A MTMD vibration reduction system and its control method for turnout frog area under complex load conditions

Abstract

A MTMD vibration reduction system and its control method for turnout frog area under complex load conditions, including: S1. Establish a finite element model of the turnout frog area, and obtain the modal information of the frog structure through modal analysis; S2. Determine the modal orders and frequencies to be controlled according to the modal information of the turnout frog structure model; S3. Determine the modal shapes of each order and the installation positions of each sub-TMD according to the modal characteristics of the finite element model of the turnout frog area; S4. Develop different design schemes according to the extended fixed-point theory and multi-modal control design method, and calculate the parameters and quantities of each sub-TMD; S5. Combine the sub-TMD parameters in the MTMD system calculated by each scheme, establish a finite element model of the MTMD for the turnout frog area, compare the differences in the vibration acceleration responses at the frog center positions of each MTMD system, and select the optimal sub-TMD parameters and quantities. The present invention applies the MTMD technology to the turnout frog area, effectively controls the vibration response of the turnout frog area, improves the vibration reduction effect of the turnout frog area, and meets the environmental vibration requirements of the turnout frog area.

Description

Technical Field

[0001] The present invention relates to a MTMD vibration reduction system and its control method for turnout frog area under complex load conditions, belonging to the technical field of turnout vibration reduction in rail transit. Background Art

[0002] As an important part of the rail transit line, the turnout has a complex structure and bears the impact load and vibration generated when the train passes. Especially in the turnout frog area, the repeated action of the load will generate complex vibrations, which will not only accelerate the wear of turnout components and cause structural fatigue, but may also lead to changes in the track geometry, thereby affecting the running stability and safety of the train. In addition, long-term vibration may also damage the infrastructure such as buildings and underground pipelines around the turnout area, affecting the harmony of the urban environment and the normal life of residents. Therefore, effectively suppressing the vibration in the turnout frog area is crucial for ensuring the safety of rail transit and extending the service life of the line.

[0003] The turnout frog area bears the combined action of train dynamic load, temperature load, etc. These loads have randomness, pulsatility and high-frequency characteristics, resulting in complex vibration forms. The structural space in the turnout frog area is limited, and it is difficult to install large vibration reduction devices. The tuned mass damper (TMD) has a simple structure and consists of an additional mass block, a spring and a damper, etc. It belongs to a passive vibration absorber and is an effective structural vibration control device.

[0004] At present, the TMD generally can only control the vibration of a structure at one frequency. If there are multiple main vibration frequencies in the structure, the number and mass of the TMD need to be increased. However, this will have a certain impact on the dynamic characteristics of the structure and increase the control cost.

[0005] Therefore, when regulating a structure with multiple main vibration frequencies, the existing TMD has limitations, resulting in the inability to ensure the optimal vibration reduction effect when the TMD is applied to the turnout frog area.

[0006] MTMD (Multiple Tuned Mass Dampers) is a multiple tuned mass damper, which is composed of n TMDs. The number of n is determined according to needs, and the n TMDs are all sub-TMDs of the MTMD. Summary of the Invention

[0007] The purpose of the present invention is to solve the limitation problem of the TMD when regulating the turnout frog area under complex load conditions with multiple main vibration frequencies, and to propose a MTMD vibration reduction system and its control method for the turnout frog area under complex load conditions.

[0008] The technical solution realized by the present invention is as follows. A control method for a MTMD vibration reduction system in the turnout frog area under complex load conditions comprises the following steps:

[0009] S1. Establish a finite element model of the turnout frog area, and obtain the modal information of the frog structure through modal analysis, including modal frequencies, modal vibration modes, etc.

[0010] S2. Determine the modal orders and frequencies to be controlled according to the modal information of the finite element model of the turnout frog area and harmonic response analysis.

[0011] S3. Determine the modal vibration modes of each order according to the modal characteristics of the finite element model of the turnout frog area, and determine the installation positions of each sub-TMD.

