Ballast track bed composite elastic sleeper cushion structure and modeling method thereof

Abstract

The invention relates to a ballast track bed composite elastic sleeper cushion structure and a modeling method thereof, and belongs to the technical field of vibration and noise reduction of rail transit. The composite elastic sleeper cushion structure of the ballast track bed comprises lower-layer rubber, a first single-side trapezoidal steel plate, a middle rubber layer, a second single-side trapezoidal steel plate and upper-layer rubber, by ingeniously designing the middle rubber layer between the two single-side trapezoidal steel plates and combining the upper rubber layer and the lower rubber layer, the formed ballast track bed composite elastic sleeper pad can effectively enhance wear resistance, durability and deformation resistance and prolong the service life, and the invention further provides a modeling method of the ballast track bed composite elastic sleeper pad structure. A selectable method is provided for simulation calculation of the composite elastic sleeper cushion of the ballast track bed by setting material parameters of each component, setting boundary conditions, dividing grids, carrying out a mechanical loading experiment, endowing actual working condition loads and extracting required data for processing and analysis.

Description

Technical Field

[0001] The invention relates to a composite elastic sleeper pad structure of a ballasted track bed and a modeling method thereof, and belongs to the technical field of vibration reduction and noise reduction in rail transit. Background Art

[0002] The ballasted track is a complete mechanical system consisting of trains, rails, sleepers, fasteners, ballast layers, and subgrade layers. The ballasted track bed refers to a track structure formed by the accumulation of crushed stone particles under the rails according to a certain gradation, density, and shape. The structure has typical looseness, combination, and state dependence. It has the advantages of low engineering cost, good vibration and noise reduction performance, convenient maintenance, and good drainage performance. In the ballasted track bed, the rails are located above the sleepers, and the sleepers are in direct contact with the loose ballast particles.

[0003] In recent years, with the high speed and heavy load of trains, the ballasted trackbed is prone to ballast particles being crushed and pulverized under the action of severe dynamic impact force, which intensifies the wear of the edges and corners of the ballast particles and reduces the interlocking ability of the ballast particles, thereby accelerating the settlement and compaction of the ballast layer of the ballasted trackbed, reducing the elasticity and drainage performance of the ballasted trackbed, and affecting driving safety. According to existing research, the use of elastic sleeper pads in ballasted trackbeds can effectively improve the contact state between sleepers and ballast, reduce the crushing of ballast particles, reduce the vibration impact on the trackbed and the lower foundation, and prolong the service life of the trackbed. However, the existing elastic sleeper pads are mainly made of a single rubber material or a single polyurethane material. They have average wear resistance, durability, and deformation resistance, and a short service life. In addition, the rubber pads are easily scratched by the direct contact between the rubber pads and the edges and corners of the ballast. Therefore, there is an urgent need for a sleeper pad that has long service life, is wear-resistant, durable, has strong deformation resistance, and is not easily punctured by sharp corners of ballast. Summary of the invention

[0004] The present invention provides a composite elastic sleeper pad structure for a ballasted track bed, which forms a novel composite elastic sleeper pad structure for a ballasted track bed by cleverly designing an intermediate rubber layer between two single-sided trapezoidal steel plates and combining the upper and lower rubber layers. A modeling method for the composite elastic sleeper pad structure for a ballasted track bed is further provided, thereby providing an optional method for simulation calculation of the composite elastic sleeper pad for a ballasted track bed.

[0005] The technical solution of the present invention is:

[0006] According to a first aspect of the present invention, a composite elastic sleeper pad structure for a ballast track bed is provided, comprising: a lower rubber layer 1; a first single-sided trapezoidal steel plate 2-1, one side of the first single-sided trapezoidal steel plate 2-1 is a plane, and the other side of the first single-sided trapezoidal steel plate 2-1 is provided with grooves arranged at intervals and the concave direction of the grooves is toward the lower rubber layer 1; one side of the plane of the first single-sided trapezoidal steel plate 2-1 is bonded to the upper surface of the lower rubber layer 1; an intermediate rubber layer 3, the intermediate rubber layer 3 is provided with convex Platform, one side of the boss of the middle rubber layer 3 is fixed with one side of the groove of the first single-sided trapezoidal steel plate 2-1 in shape; second single-sided trapezoidal steel plate 2-2, the second single-sided trapezoidal steel plate 2-2 has the same structure as the first single-sided trapezoidal steel plate 2-1; one side of the groove of the second single-sided trapezoidal steel plate 2-2 is fixed with the other side of the boss of the middle rubber layer 3 in shape; upper layer rubber 4, the upper layer rubber 4 has the same structure as the lower layer rubber 1; the lower surface of the upper layer rubber 4 is bonded to one side of the plane of the second single-sided trapezoidal steel plate 2-2.

