Tower leg state determination method, system and device for power transmission tower in severe cold area, medium and product
By combining finite element simulation with heat conduction differential equations and apparent heat capacity method, the freezing damage of transmission tower legs in frigid regions can be quickly identified, solving the problem of complex and time-consuming calculations in existing technologies and realizing the need for rapid evaluation and design.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-16
- Publication Date
- 2026-03-20
AI Technical Summary
Existing technologies cannot quickly identify the frost damage to the legs of power transmission towers in frigid regions. Existing methods are complex and time-consuming to calculate, and cannot meet the needs of rapid assessment and design on engineering sites.
Finite element simulation combined with heat conduction differential equations and apparent heat capacity method is used to determine the transient temperature field and phase transition results of the water layer. Combined with the tower leg structural parameters, the compressive pressure and combined stress of ice on the tower leg are calculated to quickly determine the tower leg condition.
By employing a simplified finite element simulation method, the risk of tower leg frost damage can be quickly identified, providing rapid assessment and design support, making it suitable for on-site engineering applications.
Smart Images
Figure CN121706477A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of tower leg frost damage calculation, and in particular to a method, system, equipment, medium and product for determining the condition of tower legs of power transmission towers in extremely cold regions. Background Technology
[0002] In frigid regions (such as Songyuan in Northeast China), existing power transmission towers often experience freezing of water bodies due to low winter temperatures. When water freezes and undergoes a phase change, its volume expands by about 9%, exerting a tremendous compressive force (frost heave force) on the tower legs submerged in water. This causes severe frost damage to the tower leg steel, such as bending and plastic deformation, threatening the safety of the entire power grid.
[0003] Currently, research on power towers mainly focuses on overall stability analysis (such as icing and wind load), and there is no calculation method to analyze local frost heave damage in the tower legs to address the aforementioned background issues. Existing methods primarily analyze the overall stability of the power tower, typically using finite element analysis to construct the entire tower structure. This calculation is complex, time-consuming, and cannot quickly identify frost damage in the tower legs, making it inconvenient for rapid on-site assessment and design. Summary of the Invention
[0004] The purpose of this application is to provide a method, system, equipment, medium and product for determining the condition of tower legs of power transmission towers in extremely cold regions, so as to solve the problems of complex calculation, long time consumption and inability to quickly identify the freezing damage of tower legs.
[0005] To achieve the above objectives, this application provides the following solution: Firstly, this application provides a method for determining the leg condition of power transmission towers in frigid regions, including: Based on the finite element method, the transient temperature field of the water layer in the legs of the power transmission tower is determined according to the differential equation of heat conduction in the water layer and the boundary conditions; the transient temperature field of the water layer is used to characterize the distribution of water temperature. Based on the finite element method, the latent heat of phase change at the water-ice phase change interface is processed using the apparent heat capacity method to determine the phase change result; the phase change result is the ice thickness. The yield strength of the tower leg steel is determined based on the tower leg structural parameters; the tower leg structural parameters include the total weight of the tower body, the cross-sectional area of the steel, the section modulus of the main material, and the quantity of the main material and diagonal material of the tower leg. Based on the transient temperature field of the water layer and the ice thickness, the compressive pressure of the ice on the tower legs is determined. The combined stress of the tower legs is determined based on the tower leg structural parameters, the icing thickness, and the extrusion pressure. The tower leg condition is determined based on the combined stress of the tower legs and the yield strength of the tower leg steel; the tower leg condition includes a condition with risk of frost damage and a safe condition.
