A rigid catenary suspension device damping test identification method

Abstract

The present application is suitable for the field of rigid contact net spare parts test, and provides a damping test identification method for rigid contact net suspension device, which comprises the following steps: installing a non-contact laser signal sensor for measuring the time history curve of the vibration displacement of the rigid contact net suspension device; applying a vertical downward load to the rigid contact net suspension device; extracting and analyzing the time history curve of the vibration displacement of the suspension device to identify the rigidity of the rigid contact net suspension device; inputting an impact excitation to the rigid contact net suspension device by using an impact force hammer; extracting and analyzing the time history data of the vibration displacement of the suspension device recorded by the laser displacement sensor; and calculating the damping and mass of the rigid contact net suspension device by using the free vibration decay method. The present application provides a damping test identification method for rigid contact net suspension device, which determines the damping and mass of the rigid contact net suspension device by combining the test with the free vibration decay method, and can provide effective support for the structure characteristic research of the rigid contact net.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of rigid catenary component testing, and particularly relates to a damping test identification method for a rigid catenary suspension device. BACKGROUND

[0002] In the mountainous tunnel railway and urban rail transit tunnel line in the Midwest, the rigid catenary is an important way for the train to obtain continuous and stable power, and its dynamic interaction with the pantograph directly affects the current collection performance of the train. At present, the running speed of the domestic rigid catenary line is below 160 km / h, and the existing speed grade is difficult to meet the development needs of high-speed and efficient transportation of mountainous railways and urban rail transit. In order to improve the reliability of the rigid catenary in service under high-speed conditions, it is necessary to conduct more in-depth research on the structural characteristics of its components. The present application accurately identifies the damping and mass of the rigid catenary suspension device by carrying out field tests on the rigid catenary suspension device, thereby providing theoretical support for the design of high-speed rigid catenary.

[0003] Rigid catenary is an important way for electrified trains in tunnels to obtain electric energy. At present, the research of 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 finite element model of rigid catenary by using absolute nodal coordinate formulation (ANCF), and pointed out that the model can be linearized appropriately to improve the calculation efficiency. In addition, the global contact wire wear considering the wear wavelength and amplitude was introduced, and its influence on the current collection performance of high-speed pantograph-catenary system at a speed of 200 km / h was analyzed. M. Simarro et al. (M. Simarro, S. Postigo, J. A. 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 effectiveness of the finite element model of rigid catenary by modal test. 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 in rigid catenary systems[J]. Energies, 2023, 16(4): 1810) studied the service performance of six new types of large inertia moment busbars in high-speed rigid catenary system.

[0004] However, in previous studies, the stiffness of the suspension device is generally considered as a constant value and is often selected based on engineering experience, which is not accurate, and the damping characteristics of the suspension device are not considered at all. SUMMARY

[0005] To solve the above technical problems, the present application provides a rigid catenary suspension device damping test identification method.

[0006] The application provides a damping test identification method for a rigid catenary suspension device, and comprises the following steps.

[0007] An impact force hammer is used to input an impact excitation to the rigid catenary suspension device, and a laser displacement sensor is used to record a vibration displacement time history curve of the suspension device.

[0008] The damping ratio of the suspension device is calculated by the following formula ;

[0009] ,

[0010] In the formula, is the i th peak value of the vibration displacement time history curve, is the number of peak values of the vibration displacement time history curve.

[0011] The vibration displacement time history curve of the suspension device is subjected to frequency spectrum extraction by using a fast Fourier method, a first-order vibration main frequency of the suspension device is extracted, and the first-order vibration main frequency is defined as the natural frequency f of the suspension device d ;

[0012] The damping coefficient c of the suspension device is calculated as follows

[0013] , ;

[0014] In the formula, m is the equivalent mass of the suspension device, and k is the equivalent stiffness of the suspension device.

[0015] In the formula, the equivalent stiffness k of the suspension device is calculated by simulation or measured by a test.

[0016] The application further provides a specific method for measuring the equivalent stiffness k of the suspension device by a test, comprising the following steps.

[0017] A nominal mass block is used to apply a vertically downward load to the suspension device, and the displacement of the suspension device is measured.

[0018] The ratio of the applied load to the displacement is determined as the equivalent stiffness of the suspension device.

[0019] Compared with the prior art, the method has at least the following beneficial effects:

[0020] The damping and mass of the rigid catenary suspension device are calculated and determined by the method combining the test with the free vibration decay, and the obtained values are more accurate compared with the prior art.

[0021] The equivalent stiffness of the suspension device is obtained by the test method, and the obtained value is more accurate compared with the experience value and the value obtained by simulation, thereby providing effective theoretical support for the structure characteristic research field of the rigid catenary. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments of the present application or the prior art description. Obviously, the drawings described below are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0023] Figure 1 is a flowchart of the equivalent stiffness of the suspension device measured by the test of the embodiments of the present application;

[0024] Figure 2 is the test result of the equivalent stiffness of the suspension device obtained by the embodiments of the present application;

[0025] Figure 3 is a flowchart of a damping test identification method of a rigid catenary suspension device according to the embodiments of the present application;

[0026] Figure 4 is a vibration displacement time history curve of the suspension device in the damping test obtained by the embodiments of the present application;

[0027] Figure 5 is the frequency composition of the vibration displacement time history curve of the suspension device in the damping test obtained by the embodiments of the present application. DETAILED DESCRIPTION

[0028] The following description provides many different embodiments, or examples, for implementing different features of the application. Specific examples are described in following detail to provide a thorough description of embodiments of the application. These examples are not intended to be limiting. They are described to provide a description of one or more embodiments of the application.