[0007] Furthermore, the lower rubber layer 1, the first single-sided trapezoidal steel plate 2-1, the middle rubber layer 3, the second single-sided trapezoidal steel plate 2-2, and the upper rubber layer 4 form a square structure as a whole, having two oppositely arranged first surfaces, two oppositely arranged second surfaces, and two oppositely arranged third surfaces, the first surfaces, the second surfaces, and the third surfaces are perpendicular to each other, and the lower surface of the lower rubber layer 1 and the upper surface of the upper rubber layer 4 are two oppositely arranged first surfaces.

[0008] Furthermore, a protective layer of rubber 5 is bonded to the second surface and the third surface.

[0009] Furthermore, a non-woven anti-puncture layer is bonded to the lower surface of the lower rubber layer 1 .

[0010] Furthermore, the boss corners formed by adjacent trapezoidal grooves on one side of the grooves of the first single-sided trapezoidal steel plate 2-1 and the second single-sided trapezoidal steel plate 2-2 are chamfered; the groove corners formed by adjacent bosses on both sides of the middle rubber layer 3 are chamfered.

[0011] Furthermore, the grooves of the first single-sided trapezoidal steel plate 2-1 and the second single-sided trapezoidal steel plate 2-2 are isosceles trapezoidal grooves, and the bosses on both sides of the middle rubber layer 3 are isosceles trapezoidal bosses.

[0012] According to a second aspect of the present invention, a modeling method for a composite elastic sleeper pad structure of a ballasted track bed is provided, comprising the following steps: establishing a three-dimensional structural model of each component of the composite elastic sleeper pad of the ballasted track bed; importing the three-dimensional structural model of each component into finite element software, and loading them using a first / second loading method; wherein the first loading method is loading a displacement load, and the second loading method is loading a concentrated force load based on actual train operating conditions.

[0013] Furthermore, the three-dimensional structural models of each component are imported into the finite element software and loaded using the first / second loading method, including:

[0014] S1. Import the three-dimensional structural models of each component into the finite element software and assemble them to obtain the composite elastic sleeper pad assembly model of the ballasted track bed;

[0015] S2. Setting the density, Young's modulus, yield stress and Poisson's ratio parameters of the first single-sided trapezoidal steel plate 2-1 and the second single-sided trapezoidal steel plate 2-2 in the composite elastic sleeper pad assembly model of the ballasted track bed;

[0016] S3, setting the density and mechanical property parameters of the lower rubber layer 1, the middle rubber layer 3, and the upper rubber layer 4 in the composite elastic sleeper pad assembly model of the ballast track bed, selecting the material type of the rubber as isotropic, and the constitutive model of the rubber material as Mooney-Rivlin;

[0017] S4, setting a reference point RP1 at the center of the lower surface of the lower rubber layer 1, and setting a reference point RP2 at the center of the upper surface of the upper rubber layer 4;

[0018] S5, create analysis step: first select the dynamic display type; then set the simulation time; finally, in the output request manager, select to output the mechanical parameters at the upper surface reference point RP2 of the upper rubber 4;

[0019] S6. Setting contact parameters: adopt binding contact between the lower rubber layer 1 and the first single-sided trapezoidal steel plate 2-1, the first single-sided trapezoidal steel plate 2-1 and the middle rubber layer 3, the middle rubber layer 3 and the second single-sided trapezoidal steel plate 2-2, and the second single-sided trapezoidal steel plate 2-2 and the upper rubber layer 4; and couple the lower surface of the lower rubber layer 1 with the reference point RP1, and couple the upper surface of the upper rubber layer 4 with the reference point RP2;

[0020] S7. In the loading module, set the loading boundary conditions: the bottom surface of the lower rubber layer 1 is fixed;

[0021] S8, applying a linearly increasing displacement load at the reference point RP2 of the upper surface of the upper rubber layer 4 or applying a concentrated force load according to the actual train working condition;

[0022] S9. In the mesh division module, mesh the lower rubber layer 1, the first single-sided trapezoidal steel plate 2-1, the middle rubber layer 3, the second single-sided trapezoidal steel plate 2-2, and the upper rubber layer 4, and submit them for calculation, and analyze the mechanical properties of the elastic sleeper pad based on the calculation results.

