Bridge modal parameter testing method and system

Abstract

The application discloses a bridge modal parameter testing method and system; the method comprises the following steps: determining a testing scheme according to the bridge structure of a bridge to be tested; generating the dynamic deflection time history curve of each measuring point of the bridge to be tested based on the testing scheme; determining the model input parameter time history curve of each measuring point according to the dynamic deflection time history curve of each measuring point; and outputting the modal parameter of the bridge to be tested according to the modal parameter testing model corresponding to the bridge to be tested and the model input parameter time history curve of each measuring point. In the application, the measuring parameters of each measuring point of the bridge to be tested are collected by a radar, and the speed / acceleration parameters of each measuring point are obtained based on the measuring parameters, so that the testing of the modal parameter of the bridge is realized, the flexibility of the equipment deployment of each measuring point of the bridge to be tested is improved, and the dependence on sensor equipment is relieved.

Description

Technical Field

[0001] This application relates to the field of bridge modal testing technology, specifically to a method and system for testing bridge modal parameters. Background Technology

[0002] With the development of economic construction, higher and higher demands are being placed on transportation; the ever-increasing traffic volume and the ever-increasing vehicle load capacity are testing the load-bearing capacity of bridges.

[0003] The main parameters representing the load-bearing capacity of a bridge are its mode shape, damping ratio, and natural frequency. The natural vibration characteristics of a bridge are mainly analyzed through bridge modal parameter testing to obtain parameters such as the mode shape, natural frequency, and damping ratio corresponding to the actual bridge structure.

[0004] Currently, bridge modal parameter testing technology determines the location of measuring points based on the type of bridge structure and the order of the bridge vibration modes. The vibration signals of the bridge structure are obtained by setting up wired equipment such as velocity or acceleration sensors at the measuring points. This method is highly dependent on sensor equipment and has high costs.

[0005] In other words, current methods for testing bridge modal parameters suffer from a high degree of dependence on sensor equipment. Summary of the Invention

[0006] The purpose of this invention is to alleviate the technical problem of the current bridge modal parameter testing methods being highly dependent on sensor equipment, and to provide a bridge modal parameter testing method and system.

[0007] The above-mentioned objective of the present invention is achieved through the following technical solution:

[0008] Firstly, this application provides a method for testing bridge modal parameters, the method comprising:

[0009] Based on the bridge structure of the bridge to be tested, a test plan is determined; the test plan includes the setting parameters of the test radar in the test system and the excitation method;

[0010] Based on the aforementioned test scheme, the dynamic deflection time history curves of each measuring point of the bridge under test are generated.

[0011] Based on the dynamic deflection time history curves of each measuring point, determine the model input parameter time history curves of each measuring point;

[0012] Based on the modal parameter test model corresponding to the bridge under test and the time history curves of the model input parameters at each measuring point, the modal parameters of the bridge under test are output.

[0013] This application employs the aforementioned technical solution to obtain the bridge structure of the bridge under test, formulate a testing plan, and use radar testing as the testing tool. The excitation method is determined appropriately based on the bridge structure. The testing radar collects measurement parameters from each measuring point and generates dynamic deflection time history curves for each measuring point of the bridge under test based on these parameters. A suitable dynamic deflection time history curve is selected as the model input parameter time history curve for the modal parameter test model corresponding to the bridge under test. Finally, after modal analysis, the modal parameters of the bridge under test are output. This solves the technical problem of the current bridge modal parameter testing methods' high dependence on sensor equipment.

[0014] Optionally, the step of determining the test plan based on the bridge structure of the bridge under test in the aforementioned method includes: obtaining the vibration order of the bridge under test; determining the excitation method based on the span parameters in the bridge structure; determining the position parameters and quantity parameters in the setting parameters based on the bridge structure and the vibration order; and outputting the test plan based on the excitation method, the position parameters, and the quantity parameters.

[0015] This application employs the aforementioned technical solution, selecting a suitable excitation method based on the span parameters of the bridge structure. The vibration order of the bridge under test is obtained, and the location and number of test radars are determined according to the bridge structure and vibration order. A test plan is then determined based on the excitation method and the location and number of test radars. Selecting a suitable excitation method based on the bridge's span amplifies the characteristics of the bridge under test, facilitating data collection from the measurement points by the test radars. The test radars are rationally deployed according to the bridge structure and vibration order to ensure that they can comprehensively collect the measurement parameters from each measurement point.

[0016] Optionally, the step of determining the excitation mode based on the span parameters in the bridge structure in the aforementioned method includes: when the span parameters indicate that the bridge under test is a long-span bridge, determining the excitation mode as a pulsating mode; and when the span parameters indicate that the bridge under test is a medium-span bridge, determining the excitation mode as a running car mode.

[0017] This application, by adopting the above technical solution, demonstrates that for long-span bridges with greater flexibility, the pulsed testing method better captures their characteristics, facilitating radar data acquisition. For medium- and small-span bridges with less flexibility, the running car testing method provides more complete data acquisition by millimeter-wave radar compared to the pulsed method. When using millimeter-wave radar for wireless data acquisition, appropriately selecting the excitation method helps improve the completeness of the acquired data and ensures the accuracy of the measurement parameters.

[0018] Optionally, the step of determining the position parameters and quantity parameters in the setting parameters based on the bridge structure and the vibration order in the aforementioned method includes: determining the number and location of the measuring points according to the bridge structure and the vibration order; and determining the position parameters and quantity parameters in the setting parameters according to the operating parameters of the test radar and the number and location of the measuring points.

