, forming an approximately rectangular transitional structure with a dome. The curved segment 2 serves to mitigate the stress transmission path and is a key component affecting the degree of stress concentration.

[0027] Reinforcement parameters include, but are not limited to: diameter D1 of main reinforcement 5 in curved segment 2, spacing S1 of stirrups 4, number N1 of main reinforcement 5 at the center height of doorway 3, and number N2 of main reinforcement 5 at the top of doorway 3. All of these parameters can be initially designed based on experience in concrete tower construction and will be dynamically adjusted during subsequent optimization processes.

[0028] In this embodiment, based on structural mechanics analysis, the local stress gradient near the edge of the doorway 3 increases significantly. Therefore, the key region is defined as a ring-shaped area extending from the edge of the doorway 3 towards the inner side of the tower to a range of 3 times the tower wall thickness (i.e., 3t). The material stress state within this region is complex and prone to fatigue damage, requiring focused modeling and analysis.

[0029] See Figure 2 , Figure 5 and Figure 6Finite element modeling and dynamic load simulation: Using professional CAE software (such as ANSYS), a three-dimensional solid finite element model containing doorway 3 and its key areas was constructed. The model was discretized using eight-node hexahedral elements, and local mesh refinement was implemented near the edges of doorway 3 to ensure the accuracy of stress field capture. The modeling data was exported as STEP or IGES format CAD files and imported into the dynamic simulation environment. Typical extreme load spectra were applied, including: lateral shear force and bending moment caused by extreme gusts, the weight of the tower itself and the weight of internal equipment, seismic response loads (for projects in high-intensity seismic zones), and periodic dynamic load excitation during operation. Through transient dynamic simulation, the equivalent stress time history of each node in the entire key area during the loading process was obtained, and the equivalent stress distribution cloud map at the peak moment was extracted.

[0030] In the equivalent stress distribution results, the spatial location point P corresponding to the maximum equivalent stress value in the entire critical area is identified. A normal direction line L is drawn through this point to the boundary curve of the portal 3. Three specific reference points are located along the L direction on the outer surface of the cylinder wall: Let the equivalent stress at point A, located 0.3t from the edge of the doorway, be denoted as . ; Let the equivalent stress at point B, located 1.2t from the edge of the doorway 3, be denoted as . ; The third point is usually taken at the middle position of 0.75t, which is used to verify the stability of the interpolation.

[0031] An improved hot spot stress interpolation formula is adopted. Calculate the stress at the welding hot spot, where, and These are the equivalent stresses at positions 0.3t and 1.2t, obtained through dynamic load simulation calculations. The 0.3t position is located on the outer surface of the cylinder wall, along the curve of portal 3, at a distance of 0.3 times the cylinder wall thickness from the edge of portal 3 along the normal direction of the point corresponding to the maximum equivalent stress. The 1.2t position is located on the outer surface of the cylinder wall, along the curve of portal 3, at a distance of 1.2 times the cylinder wall thickness from the edge of portal 3 along the normal direction of the point corresponding to the maximum equivalent stress. Coefficients 1.5 and 0.5 are correction coefficients in the interpolation formula, empirical correction factors obtained through regression calibration of a large amount of simulation data. These factors can more accurately reflect the stress amplification effect at the root of the actual weld, and have higher prediction accuracy compared to the traditional linear extrapolation method.

[0032] Geometric optimization process: A parametric model is established using the coordinates of several control points on the curve segment of doorway 3 as design variables. With the goal of minimizing the stress concentration factor, constraints are set to meet the following requirements: the net size of doorway 3 meets the passage requirements of maintenance personnel (generally ≥400 mm); the curvature is continuous and there are no sharp corner abrupt changes; and it complies with the demolding process limitations of precast concrete components. A genetic algorithm (GA) or other heuristic optimization strategies (such as particle swarm optimization, PSO) are used to drive iterative finite element simulation to search for the optimal doorway 3 profile curve that minimizes the stress concentration factor. After fine iteration, a smooth, irregular but mechanically superior optimal geometric curve shape is obtained.

[0033] Although the optimal curve has excellent vibration reduction and stress reduction effects, it may be a free curve, which is not conducive to factory mold making and rebar binding construction. Therefore, this invention proposes to use a multi-segment circular arc fitting method to transform it into an approximate curve that is feasible for engineering.

[0034] In a preferred embodiment, the optimal curve is approximated piecewise using five circular arcs. The start point, end point, and radius of curvature of each arc are determined by least squares fitting to ensure that the overall profile deviation is controlled within ±2mm.

[0035] In addition, four or six or more arcs can be flexibly selected for approximation according to manufacturing precision requirements, balancing processing costs and performance retention.

[0036] The final generated actual optimized curve retains the main stress reduction characteristics of the original optimized curve while also possessing good manufacturability. Simulation analysis shows its equivalent stress distribution diagram as follows: Figure 6 As shown, the optimization alleviated the stress concentration problem at the portal opening of the wind turbine hybrid tower and reduced the structural stress concentration factor.

