A method and system for calculating the wind load shape coefficient of angle steel transmission tower

Abstract

The present invention provides a method and system for calculating the wind load shape coefficient of an angle steel transmission tower. Based on a pre-constructed full-scale wind tunnel test model of an angle steel transmission tower segment, the leeward wind load reduction coefficient of the angle steel tower is determined; based on a pre-established body coefficient library of angle steel components at various wind direction angles, the wind load shape coefficient of the single-piece truss on the windward side of the angle steel transmission tower segment is obtained, and the normal wind angle adjustment coefficient is used to correct the wind load shape coefficient of the single-piece truss on the windward side of the angle steel transmission tower segment; according to the corrected wind load shape coefficient of the single-piece truss on the windward side of the angle steel transmission tower segment and the leeward wind load reduction coefficient of the angle steel tower, the wind load shape coefficient of the angle steel tower is calculated. The above scheme has broad application prospects and high calculation accuracy, and provides a reference and basis for accurately calculating the wind load of the angle steel transmission tower.

Description

Technical Field

[0001] The invention belongs to the field of transmission line design load calculation methods, and specifically relates to a method and system for calculating the wind load shape coefficient of an angle steel transmission tower. Background Art

[0002] Angle steel towers for transmission lines are widely used in power transmission projects. Wind load is the controlling load in the design of angle steel transmission towers. Calculating the wind load shape coefficient of angle steel transmission tower segments is a key issue in the wind-resistant design of angle steel transmission towers.

[0003] The wind load effect of angle steel transmission tower belongs to the typical category of blunt body flow, which is often accompanied by airflow separation, reattachment and vortex shedding, and its Reynolds number effect is relatively complex. As one of the key parameters for calculating the wind load of angle steel transmission tower, the wind load shape factor is generally related to the shape of the component, the aspect ratio of the tower, the surrounding shielding effect and the filling rate of the angle steel transmission tower segment.

[0004] At present, the wind load shape coefficient of the segment is generally considered according to the overall segment or the windward side of the segment. The current design standard (DL / T5154-2012 Technical Specifications for Structural Design of Overhead Transmission Line Towers) stipulates that the wind load shape coefficient of the angle steel transmission tower segment is 1.3(1+η), where η is the leeward side reduction coefficient of the tower, and η can be obtained by looking up the filling coefficient As / A and b / a. As is the projected area of ​​the windward side component, A is the outline area of ​​the tower, a is the windward side width of the tower, and b is the distance between the windward and leeward sides of the tower.

[0005] ASCE74-2009 US transmission line tower structure design technical regulations are based on the consideration of the windward side, and the wind force coefficient (wind load shape coefficient) of the square and triangular cross-section truss structures is calculated according to the different filling rates of the windward side. EN50341-1:2001 EU transmission line design specifications first calculate the filling rate, and then calculate the shape coefficient based on the relationship diagram between the filling rate and the shape coefficient. The wind load shape coefficient in JEC127-1979 Japanese transmission line tower design specifications is mainly obtained through wind tunnel tests. The tower shape coefficient is divided into two categories: the front and rear oblique material overlap section and the non-overlap section. The filling rate is substituted into the formula for calculation, and the cross arm shape coefficient is considered as 90% of the tower shape coefficient. The calculation of the wind load shape coefficient of the IEC60826:2003 international standard for transmission lines is the same as that of the EU specification.

[0006] Through comparative analysis of wind load shape coefficient calculation formulas in various countries, it is found that the wind load shape coefficients of standard towers are all functions related to the filling rate. This method is a holistic concept, considering the entire section of the tower or part of the tower as a whole. However, the consideration of the factors affecting the calculation accuracy is too single, resulting in low calculation accuracy and poor applicability. Summary of the invention

[0007] In order to solve the shortcomings of the prior art, the present invention provides a method and system for calculating the shape coefficient of the wind load of an angle steel transmission tower, which fully considers the influencing factors that limit the calculation accuracy, provides a reference and basis for accurately calculating the wind load of the angle steel transmission tower, has broad application prospects, and solves the problems of low calculation accuracy and poor applicability caused by the excessively single influencing factors considered in the current standard calculation method.

