Damping test identification method for rigid contact network suspension device

Abstract

The invention is applicable to the field of rigid catenary part tests, and provides a damping test identification method for a rigid catenary suspension device, which comprises the following steps of: installing a non-contact laser signal sensor for measuring a vibration displacement time travel curve of the rigid catenary suspension device, and applying a vertically downward load to the rigid catenary suspension device, extracting and analyzing a vibration displacement time travel curve of the suspension device to identify the rigidity of the rigid contact network suspension device; an impact force hammer is adopted to input impact excitation to the rigid contact network suspension device, suspension device vibration displacement time history data recorded by a laser displacement sensor are extracted and analyzed, and a free vibration attenuation method is utilized to calculate damping and mass of the rigid contact network suspension device. According to the rigid contact network suspension device damping test identification method provided by the invention, the damping and the mass of the rigid contact network suspension device are determined through a method of combining test and free vibration attenuation, and effective support can be provided for research on structural characteristics of a rigid contact network.

Description

Technical Field

[0001] The invention relates to the field of rigid contact network component testing, and in particular to a rigid contact network suspension device damping test identification method. Background Art

[0002] In the tunnel railways and urban rail transit tunnel lines in the central and western mountainous areas, the rigid contact network is an important way for trains to obtain continuous and stable electricity, and its dynamic interaction characteristics with the pantograph directly affect the current-collecting performance of the train. At present, the operating speed of domestic rigid contact network lines is below 160 km / h, and the existing speed levels are difficult to meet the development needs of high-speed and efficient transportation of mountain railways and urban rail transit in my country. In order to improve the service reliability of rigid contact networks under high-speed conditions, it is necessary to conduct a more in-depth study on the structural characteristics of its components. The present invention accurately identifies the damping and mass of the rigid contact network suspension device by conducting field tests on the rigid contact network suspension device, providing theoretical support for the design of high-speed rigid contact networks.

[0003] The rigid contact network is an important way for electrified trains in tunnels to obtain electrical energy. At present, the research on the pantograph-catenary system mainly relies on finite element numerical simulation. L. Chen et al. (L. Chen, F. Duan, Y. Song, et al. Assessment of dynamic interaction performance of high-speed pantograph and overhead conductor rail system[J]. IEEE Transactions on Instrumentation and Measurement, 2021, 71: 1-14) established an accurate rigid contact network finite element model using the absolute node coordinate method (ANCF). At the same time, they pointed out that the model can be properly linearized to improve the calculation efficiency. In addition, they introduced global contact line wear considering the wavelength and amplitude of wear, and analyzed its impact on the current-collecting performance of the 200 km / h high-speed pantograph-catenary system. M. Simarro et al. (M. Simarro, S. Postigo, JA Cabrera, et al. A procedure for validating rigid catenary models using evolutionary techniques[J]. Computers&Structures, 2020, 228:106145) proposed a method to verify the validity of the finite element model of the rigid catenary through modal testing. X. Feng et al. (X. Feng, S. Gao, Y. Song, et al. Static and dynamic analysis of conductor rail with large cross-sectional moment of inertia inrigid catenary systems[J]. Energies, 2023, 16(4): 1810) studied the service performance of six new types of large inertia moment buses in high-speed rigid catenary systems.

[0004] However, in previous studies, the stiffness of the suspension device is generally considered as a constant and is mostly selected based on engineering experience, which is inaccurate, while the damping characteristics of the suspension device are basically not considered. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a damping test identification method for a rigid contact network suspension device.

[0006] The present invention provides a damping test identification method for a rigid contact network suspension device, comprising the following steps: An impact hammer is used to input impact excitation into the rigid overhead wire suspension device, and a laser displacement sensor is used to record the vibration displacement time history curve of the suspension device. The damping ratio of the suspension device is calculated using the following formula: ; , In the formula, is the i-th peak value of the vibration displacement time history curve, is the number of peaks in the vibration displacement time history curve; The fast Fourier transform method is used to extract the spectrum of the vibration displacement time history curve of the suspension device, and the first-order vibration main frequency of the suspension device is extracted, which is defined as the natural frequency f of the suspension device. d ; Calculate the damping coefficient c of the suspension: , ; Among them, m is the equivalent mass of the suspension device, and k is the equivalent stiffness of the suspension device.

[0007] The equivalent stiffness k of the suspension device is calculated through simulation or measured through experiments.

[0008] The present invention also provides a specific method for measuring the equivalent stiffness k of the suspension device through an experiment, comprising: A nominal mass block is used to apply a vertical downward load to the suspension device, and the displacement of the suspension device is measured; The ratio of the applied load to the displacement is determined as the equivalent stiffness of the suspension.