[0019] This application, by adopting the above technical solution, first determines the location and number of each measuring point based on the bridge structure and vibration order. Then, based on the location and number of each measuring point and the effective acquisition range of the test radar, it determines the location and number of test radars. The test radars are rationally arranged to ensure that the measurement parameters of each measuring point can be completely acquired, while improving the utilization rate of the test radars and reducing equipment costs.

[0020] Optionally, after the step of determining the position parameters and quantity parameters in the setting parameters based on the bridge structure and the vibration order in the aforementioned method, the method further includes: obtaining the environmental parameters of the bridge under test; determining the deployment conditions of each measuring point according to the environmental parameters; and determining the radar type parameter in the setting parameters according to the correspondence between the test radar and the measuring point, wherein the radar type parameter includes one of corner reflector radar and wireless distributed radar.

[0021] This application, by adopting the above technical solution, determines the deployment conditions for each measuring point based on the acquired environmental parameters. The test radar can collect data from one or more measuring points. Based on the mapping relationship between the test radar and each measuring point, and considering the deployment conditions of each measuring point, the type of test radar to be used is determined. The deployment steps for corner reflector radar are cumbersome, making it suitable for measuring points with poor deployment conditions. The deployment steps for wireless distributed radar are simpler, making it suitable for measuring points with good deployment conditions. Appropriately selecting the radar type for each measuring point helps the test radar collect data more accurately and improves data acquisition efficiency.

[0022] Optionally, the step of obtaining the vibration order of the bridge under test in the aforementioned method includes: obtaining the mapping relationship between bridge type and vibration order; and determining the vibration order of the bridge under test based on the bridge type in the bridge structure and the mapping relationship.

[0023] Optionally, the step of generating the dynamic deflection time history curves of each measuring point of the bridge under test based on the test scheme includes: determining the effective time parameters of the measurement parameters of each measuring point according to the excitation method; obtaining all measurement parameters of each measuring point based on the test scheme; determining the effective measurement parameters for generating the dynamic deflection time history curves from all the measurement parameters according to the effective time parameters; and generating the dynamic deflection time history curves of each measuring point according to the effective measurement parameters.

[0024] Optionally, the step of generating the dynamic deflection time history curves of each measuring point of the bridge under test based on the test scheme in the aforementioned method includes: determining the effective time parameters of the measurement parameters of each measuring point according to the excitation method; obtaining all measurement parameters of each measuring point based on the test scheme; determining the effective measurement parameters for generating the dynamic deflection time history curves from all the measurement parameters according to the effective time parameters; and generating the dynamic deflection time history curves of each measuring point according to the effective measurement parameters.

[0025] This application, by adopting the above-mentioned technical solution, addresses the issue that different excitation methods have varying impacts on the characteristics of the bridge under test, potentially leading to low accuracy in the collected measurement parameters. By determining the effective measurement parameters for each measuring point based on their effective time parameters, the effective measurement parameters for each measuring point are determined, generating dynamic deflection time history curves for each point. Selecting effective measurement parameters improves the accuracy of the dynamic deflection time history curves for each measuring point, facilitating subsequent analysis and processing based on these curves.

[0026] Optionally, the step of determining the model input parameter time history curve of each measuring point based on the dynamic deflection time history curve of each measuring point in the aforementioned method includes: generating velocity time history curves and acceleration time history curves of each measuring point based on the dynamic deflection time history curves of each measuring point; obtaining the velocity spectrum diagram of the velocity time history curve and the acceleration spectrum diagram of the acceleration time history curve; and determining the model input parameter time history curve from the velocity time history curve or the acceleration time history curve based on the spectral value distribution of the velocity spectrum diagram and the spectral value distribution of the acceleration spectrum diagram.

[0027] This application employs the aforementioned technical solution to process the dynamic deflection time history curves at each measuring point, obtaining the velocity and acceleration time history curves for each point. Spectral analysis is then performed on the velocity and acceleration time history curves to generate corresponding spectrum diagrams. The velocity or acceleration time history curve corresponding to the spectrum diagram with high spectral completeness is selected as the model input parameter time history curve for each measuring point. The model input parameter time history curves selected using this solution have higher completeness, resulting in higher accuracy of the measurement parameters at each measuring point, which is beneficial for subsequent data analysis.

[0028] Optionally, the model input parameter time history curves in the aforementioned method include the velocity time history curve and acceleration time history curve corresponding to the dynamic deflection time history curve; the step of determining the modal parameters of the bridge under test based on the modal parameter test model corresponding to the bridge under test and the model input parameter time history curves of each measuring point includes: obtaining a first modal parameter based on the modal parameter test model corresponding to the bridge under test and the velocity time history curves of each measuring point; obtaining a second modal parameter based on the modal parameter test model corresponding to the bridge under test and the acceleration time history curves of each measuring point; and determining the modal parameters of the bridge under test from the first modal parameter or the second modal parameter based on the evaluation effect of the first modal parameter and the second modal parameter.

