Steel pipe spanning frame mechanical analysis method considering semi-rigid joints

Abstract

The invention relates to a steel pipe crossing frame mechanical analysis method considering semi-rigid joints, and belongs to the technical field of electric power engineering construction. The method comprises the following steps: constructing a finite element model, replacing a connection node with a semi-rigid node, calculating a load, setting a boundary condition, applying the load, and finally exporting mechanical property data. The method also comprises a verification step: adjusting parameters through comparison with experimental data, and ensuring that the model precision error is less than 5%. In addition, the model construction form can be changed, and the influence rule of different construction forms on the mechanical property is analyzed. The precision and efficiency of mechanical analysis of the steel pipe crossing frame are improved, a scientific basis is provided for power transmission line construction, and the method has important engineering application value.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electric power engineering construction, in particular to a steel pipe crossing frame mechanical analysis method considering semi-rigid nodes. BACKGROUND

[0002] Overhead transmission line is an important part of the power system, with the increasing scale of the power system, high-voltage long-distance transmission lines are increasing. In the conductor erection of newly-built transmission lines, with the increase of voltage level, more and more existing power lines, railways, highways, lakes, economic crop areas and other obstacles need to be crossed by newly-built extra-high voltage transmission lines. The dependence of modern industry on electricity makes it more and more difficult to stop power operation, especially the power operation of high-grade lines, which will seriously affect the construction progress and construction cost, and will also cause certain losses to social life and production. Steel pipe crossing frame, as an important equipment in transmission line engineering, is widely used in live crossing operation due to its high strength, diversity, easy installation, lightness and suitability for various terrains. The steel pipe crossing frame is a supporting structure connected by fasteners, and the right-angle fastener is used to connect the vertical rod and the horizontal rod. In practical application, the components connected by the right-angle fastener always have different degrees of relative rotation, that is, the connection stiffness between the components is limited, so the component connection of the steel pipe crossing frame is semi-rigid connection between rigid connection and hinged connection. The performance of the node has a great influence on the overall performance of the steel pipe crossing frame structure, and once the node is damaged, it will cause damage to multiple components connected thereto, which has a greater impact on the structure than the damage of a single component. Therefore, in order to ensure the safety of the transmission line engineering, it is necessary to study the mechanical properties of the steel pipe crossing frame considering the semi-rigid nodes, and obtain the mechanical response law under the action of wind load, dead load and impact load. However, there is no mature method for analyzing the mechanical properties of the steel pipe crossing frame structure at present. Most of the existing methods are calculated according to empirical formula, which has low calculation efficiency and accuracy, and cannot obtain the mechanical property distribution law of the overall structure of the steel pipe crossing frame. Moreover, the existing methods do not consider the influence of semi-rigid nodes on the mechanical properties of the steel pipe crossing frame, which may cause a large deviation between the analysis results and the actual situation, thereby affecting the safety and reliability of the transmission line construction. SUMMARY

[0003] The purpose of the present application is to provide a steel pipe crossing frame mechanical analysis method considering semi-rigid nodes, which can overcome the shortcomings of the prior art and provide an efficient and accurate steel pipe crossing frame mechanical property analysis method to provide a scientific basis for transmission line construction.

[0004] In order to solve the above problems, the technical scheme of the present application is as follows: A steel pipe crossing frame mechanical analysis method considering semi-rigid nodes, comprising the following steps: S1: constructing a finite element model of the steel pipe crossing frame structure according to a preset rule; S2: replacing the connecting nodes of the steel pipe crossing frame structure with semi-rigid nodes; S3: calculating the load borne by the steel pipe crossing frame structure model and converting it into the form of equivalent external force; S4: setting boundary conditions for the bottom nodes of the steel pipe crossing frame structure; S5: selecting all the nodes of the steel pipe crossing frame structure under stress, and loading the equivalent external force obtained to each node; S6: calculating and exporting the mechanical property data of the steel pipe crossing frame structure.

