A data acquisition and analysis method, system and device for a large-span steel tube concrete main arch

Abstract

The present invention relates to the field of engineering data processing technology, and more specifically, to a data collection and analysis method, system, and device for a large-span steel tube concrete main arch. The method provided by the present invention primarily involves acquiring point cloud data of the topography of the main arch, establishing a three-dimensional point cloud model from the point cloud data, calculating the shadow area of ​​the main arch during the acquisition period based on the three-dimensional point cloud model, acquiring real-time meteorological data of the main arch at different time periods at several observation points, determining the heat flux density of the main arch surface units based on the real-time meteorological data and the Dilger model, acquiring the initial temperature of the main arch, and determining and outputting the temperature stress of the main arch cross section based on the temperature distribution and the initial temperature of the main arch. Through the above method, the acquired data is further analyzed to provide feedback on the bridge's temperature distribution and temperature stress results, ensuring a comprehensive understanding and assessment of the temperature impact of the structure during actual operation and providing detailed data support for structural safety analysis.

Description

Technical Field

[0001] The present invention relates to the technical field of engineering data processing, and in particular to a method, system and device for collecting and analyzing data of a large-span steel tube concrete main arch. Background Art

[0002] With the rapid development of bridge construction in my country, the requirements for construction control and health monitoring of long-span steel tube concrete arch bridge structures during the construction phase and operation phase are becoming increasingly complex, systematic, and sophisticated. Construction control, as a crucial component of bridge construction, not only requires determining construction methods and process conditions based on structural analysis and on-site measurements, but also requires setting appropriate construction parameters to ensure that the bridge remains safe and stable throughout the construction period. During the operation phase, health monitoring provides real-time information on the bridge's health under the combined effects of various loads.

[0003] Meteorological data such as solar radiation, wind speed, and temperature are crucial factors influencing construction control parameters and operational health. Accurate structural health monitoring can only be ensured through accurate, real-time measurement of these meteorological parameters. However, current data collection often lacks detailed analysis, leaving room for improvement in determining structural safety.

[0004] Furthermore, the current measurement method involves installing meteorological stations near the bridge site or at different locations across the bridge to obtain meteorological parameter data. However, these stations are fixed. For long-span concrete-filled steel tube arch bridges, as the span and height increase, meteorological parameters at different locations on the bridge may vary. The increased number of fixed meteorological stations introduces a series of challenges, including high data collection costs, difficult installation, and difficulty in data transmission. Summary of the Invention

[0005] The purpose of the present invention is to provide a data collection and analysis method, system and device for a long-span steel tube concrete main arch to solve the above-mentioned problems in the prior art.

[0006] The embodiments of the present invention are achieved through the following technical solutions:

[0007] In a first aspect, the present invention provides a method for collecting and analyzing data of a long-span concrete-filled steel tube main arch, comprising:

[0008] Obtain point cloud data of the topography where the main arch is located, build a 3D point cloud model based on the point cloud data, and calculate the shadow area of ​​the main arch during the acquisition period based on the 3D point cloud model;

[0009] Based on the shadow area, the non-shadow area is obtained, and the real-time meteorological data of the main arch at different time periods at several observation points are obtained. Based on the real-time meteorological data and the Dilger model, the heat flux density of the main arch surface unit is obtained;

[0010] The temperature distribution on the main arch surface is obtained through the heat flux density, the initial temperature of the main arch is obtained, and the temperature stress of the main arch section is obtained and output through the temperature distribution and the initial temperature of the main arch.

[0011] Preferably, the step of establishing a three-dimensional point cloud model using point cloud data includes:

[0012] Determine the scope of the target area and set the control points for collecting point cloud data. Determine the layout parameters of the collection base station and set the flight path of the first UAV. Use the UAV to collect image data at the location of the collection base station.

[0013] Set the heading overlap rate and lateral overlap rate, and set the flight altitude limit function of the drone through the heading overlap rate;

[0014] The main arch is located at a location where three-dimensional modeling is performed on the spot to obtain a three-dimensional model of the main arch, the collected image data is obtained, and the coordinates of the image points in the overlapping area of ​​the image data and the control points are used to synthesize a three-dimensional point cloud model with real coordinate information.

[0015] Preferably, the function for setting the flight altitude limit of the drone includes:

[0016]

[0017] Where H is the flight altitude of the UAV, Δx is the terrain height difference, and O is the heading overlap rate.

[0018] Preferably, obtaining the shadow distribution area of ​​the main arch during the acquisition period includes:

[0019] Establishing a main arch three-dimensional shell element model based on a finite element unit, and importing the main arch three-dimensional model into the main arch three-dimensional shell element model;

[0020] Discretize the surface of the main arch three-dimensional shell element model into triangular mesh surface elements, and establish the element set and node coordinate set of different components;

[0021] The solar altitude and azimuth at a certain moment are obtained, and the solar direction vector at that moment is obtained through the altitude and azimuth. The solar direction vector is used to determine whether any surface unit of the main arch is blocked by the terrain and the shadow area of ​​the main arch is obtained.