[0029] This application employs the aforementioned technical solution, analyzing the velocity time history curves of each measuring point based on the modal parameter test model corresponding to the bridge under test to obtain the first modal parameters. Based on the same model, the acceleration time history curves of each measuring point are analyzed to obtain the second modal parameters. By comparing the first and second modal parameters, the more accurate first or second modal parameter is selected as the modal parameters for the bridge under test. Differential processing of the dynamic deflection time history curve solves the problem that conventionally acquired dynamic displacement signals are difficult to directly use in modal analysis within the bridge modal parameter test model, thus improving the accuracy and efficiency of parameter processing.

[0030] Secondly, the present invention provides a bridge modal testing system, the system comprising:

[0031] The first determination module determines the test plan based on the bridge structure of the bridge to be tested;

[0032] The analysis module generates the dynamic deflection time history curves of each measuring point of the bridge under test based on the test plan.

[0033] The second determination module determines the model input parameter time history curve for each measuring point based on the dynamic deflection time history curve for each measuring point.

[0034] The output module outputs the modal parameters of the bridge under test based on the modal parameter test model corresponding to the bridge under test and the time history curves of the model input parameters at each measuring point.

[0035] In summary, this application includes the following beneficial technical effects:

[0036] This application collects measurement parameters at various measuring points of the bridge under test using radar, and obtains the velocity / acceleration parameters of each measuring point based on these measurement parameters, thereby realizing the testing of the bridge's modal parameters. In this application, the use of wireless radar improves the flexibility of equipment deployment at various measuring points of the bridge under test, solves the problem of certain limitations of conventional technology using wired equipment deployment, and alleviates the dependence on sensor equipment. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the first process of the bridge modal parameter testing method according to an embodiment of this application.

[0038] Figure 2 This is a schematic diagram of the bridge modal testing system according to an embodiment of this application.

[0039] Figure 3 This is a schematic diagram of the second process of the bridge modal parameter testing method according to an embodiment of this application.

[0040] Figure 4 This is a time history curve of dynamic deflection of the bridge modal testing method according to an embodiment of this application.

[0041] Explanation of reference numerals in the attached diagram: 11. First determination module; 12. Analysis module; 13. Second determination module; 14. Output module. Detailed Implementation

[0042] To enable those skilled in the art to better understand the technical solutions in this specification, the technical solutions in the embodiments of this specification will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0043] In the description of the embodiments of this application, the words "for example" or "for instance" are used to indicate examples, illustrations, or explanations. Any embodiment or design that is described as "for example" or "for instance" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design options. Rather, the use of the words "for example" or "for instance" is intended to present the relevant concepts in a specific manner.

[0044] In the description of the embodiments of this application, the term "multiple" means two or more. For example, multiple systems means two or more systems, and multiple screen terminals means two or more screen terminals. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the indicated technical features. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature. The terms "comprising," "including," "having," and variations thereof all mean "including but not limited to," unless otherwise specifically emphasized.

[0045] One embodiment of this application provides a method for testing bridge modal parameters, applied in a server. For example... Figure 1 As shown, the method includes steps S101-S104.

[0046] Step S101: Determine the test plan based on the bridge structure of the bridge to be tested.

[0047] In this application, the bridge to be tested can be a bridge selected by the user on-site or remotely. Its type can be a simply supported beam bridge, a non-simply supported beam bridge, an arch bridge, a cable-stayed bridge, or a suspension bridge. The bridge structure can be a long-span bridge structure or a medium-span bridge structure. Long-span bridges generally refer to bridges with a span of 50 meters or more, typically using box girder or arch bridges with a large height and depth. Medium-span bridges generally refer to bridges with a span of less than 50 meters. The testing scheme can involve using 20 corner reflector radars to test a 100-meter suspension bridge. After deploying the 20 corner reflector radars, data can be collected from 30 deformation measurement points. The excitation method uses an arterial excitation method.

[0048] In this application, prior to step S101, the method further includes: obtaining the bridge structure of the bridge to be tested. Specifically, this can be achieved by: obtaining a design entity model of the bridge to be tested; determining the bridge structure and parameters based on the design entity model; and thus determining the test plan for the bridge. In another scenario, the method can be based on a photograph of the bridge to be tested, using a neural network to extract features from the photograph to determine the bridge type, thereby determining the test plan for the bridge. Alternatively, the method can involve: scanning the bridge to be tested using radar wireless signals to obtain the structural features of the bridge, thereby determining the test plan for the bridge.

[0049] Specifically, the test plan includes the setting parameters of the test radar and the excitation method. The test tool is a wireless radar, and the excitation method is determined according to the bridge structure.

[0050] Step S102: Based on the test plan, generate the dynamic deflection time history curves of each measuring point of the bridge under test.

[0051] In this application, each measuring point is a structural point of the bridge to be measured. Each measuring point can be determined based on factors such as the bridge structure type, length, span, construction, and degree of deformation. The location of the measuring point can be any part of the bridge body.

[0052] In this application, the dynamic deflection time history curve represents the curve composed of the vertical displacement value of the deflection test point and time during the dynamic testing process of the bridge. Dynamic deflection is the same as dynamic displacement. The horizontal axis of the dynamic deflection time history curve represents time, and the vertical axis represents displacement. Therefore, the dynamic deflection time history curve contains the relationship between the bridge's measured parameters of displacement, velocity, and acceleration.

[0053] Specifically, the test plan is executed, and corresponding test radars are deployed at each test point. The test radars will then automatically collect the measurement parameters of each test point. Based on the measurement parameters, the system generates the dynamic deflection time history curves of each test point.