[0012] S4. According to the extended fixed-point theory and multi-modal control design method, formulate different design schemes, design the parameters and quantities of each sub-TMD; according to the mass ratios of different schemes, set different grouping situations, calculate corresponding parameters such as frequency ratios and damping ratios, and design the corresponding MTMD system.

[0013] S5. Use the parameters of the sub-TMDs in the designed different MTMD systems to establish an MTMD finite element model of the turnout frog area, compare the differences in the vibration acceleration responses at the frog center positions of each MTMD system, and select the optimal parameters and quantities of the sub-TMDs.

[0014] The different design schemes include the following two:

[0015] The first scheme is to set different sub-TMD structural parameters. A single sub-TMD structure is only responsible for tuning one frequency, and the number of tuned frequencies is controlled by adjusting the number of installed sub-TMDs.

[0016] The calculation expressions of the TMD parameters involved in the first scheme include:

[0017] The mass ratio of the tuned mass damper TMD:

[0018] The frequency ratio of the tuned mass damper TMD:

[0019] The damping ratio of the tuned mass damper TMD:

[0020] In the above formulas, μ is the mass ratio of the TMD to the main structure; m T is the mass of the TMD mass block; M 主 is the mass of the main structure; λ is the frequency ratio of the TMD to the main structure; ξ opt is the optimal damping ratio of the TMD to the main structure;

[0021] The second scheme is to set the same sub-TMD structural parameters. A single sub-TMD structure is responsible for tuning multiple frequencies, and the number of tuned frequencies is tuned through the optimization control of the sub-TMD structure itself.

[0022] The calculation expressions of the TMD parameters involved in the second solution include:

[0023] The mass ratio of the i-th order modal tuned mass damper TMD:

[0024] The frequency ratio of the i-th order modal tuned mass damper TMD:

[0025]

[0026] The damping ratio of the i-th order modal tuned mass damper TMD:

[0027]

[0028] In the above formula, μ i is the mass ratio of the i-th order modal TMD to the main structure; m i is the mass of the mass block of the i-th order modal TMD; M 主 is the mass of the main structure; λ i is the frequency ratio of the i-th order modal TMD to the main structure; ξ opti is the optimal damping ratio of the i-th order modal TMD to the main structure.

[0029] The installation positions of the respective sub-TMDs are selected to be set at the locations where the modal vibration mode displacement is the largest.

[0030] According to the mass ratios of the first solution and the second solution, different grouping situations are set, and the corresponding frequency ratios, damping ratios and other parameters are calculated to design the corresponding MTMD system.

[0031] According to the designed MTMD system, a corresponding finite element model of the MTMD for the turnout frog area is established; the process and load conditions of the train traveling in the turnout frog area are simulated, different working conditions are set, and the vibration responses under different solutions are compared and analyzed; the MTMD system with the smallest vibration acceleration value at the frog center position is selected, and the corresponding sub-TMD parameters are used as the optimal parameters to reduce the vibration of the turnout frog area.

[0032] An MTMD vibration reduction system for a turnout frog area under complex load conditions according to the present invention is composed of a turnout frog area and an MTMD system. The turnout frog area serves as the main structure that needs vibration reduction, and the MTMD system serves as a vibration reduction structure attached to the turnout frog area and is connected to the main structure through springs and dampers, and the two together form a vibration reduction system; the MTMD system is composed of a number of sub-TMDs, and the sub-TMDs include dampers, springs and mass blocks; the dampers and springs are vertically installed on the mass blocks, and the dampers are located between the two springs.

[0033] The beneficial effects of the present invention are as follows. The present invention overcomes the deficiencies of traditional vibration damping devices in the turnout frog area, such as limited vibration damping effect and poor reliability. It innovatively applies the MTMD technology to the turnout frog area, which can effectively reduce the vibration response in the turnout frog area, effectively improve the vibration damping effect in the turnout frog area, and meet the environmental vibration requirements in the turnout frog area. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a flowchart of the control method for the MTMD vibration damping system in the turnout frog area under complex load conditions of the present invention;

[0035] Figure 2 It is a schematic plan view of the turnout frog area;