[0005] Further, the specific method of constructing the finite element model in S1 comprises: S1.1: obtaining the spatial geometric parameters of each member according to the actual design drawings of the steel pipe crossing frame structure, and establishing a point-line model; S1.2: simulating each member of the steel pipe crossing frame structure; S1.3: meshing the steel pipe crossing frame structure model. Further, the specific method of replacing the semi-rigid nodes in S2 comprises: S2.1: determining all the connecting nodes that need to be replaced; S2.2: selecting a semi-rigid node simulation method according to the mechanical properties of the semi-rigid node; S2.3: replacing each connecting node according to the selected simulation method; S2.4: using a loop command to replace the nodes in batches.

[0006] Further, the semi-rigid node simulation parameters include: the length of the rigid zone accounts for 5% to 15% of the length of the member, the spring stiffness is determined according to the experimental data of the node rotational stiffness, and the number of segmented intermediate beam elements is 3 to 5 segments.

[0007] Further, the load calculation in S3 includes vertical load calculation and wind load calculation: The vertical load calculation formula is:

[0008] wherein W j is the vertical load of the steel pipe crossing frame in the accident state; K1 is the impact coefficient, which is selected according to the height, and is 1.3 to 1.5; y is the vertical span of the crossing frame when the erected conductor falls on the crossing frame; m is the number of sub-conductors simultaneously laid out; and w is the unit length weight of a single conductor of the construction line; The wind load calculation formula is:

[0009] is the wind load of the steel pipe crossing frame structure frame body; is the wind vibration coefficient at height z; is the wind pressure height variation coefficient; is the overall shape coefficient of the steel pipe crossing frame; is the standard value of the reference wind pressure; is the area of the steel pipe crossing frame subjected to the wind pressure. Further, the boundary condition setting in S4 includes: fixed constraints are applied to all stand poles and the bottom nodes of the stay wire at the bottom end of the steel pipe crossing frame structure, and the displacement of these nodes is limited to 0. Further, in S5, the nodes are selected according to the geometric shape and stress condition of the structure, and all nodes on the windward surface of the steel pipe crossing frame structure and all nodes subjected to vertical load are selected.

[0010] Further, in S5, the calculated equivalent external force is applied to the selected nodes when the load is applied, and when the load is applied, it is necessary to ensure that the direction and size of the load are consistent with the actual situation.

[0011] Further, in S6, the solver of the finite element analysis software is used to solve the model, and in the solving process, the software calculates the stress distribution and displacement distribution of the structure according to the applied load and boundary conditions. Mechanical performance data.

[0012] Further, it also includes a verification step: comparing the calculation results with the experimental data, adjusting the semi-rigid node spring stiffness parameters, and ensuring that the model precision error is less than 5%.

[0013] The beneficial effects of the present application are: (1) The present application uses APDL language to analyze the finite element model of the steel pipe crossing frame structure, greatly reduces the steps of analyzing the strength and stability of the steel pipe crossing frame structure, improves the calculation efficiency, and is very suitable for such mechanical calculation containing multiple working conditions.

[0014] (2) The present application realizes the calculation of multiple steel pipe crossing frame structure stress working conditions through APDL language, checks the strength and stability of the steel pipe crossing frame structure, and can export the displacement and stress data of numerous steel pipe crossing frame structures in the form of cloud chart and table.

[0015] (3) The present application reduces code redundancy through macro files and calling scripts, and improves the execution efficiency of the program.

[0016] (4) The present application provides a complete APDL calculation program, which can be adaptively changed according to different steel pipe crossing frame models, and can realize the simulation of other loads and working conditions by adding commands, and has good general analysis ability. BRIEF DESCRIPTION OF DRAWINGS

[0017] The application will be further described below with reference to the drawings: Figure 1 is a whole flow chart of the method of the application; Figure 2 is a finite element model schematic diagram of a steel pipe span frame structure in the application; Figure 3 is a simulation schematic diagram of a semi-rigid joint in the application.

[0018] Figure 4 is a stress nephogram of a semi-rigid connected steel pipe span frame.

[0019] Figure 5 is a stress nephogram of a rigid connected steel pipe span frame. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the application will be clearly and completely described below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the application.

