A metal mesh vibration damper, design method and system for rail transit

Abstract

The present invention belongs to the technical field of vibration data control and identification of vibration-damping elements, and discloses a wire mesh vibration absorber, design method and system for rail transit. By utilizing the structure in which a limit barrel and a limit guide column cooperate, the wire mesh block can suppress the vibration excited by the vertical excitation load during the actual operation of the rail transit vehicle, and meet the buffering of the lateral vibration during the turning, starting and emergency stop of the rail transit vehicle. The wire mesh block has different stiffness in each degree of freedom to meet the vibration reduction requirements of the rail transit vehicle in different degrees of freedom, and the variable stiffness characteristics of the wire mesh block are used to meet the vibration control requirements under different load conditions of the train. The present invention simplifies the structure of the shock absorber, reduces its weight, controls external vibration noise, and realizes the bidirectional vibration reduction of the wire mesh floor shock absorber in the three degrees of freedom of the train, namely the vertical, lateral and running directions, and adapts to the different vibration load characteristics of rail transit vehicles in different degrees of freedom.

Description

Technical Field

[0001] The present invention belongs to the technical field of vibration data control and identification of vibration-damping elements, and in particular relates to a metal wire mesh vibration damper for rail transit, a design method and a system. Background Art

[0002] The rapid development of science and technology and my country's transportation industry has made rail transit gradually become the mainstream choice for people to travel. As people's safety awareness increases, passengers have higher and higher requirements for train safety, comfort and reliability. Therefore, NVH (noise, vibration and ride smoothness) performance has gradually been used as a performance indicator to evaluate rail transit equipment.

[0003] (1) Rubber floor vibration damper

[0004] At present, in the field of rail transit, rubber damping materials are generally used to make floor vibration dampers for rail transit vehicles. This material has both viscosity and elasticity. Due to its high damping, light weight, good processability, low cost, and adjustable stiffness and damping, it has become the first choice for some conventional vibration isolation equipment. Commonly used rubber floor vibration dampers are composed of a support frame, rubber material and a fixing plate. The support frame and the fixing plate are generally made of A701S-T5 (aluminum profile), and the materials used in the rubber formula are all flame-retardant, low-smoke, non-toxic, low-halogen non-flammable materials or fireproof materials, and the hardness of the rubber is about 70±3 (ShoreA).

[0005] The rubber floor vibration damper is installed at the bottom of the carriage floor. The floating floor is placed on the support frame, and the frame structure at the bottom of the carriage is connected below. The floor mainly uses aluminum honeycomb floor or cork floor. The vibration damper support frame is fixed to the floor by bonding or bolts, and the fixing plate is fixed to the frame structure by bolts. The overall structure of the rubber floor vibration damping system includes the rail vehicle body and the floor vibration damping system.

[0006] When the train is running, due to the influence of external factors such as the geographical environment, the car body will be affected by many factors, such as vibration excitation between the wheel-rail and the track, vibration excitation from the environment, and vibration excitation from passengers walking on the car. These load excitations are weakened and attenuated through the rubber floor shock absorber. At the same time, it can also effectively control the external noise during the operation of the train, thereby ensuring the smooth operation of the train and the comfort requirements of the passengers.

[0007] (2) Wire Mesh Vibration Damper

[0008] Metal mesh shock absorbers are commonly used in aerospace, special vehicle equipment and other fields. Metal mesh blocks are made of stainless steel wire through processes such as wire selection, wire winding, stretching, weaving and compression molding. Its vibration reduction working mechanism mainly relies on the elastic strain, extrusion and friction slip between the wires to consume and store the energy generated by the vibration of the vehicle body. It has high damping and variable stiffness vibration reduction performance. Metal mesh materials can withstand high temperature, high pressure, high vacuum, and ultra-low temperature. They do not evaporate in space environments and are not afraid of space radiation and particle impact. Therefore, metal mesh shock absorbers have the characteristics of long storage and service life and no aging phenomenon. The prior art discloses a metal mesh shock absorber used on a certain armored vehicle (authorization announcement number CN106134402 B).

[0009] The shock absorber includes a mounting shaft, a cover, an upper mesh block, a lower mesh block, a sealing ring and a seat, and can meet the performance requirements of corrosion resistance, aging resistance, impact vibration resistance, etc. In addition, the wire mesh shock absorber can reduce the impact vibration of components such as the engine, clutch and gearbox relative to the vehicle body, improve the working environment of the power system, and increase the reliability and life of the power system.

[0010] Through the above analysis, the problems and defects of the prior art are as follows:

[0011] (1) Rubber floor shock absorber: The rubber floor shock absorber exhibits linear stiffness characteristics, and its shock absorption effect is poorly adaptable to different train loads. During the installation and use process, there are problems such as fatigue damage, permanent deformation, and difficulty in meeting high and low temperature, anti-aging, and corrosion resistance requirements. Therefore, during use, it is necessary to regularly inspect its use. If damage occurs, the car body must be disassembled and replaced immediately to ensure the stable and safe operation of the shock absorption system. The subsequent maintenance cost is too high. In addition, the rubber floor shock absorber has a slightly weaker ability to resist impact loads.

[0012] (2) Wire mesh shock absorbers: The existing wire mesh shock absorbers are too complex in structure and too heavy. Although they have good effects in vibration reduction and impact resistance, they have poor noise control. In addition, the floor system of rail transit vehicles will be subjected to vibration loads from various degrees of freedom, and the load characteristics of each degree of freedom are not the same. Traditional wire mesh blocks mostly adopt an axisymmetric structure, so that their radial (lateral) bearing stiffness and damping characteristics are consistent, and a single mesh block can only play a vibration reduction role when it is compressed in one direction. Therefore, the existing wire mesh shock absorbers cannot adapt to the vibration load characteristics generated during the operation of rail transit vehicles. At the same time, for rail transit, the floor shock absorber has strict space requirements, that is, the existing wire mesh shock absorbers cannot meet actual needs in terms of size, weight, etc. Summary of the invention

[0013] In order to overcome the problems existing in the related art, the disclosed embodiments of the present invention provide a metal mesh vibration damper, design method and system for rail transit. The purpose is to solve the problems existing in the rubber floor vibration damper in the field of rail transit, mainly including that the rubber material that plays a vibration damping role does not have the ability of variable stiffness, anti-aging, high and low temperature resistance, corrosion resistance, etc., and the existing metal mesh vibration damper is not suitable for the field of rail transit floor vibration damping; currently, no invention can solve the above two problems at the same time.

[0014] The technical solution is as follows: a metal wire mesh shock absorber for rail transit, which uses a structure that cooperates with a limit barrel and a limit guide column to suppress the vertical reciprocating load excitation of the metal wire mesh block during the actual operation of the rail transit vehicle, and meets the buffering of the lateral reciprocating vibration of the rail transit vehicle during turning, starting and emergency stopping. The different stiffness of the non-axisymmetric metal wire mesh block in each lateral direction is used to adapt to the vibration reduction needs of the rail transit vehicle in different degrees of freedom. At the same time, the variable stiffness characteristics of the metal wire mesh block are used to adapt to the vibration control needs of the train under different load conditions, and the occurrence of resonance can also be eliminated.

[0015] In one embodiment, the metal wire mesh block is made of stainless steel wire material.

[0016] In one embodiment, the wire mesh vibration damper for rail transit further comprises: a base, a cover plate, and the wire mesh block comprises: a first wire mesh block, a second wire mesh block;

[0017] There are two limit barrels, which are installed on two symmetrical holes in the base and welded in a circle with added material;

[0018] A second metal wire mesh block is placed in the base, and a cover plate is placed on the upper portion of the second metal wire mesh block;

[0019] On the bottom of the base, first metal wire mesh blocks are placed on the left and right sides of the limit barrel respectively and are limited in the limit barrel by limit guide pillars;

[0020] There are two limiting guide pillars; the two limiting guide pillars pass through the two first metal wire mesh blocks and the limiting barrel from the bottom respectively; the cover plate is connected to the two limiting guide pillars by riveting.

[0021] In one embodiment, the two threaded holes on the two wings of the base and the three threaded holes on the cover are used for connection with the external equipment body;

[0022] The metal wire mesh shock absorber for rail transit is installed at the bottom of the carriage floor, a floating floor is placed on the cover plate, and the base is connected to the frame structure at the bottom of the carriage; the floating floor uses an aluminum honeycomb floor or a cork floor, and the cover plate and the floating floor are fixedly connected by bonding or bolts; the base, the cover plate, the limit barrel and the limit guide column are all machined from metal materials, and the first metal wire mesh block and the second metal wire mesh block are made of metal wire through processes such as wire selection, wire winding, stretching, weaving and compression molding.

[0023] Another object of the present invention is to provide a design method for a metal wire mesh vibration damper for rail transit, comprising:

[0024] S1, model establishment: construct the mechanical model and mathematical model of the wire mesh shock absorber used in rail transportation;

[0025] S2, load excitation: excitation between wheel-rail and track; excitation of passengers on board; and vibration excitation of external environmental factors;

[0026] S3, based on the mechanical model and mathematical model constructed in step S1 and the load excitation information obtained in step S2, designing a metal wire mesh vibration absorber for rail transit, including designing the stiffness and damping of the metal wire mesh and designing the overall structure of the metal wire mesh vibration absorber for rail transit;

[0027] S4, based on the wire mesh shock absorber designed in step S3 for rail transit, conduct simulation experiments to verify that the shock absorber performance meets the requirements of the rail transit floor shock absorption system, including: adaptive shock absorption effect in the three degrees of freedom of the train vertical, lateral and running direction; shock absorption effect under different passenger capacities; two-way shock absorption in a single degree of freedom; lightweight requirements; installation space requirements; vibration and noise control. The feasibility of the designed shock absorber is verified through the shock absorption test of the high-speed train wire mesh floor shock absorption system.