[0022] Preferably, judging whether any surface unit of the main arch is blocked by the terrain by using the sun direction vector includes:

[0023] Get the three unit node coordinates of the surface unit scattered into a triangular mesh through the three unit node coordinates;

[0024] The center point coordinates are projected along the sun direction vector to determine whether a projection point is formed at any position of the main arch three-dimensional shell element model. If a projection point is formed, the surface element is determined to be a shadow area at this moment. If no projection point is formed, the surface element is determined to be a non-shadow area at this moment.

[0025] Preferably, the determining that the surface unit is a shadow area at this moment includes determining that the surface unit is a self-shadow area blocked by its own back surface, or an other-shadow area blocked by other components, including:

[0026] Calculate the element normal vector of the surface element through the three element node coordinates;

[0027] Calculate whether the dot product of the sun direction vector and the element normal vector is less than or equal to 0. If it is less than or equal to 0, the surface element is divided into a self-shadow area. If it is greater than 0, the center point of the surface element is obtained through the element node coordinates.

[0028] A ray is established through the center point and the sun direction vector. The intersection of the ray and any plane is used as the starting point. Three vectors are constructed with three unit nodes as the end points. After cross-producting the three vectors, it is determined whether the directions are the same. If they are the same, the surface unit is judged to be a shadow area. If they are not the same, it is judged to be a non-shadow area.

[0029] Preferably, obtaining the real-time meteorological data of the main arch at different time periods includes setting a second UAV flight route, and the second UAV flight route includes:

[0030] determining an arch rib type of the bridge, wherein the arch rib type includes a single arch rib and multiple arch ribs;

[0031] When the arch rib type is determined to be a single arch rib, a signal is sent to cause the UAV to fly along the outer side of the arch rib parallel to the arch rib axis;

[0032] When the arch rib type is determined to be multiple arch ribs, a signal is sent to cause the drone to fly in a zigzag pattern along the outer side of the arch rib parallel to the arch rib axis, alternating up and down.

[0033] Preferably, obtaining the heat flux density of the main arch surface unit includes:

[0034] The theoretical heat flux density is obtained through the Dilger model and the angle of the sun's rays;

[0035] Obtain the direct solar radiation value from the real-time meteorological data, define the error function, and find the adjustment coefficient that minimizes the error function E through the least squares method;

[0036] The theoretical heat flux density at each observation point is scaled according to the adjustment coefficient to obtain the corrected heat flux density.

[0037] In the second aspect, a data acquisition and analysis system for a large-span concrete-filled steel tube main arch includes:

[0038] a three-dimensional model building module configured to obtain point cloud data of the topography where the main arch is located, and to build a three-dimensional point cloud model based on the point cloud data;

[0039] a shadow recognition module configured to calculate the shadow area of ​​the main arch during the acquisition period based on the three-dimensional point cloud model;

[0040] The solar radiation model calculation module is configured to obtain the non-shadow area based on the shadow area, obtain the real-time meteorological data of the main arch at different time periods at several observation points, and obtain the heat flux density of the main arch surface unit based on the real-time meteorological data and the Dilger model;

[0041] The temperature field analysis module is configured to obtain the temperature distribution of the main arch surface through the heat flux density, obtain the initial temperature of the main arch, and obtain and output the temperature stress of the main arch section through the temperature distribution and the initial temperature of the main arch;

[0042] A main control device is connected to the three-dimensional model building module, shadow recognition module, solar radiation model calculation module and temperature field analysis module, and is used to execute the above-mentioned large-span steel tube concrete main arch data collection and analysis method.

[0043] In a third aspect, a data acquisition and analysis device for a large-span concrete-filled steel tube main arch includes a drone;

[0044] The UAV is provided with a meteorological data acquisition device and a processing unit, and the processing unit is connected to the meteorological data acquisition device and the UAV, and is used to execute the above-mentioned method for collecting and analyzing data of a large-span steel tube concrete main arch;

[0045] The meteorological data collection device includes a wind speed meter, a wind direction meter, a solar radiation sensor, and a temperature sensor.

[0046] The technical solutions of the embodiments of the present invention have at least the following advantages and beneficial effects:

[0047] The method provided by the present invention primarily involves acquiring point cloud data of the topography of the main arch, building a three-dimensional point cloud model from the point cloud data, calculating the main arch's shadow area during the acquisition period based on the three-dimensional point cloud model, acquiring real-time meteorological data of the main arch at different observation points during different periods, and determining the heat flux density of the main arch surface units based on the real-time meteorological data and the Dilger model. The temperature distribution of the main arch surface is determined from the heat flux density, the initial temperature of the main arch is obtained, and the temperature stress of the main arch cross section is determined and output based on the temperature distribution and the initial temperature of the main arch. Through this method, the acquired data is further analyzed, providing feedback on the bridge's temperature distribution and temperature stress results, ensuring a comprehensive understanding and assessment of the temperature impact of the structure during actual operation and providing detailed data support for structural safety analysis.