[0021] As shown in Figure 1 , a steel pipe span frame mechanical analysis method considering semi-rigid joints comprises the following steps: S1: constructing a finite element model of the steel pipe span frame structure according to a preset rule; in this embodiment, a finite element analysis method is used to construct a model of the steel pipe span frame structure. Finite element analysis is a method of approximately solving structural mechanics problems by dividing a complex structure into multiple small units, and is widely used in engineering structural analysis. Constructing a finite element model is the basis of the entire analysis process, and its accuracy directly affects the results of subsequent mechanical performance analysis: S1.1: according to the actual design drawings of the steel pipe span frame structure, obtaining the spatial geometric parameters of each member, including the length, position, angle and other parameter information of the member. Using these parameter information, a point-line model of the steel pipe span frame structure is established. The point-line model is the basis of the finite element model, which defines the geometric shape of the structure and the connection relationship of each member. For example, for a typical steel pipe span frame, the stand rod spacing is 2m, the cross rod step is 2m, and the row spacing is 3m. Through these parameters, the coordinates and connection relationship of each node can be defined one by one in the finite element analysis software; S1.2: Simulate each member of the steel pipe crossing frame structure. Select appropriate element types to simulate steel pipes and wires. For example, use beam elements (such as BEAM188) to simulate steel pipes, as beam elements can better reflect the mechanical behavior of steel pipes; use bar elements (such as LINK10) to simulate the stay wire, as bar elements are suitable for simulating slender stay wire structures. At the same time, the cross-sectional parameters and material properties of the members need to be defined, such as cross-sectional area, elastic modulus, Poisson's ratio, density, etc. For example, the elastic modulus of the steel pipe is 210 GPa, the Poisson's ratio is 0.3, and the density is 7850 kg / m³; the elastic modulus of the stay wire is 9.8 GPa, the Poisson's ratio is 0.3, and the density is 2700 kg / m³; The BEAM188 element is a high-order element in finite element software for simulating three-dimensional beam structures. It belongs to the 3D Timoshenko beam element, considering shear deformation, each node has 6 degrees of freedom, supports quadratic interpolation, can perform linear and nonlinear analysis, and can handle large deformation and stress stiffening effects. In terms of function, it can be compatible with multiple material models, define arbitrary shape cross-sections through specific commands, and simulate semi-rigid nodes, and bear multiple types of loads. Compared with the traditional BEAM4 element, BEAM188 considers shear deformation, supports more nonlinear cases, has more flexible cross-section definition, and has higher computational efficiency. In the analysis of steel pipe crossing frame, it can be used to simulate steel pipe members, model semi-rigid nodes, and analyze complex working conditions. Its parameter setting is flexible, it can open large deformation analysis function through specific command, and it can also define cross-section and assign material properties, with high precision, strong flexibility and high efficiency, which is an ideal choice for complex beam structure mechanics analysis.

[0022] LINK10 is a nonlinear element in finite element software for simulating one-dimensional rod / cable structures, mainly bearing axial tension and compression loads. It has 3 translational degrees of freedom per node, uses linear interpolation, supports large deformation and stress stiffening effects. It can be compatible with multiple material models, only transmit axial force, has no bending or torsional stiffness, also has special behavior of only tension or compression, and supports initial stress setting. Compared with the traditional LINK8 linear bar element, LINK10 supports large deformation, material nonlinearity, stress stiffening and initial stress setting, and is more suitable for cable, wire, cable and other structures. In the analysis of steel pipe crossing frame, it can be used to simulate the stay wire, and also can be combined with the beam element for contact analysis. This element has the advantages of high efficiency, strong pertinence and outstanding nonlinear capability, and is an ideal tool for simulating tension and compression structures such as transmission line wires and crossing frame stay wires.