[0023] The beneficial effects of the present invention are:

[0024] 1. The present invention establishes an elastic sleeper pad made of non-single rubber material, and adopts an alternating combination of steel plates and rubber materials, which effectively enhances the wear resistance, durability, deformation resistance and service life of the elastic sleeper pad, and a non-woven fabric anti-puncture layer is bonded to the bottom of the lower rubber layer, which can effectively prevent the edges and corners of the ballast from directly scratching the sleeper pad. In addition, the protective layer rubber of the elastic sleeper pad can prevent rainwater from entering the interior of the elastic sleeper pad, further extending the service life of the sleeper pad.

[0025] 2. In the present invention, the elastic sleeper pad is made of steel plate and rubber material vulcanized and bonded. One side of the steel plate is flat and the other side has a trapezoidal structural groove, which effectively increases the contact area between the rubber material and the single-sided trapezoidal steel plate. In addition, since the steel plate is tightly bonded to the rubber layer, when the elastic sleeper pad is subjected to vertical load, the deformation of the rubber layer is constrained by the steel plate, so that the elastic sleeper pad has a large vertical bearing capacity and vertical stiffness. At the same time, the trapezoidal protrusion of the single-sided trapezoidal steel plate can effectively reduce the horizontal deformation of the middle layer rubber while ensuring the horizontal flexibility of the middle layer rubber.

[0026] 3. In the present invention, a modeling method for a composite elastic sleeper pad structure on a ballasted track bed is proposed. First, a structural model of the elastic sleeper pad is established. Further, it is imported into finite element software for assembly, material parameters of each component are set, boundary conditions are set, grids are divided, and mechanical loading experiments are carried out. At the same time, actual working loads are assigned, and required data are extracted for processing and analysis. This method provides a new approach to numerical simulation calculations of elastic sleeper pads on ballasted track beds. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a flow chart of the present invention;

[0028] Figure 2 It is a half-section schematic diagram of the composite elastic sleeper pad structure of the ballasted track bed of the present invention;

[0029] Figure 3 It is a schematic diagram of the appearance of the composite elastic sleeper pad structure of the ballast track bed of the present invention (the protective layer rubber is not shown in the figure);

[0030] Figure 4 It is a schematic diagram of the structure of a single-side trapezoidal steel plate of the present invention;

[0031] Figure 5Schematic diagram of the structure of the intermediate layer rubber of the present invention;

[0032] Figure 6 It is a schematic diagram of the influence of steel plate structures of different shapes on the mechanics of the sleeper pad discussed in the present invention;

[0033] Figure 7 It is a mechanical schematic diagram of the elastic sleeper pad and the single rubber material sleeper pad of the present invention;

[0034] Figure 8 It is a schematic diagram of the influence of the upper bottom width f of the trapezoidal groove of the single-sided trapezoidal steel plate discussed in the present invention on the mechanics of the sleeper pad;

[0035] Fig. 9 It is a schematic diagram of the influence of the vertex angle θ on the mechanics of the sleeper pad discussed in the present invention;

[0036] Fig.10 Schematic diagram of the effect of the minimum thickness e of the first single-sided trapezoidal steel plate on the mechanics of the sleeper pad;

[0037] Fig.11 Schematic diagram of the influence of maximum thickness d on the mechanics of the sleeper pad;

[0038] Fig.12 is a schematic diagram of actual train load applied by the present invention;

[0039] Fig.13 It is a schematic diagram of the displacement of the sleeper pad corresponding to the actual train load applied to the present invention;

[0040] The numbers in the figure are: 1-lower layer rubber, 2-1-first single-sided trapezoidal steel plate, 3-middle rubber layer, 2-2-second single-sided trapezoidal steel plate, 4-upper layer rubber, 5-protective layer rubber. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. It should be noted that the embodiments in this application and the features in the embodiments can be combined with each other arbitrarily without conflict.