[0048] Secondly, the present invention also uses drones as carriers to collect, transmit and analyze various data, so that data from multiple points of the main arch can be collected through a set of equipment, which reduces costs and solves the problem of difficult installation of current fixed weather stations. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0050] Figure 1 The structural temperature field calculation process of the present invention;

[0051] Figure 2 Schematic diagram of the point cloud dataset of the present invention.

[0052] Figure 3 Schematic diagram of the imaging range of the present invention;

[0053] Figure 4 It is a schematic diagram of image overlap of the present invention;

[0054] Figure 5 It is a schematic diagram of the overlapping area of ​​the present invention;

[0055] Figure 6 It is a schematic diagram of the projection points of the present invention;

[0056] Figure 7 A schematic diagram of a triangular mesh and three nodes of the present invention;

[0057] Figure 8 Schematic diagram of the self-shadow and other-shadow judgment process of the present invention;

[0058] Figure 9 A schematic diagram of the flight path of a single-arch UAV according to the present invention;

[0059] Figure 10 A schematic diagram of the flight path of the multi-arch UAV of the present invention;

[0060] Figure 11 This is a schematic structural diagram of the data collection and analysis device of the present invention;

[0061] Icons: 1- wind speed meter, 2- wind direction meter, 3- solar radiation sensor, 4- temperature sensor, 5- drone, 6- camera. DETAILED DESCRIPTION

[0062] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0063] The division of modules in the application is a logical division. In actual application, there may be other division methods. For example, multiple modules can be combined or integrated into another system, or some features can be ignored or not executed.

[0064] Independently described modules or submodules may or may not be physically separate; they may be implemented in software or hardware. Some modules or submodules may be implemented in software, with the processor invoking the software to implement the functionality of these modules or submodules, while other modules or submodules may be implemented in hardware, such as hardware circuits. Furthermore, some or all of the modules may be selected based on actual needs to achieve the objectives of the present application.

[0065] Please refer to Figure 1-2 As shown, the present invention provides a data collection and analysis method for a long-span steel tube concrete main arch, comprising:

[0066] S101: acquiring point cloud data of the topography where the main arch is located, establishing a three-dimensional point cloud model based on the point cloud data, and calculating the shadow area of ​​the main arch during the acquisition period based on the three-dimensional point cloud model;

[0067] Using a high-definition camera mounted on a drone, based on the altitude of the coordinate system origin, a grid was arranged within 500m beyond the bridge outline in the bridge site plan to obtain a large number of coordinate point cloud datasets of the terrain and landforms near the bridge site, which were used to generate a three-dimensional terrain model.

[0068] S102: Based on the shadow area, a non-shadow area is obtained, real-time meteorological data of the main arch at several observation points at different time periods are obtained, and heat flux density of the main arch surface unit is obtained based on the real-time meteorological data and the Dilger model;

[0069] A drone takeoff and landing platform was set up near the arch foot of the arch bridge. Equipped with a high-definition camera and a portable meteorological instrument, the drone flew to a designated location directly above the centerline of the bridge span, unobstructed by other bridge components to ensure full sunlight exposure. It hovered at this location and collected meteorological data, including instantaneous horizontal direct irradiance, instantaneous horizontal diffuse irradiance, and air temperature. This location was used as the origin of the coordinate system, and the altitude of that point was recorded.

[0070] S103: Obtain the temperature distribution of the main arch surface through the heat flux density, obtain the initial temperature of the main arch, and obtain and output the temperature stress of the main arch cross section through the temperature distribution and the initial temperature of the main arch.

[0071] Specifically, the location and number of sections for which the temperature field needs to be calculated are determined. Then, the unit sets and coordinate information for each section at each location are automatically identified from the 3D bridge model. Using this information, a 2D model is automatically generated, and a 2D heat conduction differential equation is established, assuming a constant material thermal conductivity and no internal heat sources.

[0072]

[0073] Where t is temperature, τ is time, a is thermal diffusivity, and x, y, and z are spatial coordinates in a rectangular coordinate system.

[0074] Furthermore, the collected air temperature is applied to the edge of the two-dimensional model as the first-type boundary condition of the heat conduction problem.

[0075] Furthermore, the wind speed data collected at different cross sections are combined with the convective heat transfer coefficient and the temperature of the surrounding fluid and applied to the edge of the two-dimensional model as the third type of boundary condition for the heat conduction problem.

[0076] Furthermore, the heat flux density of the surface unit is used as the second type of boundary condition for the heat conduction problem and applied to the units corresponding to the edge in the two-dimensional model.

[0077] In this way, the temperature distribution of the bridge cross section can be calculated, and combined with the initial temperature of the bridge when it is completed, the temperature stress of the bridge cross section can be calculated using finite element software.