[0009] Compared with the prior art, the method of the present invention has at least the following beneficial effects: The present invention calculates and determines the damping and mass of the rigid contact network suspension device by combining the test with the free vibration attenuation method. Compared with the prior art, the obtained values ​​are more accurate. The present invention obtains the equivalent stiffness of the suspension device through an experimental method, which is more accurate than empirical values ​​and values ​​obtained by simulation calculation, and provides effective theoretical support for the research field of rigid contact network structural characteristics. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments of the present invention or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0011] Figure 1 is a schematic diagram of a flow chart of measuring the equivalent stiffness of a suspension device through an experiment according to an embodiment of the present invention; Figure 2 The equivalent stiffness measurement test results of the suspension device obtained in the embodiment of the present invention; Figure 3 It is a schematic flow chart of a damping test identification method for a rigid overhead wire suspension device according to an embodiment of the present invention; Figure 4 is a vibration displacement time history curve of the suspension device in the damping test obtained in the embodiment of the present invention; Figure 5 It is the frequency component of the vibration displacement time history curve of the suspension device in the damping test obtained in the embodiment of the present invention. DETAILED DESCRIPTION

[0012] The following description provides many different embodiments or examples for implementing different features of the present invention. The components and arrangements described in the following specific examples are only used to simplify the present invention and are only used as examples, not to limit the present invention.

[0013] This embodiment provides a test method for measuring the equivalent stiffness of the suspension device. The specific method is as follows: Figure 1 As shown: A non-contact laser signal sensor for measuring the vibration displacement time history curve of the rigid contact network suspension device is installed, a vertical downward load is applied to the rigid contact network suspension device, and the vibration displacement time history curve of the suspension device is extracted and analyzed to identify the equivalent stiffness of the rigid contact network suspension device; A laser displacement sensor is arranged at the rigid contact network suspension device to monitor the vertical displacement of the suspension device. The laser sensor is mounted on an adjustable bracket, and the position and angle of the laser displacement sensor can be adjusted by adjusting the position and angle of the adjustable bracket. Those skilled in the art can understand that any form of adjustable bracket can be used as long as it can adjust the position and angle of the laser displacement sensor to accurately measure the vertical position of the suspension device.

[0014] Adjust the position of the laser displacement sensor so that the laser beam emitted by the laser displacement sensor is accurately pointed to the center of the lower surface of the rigid contact network suspension device to avoid the test data measurement error caused by the swing of the suspension device itself. A nominal mass block is used to apply a vertical downward load to the suspension device, and the displacement of the suspension device is measured by the laser displacement sensor.

[0015] The equivalent stiffness of the suspension device is determined based on the ratio of the applied load to the displacement.

[0016] As a preferred embodiment, in order to measure a more accurate equivalent stiffness value of the suspension device, the load applied to the suspension device is loaded and unloaded multiple times, thereby fitting and obtaining the equivalent stiffness of the suspension device.

[0017] Specifically, the nominal mass blocks are added sequentially, and after each addition of the mass blocks, the laser sensor reading is recorded after the suspension device is stationary. Subsequently, the mass blocks are removed sequentially, and the laser sensor reading is recorded after the suspension device is stationary.

[0018] Preferably, the sum of the masses of all the nominal mass blocks is greater than the force that the suspension device needs to withstand in actual circumstances. That is to say, the range of loads applied in the test is preferably able to cover the range of forces that the suspension device needs to withstand in actual circumstances, so as to obtain a more accurate equivalent stiffness value.

[0019] In this embodiment, the number of nominal blocks is 25, that is, the nominal mass blocks are increased 25 times in sequence, and the nominal mass blocks are decreased 25 times in sequence, and a total of 50 numerical points are obtained as follows: Figure 2 As shown in the figure, the equivalent stiffness of the suspension device is 57720 N / m obtained by linear function fitting.

[0020] In this embodiment, the equivalent stiffness k of the suspension device is obtained by an experimental method, which is more accurate than the empirical value and the value obtained by simulation calculation.

[0021] Another embodiment of the present invention provides a rigid overhead wire suspension device damping test identification method, such as Figure 3 As shown, a laser displacement sensor is arranged at the rigid contact network suspension device to monitor the vertical displacement of the suspension device. The arrangement method is the same as that of the previous embodiment, except that the range of the laser displacement sensor used in this embodiment can be smaller than the range of the laser displacement sensor used in the previous embodiment. This is because the impact excitation applied in this embodiment is generally smaller than the maximum vertical load applied in the previous embodiment, so the vertical displacement of the suspension device in this embodiment is smaller than the vertical displacement of the suspension device in the previous embodiment. The use of a laser displacement sensor with a smaller range can improve the accuracy of the test measurement.

[0022] An impact hammer is used to input impact excitation to the rigid contact network suspension device, and a laser displacement sensor is used to record the vibration displacement time history curve of the suspension device; the displacement time history curve of the suspension device in this embodiment is as follows: Figure 4 As shown; The damping ratio of the suspension device is calculated by the vibration displacement time history curve. and the natural frequency f d ; In this embodiment, the suspension device is regarded as a single degree of freedom system, and the damping ratio of the suspension device is calculated using the free vibration attenuation method: , in, is the damping ratio, is the i-th peak value of the vibration displacement time history curve, is the number of peaks in the vibration displacement time history curve.