[0006] Secondly, this application provides a system for determining the leg status of power transmission towers in frigid regions, comprising: The transient temperature field determination module for water layer is used to determine the transient temperature field of the water layer at the legs of the power transmission tower based on the finite element simulation method, according to the differential equation of heat conduction in the water layer and the boundary conditions; the transient temperature field of the water layer is used to characterize the distribution of water temperature; The phase change result determination module is used to determine the phase change result by processing the latent heat of phase change at the water-ice phase change interface based on the finite element simulation method and the apparent heat capacity method; the phase change result is the ice thickness. The tower leg steel yield strength determination module is used to determine the yield strength of the tower leg steel based on the tower leg structural parameters; the tower leg structural parameters include the total weight of the tower body, the cross-sectional area of the steel, the section modulus of the main material, and the quantity of the main material and diagonal material of the tower leg; The extrusion strength determination module is used to determine the extrusion pressure of ice on the tower legs based on the transient temperature field of the water layer and the ice thickness. The tower leg combined stress determination module is used to determine the tower leg combined stress based on the tower leg structural parameters, the icing thickness, and the extrusion pressure. The tower leg condition determination module is used to determine the tower leg condition based on the combined stress of the tower leg and the yield strength of the tower leg steel; the tower leg condition includes a condition with risk of frost damage and a safe condition.
[0007] Thirdly, this application provides a computer device, including: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the above-described method for determining the leg status of power transmission towers in frigid regions.
[0008] Fourthly, this application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the above-described method for determining the leg status of power transmission towers in frigid regions.
[0009] Fifthly, this application provides a computer program product, including a computer program that, when executed by a processor, implements the above-described method for determining the leg status of power transmission towers in frigid regions.
[0010] According to the specific embodiments provided in this application, this application has the following technical effects: This application does not require the use of finite element simulation to build the entire tower structure. It mainly uses theoretical calculations, combined with a relatively simple finite element simulation method, to determine the transient temperature field of the water layer and the phase transformation results. This allows for a preliminary assessment of whether the tower legs have undergone plastic deformation. By combining the tower leg structural parameters, the yield strength of the tower leg steel is determined. Based on the transient temperature field of the water layer and the ice thickness, the compressive pressure of the ice on the tower legs is determined, resulting in the combined stress of the tower legs. Finally, the state of the tower legs is determined based on the yield strength of the tower leg steel. Compared with existing methods that use finite element simulation to build the entire tower structure, this application can quickly determine the state of the tower legs and identify the frost damage, making it easier for rapid on-site assessment and design. Attached Figure Description
[0011] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0012] Figure 1 A flowchart illustrating a method for determining the leg status of a power transmission tower in extremely cold regions, provided as an embodiment of this application; Figure 2 This is a schematic diagram of a COMSOL geometric model provided in an embodiment of this application; Figure 3 This is a partial schematic diagram of a COMSOL geometric model provided in an embodiment of this application; Figure 4 This is a schematic diagram of the transient temperature field of a water layer provided in an embodiment of this application; Figure 5 This is a schematic diagram of the phase transition result provided in an embodiment of this application; Figure 6 Stress distribution diagram of the left tower leg provided in an embodiment of this application; Figure 7 The stress distribution diagram of the right tower leg is provided for an embodiment of this application. Detailed Implementation
[0013] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.
[0014] To make the objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.
[0015] like Figure 1 As shown in the figure, this application provides a method for determining the leg status of power transmission towers in extremely cold regions, including: S1: Based on the finite element simulation method, the transient temperature field of the water layer in the tower leg of the power transmission tower is determined according to the differential equation of heat conduction in the water layer and the boundary conditions; the transient temperature field of the water layer is used to characterize the distribution of water temperature.
[0016] S2: Based on the finite element simulation method, the latent heat of phase change at the water-ice phase change interface is processed using the apparent heat capacity method to determine the phase change result; the phase change result is the ice thickness.
[0017] S3: Determine the yield strength of the tower leg steel based on the tower leg structural parameters; the tower leg structural parameters include the total weight of the tower body, the cross-sectional area of the steel, the section modulus of the main material, and the quantity of the main material and diagonal material of the tower leg.
[0018] S4: Based on the transient temperature field of the water layer and the ice thickness, determine the compressive pressure of the ice on the tower legs.
[0019] S5: Determine the combined stress of the tower legs based on the tower leg structural parameters, the icing thickness, and the extrusion pressure.
