Bridge vortex vibration early warning method and system based on vortex field monitoring

Abstract

The invention discloses a bridge vortex vibration early warning method and system based on vortex field monitoring. The system comprises a wind field acquisition subsystem, a vorticity calculation and prediction subsystem and a vortex field analysis and early warning subsystem. The wind field acquisition subsystem is used for monitoring wind speeds and wind directions of different space points around the main beam in real time. And the vorticity calculation and prediction subsystem calculates the wind speed and wind direction space point data acquired by the wind field acquisition subsystem in real time to obtain the vorticity value around the main beam, and predicts the vorticity value at the future moment. And the vortex field analysis and early warning subsystem performs frequency domain analysis on a vorticity time history, monitors and predicts vortex intensity and vortex shedding frequency in real time, and gives an early warning before vortex vibration possibly occurs. The system can give an alarm in real time according to a vortex vibration mechanism and can play a role in early warning in advance.

Description

Technical Field

[0001] The present invention belongs to the field of wind resistance of long-span bridges in civil engineering, relates to real-time identification of eddy current fields of long-span bridges and early warning of vortex vibration of main beams, and specifically relates to a bridge vortex vibration warning method and system based on eddy current field monitoring. Background Art

[0002] In recent years, many cities and regions at home and abroad have completed a series of magnificent bridge projects, including masterpieces that use advanced structural designs such as cable-stayed bridges and suspension bridges. While these large bridges improve traffic efficiency, they also face increasingly severe wind load challenges. As the span of the bridge continues to extend, its structural flexibility increases significantly, and the problem of wind-induced vibration becomes increasingly prominent, becoming a key factor affecting the safe operation of the bridge.

[0003] Wind disasters, as one of the most frequent natural disasters, pose a serious threat to human life and property safety. According to statistics, the global losses caused by wind disasters reach 10 billion US dollars each year, and the average annual death toll is more than 20,000. Therefore, wind disasters have brought great harm to human life and property. More than 70 years after the flutter and wind damage accident of the Tacoma Suspension Bridge in the United States, wind-induced vibration of bridges has long attracted the attention of bridge engineers from all over the world. With the continuous deepening of bridge wind engineering research, wind-induced bridge vibration has become a hot topic that has attracted much attention.

[0004] Among them, vortex vibration is caused by the vortex shedding caused by gas flowing around the surface. When the vortex shedding frequency is close to the natural frequency of the structure, resonance and fluid-solid coupling occur, thus generating vortex vibration. Although it usually does not cause the structure to lose dynamic stability immediately, excessive vibration amplitude may have an adverse effect on pedestrian comfort, driving safety and fatigue life of components, and even cause public panic. Many large bridges around the world have encountered vortex vibration problems, such as China's Humen Bridge, South Korea's new and old Jindo Bridges, and the UK's Second Severn Bridge.

[0005] At present, bridge vortex vibration monitoring mainly realizes real-time monitoring of bridge operation status through bridge wind field environment monitoring and structural response monitoring. The existing monitoring system only involves the wind field conditions that induce vortex vibration and the structural response of the bridge after vortex vibration occurs, but lacks monitoring of the eddy current field that directly causes vortex vibration. The purpose of the present invention is to complete the monitoring of vortex current field in the process of vortex vibration "incoming flow-vortex shedding-excitation" and issue an early warning before vortex vibration starts. Summary of the invention

[0006] To solve the above problems, the present invention discloses a bridge vortex vibration early warning method and system based on eddy current field monitoring, which can realize real-time early warning and online measurement of vortex vibration, with small data volume, low calculation pressure and high calculation efficiency, and is suitable for all large-span bridges.

[0007] To achieve the above object, the technical solution of the present invention is as follows:

[0008] A bridge vortex vibration early warning system based on eddy current field monitoring includes a wind field acquisition subsystem, a vortex volume calculation and prediction subsystem, and an eddy current field analysis and early warning subsystem.

[0009] Among them, the wind field acquisition subsystem is used to monitor the wind speed and wind direction at different spatial points around the main beam in real time; the vortex calculation and prediction subsystem is used to perform real-time calculations on the wind speed and wind direction spatial point data collected by the wind field acquisition subsystem to obtain the vortex value around the main beam; the eddy field analysis and early warning subsystem is used to perform frequency domain analysis on the vortex time series, monitor the vortex intensity and vortex shedding frequency in real time, and issue an early warning before vortex vibration may occur.

[0010] The wind field collection subsystem includes a wind field collection device and a collection device layout plan. Each wind field collection device includes a wind speed and direction sensor and two unidirectional wind speed sensors: the wind speed and direction sensor is used to measure the vertical wind speed and the lateral wind speed; the unidirectional wind speed sensor is placed at the vertical and lateral distance D of the wind speed and direction sensor, the vertical offset sensor measures the lateral wind speed, and the lateral offset sensor measures the vertical wind speed.