[0054] Step S103: Determine the model input parameter time history curves for each measuring point based on the dynamic deflection time history curves for each measuring point.

[0055] This application acquires dynamic displacement signals. Since dynamic displacement signals are low-order variables, they are difficult to directly use in modal parameter testing models for modal analysis. This step involves differentiating the dynamic deflection time history curve to obtain higher-order velocity and acceleration signals from the dynamic displacement signals. These signals are then easily substituted into the modal parameter testing model for modal analysis, improving the accuracy of the output modal parameters.

[0056] In this application, the model input parameter time history curve is obtained by differential processing of the dynamic deflection time history curve. The horizontal axis of the model input parameter time history curve is time, and the vertical axis is the velocity or acceleration of the displacement component after first or second order differential processing. Therefore, the model input parameter time history curve has a higher order than the model input parameter time history curve, which is more conducive to data analysis.

[0057] Step S104: Based on the modal parameter test model corresponding to the bridge under test and the time history curves of the model input parameters at each measuring point, output the modal parameters of the bridge under test.

[0058] In this application, the modal parameter test model is used to perform modal analysis on the time history curve of the input model parameters and output the modal parameters of the bridge under test. The modal parameters include: mode shape, natural frequency and damping ratio.

[0059] The modal parameter testing model is established based on the bridge structure of the bridge under test and the number and location of each measuring point. Specifically, each measuring point should be coupled with the nodes of the modal parameter testing model, and the direction of velocity and acceleration needs to be considered during coupling.

[0060] Specifically, a suitable dynamic deflection time history curve is selected as the model input parameter time history curve of the modal parameter test model corresponding to the bridge under test, and finally the modal parameters of the bridge under test are output after modal analysis.

[0061] In summary, this application uses radar to collect measurement parameters at each measuring point, which differs from the traditional method of using wired equipment to collect measurement parameters at each measuring point. This makes it easier to determine the deployment location and quantity of equipment. The radar used is a millimeter-wave radar, which improves the accuracy of the collected test parameters, solves the problem of certain limitations of conventional technologies that use wired equipment deployment, and reduces the dependence on sensor equipment.

[0062] In one embodiment, step S101 of the aforementioned method includes: obtaining the vibration order of the bridge under test; determining the excitation method based on the span parameters in the bridge structure; determining the position parameters and quantity parameters in the setting parameters based on the bridge structure and the vibration order; and outputting a test plan based on the excitation method, position parameters, and quantity parameters.

[0063] In this application, the vibration order of the bridge under test can be 1st, 3rd, or 9th. For simply supported beam bridges, the vibration order to be tested is 1st; for non-simply supported beam bridges and arch bridges, the vibration order to be tested and analyzed is 3rd; for long-span bridge structures such as cable-stayed bridges and suspension bridges, the vibration order to be tested and analyzed is 9th. Therefore, this application can directly determine the vibration order based on the bridge structure, such as whether it is a simply supported beam bridge, a non-simply supported beam bridge, an arch bridge, a cable-stayed bridge, or a suspension bridge.

[0064] In one embodiment, the step of determining the excitation mode based on the span parameters in the bridge structure in the aforementioned method includes: when the span parameters indicate that the bridge under test is a long-span bridge, determining the excitation mode as a pulsating mode; and when the span parameters indicate that the bridge under test is a medium- or small-span bridge, determining the excitation mode as a running car mode.

[0065] In this application, the span parameter is a measured value for bridges, based on the length of the bridge's centerline between two piers or the length of the bridge's centerline between the pier centerline and the leading edge of the abutment back. Span parameters can be 20m, 50m, and 100m, etc. Based on the span parameter, this application classifies bridges into large-span bridges and medium-to-small-span bridges. The excitation method can be either a running car method or a pulsating method. By using these two methods to excite the bridge to produce vibrations, the characteristics of the bridge are highlighted, making it easier for the test radar to collect test signals.

[0066] In this application, the "vehicle running method" involves selecting vehicles of appropriate weight and running them at different speeds on the bridge deck, based on the bridge's material and structure. For example, a 10-ton vehicle could be used to run on a small-to-medium span bridge at 30 km / h to excite the bridge's characteristics. The "pulsation method" involves measuring the minute vibration responses of the bridge span structure caused by random loads such as wind loads, ground tremors, and water flow at the bridge site, under conditions where there are no traffic loads on the bridge under test and no irregular vibration sources near the bridge.

[0067] In this application, the span parameter of the bridge under test characterizes the flexibility of the bridge. The ratio of the maximum displacement to the span parameter directly reflects the flexibility of the bridge. The larger the span parameter, the smaller the ratio, and the greater the flexibility. Bridges with a ratio less than 2.5 are considered flexible bridges. Small and medium-span bridges have lower flexibility, while large-span bridges have higher flexibility. Therefore, this application essentially determines the excitation method of the bridge based on its flexibility.

[0068] For medium- and small-span bridges, the modal frequencies are relatively high. If a pulsating method is used, the main peak of the spectrum is not prominent. Furthermore, the pulsating signal is inherently weak, and the influence of background noise is significant, making it difficult to accurately identify the vibration information of the bridge structure. Therefore, a vehicle-driven method is used for excitation. Utilizing the residual vibration of the bridge after a vehicle crosses the bridge, the collected measurement parameters better reflect the bridge's characteristics. Large-span bridges have greater flexibility, and the pulsating method is more effective for testing. In this application, when using millimeter-wave radar to collect data wirelessly, the appropriate selection of the excitation method helps improve the integrity of the millimeter-wave radar data and ensures the accuracy of the measurement parameters.