[0008] In order to achieve the above-mentioned object of the invention, the present invention adopts the following technical scheme:

[0009] A method for calculating the wind load shape coefficient of an angle steel transmission tower includes:

[0010] Based on the pre-built full-scale wind tunnel test model of angle steel transmission tower segment, the wind load reduction factor on the leeward side of the angle steel tower is determined;

[0011] Based on the pre-established shape coefficient library of angle steel components at various wind direction angles, the wind load shape coefficient of the single truss on the windward side of the angle steel transmission tower segment is obtained, and the wind load shape coefficient of the single truss on the windward side of the angle steel transmission tower segment is corrected by using the normal wind angle adjustment coefficient;

[0012] The wind load shape coefficient of the angle steel tower is calculated based on the modified wind load shape coefficient of the single-piece truss on the windward side of the angle steel transmission tower segment and the wind load reduction coefficient on the leeward side of the angle steel tower.

[0013] Preferably, the determining of the leeward wind load reduction factor of the angle steel tower frame based on the pre-constructed full-scale wind tunnel test model of the angle steel transmission tower segment comprises:

[0014] Based on the pre-built full-scale wind tunnel test model of angle steel transmission tower segment, the wind load shape coefficients of the leeward and windward sides of the angle steel tower are determined;

[0015] According to the wind load shape coefficients of the leeward and windward sides of the angle steel tower, the wind load reduction coefficient of the leeward side of the angle steel tower is calculated.

[0016] Furthermore, obtaining the wind load shape coefficients of the leeward and windward surfaces of the angle steel tower includes:

[0017] Connect the windward side of the angle steel tower to a high-frequency force balance;

[0018] The leeward side is mounted on a sliding guide rail and is separated from the high-frequency force measuring balance;

[0019] Use a high-frequency force balance to measure the wind load shape coefficients of the windward and leeward sides of the angle steel tower; or,

[0020] Connect the leeward side of the angle steel tower to a high-frequency force balance;

[0021] The windward surface is mounted on a sliding guide rail for movement and is separated from the high-frequency force measuring balance;

[0022] A high-frequency force balance is used to measure the wind load shape coefficients of the windward and leeward sides of the angle steel tower.

[0023] Preferably, the leeward wind load reduction factor of the angle steel tower is determined by the following formula:

[0024] η=μ b / μ f

[0025] Where η is the wind load reduction factor on the leeward side of the angle steel tower, μ b , μ f They are the leeward wind load shape coefficient and the windward wind load shape coefficient of the angle steel tower respectively.

[0026] Furthermore, the wind load shape coefficient of the single-piece truss on the windward side of the angle steel transmission tower segment is obtained based on the pre-established shape coefficient library of angle steel components at various wind directions, including:

[0027] According to the spatial arrangement of the angle steel components on the windward side of the angle steel transmission tower segment in the wind load shape coefficient library, a table interpolation method is used to obtain the wind direction angle of the angle steel components and the wind load shape coefficient of the angle steel components on the single-piece truss on the windward side of the angle steel transmission tower segment;

[0028] Calculate the wind load shape coefficient of the single-piece truss on the windward side of the angle steel transmission tower segment according to the wind load shape coefficient of the angle steel component on the single-piece truss on the windward side of the angle steel transmission tower segment;

[0029] According to the wind load shape coefficient of the single-piece truss on the windward side of the angle steel transmission tower segment, the normal wind angle adjustment coefficient is defined; wherein the angle steel component includes cold-bent angle steel and hot-rolled angle steel.

[0030] Furthermore, the establishment of the shape coefficient library of the angle steel member at each wind direction angle includes:

[0031] Conduct wind tunnel tests on angle steel components using a pre-built full-scale wind tunnel test model of angle steel transmission tower segments; or conduct CFD numerical simulations on angle steel components;

[0032] The wind tunnel test results and CFD numerical simulation results are obtained to establish a wind load shape coefficient library for angle steel components at various wind directions.

[0033] Furthermore, the wind load shape coefficient of the single-piece truss on the windward side of the angle steel transmission tower segment is determined by the following formula:

[0034]

[0035] In the formula, is the weighted wind load shape coefficient of the single truss on the windward side of the angle steel transmission tower segment, C di is the wind load shape coefficient of the angle steel member on the windward side of the single truss of the angle steel transmission tower segment, A i is the effective projected area of ​​the i-th angle steel member in the angle steel tower.

[0036] Furthermore, the definition of the normal wind angle adjustment coefficient includes:

[0037] The angle between the normal wind direction of the windward single-piece truss and the airflow direction is defined as the normal wind angle β;

[0038] The wind load shape coefficient of the windward monolithic truss under different normal wind angles β is obtained based on full-scale model wind tunnel tests or CFD numerical simulations;

[0039] The normal wind angle adjustment coefficient λ under the normal wind angle β is defined as the ratio of the wind load shape coefficient of the windward single-piece truss under the normal wind angle β to the wind load shape coefficient of the windward single-piece truss under the normal wind angle 0°.