[0036] Figure 3 It is a finite element model diagram of the turnout frog area;

[0037] Figure 4 It is a schematic diagram of the vibration acceleration at the frog center position of the MTMD system designed in the first scheme of the embodiment of the present invention;

[0038] Figure 5 It is a schematic diagram of the vibration acceleration at the frog center position of the MTMD system designed in the second scheme of the embodiment of the present invention;

[0039] Figure 6 It is a schematic diagram of the MTMD structure; in the figure, 1 is the mass block; 2 is the spring; 3 is the damper. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0040] As Figure 1 shown, a control method for the MTMD vibration damping system in the turnout frog area under complex load conditions in this embodiment includes the following steps:

[0041] S1. Use finite element analysis software to establish a finite element solid model of the turnout frog area, set the material parameters and analysis frequency range of the turnout, etc., conduct modal analysis on the structure of the turnout frog area, and obtain the modal frequencies, modal vibration modes, etc. of the structure of the turnout frog area through modal analysis.

[0042] S2. According to the vibration main frequency and vibration mode of the finite element solid model of the turnout frog area, and conduct harmonic response analysis on the turnout structure using finite element software, it is obtained that the vibration acceleration admittance of the first n-order vibrations of the structure is relatively high, and then the first n-order modes and the corresponding vibration main frequencies of the turnout structure are determined.

[0043] S3. Based on the modal analysis results of the finite element solid model of the turnout frog area, determine the n-order modal vibration modes, and determine the installation positions of each sub-TMD at the places with the maximum modal vibration displacement.

[0044] S4. Set parameters according to the extended fixed-point theory, the multi-modal control design method, and two schemes. The first scheme is to set different sub-TMD structural parameters. A single sub-TMD structure is only responsible for tuning one frequency, and the number of tuned frequencies is controlled by adjusting the number of installed sub-TMDs. The second scheme is to set the same sub-TMD structural parameters. Each sub-TMD structure is responsible for tuning multiple frequencies, and the number of tuned frequencies is controlled by optimizing the structure of the sub-TMD structure itself.

[0045] The parameter calculation expressions described in the first scheme include the following forms:

[0046] Mass ratio of the tuned mass damper (TMD):

[0047] Frequency ratio of the tuned mass damper (TMD):

[0048] Damping ratio of the tuned mass damper (TMD):

[0049] In the formula, μ is the mass ratio of the TMD to the main structure; m T is the mass of the TMD mass block; M 主 is the mass of the main structure; λ is the frequency ratio of the TMD to the main structure; ξ opt is the optimal damping ratio of the TMD to the main structure.

[0050] The parameter calculation expressions described in the second scheme include the following forms:

[0051] Mass ratio of the i-th order modal tuned mass damper (TMD):

[0052] Frequency ratio of the i-th order modal tuned mass damper (TMD):

[0053]

[0054] Damping ratio of the i-th order modal tuned mass damper (TMD):

[0055]

[0056] In the formula, μ i is the mass ratio of the i-th order modal TMD to the main structure; m i is the mass of the i-th order modal TMD mass block; M 主 is the mass of the main structure; λ i is the frequency ratio of the i-th order modal TMD to the main structure; ξ opti is the optimal damping ratio of the i-th order modal TMD to the main structure.

[0057] Modify the mass ratios of the sub-TMDs in the two schemes, calculate the corresponding frequency ratios and damping ratios for different mass ratios, design the parameters of each sub-TMD, and establish different control groups.

[0058] S5. Establish a finite element model of the MTMD in the turnout frog area and use the parameters of the sub-TMDs in different MTMD systems designed based on Step S4.

[0059] In the first scheme, n sub-TMDs are designed for the nth-order mode and the main vibration frequency respectively, with different parameters for each sub-TMD. The sub-TMDs are established in the finite element solid model, the parameters of each sub-TMD are input, and the simulation is carried out to simulate the train traveling process and load conditions in the turnout frog area, and the vibration acceleration response results at the frog center position are obtained.