[0020] S6: Determine the tower leg condition based on the combined stress of the tower legs and the yield strength of the tower leg steel; the tower leg condition includes a condition with risk of frost damage and a safe condition.
[0021] In an exemplary embodiment, S1 specifically includes: The differential equation for heat conduction in the water layer is as follows: Where T is temperature, t is time, c is the specific heat of the material, ρ is the density of the material, and λ is the thermal conductivity. The coordinates of the water layer region are given. The heat conduction equation establishes the relationship between the temperature of an object and time and space, but there are infinitely many solutions that satisfy the heat conduction equation. In order to determine the required temperature field, the initial conditions and boundary conditions also need to be known.
[0022] At the initial instant, the temperature field is a coordinate system. A known function, when At that time, the initial conditions can be obtained: The temperature field of the water body is represented by the function T(x,y,z,t), where (x,y,z) are spatial coordinates and t is time. The initial temperature field of the water body is the temperature field at t=0, i.e., T(x,y,z,0). This represents the initial temperature field of the water body.
[0023] Based on the actual situation, the temperature boundary condition of the upper surface of the water layer adopts the third type of boundary condition, that is, the heat flow through the water layer surface and the water layer surface temperature and air temperature. The difference is directly proportional, that is: in, n The direction of the surface outward normal. β is the convective heat transfer coefficient.
[0024] Considering that the temperature of the lower surface of the water layer does not change much, it is approximately a constant temperature. The value is selected based on the actual situation, that is: In summary, based on the differential equation of heat conduction and the boundary conditions, the transient temperature field of the water layer should satisfy the following equation: in, For the specific heat of the material, For the density of the material, Thermal conductivity, Temperature.
[0025] In an exemplary embodiment, S2 specifically includes: Using the apparent heat capacity method to treat the latent heat of phase change, the heat capacity of the material can be expressed as: in, It is a phase transition function. Specific heat capacity of the material in a liquid state It is the specific heat capacity of the material when it is in a solid state. For a pure solid, For pure liquids, .
[0026] Adding a latent heat term to the above equation yields the heat capacity expression for the apparent heat capacity method: in, It is latent heat.
[0027] The transient temperature field of the water layer obtained from S1 is used to determine the phase state of the water layer. The apparent heat capacity method is then used to handle the abrupt change at the water-ice interface, thus obtaining the phase transition result, i.e., the ice thickness. The phase transition result can be calculated using finite element simulation software. This application employs the apparent heat capacity method to handle the abrupt change at the water-ice phase transition interface during finite element simulation. C p The rewriting reflects the principle of the apparent heat capacity method.
[0028] In an exemplary embodiment, S3 specifically includes: Obtain the structural parameters of the tower legs, including the total weight of the tower body, the quantity, cross-sectional area, and section modulus of the main and diagonal materials of the tower legs, and determine the yield strength and elastic modulus of the tower leg steel. Then, in combination with the ice thickness, take the ice compressive strength of 1-5 MPa as the compressive strength of the ice layer based on the ambient temperature as the compressive strength of the ice on the tower legs, such as conservatively taking 5 MPa.
[0029] In an exemplary embodiment, S5 specifically includes: S51: Determine the phase change expansion force on a single tower leg based on the quantity of the main and diagonal members of the tower leg, the ice thickness, and the extrusion pressure.
[0030] S52: Determine the combined load on the tower legs based on the total weight of the tower body and the phase change expansion force.
[0031] S53: Determine the combined stress of the tower leg based on the combined load, the cross-sectional area of the steel, and the section modulus of the main material.
[0032] In an exemplary embodiment, S51 specifically includes: S511: The width of the stress concentration area at the inner corner of the angle steel is taken as the contact area width; the contact area width includes the contact area width of the main material and the contact area width of the diagonal material.
[0033] S512: Determine the effective contact area of the main material based on the number of main materials of the tower leg, the thickness of the ice layer, and the width of the contact area of the main material.
[0034] S513: Determine the effective contact area of the inclined members based on the number of inclined members in the tower leg, the thickness of the ice layer, and the width of the contact area of the inclined members.