[0028] In one embodiment, in step S1, constructing a mechanical model of a wire mesh vibration damper for rail transit includes:

[0029] Assume that m is the mass of the vibration reduction body of the rail transit train, k is the linear coefficient of the spring, β is the nonlinear coefficient of the spring, c is the viscous damping coefficient, Y(t) is the dry friction force when the wire mesh block slides, and x is the output displacement vector of the wire mesh floor vibration reduction system of the rail train; analyze the force of the floor vibration reduction system and list the motion differential equation of the system according to Newton's second law of motion: Where Y(t) = k s ·x s , x s is the deformation displacement vector when slip begins, k sis the linear stiffness before slip; P(t) is the load vector of the rail train vibration system, P(t)=[S(t),S u (t),F(t)], where S(t) is the track irregularity load input excitation, S u (t) is the load input excitation under the action of crosswind, and F(t) is the load input excitation of continuous walking.

[0030] In one embodiment, in step S2, the excitation between the wheel rail and the track, the excitation of the passengers on the vehicle, and the vibration excitation of the external environmental factors include:

[0031] When rail vehicles are in operation, the vibration excitation from the unevenness between the wheel-rail and the track, the vibration excitation from the movement of passengers in the car and the vibration excitation from external environmental factors will transfer the vibration of the train to the floor vibration damping system. The wire mesh floor vibration damper consumes and stores the energy generated by the vibration of the car body through the elastic strain, extrusion and friction slip between the internal wire meshes.

[0032] During the vertical vibration of the vehicle body, the structure of the limit barrel and the limit guide column can make the first metal wire mesh block and the second metal wire mesh block play a role alternately. The first metal wire mesh block is used to bear the upward tensile excitation, and the second metal wire mesh block is used to bear the downward ballast excitation, so that the vibration response of the ballast excitation and the tensile excitation is suppressed;

[0033] When the train turns, starts or stops suddenly, the base, the limit barrel, the limit guide column and the cover plate cooperate with each other, and the second metal wire mesh block bears the reciprocating extrusion effect of the lateral vibration load.

[0034] The second wire mesh block has a greater stiffness along the running direction of the rail transit train than the vertical stiffness, and has a stronger bearing capacity, so as to meet the suppression of more severe impact vibration response generated when the train starts, changes speed and stops suddenly. In addition, the second wire mesh block can also buffer the lateral vibration load generated when the train turns.

[0035] Among them, the excitation between the wheel, rail and track, the excitation of passengers on the train and the vibration excitation of external environmental factors specifically include the following:

[0036] Between wheel rail and track:

[0037] Track lines are the most important infrastructure in train operation. Their main function is to guide trains, bear the weight of their own structure and passengers transmitted by the train wheels, and transmit and disperse it to the roadbed. Track excitation usually refers to track unevenness excitation. Track unevenness usually refers to the actual deviation of the geometric dimensions of two parallel track lines from the ideal state. Track geometric unevenness is one of the external excitation factors that cause vibration during train operation. Track excitation causes vertical and lateral coupled vibrations of trains, which not only limits the safe speed of train operation, but also affects the transportation volume and traffic volume of railway lines. Track unevenness excitation can be divided into the following four types, as shown in Figure 7 (a) for height unevenness; Figure 7 (b) for directional unevenness; Figure 7 (c) for horizontal unevenness and gauge unevenness.

[0038] The actual track irregularity excitation is composed of the superposition of simple harmonic vibrations with varying amplitudes, variable frequencies, and different phase angles. It is a random function that changes over the track mileage. By using mathematical statistics methods to collect and analyze a large amount of track irregularity data and perform curve fitting on the data, a track irregularity power spectrum suitable for railway lines is obtained, which is used as an external excitation input for train dynamics analysis to study the running quality of the train. Through comparative analysis of domestic and foreign track power spectra, the present invention uses the high and low irregularities of Germany's low-interference tracks as the track excitation analysis object and performs track spectrum time domain conversion. The present invention uses the inverse Fourier transform method to directly perform discrete sampling processing on the power spectrum density function to obtain the corresponding frequency spectrum, and then performs inverse Fourier transform processing on the sequence to calculate the track irregularity function in time domain form. The fitting formula for the train track irregularity power spectrum density is S(n)=A·n -k , through the formula And f = v·n, Δf = v·Δn, the function of power spectrum density with respect to spatial frequency n can be converted into a function with respect to temporal frequency f: S(f) = A·v k-1 ·f k The core idea of ​​the inverse Fourier transform method is to convert the single-sided spectrum into a double-sided spectrum according to the power spectrum density value. By performing an inverse Fourier transform on the double-sided spectrum, the simulated track irregularity time domain sequence can be obtained. After determining each parameter and converting the single-sided spectrum into the double-sided spectrum, the spectrum modulus value can be calculated from the conversion relationship between the spectrum modulus value and the power spectrum density value: X(k) is the Fourier transform of the track irregularity time-domain sequence x(k) to be simulated, and |X(k)| represents the amplitude of the harmonic with frequency f=k·Δf in the harmonic component of the time-domain sequence x(k). Through the above steps, the frequency and amplitude of each harmonic are known, but the initial phase is unknown. Due to the randomness of the time-domain sequence, the initial phase of each harmonic is It is regarded as a random variable that obeys a uniform distribution within 0 to 2π, so the expression of X(k) within the entire sampling frequency can be obtained as: Through the above method, the frequency, amplitude, and initial vibration phase of each harmonic can be obtained. The track irregularity function S(t) of the high-speed train is formed by superimposing each harmonic.

[0039] Vibration excitation from external environmental factors:

[0040] The vibration excitation of external environmental factors mainly considers the influence of air flow. Research on the aerodynamic performance of high-speed trains shows that the aerodynamic characteristics of trains will change under the action of strong side winds, including the aerodynamic lift, lateral force and overturning moment, which will affect the running stability and safety of the train. High-speed trains are very prone to accidents under the action of strong winds, threatening the lives and property safety of passengers.

[0041] The frequency domain characteristics of the fluctuating wind speed can be obtained through the wind speed power spectrum. The horizontal fluctuating wind speed power spectrum is described as follows: Among them, u * is the friction wind speed (shear wind speed); and is the average wind speed at height z, and n is the frequency of the wind (1 / s). In the formula, K is a dimensionless constant, K≈0.4; is the average height of surrounding buildings (m); Z0 is the ground roughness height (m). By performing inverse discrete Fourier transform on the wind speed power spectrum density function, we can obtain the pulsating wind time domain curve function S under different wind speeds, different heights, and different surrounding environments. u (t), the time domain curve function S u (t) is used as the load input excitation under crosswind action.

[0042] Encouragement for passengers on board:

[0043] Starting from the basic physical principles of human walking behavior, the continuous walking incentive of a person on a horizontal plane is analyzed. By summarizing the study of a person's single-step landing curve, the present invention finds that the center of gravity of a person is always rising and falling during walking, and the distance of up and down fluctuations is about 35mm for a person of average height. In fact, when a person walks, the force exerted on the ground is not always equal to the person's weight G, but a fluctuating value. At the moment when the sole of the foot touches the ground, this force is more or less greater than G. The step frequency f s It represents the number of steps a person takes per unit time and is another important parameter of the walking excitation time course. It determines the main frequency component of the walking excitation time course. Experimental studies have shown that the walking frequency f of an average person is sAround 1.9Hz. The stride is the distance a person takes in one step. When determining the number of steps a person needs to take to walk from point A to point B in a structure, the size of the stride needs to be considered. The size of the stride and the height of a person satisfy a simple proportional relationship dy=0.45H. Studies have found that the stride dy roughly follows a normal distribution with a mean of 0.71m and a variance of 0.071m. And when a person walks, there is a time period during which the left and right feet touch the ground at the same time. The overlapping time is related to the step frequency. The lower the step frequency, the longer the single-step landing curve lasts, and the longer the overlapping time dt is. Therefore, when using a single-step landing curve, it is necessary to clarify the actual step frequency f corresponding to the curve. s After knowing the single-step landing curve and its corresponding step frequency, the overlap time can be calculated according to To calculate, where t s represents the total duration of a single-step landing curve, f s Represents the step frequency. Assuming that the single-step landing curves generated by the left and right feet of a person are the same, the complete walking excitation force time history curve can be defined based on the single-step landing curve and the overlapping time. Considering the actual application, the influence of high-order simple harmonics can be ignored, and only the first-order simple harmonics that play the most role in the dynamic load are considered, and then the continuous walking excitation model of a person is simplified, and the load function of the simplified model is obtained as follows: F(t) = G[1+α1sin(2πf s t)], where G represents the average weight of a person, which is 0.7 kN; α1 represents the dynamic load factor of the first-order simple harmonic wave, which is 0.5; f s Indicates the step frequency, which is 1.9Hz.

[0044] In one embodiment, in step S3, the static characteristics of the wire mesh floor damper are analyzed through a static compression test to obtain the relationship between static stiffness and damping change; and the action mechanism of the wire mesh block during the internal wire-to-wire state when it is loaded, the free state when not in contact, the orthogonal sliding process when in contact, and the extrusion stage during parallel sliding is analyzed.