[0037] Based on the completed geometric optimization, the reinforcement configuration in the portal area 3 is further refined to achieve synergistic optimization of the entire system. Specific measures include: adjusting the diameter D1 of the main reinforcement 5 in the curved section, preferably 0.9 to 1.1 times the tower wall thickness; setting the stirrup spacing S1, preferably 2 to 3 times the diameter D1 of the main reinforcement 5; configuring the number of main reinforcement 5, wherein the number N1 of main reinforcement 5 at the center height of portal 3 is approximately 0.8 to 1.2 times the number W of reinforcement on one side of portal 3. A gradient reinforcement strategy is implemented: N1 > N2, and the number N1 of main reinforcement 5 at the center height of portal 3 is slightly larger than the number N2 of main reinforcement 5 at the upper end of portal 3, effectively addressing the problem of uneven bending moment distribution. In one embodiment, with a tower wall thickness of 70mm, the width of portal 3 is 450mm, the number N2 of main reinforcement 5 at the upper end of portal 3 is 6, the diameter D1 of main reinforcement 5 is 65mm, and the stirrup spacing S1 is 150mm.

[0038] This invention also provides a wind turbine hybrid tower portal design system, including a processor, a memory, and a computer program stored in the memory and executable on the processor. When the processor executes the program, it implements the method steps of any of the above embodiments.

[0039] The system can be deployed on a local workstation or cloud server, supports data interaction with other BIM / CAD / CAE platforms, and has functions such as automated modeling, batch simulation, and result visualization, which significantly improves design efficiency and reliability.

[0040] The wind turbine hybrid tower portal design method and system described in the above embodiments propose a complete wind turbine hybrid tower portal design solution through a combination of geometric optimization, reinforcement coordination, numerical simulation, and intelligent algorithms. This solution not only significantly reduces the risk of stress concentration and improves structural durability, but also ensures the feasibility of industrial production through a multi-segment circular arc approximation strategy, combining safety, economy, and scalability.

[0041] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; 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 or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for designing the portal opening of a wind turbine hybrid tower, characterized in that, Includes the following steps: The optimal location for the portal on the tower should be determined based on the operating conditions of the wind turbine generator set. Define the initial geometry and initial reinforcement parameters of the doorway, and determine the location and extent of the critical area, wherein the critical area is a ring-shaped area on the tower extending inward from the edge of the doorway to a range of 3 times the tower wall thickness; A finite element model is established for the doorway and its key area, and dynamic load simulation analysis is performed to obtain the equivalent stress distribution of all nodes in the key area. Based on the equivalent stress distribution, the location corresponding to the maximum equivalent stress is determined. Along the normal direction of the curve of the doorway at the point corresponding to the maximum equivalent stress, select a measurement point on the outer surface of the cylinder wall and obtain its corresponding equivalent stress value; The welding hot spot stress is calculated based on the measurement points and their corresponding equivalent stress values, and the welding hot spot stress is used as the stress concentration factor. With the goal of minimizing the stress concentration factor, the optimal geometric curve shape that conforms to wind power design specifications is obtained iteratively. By approximating the optimal geometric curve shape using multiple circular arcs, a practically optimized curve shape that can be used for engineering implementation is generated.

2. The wind power hybrid tower portal design method according to claim 1, characterized in that, The calculation of welding hot spot stress based on the measurement points and their corresponding equivalent stress values ​​includes: Using the formula: Calculate the stress at the welding hotspot; among which, and These are the equivalent stresses at positions 0.3t and 1.2t, obtained through dynamic load simulation calculations. The 0.3t position is located on the outer surface of the cylinder wall, along the curve of the portal, at a distance of 0.3 times the cylinder wall thickness from the edge of the portal at the point corresponding to the maximum equivalent stress. The 1.2t position is located on the outer surface of the cylinder wall, along the curve of the portal, at a distance of 1.2 times the cylinder wall thickness from the edge of the portal at the point corresponding to the maximum equivalent stress.

3. The wind power hybrid tower portal design method according to claim 1, characterized in that, When using multiple arc segments to approximate the optimal geometric curve shape, five arc segments are used for approximation.

4. The wind power hybrid tower portal design method according to claim 1, characterized in that, When using multiple arc segments to approximate the optimal geometric curve shape, four or six arc segments are used for approximation.

5. The wind power hybrid tower portal design method according to any one of claims 1 to 4, characterized in that, The initial geometry includes two straight line segments and a curved segment connecting the two straight line segments, the curved segment forming a transition area at the top of the doorway.

6. The wind power hybrid tower portal design method according to claim 1, characterized in that, Also includes: Based on the actual optimized curve shape, the reinforcement parameters of the doorway are further adjusted to minimize the final stress concentration factor. The reinforcement parameters include the diameter of the main reinforcement bars and the spacing of the stirrups in the curved section of the doorway.

7. The wind power hybrid tower portal design method according to claim 6, characterized in that, The diameter of the main reinforcement bar is 0.9 to 1.1 times the thickness of the tower wall, and the spacing of the stirrups is 2 to 3 times the diameter of the main reinforcement bar.

8. The wind power hybrid tower portal design method according to claim 6, characterized in that, The reinforcement parameters also include: the number of main reinforcement bars N1 at the center height of the doorway, where N1 / W = 0.8 to 1.2, and W is the number of reinforcement bars on one side of the doorway.

9. The wind power hybrid tower portal design method according to claim 8, characterized in that, The reinforcement parameters also include the number of main reinforcement bars at the top of the doorway; Among them, the number of main reinforcement bars at the center height of the doorway is greater than the number of main reinforcement bars at the top of the doorway.

10. A wind turbine hybrid tower portal design system, characterized in that, The device includes a memory and a processor, wherein the memory stores a computer program that can run on the processor, and the processor executes the computer program to implement the wind power hybrid tower portal design method according to any one of claims 1 to 9.

Images