[0035] S514: Determine the total effective contact area of a single tower leg based on the effective contact area of the main material and the effective contact area of the inclined material.
[0036] S515: Determine the phase change expansion force on a single tower leg based on the total effective contact area and the extrusion pressure.
[0037] In practical applications, the effective contact area between the tower leg angle steel and the ice layer is determined. This area can be calculated by taking the width of the stress concentration area within the angle steel as the contact area width, and then multiplying it by the ice-soaking length (i.e., ice thickness) and the number of main or diagonal members to obtain the effective contact area of the main or diagonal members, respectively. in, S 1 is the effective contact area of the main material. S 2 represents the effective contact area of the diagonal members. m、n The quantities of main materials and diagonal materials are respectively. L This is the length of the ice immersion. d 1. d2 is the width of the contact area between the main material and the diagonal material. It can be taken as 0.2 times the side length of the angle steel as the width of the contact area, which roughly covers the local high stress area extending outward from the inner corner of the angle steel.
[0038] Then, the effective contact areas calculated from the main material and the diagonal material are added together to obtain the total effective contact area of a single tower leg. Finally, the total effective contact area is multiplied by the compressive pressure exerted by the ice on the tower leg to obtain the phase change expansion force on a single tower leg. ,Right now: in, For compressive strength, For effective contact area.
[0039] In an exemplary embodiment, S52 specifically includes: S521: Based on the total weight of the tower body, calculate the self-weight load distributed to each individual tower leg; S522: Determine the combined load on the tower leg based on the phase change expansion force and the self-weight load of a single tower leg.
[0040] In practical applications, the self-weight of the tower is first calculated and distributed to each individual tower leg. Then, based on the phase change expansion force obtained in step four, the phase change expansion force and the self-weight load on each individual tower leg are added together to obtain the combined load on the tower leg, i.e.: in, This refers to the self-weight load on a single tower leg.
[0041] In an exemplary embodiment, S53 specifically includes: S531: Calculate the axial stress caused by the combined load on the tower leg based on the combined load and the cross-sectional area of the steel.
[0042] S532: Calculate the bending moment caused by the phase transformation expansion force on the tower leg.
[0043] S533: Based on the bending moment, the phase change expansion force is simplified into a load uniformly distributed along the ice thickness, and the main tower leg is simplified into a cantilever beam model to calculate the maximum bending moment.
[0044] S534: Determine the maximum bending stress based on the maximum bending moment and the section modulus of the main material.
[0045] S535: Determine the combined stress of the tower legs based on the axial stress and the maximum bending stress.
[0046] In practical applications, the axial stress caused by the combined load on the tower leg is calculated using the combined load method. The calculation result can be obtained by dividing the combined load by the cross-sectional area of the steel, that is: in, This represents the cross-sectional area of the steel.
[0047] Then, the bending moment caused by the phase change expansion force on the tower leg is calculated. The phase change expansion force can be simplified as a load uniformly distributed along the ice thickness. The main material of the tower leg is simplified as a cantilever beam model. The maximum bending moment M is calculated, and then the maximum bending stress is obtained. ,Right now: in, It is the section modulus of the main material.
[0048] Finally, the axial stress With maximum bending stress By superimposing stresses and considering the stress concentration effect at the interior angle of the angle steel, the combined stress of the tower legs is obtained. ,Right now: in, is the stress concentration factor.
[0049] In one exemplary embodiment, S6 specifically includes: S61: When the combined stress of the tower legs is greater than the yield strength of the tower leg steel, it is determined that the tower legs will undergo plastic deformation, and the tower legs are determined to be in a state of risk of frost damage.
[0050] S62: When the combined stress of the tower leg is less than or equal to the yield strength of the tower leg steel, it is determined that the tower leg is within the elastic range and the tower leg state is determined to be a safe state.
