A method and device for field measurement and evaluation of stress state of a tower

Abstract

The present application relates to the technical field of power transmission line disaster prevention and mitigation, and specifically provides a method and device for field measurement and evaluation of the stress state of a tower, comprising: determining dangerous members on the tower based on the stress ratios of the members of the tower; determining the average stress of the cross section of each preset measurement position at the maximum stress position of the dangerous member based on the strain values of the cross section of each preset measurement position at the maximum stress position of the dangerous member; and evaluating the safety of the stress state of the tower based on the average stress of the cross section of each preset measurement position at the maximum stress position of the dangerous member. The technical solution provided by the present application can measure the stress state of the tower in a more direct and accurate manner, thereby providing basic data support for tower safety early warning and avoiding the use of indirect load monitoring methods that introduce excessive errors and cause distortion in tower safety early warning.

Description

Technical Field

[0001] This invention relates to the field of disaster prevention and mitigation technology for power transmission lines, specifically to a method and apparatus for on-site measurement and evaluation of the stress state of transmission towers. Background Technology

[0002] Transmission towers are spatial truss structures with numerous members subjected to varying spatial forces, making their mechanical state extremely difficult to grasp. Conventional methods involve monitoring external environmental parameters such as wind speed, wind direction, and icing, and then using finite element method (FEM) stress simulation analysis to describe the tower's stress state. However, the actual stress state of the tower is inevitably affected by the discrepancies between the simulation analysis and the actual structure. The stress state of the tower members obtained solely from simulation analysis is often inaccurate and may differ significantly from the actual stress state. Therefore, on-site measurement of the tower's stress state to monitor the stress state of its main load-bearing components is more reliable than indirect calculations. Against this backdrop, it is necessary to propose an on-site measurement and evaluation method for the stress state of transmission towers. Summary of the Invention

[0003] To overcome the above-mentioned shortcomings, this invention proposes a method and apparatus for on-site measurement and evaluation of the stress state of iron towers.

[0004] Firstly, a field measurement and evaluation method for the stress state of a steel tower is provided, the method comprising:

[0005] The critical members on the tower are determined based on the stress ratio of each member.

[0006] The average stress of the cross section at each preset measurement position at the maximum stress position of the dangerous member is determined based on the strain value of the cross section at each preset measurement position at the maximum stress position of the dangerous member.

[0007] The safety of the tower's stress state is assessed by measuring the average stress of the cross sections at each preset measurement location at the location of maximum stress in the dangerous member.

[0008] Preferably, the formula for calculating the stress ratio of each member of the tower is as follows:

[0009]

[0010] In the above formula, λ is the stress ratio of the member, σ is the stress of the member, and σ p This represents the ultimate stress value of the material corresponding to the member.

[0011] Preferably, the determination of dangerous members on the tower based on the stress ratio of each member of the tower includes: when the stress ratio of a member of the tower exceeds a preset range, the member is considered a dangerous member.

[0012] Preferably, the strain values ​​of each section at the maximum stress location of the dangerous member are obtained by strain gauges arranged at each section at the maximum stress location of the dangerous member.

[0013] Furthermore, the formula for calculating the average stress of the cross-section at each preset measurement position at the maximum stress location of the dangerous member is as follows:

[0014]

[0015] In the above formula, The average stress of the cross section at each preset measurement position at the maximum stress location of the dangerous member, l i ε is the length of the cross section at the i-th preset measurement position at the location of maximum stress in the critical member. i E is the strain value measured by the strain gauge at the i-th preset measurement position of the maximum stress location of the dangerous member, E is the elastic modulus of the cross-sectional material at each preset measurement position of the maximum stress location of the dangerous member, N is the total number of preset measurement positions at the maximum stress location of the dangerous member, and C is the perimeter of the test cross-section.

[0016] Preferably, the assessment of the tower's stress state safety based on the average stress of cross sections at each preset measurement location at the maximum stress position of the dangerous member includes:

[0017] The average stress of the cross sections at each preset measurement position at the maximum stress location of the dangerous member. satisfy At that time, the stress state of the tower is safe;

[0018] The average stress of the cross sections at each preset measurement position at the maximum stress location of the dangerous member. satisfy At that time, the stress state of the tower is unsafe;

[0019] Where, σ p η is the ultimate stress value of the material corresponding to the member, P is the alarm threshold for the dangerous state of the member, and η is the strength improvement coefficient of the member material during the strengthening stage.