[0045] Another object of the present invention is to provide a simulation design system for a metal mesh vibration damper for rail transit, which runs on a client, and the simulation design system for a metal mesh vibration damper for rail transit comprises:

[0046] Model building module, used to build mechanical and mathematical models of wire mesh shock absorbers for rail transit;

[0047] Load excitation simulation module, used to simulate the excitation between wheel-rail and track; the excitation of passengers on the train; and the vibration excitation of external environmental factors;

[0048] The module for acquiring the overall structure of the shock absorber is used to design the metal wire mesh shock absorber for rail transit based on the constructed mechanical model and mathematical model and the obtained load excitation information, including the design of the stiffness and damping of the metal wire mesh and the design of the overall structure of the metal wire mesh shock absorber for rail transit;

[0049] The simulation module is used to simulate the performance of the designed wire mesh shock absorber for rail transit and to test whether the shock absorber meets the requirements of the rail transit floor shock absorption system, including: adaptive shock absorption effect in the three degrees of freedom of the train vertical, lateral and running direction; shock absorption effect under different passenger capacities; bidirectional shock absorption in a single degree of freedom; lightweight requirements; installation space requirements; vibration and noise control. The feasibility of the designed shock absorber is verified through the shock absorption test of the high-speed train wire mesh floor shock absorption system.

[0050] Combining all the above technical solutions, the advantages and positive effects of the present invention are as follows:

[0051] First, in view of the problems existing in the above-mentioned prior art and the difficulty of solving the problems, the technical solution to be protected by the present invention and the results and data during the research and development process are closely combined to analyze in detail and deeply how the technical solution of the present invention solves the technical problems and some creative technical effects brought about after solving the problems. The specific description is as follows:

[0052] Compared with the existing rubber floor shock absorber, the present invention adopts metal wire mesh blocks to replace traditional rubber damping materials, which can better adapt to and improve the shock absorber's ability to withstand complex service environments; the present invention has the advantages of oil resistance, corrosion resistance, temperature difference resistance, radiation resistance, high and low temperature resistance, aging resistance and small size, is suitable for working in harsh comprehensive environments, is applicable to a wider range of working conditions, and has a long service life, which can reach the same life as the main body of the equipment equipped with the shock absorber, so it does not need to be replaced frequently, reducing maintenance costs.

[0053] Compared with the existing wire mesh shock absorbers, the present invention creatively uses a structure in which a limit barrel and a limit guide column are used in combination, which cleverly solves the shortcoming that the wire mesh block cannot withstand the pulling load, so that the present invention can be applied to the vertical reciprocating load excitation conditions during the actual operation of rail vehicles; in addition, the present invention can also meet the vibration reduction requirements of the lateral reciprocating vibration during the train turning, starting and emergency stopping, and the different stiffness in each degree of freedom also adapts to the suppression requirements of its excitation load characteristics, that is, the shock absorber can meet the vibration reduction requirements of rail vehicles in different degrees of freedom. At the same time, the variable stiffness characteristics of the wire mesh block can adapt to the vibration control requirements under different load conditions of the train, and also avoid the occurrence of resonance. Moreover, the structure of the present invention is simpler and lighter, which meets the lightweight requirements of the train floor shock absorber, and can also control the external noise to a considerable extent as the rubber floor shock absorber.

[0054] The wire mesh block made of AISI 304 wire material in the present invention has a gradually changing stiffness characteristic, that is, as the load increases, the stiffness and displacement decrease, the vibration intensity is low, the vibration amplitude is small, and the damping is large. Moreover, under the condition of bearing the same load, the wire mesh shock absorber has the smallest volume size and a compact structure, which is beneficial to the overall layout of the vehicle. Therefore, its shock absorption performance is more excellent and can meet the installation space requirements of the floor shock absorber of rail transportation vehicles to the greatest extent.

[0055] The present invention combines the analysis of the working principle, characteristics and hysteresis loop of the wire mesh vibration absorber and the load characteristics of the rail train during operation, designs a rectangular wire mesh vibration absorber with stiffness and damping characteristics that are adapted to the vibration load of the floor system at different degrees of freedom, and determines the stiffness and damping parameters of the wire mesh floor vibration absorber and its action structure.

[0056] First, in the vertical direction of the train, due to the change in the passenger capacity in the car, the vibration excitation generated is also changing. When the rail transit vehicle is unloaded, the vibration excitation is small, and the stiffness of the wire mesh floor damper changes little at this time, and the deformation has linear elastic characteristics, which can meet its vibration reduction performance requirements; when the rail transit vehicle is half loaded, the mass of the overall vibration reduction equipment increases, so its vibration load also increases accordingly, the compression density of the wire mesh floor damper mesh block increases, and its stiffness also increases accordingly, so the ability of the damper to withstand the vibration load also adapts to the change in the mass of the vibration reduction equipment; and when the rail transit vehicle is fully loaded, the load increases to a certain extent, so that the wire mesh damper mesh block at this time presents a hard stiffness characteristic, that is, although it bears a large vibration load, the vibration response of the floor system is very small, and the vibration displacement is not severe. This static stiffness curve adapts to the characteristics of the ever-changing passenger capacity of rail transit vehicles to a great extent, so that the entire floor system can fully play its role under different road conditions and different passenger capacities. And because the floor vibration reduction system has variable stiffness (variable frequency) characteristics, the possibility of resonance is avoided, which is also a protection for rail transit vehicles.

[0057] Secondly, in the running direction of the rail train, the rail transit vehicle needs to start, change speed and stop urgently due to running requirements or when some emergency situations occur. At this time, the floor system of the rail transit vehicle will be subject to a large excitation load in the running direction of the train, and under different passenger capacities, the magnitude of this excitation load is obviously different.

[0058] The lateral vibration load of the rail train is mainly caused by the turning of the train. Due to the relatively gentle turning characteristics of the rail transit wheel and rail, the vibration load in this direction is relatively small. Therefore, a rectangular wire mesh floor shock absorber is finally designed, so that its stiffness in the three degrees of freedom of the train vertical, lateral and running directions is different, and it adapts to the characteristics of the vibration load in each degree of freedom of the floor shock absorption system of the rail transit vehicle, that is, the larger the vibration load, the larger the stiffness of the shock absorber in this degree of freedom. In addition, in order to meet the two-way vibration reduction in a single degree of freedom, the limit guide column and the limit barrel are designed in the shock absorber structure, so that the second wire mesh block can withstand the downward ballast load, and the first wire mesh block can withstand the upward tensile load, which solves the problem that the wire mesh block can only bear one-way load. And the second wire mesh block can also give full play to its adaptive vibration reduction performance with the cooperation of the base, cover plate, limit barrel and limit guide column for the reciprocating vibration load in the lateral and running directions of the train. In addition, the structure of the present invention is more compact than the previous metal wire mesh damper, does not require additional nested sealing rings, and has a reduced overall mass. Therefore, the size and weight of the present invention can meet the lightweight requirements and installation space requirements for floor dampers in the field of rail transit. In terms of vibration noise control, the molding method of the metal wire mesh block determines that its internal structure is not a dense structure, and its loose and porous metal structure can achieve the sound insulation and sound absorption effects of rail transit to a certain extent.

[0059] Second, considering the technical solution as a whole or from the perspective of the product, the technical effects and advantages of the technical solution to be protected by the present invention are described in detail as follows:

[0060] The invention improves the ability of the floor vibration absorber to resist oil, corrosion, temperature difference, radiation, high and low temperature, aging and fatigue damage.

[0061] The present invention designs a metal wire mesh vibration damper suitable for rail transit working conditions and installation space requirements, utilizes the damping nonlinearity and stiffness nonlinearity of the metal wire mesh block to adapt to the different load-bearing requirements of rail transit, and improves the vibration reduction capacity of the overall floor vibration reduction system.

[0062] The present invention simplifies the structure of the shock absorber, reduces its weight, controls external vibration noise, realizes bidirectional vibration reduction of the metal wire mesh floor shock absorber in three degrees of freedom of the train vertical, lateral and running directions, and adapts to the different vibration load characteristics of rail vehicles with different degrees of freedom.

[0063] Third, as auxiliary evidence of the inventiveness of the claims of the present invention, it is also reflected in the following important aspects:

[0064] (1) The present invention uses metal mesh materials, which are not prone to corrosion and aging. After being loaded on high-speed trains, they do not need to be replaced or overhauled regularly, which greatly reduces the installation and maintenance costs of the shock absorber. In addition, the control of performance parameters such as the stiffness of the metal mesh block has made great breakthroughs in processing technology, and the manufacturing cost of the shock absorber has also been guaranteed to a certain extent.

[0065] (2) The present invention creatively applies metal wire mesh vibration damping materials used in high-tech fields such as aerospace to the high-speed train floor vibration damper industry, which is a first in China and abroad.

[0066] (3) Compared with traditional rubber shock absorbers, the present invention has superior vibration reduction performance, which largely solves the problem of increasingly severe vibration caused by the continuous increase in the running speed of high-speed trains, and provides technical support for the research and development of faster high-speed trains.