[0051] Compared to complex finite element simulations that build a simulation model of the entire tower, this application is based on clear theoretical formulas, has well-defined input parameters, and is fast in calculation. It is very suitable for engineering technicians to quickly and quantitatively assess the risk of tower leg frost damage on-site or during the design phase. Furthermore, this application directly focuses on the core physical mechanism of water-ice phase change expansion force. Through theoretical calculations, it clarifies how frost heave force is transformed into the key stress that leads to tower leg yielding. The principle is clear and the physical meaning is explicit.
[0052] By comparing the calculation results, it can be determined whether the tower legs will be damaged, providing accurate data support and theoretical basis for the anti-freezing design and operation and maintenance strategies of the tower; and the conclusions drawn in this application can be effectively verified by the following finite element simulation, ensuring the scientificity and reliability of the calculation method.
[0053] Simulation process and results: The 220kV transmission tower in Songyuan City is 18 meters high, with a base span of 0.557 meters and a weight of approximately 7 tons. The main material of the tower leg angle steel is L125×10, with a cross-sectional area of 0.0024m². 2 The diagonal brace has dimensions of L70×5 and a cross-sectional area of 0.000675m². 2 Based on the tower leg structure of the 2K1-J1 corner tower in Songyuan area, a three-dimensional geometric model was constructed. The model consists of the tower leg structure and a water layer. The tower leg model is 2.5m high, and the water layer has a radius of 5m and a height of 1m. The main and diagonal steel materials are Q345, and the auxiliary materials are Q235. An elastoplastic constitutive model of the steel was selected, and parameters such as the steel's yield strength, elastic modulus, and Poisson's ratio were given. Some material settings and the COMSOL geometric model are shown below. Figures 2-3 As shown.
[0054] The model's initial temperature was 10 degrees Celsius. The ambient temperature decreased from 0 degrees Celsius to -20 degrees Celsius, and this cycle continued for 60 days, totaling 1440 hours. The water layer was surrounded by an adiabatic boundary, with a fixed boundary temperature of 4 degrees Celsius at the bottom. The bottom of the tower legs and the area around the water layer were also subject to fixed constraints.
[0055] The steel members of the tower legs are connected using grade 4.8 bolts, and the steel members are connected to the boot plates using grade 6.8 bolts. Two physical fields were used: solid mechanics and solid-fluid heat transfer. In the solid-fluid heat transfer physical field, phase change materials were added to simulate the phase change process. In the solid mechanics physical field, pre-strain was set to simulate the change in water ice volume during the phase change process, while the self-weight of the tower was also added.
[0056] Simulation results are as follows Figures 4-5 As shown in the temperature field distribution diagram and phase change results, it can be seen that after 60 days of external temperature changes, 30% of the ice-water phase change layer underwent a phase change, and the ice thickness was about 0.3m, which is consistent with the field conditions.
[0057] like Figures 6-7 As shown in the simulation results of the stress distribution of the tower leg, the maximum stress of the steel reached about 800 MPa, and the tower leg underwent some bending deformation and frost damage, which is consistent with the calculation results obtained in this application.
[0058] This application provides a system for determining the leg condition of power transmission towers in frigid regions, including: The transient temperature field determination module for water layer is used to determine the transient temperature field of the water layer on the legs of the power transmission tower based on the finite element simulation method, according to the differential equation of heat conduction of the water layer and the boundary conditions; the transient temperature field of the water layer is used to characterize the distribution of water temperature.
[0059] The phase change result determination module is used to determine the phase change result by processing the latent heat of phase change at the water-ice phase change interface based on the finite element simulation method and the apparent heat capacity method; the phase change result is the ice thickness.
[0060] The tower leg steel yield strength determination module is used to determine the yield strength of the tower leg steel based on the tower leg structural parameters; the tower leg structural parameters include the total weight of the tower body, the cross-sectional area of the steel, the section modulus of the main material, and the quantity of the main material and diagonal material of the tower leg.
[0061] The extrusion strength determination module is used to determine the extrusion pressure of ice on the tower legs based on the transient temperature field of the water layer and the ice thickness.