[0078] The method provided by the present invention primarily involves acquiring point cloud data of the topography of the main arch, building a three-dimensional point cloud model from the point cloud data, calculating the main arch's shadow area during the acquisition period based on the three-dimensional point cloud model, acquiring real-time meteorological data of the main arch at different observation points during different periods, and determining the heat flux density of the main arch surface units based on the real-time meteorological data and the Dilger model. The temperature distribution of the main arch surface is determined from the heat flux density, the initial temperature of the main arch is obtained, and the temperature stress of the main arch cross section is determined and output based on the temperature distribution and the initial temperature of the main arch. Through this method, the acquired data is further analyzed, providing feedback on the bridge's temperature distribution and temperature stress results, ensuring a comprehensive understanding and assessment of the temperature impact of the structure during actual operation and providing detailed data support for structural safety analysis.

[0079] An exemplary embodiment of the present invention is as follows Figure 3-5 As shown, establishing a 3D point cloud model through point cloud data includes:

[0080] S201: Determine the scope of the target area, set control points for collecting point cloud data, determine the layout parameters of the collection base station and set the flight path of the first UAV, and use the UAV to collect image data at the location of the collection base station;

[0081] The control points need to have clear information such as their latitude, longitude, and altitude, and the base station layout parameters can include shooting distance, observation area length, base station spacing, etc. The resolution of the image data can be obtained by combining these parameters with the parameters of the shooting camera.

[0082]

[0083] Where H is the shooting distance, p s is the pixel size, f is the focal length of the camera, and Y is the resolution.

[0084] After obtaining the resolution, the parameters can be adjusted according to the ground resolution requirements so that the resolution meets the detection requirements.

[0085] S202: Setting the heading overlap rate and the lateral overlap rate, and setting the flight altitude limit function of the UAV according to the heading overlap rate;

[0086] When terrain has elevation differences, the overlapping shadow area gradually decreases. The key to point cloud modeling is to measure the coordinates of points in the overlapping image area, combine the coordinates of control points, and the collective relationship between the image and the captured terrain, to calculate the coordinates of each encrypted point in the image. Therefore, the reduction of overlapping shadows will lead to reduced modeling accuracy. To meet the modeling accuracy requirements, the heading overlap ratio in this embodiment is set to 60%-80%, and the lateral overlap ratio is set to 15%-80%.

[0087] Specifically, the function for setting the flight altitude limit of the drone includes:

[0088]

[0089] Where H is the flight altitude of the UAV, Δx is the terrain height difference, and O is the heading overlap rate.

[0090] S203: Performing on-site three-dimensional modeling of the main arch location to obtain a three-dimensional model of the main arch, acquiring the collected image data, and synthesizing a three-dimensional point cloud model with real coordinate information through the coordinates of image points in overlapping areas of the image data and control points.

[0091] After obtaining relatively ideal image data, the image data is spliced ​​and integrated into a three-dimensional point cloud model with real coordinate information by combining the image point coordinates in the overlapping area of ​​the image data with the pre-set control point information and using the focal length and control point information of the captured image.

[0092] The established model is edited, mainly to eliminate or crop points irrelevant to modeling, and then the 3D model is smoothed and denoised, and finally a solid 3D point cloud model of the target area is obtained.

[0093] An exemplary embodiment of the present invention is as follows Figure 6-8 As shown, the shadow distribution area of ​​the main arch during the acquisition period includes:

[0094] S301: establishing a main arch three-dimensional shell element model based on a finite element unit, and importing the main arch three-dimensional model into the main arch three-dimensional shell element model;

[0095] A 3D shell element model of the main arch was established using the finite element method. The 3D model of the main arch was then imported and its surface discretized into a triangular mesh. The element set Set_elements and the node coordinate set Set_nodes for the different components were established. It should be noted that since the 3D topographic model is not used in the calculation of the bridge temperature field, the topographic mesh size far exceeds the mesh size on the bridge component surface.

[0096] S302: discretize the surface of the main arch three-dimensional shell element model into surface elements of a triangular mesh, and establish element sets and node coordinate sets of different components;

[0097] S303: Obtain the solar altitude angle and azimuth at a certain moment, obtain the solar direction vector at that moment through the altitude angle and azimuth, determine whether any surface unit of the main arch is blocked by the terrain through the solar direction vector, and obtain the shadow area of ​​the main arch.

[0098] Specifically, judging whether any surface unit of the main arch is blocked by the terrain by using the sun direction vector includes:

[0099] Get the three unit node coordinates of the surface unit scattered into a triangular mesh through the three unit node coordinates;

[0100] The center point coordinates are projected along the sun direction vector to determine whether a projection point is formed at any position of the main arch three-dimensional shell element model. If a projection point is formed, the surface element is determined to be a shadow area at this moment. If no projection point is formed, the surface element is determined to be a non-shadow area at this moment.