[0020] Secondly, a field measurement and evaluation device for the stress state of a steel tower is provided, the field measurement and evaluation device for the stress state of the steel tower comprising:

[0021] The first determination module is used to determine the dangerous members on the tower based on the stress ratio of each member of the tower.

[0022] The second determining module is used to determine the average stress of the cross section at each preset measurement position at the maximum stress position of the dangerous member based on the strain value of the cross section at each preset measurement position at the maximum stress position of the dangerous member.

[0023] The evaluation module is used to assess the safety of the tower's stress state based on the average stress of the cross sections at each preset measurement location at the maximum stress position of the dangerous member.

[0024] Thirdly, a storage medium is provided, the storage medium including a stored program, wherein, when the program is running, the device where the storage medium is located is controlled to execute the on-site measurement and evaluation method for the stress state of the iron tower.

[0025] Fourthly, a processor is provided for running a program, wherein the program executes the on-site measurement and evaluation method for the stress state of the iron tower.

[0026] The above-described technical solutions of the present invention have at least one or more of the following beneficial effects:

[0027] This invention provides a method and apparatus for on-site measurement and evaluation of the stress state of a steel tower, comprising: identifying the critical members of the tower based on the stress ratio of each member; determining the average stress of the cross-section at each preset measurement position of the critical member based on the strain value of the cross-section at the maximum stress position of the critical member; and evaluating the safety of the tower's stress state based on the average stress of the cross-section at each preset measurement position of the critical member. The technical solution provided by this invention can measure the stress state of a steel tower in a more direct and accurate manner, thereby providing basic data support for tower safety early warning and avoiding the introduction of excessive errors that lead to distorted tower safety early warnings when using indirect load monitoring methods. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the main steps of the on-site measurement and evaluation method for the stress state of iron towers according to an embodiment of the present invention;

[0029] Figure 2 This describes the distribution of stress-prone members on the tower according to an embodiment of the present invention.

[0030] Figure 3 This refers to the installation position of the strain gauge on a single rod according to an embodiment of the present invention;

[0031] Figure 4 This is a main structural block diagram of the field measurement and evaluation device for the stress state of iron towers according to an embodiment of the present invention. Detailed Implementation

[0032] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0033] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. 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.

[0034] See appendix Figure 1 , Figure 1 This is a schematic flowchart illustrating the main steps of an embodiment of the present invention for on-site measurement and evaluation of the stress state of a steel tower. Figure 1 As shown, the on-site measurement and evaluation method for the stress state of the iron tower in this embodiment of the invention mainly includes the following steps:

[0035] Step S101: Determine the critical members on the tower based on the stress ratio of each member;

[0036] Step S102: Determine the average stress of the cross section at each preset measurement position at the maximum stress position of the dangerous member based on the strain value of the cross section at each preset measurement position at the maximum stress position of the dangerous member.

[0037] Step S103: Assess the safety of the tower's stress state based on the average stress of the cross sections at each preset measurement location at the maximum stress position of the dangerous member.

[0038] In this embodiment, the formula for calculating the stress ratio of each member of the tower is as follows:

[0039]

[0040] In the above formula, λ is the stress ratio of the member, σ is the stress of the member, and σ p This represents the ultimate stress value of the material corresponding to the member.

[0041] In this embodiment, the determination of dangerous members on the tower based on the stress ratio of each member of the tower includes: when the stress ratio of a member of the tower exceeds a preset range, the member is considered a dangerous member.

[0042] In this embodiment, the strain values ​​of each section at the maximum stress location of the dangerous member are obtained by strain gauges arranged at each section at the maximum stress location of the dangerous member.

[0043] In one embodiment, the formula for calculating the average stress of the cross-section at each preset measurement position at the maximum stress location of the dangerous member is as follows:

[0044]

[0045] In the above formula, The average stress of the cross section at each preset measurement position at the maximum stress location of the dangerous member, l i ε is the length of the cross section at the i-th preset measurement position at the location of maximum stress in the critical member. i E is the strain value measured by the strain gauge at the i-th preset measurement position of the maximum stress location of the dangerous member, E is the elastic modulus of the cross-sectional material at each preset measurement position of the maximum stress location of the dangerous member, N is the total number of preset measurement positions at the maximum stress location of the dangerous member, and C is the perimeter of the test cross-section.