[0060] In the second scheme, sub-TMDs are designed for the nth-order mode and the main vibration frequency. Spring-damper-mass elements are applied to the finite element solid model of the turnout, and the parameters are assigned according to the calculated values. The mass, stiffness, and damping of each sub-TMD are the ratios of the total mass, total stiffness, and total damping values to the number of dampers. The simulation is carried out to simulate the train traveling process and load conditions in the turnout frog area, and the vibration acceleration response results at the frog center position are obtained.

[0061] Both the first scheme and the second scheme modify the mass ratio, frequency ratio, and damping ratio of the sub-TMD. Each scheme forms multiple groups of situations. By comparing and analyzing the vibration displacement frequency response results, the optimal parameters in each of the two schemes and the better scheme among the two schemes are obtained.

[0062] The modal analysis described in this embodiment is a method for studying the dynamic characteristics of structures, generally applied in the field of engineering vibration. Among them, the mode refers to the inherent vibration characteristics of the main structure, and each mode has specific natural frequency, damping ratio, and modal shape. The process of analyzing these modal parameters is called modal analysis. The modal analysis in this embodiment is carried out in finite element software. First, a model is established in the software, and then the software can directly complete the modal analysis and output relevant modal information.

[0063] The modal frequency in this embodiment refers to the general natural frequency. Usually in structural design, it is necessary to avoid the natural frequency from the excitation frequency to prevent resonance. The modal shape in this embodiment refers to the displacement distribution in each free vibration mode (i.e., mode) when the structure system is excited and vibrates. Each mode shape represents the vibration morphology of the structure at a specific frequency.

[0064] Figure 2 It is a schematic plan view of the turnout frog area. According to the frog structure, a finite element model of the turnout frog area is established as Figure 3 shown.

[0065] The vibration acceleration response results at the frog center position obtained by simulating the train traveling process and load conditions in the turnout frog area are asFigure 4 , Figure 5 as shown. From Figure 4 it can be seen that under the optimal parameter conditions of the MTMD designed in the first scheme, the MTMD vibration reduction method obtained by the present invention has a remarkable effect on the vibration reduction of the turnout frog area structure. Figure 4 It is the vibration acceleration response result of the frog position obtained by calculating and simulating the MTMD finite element model of the turnout frog area established by the method of the present invention with the optimal mass ratio, frequency ratio, and damping ratio under the traveling process and load conditions of the train in the turnout frog area. It can only be reflected from the calculation results that under the optimal mass ratio, frequency ratio, and damping ratio parameters of the MTMD, the effect of the first scheme.

[0066] From Figure 5 it can be seen that under the optimal parameter conditions of the MTMD designed in the second scheme, the MTMD vibration reduction method obtained by the present invention has a remarkable effect on the vibration reduction of the turnout frog area structure. Figure 5 It is the vibration acceleration response result of the frog position obtained by calculating and simulating the MTMD finite element model of the turnout frog area established by the method of the present invention with the optimal mass ratio, frequency ratio, and damping ratio under the traveling process and load conditions of the train in the turnout frog area. It can only be reflected from the calculation results that under the optimal mass ratio, frequency ratio, and damping ratio parameters of the MTMD, the effect of the second scheme.

[0067] As Figure 6 shown, the MTMD vibration reduction system for the turnout frog area under complex load conditions in this embodiment is composed of a turnout frog area and an MTMD system. The turnout frog area is the main structure that needs vibration reduction, and the MTMD system is an additional vibration reduction structure attached to the turnout frog area and is connected to the main structure through springs and dampers, and the two together form a vibration reduction system; the MTMD system is composed of several sub-TMDs, and the sub-TMDs include dampers 3, springs 2, and mass blocks 1; the dampers 3 and springs 2 are vertically installed on the mass blocks 1, and the dampers 3 are located between the two springs 2.