[0101] Specifically, determining that the surface unit is a shadow area at this moment includes determining that the surface unit is a self-shadow area blocked by its own back surface, or an other-shadow area blocked by other components, including:

[0102] Calculate the element normal vector of the surface element through the three element node coordinates;

[0103] Calculate whether the dot product of the sun direction vector and the element normal vector is less than or equal to 0. If it is less than or equal to 0, the surface element is divided into a self-shadow area. If it is greater than 0, the center point of the surface element is obtained through the element node coordinates.

[0104] A ray is established through the center point and the sun direction vector. The intersection of the ray and any plane is used as the starting point. Three vectors l1, l2, and l3 are constructed with three unit nodes as the end points. The cosine values ​​of the angles between the vectors are calculated. The angles of the three vectors with three unit nodes as the end points are α1, α2, and α3.

[0105] cosα1=dot(l1,l2) / (norm(l1)*norm(l2))

[0106] cosα2=dot(l2,l3) / (norm(l2)*norm(l3))

[0107] cosα3=dot(l3,l1) / (norm(l3)*norm(l1))

[0108] If the cross product directions of these vectors are the same, that is, cosα11=cosα2=cosα3=1, then the surface unit is judged as a shadow area; if they are different, then it is judged as a non-shadow area.

[0109] In this example, you can also make a judgment by following the steps below:

[0110] If the projection point is within the spatial plane formed by a certain topographic unit, it means that the sunlight shining on the surface of the bridge unit is blocked by the topographic unit.

[0111] The obstructed bridge surface units are added to the set Set_bri_Mo1. Next, the set Set_bri of bridge surface units is subtracted from the set Set_bri_Mo1 of bridge surface units obstructed by topography, thereby obtaining the set Set_bri_part of bridge surface units not obstructed by topography.

[0112] Next, determine whether the bridge surface unit set Set_bri_part is obscured by its own back face by comparing the angle between the unit surface's outer normal vector and the sun's direction vector. If the angle is greater than or equal to 90°, it indicates that the light is incident from the opposite direction and the unit surface is obscured by its own back face. These units are added to the self-shadowing set Set_bri_So.

[0113] Furthermore, the subtraction of all unit sets Set_bri_part contained in the bridge and the self-shadow set Set_bri_So is performed, thereby obtaining the bridge surface unit set Set_bri_part2 that is not blocked by its own rods.

[0114] Furthermore, to determine whether the unit surface in the Set_bri_part2 set is blocked by other bridge components, you can follow the steps below:

[0115] Use the three node coordinates of the surface unit in the Set_bri_part2 set to calculate the center point coordinates of the bridge surface unit coord_cen_bri2_i;

[0116] Project the coordinates of the center point along the sun direction vector, and the projection point should fall on the space plane formed by the remaining units in the Set_bri_part2 set except this unit.

[0117] If the projection point is within the spatial plane formed by one of the remaining units, it means that the sunlight shining on the surface of the bridge unit is blocked by other components.

[0118] The blocked bridge surface units are added to the set Set_bri_Mo2. Next, the set Set_bri_part2 of the bridge surface units is subtracted from the set Set_bri_Mo2 to obtain the bridge surface illumination unit set Set_bri_No.

[0119] Through the above steps, the bridge surface units that are blocked by terrain, blocked by their own back, blocked by other components, and under light are divided into different sets.

[0120] An exemplary embodiment of the present invention, referring to Figure 9-10As shown, obtaining real-time meteorological data of the main arch at different time periods includes setting a second UAV flight route, and the second UAV flight route includes:

[0121] S401: Determine the arch rib type of the bridge, where the arch rib type includes a single arch rib and multiple arch ribs;

[0122] S402: When the arch rib type is determined to be a single arch rib, a signal is sent to cause the UAV to fly along the outer side of the arch rib parallel to the arch rib axis;

[0123] Specifically, the drone's flight path is first established. Based on the arch rib axis's position in the coordinate system, a main flight path is set along the arch rib's outer side, parallel to the rib axis. The number of stop points Po,i is set along the main flight path based on the bridge's span and the precise requirements for temperature field calculations.

[0124] After completing a self-check, the drone, equipped with a high-definition camera and a portable meteorological instrument, took off from one arch foot and flew along the designated main flight path to point Po,1. After confirming the coordinates of Po,1, it stopped to collect horizontal solar radiation, air temperature, wind speed, and other relevant data samples, while also recording the collection time and altitude. The drone then continued to the next stop, Po,2, until it reached the other arch foot. The measurement plan included round trip flights, with two stops and measurements at each stop.

[0125] S403: When the arch rib type is determined to be multiple arch ribs, a signal is sent to make the UAV fly in a zigzag pattern along the outer side of the arch rib parallel to the arch rib axis in an alternating manner.