[0067] (4) The present invention breaks the long-standing monopoly of rubber shock absorbers in the high-speed train floor shock absorber industry and achieves an innovative technological breakthrough in the field of floor shock absorption. BRIEF DESCRIPTION OF THE DRAWINGS

[0068] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0069] Figure 1 is a flow chart of a design method of a metal mesh vibration damper for rail transit provided by an embodiment of the present invention;

[0070] Figure 2 Schematic diagram of the structure of a metal wire mesh vibration absorber for rail transit provided by an embodiment of the present invention;

[0071] Figure 3 is a top view of a metal wire mesh vibration damper structure for rail transit provided by an embodiment of the present invention;

[0072] Figure 4 It is a simplified diagram of the mechanical model of the metal wire mesh floor vibration absorber excited by external load provided by an embodiment of the present invention;

[0073] Figure 5 It is a schematic diagram of a static characteristic curve of a metal wire mesh floor vibration absorber analyzed by a static compression test provided by an embodiment of the present invention;

[0074] Figure 6 It is a schematic diagram of a simulation design system of a metal mesh vibration damper for rail transit provided by an embodiment of the present invention;

[0075] FIG. 7( a ) is a track unevenness excitation diagram provided by an embodiment of the present invention;

[0076] FIG. 7( b ) is a track direction irregularity excitation diagram provided by an embodiment of the present invention;

[0077] FIG. 7( c ) is an excitation diagram of horizontal irregularity and track gauge irregularity provided by an embodiment of the present invention;

[0078] Figure 8 is a block diagram of a static test system provided by an embodiment of the present invention;

[0079] FIG9( a ) is a test displacement curve diagram of the shock absorber in the load variation range of 0 to 8 KN provided in an embodiment of the present invention;

[0080] FIG9( b ) is a test displacement curve diagram of the shock absorber in the load variation range of 4 to 12 KN provided in an embodiment of the present invention;

[0081] Fig.10 Schematic diagram of a high-speed train floor vibration reduction system provided by an application embodiment of the present invention;

[0082] Fig.11 It is a layout diagram of a metal mesh floor vibration damper provided by an application embodiment of the present invention;

[0083] Fig.12 It is a test data diagram of a certain measuring point provided by an application embodiment of the present invention;

[0084] In the figure: 1. base; 2. limit barrel; 3. first metal wire mesh block; 4. limit guide column; 5. cover plate; 6. second metal wire mesh block; 7. model building module; 8. load excitation simulation module; 9. shock absorber overall structure acquisition module; 10. simulation experiment simulation module. DETAILED DESCRIPTION

[0085] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific implementation disclosed below.

[0086] 1. Explanation of the embodiment:

[0087] The embodiment of the present invention proposes for the first time to use metal wire mesh blocks for floor vibration reduction in the field of rail transportation. The key innovations include:

[0088] The coordinated use of the limit barrel 2 and the limit guide post 4 enables the second metal mesh block 6 to withstand downward pressure excitation, and the first metal mesh block 3 to withstand upward tension excitation, solving the problem that the metal mesh block can only bear load in one direction. In addition, the second metal mesh block 6 can also give full play to its adaptive vibration reduction performance in response to the reciprocating vibration load in the lateral and running directions of the train under the coordination of the base 1, the cover plate 5, the limit barrel 2 and the limit guide post 4.

[0089] The innovation of the present invention lies in: designing a rectangular wire mesh block to adapt to the different characteristics of vibration loads on each degree of freedom borne by the rail transit floor vibration reduction system. The wire mesh vibration absorber has different stiffness and damping in the three degrees of freedom of the vertical, lateral and running directions of the train, and the ability to withstand vibration loads is also different. Therefore, it adapts to the vibration reduction requirements of the vertical tension and compression and lateral reciprocating vibration of the train operation, and realizes the optimal parameter design for the vibration reduction effect on each degree of freedom.

[0090] During the operation of high-speed trains, the train is mainly subjected to vibration excitation from passengers walking and between wheels, rails and tracks in the vertical direction, and mainly subjected to lateral extrusion vibration excitation from external air flow factors in the lateral direction, while in the running direction of the train, it is mainly subjected to vibration excitation caused by load changes when the high-speed train starts, stops and changes speed. Therefore, in order to adapt to different load characteristics, the stiffness and damping parameters of the wire mesh shock absorber in the three degrees of freedom of the vertical, lateral and running directions of the train are adjusted and designed, and the feasibility of the designed shock absorber is verified through the vibration reduction test of the high-speed train wire mesh floor shock absorption system.

[0091] The more simplified and ingenious structure of the present invention can also meet the requirements of lightweight floor vibration absorbers and strict installation space limitations and vibration and noise control.

[0092] The shock absorber shell provided by the present invention weighs 0.200kg, and the shell is made of 7075-T6 plate material, and its density is 2810kg / m 3 ; The volume of the first wire mesh block 3 is 2356.194mm 3 The volume of the second wire mesh block 6 is 72434.145mm 3 , the total volume of the wire mesh block is 77146.533mm 3 The mesh material is AISI304, and the material density is 8000kg / m 3 , mesh density is 4543kg / m 3 The total mass of the mesh block is 0.350kg. The total mass of the shock absorber of the present invention is 0.550kg, which is equivalent to the mass of the rubber shock absorber used in the original high-speed train. In the case of limited space and mass of the floor shock absorber, the present invention has better vibration reduction and noise reduction control capabilities.

[0093] The present invention is applicable to a wider range of working conditions, and metal materials have more obvious advantages over rubber materials in terms of installation, service life and subsequent maintenance costs.

[0094] like Figure 1 As shown, the design method of the metal mesh vibration damper for rail transit provided by the embodiment of the present invention includes:

[0095] S1, model establishment: construct the mechanical model and mathematical model of the wire mesh shock absorber used in rail transportation;

[0096] S2, load excitation: excitation between wheel-rail and track; excitation of passengers on board; and vibration excitation of external environmental factors;

[0097] S3, based on the mechanical model and mathematical model constructed in step S1 and the load excitation information obtained in step S2, designing a metal wire mesh vibration absorber for rail transit, including designing the stiffness and damping of the metal wire mesh and designing the overall structure of the metal wire mesh vibration absorber for rail transit;

[0098] S4, based on the wire mesh shock absorber designed in step S3 for rail transit, conduct simulation experiments to verify that the shock absorber performance meets the requirements of the rail transit floor shock absorption system, including: adaptive shock absorption effect in the three degrees of freedom of the train vertical, lateral and running direction; shock absorption effect under different passenger capacities; two-way shock absorption in a single degree of freedom; lightweight requirements; installation space requirements; vibration and noise control. The feasibility of the designed shock absorber is verified through the shock absorption test of the high-speed train wire mesh floor shock absorption system.

[0099] The design method of the metal mesh vibration damper for rail transit provided in the embodiment of the present invention solves two key problems existing in the existing vibration dampers, and not only improves the ability of the floor vibration damper to resist aging, high and low temperature and fatigue damage, but also effectively simplifies the vibration damper structure, realizes the bidirectional vibration damping of the metal mesh floor vibration damper in multiple degrees of freedom, and further improves the adaptive vibration damping performance of the rail transit floor vibration damping system in different degrees of freedom.

[0100] Specific gain effects include:

[0101] Compared with the existing rubber floor vibration absorber, the present invention adopts metal wire mesh blocks to replace traditional rubber damping materials, which can better adapt to and improve the ability of the vibration absorber to withstand complex service environments; the present invention has the advantages of oil resistance, corrosion resistance, temperature difference resistance, radiation resistance, high temperature resistance, aging resistance and small size, is suitable for working in harsh comprehensive environments, is applicable to a wider range of working conditions, and has a long service life, which can reach the same life as the main body of the equipment equipped with the vibration absorber, so it does not need to be replaced frequently, reducing maintenance costs.

[0102] Compared with the existing wire mesh shock absorbers, the present invention creatively uses a structure in which a limit barrel 2 and a limit guide column 4 are used in conjunction with each other, which cleverly solves the shortcoming that the wire mesh block cannot withstand the pulling load, so that the present invention can be applied to the vertical reciprocating load excitation conditions during the actual operation of rail vehicles; in addition, the present invention can also meet the vibration reduction requirements of the lateral reciprocating vibration during the train turning, starting and emergency stopping, and the different stiffness in each degree of freedom also adapts to the suppression requirements of its excitation load characteristics, that is, the shock absorber can meet the vibration reduction requirements of rail vehicles in different degrees of freedom. At the same time, the variable stiffness characteristics of the wire mesh block can adapt to the vibration control requirements of the train under different load conditions, and also avoid the occurrence of resonance. Moreover, the structure of the present invention is simpler and lighter, which meets the lightweight requirements of the train floor shock absorber, and can also control the external noise to a considerable extent as the rubber floor shock absorber.

[0103] The embodiment of the present invention adopts AISI 304 (AISI 304 (1.4301)), which is a widely used austenitic chromium-nickel stainless steel. It has excellent tensile properties and very good formability, while also having a high degree of corrosion resistance. Typical uses of 304 stainless steel include kitchen equipment such as sinks, pans, pipes, etc. Type 304 is sometimes also called 18 / 8, a name derived from its typical 18% chromium and 8% nickel composition. Other elements in the alloy include nickel, manganese, silicon, nitrogen, carbon, phosphorus and sulfur. Chemical composition of AISI 304: AISI 304 typically contains 17.5-19.5% chromium, 8-10.5% nickel, 2% manganese, 1% silicon, 0.11% nitrogen, 0.07% carbon, 0.05% phosphorus and 0.03% sulfur.

[0104] The wire mesh block made of metal wire material has the characteristics of hardness, that is, as the load increases, the stiffness and displacement decrease, the vibration intensity is low, the vibration amplitude is small, the damping is large, and under the condition of bearing the same load, the wire mesh shock absorber has the smallest volume size and compact structure, which is beneficial to the overall layout of the vehicle. Therefore, its vibration reduction performance is more excellent and can meet the installation space requirements of the floor shock absorber of rail transit vehicles to the greatest extent.

[0105] Example 1

[0106] An embodiment of the present invention provides a metal mesh shock absorber for rail transit. The metal mesh shock absorber for rail transit utilizes a structure in which a limit barrel 2 and a limit guide column 4 cooperate to enable the metal mesh block to suppress the vibration excited by the vertical excitation load during the actual operation of the rail transit vehicle, and to meet the buffering requirements of the lateral reciprocating vibration during the turning, starting and emergency stopping of the rail transit vehicle. The different stiffness of the metal mesh block in each degree of freedom is utilized to adapt to the vibration reduction requirements of the rail transit vehicle in different degrees of freedom. At the same time, the variable stiffness characteristics of the metal mesh block are utilized to adapt to the vibration control requirements under different load conditions of the train, and the occurrence of resonance can also be eliminated.