[0023] S1.3: Mesh the steel pipe crossing frame structure model. It divides the structure into multiple small units for numerical calculation. When meshing, the balance between calculation accuracy and efficiency needs to be considered. For the stay cable, it can be divided into fewer units; for each rod, it can be divided into several units according to its length and complexity. For example, the stay cable can be divided into 1 unit, and each rod can be divided into 1 unit. Through reasonable meshing, the accuracy of the calculation results can be ensured, while avoiding too many calculation units leading to excessive calculation time.

[0024] S2: Replace the steel pipe crossing frame structure connection node with a semi-rigid node. The semi-rigid node model is shown in Figure 2. Figure 3 In actual steel pipe crossing frame structures, due to the presence of right-angle fasteners, the connection nodes are not completely rigid connections, but semi-rigid connections with certain rotational stiffness. Therefore, in order to more accurately simulate the actual mechanical behavior of the steel pipe crossing frame, it is necessary to replace the connection nodes in the finite element model with semi-rigid nodes. The specific process includes: S2.1: Determine all the connection nodes that need to be replaced. These nodes are usually the connection points between steel pipes and can be determined by checking the design drawings or the actual structure. For example, by selecting all BEAM188 elements, the numbers of these elements are obtained and stored in an array.

[0025] S2.2: According to the mechanical properties of the semi-rigid node, select an appropriate simulation method. This semi-rigid node simulation method simulates the local rigid constraint of the fastener by setting a rigid zone (length accounts for 5%~15% of the rod) at the node, quantifies the node rotational stiffness (stiffness value based on experimental data) by connecting spring elements (such as COMBIN14), and divides the rod into 3~5 middle beam elements (BEAM188) to achieve continuous distribution of stiffness, thereby truly reflecting the mechanical properties of the steel pipe crossing frame node between rigid and hinged connections. This method replaces the nodes in batches through APDL scripts, supports parameterized adjustment, and significantly improves the accuracy of structural analysis.

[0026] The reason why the length of the rigid zone accounts for 5%-15% of the length of the rod: In actual steel tube crossing frames, the connection part of the right-angle fastener is not completely flexible, but there is a certain rigid zone. Through a large number of actual engineering observations, mechanical experiments and numerical simulation studies, it is found that when the length of the rigid zone accounts for 5%-15% of the length of the rod, the local rigid constraint effect provided by the fastener at the node can be better simulated. From a microscopic perspective, the material properties, connection methods and other factors of the contact part of the fastener and the steel tube determine that it has a certain ability to resist relative rotation and displacement, and the size of this rigid zone will affect the overall mechanical behavior of the node. If the length of the rigid zone is too short, such as less than 5%, the rigid constraint effect of the fastener cannot be fully reflected, which will make the simulated node too flexible, resulting in excessive deformation and unreasonable stress distribution in the structural calculation; on the contrary, if the length of the rigid zone is too long, more than 15%, the node simulation will be too rigid, which will deviate greatly from the mechanical properties of the actual semi-rigid node, resulting in overestimation of the overall stiffness of the structure and unsafe calculation results.

[0027] The reason why the rod is divided into 3-5 middle beam elements: In the simulation of semi-rigid nodes, the rod is divided into 3-5 middle beam elements in order to balance the requirements of calculation accuracy, calculation efficiency and simulation of actual mechanical properties. On the one hand, too few division segments cannot accurately capture the stress and deformation near the node, resulting in large deviation in the calculation results and making it difficult to reflect the semi-rigid characteristics of the node, while 3-5 segments can effectively simulate the stress concentration of the node and the deformation of the rod, improving the calculation accuracy. On the other hand, too many division segments will greatly increase the calculation amount and calculation time, which does not meet the requirements of actual engineering for efficiency, and the setting of 3-5 segments can reasonably control the calculation amount while ensuring the accuracy, achieving a balance between the two. In addition, this division method can also better simulate the gradual change in stiffness of the semi-rigid node between rigid and hinged connections, which meets the needs of simulating the actual mechanical properties of the node and makes the simulation results more realistically reflect the mechanical behavior of the structure, providing reliable support for the overall mechanical performance analysis of the steel tube crossing frame.