[0126] Concrete-filled steel tube truss arch bridges typically have two vertical arch rib axes due to their numerous members. Dwelling points are arranged on each of these axes, and the drone's flight path is set in a Z-shaped pattern. The flight begins at the arch foot on one side, first arriving at the dwelling point Po,d1 on the lower chord arch rib, where it hovers and collects meteorological data. The drone then moves vertically to the dwelling point Po,u1 on the corresponding upper chord arch rib, where it hovers and collects meteorological data again. The drone then pitches past this point, proceeding to the next dwelling point Po,d2 on the lower chord arch rib, until it reaches the arch foot on the other side. The measurement plan includes round trip flights, with two stops and meteorological data collection at each dwelling point.

[0127] In addition, for key cross-sectional locations other than the arch ribs, secondary flight routes are set, and the UAV reaches the stop point through hovering, vertical, pitch, roll, and yaw movements to complete meteorological data collection.

[0128] After the drone flight data collection is completed, it returns to the drone take-off and landing platform set up near the arch foot and transmits the data back for analysis.

[0129] Taking into account the time-varying characteristics of solar radiation, air temperature and wind speed, the flight and sampling frequencies are reasonably set according to the meteorological change rate near the bridge site.

[0130] In an exemplary embodiment of the present invention, obtaining the heat flux density of the main arch surface unit includes:

[0131] S501: Obtain theoretical heat flux density using the Dilger model and the angle of sunlight;

[0132] Direct solar radiation refers to the radiant energy from sunlight that directly reaches the ground through the atmosphere. The intensity of this radiation depends on factors such as the sun's altitude, atmospheric transparency, cloud cover, and the ground's altitude. Diffuse solar radiation refers to the solar radiation that, when passing through the atmosphere, is scattered by gases, dust, and aerosols in the atmosphere, ultimately reaching the ground from all directions in the sky. The intensity of this radiation is primarily determined by factors such as the angle of incidence of the solar radiation and atmospheric conditions. In illuminated areas, the total solar radiation received by bridge surface units includes direct solar radiation, diffuse radiation, and ground reflection. In shadowed areas, the total solar radiation received by bridge surface units includes only diffuse radiation and ground reflection. The Dilger solar radiation model is used to calculate the direct solar radiation received by bridge surfaces.

[0133] S502: Obtain the direct solar radiation value in the real-time meteorological data, define an error function, and find an adjustment coefficient that minimizes the error function E through the least squares method;

[0134] S503: Scale the theoretical heat flux density of each observation point according to the adjustment coefficient to obtain a corrected heat flux density.

[0135] According to the Dilger model, the intensity of direct solar radiation is related to the atmospheric transparency coefficient (P) on a clear day, the atmospheric absorption constant (tu), and the relative atmospheric pressure at the bridge site. Using drone-derived meteorological data at the bridge site at different time periods, the atmospheric absorption constant (tu) can be inferred and used to further refine the empirical parameters in the Dilger model.

[0136] Next, the heat flux density of the bridge surface element Set_bri is calculated based on the Dilger model and the angular relationship between the components and the sun's rays. This heat flux density is the theoretical value qcal,i obtained by the model under clear weather conditions, but it does not take into account the effect of cloud thickness on direct solar radiation. An adjustment factor k is introduced to account for the effect of cloud thickness on direct solar radiation.

[0137] In conjunction with the flight control system's third step, the drone's stops along the flight path collect horizontal direct solar radiation (qtest,i) at different bridge cross-section locations. The data is compared with the theoretical value (qcal,i) calculated by the model at that point. An error function E is defined as the sum of the squares of the errors at all measurement points. The least squares method is used to find the parameter that minimizes the error function E, i.e., the overall adjustment factor k. Assuming the adjustment factor is the same for all measurement points, the overall adjustment factor k is determined by minimizing the error function E. The calculated theoretical heat flux density of each bridge surface unit is then adjusted by scaling the calculated value at each measurement point by k.

[0138] Specifically:

[0139]

[0140] k=(X T X) -1 X T Y

[0141] Where f(x) is the theoretical value of the model at each point, E is the defined error function, X is the data matrix observed by the UAV, Y is the theoretical value vector corresponding to f(x), and k is the coefficient vector to be obtained.

[0142] Since the present invention adopts many empirical formulas or coefficients for calculation, it is necessary to compare and verify the data of each parameter adopted. The main function of the data verification module is to compare whether the parameter values ​​adopted in the clear sky model are accurate.

[0143] Specifically, the heat flux density data is acquired and compared with the total solar radiation on the horizontal plane to verify whether the parameter values ​​used in the clear sky model are accurate. For the heat flux density calculation value, this data verification module needs to set the system threshold β, and substitute the heat flux density calculation value obtained by the drone collection data and the shadow recognition module into the following formula to calculate the relative error.

[0144]

[0145] Where α is the relative error, q2 is the calculated value of heat flux, and q1 is the total solar radiation on the horizontal plane.