[0023] As a preferred method, for the obtained vibration displacement time history curve, extract the upper envelope, and obtain the peak value of the vibration displacement time history curve by calculating the intersection of the envelope and the original vibration displacement signal. Of course, in order to increase the speed of calculation, the first peak can be directly extracted and the last peak Substitute the above formula to calculate the damping ratio.

[0024] The fast Fourier transform method is used to extract the spectrum of the vibration displacement time history curve of the suspension device, and the first-order vibration main frequency of the suspension device is extracted, which is defined as the natural frequency f of the suspension device. d ;like Figure 5 As shown, the natural frequency f of the suspension device in this embodiment is obtained d It is worth noting that the method of extracting the spectrum of the time history curve using the fast Fourier method to obtain the natural frequency is a prior art and will not be described in detail in this application.

[0025] In this embodiment, considering the numerical calculation error, the method of applying impact excitation multiple times is adopted, and the average value of the damping ratio obtained under multiple impact excitations is used as the damping ratio of the suspension device: , in, is the number of trials, and Represent the first peak and the last peak of the vibration displacement time history curve in each test, is the number of peak values ​​of the vibration displacement time history curve of each test. In this embodiment, a total of 4 impact excitations are applied, and the damping ratio of the suspension device is calculated to be 0.00616.

[0026] Finally, calculate the damping coefficient c of the suspension: , ; Wherein, m is the equivalent mass of the suspension device, and k is the equivalent stiffness of the suspension device. The equivalent stiffness can be measured by the test method as in the aforementioned embodiment, or can be obtained by other methods, such as simulation calculation.

[0027] In this embodiment, the equivalent stiffness measured in the above-mentioned embodiment is used to calculate the equivalent mass of the suspension device to be 6.7568 kg and the damping coefficient to be 7.6939 Ns / m.

[0028] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A damping test identification method for a rigid overhead wire suspension device, characterized in that: The following steps are involved: An impact hammer is used to input impact excitation into the rigid overhead wire suspension device, and the vibration displacement time history curve of the suspension device is recorded; The damping ratio of the suspension device is calculated using the following formula: ; ， in, is the i-th peak value of the vibration displacement time history curve, is the number of peaks in the vibration displacement time history curve; The fast Fourier transform method is used to extract the spectrum of the vibration displacement time history curve of the suspension device, and the first-order vibration main frequency of the suspension device is extracted, which is defined as the natural frequency f of the suspension device. d ; Calculate the damping coefficient c of the suspension: ， ； Among them, m is the equivalent mass of the suspension device, and k is the equivalent stiffness of the suspension device.

2. A damping test identification method for a rigid contact network suspension device according to claim 1, characterized in that: The damping ratio of the suspension device The damping ratio obtained by applying the impact excitation multiple times is averaged.

3. A damping test identification method for a rigid contact network suspension device according to claim 2, characterized in that: The equivalent stiffness k of the suspension device is calculated through simulation or measured through experiments.

4. A damping test identification method for a rigid contact network suspension device according to claim 3, characterized in that: The specific methods for measuring the equivalent stiffness k of the suspension device through experiments include: A nominal mass block is used to apply a vertical downward load to the suspension device, and the displacement of the suspension device is measured; The ratio of the applied load to the displacement is determined as the equivalent stiffness of the suspension.

5. A damping test identification method for a rigid overhead wire suspension device according to claim 4, characterized in that: The load applied to the suspension device by multiple loading and unloading is fitted to obtain the equivalent stiffness of the suspension device.

6. A damping test identification method for a rigid contact network suspension device according to claim 5, characterized in that: The nominal mass blocks are added in sequence. After each addition of the mass blocks, the displacement of the suspension device is recorded after the suspension device comes to rest. Subsequently, the mass blocks are removed in sequence. Similarly, the displacement of the suspension device is recorded after the suspension device comes to rest.

7. A damping test identification method for a rigid contact network suspension device according to claim 6, characterized in that: The sum of the masses of all the nominal mass blocks is greater than the force that the suspension device needs to withstand in actual situations.

8. A damping test identification method for a rigid contact network suspension device according to any one of claims 1 to 7, characterized in that: A laser displacement sensor is arranged at the rigid contact network suspension device to detect the vertical displacement of the suspension device.

9. A damping test identification method for a rigid overhead wire suspension device according to claim 8, characterized in that: The laser displacement sensor is mounted on an adjustable bracket, and the position of the laser displacement sensor is adjusted by adjusting the bracket so that the laser beam of the laser displacement sensor accurately points to the center position of the lower surface of the suspension device.

10. A damping test identification method for a rigid overhead wire suspension device according to claim 9, characterized in that: The range of the laser displacement sensor used in the test to measure the equivalent stiffness k of the suspension device is greater than the range of the laser displacement sensor used in the impact excitation test.

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