[0011] The collection device layout plan is to set up a total of 6 collection devices around the main beam, with one collection device extending from each side of the main beam to measure the incoming wind field and the tail vortex behind the main beam; 2 collection devices are set on the bridge deck and 2 collection devices are set at the bottom of the beam to measure the attached vortices above and below the main beam; a total of 12 collection devices are set around the truss beam, and the setting method of the upper and lower bridge decks is similar to that of the box beam.

[0012] The vorticity calculation and prediction subsystem includes a vorticity calculation module and a vorticity prediction module; the vorticity calculation module performs real-time calculation on the wind speed and direction data collected by the wind field collection device to obtain a vorticity value based on the curl. The curl calculation formula is as follows:

[0013]

[0014] In actual situations, Δv is used instead of Δx instead Δy instead get

[0015]

[0016] In this system:

[0017]

[0018] Where ω(x, y) is the vortex curl at the wind speed and direction sensor, v x(x, y) and v y (x, y) are the lateral wind speed and vertical wind speed measured by the wind speed and direction sensor, v x (x, y+D) is the lateral wind speed measured by the unidirectional wind speed sensor at a vertical distance D from the wind speed and direction sensor, v y (x+D, y) is the vertical wind speed measured by the unidirectional wind speed sensor at a lateral distance D from the wind speed and direction sensor. The positive or negative value of D is determined by the sensor layout position.

[0019] The vorticity prediction module uses historical measured data as training samples and trains the prediction subsystem based on the LSTM method. The prediction subsystem uses real-time vorticity data for prediction to obtain the vorticity value and change trend of the measuring point in the future.

[0020] The eddy current field analysis and early warning subsystem includes an eddy current field analysis module and a vortex vibration early warning module.

[0021] The eddy current field analysis module performs frequency domain analysis on the vorticity of each measuring point to obtain the vorticity of each point, the frequency of vorticity change, and the phase difference between measuring points B-1 (B'-1) and B-2 (B'-2), C-1 (C'-1) and C-2 (C'-2);

[0022] The function of the vortex vibration warning module is to issue a vortex vibration warning when the results of the eddy current field analysis module reach certain data, as follows:

[0023] (1) The vorticity value of A-1 (A'-1) or A-2 (A'-2) (leeward side measurement point) is large, and the frequency is close to the vertical bending frequency of the main beam, and a vertical bending vortex vibration warning is issued;

[0024] (2) The vorticity value of A-1 (A'-1) or A-2 (A'-2) (leeward side measurement point) is large, and the frequency is close to the main beam torsion frequency, and a torsional vortex vibration warning is issued;

[0025] (3) The phase difference between B-1 (B'-1) and B-2 (B'-2), C-1 (C'-1) and C-2 (C'-2) is about π / 2, and the frequency of change is close to the torsional frequency of the main beam, which issues a torsional vortex vibration warning;

[0026] (4) For bridges with complex structures such as truss beams, it is necessary to analyze the overall vortex distribution status based on the data from all measurement points on the entire bridge.

[0027] The beneficial effects of the present invention are:

[0028] 1) The process of the present invention is simple. The eddy current field around the main beam can be obtained by simply processing the wind speed, and the eddy current field that excites the vortex vibration of the bridge can be quickly found. The data volume is small, the calculation pressure is small, and the calculation efficiency is high. The real-time early warning and online measurement of vortex vibration can be realized, and the sustainable and stable operation can be achieved;

[0029] 2) The present invention can be combined with the existing health monitoring system of the bridge to form a full-process monitoring and early warning of incoming flow, eddy current field, vibration response, and vortex vibration;

[0030] 3) The present invention has a wide range of application scenarios and is suitable for all long-span bridges. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A flow chart of a bridge vortex vibration early warning method and system based on eddy current field monitoring of the present application;

[0032] Figure 2 This is a structural schematic diagram of a bridge vortex vibration early warning method based on eddy current field monitoring and a wind field acquisition device in the system of the present application, in which: 1. wind speed and direction sensor; 2. vertical wind speed sensor; 3. lateral wind speed sensor; 4. fixing bracket;

[0033] Figure 3 Schematic diagram of the layout of the bridge vortex-vibration early warning method and the collection device in the system based on eddy current field monitoring of the present application, (a) is the cross-sectional layout of the steel box girder, and (b) is the cross-sectional layout of the upper and lower truss beams. DETAILED DESCRIPTION