Claims

1. A control method for a MTMD vibration reduction system in a turnout frog area under complex load conditions, characterized in that: The method steps are as follows: S1. Establish a finite element model of the turnout frog area and obtain the modal information of the frog structure, including frequency and vibration mode, through modal analysis; S2. Determine the modal order and frequency to be controlled based on the modal information and harmonic response analysis of the finite element model of the turnout frog area; S3. Determine the modal vibration shapes of each order and the installation positions of each sub-TMD according to the modal characteristics of the finite element model of the turnout frog area; S4. According to the extended fixed-point theory and multi-modal control design method, formulate different design schemes, design the parameters and quantity of each sub-TMD; according to the mass ratio of different schemes, set different grouping situations, calculate the corresponding frequency ratio and damping ratio parameters, and design the corresponding MTMD system; S5. Use the designed sub-TMD parameters of different MTMD systems to establish the MTMD finite element model of the turnout frog area, compare the differences in the vibration acceleration response of the switch center position of each MTMD system, and select the optimal sub-TMD parameters and quantity.

2. The control method of the MTMD vibration reduction system in the turnout frog area under complex load conditions according to claim 1 is characterized in that: The different design solutions include the following two: The first solution is to set different sub-TMD structure parameters. A single sub-TMD structure is responsible for tuning only one frequency. The number of tuned frequencies can be controlled by adjusting the number of sub-TMDs installed. The calculation expressions of the TMD parameters involved in the first solution include: Mass ratio of tuned mass damper TMD: Frequency ratio of tuned mass damper TMD: Damping ratio of tuned mass damper TMD: In the above formula, μ is the mass ratio of TMD to the main structure; m T is the mass of the TMD mass block; M 主 The mass of the main structure; λ is the frequency ratio of TMD to the main structure; ξ opt is the optimal damping ratio between TMD and main structure; The second solution is to set the same sub-TMD structure parameters, and a single sub-TMD structure is responsible for tuning multiple frequencies, and the number of frequencies is tuned through the optimization control of the sub-TMD structure itself; The calculation expressions of the TMD parameters involved in the second solution include: Mass ratio of the tuned mass damper TMD of the i-th mode: Frequency ratio of the i-th mode tuned mass damper TMD: The damping ratio of the tuned mass damper TMD for the i-th mode is: In the above formula, μ i is the mass ratio of the i-th mode TMD to the main structure; m i is the mass of the TMD mass block of the i-th mode; M 主 is the mass of the main structure; i is the ratio of the i-th mode TMD to the main structure frequency; ξ opti is the optimal damping ratio of the i-th mode TMD to the main structure.

3. The control method of the MTMD vibration reduction system in the turnout frog area under complex load conditions according to claim 1 is characterized in that: The installation position of each sub-TMD is selected to be set at the location where the modal vibration type displacement is maximum.

4. The control method of the MTMD vibration reduction system in the turnout frog area under complex load conditions according to claim 2 is characterized in that: According to the mass ratio between the first scheme and the second scheme, different grouping situations are set, the corresponding frequency ratio and damping ratio parameters are calculated, and the corresponding MTMD system is designed.

5. The control method of the MTMD vibration reduction system in the turnout frog area under complex load conditions according to claim 1 is characterized in that: According to the designed MTMD system, a finite element model of the corresponding MTMD in the turnout frog area is established; the train travel process and load conditions in the turnout frog area are simulated, different working conditions are set, and the vibration responses under different schemes are compared and analyzed; the MTMD system with the smallest vibration acceleration value at the switch center position is selected, and the corresponding sub-TMD parameters are used as the optimal parameters to reduce the vibration of the turnout frog area.

6. A switch frog area MTMD vibration reduction system that implements the control method of the switch frog area MTMD vibration reduction system under complex load conditions as described in any one of claims 1 to 5, characterized in that: The switch frog area MTMD vibration reduction system is composed of a switch frog area and an MTMD system; the switch frog area is the main structure that needs vibration reduction, and the MTMD system is a vibration reduction structure attached to the switch frog area and connected to the main structure through spring damping, and the two together constitute a vibration reduction system; the MTMD system is composed of a plurality of sub-TMDs, and the sub-TMDs include a damper, a spring and a mass block; the damper and the spring are vertically installed on the mass block, and the damper is located between two springs.

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