[0040] Preferably, the wind load shape coefficient of the single-piece truss on the windward side of the angle steel transmission tower segment is corrected by the following formula:

[0041]

[0042] In the formula, is the modified wind load shape coefficient of the single-piece truss on the windward side of the angle steel transmission tower segment, is the wind load shape coefficient of the single-piece truss on the windward side of the angle steel transmission tower segment, and λ is the normal wind angle adjustment coefficient.

[0043] Furthermore, the wind load shape coefficient of the angle steel tower is determined by the following formula:

[0044]

[0045] In the formula, C DT is the wind load shape coefficient of the angle steel tower, η is the wind load reduction coefficient on the leeward side of the angle steel tower, It is the modified wind load shape coefficient of the single-piece truss on the windward side of the angle steel transmission tower segment.

[0046] A wind load shape coefficient calculation system for an angle steel transmission tower, comprising:

[0047] The first calculation module is used to determine the leeward wind load reduction factor of the angle steel tower frame based on a pre-built full-scale wind tunnel test model of an angle steel transmission tower segment;

[0048] A correction module is used to obtain the wind load shape coefficient of the single truss on the windward side of the angle steel transmission tower segment based on a pre-established shape coefficient library of angle steel components at various wind direction angles, and to correct the wind load shape coefficient of the single truss on the windward side of the angle steel transmission tower segment by using a normal wind angle adjustment coefficient;

[0049] The second calculation module is used to calculate the wind load shape coefficient of the angle steel tower according to the modified wind load shape coefficient of the single-piece truss on the windward side of the angle steel transmission tower segment and the wind load reduction coefficient on the leeward side of the angle steel tower.

[0050] Compared with the closest prior art, the present invention has the following beneficial effects:

[0051] The present invention proposes a method and system for calculating the wind load shape coefficient of an angle steel transmission tower. Based on a pre-constructed full-scale wind tunnel test model of an angle steel transmission tower segment, the wind load reduction coefficient of the leeward side of the angle steel tower is determined; based on a pre-established library of shape coefficients of angle steel components at various wind direction angles, the wind load shape coefficient of the single-piece truss on the windward side of the angle steel transmission tower segment is obtained, and the wind load shape coefficient of the single-piece truss on the windward side of the angle steel transmission tower segment is corrected using the normal wind angle adjustment coefficient. The influencing factors that limit the calculation accuracy are fully considered: the influence of complex structural forms and irregular rod arrangements, the influence of airflow direction and angle steel placement direction, and the influence of the inclination of the single-piece truss on the windward side of the transmission angle steel tower segment. The application prospects are broad; the problem of low calculation accuracy and poor applicability caused by the excessively single influencing factors considered in the current standard calculation method is solved.

[0052] Finally, according to the revised wind load shape coefficient of the single-piece truss on the windward side of the angle steel transmission tower segment and the wind load reduction coefficient on the leeward side of the angle steel tower, the wind load shape coefficient of the angle steel tower is calculated, which provides a reference and basis for more accurate calculation of the wind load of the angle steel transmission tower, and effectively improves the accuracy of calculating the wind load of the angle steel transmission tower. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 A flow chart of a method for calculating the wind load shape coefficient of an angle steel transmission tower provided in a specific embodiment of the present invention;

[0054] FIG2 is an angle steel model provided in a specific embodiment of the present invention;

[0055] In the figure: (a) is cold-bent angle steel, (b) is hot-rolled angle steel;

[0056] FIG3 is a schematic diagram of wind direction angles provided in a specific embodiment of the present invention;

[0057] In the figure: (a) is a diagram illustrating the spatial position of the wind direction angle α, and (b) is an example of a typical wind direction angle;

[0058] Figure 4 A schematic diagram of normal wind angle provided for a specific embodiment of the present invention;

[0059] Figure 5 A typical angle steel transmission tower tower segment construction drawing provided for a specific embodiment of the present invention;

[0060] In the figure: ①② are the main materials of the tower body, ③④ are the diagonal materials of the tower body, ⑤⑥⑦⑧⑨⑩ are the auxiliary materials of the tower body. DETAILED DESCRIPTION

[0061] The present invention will be further described in detail below in conjunction with the accompanying drawings.