[0042] Example 1: Figure 1-13As shown, according to a first aspect of an embodiment of the present invention, a composite elastic sleeper pad structure with a ballasted track bed is provided, which is used for laying under the sleepers in the area to be reinforced, and the composite elastic sleeper pad structure with a ballasted track bed comprises: a lower rubber layer 1, a first single-sided trapezoidal steel plate 2-1, an intermediate rubber layer 3, a second single-sided trapezoidal steel plate 2-2, and an upper rubber layer 4; one side of the first single-sided trapezoidal steel plate 2-1 is a plane, and the other side of the first single-sided trapezoidal steel plate 2-1 is provided with grooves arranged at intervals and the concave direction of the grooves is toward the lower rubber layer 1; one side of the plane of the first single-sided trapezoidal steel plate 2-1 is in contact with the The upper surface of the lower rubber layer 1 is bonded; the middle rubber layer 3 is provided with a boss extending from the middle to both sides, and one side of the boss of the middle rubber layer 3 is bonded and fixed with a shape matching one side of the groove of the first single-sided trapezoidal steel plate 2-1; the second single-sided trapezoidal steel plate 2-2 has the same structure as the first single-sided trapezoidal steel plate 2-1; one side of the groove of the second single-sided trapezoidal steel plate 2-2 is bonded and fixed with a shape matching the other side of the boss of the middle rubber layer 3; the upper rubber layer 4 has the same structure as the lower rubber layer 1; the lower surface of the upper rubber layer 4 is bonded to one side of the plane of the second single-sided trapezoidal steel plate 2-2.

[0043] Furthermore, the lower rubber layer 1, the first single-sided trapezoidal steel plate 2-1, the middle rubber layer 3, the second single-sided trapezoidal steel plate 2-2, and the upper rubber layer 4 form a square structure as a whole, having two oppositely arranged first surfaces, two oppositely arranged second surfaces, and two oppositely arranged third surfaces, the first surfaces, the second surfaces, and the third surfaces are perpendicular to each other, and the lower surface of the lower rubber layer 1 and the upper surface of the upper rubber layer 4 are two oppositely arranged first surfaces.

[0044] Furthermore, the second surface and the third surface are bonded with a protective layer of rubber 5. That is, the protective layer of rubber 5, the upper layer of rubber 4, and the lower layer of rubber 1 seal the internal structure together, thereby achieving the purpose of extending the service life of the elastic sleeper pad.

[0045] Furthermore, the lower rubber layer 1, the first single-sided trapezoidal steel plate 2-1, the middle rubber layer 3, the second single-sided trapezoidal steel plate 2-2, the upper rubber layer 4, and the protective rubber layer 5 are bonded by high-temperature vulcanization.

[0046] Furthermore, a non-woven anti-puncture layer is bonded to the lower surface of the lower rubber layer 1. Based on this design, the ballast can be prevented from puncturing the lower rubber layer, thereby increasing the service life of the elastic sleeper pad.

[0047] Furthermore, the grooves of the first single-sided trapezoidal steel plate 2-1 and the second single-sided trapezoidal steel plate 2-2 are isosceles trapezoidal grooves, and the bosses on both sides of the middle rubber layer 3 are isosceles trapezoidal bosses.

[0048] Preferably, the first and second unilateral trapezoidal steel plates have the same structure and are arranged relative to each other. The first unilateral trapezoidal steel plate is further described as follows: one side of the first unilateral trapezoidal steel plate is a plane, and the other side is an isosceles trapezoidal groove structure arranged at intervals. The width f of the upper bottom side of the trapezoidal groove is 40 mm, and the top angle θ is 120°. The minimum thickness e of the first unilateral trapezoidal steel plate is 4 mm, and the maximum thickness d is 8 mm. The corners of the bosses formed by the adjacent trapezoidal grooves of the first unilateral trapezoidal steel plate are rounded (i.e. Figure 4 The design can effectively prevent sharp corners from scratching the rubber material. The trapezoidal groove structure of the single-sided trapezoidal steel plate of the present invention can effectively increase the contact area between the first and second single-sided trapezoidal steel plates and the middle rubber layer, further increase the bonding area, and effectively prevent the middle rubber layer 3 from moving along the length direction of the elastic rail sleeper pad. The corners of the grooves formed by the adjacent bosses on both sides of the middle rubber layer 3 are rounded (i.e. Figure 5 The minimum thickness h of the intermediate rubber layer 3 is 4 mm, and the maximum thickness g is 8 mm.

[0049] In order to verify the performance of the "ballasted track bed composite elastic sleeper pad structure" of the present invention, the present invention is compared with the other two methods:

[0050] The first comparative scheme is different from the present invention in that: the first single-sided trapezoidal steel plate 2-1 and the second single-sided trapezoidal steel plate 2-2 of the present invention are replaced by flat plates, and the middle rubber layer 3 is correspondingly set as a square body;

[0051] The second comparative scheme is different from the present invention in that the first single-sided trapezoidal steel plate 2-1 and the second single-sided trapezoidal steel plate 2-2 of the present invention are replaced by single-sided rectangular plates, and the boss of the middle rubber layer 3 is correspondingly set to a rectangle.