[0062] The tower leg combined stress determination module is used to determine the tower leg combined stress based on the tower leg structural parameters, the icing thickness, and the extrusion pressure.
[0063] The tower leg condition determination module is used to determine the tower leg condition based on the combined stress of the tower leg and the yield strength of the tower leg steel; the tower leg condition includes a condition with risk of frost damage and a safe condition.
[0064] In an exemplary embodiment, a computer device is provided, including a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the steps in the above-described method embodiments. The computer device can be a server or a terminal. The computer device includes a processor, a memory, an input / output interface (I / O), and a communication interface. The processor, memory, and I / O interface are connected via a system bus, and the communication interface is connected to the system bus via the I / O interface. The processor of the computer device provides computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and internal memory. The non-volatile storage medium stores an operating system, a computer program, and a database. The internal memory provides an environment for the operation of the operating system and computer program in the non-volatile storage medium. The database of the computer device stores data to be processed. The I / O interface of the computer device is used for exchanging information between the processor and external devices. The communication interface of the computer device is used for communicating with an external terminal via a network connection. When the computer program is executed by the processor, it implements the above-described methods.
[0065] In one exemplary embodiment, a computer device is provided, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps in the above-described method embodiments.
[0066] In one exemplary embodiment, a computer-readable storage medium is provided storing a computer program that, when executed by a processor, implements the steps in the above-described method embodiments.
[0067] In one exemplary embodiment, a computer program product is provided, including a computer program that, when executed by a processor, implements the steps in the above-described method embodiments.
[0068] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, data stored, data displayed, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of the relevant data must comply with relevant regulations.
[0069] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by hardware related to computer program instructions. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments described above. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM).
[0070] The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, etc., and are not limited to these.
[0071] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0072] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.
Claims
1. A method for determining the leg condition of a power transmission tower in frigid regions, characterized in that, include: Based on the finite element simulation method, the transient temperature field of the water layer in the legs of the power transmission tower is determined according to the differential equation of heat conduction in the water layer and the boundary conditions. The transient temperature field of the water layer is used to characterize the distribution of water temperature; Based on the finite element method, the latent heat of phase change at the water-ice phase change interface is processed using the apparent heat capacity method to determine the phase change result; the phase change result is the ice thickness. The yield strength of the tower leg steel is determined based on the tower leg structural parameters; the tower leg structural parameters include the total weight of the tower body, the cross-sectional area of the steel, the section modulus of the main material, and the quantity of the main material and diagonal material of the tower leg. Based on the transient temperature field of the water layer and the ice thickness, the compressive pressure of the ice on the tower legs is determined. The combined stress of the tower legs is determined based on the tower leg structural parameters, the icing thickness, and the extrusion pressure. The tower leg condition is determined based on the combined stress of the tower legs and the yield strength of the tower leg steel; the tower leg condition includes a condition with risk of frost damage and a safe condition.
2. The method for determining the leg condition of power transmission towers in frigid regions according to claim 1, characterized in that, The combined stress of the tower legs is determined based on the tower leg structural parameters, the icing thickness, and the compressive stress, specifically including: The phase change expansion force on a single tower leg is determined based on the quantity of main and diagonal members of the tower leg, the ice thickness, and the extrusion pressure. The combined load on the tower legs is determined based on the total weight of the tower body and the phase change expansion force. The combined stress of the tower leg is determined based on the combined load, the cross-sectional area of the steel, and the section modulus of the main material.
3. The method for determining the leg condition of transmission towers in frigid regions according to claim 2, characterized in that, The phase transformation expansion force on a single tower leg is determined based on the quantity of main and diagonal members of the tower leg, the ice thickness, and the extrusion pressure, specifically including: The width of the stress concentration area at the inner corner of the angle steel is taken as the contact area width; the contact area width includes the contact area width of the main material and the contact area width of the diagonal material. The effective contact area of the main material is determined based on the number of main materials for the tower legs, the thickness of the ice layer, and the width of the contact area of the main material. The effective contact area of the inclined members is determined based on the number of inclined members in the tower leg, the thickness of the ice formation, and the width of the contact area of the inclined members. The total effective contact area of a single tower leg is determined based on the effective contact area of the main material and the effective contact area of the diagonal material. The phase change expansion force on a single tower leg is determined based on the total effective contact area and the compressive pressure.