[0062] The present invention aims at the three deficiencies of the current standard angle steel transmission tower wind load body shape coefficient calculation method: first, the current standard only considers the filling coefficient, and cannot consider the influence of complex structural forms and irregular rod arrangement; second, it cannot consider the influence of airflow direction and angle steel placement direction; third, it cannot consider the influence of the inclination of the single truss on the windward side of the transmission angle steel tower segment. And, based on the above three deficiencies, the accuracy of the angle steel transmission tower wind load calculated according to the current standard needs to be improved, and a method for calculating the wind load body shape coefficient of the angle steel transmission tower is proposed.

[0063] This method first gives a method for determining the wind load reduction coefficient η on the leeward side of the angle steel tower based on the full-scale model wind tunnel test according to the wind tunnel test results; the shape coefficient library of the angle steel rod under different wind directions is determined based on the full-scale model wind tunnel test or CFD numerical simulation; according to the spatial arrangement characteristics of the angle steel components on the windward side of the angle steel transmission tower segment, the shape coefficient of the windward side of the angle steel transmission tower segment is given based on the shape coefficient library of the angle steel components under different wind directions; considering the influence of the inclination of the single-piece truss on the windward side of the transmission angle steel tower segment, the normal wind angle adjustment coefficient λ is proposed, and the wind load shape coefficient of the single-piece truss on the windward side of the angle steel transmission tower segment considering the correction of the normal wind angle is given; finally, a method for calculating the wind load shape coefficient of the angle steel transmission tower segment based on the angle steel wind load shape coefficient is proposed, which provides a reference and basis for more accurate calculation of the wind load of the angle steel transmission tower.

[0064] Compared with the traditional method of calculating the wind load shape coefficient of angle steel transmission towers, this method solves the problems that the current standard calculation method cannot consider the influence of complex structural forms and irregular rod arrangements, cannot consider the influence of airflow direction and angle steel placement direction, and cannot consider the influence of the inclination of the single-piece truss on the windward side of the transmission angle steel tower segment. It has better applicability.

[0065] like Figure 1 As shown, the method for calculating the wind load shape coefficient of the angle steel transmission tower provided by the present invention comprises the following steps:

[0066] S1 determines the leeward wind load reduction factor of the angle steel tower based on the pre-built full-scale wind tunnel test model of the angle steel transmission tower segment;

[0067] S2 obtains the wind load shape coefficient of the single truss on the windward side of the angle steel transmission tower segment based on the pre-established shape coefficient library of angle steel components at various wind direction angles, and uses the normal wind angle adjustment coefficient to correct the wind load shape coefficient of the single truss on the windward side of the angle steel transmission tower segment;

[0068] S3 calculates the wind load shape coefficient of the angle steel tower frame according to the modified wind load shape coefficient of the single-piece truss on the windward side of the angle steel transmission tower segment and the wind load reduction coefficient on the leeward side of the angle steel tower frame.

[0069] In step S1, based on the pre-constructed full-scale wind tunnel test model of the angle steel transmission tower segment, the leeward wind load reduction factor of the angle steel tower frame is determined, including:

[0070] Based on the pre-built full-scale wind tunnel test model of angle steel transmission tower segment, the wind load shape coefficients of the leeward and windward sides of the angle steel tower are determined;

[0071] According to the wind load shape coefficients of the leeward and windward sides of the angle steel tower, the wind load reduction coefficient of the leeward side of the angle steel tower is calculated.

[0072] Among them, based on the pre-built full-scale wind tunnel test model of the angle steel transmission tower segment, the wind load shape coefficients of the leeward and windward sides of the angle steel tower are determined, including:

[0073] Design a full-scale wind tunnel test model of the angle steel transmission tower segment according to the angle steel transmission tower structure construction drawing, connect the windward side of the angle steel tower frame to the high-frequency force measuring balance; install the leeward side on the sliding guide rail and move it, and separate it from the high-frequency force measuring balance; use the high-frequency force measuring balance to measure the wind load shape coefficients of the windward side and the leeward side of the angle steel tower frame respectively; or,

[0074] Connect the leeward side of the angle steel tower to a high-frequency force balance;

[0075] The windward surface is mounted on a sliding guide rail for movement and is separated from the high-frequency force measuring balance;

[0076] A high-frequency force balance is used to measure the wind load shape coefficients of the windward and leeward sides of the angle steel tower.