[0107] Example 2

[0108] like Figure 2 As shown, in order to solve the problems existing in the prior art, the embodiment of the present invention provides a new type of metal wire mesh shock absorber for rail transit, including: a base 1, a limit barrel 2, a first metal wire mesh block 3, a limit guide column 4, a cover plate 5, and a second metal wire mesh block 6.

[0109] The embodiment of the present invention fully analyzes the particularity of the size of the shock absorber loading space in the field of rail transit and the characteristics of the vibration load generated by it, and designs a rectangular metal wire mesh block that can fully withstand and reduce the vibration response of each degree of freedom of the equipment body. In addition, through the coordinated use of the first metal wire mesh block 3 and the second metal wire mesh block 6, the metal wire mesh shock absorber for rail transit provided by the embodiment of the present invention overcomes the defect that the metal wire mesh block can only withstand unidirectional compressive load. Figure 3 It is a top view of a metal mesh vibration damper structure for rail transit provided by an embodiment of the present invention.

[0110] Two limit barrels 2 are installed on two symmetrical holes in the groove of the base 1, and are welded in a circle with added materials; then, after the second wire mesh block 6 is placed in the base 1, the cover plate 5 is covered; the two first wire mesh blocks 3 are placed in the limit barrels 2 from the bottom of the base 1; then, the two limit guide pillars 4 are passed through the first wire mesh block 3 and the limit barrel 2 from the bottom respectively; the cover plate 5 and the two limit guide pillars 4 are connected together by riveting. The two threaded holes on the two wings of the base 1 and the three threaded holes on the cover plate 5 are used to connect the shock absorber to the main body of the equipment; the wire mesh floor shock absorber is installed at the bottom of the car floor, and the floating floor is placed on the cover plate 5, and the frame structure of the bottom of the car is connected to the bottom of the base 1. The floor mainly uses aluminum honeycomb floor or cork floor, and the shock absorber cover plate 5 is fixed to the floor by bonding or bolts, and the base 1 is fixed to the frame structure by bolts. The base 1, cover plate 5, limit barrel 2 and limit guide column 4 are all machined from metal materials, and the first metal wire mesh block 3 and the second metal wire mesh block 6 are made of metal wire through processes such as wire selection, wire winding, stretching, weaving and molding.

[0111] Two limit barrels 2 are installed on two symmetrical holes in the groove of the base 1, and a circle of material is added and welded to fix the limit barrels 2 on the base 1 to prevent them from displacement when subjected to vibration loads; then after placing the second metal mesh block 6 in the base 1, cover the cover plate 5, the second metal mesh block 6 is restricted in the groove by the base 1 and the limit barrel 2, and is mainly used to withstand the vertical downward ballast and the reciprocating vibration load in the lateral direction and the train running direction; two first metal mesh blocks 3 are placed in the limit barrel 2 from the bottom of the base 1, and the first metal mesh block 3 is used to withstand the vertical upward tensile load; then two limit guide pillars 4 are respectively passed through the first metal mesh block 3 and the limit barrel 2 from the bottom; the cover plate 5 is connected to the two limit guide pillars 4 by riveting. The limit guide pillar 4 is used to fix the position of the first metal mesh block 3 so that the first metal mesh block 3 can play a normal vibration reduction role; at the same time, the cover plate 5 is connected to the limit guide pillar 4 by riveting to provide support for the limit guide pillar 4. The cover plate 5 is designed with three threaded holes for fixed connection with the floating floor, while the threaded holes on the two wings of the base 1 play a role in connecting with the car frame structure.

[0112] When rail transit vehicles are in operation, the vibration of the train is transmitted to the floor vibration reduction system under the influence of the uneven vibration excitation from the wheel-rail and track, the vibration excitation from the movement of passengers in the car and the vibration excitation from external environmental factors. The wire mesh floor vibration absorber consumes and stores the energy generated by the vibration of the car body through the elastic strain, extrusion and friction slip between the internal wire meshes, thereby playing a role in vibration isolation and vibration reduction in the car. During the vertical vibration of the car body, the structure of the limit barrel 2 and the limit guide column 4 enables the first wire mesh block 3 and the second wire mesh block 6 to play a role alternately. The first wire mesh block 3 is subjected to upward tensile excitation, and the second wire mesh block 6 is subjected to downward ballast excitation, so that the vibration responses of ballast excitation and tensile excitation are suppressed; in the case of train turning, starting or emergency stop, the second wire mesh block 6 and the mutual cooperation between the various components are relied on to withstand the reciprocating vibration load of lateral extrusion. Since the vibration load generated when the train starts or stops suddenly is larger, and the vibration load generated when turning is smaller, in order to meet the vibration load characteristics of different degrees of freedom, the second wire mesh block 6 of the shock absorber is designed to have greater stiffness along the direction of train operation than the direction perpendicular to the train, and has a stronger ability to withstand vibration loads, which can better suppress the impact vibration response generated when the train starts and stops suddenly; in addition, it can also have a buffering effect on the lateral vibration load generated when the train turns.

[0113] Thus, the vibration reduction performance requirements of the floor of rail transit vehicles are fully met, and the metal wire mesh vibration damper can structurally play a role in controlling external vibration noise to the same extent as the rubber floor vibration damper.

[0114] Example 3

[0115] Based on the wire mesh vibration damper for rail transit described in Example 2, further, the operation principle implementation steps include:

[0116] When rail vehicles are running, their speed will change due to factors such as starting, stopping, and changes in road conditions. Therefore, the vibration excitation force generated by its wheels and rails will also change accordingly, and its amplitude and frequency are not fixed. According to the excitation test results of the actual rail vehicle line of the researchers, the excitation of the rail vehicle floor system is mostly random excitation, so the vibration of the vibration reduction system should be forced vibration of random excitation. As the frequency and amplitude of the excitation force change, the vibration excitation of each degree of freedom of the floor vibration reduction system is not the same, so the vibration reduction effect will be very different. In addition, during the operation of rail vehicles, the load borne by the floor vibration reduction system mainly includes the mass of the car seats and passengers in the car body. The mass of the seat is constant, but the number of passengers changes with the operation section and time, and may be empty, half-loaded or fully loaded. Therefore, the load borne by the floor vibration reduction system when in use is not fixed. Passengers and seats vibrate along with the floor vibration reduction system, so when the load changes, its natural frequency will change. When forced vibration occurs, the stress and strain generated by the floor vibration reduction system under the same excitation force will be different, and the vibration reduction effect of the floor vibration reduction system will also be affected to a certain extent. Based on the characteristics of vibration excitation of the floor system of rail transportation vehicles, the vibration reduction effect of traditional shock absorbers is limited, and the shortcomings of easy aging and fatigue gradually require the present invention to design better performance vibration reduction elements.

[0117] Metal mesh vibration dampers are often used in high-precision products. Since the metal mesh block is woven, wound, and molded with metal wire materials, the internal material is evenly distributed with the metal wire and has a consistent density. The metal mesh block absorbs and dissipates vibration energy by elastic strain, extrusion, and friction slip during the compression process. Therefore, as the load continues to increase, the compression density of the mesh block continues to increase. At this time, the load capacity of the mesh block per unit displacement deformation will increase rapidly, showing a gradual hardness characteristic. Therefore, the metal mesh block has strong damping nonlinearity and stiffness nonlinearity, and both damping and stiffness are large, which can play a good role in vibration reduction and buffering.

[0118] The mathematical model of the wire mesh floor vibration reduction system excited by external load is established: m is the mass of the vibration reduction body of the rail transit train, k is the linear coefficient of the spring, β is the nonlinear coefficient of the spring, c is the viscous damping coefficient, Y(t) is the dry friction force when the wire mesh block slides, and x is the output displacement vector of the wire mesh floor vibration reduction system of the rail train; the force of the floor vibration reduction system is analyzed and the motion differential equation of the system is listed according to Newton's second law of motion: Where Y(t) = k s ·x s , x s is the deformation displacement vector when slip begins, k s is the linear stiffness before slip; P(t) is the load vector of the rail train vibration system, P(t)=[S(t),S u (t),F(t)], where S(t) is the track irregularity load input excitation, S u (t) is the load input excitation under the action of crosswind, and F(t) is the load input excitation of continuous walking.

[0119] Its mechanical model can be simplified as Figure 4 shown.

[0120] The present invention analyzes the static characteristics of the wire mesh floor damper through static compression test to understand the relationship between its static stiffness and damping change. Through micromechanics, it is found that the internal wire state process of the wire mesh block when loaded is divided into three stages: the free state when not in contact, the orthogonal sliding process when in contact, and the extrusion stage when parallel sliding.

[0121] The mechanical phenomena in these three different stages are manifested in the macroscopic characteristics of the wire mesh shock absorber during its operation: in the initial stage of loading, the shock absorber stiffness changes little, the deformation has linear elastic characteristics, and the stiffness value is very small, and a small load will cause a large change; with the continuous increase of load and displacement, its stiffness is also increasing, and the deformation shows a nonlinear gradual hardening stiffness characteristic; when the load increases to a certain extent, the stiffness reaches a limit value and then remains basically unchanged. Although the load is large, the deformation is very small, showing an exponential hardening characteristic. The specific test curve is as follows Figure 5 shown.