4. The method for determining the leg condition of power transmission towers in frigid regions according to claim 2, characterized in that, The combined load on the tower legs is determined based on the total weight of the tower body and the phase change expansion force, specifically including: Based on the total weight of the tower, calculate the self-weight load distributed to each individual tower leg; The combined load on the tower leg is determined based on the phase change expansion force and the self-weight load of a single tower leg.
5. The method for determining the leg condition of transmission towers in frigid regions according to claim 2, characterized in that, The combined stress of the tower leg is determined based on the combined load, the cross-sectional area of the steel, and the section modulus of the main material, specifically including: Calculate the axial stress caused by the combined load on the tower leg based on the combined load and the cross-sectional area of the steel. Calculate the bending moment caused by the phase transformation expansion force on the tower legs; Based on the bending moment, the phase change expansion force is simplified into a load uniformly distributed along the ice thickness, and the main tower leg is simplified into a cantilever beam model to calculate the maximum bending moment. The maximum bending stress is determined based on the maximum bending moment and the section modulus of the main material. The combined stress of the tower legs is determined based on the axial stress and the maximum bending stress.
6. The method for determining the leg condition of transmission towers in frigid regions according to claim 1, characterized in that, The tower leg condition is determined based on the combined stress of the tower legs and the yield strength of the tower leg steel, specifically including: When the combined stress of the tower legs exceeds the yield strength of the tower leg steel, it is determined that the tower legs will undergo plastic deformation, and the tower legs are determined to be in a state of risk of frost damage. When the combined stress of the tower legs is less than or equal to the yield strength of the tower leg steel, the tower leg condition is determined to be a safe condition.
7. A system for determining the leg status of power transmission towers in frigid regions, characterized in that, The tower leg status determination system for power transmission towers in frigid regions executes the tower leg status determination method for power transmission towers in frigid regions according to any one of claims 1-6, wherein the tower leg status determination system for power transmission towers in frigid regions includes: The transient temperature field determination module for water layer is used to determine the transient temperature field of the water layer at the legs of the power transmission tower based on the finite element simulation method, according to the differential equation of heat conduction in the water layer and the boundary conditions; the transient temperature field of the water layer is used to characterize the distribution of water temperature; The phase change result determination module is used to determine the phase change result by processing the latent heat of phase change at the water-ice phase change interface based on the finite element simulation method and the apparent heat capacity method; the phase change result is the ice thickness. The tower leg steel yield strength determination module is used to determine the yield strength of the tower leg steel based on the tower leg structural parameters; the tower leg structural parameters include the total weight of the tower body, the cross-sectional area of the steel, the section modulus of the main material, and the quantity of the main material and diagonal material of the tower leg; The extrusion strength determination module is used to determine the extrusion pressure of ice on the tower legs based on the transient temperature field of the water layer and the ice thickness. The tower leg combined stress determination module is used to determine the tower leg combined stress based on the tower leg structural parameters, the icing thickness, and the extrusion pressure. The tower leg condition determination module is used to determine the tower leg condition based on the combined stress of the tower leg and the yield strength of the tower leg steel; the tower leg condition includes a condition with risk of frost damage and a safe condition.
8. A computer device, comprising: A memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that the processor executes the computer program to implement the method for determining the leg status of a power transmission tower in a frigid region as described in any one of claims 1-6.
9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When executed by a processor, the computer program implements the method for determining the leg status of power transmission towers in frigid regions as described in any one of claims 1-6.
10. A computer program product, comprising a computer program, characterized in that, When executed by a processor, the computer program implements the method for determining the leg status of power transmission towers in frigid regions as described in any one of claims 1-6.