[0146] If the error is within the system threshold range, the calculation and analysis module can be entered. If the error is outside the system threshold range, the parameter values ​​used in the aforementioned clear sky model calculation need to be corrected until the relative error between the calculated value of the total solar radiation on the horizontal plane and the data value collected by the solar radiation sensor is within the threshold β range.

[0147] In the second aspect, a data acquisition and analysis system for a large-span concrete-filled steel tube main arch includes:

[0148] a three-dimensional model building module configured to obtain point cloud data of the topography where the main arch is located, and to build a three-dimensional point cloud model based on the point cloud data;

[0149] a shadow recognition module configured to calculate the shadow area of ​​the main arch during the acquisition period based on the three-dimensional point cloud model;

[0150] The solar radiation model calculation module is configured to obtain the non-shadow area based on the shadow area, obtain the real-time meteorological data of the main arch at different time periods at several observation points, and obtain the heat flux density of the main arch surface unit based on the real-time meteorological data and the Dilger model;

[0151] The temperature field analysis module is configured to obtain the temperature distribution of the main arch surface through the heat flux density, obtain the initial temperature of the main arch, and obtain and output the temperature stress of the main arch section through the temperature distribution and the initial temperature of the main arch;

[0152] A main control device is connected to the three-dimensional model building module, shadow recognition module, solar radiation model calculation module and temperature field analysis module, and is used to execute the above-mentioned large-span steel tube concrete main arch data collection and analysis method.

[0153] In a third aspect, a data acquisition and analysis device for a large-span concrete-filled steel tube main arch includes a drone;

[0154] The UAV is provided with a meteorological data acquisition device and a processing unit, and the processing unit is connected to the meteorological data acquisition device and the UAV 5, and is used for the above-mentioned method for collecting and analyzing data of a large-span steel tube concrete main arch;

[0155] The meteorological data collection device includes a wind speed meter 1 , a wind direction meter 2 , a solar radiation sensor 3 and a temperature sensor 4 .

[0156] The anemometer 1, wind direction meter 2, solar radiation sensor 3 and temperature sensor 4 are all fixed on the meteorological parameter collection mechanism bracket, which is made of light-weight steel such as carbon steel. The structure can be hollowed out to further reduce the weight and facilitate the movement of the drone 5.

[0157] The UAV includes a power device, a bracket fixing bolt is set on the top of the UAV for fixing the meteorological parameter collection mechanism, a processing unit is set at the rear of the UAV, and a high-definition camera 6 is set in front of the UAV to provide a convenient field of view for the UAV operator. The camera can store video footage, and a meteorological parameter collection mechanism power supply is set under the UAV to supply power to the sensors arranged on the meteorological parameter collection mechanism.

[0158] The meteorological collection mechanism bracket is a device that connects the drone to the meteorological sensor. The structure is composed of a T-shaped bracket, and 4 holes are evenly arranged at the top for fixing various meteorological parameter sensors.

[0159] In addition, the functional units in the various embodiments of the present invention may be integrated into a single processing unit, each unit may exist physically separately, or two or more units may be integrated into a single unit. The aforementioned integrated units may be implemented in the form of hardware or software functional units.

[0160] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. The computer software product is stored in a storage medium and includes a number of instructions for causing a computer device (which can be a personal computer, server, or network device, etc.) to perform all or part of the steps of the various embodiments of the present invention. The aforementioned storage medium includes: USB flash drives, mobile hard drives, read-only memories (ROMs), random access memories (RAMs), magnetic disks, optical disks, and other media that can store program code.

[0161] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A data collection and analysis method for a long-span steel tube concrete main arch, characterized in that: include: Obtain point cloud data of the topography where the main arch is located, build a 3D point cloud model based on the point cloud data, and calculate the shadow area of ​​the main arch during the acquisition period based on the 3D point cloud model; Based on the shadow area, the non-shadow area is obtained, and the real-time meteorological data of the main arch at different time periods at several observation points are obtained. Based on the real-time meteorological data and the Dilger model, the heat flux density of the main arch surface unit is obtained; The temperature distribution on the main arch surface is obtained through the heat flux density, the initial temperature of the main arch is obtained, and the temperature stress of the main arch section is obtained and output through the temperature distribution and the initial temperature of the main arch; The shadow distribution area of ​​the main arch obtained during the acquisition period includes: Establish a three-dimensional shell element model of the main arch based on the finite element unit, and import the three-dimensional model of the main arch into the three-dimensional shell element model of the main arch; Discretize the surface of the main arch three-dimensional shell element model into triangular mesh surface elements, and establish the element set and node coordinate set of different components; Obtain the solar altitude and azimuth at a certain moment, and use the altitude and azimuth to obtain the solar direction vector at that moment. Use the solar direction vector to determine whether any surface unit of the main arch is blocked by the terrain and obtain the shadow area of ​​the main arch. The step of judging whether any surface unit of the main arch is blocked by the terrain by using the sun direction vector includes: Get the three unit node coordinates of the surface unit scattered into a triangular mesh through the three unit node coordinates; Project the center point coordinates along the sun direction vector to determine whether a projection point is formed at any position of the main arch three-dimensional shell element model. If a projection point is formed, the surface element is determined to be a shadow area at this moment; if no projection point is formed, the surface element is determined to be a non-shadow area at this moment; The determining that the surface unit is a shadow area at this moment includes determining that the surface unit is a self-shadow area blocked by its own back surface, or an other-shadow area blocked by other components, including: Calculate the element normal vector of the surface element through the three element node coordinates; Calculate whether the dot product of the sun direction vector and the element normal vector is less than or equal to 0. If it is less than or equal to 0, the surface element is divided into a self-shadow area. If it is greater than 0, the center point of the surface element is obtained through the element node coordinates. A ray is established through the center point and the sun direction vector. The intersection of the ray and any plane is used as the starting point. Three vectors are constructed with three unit nodes as the end points. After cross-producting the three vectors, it is determined whether the directions are the same. If they are the same, the surface unit is judged to be a shadow area. If they are not the same, it is judged to be a non-shadow area.