[0034] The present invention will be further explained below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the following specific embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0035] As shown in the figure, a bridge vortex vibration early warning system based on eddy current field monitoring described in the present invention includes a wind field acquisition subsystem, a vortex calculation and prediction subsystem, and an eddy current field analysis and early warning subsystem. The wind field acquisition subsystem is used to monitor the wind speed and wind direction at different spatial points around the main beam in real time. The vortex calculation and prediction subsystem is used to perform real-time calculations on the wind speed and wind direction spatial point data collected by the wind field acquisition subsystem, obtain the vortex value around the main beam, and predict the vortex value at future times. The eddy current field analysis and early warning subsystem is used to perform frequency domain analysis on the vortex time history, monitor and predict the vortex intensity and vortex shedding frequency in real time, and issue an early warning before vortex vibration may occur.

[0036] A bridge vortex vibration early warning method based on eddy current field monitoring, the steps of which are as follows:

[0037] S1, perform CFD simulation on the flow field around the main beam to obtain the vortex distribution around the main beam when the main beam has vortex vibration, and optimize the arrangement of the sensor's measuring point position according to the vortex cloud map, such as Figure 3 The eddy current wind field data collected by the wind direction and wind speed data acquisition instrument are vector-decomposed into the transverse wind speed and the vertical wind speed.

[0038] S2, using the vorticity calculation and prediction subsystem to calculate the vorticity of the wind field data collected by the wind field collection subsystem, taking the vorticity value based on the curl as the standard, the curl calculation formula is as follows:

[0039]

[0040] In actual situations, Δv is used instead of Δx instead Δy instead get

[0041]

[0042] In this system:

[0043]

[0044] Where ω(x, y) is the vortex curl at the wind speed and direction sensor, v x (x, y) and v y (x, y) are the lateral wind speed and vertical wind speed measured by the wind speed and direction sensor, v x (x, y+D) is the lateral wind speed measured by the unidirectional wind speed sensor at a vertical distance D from the wind speed and direction sensor, v y (x+D, y) is the vertical wind speed measured by the unidirectional wind speed sensor at a lateral distance D from the wind speed and direction sensor. The positive or negative value of D is determined by the sensor layout position.

[0045] The vorticity prediction module uses historical measured data as training samples and trains the prediction subsystem based on the LSTM method. The prediction subsystem uses real-time vorticity data for prediction to obtain the vorticity value and change trend of the measuring point in the future.

[0046] S3, the eddy current field analysis and warning subsystem performs frequency domain analysis on the vorticity of each measuring point to obtain the vorticity of each point, the frequency of vorticity change, the phase difference between B-1 (B'-1) and B-2 (B'-2), C-1 (C'-1) and C-2 (C'-2). When the eddy current field analysis module results show a certain data, a vortex vibration warning is issued. The data and warning are as follows:

[0047] (1) The vorticity value of A-1 (A'-1) or A-2 (A'-2) (leeward side measurement point) is large, and the frequency is close to the vertical bending frequency of the main beam, and a vertical bending vortex vibration warning is issued;

[0048] (2) The vorticity value of A-1 (A'-1) or A-2 (A'-2) (leeward side measurement point) is large, and the frequency is close to the main beam torsion frequency, and a torsional vortex vibration warning is issued;

[0049] (3) The phase difference between B-1 (B'-1) and B-2 (B'-2), C-1 (C'-1) and C-2 (C'-2) is about π / 2, and the frequency of change is close to the torsional frequency of the main beam, which issues a torsional vortex vibration warning;

[0050] (4) For bridges with complex structures such as truss beams, it is necessary to analyze the overall vortex distribution status based on the data from all measurement points on the entire bridge.

[0051] The present invention is based on wind speed measurement at different spatial points to achieve real-time monitoring of the eddy current field around the main beam, and can directly monitor the attached vortex and tail vortex that induce the vortex vibration of the bridge, thus completing the link of exciting resonance in the vortex vibration monitoring of the bridge, and can realize vortex vibration early warning before the occurrence of structural response.

Claims

1. A bridge vortex vibration early warning system based on eddy current field monitoring, characterized by: It includes wind field acquisition subsystem, vortex calculation and prediction subsystem, eddy field analysis and early warning subsystem; The wind field acquisition subsystem is used to monitor the wind speed and wind direction at different spatial points around the main beam in real time; The vorticity calculation and prediction subsystem is used to perform real-time calculation on the wind speed and wind direction spatial point data collected by the wind field collection subsystem, obtain the vorticity value around the main beam, and predict the vorticity value at a future time; The eddy current field analysis and early warning subsystem is used to perform frequency domain analysis on the vortex time history, monitor and predict the eddy current intensity and vortex shedding frequency in real time, and issue an early warning before vortex vibration may occur.