[0069] In one embodiment, the step of determining the position and quantity parameters in the setting parameters based on the bridge structure and vibration order in the aforementioned method includes: determining the number and location of measuring points according to the bridge structure and vibration order; and determining the position and quantity parameters in the setting parameters according to the operating parameters of the test radar and the number and location of the measuring points.

[0070] In this application, the number and location of measurement points do not correspond one-to-one with the number and location of test radars. The design can be tailored to factors such as measurement accuracy and cost control. For example, to improve measurement accuracy, if the bridge under test has three measurement points distributed in different locations, and eight test radars are used, the first measurement point requires simultaneous measurement by four test radars, the second by five, and the third by six. Data reuse from these eight radars improves measurement accuracy. Alternatively, to reduce measurement costs, some test radars can measure the dynamic displacement of multiple measurement points. Assuming there are ten measurement points, only three radars need to be set up, and the radar locations can be rationally arranged based on the measurement point locations and radar coverage areas.

[0071] In one embodiment, after determining the measurement points, the aforementioned method determines the location and number of millimeter-wave radars to be deployed based on the effective operating range of the millimeter-wave radar, ensuring that the measurement parameters of each measurement point can be acquired by the millimeter-wave radar. One radar can acquire measurement parameters from multiple measurement points, and the measurement parameters of one measurement point can also be acquired by multiple radars. When a millimeter-wave radar corresponds to a large number of measurement points, due to the limitation of the radar beam angle range, a single radar cannot test simultaneously, requiring the deployment of multiple radars for synchronous testing via clock synchronization. Reasonable deployment of test radars ensures that the measurement parameters of each measurement point can be completely acquired, while improving the utilization rate of the test radars and reducing equipment wear and tear.

[0072] In one embodiment, after determining the position parameters and quantity parameters in the setting parameters based on the bridge structure and vibration order, the aforementioned method further includes: obtaining the environmental parameters of the bridge under test; determining the deployment conditions of each measuring point based on the environmental parameters; and determining the radar type parameter in the setting parameters based on the correspondence between the test radar and the measuring point, wherein the radar type parameter includes one of corner reflector radar and wireless distributed radar.

[0073] In this application, environmental parameters can be environmental factors that affect bridge testing, such as whether there is water accumulation or other industrial equipment under the bridge, whether there are other load-bearing items on the bridge deck, and whether there are stable vibration sources around the bridge.

[0074] The method for determining the deployment conditions of bridges based on environmental factors can be as follows: when the test radar corresponding to the test point is in a situation where there is no water under the bridge or it is easy to set up for testing, multiple wireless distributed radars are used to form a distributed test system, and the direct wave of electromagnetic waves is used for synchronous testing; when the test radar corresponding to the test point cannot be tested using the direct wave, corner reflector radars need to be deployed at the test point location to increase the reflection energy of electromagnetic waves.

[0075] The two millimeter-wave radars can be selected based on the bridge site conditions. For situations where there is water under the bridge or where it is inconvenient to deploy testing equipment below the corresponding test points, a method of deploying measuring points using corner reflectors within the bridge structure can be adopted. For situations where it is easy to deploy testing equipment under the bridge, a wirelessly distributed millimeter-wave radar testing system can be used for testing. In this application, when the two millimeter-wave radars sample the signals, their sampling frequency should be greater than or equal to 10 times the vibration order analysis frequency.

[0076] Furthermore, based on the correspondence between the test radar and each measurement point, the type parameters of the test radar are determined. The test radar can collect data from one or more measurement points; therefore, based on the mapping relationship between the test radar and each measurement point, and considering the deployment conditions of each measurement point, the type of test radar to be used is determined. The deployment steps of corner reflector radar are cumbersome and suitable for measurement points with poor deployment conditions; while the deployment steps of wireless distributed radar are simpler and suitable for measurement points with good deployment conditions. This application provides a reasonable selection of radar type for each measurement point, which is beneficial for the test radar to collect data from each measurement point more accurately and improves the efficiency of data collection.

[0077] In one embodiment, the step of obtaining the vibration order of the bridge under test in the aforementioned method includes: obtaining the mapping relationship between bridge type and vibration order; and determining the vibration order of the bridge under test based on the bridge type in the bridge structure and the mapping relationship.

[0078] In this application, the mapping relationship between bridge type and vibration order can be as follows: for simply supported beam bridges, the vibration order to be tested is 1; for non-simply supported beam bridges and arch bridges, the vibration order to be tested and analyzed is 3; for cable-stayed bridges, suspension bridges and other long-span bridge structures, the vibration order to be tested and analyzed is 9.

[0079] The vibration order required for bridge modal parameter testing is determined based on the bridge structure. Different bridge structures have different required orders. Vibration orders are divided into 1st, 3rd, and 9th orders, corresponding to different types of bridges. The vibration order of the bridge to be tested is determined according to the type of bridge to be tested, which facilitates subsequent data analysis based on the vibration order and improves the accuracy of the analysis data.

[0080] In one embodiment, step S102 of the aforementioned method includes: determining the effective time parameter of the measurement parameters of each measuring point according to the excitation method; obtaining all measurement parameters of each measuring point based on the test plan; determining the effective measurement parameter for generating the dynamic deflection time history curve from all measurement parameters according to the effective time parameter; and generating the dynamic deflection time history curve of each measuring point according to the effective measurement parameter.