[0028] S2.3: Replace each connection node according to the selected simulation method. During the replacement process, it is necessary to ensure that the mechanical properties of the new node are consistent with the semi-rigid node in the actual structure. For example, define the rigid zone ratio, spring stiffness, element division segment number and other parameters through the macro file. The length of the rigid zone accounts for 5%-15% of the length of the rod, the spring stiffness is determined according to the experimental data of the node rotational stiffness, and the middle beam element is divided into 3-5 segments; S2.4: Batch replace nodes using loop command. Through the loop command, all connection nodes can be automatically replaced with semi-rigid nodes without manual operation one by one. This greatly improves the efficiency of modeling and reduces the possibility of human error. At the same time, batch replacement of nodes also ensures the consistency and accuracy of the model.

[0029] S3: Calculate the load of the steel pipe crossing frame structure model according to the specification, and convert it into the form of equivalent external force before mechanical property analysis. Before mechanical property analysis, the various loads borne by the steel pipe crossing frame structure need to be calculated and converted into the form of equivalent external force for application in the finite element model: According to the specification, the equivalent static wind load value and vertical load of the steel pipe crossing frame structure are calculated; the vertical load value calculation formula of the steel pipe crossing frame structure is as follows:

[0030] In the formula: W j The vertical load of the steel pipe crossing frame in the accident state; K1 is the impact coefficient, which is selected according to the height, taking 1.3~1.5; l y The vertical span of the crossing frame when the erected conductor falls on the crossing frame; m is the number of sub-conductors simultaneously laid out; w is the unit length weight of the single conductor of the construction line.

[0031] The wind load value calculation formula of the steel pipe crossing frame structure is as follows:

[0032] The wind load of the steel pipe crossing frame structure; The wind vibration coefficient at height z; The wind pressure height variation coefficient; The overall shape coefficient of the steel pipe crossing frame; The standard value of the reference wind pressure; The area of the steel pipe crossing frame bearing wind pressure.

[0033] The specification includes “Safety Technical Code for Construction Fastener Steel Pipe Scaffolding” (JGJ 130), which is used for material strength and component stability calculation, and “Transmission Line Construction and Acceptance Specification”: for the design requirements of the crossing frame in the power engineering.

[0034] S4: Set boundary conditions for the bottom end nodes of the steel pipe crossing frame structure in finite element analysis. For the steel pipe crossing frame structure, it is usually necessary to set fixed constraints for the bottom end nodes to simulate the support conditions of the actual structure. Boundary condition setting: fixed constraints are applied to all the stand poles and the bottom nodes of the stay wire at the bottom end of the steel pipe crossing frame structure, and the displacement of these nodes is limited to 0. In this way, it can be ensured that the structure will not move or rotate as a whole during analysis, so as to more accurately reflect the actual stress condition of the structure.

[0035] S5: Select all the nodes of the steel pipe crossing frame structure under stress, and load the equivalent external force obtained to each node. Before applying the load, all the nodes of the steel pipe crossing frame structure under stress need to be determined, and the calculated equivalent external force is loaded to these nodes.

[0036] Node selection: According to the geometric shape and force condition of the structure, all nodes on the windward face of the steel pipe span structure and all nodes subjected to vertical load are selected.

[0037] Load application: Apply the calculated equivalent external force to the selected nodes. When applying the load, ensure that the direction and size of the load are consistent with the actual situation.

[0038] S6: Calculate and export the mechanical performance data of the steel pipe span structure. After completing the above steps, perform finite element analysis to calculate the mechanical performance data of the steel pipe span structure: Solution process: Use the solver of the finite element analysis software to solve the model. During the solution process, the software will calculate the stress distribution, displacement distribution and other mechanical performance data of the structure according to the applied load and boundary conditions.

[0039] The finite element analysis software analysis process is as follows: S6.1, use / SOLU command to enter the solution mode; S6.2, use ACEL command to realize the application of gravity load on the model; S6.3, use SOLVE command to start solving, and solve the mechanical property data including stress distribution data and displacement distribution data; S6.4, use / POST1 to enter the post-processing stage; S6.5, use PLNSOL command to display node displacement data in the form of cloud chart; S6.6, use ESHAPE command to display solid elements; S6.7, use PLESOL command to display element stress data in the form of cloud chart. Result export: Export the mechanical performance data obtained by solving, so as to carry out subsequent analysis and evaluation. The exported data usually includes stress cloud chart, displacement cloud chart, etc. These graphics can directly show the mechanical behavior of the structure.