2. The bridge vortex vibration early warning system based on eddy current field monitoring according to claim 1 is characterized by: The wind field collection subsystem includes a wind field collection device and a collection device layout plan.

3. The bridge vortex vibration early warning system based on eddy current field monitoring according to claim 2 is characterized by: Each wind field collection device includes 1 wind speed and direction sensor and 2 unidirectional wind speed sensors; The wind speed and direction sensor is used to measure the vertical wind speed and the lateral wind speed; The two unidirectional wind speed sensors are respectively placed at a vertical and horizontal distance D from the wind speed and direction sensor.

4. The bridge vortex vibration early warning system based on eddy current field monitoring according to claim 2 is characterized by: The arrangement scheme of the collection device and the measuring point positions are optimized according to the CFD simulation results, and are arranged at the vortex shedding point, the attachment point and the tail vortex occurrence point to collect the wind field information of the vortex.

5. The bridge vortex vibration early warning system based on eddy current field monitoring according to claim 2 is characterized by: According to the arrangement scheme of the collection devices, a total of 6 collection devices are arranged around the box girder, wherein one collection device extends out from each side of the main girder, two collection devices are arranged on the bridge deck, and two collection devices are arranged at the bottom of the girder; a total of 12 collection devices are arranged around the truss girder, wherein the arrangement method of the upper and lower bridge decks is similar to that of the box girder.

6. The bridge vortex vibration early warning system based on eddy current field monitoring according to claim 2 is characterized by: The collection device arrangement scheme is that the collection devices extending from both sides of the main beam are used to measure the incoming wind field and the tail vortex behind the main beam, and the collection devices on the bridge deck and the bottom of the beam are used to measure the attached vortices above and below the main beam.

7. The bridge vortex vibration early warning system based on eddy current field monitoring according to claim 1 is characterized by: The vorticity calculation and prediction subsystem includes a vorticity calculation module and a vorticity prediction module.

8. The bridge vortex vibration early warning system based on eddy current field monitoring according to claim 1 is characterized by: The eddy current field analysis and early warning subsystem includes an eddy current field analysis module and a vortex vibration early warning module.

9. A bridge vortex vibration early warning method based on eddy current field monitoring, characterized in that: The specific steps are as follows: S1, CFD simulation is performed on the flow field around the main beam to obtain the vortex distribution around the main beam when vortex vibration occurs. The measurement point positions of the sensors are optimized according to the vortex cloud map. The vortex field data collected by the wind direction and speed acquisition instrument are vector-decomposed into the transverse wind speed and vertical wind speed. S2, using the vorticity calculation and prediction subsystem to calculate the vorticity of the wind field data collected by the wind field collection subsystem, taking the vorticity value based on the curl as the standard, the curl calculation formula is as follows: In actual situations, Δv is used instead of Δx instead Δy instead get In this system: Where ω(x, y) is the vortex curl at the wind speed and direction sensor, v x (x, y) and v y (x, y) are the lateral wind speed and vertical wind speed measured by the wind speed and direction sensor, v x (x, y+D) is the lateral wind speed measured by the unidirectional wind speed sensor at a vertical distance D from the wind speed and direction sensor, v y (x+D, y) is the vertical wind speed measured by the unidirectional wind speed sensor at a horizontal distance D from the wind speed and direction sensor. The positive or negative value of D is determined by the sensor layout position; The vorticity prediction module uses historical measured data as training samples and trains the prediction subsystem based on the LSTM method. The prediction subsystem uses real-time vorticity data to make predictions and obtain the vorticity values ​​and change trends of the measuring points in the future. S3, the eddy current field analysis and warning subsystem performs frequency domain analysis on the vorticity of each measuring point to obtain the vorticity of each point, the frequency of vorticity change, the phase difference between B-1 (B'-1) and B-2 (B'-2), C-1 (C'-1) and C-2 (C'-2). When the eddy current field analysis module results show a certain data, a vortex vibration warning is issued. The data and warning are as follows: (1) The vorticity value of A-1 (A'-1) or A-2 (A'-2) is large, and the frequency is close to the vertical bending frequency of the main beam, and a vertical bending vortex vibration warning is issued; (2) The vorticity value of A-1 (A'-1) or A-2 (A'-2) is large, and the frequency is close to the torsional frequency of the main beam, and a torsional vortex vibration warning is issued; (3) The phase difference between B-1 (B'-1) and B-2 (B'-2), C-1 (C'-1) and C-2 (C'-2) is about π / 2, and the frequency of change is close to the torsional frequency of the main beam, which issues a torsional vortex vibration warning; (4) For bridges with complex structures, it is necessary to analyze the overall vortex distribution status in combination with the data from all measurement points on the entire bridge.

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