[0077] In addition, the leeward wind load reduction factor of the angle steel tower is determined by the following formula:

[0078] η=μ b / μ f

[0079] Where η is the wind load reduction factor on the leeward side of the angle steel tower, μ b , μ f They are the leeward wind load shape coefficient and the windward wind load shape coefficient of the angle steel tower respectively.

[0080] In step S2, the establishment of the shape coefficient library of angle steel components under different wind directions includes:

[0081] Conduct wind tunnel tests on angle steel components using a pre-built full-scale wind tunnel test model of angle steel transmission tower segments; or conduct CFD numerical simulations on angle steel components;

[0082] The wind tunnel test results and CFD numerical simulation results are obtained to establish a wind load shape coefficient library for angle steel components at various wind directions.

[0083] For example, two types of angle steels, cold-bent angle steel (Figure 2(a)) and hot-rolled angle steel (Figure 2(b)), are selected to establish a body coefficient library under different wind directions. In the figure, the limb length is recorded as b, and the limb thickness is recorded as t. The angle between the airflow direction and the symmetry axis of the angle steel is defined as the wind direction angle α, as shown in Figure 3(a).

[0084] Based on full-scale model wind tunnel tests or CFD numerical simulations, the wind load body shape coefficient library of cold-bent angle steel and hot-rolled angle steel at different wind directions is obtained. The wind direction angle range is 0° to 180°, and every 10° is a wind direction angle. In addition, it also includes two typical wind directions of 45° and 135°. The wind load body shape coefficient library is shown in Table 1:

[0085] Table 1 Wind load shape coefficient

[0086]

[0087]

[0088] The wind load shape coefficient of angle steel components can be obtained by interpolation from the table.

[0089] Step S2, based on the shape coefficient library of angle steel components under different wind directions, obtains the wind load shape coefficient of the single-piece truss on the windward side of the angle steel transmission tower segment and the corresponding normal wind angle adjustment coefficient, including:

[0090] a. According to the spatial arrangement of angle steel components on the windward side of the angle steel transmission tower segment in the wind load body shape coefficient library, the wind direction angle of the angle steel components and the wind load body shape coefficient of the angle steel components on the single-piece truss on the windward side of the angle steel transmission tower segment are obtained by using the table interpolation method; in general, the wind direction angle of the angle steel components with the back of the limb facing outward is 135°, and the wind direction angle of the angle steel components with the tip of the limb facing outward is 45°.

[0091] b. Calculate the wind load shape coefficient of the single truss on the windward side of the angle steel transmission tower segment according to the wind load shape coefficient of the angle steel member on the single truss on the windward side of the angle steel transmission tower segment;

[0092] c. Define the normal wind angle adjustment coefficient based on the wind load shape coefficient of the single-piece truss on the windward side of the angle steel transmission tower segment.

[0093] The effective projected area of ​​the i-th angle steel member in a tower is A i , then the following formula can be used to calculate the weighted wind load shape coefficient of the single truss on the windward side of the angle steel transmission tower segment:

[0094]

[0095] In the formula, is the weighted wind load shape coefficient of the single truss on the windward side of the angle steel transmission tower segment, C di is the wind load shape coefficient of the angle steel member on the windward side of the single truss of the angle steel transmission tower segment, A i is the effective projected area of ​​the i-th angle steel member in the angle steel tower.

[0096] In step c, defining the normal wind angle adjustment coefficient includes:

[0097] The angle between the normal wind direction of the windward single-piece truss and the airflow direction is defined as the normal wind angle β, as follows: Figure 4 shown.

[0098] The wind load shape coefficient of the windward monolithic truss under different normal wind angles β is obtained based on full-scale model wind tunnel tests or CFD numerical simulations;

[0099] The normal wind angle adjustment coefficient λ under the normal wind angle β is defined as the ratio of the wind load shape coefficient of the windward single-piece truss under the normal wind angle β to the wind load shape coefficient of the windward single-piece truss under the normal wind angle 0°.

[0100] The normal wind angle of the single-piece truss on the windward side of the transmission angle steel tower is generally within 0 to 20 degrees. Combined with the full-scale model wind tunnel test or CFD numerical simulation results, the adjustment coefficient λ of the normal wind angle of 0 to 10 degrees is taken as 0.98, and the adjustment coefficient λ of the normal wind angle of 10 to 20 degrees is taken as 0.96.