[0052] The composite elastic sleeper pad samples with a=100mm, b=100mm, c=32mm in the present invention and the first and second comparative schemes are subjected to displacement load loading (the cross-sectional areas of the corresponding components are the same in the three schemes), and the force-displacement curves obtained are as follows: Figure 6 As shown, Figure 6 The "flat plate" is the first comparative solution, the "single-sided rectangular plate" is the second comparative solution, and the "single-sided trapezoidal plate" is the present invention. Figure 6 It can be seen that the present invention has higher strength and rigidity than other similar methods by cleverly designing the connection between the single-side trapezoidal plate and the middle rubber layer and the upper and lower rubber layers. Wherein, a represents the width of the composite elastic sleeper pad, b represents the length of the composite elastic sleeper pad, and c represents the thickness of the composite elastic sleeper pad.

[0053] Furthermore, the present invention is compared with the scheme using only the rubber layer. The composite elastic sleeper pad samples with a=100mm, b=100mm, and c=32mm under the present invention and the scheme using only the rubber layer are subjected to displacement load loading. The force-displacement curves obtained are as follows: Figure 7 As shown, Figure 7 The "rubber + Q235" in the figure is the solution of the present invention, and the "rubber" is the solution using only the rubber layer. Figure 7 It can be seen that the present invention cleverly designs the connection between the single-sided trapezoidal plate and the middle rubber layer and the upper and lower rubber layers. Compared with the solution using only the rubber layer, the strength and rigidity of the present invention are significantly higher than the comparative solution.

[0054] According to a second aspect of an embodiment of the present invention, a modeling method for a composite elastic sleeper pad structure of a ballasted track bed is provided, comprising the following steps: establishing a three-dimensional structural model of each component of the composite elastic sleeper pad of the ballasted track bed; importing the three-dimensional structural model of each component into finite element software, and loading them using a first / second loading method; wherein the first loading method is loading a displacement load, and the second loading method is loading a concentrated force load based on actual train operating conditions.

[0055] Furthermore, the three-dimensional structural models of each component are imported into the finite element software and loaded using the first / second loading method, including:

[0056] S1. Import the three-dimensional structural models of each component into the finite element software and assemble them to obtain the composite elastic sleeper pad assembly model of the ballasted track bed;

[0057] S2. Setting the density, Young's modulus, yield stress and Poisson's ratio parameters of the first single-sided trapezoidal steel plate 2-1 and the second single-sided trapezoidal steel plate 2-2 in the composite elastic sleeper pad assembly model of the ballasted track bed;

[0058] S3. Set the density and mechanical property parameters of the lower rubber layer 1, the middle rubber layer 3 and the upper rubber layer 4 in the composite elastic sleeper pad assembly model of the ballast track bed. Select the material type of the rubber as isotropic and the constitutive model of the rubber material as Mooney-Rivlin. The Mooney-Rivlin constitutive model can better describe the hyperelastic properties of the rubber material at small and medium strains. The strain energy density function expression is:

[0059] W=C 10 (I 1 -3)+C 01 (I 2 -3);

[0060] In the formula, C 10 , C 01 Represents the mechanical property constant of rubber material, I 1 ,I 2represents the deformation tensor invariant;

[0061] S4, setting a reference point RP1 at the center of the lower surface of the lower rubber layer 1, and setting a reference point RP2 at the center of the upper surface of the upper rubber layer 4;

[0062] S5. In the Create step, select the Dynamic / Explicit type, set the simulation time (Timeperiod), and in the History OutputRequest manager, select to output the mechanical parameters such as force, displacement, stress and strain at the upper surface reference point RP2 of the upper rubber 4;

[0063] S6. Setting the contact parameters (Interaction), the lower rubber layer 1 and the first single-sided trapezoidal steel plate 2-1, the first single-sided trapezoidal steel plate 2-1 and the middle rubber layer 3, the middle rubber layer 3 and the second single-sided trapezoidal steel plate 2-2, the second single-sided trapezoidal steel plate 2-2 and the upper rubber layer 4 adopt binding (Tie) contact, and the lower surface of the lower rubber layer 1 is coupled with the reference point RP1, and the upper surface of the upper rubber layer 4 is coupled with the reference point RP2; It can be seen from the application of the above technical scheme that compared with the general contact, only the surface contact can be simply defined, and the mutual bonding effect between the single-sided trapezoidal steel plate and the rubber in the composite elastic sleeper pad cannot be simulated; and the rubber and the single-sided trapezoidal steel plate in the present invention adopt (Tie) binding contact, which can ensure the tight connection between the rubber and the steel plate of the composite elastic sleeper pad without relative slippage and separation, and can more realistically simulate the bonding performance of the composite elastic sleeper pad using the vulcanization process in reality;