[0122] Experiments show that: the embodiment of the present invention combines the analysis of the working principle, characteristics and hysteresis loop of the wire mesh vibration absorber and the load characteristics of the rail train during operation, and designs a rectangular wire mesh vibration absorber with stiffness and damping characteristics that are compatible with the vibration load of the floor system in different degrees of freedom, and determines the stiffness and damping parameters of the wire mesh floor vibration absorber and its action structure. First, in the vertical direction of the train, due to the change in the passenger capacity in the car, the vibration excitation generated is also changing. When the rail transit vehicle is unloaded, the vibration excitation is small. At this time, the stiffness of the wire mesh floor damper changes little, and the deformation has linear elastic characteristics, which can meet its vibration reduction performance requirements; when the rail transit vehicle is half loaded, the mass of the overall vibration reduction equipment increases, so its vibration load also increases accordingly, the compression density of the wire mesh floor damper mesh block increases, and its stiffness also increases accordingly, so the ability of the damper to withstand the vibration load also adapts to the change in the mass of the vibration reduction equipment; and when the rail transit vehicle is fully loaded, the load increases to a certain extent, so that the wire mesh damper mesh block at this time presents a stiffness hard characteristic, that is, although it bears a large excitation load, the vibration response of the floor system is very small, and the vibration displacement is not severe. This static stiffness curve greatly adapts to the characteristics of the ever-changing passenger capacity of rail transit vehicles, so that the entire floor damping system can fully play its role under different road conditions and different passenger capacities. And because the damping system has variable stiffness (variable frequency) characteristics, it can adapt to the vibration control needs of trains under different load conditions, and also avoids the occurrence of resonance, which is also a protection for rail transit vehicles. In the running direction of the rail train, the rail transit vehicle needs to start, change speed and stop urgently due to the needs of operation or when some emergency situations occur. At this time, the floor system of the rail transit vehicle will be subject to a large lateral extrusion load, and under different passenger capacities, the size of this lateral extrusion load is obviously different. The lateral vibration load of the rail train is mainly caused by the turning of the train, and due to the relatively gentle characteristics of the wheel-rail turning of rail transit, the vibration load in this direction is small. Therefore, a rectangular wire mesh floor shock absorber is finally designed, so that its stiffness in the three degrees of freedom of the train vertical, lateral and running direction is different, which adapts to the characteristics of the vibration load of each degree of freedom of the floor shock absorption system of the rail transit vehicle, that is, the larger the vibration load, the larger the stiffness of the shock absorber in this degree of freedom. In addition, in order to meet the two-way vibration reduction on a single degree of freedom, the limit guide column 4 and the limit barrel 2 are designed in the shock absorber structure, so that the second wire mesh block 6 can withstand the vertical downward ballast load, and the first wire mesh block 3 can withstand the vertical upward tensile load, which solves the problem that the wire mesh block can only bear one-way load. In addition, the cooperation between the second metal wire mesh block 6 and other structures can be used to suppress the transverse reciprocating extrusion load of the train in the transverse direction and running direction of the train.In addition, compared with the previous metal wire mesh damper, the structure is more compact and does not require additional nested sealing rings, so the overall mass is reduced. Therefore, the size and weight of the invention can meet the lightweight requirements and installation space requirements for floor dampers in the field of rail transit. In terms of vibration noise control, the molding method of the metal wire mesh block determines that its internal structure is not dense, and its loose and porous metal structure can achieve the sound insulation and sound absorption effects of rail transit to a certain extent.

[0123] In the embodiment of the present invention, the specific process of the static compression test of the wire mesh vibration damper is as follows:

[0124] Since the vibration damping element of the wire mesh vibration damper is a wire mesh block, it is a metal rubber elastic component. Under the action of loading and unloading, residual deformation occurs inside the mesh block due to the elastic-plastic deformation of the wire turns and the relative slip and friction between the wires, making it impossible for the elastic restoring force of the mesh block to return to the initial state. Therefore, in order to reduce and eliminate the residual deformation inside the wire turns and stabilize the performance of the wire mesh material, before conducting a static compression test, the designed wire mesh vibration damper is subjected to 5 to 10 cycles of loading and unloading, and then cyclic loading and unloading is performed again in a decreasing deformation amplitude manner until the sensor signal outputs zero. In this way, the deformation zero point of the wire mesh block is found, and a static test can be carried out.

[0125] The test adopts the incremental load method or the standard universal testing machine loading method to detect the static load deformation of the wire mesh vibration absorber and obtain the load-displacement relationship curve. The static test system block diagram is as follows Figure 8 shown.

[0126] The test uses a universal testing machine with built-in displacement and pressure sensors to test the changes in pressure and displacement of the wire mesh shock absorber in the vertical direction under the working condition of 1mm / min. The wire mesh shock absorber is required to deform evenly during the load change process, and its loading speed is 1mm / min. Two static load forms under different working conditions are designed. First, the maximum rated load is set to 8KN. After gradually loading from 0 load to 8KN, it is kept for 30s and then gradually unloaded to 0 load, and its free static load and displacement values ​​in the vertical direction are recorded; then the wire mesh shock absorber is subjected to a second static test, and the maximum rated load is set to 12KN, but the load of 4KN is used as the starting and end point of loading and unloading, simulating the static load-displacement changes of the shock absorber under the condition of bearing the mass of the equipment. The test method is similar to the first time.

[0127] By processing the static test data of the wire mesh vibration absorber, the test displacement curves of the vibration absorber in the load range of 0-8KN and 4-12KN are obtained, as shown in Figure 9(a) and Figure 9(b) respectively.

[0128] From the static test of the wire mesh shock absorber, it can be known that the wire mesh shock absorber has nonlinear hysteresis characteristics of variable stiffness and variable damping. As the load increases, its stiffness becomes smaller and smaller, and the damping gradually increases; the slope of the test curve becomes more and more gentle, the hysteresis loop area will become flatter and larger, and the energy absorbed and dissipated will become more. Compared with the weight and height of the wire mesh shock absorber before and after the static test, there is no obvious change, the metal surface of the shock absorber has no deformation and cracks, the protective coating is evenly distributed and has no signs of damage, the wire mesh block has no fragmentation, broken wires, and no signs of serious deformation; indicating that the wire mesh block has good load-bearing and stability performance. In terms of static load-bearing and deformation, the structural design of the wire mesh shock absorber meets the actual engineering requirements of rail transit. In addition, the wire mesh vibration absorber has the characteristics of nonlinear gradual stiffness, which plays a good role in low-frequency vibration isolation and has a large load-bearing capacity; its internal mesh block acts as a vibration reduction and buffering element. The larger the hysteresis curve area, the greater the damping, and it can absorb more energy than linear elements. Therefore, it can effectively suppress the resonance peak and has excellent vibration reduction and buffering effects.

[0129] Example 4

[0130] like Figure 6 As shown, an embodiment of the present invention provides a simulation design system for a metal mesh vibration damper for rail transit, which runs on a client. The simulation design system for a metal mesh vibration damper for rail transit includes:

[0131] Model building module 7, used to build a mechanical model and a mathematical model of a wire mesh shock absorber for rail transportation;

[0132] Load excitation simulation module 8, used to simulate the excitation between the wheel rail and the track; the excitation of passengers on the vehicle; and the vibration excitation of external environmental factors;

[0133] The shock absorber overall structure acquisition module 9 is used to design the metal wire mesh shock absorber for rail transit based on the constructed mechanical model and mathematical model and the obtained load excitation information, including the design of the metal wire mesh stiffness and damping, and the design of the overall structure of the metal wire mesh shock absorber for rail transit;

[0134] The simulation experiment simulation module 10 is used to conduct simulation experiments based on the designed wire mesh vibration damper for rail transit to verify that the performance of the vibration damper meets the requirements of the rail transit floor vibration damping system, including: adaptive vibration damping effect in the three degrees of freedom of the train vertical, lateral and running direction; vibration damping effect under different passenger capacities; bidirectional vibration damping of a single degree of freedom; lightweight requirements; installation space requirements; vibration and noise control. The feasibility of the designed vibration damper is verified through the vibration damping test of the high-speed train wire mesh floor vibration damping system.

[0135] Example 5

[0136] In the embodiment of the present invention, the excitation between the wheel-rail and the track, the excitation of the passengers on the vehicle and the vibration excitation of the external environmental factors in step S2 specifically include the following contents:

[0137] Between wheel rail and track:

[0138] Track lines are the most important infrastructure in train operation. Their main function is to guide the train, bear the weight of the train structure and passengers transmitted by the wheel pairs, and transmit and disperse it to the roadbed. Track excitation usually refers to track unevenness excitation. Track unevenness usually refers to the actual deviation of the geometric dimensions of two parallel track lines from the ideal state. Track geometric unevenness is one of the external excitation factors that cause vibration during train operation. Track excitation causes vertical and lateral coupled vibrations of the train, which not only limits the safe speed of the train, but also affects the transportation volume and traffic volume of the railway line. Track unevenness excitation can be divided into the following four types, as shown in Figure 7 (a) for height unevenness; Figure 7 (b) for directional unevenness; Figure 7 (c) for horizontal unevenness and gauge unevenness.