[0046] In this embodiment, the safety assessment of the tower's stress state based on the average stress of the cross-sections at each preset measurement location at the maximum stress position of the dangerous member includes:

[0047] The average stress of the cross sections at each preset measurement position at the maximum stress location of the dangerous member. satisfy At that time, the stress state of the tower is safe;

[0048] The average stress of the cross sections at each preset measurement position at the maximum stress location of the dangerous member. satisfy At that time, the stress state of the tower is unsafe;

[0049] Where, σ p η is the ultimate stress value of the material corresponding to the member, P is the alarm threshold for the dangerous state of the member, and η is the strength improvement coefficient of the member material during the strengthening stage, which is generally between 1.0 and 1.2.

[0050] Furthermore, this invention provides an optimal implementation method, using the stress state monitoring-based safety status assessment of a certain iron tower as an example to introduce the patent application.

[0051] (1) Stress calculation of tower members

[0052] A calculation model for the iron tower is established, and the prevailing wind direction angle is given as 45 degrees. The stress of the tower members is calculated under this inflow wind direction angle.

[0053] (2) Search for dangerous pole locations

[0054] Extract the stress calculation results of the tower members. The member material is Q345 steel, and the corresponding ultimate stress σ is... p The stress is 345 MPa. Based on the stress calculation values ​​of each member, and according to the formula... The calculated stress ratios of the members are shown in Table 1. A stress ratio threshold κ = 0.9 is set. Members with stress ratios greater than this threshold require the highest priority for monitoring. This determines the locations of potentially hazardous members. Figure 2 As shown;

[0055] Table 1

[0056] Sort Member Number Stress ratio 1 50-210 1.09 2 170-372 1.09 3 530-690 0.99 4 210-390 0.98 5 10-50 0.93

[0057] (3) Strain monitoring of critical members

[0058] At the location of maximum stress in the identified critical member, the cross-sectional shape of all five members is as follows. Figure 3 As shown in the diagram, four strain gauges are attached and fixed at the midpoints of the four corner limbs of the rectangular cross-section.

[0059] (4) Stress monitoring of dangerous members

[0060] Taking the L40×3 equilateral angle steel member with the largest stress ratio as an example, the cross-sectional strain values ​​obtained from testing four strain gauges of this section are substituted into the formula. The average stress of the entire cross section is calculated, where l i The lengths of the cross-sections at the i-th preset measurement position, where the maximum stress is located in the critical member, are 37mm, 40mm, 37mm, and 40mm, respectively; ε i The strain values ​​measured by strain gauges at the i-th preset measurement position of the maximum stress location in the critical member are 162, 159, 167, and 164, respectively; E is the elastic modulus of the cross-sectional material at each preset measurement position of the maximum stress location in the critical member, which is 2.09 × 10⁻⁶ for steel. 11 Pa, N represents the total number of preset measurement locations at the maximum stress position of the critical member, and C represents the perimeter of the test section, which is 154 mm. The calculated average stress... The pressure is 34 MPa.

[0061] (5) Evaluation of stress state of members

[0062] The ultimate stress σ of Q345 bar material p With a stress level of 345 MPa, the alarm threshold P = 75 for dangerous conditions of the tower members is set. The safety of the stress state of the tower members is evaluated. The result is that 34 ≤ 345 × 75% = 258.75, indicating that the stress state of the tower is safe.

[0063] Based on the same inventive concept, this invention provides a field measurement and evaluation device for the stress state of iron towers, such as... Figure 4 As shown, the field measurement and evaluation device for the stress state of the iron tower includes:

[0064] The first determination module is used to determine the dangerous members on the tower based on the stress ratio of each member of the tower.

[0065] The second determining module is used to determine the average stress of the cross section at each preset measurement position at the maximum stress position of the dangerous member based on the strain value of the cross section at each preset measurement position at the maximum stress position of the dangerous member.

[0066] The evaluation module is used to assess the safety of the tower's stress state based on the average stress of the cross sections at each preset measurement location at the maximum stress position of the dangerous member.

[0067] Preferably, the formula for calculating the stress ratio of each member of the tower is as follows:

[0068]

[0069] In the above formula, λ is the stress ratio of the member, σ is the stress of the member, and σ p This represents the ultimate stress value of the material corresponding to the member.

[0070] Preferably, the determination of dangerous members on the tower based on the stress ratio of each member of the tower includes: when the stress ratio of a member of the tower exceeds a preset range, the member is considered a dangerous member.

[0071] Preferably, the strain values ​​of each section at the maximum stress location of the dangerous member are obtained by strain gauges arranged at each section at the maximum stress location of the dangerous member.