[0064] S7. In the Load module, set the loading boundary condition, fix the bottom surface of the lower rubber layer 1, apply a linearly increasing displacement load at the reference point RP2 of the upper surface of the upper rubber layer 4, or apply a concentrated force load according to the actual train working condition;

[0065] S8. In the Mesh module, mesh the lower rubber layer 1, the first single-sided trapezoidal steel plate 2-1, the middle rubber layer 3, the second single-sided trapezoidal steel plate 2-2, and the upper rubber layer 4 using C3D8R, and submit the calculations. Analyze the mechanical properties of the elastic sleeper pad based on the calculation results.

[0066] In the above, the actual train working condition is specifically: applying the actual load of the train according to the "Discrete Element-Flexible Body Coupling Analysis of Ballast-Soft Pillow Interaction".

[0067] Exemplarily, the optional specific implementations of the two loading methods are described as follows:

[0068] 1. The first loading method of composite elastic sleeper pad on ballasted track bed - loading displacement load

[0069] The overall dimensions of the composite elastic sleeper pad are as follows: Figure 3 As shown, a = 320mm, b = 2600mm, c = 32mm. In order to improve the calculation efficiency of the composite elastic sleeper pad in the finite element software and save time cost, the composite elastic sleeper pad samples with a = 100mm, b = 100mm, c = 32mm were loaded with displacement loads. The mechanical effects of the upper bottom width f (10mm, 20mm, 30mm, 40mm, 50mm) of the trapezoidal groove of the five single-sided trapezoidal steel plates, the three vertex angles θ (90°, 120°, 150°), the minimum thickness e (3mm, 4mm, 5mm) and the maximum thickness d (8mm, 9mm, 10mm) of the single-sided trapezoidal steel plate on the composite elastic sleeper pad were discussed. The test plan is shown in Table 1, and the experimental results are shown in Table 1. Figure 8-11 As shown. Figure 8-11 It can be seen that the upper bottom width f and the top angle θ of the trapezoidal groove of the single-sided trapezoidal steel plate have little effect on the stiffness of the composite elastic sleeper pad, and the minimum thickness e and maximum thickness d of the single-sided trapezoidal steel plate have a significant effect on the stiffness of the composite elastic sleeper pad. Taking the stiffness of the sleeper pad as 80kN / mm as the standard for measuring the composite elastic sleeper pad, the present invention selects the upper bottom width f=40mm of the trapezoidal groove of the single-sided trapezoidal steel plate, the top angle θ=120°, the minimum thickness e=4mm of the single-sided trapezoidal steel plate, and the maximum thickness d=8mm of the single-sided trapezoidal steel plate; the above selected parameters are consistent with the conclusion of the existing document "Analysis of mesoscopic mechanical dynamic characteristics of ballast bed with under sleeper pads" that "the vibration reduction effect of the sleeper pad is better when the stiffness of the sleeper pad is 80kN / mm".

[0070] Table 1 Experimental scheme of composite elastic sleeper pad

[0071]

[0072] The modeling steps using the first loading method are as follows:

[0073] S1. Import the three-dimensional structural models of each component into the finite element software and assemble them to obtain the composite elastic sleeper pad assembly model of the ballast track bed, such as Figure 3 As shown; the specific assembly sequence is: from bottom to top, assemble in the order of lower rubber layer 1, first single-sided trapezoidal steel plate 2-1, middle rubber layer 3, second single-sided trapezoidal steel plate 2-2, and upper rubber layer 4;

[0074] S2, the first single-side trapezoidal steel plate 2-1 and the second single-side trapezoidal steel plate 2-2 in the composite elastic sleeper pad assembly model of the ballasted track bed are 7.85×10 -9 t / mm 3 , Young's modulus is 210000MPa, yield stress is 235MPa, and Poisson's ratio is 0.3;

[0075] Table 2 Steel plate material parameters

[0076] <![CDATA[Density / (t / mm 3 )]]> Young's modulus / (MPa) Yield stress / (MPa) Poisson's ratio <![CDATA[7.85×10 -9 ]]> 210000 235 0.3