[0040] Step S7, verifying model accuracy: compare the calculation results with experimental data, adjust the semi-rigid node spring stiffness parameters to ensure that the model accuracy error is less than 5%. After completing the construction of the steel pipe crossing frame mechanical analysis model, load application, boundary condition setting and mechanical property data calculation, model verification and parameter adjustment are performed. Specifically, the mechanical property data (such as stress distribution, displacement distribution, etc.) obtained by finite element analysis are compared with actual experimental data. If the error between the calculation results and the experimental data exceeds 5%, the spring stiffness parameters of the semi-rigid node need to be adjusted. By increasing or decreasing the spring stiffness, the calculation results of the model are closer to the experimental data, and the adjustment process is repeated until the model accuracy error is less than 5%. This verification step can ensure the accuracy of the finite element model and provide reliable basis for engineering design and construction.

[0041] Through the above steps S1 to S7, the present application provides a steel pipe crossing frame mechanical analysis method considering semi-rigid nodes. This method can more accurately simulate the actual mechanical behavior of the steel pipe crossing frame, improve the accuracy and efficiency of structural analysis, and provide scientific basis for power transmission line construction. After the analysis is completed, the construction form of the model can be further changed, and the mechanical properties of steel pipe crossing frames with different construction forms can be numerically simulated, so as to analyze the influence of different construction forms on the mechanical properties of steel pipe crossing frames.

[0042] For example: the height of the steel pipe crossing frame is 12.4m, the length is 14m, and the width is 6m. The vertical rod spacing is 2m, the cross rod step is 2m, and the row spacing is 3m. The wind speed is 6 grade wind, i.e. 13.8m / s. According to the above steps, the stress nephogram and displacement nephogram can be automatically generated by the post-processing module of the finite element software after the calculation is completed, which is simple, convenient and efficient. Figure 4 , Figure 5 The stress nephograms of semi-rigid connection and rigid connection crossing frames are shown in Table 1. The calculation results of the steel pipe crossing frame considering semi-rigid nodes and the steel pipe crossing frame with rigid connection (without step S2) are compared, as shown in Table 1. In the table: SMX represents the maximum equivalent stress, and DMX represents the maximum displacement.

[0043] Table 1 Comparison of steel pipe crossing frame results

[0044] From Table 1, if the influence of the semi-rigid right-angle fastener on the equivalent stress and displacement of the steel pipe span frame is not considered, and all the connecting nodes of the right-angle fastener are regarded as rigid connections, the calculation result is about 20% less than the result considering the semi-rigid connection (as shown in Table 1). This is because the semi-rigid connection is simplified for analysis, on the one hand, the lateral displacement of the span frame is underestimated, thereby weakening the influence of the P-Δ effect (P-Δ effect refers to the additional bending moment caused by the lateral displacement of the structure); on the other hand, the stiffness of the connection between the vertical rod and the horizontal rod is overestimated, and the theoretical stress and displacement of the component are small and unsafe. Therefore, the stability analysis of the steel pipe span frame must consider the influence of the semi-rigidity of the fastener connection.

[0045] After the analysis, according to the above S1-S7 steps, the corresponding program is changed, the mechanical properties of the steel pipe span frame of different structural forms are simulated, and the influence law of different structural forms on the mechanical properties of the steel pipe span frame is analyzed.

[0046] The content described in the embodiments of the specification is only a list of implementation forms of the inventive concept, and the protection scope of the present application should not be regarded as being limited to the specific forms stated in the embodiments, and the protection scope of the present application also extends to equivalent technical means that can be thought of by those skilled in the art according to the inventive concept.