[0101] Step S2, correcting the wind load shape coefficient of the single-piece truss on the windward side of the angle steel transmission tower segment by the following formula:

[0102]

[0103] In the formula, is the modified wind load shape coefficient of the single-piece truss on the windward side of the angle steel transmission tower segment, is the wind load shape coefficient of the single-piece truss on the windward side of the angle steel transmission tower segment, and λ is the normal wind angle adjustment coefficient.

[0104] Step S3 determines the wind load shape coefficient of the angle steel tower by the following formula:

[0105]

[0106] In the formula, C DT is the wind load shape coefficient of the angle steel tower, η is the wind load reduction coefficient on the leeward side of the angle steel tower, It is the modified wind load shape coefficient of the single-piece truss on the windward side of the angle steel transmission tower segment.

[0107] Example

[0108] The application of a specific example introduces the process of calculating the wind load shape coefficient of an angle steel transmission tower using the above method:

[0109] Take a 500kV transmission line angle steel transmission tower as an example. Figure 4 :The specifications of the main material, diagonal material and auxiliary material of the tower body in this section are L180×14, L100×7 and L40×4 respectively. The wind direction angle of the angle steel components of ①②④⑤⑦⑨ is 135°, and the wind direction angle of the angle steel components of ③⑥⑧⑩ is 45°

[0110] First, according to the method of step S1, a full-scale wind tunnel test model of the angle steel transmission tower segment is designed according to the construction drawing of the angle steel transmission tower segment shown in Figure 3, and the windward side or the leeward side of the angle steel tower frame is connected to the high-frequency force measuring balance separately, and the other side is installed on the sliding guide rail for movement, and the side is separated from the high-frequency force measuring balance, and the leeward side wind load body shape coefficient μ is measured respectively. b and the windward wind load shape coefficient μ f The wind load reduction factor η on the leeward side of the angle steel tower is calculated by the following formula.

[0111] η=μ b / μ f =0.84 / 1.40=0.60

[0112] According to the method of steps S2-S3, the wind load shape coefficient library of cold-bent angle steel and hot-rolled angle steel under different wind directions is obtained based on the full-scale model wind tunnel test or CFD numerical simulation, and the wind load shape coefficient of each rod is obtained from the database

[0113] Table 2 Wind load shape coefficients of each member

[0114]

[0115]

[0116] According to the method in step S3, the projected areas of the various components are shown in Table 3.

[0117] Table 3 Projection area of ​​each member

[0118] Rod No. <![CDATA[Projected area A of the component i > 1 0.5 2 0.5 3 0.48 4 0.48 5 0.04 6 0.048 7 0.048 8 0.048 9 0.048 10 0.04

[0119] The weighted wind load shape coefficient of the single truss on the windward side of the angle steel transmission tower segment is calculated

[0120]

[0121] According to the method in step S3, the normal wind angle adjustment coefficient λ is determined to be 0.98.

[0122] According to the method in step S4, calculate the wind load shape coefficient of the single-piece truss on the windward side of the angle steel transmission tower segment considering the correction of the normal wind angle

[0123]

[0124] According to the method in step S5, the wind load shape coefficient of the steel tube transmission tower is calculated. According to steps S2 and S4, the wind load reduction coefficient correction factor η of the leeward side of the steel tube transmission tower and the weighted wind load shape coefficient of the single truss corrected by considering the normal wind angle are obtained respectively. Calculation of wind load shape factor C of steel tube transmission tower DT =1.753×(1+0.6)=2.805.

[0125] Based on the same inventive concept, the present application also proposes a system for calculating the wind load shape coefficient of an angle steel transmission tower, comprising:

[0126] The first calculation module is used to determine the leeward wind load reduction factor of the angle steel tower frame based on a pre-built full-scale wind tunnel test model of an angle steel transmission tower segment;

[0127] A correction module is used to obtain the wind load shape coefficient of the single truss on the windward side of the angle steel transmission tower segment based on a pre-established shape coefficient library of angle steel components at various wind direction angles, and to correct the wind load shape coefficient of the single truss on the windward side of the angle steel transmission tower segment by using a normal wind angle adjustment coefficient;

[0128] The second calculation module is used to calculate the wind load shape coefficient of the angle steel tower according to the modified wind load shape coefficient of the single-piece truss on the windward side of the angle steel transmission tower segment and the wind load reduction coefficient on the leeward side of the angle steel tower.