[0077] S3, the lower rubber layer 1, the middle rubber layer 3, and the upper rubber layer 4 in the composite elastic sleeper pad assembly model of the ballast track bed have a density of 0.92×10 -9 t / mm 3 , Mechanical properties constant C of rubber material 10 is 2.51133, C 01 Set it to 2.97074, select the material type of rubber as isotropic, and the constitutive model of rubber material as Mooney-Rivlin. The Mooney-Rivlin constitutive model can better describe the hyperelastic properties of rubber materials under small and medium strains;

[0078] Table 3 Rubber material parameters

[0079] <![CDATA[Density / (t / mm 3 )]]> <![CDATA[C 10 ]]> <![CDATA[C 01 ]]> <![CDATA[0.92×10 -9 ]]> 2.51133 2.97074

[0080] S4, setting a reference point RP1 at the center of the lower surface of the lower rubber layer 1, and setting a reference point RP2 at the center of the upper surface of the upper rubber layer 4;

[0081] S5. In the Create step, select the Dynamic / Explicit type, set the Time period to 7s, and in the History Output Request, select to output the mechanical parameters such as force, displacement, stress, and strain at the reference point RP2 on the upper surface of the upper rubber 4.

[0082] S6. Set the contact parameters (Interaction): Tie contact is adopted between the lower rubber layer 1 and the first single-sided trapezoidal steel plate 2-1, the first single-sided trapezoidal steel plate 2-1 and the middle rubber layer 3, the middle rubber layer 3 and the second single-sided trapezoidal steel plate 2-2, and the second single-sided trapezoidal steel plate 2-2 and the upper rubber layer 4, and the lower surface of the lower rubber layer 1 is coupled with the reference point RP1, and the upper surface of the upper rubber layer 4 is coupled with the reference point RP2;

[0083] S7. In the Load module: set the loading boundary condition: the bottom surface of the lower rubber layer 1 is fixed, that is, all 6 degrees of freedom are restricted, the upper rubber layer 4 can only move up and down, that is, 5 degrees of freedom are restricted, and a linearly increasing displacement load is applied at the reference point RP2 on the upper surface of the upper rubber layer 4;

[0084] S8. In the Mesh module, use 2 mm C3D8R mesh to mesh the lower rubber layer 1, the first single-sided trapezoidal steel plate 2-1, the middle rubber layer 3, the second single-sided trapezoidal steel plate 2-2, and the upper rubber layer 4, and submit the calculations. Analyze the mechanical properties of the elastic sleeper pad based on the calculation results.

[0085] 2. Second loading method of composite elastic sleeper pad on ballast track bed - loading concentrated force load according to actual train working conditions

[0086] The overall dimensions of the composite elastic sleeper pad are as follows: Figure 3 As shown, a = 320mm, b = 2600mm, c = 32mm. In order to improve the calculation efficiency of the composite elastic sleeper pad in the finite element software and save time cost, the composite elastic sleeper pad sample with a = 100mm, b = 100mm, c = 32mm, f = 40mm, θ = 120°, e = 4mm, d = 8mm is loaded with concentrated force loads of actual train working conditions. The modeling steps of the second loading method are as follows:

[0087] S1. Import the three-dimensional structural models of each component into the finite element software and assemble them to obtain the composite elastic sleeper pad assembly model of the ballast track bed, such as Figure 3 As shown; the specific assembly sequence is: from bottom to top, assemble in the order of lower rubber layer 1, first single-sided trapezoidal steel plate 2-1, middle rubber layer 3, second single-sided trapezoidal steel plate 2-2, and upper rubber layer 4;

[0088] S2, the first single-side trapezoidal steel plate 2-1 and the second single-side trapezoidal steel plate 2-2 in the composite elastic sleeper pad assembly model of the ballasted track bed are 7.85×10 -9 t / mm 3 , Young's modulus is 210000MPa, yield stress is 235MPa, and Poisson's ratio is 0.3;

[0089] S3, the lower rubber layer 1, the middle rubber layer 3, and the upper rubber layer 4 in the composite elastic sleeper pad assembly model of the ballast track bed have a density of 0.92×10 -9 t / mm 3 , Mechanical properties constant C of rubber material 10 is 2.51133, C 01Set it to 2.97074, select the material type of rubber as isotropic, and the constitutive model of rubber material as Mooney-Rivlin. The Mooney-Rivlin constitutive model can better describe the hyperelastic properties of rubber materials under small and medium strains;

[0090] S4, setting a reference point RP1 at the center of the lower surface of the lower rubber layer 1, and setting a reference point RP2 at the center of the upper surface of the upper rubber layer 4;