Claims

1. A mechanical analysis method for steel pipe bridging frames considering semi-rigid nodes, characterized in that, Includes the following steps: S1: Construct a finite element model of the steel pipe crossing frame structure according to preset rules; S2: Replace the connection nodes of the steel pipe truss structure with semi-rigid nodes; S3: Calculate the loads on the steel pipe truss structure model and convert them into equivalent external forces; S4: Set boundary conditions for the bottom nodes of the steel pipe crossing structure; S5: Select all nodes of the steel pipe truss structure under stress, and apply the obtained equivalent external force to each node accordingly; S6: Calculate and derive the mechanical performance data of the steel pipe truss structure.

2. The method according to claim 1, characterized in that, The specific methods for constructing the finite element model in S1 include: S1.1: Obtain the spatial geometric parameters of each member based on the actual design drawings of the steel pipe truss structure, and establish a point-line model; S1.2: Simulate each member of the steel pipe truss structure; S1.3: Mesh the steel pipe truss structure model.

3. The mechanical analysis method for a steel pipe bridging frame considering semi-rigid nodes according to claim 1, characterized in that, The specific method for replacing the semi-rigid node in S2 includes: S2.1: Identify all connection nodes that need to be replaced; S2.2: Select a simulation method for semi-rigid nodes based on their mechanical properties; S2.3: Replace each connection node according to the selected simulation method; S2.4: Use loop commands to replace nodes in batches.

4. The mechanical analysis method for a steel pipe bridging frame considering semi-rigid nodes according to claim 3, characterized in that, The simulation parameters for semi-rigid nodes include: the length of the rigid zone is 5% to 15% of the length of the member; the spring stiffness is determined based on the experimental data of the node rotational stiffness; and the intermediate beam element is divided into 3 to 5 segments.

5. The mechanical analysis method for a steel pipe truss considering semi-rigid nodes according to claim 1, characterized in that, The load calculation in S3 includes vertical load calculation and wind load calculation: The formula for calculating vertical load is: In the formula: W j Vertical load under accident conditions of the steel pipe gantry; K1 is the impact coefficient, selected according to the height, ranging from 1.3 to 1.5; l y The vertical span of the crossing frame when the conductor is laid on it; m is the number of sub-conductors laid out at the same time; w is the weight per unit length of a single conductor in the construction line. The formula for calculating wind load is: For the wind load of the steel pipe cross-bridge structure; Let z be the wind vibration coefficient at height z; This is the coefficient for wind pressure height variation; The overall shape coefficient of the steel pipe crossing frame; The reference wind pressure standard value; This refers to the area of ​​the steel pipe crossing frame that withstands wind pressure.

6. The mechanical analysis method for a steel pipe bridging frame considering semi-rigid nodes according to claim 1, characterized in that, The boundary condition settings in S4 include: applying fixed constraints to all uprights and bottom nodes of the guy wires at the bottom of the steel pipe crossing frame structure, limiting the displacement of these nodes to 0.

7. The mechanical analysis method for a steel pipe bridging frame considering semi-rigid nodes according to claim 1, characterized in that, In S5, node selection is based on the geometry and stress conditions of the structure, selecting all nodes on the windward side of the steel pipe truss structure and all nodes subjected to vertical loads.

8. The mechanical analysis method for a steel pipe bridging frame considering semi-rigid nodes according to claim 1, characterized in that, When applying loads in S5, the calculated equivalent external force is applied to the selected node. When applying loads, it is necessary to ensure that the direction and magnitude of the loads match the actual situation.

9. The mechanical analysis method for a steel pipe bridging frame considering semi-rigid nodes according to claim 1, characterized in that, In S6, the solver of the finite element analysis software is used to solve the model. During the solution process, the software calculates the stress distribution and displacement distribution mechanical property data of the structure based on the applied loads and boundary conditions.

10. The mechanical analysis method for a steel pipe bridging frame considering semi-rigid nodes according to claim 1, characterized in that, It also includes step S7: comparing the calculation results with the experimental data, adjusting the stiffness parameters of the semi-rigid node springs, and ensuring that the model accuracy error is less than 5%.

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