[0072] Furthermore, the formula for calculating the average stress of the cross-section at each preset measurement position at the maximum stress location of the dangerous member is as follows:

[0073]

[0074] In the above formula, The average stress of the cross section at each preset measurement position at the maximum stress location of the dangerous member, l i ε is the length of the cross section at the i-th preset measurement position at the location of maximum stress in the critical member. i E is the strain value measured by the strain gauge at the i-th preset measurement position of the maximum stress location of the dangerous member, E is the elastic modulus of the cross-sectional material at each preset measurement position of the maximum stress location of the dangerous member, N is the total number of preset measurement positions at the maximum stress location of the dangerous member, and C is the perimeter of the test cross-section.

[0075] Preferably, the assessment of the tower's stress state safety based on the average stress of cross sections at each preset measurement location at the maximum stress position of the dangerous member includes:

[0076] The average stress of the cross sections at each preset measurement position at the maximum stress location of the dangerous member. satisfy At that time, the stress state of the tower is safe;

[0077] The average stress of the cross sections at each preset measurement position at the maximum stress location of the dangerous member. satisfy At that time, the stress state of the tower is unsafe;

[0078] Where, σ p η is the ultimate stress value of the material corresponding to the member, P is the alarm threshold for the dangerous state of the member, and η is the strength improvement coefficient of the member material during the strengthening stage.

[0079] Furthermore, the present invention provides a storage medium comprising a stored program, wherein, when the program is executed, the device containing the storage medium is controlled to perform the on-site measurement and evaluation method for the stress state of the iron tower.

[0080] Furthermore, the present invention provides a processor for running a program, wherein the program executes the on-site measurement and evaluation method for the stress state of the iron tower.

[0081] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0082] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0083] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0084] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0085] 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 it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for evaluating a stress state of a tower in situ, characterized by, The method comprises: determining a dangerous member on the tower based on a stress ratio of each member of the tower; determining an average stress of a cross section of each preset measurement position at a maximum stress position of the dangerous member based on a strain value of the cross section of each preset measurement position at the maximum stress position of the dangerous member; evaluating the safety of the stress state of the tower based on the average stress of the cross section of each preset measurement position at the maximum stress position of the dangerous member; a calculation formula of the stress ratio of each member of the tower is as follows: In the above formula, λ is the stress ratio of the rod, σ is the stress of the rod, σ p is the limit stress value of the rod corresponding to the material; the dangerous member on the tower is determined based on the stress ratio of each member of the tower, and when the stress ratio of the member of the tower exceeds a preset range, the member is the dangerous member; the strain value of each cross section at the maximum stress position of the dangerous member is obtained through a strain gauge arranged at each cross section at the maximum stress position of the dangerous member; a calculation formula of the average stress of the cross section of each preset measurement position at the maximum stress position of the dangerous member is as follows: In the above formula, is the average stress of the cross section at each preset measurement position at the maximum stress position of the dangerous rod member, l i is the length of the cross section at the i-th preset measurement position at the maximum stress position of the dangerous rod member, ε i is the strain value of the strain gauge test at the cross section at the i-th preset measurement position at the maximum stress position of the dangerous rod member, E is the elastic modulus of the cross section material at each preset measurement position at the maximum stress position of the dangerous rod member, N is the total number of preset measurement positions at the maximum stress position of the dangerous rod member, and C is the circumference of the test cross section. the safety of the stress state of the tower is evaluated based on the average stress of the cross section of each preset measurement position at the maximum stress position of the dangerous member, and the evaluation comprises: When the average stress of the section at each preset measurement position at the maximum stress position of the danger rod member is satisfied , the stress state of the tower is safe; When the average stress of the section at each preset measurement position at the maximum stress position of the danger rod member is satisfied , the stress state of the tower is unsafe; Wherein, σ p is the limit stress value of the corresponding material of the rod, P is the dangerous state alarm threshold value of the rod, and η is the strength improvement coefficient of the material strengthening stage of the rod.

2. A device for evaluating a stress state of a tower based on a field measurement method according to claim 1, characterized by The device comprises: a first determination module configured to determine a dangerous member on the tower based on a stress ratio of each member of the tower; a second determination module configured to determine an average stress of a cross section of each preset measurement position at a maximum stress position of the dangerous member based on a strain value of the cross section of each preset measurement position at the maximum stress position of the dangerous member; an evaluation module configured to evaluate the safety of the stress state of the tower based on the average stress of the cross section of each preset measurement position at the maximum stress position of the dangerous member.

3. A storage medium, characterized by The storage medium comprises a stored program, wherein the program controls a device where the storage medium is located to execute the method of claim 1 when the program is running.

4. A processor, comprising: The processor is configured to run a program, wherein the program executes the method of claim 1 when the program is running.

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