[0081] In this application, the effective time parameter is the effective time for collecting and measuring parameters. For example, in a sports car test, the measurement time is 0 to 60 seconds, and the sports car leaves the bridge at the 30th second. Therefore, the effective time parameter is 30 to 60 seconds.

[0082] This application collects measurement parameters according to the test plan. The signal acquisition time of each test radar at the measurement point should be synchronized. For example, when multiple test radars acquire data from the same measurement point, the acquired data should be synchronized in time to facilitate subsequent data analysis. When using a pulsed test excitation method, if the test radars acquire the signal at the measurement point in time, the acquired measurement parameters are all valid measurement parameters. If the test radars acquire the signal at the measurement point in time are not synchronized, the acquired measurement parameters are invalid measurement parameters and need to be re-acquired. When using a running car test excitation method, the added mass of the vehicle will affect the accuracy of the measurement parameters. Therefore, the valid time parameter is the time after the vehicle leaves. Then, it is determined whether the measurement parameters acquired by each test radar are synchronized in time after the vehicle leaves. The measurement parameters that are synchronized in time are valid measurement parameters.

[0083] In this application, different excitation methods have different effects on the characteristics of the bridge under test, which may lead to low accuracy of the collected measurement parameters. Therefore, this application selects effective measurement parameters to improve the accuracy of the dynamic deflection time history curves of each measuring point, so as to facilitate subsequent analysis and processing based on the dynamic deflection time history curves.

[0084] In one embodiment, step S103 of the aforementioned method includes the step of determining the dynamic deflection time history curve of each measuring point and the step of determining the model input parameter time history curve of each measuring point, including: generating the velocity time history curve and acceleration time history curve of each measuring point based on the dynamic deflection time history curve of each measuring point; obtaining the velocity spectrum diagram of the velocity time history curve and the acceleration spectrum diagram of the acceleration time history curve; and determining the model input parameter time history curve from the velocity time history curve or the acceleration time history curve based on the spectral value distribution of the velocity spectrum diagram and the spectral value distribution of the acceleration spectrum diagram.

[0085] In this application, the spectral value distribution of the spectrum is a frequency distribution diagram. For example, if it is necessary to collect a signal with a frequency of 50 Hz at a certain measurement point, and the velocity spectrum has a 50 Hz signal but the acceleration spectrum does not have a 50 Hz signal, then the velocity time history curve is selected as the model input parameter time history curve.

[0086] Specifically, step S103 can involve generating dynamic deflection time history curves for each measuring point based on the effective measurement parameters of each point. Then, the dynamic deflection time history curves are differentiated once to obtain velocity time history curves, and differentiated twice to obtain acceleration time history curves. Next, spectral analysis is performed on the velocity and acceleration time history curves respectively to generate velocity and acceleration spectrum diagrams. Finally, the spectral distributions of the two spectrum diagrams are compared, and the velocity or acceleration time history curve corresponding to the spectrum diagram containing the desired spectral frequencies is selected as the model input parameter time history curve. The model input parameter time history curves selected using this scheme have higher completeness, and the measurement parameters at each measuring point have higher accuracy, which is beneficial for subsequent data analysis.

[0087] As analyzed above, the time history curves of the model input parameters include the velocity time history curve and acceleration time history curve corresponding to the dynamic deflection time history curve. Therefore, step S104 mentioned above includes: obtaining the first modal parameters based on the modal parameter test model corresponding to the bridge under test and the velocity time history curves of each measuring point; obtaining the second modal parameters based on the modal parameter test model corresponding to the bridge under test and the acceleration time history curves of each measuring point; and determining the modal parameters of the bridge under test from the first modal parameters or the second modal parameters based on the evaluation effect of the first modal parameters and the second modal parameters.

[0088] Specifically, the velocity time history curve and acceleration time history curve obtained by differentiating the dynamic deflection time history curve are first analyzed modally using the modal parameter test model corresponding to the bridge under test, respectively, to generate the first modal parameter and the second modal parameter. Then, the theoretical values ​​of the modal parameters are calculated. Based on the theoretical values ​​of the modal parameters and the mode shape distribution of the bridge under test, the first modal parameter and the second modal parameter are compared, and the one with better evaluation effect is selected as the final modal parameter result.

[0089] like Figure 2 As shown, it illustrates a module flow diagram of a bridge modal testing system provided in an embodiment of this application, consisting of... Figure 2 It can be seen that the system includes:

[0090] The first determining module 11 is specifically used to: determine the test plan based on the bridge structure of the bridge to be tested;

[0091] Analysis module 12 is specifically used to: generate dynamic deflection time history curves for each measuring point of the bridge under test based on the test plan;

[0092] The second determining module 13 is specifically used to: determine the model input parameter time history curve of each measuring point based on the dynamic deflection time history curve of each measuring point;

[0093] The output module 14 is specifically used to output the modal parameters of the bridge under test based on the modal parameter test model corresponding to the bridge under test and the time history curve of the model input parameters of each measuring point.

[0094] In another embodiment, the first determining module 11 is specifically used to: determine the position parameters and quantity parameters in the setting parameters based on the bridge structure and vibration order; the output module 14 is specifically used to: output the test plan based on the excitation method, position parameters and quantity parameters.