[0139] The actual track irregularity excitation is composed of the superposition of simple harmonic vibrations with varying amplitudes, variable frequencies, and different phase angles. It is a random function that changes over the track mileage. By using mathematical statistics methods to collect and analyze a large amount of track irregularity data and perform curve fitting on the data, a track irregularity power spectrum suitable for railway lines is obtained, which is used as an external excitation input for train dynamics analysis to study the running quality of the train. Through comparative analysis of domestic and foreign track power spectra, the present invention uses the high and low irregularities of Germany's low-interference tracks as the track excitation analysis object and performs track spectrum time domain conversion. The present invention uses the inverse Fourier transform method to directly perform discrete sampling processing on the power spectrum density function to obtain the corresponding frequency spectrum, and then performs inverse Fourier transform processing on the sequence to calculate the track irregularity function in time domain form. The fitting formula for the train track irregularity power spectrum density is S(n)=A·n -k , through the formula And f = v·n, Δf = v·Δn, the function of power spectrum density with respect to spatial frequency n can be converted into a function with respect to temporal frequency f: S(f) = A·v k-1 ·f k The core idea of ​​the inverse Fourier transform method is to convert the single-sided spectrum into a double-sided spectrum according to the power spectrum density value. By performing an inverse Fourier transform on the double-sided spectrum, the simulated track irregularity time domain sequence can be obtained. After determining each parameter and converting the single-sided spectrum into the double-sided spectrum, the spectrum modulus value can be calculated from the conversion relationship between the spectrum modulus value and the power spectrum density value: X(k) is the Fourier transform of the track irregularity time-domain sequence x(k) to be simulated, and |X(k)| represents the amplitude of the harmonic with frequency f=k·Δf in the harmonic component of the time-domain sequence x(k). Through the above steps, the frequency and amplitude of each harmonic are known, but the initial phase is unknown. Due to the randomness of the time-domain sequence, the initial phase of each harmonic is It is regarded as a random variable that obeys a uniform distribution within 0 to 2π, so the expression of X(k) within the entire sampling frequency can be obtained as: Through the above method, the frequency, amplitude, and initial vibration phase of each harmonic can be obtained. The track irregularity function S(t) of the high-speed train is formed by superimposing each harmonic.

[0140] Vibration excitation from external environmental factors:

[0141] The vibration excitation of external environmental factors mainly considers the influence of air flow. Research on the aerodynamic performance of high-speed trains shows that the aerodynamic characteristics of trains will change under the action of strong side winds, including the aerodynamic lift, lateral force and overturning moment, which will affect the running stability and safety of the train. High-speed trains are very prone to accidents under the action of strong winds, threatening the lives and property safety of passengers.

[0142] The frequency domain characteristics of the fluctuating wind speed can be obtained through the wind speed power spectrum. The horizontal fluctuating wind speed power spectrum is described as follows: Among them, u * is the friction wind speed (shear wind speed); and is the average wind speed at height z, and n is the frequency of the wind (1 / s). In the formula, K is a dimensionless constant, K≈0.4; is the average height of surrounding buildings (m); Z0 is the ground roughness height (m). By performing inverse discrete Fourier transform on the wind speed power spectrum density function, we can obtain the pulsating wind time domain curve function S under different wind speeds, different heights, and different surrounding environments. u (t), the time domain curve function S u (t) is used as the load input excitation under crosswind action.

[0143] Encouragement for passengers on board:

[0144] Starting from the basic physical principles of human walking behavior, the continuous walking incentive of a person on a horizontal plane is analyzed. By summarizing the analysis of a person's single-step landing curve, the present invention finds that the center of gravity of a person is always rising and falling during walking, and the distance of up and down fluctuations is about 35mm for a person of average height. In fact, when a person walks, the force exerted on the ground is not always equal to the person's weight G, but a fluctuating value. At the moment when the sole of the foot touches the ground, this force is more or less greater than G. The step frequency f s It represents the number of steps a person takes per unit time and is another important parameter of the walking excitation time course. It determines the main frequency component of the walking excitation time course. Experimental studies have shown that the walking frequency f of an average person is s Around 1.9Hz. The stride is the distance a person takes in one step. When determining the number of steps a person needs to take to walk from point A to point B in a structure, the size of the stride needs to be considered. The size of the stride and the height of a person satisfy a simple proportional relationship dy=0.45H. Studies have found that the stride dy roughly follows a normal distribution with a mean of 0.71m and a variance of 0.071m. And when a person walks, there is a time period during which the left and right feet touch the ground at the same time. The overlapping time is related to the step frequency. The lower the step frequency, the longer the single-step landing curve lasts, and the longer the overlapping time dt is. Therefore, when using a single-step landing curve, it is necessary to clarify the actual step frequency f corresponding to the curve. s After knowing the single-step landing curve and its corresponding step frequency, the overlap time can be calculated according to To calculate, where t s represents the total duration of a single-step landing curve, f s Represents the step frequency. Assuming that the single-step landing curves generated by the left and right feet of a person are the same, the complete walking excitation force time history curve can be defined based on the single-step landing curve and the overlapping time. Considering the actual application, the influence of high-order simple harmonics can be ignored, and only the first-order simple harmonics that play the most role in the dynamic load are considered, and then the continuous walking excitation model of a person is simplified, and the load function of the simplified model is obtained as follows: F(t) = G[1+α1sin(2πf s t)], where G represents the average weight of a person, which is 0.7 kN; α1 represents the dynamic load factor of the first-order simple harmonic wave, which is 0.5; f s Indicates the step frequency, which is 1.9Hz.

[0145] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0146] Since the information interaction, execution process, etc. between the above-mentioned devices / units are based on the same concept as the method embodiment of the present invention, their specific functions and technical effects can be found in the method embodiment part and will not be repeated here.

[0147] Those skilled in the art can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example for illustration. In practical applications, the above-mentioned function allocation can be completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiment can be integrated into a processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of the present invention. The specific working process of the units and modules in the above-mentioned system can refer to the corresponding process in the aforementioned method embodiment, which will not be repeated here.

[0148] 2. Application examples:

[0149] Application Example 1

[0150] Application Example 1 of the present invention provides a wire mesh vibration damper, which can provide a vibration damping element for the high-speed train floor vibration damping system. The wire mesh vibration damper is installed at the bottom of the high-speed train compartment floor, and a floating floor is placed on the cover plate 5, and the bottom of the base 1 is connected to the frame structure of the compartment bottom; the floating floor uses an aluminum honeycomb floor or a cork floor, and the cover plate 5 is fixedly connected to the floating floor by bonding or bolts, thereby forming a bottom Fig.10 The high-speed train floor vibration reduction system shown.

[0151] The wire mesh damper floor vibration damping system was tested and its vibration damping performance test process was as follows: multiple wire mesh damper components were distributed on the floor of the high-speed train body, and the test system consisting of LMS data acquisition equipment, acceleration sensor, electromagnetic exciter and power amplifier was used to perform vibration transmission analysis. The layout diagram of the wire mesh floor damper is shown in Figure 11.

[0152] The excitation signal uses an electromagnetic exciter to excite the car body. The excitation condition uses single-frequency excitation, and the frequency distribution is: 5Hz, 10Hz, 12Hz, 15Hz, 20Hz, 25Hz, 30Hz, 32Hz, 34Hz, 36Hz, 38Hz, 40Hz, 42Hz, 44Hz, 46Hz, 48Hz, 50Hz, 52Hz, 54Hz, 56Hz, 58Hz, 60Hz, 65Hz, 70Hz, 75Hz, 80Hz. When arranging the measuring points, it is necessary to arrange the vibration measuring points inside and outside the car according to the arrangement of the equipment such as the traction transformer under the car and the arrangement of the elastic shock absorber on the floor inside the car. Arrange 8 vibration measuring points on the passenger compartment floor and 6 vibration measuring points on the body floor to capture the most complete vibration signal of the system with as few probes as possible. The actual test process is: after the excitation signal output by the electromagnetic exciter remains stable, collect the excitation force and the vibration acceleration signal of each measuring point at the same time, set the averaging method to linear averaging, and collect data 8 times. like Fig.12 is the test data of a certain measuring point.

[0153] The test results prove that the wire mesh floor vibration damper changes the overall stiffness and damping of the system, greatly reducing the efficiency of vibration signal transmission from the wheel rails on both sides to the middle floor, achieving a better vibration isolation effect.

[0154] Application Example 2

[0155] An application embodiment of the present invention also provides a computer device, which includes: at least one processor, a memory, and a computer program stored in the memory and executable on the at least one processor, wherein the processor implements the steps in the above-mentioned embodiment of the method for designing a wire mesh vibration damper for rail transit when executing the computer program.

[0156] Application Example 3

[0157] The application embodiment of the present invention further provides a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, it can implement the steps in the embodiment of the method for designing a wire mesh vibration damper for rail transit in the above embodiment.

[0158] Application Example 4

[0159] An embodiment of the present invention also provides an information data processing terminal, which is used to provide a user input interface to implement the steps in the embodiment of the metal mesh vibration damper design method for rail transit when executed on an electronic device. The information data processing terminal is not limited to mobile phones, computers, and switches.

[0160] Application Example 5

[0161] An application embodiment of the present invention provides a computer program product. When the computer program product runs on an electronic device, the electronic device can implement the steps in the above-mentioned method embodiments when executing the computer program product.

[0162] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the present invention implements all or part of the processes in the above-mentioned embodiment method, which can be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium. When the computer program is executed by the processor, the steps of the above-mentioned various method embodiments can be implemented. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may at least include: any entity or device that can carry the computer program code to the camera / terminal device, a recording medium, a computer memory, a read-only memory (ROM), a random access memory (RAM), an electrical carrier signal, a telecommunication signal, and a software distribution medium. For example, a USB flash drive, a mobile hard disk, a disk or an optical disk.

[0163] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any modifications, equivalent substitutions and improvements made by any technician familiar with the technical field within the technical scope disclosed by the present invention and within the spirit and principles of the present invention should be covered within the protection scope of the present invention.