2. The data collection and analysis method for a large-span steel tube concrete main arch according to claim 1 is characterized in that: The establishing of a three-dimensional point cloud model by using point cloud data includes: Determine the scope of the target area and set the control points for collecting point cloud data. Determine the layout parameters of the collection base station and set the flight path of the first UAV. Use the UAV to collect image data at the location of the collection base station. Set the heading overlap rate and lateral overlap rate, and set the flight altitude limit function of the drone through the heading overlap rate; The main arch is located at a location where three-dimensional modeling is performed on the spot to obtain a three-dimensional model of the main arch, the collected image data is obtained, and the coordinates of the image points in the overlapping area of ​​the image data and the control points are used to synthesize a three-dimensional point cloud model with real coordinate information.

3. The data collection and analysis method for a large-span steel tube concrete main arch according to claim 2 is characterized in that: The function for setting the flight altitude limit of the drone includes: Where H is the flight altitude of the UAV, is the terrain height difference, Heading overlap ratio.

4. The data collection and analysis method for a large-span steel tube concrete main arch according to claim 3 is characterized in that: The acquiring of real-time meteorological data of the main arch at different time periods includes setting a second UAV flight route, wherein the second UAV flight route includes: determining an arch rib type of the bridge, wherein the arch rib type includes a single arch rib and multiple arch ribs; When the arch rib type is determined to be a single arch rib, a signal is sent to cause the UAV to fly along the outer side of the arch rib parallel to the arch rib axis; When the arch rib type is determined to be multiple arch ribs, a signal is sent to cause the drone to fly in a zigzag pattern along the outer side of the arch rib parallel to the arch rib axis, alternating up and down.

5. The data collection and analysis method for a large-span steel tube concrete main arch according to claim 4 is characterized in that: Obtaining the heat flux density of the main arch surface unit includes: The theoretical heat flux density is obtained through the Dilger model and the angle of the sun's rays; Obtain the direct solar radiation value from the real-time meteorological data, define the error function, and find the adjustment coefficient that minimizes the error function E through the least squares method; The theoretical heat flux density at each observation point is scaled according to the adjustment coefficient to obtain the corrected heat flux density.

6. A data acquisition and analysis system for a large-span steel tube concrete main arch, characterized in that: include: a three-dimensional model building module configured to obtain point cloud data of the topography where the main arch is located, and to build a three-dimensional point cloud model based on the point cloud data; a shadow recognition module configured to calculate the shadow area of ​​the main arch during the acquisition period based on the three-dimensional point cloud model; The solar radiation model calculation module is configured to obtain the non-shadow area based on the shadow area, obtain the real-time meteorological data of the main arch at different time periods at several observation points, and obtain the heat flux density of the main arch surface unit based on the real-time meteorological data and the Dilger model; The temperature field analysis module is configured to obtain the temperature distribution of the main arch surface through the heat flux density, obtain the initial temperature of the main arch, and obtain and output the temperature stress of the main arch section through the temperature distribution and the initial temperature of the main arch; A main control device, which is connected to the three-dimensional model establishment module, shadow recognition module, solar radiation model calculation module and temperature field analysis module, and is used to execute the large-span steel tube concrete main arch data acquisition and analysis method described in any one of claims 1 to 5.

7. A data acquisition and analysis device for a large-span steel tube concrete main arch, characterized in that: Including drones; The UAV is provided with a meteorological data acquisition device and a processing unit, and the processing unit is connected to the meteorological data acquisition device and the UAV, and is used to execute the data acquisition and analysis method for a large-span steel tube concrete main arch according to any one of claims 1 to 5; The meteorological data collection device includes a wind speed meter, a wind direction meter, a solar radiation sensor, and a temperature sensor.

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