[0095] In another embodiment, the first determining module 11 is specifically used to: determine the excitation mode as a pulsating mode when the span parameter indicates that the bridge under test is a long-span bridge; the first determining module 11 is specifically used to: determine the excitation mode as a running car mode when the span parameter indicates that the bridge under test is a medium-span bridge.

[0096] In another embodiment, the first determining module 11 is specifically used to: determine the deployment conditions of each measuring point according to environmental parameters; the first determining module 11 is specifically used to: determine the radar type parameter in the setting parameters according to the correspondence between the test radar and the measuring point.

[0097] In another embodiment, the first determining module 11 is specifically used to: determine the vibration order of the bridge under test based on the bridge type and mapping relationship in the bridge structure.

[0098] In another embodiment, the first determining module 11 is specifically used to: determine the effective time parameter of the measurement parameters of each measuring point according to the excitation method; the first determining module 11 is specifically used to: determine the effective measurement parameter for generating the dynamic deflection time history curve from all the measurement parameters according to the effective time parameter; the analysis module 12 is specifically used to: generate the dynamic deflection time history curve of each measuring point according to the effective measurement parameter.

[0099] In another embodiment, the analysis module 12 is specifically used to: generate the velocity time history curve and acceleration time history curve of each measuring point based on the dynamic deflection time history curve of each measuring point; the second determination module 13 is specifically used to: determine the model input parameter time history curve from the velocity time history curve or acceleration time history curve based on the spectral value distribution of the velocity spectrum diagram and the spectral value distribution of the acceleration spectrum diagram.

[0100] In another embodiment, the analysis module 12 is specifically used to: obtain the first modal parameters based on the modal parameter test model corresponding to the bridge under test and the velocity time history curves of each measuring point; the analysis module 12 is specifically used to: obtain the second modal parameters based on the modal parameter test model corresponding to the bridge under test and the acceleration time history curves of each measuring point; the second determination module 13 is specifically used to: determine the modal parameters of the bridge under test from the first modal parameters or the second modal parameters based on the evaluation effect of the first modal parameters and the second modal parameters.

[0101] It should be noted that the above embodiments of the apparatus are only illustrated by the division of the above functional modules. In practical applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above. In addition, the apparatus and method embodiments provided in the above embodiments belong to the same concept, and the specific implementation process can be found in the method embodiments, which will not be repeated here.

[0102] like Figure 3 As shown, it illustrates a method for testing bridge modal parameters according to an embodiment of this application, the method including steps S201-S204.

[0103] Step S201: Investigate relevant information about the bridge to be tested and determine the test plan.

[0104] In this application, relevant materials may include engineering drawings, photographs, environmental conditions around the bridge to be tested, and testing tools such as radar. The testing plan for the bridge to be tested is determined based on the surveyed data. The testing plan includes: the type, location, and quantity of testing tools deployed, and the excitation method. The excitation method may be a running car method or a pulsed method, etc.

[0105] Step S202: Execute the test plan and collect test signals.

[0106] In this application, the test signal is a dynamic displacement signal. The sampling frequency of the acquired signal is 10 times the vibration order, the acquired signals need to be time-synchronized, and at least 3 sets of test signals need to be acquired by exciting the bridge under test; the test signals should also be selected based on the excitation method and the test signals acquired within the effective time period.

[0107] Step S203: Establish a modal parameter model and perform modal analysis on the test signal.

[0108] In this application, the test signal is a dynamic displacement signal, which is differentiated to obtain velocity and acceleration signals. Since the dynamic displacement signal is a low-order variable signal, it is difficult to use directly for modal analysis; differentiation is required to obtain higher-order velocity and acceleration signals.

[0109] Specifically, modal analysis requires modeling a modal parameter test model. The construction of points, lines, and surfaces in the model needs to be combined with the vibration order, bridge structure, and the location and number of measuring points. Each measuring point should be coupled with the nodes of the modal parameter test model, and the direction of velocity and acceleration needs to be considered during coupling.

[0110] This application acquires dynamic displacement signals to obtain dynamic displacement (i.e., dynamic deflection). Since dynamic displacement signals are low-order variables, they are difficult to directly perform modal analysis using modal parameter testing models. Therefore, this application performs differential processing on the dynamic deflection time history curve. The dynamic displacement signals are processed to obtain high-order velocity and acceleration signals, which are easier to substitute into the modal parameter testing model for modal analysis, thereby improving the accuracy of the output modal parameters.

[0111] Step S204: Output the modal analysis results.

[0112] In this application, the output modal analysis results can be modal parameters such as the mode shape, damping, and natural frequency of the bridge structure.

[0113] like Figure 4 As shown, it illustrates the dynamic deflection time history curve of a bridge modal testing method provided in an embodiment of this application. Figure 4 middle,

[0114] The horizontal axis represents time, with time measured in seconds; the vertical axis represents displacement, with displacement measured in millimeters. For example... Figure 4 As shown, measurements from a specific measuring point in the bridge modal parameter test, spanning a time period of 32 to 38 seconds, are extracted to generate the corresponding dynamic deflection time history curve. Figure 4 It can be seen that the bridge under test was excited by the sports car between 32 and 33 seconds, and after the sports car left the bridge between 34 and 35 seconds, the residual vibration basically weakened back to its initial state. When using a sports car to excite the bridge under test, the weight of the vehicle itself will affect the measurement parameters. Figure 4 It can be seen that the displacement of the measuring point on the bridge under test between 33 and 35 seconds is affected by the weight of the sports car, and the amplitude of the dynamic displacement is relatively large; therefore, the effective measurement parameters of this measuring point are the measurement parameters between 35 and 38 seconds.