Claims

1. A design method for a metal wire mesh vibration damper for rail transit, characterized in that: The design approach includes: S1, model establishment: construct the mechanical model and mathematical model of the shock absorber; S2, load excitation: excitation between wheel-rail and track, excitation of passengers on board, and vibration excitation of external environmental factors; S3, based on the mechanical model and mathematical model constructed in step S1 and the load excitation information obtained in step S2, designing the shock absorber, including the design of the stiffness and damping of the metal mesh, and the design of the overall structure of the shock absorber; S4, based on the shock absorber designed in step S3, a simulation experiment is performed to verify that the shock absorber performance meets the requirements of the rail transit floor vibration reduction system, and the feasibility of the designed shock absorber is verified by a vibration reduction test of the high-speed train metal mesh floor vibration reduction system; The metal wire mesh vibration damper for rail transit uses a limit barrel (2) and a limit guide column (4) to cooperate with each other to suppress the vertical reciprocating load excitation of the metal wire mesh block when the rail transit vehicle is actually running, so as to meet the requirements of buffering the lateral reciprocating vibration of the rail transit vehicle during steering, starting and emergency stopping; The different stiffness of the wire mesh blocks in different degrees of freedom are used to reduce the vibration response of rail vehicles in different degrees of freedom. The variable stiffness characteristics of the wire mesh blocks are used to adapt to the vibration control requirements of trains under different load conditions and eliminate resonance. In step S1, constructing a mechanical model of the shock absorber includes: Assume that m is the mass of the vibration reduction body of the rail transit train, k is the linear coefficient of the spring, β is the nonlinear coefficient of the spring, c is the viscous damping coefficient, Y(t) is the dry friction force when the wire mesh block slides, and x is the output displacement vector of the wire mesh floor vibration reduction system of the rail train; analyze the force of the floor vibration reduction system and list the motion differential equation of the system according to Newton's second law of motion: Where Y(t) = k s ·x s , x s is the deformation displacement vector when slip begins, k s is the linear stiffness before slip; P(t) is the load vector of the rail train vibration system, P(t) = [S(t), S u (t), F(t)], where S(t) is the track irregularity load input excitation, S u (t) is the load input excitation under the action of crosswind, and F(t) is the load input excitation of continuous walking.

2. The design method of the metal mesh vibration damper for rail transit according to claim 1, characterized in that: The metal wire mesh block is made of stainless steel metal wire material.

3. The design method of the metal wire mesh vibration damper for rail transit according to claim 1, characterized in that: Also includes: A base (1), a cover plate (5), wherein the metal wire mesh block comprises: a first metal wire mesh block (3) and a second metal wire mesh block (6); There are two limit barrels (2), and the two limit barrels (2) are installed on two symmetrical holes in the base (1); a second metal wire mesh block (6) is placed in the base (1), and the upper part of the second metal wire mesh block (6) is covered with a cover plate (5); first metal wire mesh blocks (3) are placed on the left and right sides of the limit barrel (2), and the first metal wire mesh block (3) is limited in the limit barrel (2) by a limit guide column (4); there are two limit guide columns (4); the two limit guide columns (4) pass through the two first metal wire mesh blocks (3) and the limit barrel (2) from the bottom respectively, and the cover plate (5) is connected to the two limit guide columns (4) by riveting.

4. The design method of the metal mesh vibration damper for rail transit according to claim 3, characterized in that: The two threaded holes on the two wings of the base (1) and the three threaded holes on the cover plate (5) are used for connection with the main body of the external equipment; The shock absorber is installed at the bottom of the carriage floor, a floating floor is placed on the cover plate (5), and the bottom of the base (1) is connected to the frame structure of the carriage bottom; The floating floor uses an aluminum honeycomb floor or a cork floor, and the cover plate (5) is fixedly connected to the floating floor by bonding or bolts; the base (1), the cover plate (5), the limit barrel (2) and the limit guide column (4) are all made of metal materials through mechanical processing, and the stainless steel wire used in the first metal wire mesh block (3) and the second metal wire mesh block (6) is made through wire selection, wire winding, stretching, weaving and molding processes.

5. The design method of the metal wire mesh vibration damper for rail transit according to claim 1, characterized in that: In step S2, the excitation between the wheel-rail and the track, the excitation of passengers on the vehicle, and the vibration excitation of external environmental factors include: When rail vehicles are in operation, the vibration excitation from the unevenness between the wheel-rail and the track, the vibration excitation from the movement of passengers in the car and the vibration excitation from external environmental factors will transfer the vibration of the train to the floor vibration damping system. The wire mesh floor vibration damper consumes and stores the energy generated by the vibration of the car body through the elastic strain, extrusion and friction slip between the internal wire meshes. During the vertical vibration of the vehicle body, the structure in which the limit barrel (2) and the limit guide column (4) cooperate enables the first metal wire mesh block (3) and the second metal wire mesh block (6) to act alternately, the first metal wire mesh block (3) being used to withstand upward tensile excitation, thereby reducing the vibration response of the tensile excitation; the second metal wire mesh block (6) being used to withstand downward ballast excitation, thereby reducing the vibration response of the ballast excitation; When the train turns, starts or stops suddenly, the second metal wire mesh block (6) bears the reciprocating extrusion effect of the lateral vibration load, and the base (1), the cover plate (5), the limit barrel (2) and the limit guide column (4) cooperate to suppress the vibration excitation load generated when the train starts, changes speed and stops suddenly, and buffer the lateral vibration load generated when the train turns.

6. The design method of the metal wire mesh vibration damper for rail transit according to claim 1, characterized in that: The wheel-rail-track excitation specifically includes: taking the low-interference track height irregularity as the track excitation analysis object, and performing track spectrum time domain conversion: using the inverse Fourier transform method to directly perform discrete sampling processing on the power spectrum density function to obtain the corresponding spectrum, and then performing inverse Fourier transform processing on the spectrum sequence to calculate the track irregularity function in the time domain form; The fitting formula of the power spectrum density of train track irregularity is S(n) = A·n -k , through the formula And f = v·n, Δf = v·Δn, convert the function of power spectral density with respect to spatial frequency n into a function with respect to temporal frequency f: S(f) = A·v k-1 ·f k ; After determining each parameter and converting the single-sided spectrum to the double-sided spectrum, the spectrum modulus value is calculated from the conversion relationship between the spectrum modulus value and the power spectrum density value: X(k) is the Fourier transform of the track irregularity time-domain sequence x(k) to be simulated, and |X(k)| represents the amplitude of the harmonic with frequency f=k·Δf in the harmonic component of the time-domain sequence x(k); The frequency and amplitude of each harmonic are known, but the initial phase is unknown. As a random variable that obeys uniform distribution within 0~2π, the expression of X(k) within the entire sampling frequency is obtained as: The frequency, amplitude, and initial vibration phase of each harmonic are obtained. The track irregularity function S(t) of the high-speed train is formed by superimposing each harmonic. The motivation of passengers on the bus includes: based on the basic physical principles of human walking behavior, after knowing the single-step landing curve and the corresponding step frequency, the overlap time is calculated according to Calculate, where t s represents the total duration of a single-step landing curve, f s represents the step frequency; ignoring the influence of high-order simple harmonics, only combining the first-order simple harmonics in the dynamic load, simplifying the human continuous walking excitation model, and obtaining the load function of the simplified model: F(t) = G[1+α1sin(2πf s t)], where G represents the average weight of a person, which is 0.7 kN; α1 represents the dynamic load factor of the first-order simple harmonic wave, which is 0.5; f s Indicates the step frequency, which is 1.9Hz; The load excitation in step S2 also includes: vibration excitation of external environmental factors: The frequency domain characteristics of the fluctuating wind speed are obtained through the wind speed power spectrum. The horizontal fluctuating wind speed power spectrum is described as follows: Among them, u * is the frictional wind speed; and is the average wind speed at height z, n is the frequency of the wind (1 / s); In the formula, K is a dimensionless constant, K=0.4; is the average height of the surrounding buildings, in meters, and Z0 is the ground roughness height, in meters; by performing inverse discrete Fourier transform on the wind speed power spectrum density function, we can obtain the pulsating wind time domain curve function S under different wind speeds, different heights, and different surrounding environments. u (t), the time domain curve function S u (t) is used as the load input excitation under crosswind action.

7. The design method of the metal wire mesh vibration damper for rail transit according to claim 1, characterized in that: In step S4, the simulation experiment includes: adaptive vibration reduction effect in three degrees of freedom of the train: vertical, lateral and running direction; vibration reduction effect under different passenger capacities; bidirectional vibration reduction of a single degree of freedom; lightweight requirements; installation space requirements; vibration and noise control; and the feasibility of the designed shock absorber is verified through the vibration reduction test of the high-speed train metal mesh floor vibration reduction system.

8. A simulation design system for implementing the design method of the metal mesh vibration damper for rail transit according to claim 1, characterized in that: Running on the client, the simulation design system includes: A model building module (7), used for building a mechanical model and a mathematical model of the shock absorber; A load excitation simulation module (8) is used to simulate the excitation between the wheel rail and the track, the excitation of passengers on the vehicle, and the vibration excitation of external environmental factors; A shock absorber overall structure acquisition module (9), which is used to design the shock absorber based on the constructed mechanical model and mathematical model and the obtained load excitation information, including the design of the stiffness and damping of the metal mesh and the design of the overall structure of the shock absorber; The simulation experiment simulation module (10) is used to conduct simulation experiments based on the designed shock absorber to determine whether the shock absorber performance meets the requirements of the rail transit floor shock absorption system, including: adaptive shock absorption effects in the three degrees of freedom of the train vertical, lateral and running directions, shock absorption effects under different passenger capacities, bidirectional shock absorption of a single degree of freedom, lightweight requirements, installation space requirements, and vibration and noise control; and verify the feasibility of the designed shock absorber through a high-speed train metal mesh floor shock absorption system shock absorption test.

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