Turnout frog area MTMD vibration reduction system under complex load condition and control method of turnout frog area MTMD vibration reduction system

Abstract

The invention discloses a turnout frog area MTMD damping system under a complex load condition and a control method thereof, and the method comprises the steps: S1, building a finite element model of a turnout frog area, and obtaining the modal information of a frog structure through modal analysis; s2, according to the modal information of the turnout frog structure model, determining modal order and frequency needing to be controlled; s3, according to the modal characteristics of the finite element model of the turnout frog area, determining the modal shape of each order and the mounting position of each sub TMD; s4, formulating different design schemes according to an extended fixed-point theory and a multi-modal control design method, and calculating parameters and quantity of each sub-TMD; and S5, establishing a turnout frog area MTMD finite element model in combination with the sub-TMD parameters in the MTMD system calculated by each scheme, comparing the vibration acceleration response difference of the frog center position of each MTMD system, and selecting the optimal sub-TMD parameters and number. The MTMD technology is applied to the turnout frog area, the vibration response of the turnout frog area is effectively controlled, the vibration reduction effect of the turnout frog area is improved, and the environment vibration requirement of the turnout frog area is met.

Description

Technical Field

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

[0002] As an important part of rail transit lines, turnouts have complex structures and are subject to impact loads and vibrations generated by trains passing through. In particular, the repeated action of loads in the turnout frog area will produce complex vibrations, which will not only lead to accelerated wear of turnout components and structural fatigue, but may also cause changes in the track geometry, thereby affecting the running stability and safety of the train. In addition, long-term vibrations may also damage infrastructure such as buildings and underground pipelines around the turnout area, affecting the harmony of the urban environment and the normal lives of residents. Therefore, effectively suppressing the vibration of the turnout frog area is crucial to ensuring rail transit safety and extending the life of the line.

[0003] The turnout frog area is subjected to the combined effects of train dynamic loads and temperature loads. These loads are random, pulsed and high-frequency, resulting in complex vibration forms. The structural space of 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, consisting of an additional mass block, springs and damping. It is a passive vibration absorber and an effective structural vibration control device.

[0004] At present, TMD can generally only control the vibration of one frequency of the structure. If the structure has multiple main vibration frequencies, the number and quality of TMDs 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, the existing TMD has limitations when regulating structures with multiple main vibration frequencies, 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 n is determined according to needs, and the n TMDs are all sub-TMDs of MTMD. Summary of the invention

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

[0008] The technical solution implemented by the present invention is as follows: a control method for the MTMD vibration reduction system in the turnout frog area under complex load conditions, the steps are as follows:

[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 frequency, modal vibration shape, etc.

[0010] S2. Determine the modal order and frequency that need to be controlled based on the modal information and harmonic response analysis of the finite element model of the turnout frog area.

[0011] S3. According to the modal characteristics of the finite element model of the turnout frog area, the modal vibration shapes of each order are determined, and the installation positions of each sub-TMD are determined.

[0012] S4. According to the extended fixed-point theory and multi-modal control design method, different design schemes are formulated, and the parameters and quantity of each sub-TMD are designed. According to the mass ratio of different schemes, different grouping situations are set, the corresponding frequency ratio, damping ratio and other parameters are calculated, and the corresponding MTMD system is designed.

[0013] 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.

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

[0015] 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.

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

[0017] Mass ratio of tuned mass damper TMD:

[0018] Frequency ratio of tuned mass damper TMD:

[0019] Damping ratio of tuned mass damper TMD:

[0020] 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;

[0021] 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;

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

[0023] Mass ratio of the tuned mass damper TMD of the i-th mode:

[0024] Frequency ratio of the i-th mode tuned mass damper TMD:

[0025]

[0026] The damping ratio of the tuned mass damper TMD for the i-th mode is:

[0027]

[0028] 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 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.

[0029] The installation position of each sub-TMD is selected to be set at the location where the modal vibration type displacement is maximum.

[0030] According to the mass ratio between the first scheme and the second scheme, different grouping situations are set, the corresponding frequency ratio, damping ratio and other parameters are calculated, and the corresponding MTMD system is designed.

[0031] 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.

[0032] The present invention discloses a MTMD vibration reduction system for a turnout frog area under complex load conditions, which is composed of a turnout frog area and an MTMD system. The turnout frog area is a main structure that needs vibration reduction, and the MTMD system is a vibration reduction structure attached to the turnout 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.

[0033] The beneficial effect of the present invention is that the present invention overcomes the shortcomings of limited vibration reduction effect and poor reliability of traditional vibration reduction devices in the turnout frog area, and innovatively adopts MTMD technology to be applied to the turnout frog area, which can effectively reduce the vibration response of the turnout frog area, effectively improve the vibration reduction effect of the turnout frog area, and adapt to the environmental vibration requirements of the turnout frog area. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

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

[0037] Figure 4 A schematic diagram of vibration acceleration of the fork center position of the MTMD system is designed for the first solution of the embodiment of the present invention;

[0038] Figure 5 A schematic diagram of vibration acceleration of the fork center position of the MTMD system is designed for the second solution of the embodiment of the present invention;

[0039] Figure 6 Schematic diagram of MTMD structure; in the figure, 1 is the mass block; 2 is the spring; 3 is the damper. DETAILED DESCRIPTION

[0040] like Figure 1 As shown, the control method of the MTMD vibration reduction 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, perform modal analysis on the turnout frog area structure, and obtain the modal frequency, modal vibration shape, etc. of the turnout frog area structure 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 the harmonic response analysis of the turnout structure using finite element software, it is found that the first n-order vibration acceleration admittance of the structure is relatively high, and then the first n-order modes of the control turnout structure and the corresponding main vibration frequency are determined.