[0129] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

[0130] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0131] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0132] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

Claims

1. A method for calculating the wind load shape coefficient of an angle steel transmission tower, characterized in that: include: Based on the pre-built full-scale wind tunnel test model of angle steel transmission tower segment, the wind load reduction factor on the leeward side of the angle steel tower is determined; Based on the pre-established shape coefficient library of angle steel components at various wind direction angles, the wind load shape coefficient of the single truss on the windward side of the angle steel transmission tower segment is obtained, and the wind load shape coefficient of the single truss on the windward side of the angle steel transmission tower segment is corrected by using the normal wind angle adjustment coefficient; The wind load shape coefficient of the angle steel tower is calculated according to the modified wind load shape coefficient of the single-piece truss on the windward side of the angle steel transmission tower segment and the wind load reduction coefficient on the leeward side of the angle steel tower; The method for determining the leeward wind load reduction factor of the angle steel tower frame based on the pre-constructed full-scale wind tunnel test model of the angle steel transmission tower segment includes: Based on the pre-built full-scale wind tunnel test model of angle steel transmission tower segment, the wind load shape coefficients of the leeward and windward sides of the angle steel tower are determined; According to the wind load shape coefficients of the leeward and windward sides of the angle steel tower, calculate the wind load reduction coefficient of the leeward side of the angle steel tower; The leeward wind load reduction factor of the angle steel tower is determined by the following formula: h=m b / m f Where η is the wind load reduction factor on the leeward side of the angle steel tower, μ b , μ f They are the leeward wind load shape coefficient and the windward wind load shape coefficient of the angle steel tower respectively; The wind load shape coefficient of the single-piece truss on the windward side of the angle steel transmission tower segment is obtained based on the pre-established shape coefficient library of angle steel components at various wind directions, including: According to the spatial arrangement of the angle steel components on the windward side of the angle steel transmission tower segment in the shape coefficient library, a table interpolation method is used to obtain the wind direction angle of the angle steel components and the wind load shape coefficient of the angle steel components on the single-piece truss on the windward side of the angle steel transmission tower segment; Calculate the wind load shape coefficient of the single-piece truss on the windward side of the angle steel transmission tower segment according to the wind load shape coefficient of the angle steel component on the single-piece truss on the windward side of the angle steel transmission tower segment; According to the wind load shape coefficient of the single-piece truss on the windward side of the angle steel transmission tower segment, a normal wind angle adjustment coefficient is defined; wherein the angle steel component includes cold-bent angle steel and hot-rolled angle steel; The establishment of the shape coefficient library of the angle steel component under various wind directions includes: Conduct wind tunnel tests on angle steel components using a pre-built full-scale wind tunnel test model of angle steel transmission tower segments; or conduct CFD numerical simulations on angle steel components; Obtain wind tunnel test results and CFD numerical simulation results, and establish a wind load shape coefficient library for angle steel components at various wind directions; The wind load shape coefficient of the single-piece truss on the windward side of the angle steel transmission tower segment is determined by the following formula: In the formula, is the wind load shape coefficient of the single truss on the windward side of the angle steel transmission tower segment, C di is the wind load shape coefficient of the angle steel member on the windward side of the single truss of the angle steel transmission tower segment, A i is the effective projected area of ​​the i-th angle steel member in the angle steel tower; The wind load shape coefficient of the single-piece truss on the windward side of the angle steel transmission tower segment is corrected by the following formula: In the formula, is the modified wind load shape coefficient of the single-piece truss on the windward side of the angle steel transmission tower segment, is the wind load shape coefficient of the single-piece truss on the windward side of the angle steel transmission tower segment, and λ is the normal wind angle adjustment coefficient; The wind load shape factor of the angle steel tower is determined by the following formula: In the formula, C DT is the wind load shape coefficient of the angle steel tower, η is the wind load reduction coefficient on the leeward side of the angle steel tower, It is the modified wind load shape coefficient of the single-piece truss on the windward side of the angle steel transmission tower segment.

2. The method according to claim 1, characterized in that Obtaining the wind load shape coefficients of the leeward and windward sides of the angle steel tower includes: Connect the windward side of the angle steel tower to a high-frequency force balance; The leeward side is mounted on a sliding guide rail and is separated from the high-frequency force measuring balance; Use a high-frequency force balance to measure the wind load shape coefficients of the windward and leeward sides of the angle steel tower; or, Connect the leeward side of the angle steel tower to a high-frequency force balance; The windward surface is mounted on a sliding guide rail for movement and is separated from the high-frequency force measuring balance; A high-frequency force balance is used to measure the wind load shape coefficients of the windward and leeward sides of the angle steel tower.