[0115] Figure 4 It clearly shows the trend of displacement of the bridge under test over time after excitation, which is convenient for professionals to evaluate the dynamic characteristics of the bridge structure.

[0116] The above are merely exemplary embodiments of this disclosure and should not be construed as limiting the scope of this disclosure. Any equivalent changes and modifications made in accordance with the teachings of this disclosure shall still fall within the scope of this disclosure. Other embodiments of this disclosure will readily conceive of those skilled in the art upon consideration of the specification and the disclosure of practical truths.

[0117] This application is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not described in this disclosure. The specification and embodiments are to be considered exemplary only, and the scope and spirit of this disclosure are defined by the claims.

Claims

1. A method for testing bridge modal parameters, characterized in that, include: Determine the testing plan based on the bridge structure of the bridge to be tested; The test plan includes the setting parameters of the test radar in the test system and the excitation method; Based on the aforementioned test scheme, the dynamic deflection time history curves of each measuring point of the bridge under test are generated. Based on the dynamic deflection time history curves of each measuring point, determine the model input parameter time history curves of each measuring point; Based on the modal parameter test model corresponding to the bridge under test and the time history curves of the model input parameters at each measuring point, the modal parameters of the bridge under test are output. Obtain the vibration order of the bridge under test; The excitation method is determined based on the span parameters in the bridge structure; Based on the bridge structure and the vibration order, determine the positional and quantity parameters in the setting parameters; Based on the excitation method, the position parameters, and the quantity parameters, the test plan is output; The step of obtaining the vibration order of the bridge under test includes: Obtain the mapping relationship between bridge type and vibration order; Based on the bridge type in the bridge structure and the mapping relationship, the vibration order of the bridge under test is determined. The step of determining the model input parameter time history curve for each measuring point based on the dynamic deflection time history curve for each measuring point includes: Based on the dynamic deflection time history curves of each measuring point, generate the velocity time history curves and acceleration time history curves of each measuring point; Obtain the velocity spectrum of the velocity time history curve and the acceleration spectrum of the acceleration time history curve; Based on the spectral distribution of the velocity spectrum and the spectral distribution of the acceleration spectrum, the time history curve of the model input parameters is determined from the velocity time history curve or the acceleration time history curve; The model input parameter time history curves include the velocity time history curve and acceleration time history curve corresponding to the dynamic deflection time history curve; the step of determining the modal parameters of the bridge under test based on the modal parameter test model corresponding to the bridge under test and the model input parameter time history curves of each measuring point includes: The first modal parameters are obtained based on the modal parameter test model corresponding to the bridge under test and the velocity time history curves of each measuring point. The second modal parameters are obtained based on the modal parameter test model corresponding to the bridge under test and the acceleration time history curves of each measuring point. Based on the evaluation results of the first modal parameters and the second modal parameters, the modal parameters of the bridge under test are determined from the first modal parameters or the second modal parameters; After the step of determining the positional and quantity parameters in the setting parameters based on the bridge structure and the vibration order, the method further includes: Obtain the environmental parameters of the bridge under test; Determine the deployment conditions for each measuring point based on the aforementioned environmental parameters; Based on the correspondence between the test radar and the measurement point, the radar type parameter in the setting parameters is determined. The radar type parameter includes one of corner reflector radar and wireless distributed radar.

2. The bridge modal parameter testing method according to claim 1, characterized in that, The step of determining the excitation method based on the span parameters in the bridge structure includes: When the span parameter characterizes the bridge under test as a long-span bridge, the excitation mode is determined to be a pulsating mode; When the span parameter characterizes the bridge under test as a small to medium span bridge, the excitation mode is determined to be the running car mode.

3. The bridge modal parameter testing method according to claim 1, characterized in that, The step of determining the positional and quantity parameters in the setting parameters based on the bridge structure and the vibration order includes: The number and location of the measuring points are determined based on the bridge structure and the vibration order. Based on the operating parameters of the test radar, as well as the number and location of the measuring points, the position parameters and quantity parameters in the setting parameters are determined.

4. The bridge modal parameter testing method according to claim 1, characterized in that, The step of generating the dynamic deflection time history curves of each measuring point of the bridge under test based on the test scheme includes: Based on the excitation method, determine the effective time parameters of the measurement parameters at each measuring point; Based on the aforementioned test plan, all measurement parameters for each measuring point are obtained; Based on the effective time parameter, determine the effective measurement parameter for generating the dynamic deflection time history curve from all the measurement parameters; Based on the effective measurement parameters, the dynamic deflection time history curves of each measuring point are generated.

5. A bridge modal testing system for implementing the bridge modal parameter testing method as described in any one of claims 1-4, characterized in that, The system includes: The first determination module determines the test plan based on the bridge structure of the bridge to be tested; The analysis module generates the dynamic deflection time history curves of each measuring point of the bridge under test based on the test plan. The second determination module determines the model input parameter time history curve for each measuring point based on the dynamic deflection time history curve for each measuring point. The output module outputs the modal parameters of the bridge under test based on the modal parameter test model corresponding to the bridge under test and the time history curves of the model input parameters at each measuring point.

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