[0043] S3. Determine the nth-order modal vibration shape based on the modal analysis results of the finite element solid model of the turnout frog area, and determine the installation position of each sub-TMD at the point where the modal vibration shape displacement is maximum.

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

[0045] The parameter calculation expression of the first solution includes the following forms:

[0046] Mass ratio of tuned mass damper TMD:

[0047] Frequency ratio of tuned mass damper TMD:

[0048] Damping ratio of tuned mass damper TMD:

[0049] Where 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 the main structure.

[0050] The parameter calculation expression of the second solution includes the following forms:

[0051] Mass ratio of the tuned mass damper TMD of the i-th mode:

[0052] Frequency ratio of the i-th mode tuned mass damper TMD:

[0053]

[0054] The damping ratio of the tuned mass damper TMD for the i-th mode is:

[0055]

[0056] In the 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 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.

[0057] Modify the sub-TMD mass ratio of the two schemes, calculate the frequency ratio and damping ratio corresponding to 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, using the neutron TMD parameters of different MTMD systems designed in step S4.

[0059] The first scheme designs n sub-TMDs for the n-order mode and the main vibration frequency respectively. The parameters of each sub-TMD are different. The sub-TMDs are established in the finite element solid model, and the parameters of each sub-TMD are input to simulate the travel process and load conditions of the train in the turnout frog area to obtain the vibration acceleration response results of the switch center position.

[0060] The second scheme designs sub-TMDs for the nth-order mode and the main frequency of vibration, applies spring-damping mass units to the finite element solid model of the turnout, assigns parameters according to the calculated values, and 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 train travel process and load conditions in the turnout frog area are simulated to obtain the vibration acceleration response results at the switch center position.

[0061] Both the first and second schemes modify the mass ratio, frequency ratio, and damping ratio of the sub-TMD. Each scheme forms multiple groups of situations. The vibration displacement frequency response results are compared and analyzed to obtain the optimal parameters of the two schemes and the better scheme of the two schemes.

[0062] The modal analysis described in the present embodiment is a method for studying the dynamic characteristics of structures, which is generally used in the field of engineering vibration. Wherein, mode refers to the natural vibration characteristics of the main structure, and each mode has a specific natural frequency, damping ratio and modal vibration shape. The process of analyzing these modal parameters is called modal analysis. The modal analysis of the present 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, the natural frequency needs to be kept away from the excitation frequency to prevent resonance. The modal vibration type in this embodiment refers to the displacement distribution of each free vibration mode (i.e., mode) in the structural system when the system is excited to vibrate. Each vibration type represents the vibration morphology of the structure at a specific frequency.

[0064] Figure 2 The schematic diagram of the turnout frog area is shown in Figure 2. Based on the frog structure, the finite element model of the turnout frog area is established as follows: Figure 3 shown.

[0065] The vibration acceleration response results of the switch center position obtained by simulating the train's travel process and load conditions in the switch frog area are as follows: Figure 4 , Figure 5 As shown. Figure 4 It can be seen that under the MTMD optimal parameter conditions designed in the first scheme, the MTMD vibration reduction method obtained by the present invention has a significant effect on the vibration reduction of the turnout frog area structure. Figure 4 The present invention uses the finite element model of the turnout frog area MTMD established with the optimal mass ratio, frequency ratio, and damping ratio to calculate and simulate the train's travel process and load conditions in the turnout frog area, and obtains the vibration acceleration response result of the turnout center position. The calculation results can only reflect the effect of the first scheme under the optimal mass ratio, frequency ratio, and damping ratio parameters of MTMD.

[0066] Depend on Figure 5 It can be seen that under the MTMD optimal parameter conditions designed in the second scheme, the MTMD vibration reduction method obtained by the present invention has a significant effect on the vibration reduction of the turnout frog area structure. Figure 5 The present invention uses the finite element model of the turnout frog area MTMD established with the optimal mass ratio, frequency ratio, and damping ratio to calculate and simulate the train's movement process and load conditions in the turnout frog area, and obtains the vibration acceleration response result of the turnout center position. The calculation results can only reflect the effect of the second scheme under the optimal mass ratio, frequency ratio, and damping ratio parameters of MTMD.

[0067] like Figure 6 As shown, the present embodiment is a MTMD vibration reduction system for a turnout frog area under complex load conditions, which 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 a vibration reduction structure attached to the turnout 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 number of sub-TMDs, and the sub-TMDs include a damper 3, a spring 2, and a mass block 1; the damper 3 and the spring 2 are vertically installed on the mass block 1, and the damper 3 is 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 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 1 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 a control method of a switch frog area MTMD vibration reduction system under complex load conditions according to 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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