3. The method according to claim 1, characterized in that The definition of the normal wind angle adjustment coefficient includes: The angle between the normal wind direction of the windward single-piece truss and the airflow direction is defined as the normal wind angle β; The wind load shape coefficient of the windward monolithic truss under different normal wind angles β is obtained based on full-scale model wind tunnel tests or CFD numerical simulations; The normal wind angle adjustment coefficient λ under the normal wind angle β is defined as the ratio of the wind load shape coefficient of the windward single-piece truss under the normal wind angle β to the wind load shape coefficient of the windward single-piece truss under the normal wind angle 0°.

4. A system for calculating the wind load shape coefficient of an angle steel transmission tower, characterized in that: include: The first calculation module is used to determine the leeward wind load reduction factor of the angle steel tower frame based on a pre-built full-scale wind tunnel test model of an angle steel transmission tower segment; A correction module is used to obtain the wind load shape coefficient of the single truss on the windward side of the angle steel transmission tower segment based on a pre-established shape coefficient library of angle steel components at various wind direction angles, and to correct the wind load shape coefficient of the single truss on the windward side of the angle steel transmission tower segment by using a normal wind angle adjustment coefficient; The second calculation module is used to calculate the wind load shape coefficient of the angle steel tower frame according to the corrected wind load shape coefficient of the single-piece truss on the windward side of the angle steel transmission tower segment and the wind load reduction coefficient on the leeward side of the angle steel tower frame; The first calculation module is specifically used for: Based on the pre-built full-scale wind tunnel test model of angle steel transmission tower segment, the wind load shape coefficients of the leeward and windward sides of the angle steel tower are determined; According to the wind load shape coefficients of the leeward and windward sides of the angle steel tower, calculate the wind load reduction coefficient of the leeward side of the angle steel tower; Among them, the leeward wind load reduction factor of the angle steel tower is determined by the following formula: h=m b / m f Where η is the wind load reduction factor on the leeward side of the angle steel tower, μ b , μ f They are the leeward wind load shape coefficient and the windward wind load shape coefficient of the angle steel tower respectively; The correction module obtains the wind load shape coefficient of the single-piece truss on the windward side of the angle steel transmission tower segment based on the pre-established shape coefficient library of angle steel components at various wind directions, which is specifically used for: According to the spatial arrangement of the angle steel components on the windward side of the angle steel transmission tower segment in the shape coefficient library, a table interpolation method is used to obtain the wind direction angle of the angle steel components and the wind load shape coefficient of the angle steel components on the single-piece truss on the windward side of the angle steel transmission tower segment; Calculate the wind load shape coefficient of the single-piece truss on the windward side of the angle steel transmission tower segment according to the wind load shape coefficient of the angle steel component on the single-piece truss on the windward side of the angle steel transmission tower segment; According to the wind load shape coefficient of the single-piece truss on the windward side of the angle steel transmission tower segment, a normal wind angle adjustment coefficient is defined; wherein the angle steel component includes cold-bent angle steel and hot-rolled angle steel; The specific steps for establishing the shape coefficient library of the angle steel component under various wind directions are as follows: Conduct wind tunnel tests on angle steel components using a pre-built full-scale wind tunnel test model of angle steel transmission tower segments; or conduct CFD numerical simulations on angle steel components; Obtain wind tunnel test results and CFD numerical simulation results, and establish a wind load shape coefficient library for angle steel components at various wind directions; The wind load shape coefficient of the single-piece truss on the windward side of the angle steel transmission tower segment is determined by the following formula: In the formula, is the wind load shape coefficient of the single truss on the windward side of the angle steel transmission tower segment, C di is the wind load shape coefficient of the angle steel member on the windward side of the single truss of the angle steel transmission tower segment, A i is the effective projected area of ​​the i-th angle steel member in the angle steel tower; The wind load shape coefficient of the single-piece truss on the windward side of the angle steel transmission tower segment is corrected by the following formula: In the formula, is the modified wind load shape coefficient of the single-piece truss on the windward side of the angle steel transmission tower segment, is the wind load shape coefficient of the single-piece truss on the windward side of the angle steel transmission tower segment, and λ is the normal wind angle adjustment coefficient; The second calculation module determines the wind load shape coefficient of the angle steel tower by the following formula: In the formula, C DT is the wind load shape coefficient of the angle steel tower, η is the wind load reduction coefficient on the leeward side of the angle steel tower, It is the modified wind load shape coefficient of the single-piece truss on the windward side of the angle steel transmission tower segment.

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