[0029] The embodiments provide a test method for measuring the equivalent stiffness of the suspension device, and the specific method is as shown in Figure 1 .

[0030] A non-contact laser signal sensor for measuring the vibration displacement time history curve of the rigid catenary suspension device is installed, a vertical downward load is applied to the rigid catenary 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 catenary suspension device.

[0031] A laser displacement sensor is arranged at the rigid catenary suspension device to monitor the vertical displacement of the suspension device. The laser sensor is installed on an adjustable support, and the pose of the laser displacement sensor can be adjusted by the position and angle of the adjustable support. Those skilled in the art can understand that any form of adjustable support can be used as long as it can adjust the pose of the laser displacement sensor to accurately measure the vertical position of the suspension device.

[0032] The pose of the laser displacement sensor is adjusted so that the laser beam emitted by the laser displacement sensor is accurately directed at the center position of the lower surface of the rigid catenary suspension device to avoid measurement errors of test data caused by swinging of the suspension device itself. A nominal mass block is used to apply a vertically downward load to the suspension device, and the displacement of the suspension device is measured by the laser displacement sensor.

[0033] The equivalent stiffness of the suspension device is determined according to the ratio of the amount of applied load to the amount of displacement.

[0034] 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 increased and decreased by multiple times, so that the equivalent stiffness of the suspension device is fitted.

[0035] Specifically, the nominal mass blocks are sequentially increased, and after each increase in mass block, the laser sensor reading is recorded after the suspension device is stationary. Subsequently, the mass blocks are sequentially removed, and the laser sensor reading is recorded after the suspension device is stationary.

[0036] As a preferred embodiment, the total mass of all the nominal mass blocks is greater than the force that the suspension device needs to bear in actual situations, that is, the range of the load applied in the test is preferably able to cover the range of the force that the suspension device needs to bear in actual situations, so as to obtain a more accurate equivalent stiffness value.

[0037] In this embodiment, the number of nominal blocks is 25, that is, the nominal mass blocks are sequentially increased 25 times, and the nominal mass blocks are sequentially decreased 25 times, and the total of 50 numerical points obtained is as shown in Figure 2 The equivalent stiffness of the suspension device is fitted by a linear function to be 57720 N / m.

[0038] This embodiment obtains the equivalent stiffness k of the suspension device through a test method, which is more accurate than the empirical value and the value obtained by simulation calculation.

[0039] Another embodiment of the present application provides a method for identifying the damping test of a rigid catenary suspension device, as shown in Figure 3 The laser displacement sensor is arranged at the rigid catenary suspension device to monitor the vertical displacement of the suspension device, and 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 that 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 that in the previous embodiment, and the use of a laser displacement sensor with a smaller range can improve the accuracy of the test measurement.

[0040] An impact hammer is used to input an impact excitation into 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;

[0041] The damping ratio of the suspension device is calculated by the vibration displacement time history curve. and the natural frequency f d ;

[0042] 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:

[0043] ,

[0044] 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.

[0045] As a preferred method, for the obtained vibration displacement time history curve, extract its 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.

[0046] The fast Fourier transform method is used to extract the spectrum of the suspension device's vibration displacement time history curve, 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 transform method to obtain the natural frequency is a prior art and will not be described in detail in this application.

[0047] 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:

[0048] ,

[0049] in, is the number of trials, and respectively represent the first peak and the last peak of the vibration displacement time history curve in each test, is the number of peaks of the vibration displacement time history curve in each test. In this embodiment, 4 impact excitations are applied, and the damping ratio of the suspension device is calculated to be 0.00616.

[0050] Finally, the damping coefficient c of the suspension device is calculated:

[0051] , ;

[0052] wherein m is the equivalent mass of the suspension device, and k is the equivalent stiffness of the suspension device, which can be measured by the test method of the foregoing embodiment, or can be obtained by other means, such as simulation calculation.

[0053] In this embodiment, the equivalent stiffness is measured by the method of the foregoing embodiment, and the equivalent mass of the suspension device is calculated to be 6.7568 kg, and the damping coefficient is 7.6939 Ns / m.

[0054] The above merely describes preferred embodiments of the present application and is not intended to limit the present application, and any modification, equivalent replacement, and improvement within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A damping test identification method for a rigid catenary suspension device, characterized in that: The following steps are involved: An impact hammer is used to input impact excitation into the rigid catenary 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 suspension device's vibration displacement time history curve, 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: ， ； Where m is the equivalent mass of the suspension device, k is the equivalent stiffness of the suspension device; The equivalent stiffness k of the suspension device is measured by experiment, and the specific method includes: 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; 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.

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

3. A damping test identification method for a rigid catenary suspension device according to claim 2, characterized in that: The load applied to the suspension device is loaded and unloaded multiple times, and the equivalent stiffness of the suspension device is obtained by fitting.

4. A damping test identification method for a rigid catenary suspension device according to claim 3, characterized in that: The nominal mass blocks are added in sequence. After each addition of the mass blocks, the suspension device is kept stationary and the displacement of the suspension device is recorded. Subsequently, the mass blocks are removed in sequence. Similarly, the suspension device is kept stationary and the displacement of the suspension device is recorded.

5. A damping test identification method for a rigid catenary suspension device according to any one of claims 1 to 4, 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.

6. A damping test identification method for a rigid catenary suspension device according to claim 5, 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.

7. A damping test identification method for a rigid catenary suspension device according to claim 6, 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.

Images