[0091] S5. In the Create step, select the Dynamic / Explicit type, set the simulation time (Time period) to 7s, and in the History OutputRequest manager (History OutputRequest), select to output the mechanical parameters such as force, displacement, stress and strain at the upper surface reference point RP2 of the upper rubber 4;

[0092] S6. Set the contact parameters (Interaction), and use the tie contact between the lower rubber layer 1 and the first single-sided trapezoidal steel plate 2-1, the first single-sided trapezoidal steel plate 2-1 and the middle rubber layer 3, the middle rubber layer 3 and the second single-sided trapezoidal steel plate 2-2, and the second single-sided trapezoidal steel plate 2-2 and the upper rubber layer 4, and couple the lower surface of the lower rubber layer 1 with the reference point RP1, and couple the upper surface of the upper rubber layer 4 with the reference point RP2;

[0093] S7. In the Load module, set the loading boundary conditions: the bottom surface of the lower rubber layer 1 is fixed, that is, all 6 degrees of freedom are restricted, the upper rubber layer 4 can only move up and down, that is, 5 degrees of freedom are restricted, and the concentrated force load of the actual train working condition is applied at the reference point RP2 on the upper surface of the upper rubber layer 4;

[0094] S8. In the Mesh module, use 2 mm C3D8R meshing for the lower rubber layer 1, the first single-sided trapezoidal steel plate 2-1, the middle rubber layer 3, the second single-sided trapezoidal steel plate 2-2, and the upper rubber layer 4, and submit the calculation. According to the calculation results, Figure 12-13 As shown. Figure 12-13 It can be seen that according to the Discrete Element-Flexible Body Coupling Analysis of Ballast-Soft Sleeper Interaction, after applying the actual load of the train to the composite elastic sleeper pad sample with a=100mm, b=100mm, c=32mm (the elastic sleeper pad is loaded with a sinusoidal wave periodic load with a peak load of 40kN, a minimum load of 3kN, and a loading frequency of only 3Hz), the displacement deformation of the composite elastic sleeper pad is small, which meets the use requirements of the sleeper pad.

[0095] The specific implementation modes of the present invention are described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above implementation modes, and various changes can be made within the knowledge scope of ordinary technicians in this field without departing from the purpose of the present invention.

Claims

1. A composite elastic sleeper pad structure for a ballasted track bed, characterized in that: include: Lower rubber layer (1); A first single-sided trapezoidal steel plate (2-1), one side of the first single-sided trapezoidal steel plate (2-1) is a plane, and the other side of the first single-sided trapezoidal steel plate (2-1) is provided with grooves arranged at intervals and the concave direction of the grooves is toward the lower rubber layer (1); one side of the plane of the first single-sided trapezoidal steel plate (2-1) is bonded to the upper surface of the lower rubber layer (1); An intermediate rubber layer (3), wherein the intermediate rubber layer (3) is provided with bosses extending from the middle to both sides, and one side of the boss of the intermediate rubber layer (3) is fixedly matched with one side of the groove of the first single-sided trapezoidal steel plate (2-1) in shape; A second single-sided trapezoidal steel plate (2-2), wherein the second single-sided trapezoidal steel plate (2-2) has the same structure as the first single-sided trapezoidal steel plate (2-1); one side of the groove of the second single-sided trapezoidal steel plate (2-2) is matched and fixed with the other side of the boss of the middle rubber layer (3); An upper rubber layer (4), the upper rubber layer (4) has the same structure as the lower rubber layer (1); the lower surface of the upper rubber layer (4) is bonded to one side of the plane of the second single-sided trapezoidal steel plate (2-2).

2. The composite elastic sleeper pad structure for ballasted track bed according to claim 1, characterized in that: The lower rubber layer (1), the first single-sided trapezoidal steel plate (2-1), the middle rubber layer (3), the second single-sided trapezoidal steel plate (2-2), and the upper rubber layer (4) form a square structure as a whole, having two first surfaces arranged opposite to each other, two second surfaces arranged opposite to each other, and two third surfaces arranged opposite to each other, wherein the first surfaces, the second surfaces, and the third surfaces are perpendicular to each other, and the lower surface of the lower rubber layer (1) and the upper surface of the upper rubber layer (4) are two first surfaces arranged opposite to each other.

3. The composite elastic sleeper pad structure for ballasted track bed according to claim 2, characterized in that: The second surface and the third surface are bonded with a protective layer of rubber (5).

4. The composite elastic sleeper pad structure for ballasted track bed according to claim 1, characterized in that: A non-woven anti-puncture layer is bonded to the lower surface of the lower rubber layer (1).

5. The composite elastic sleeper pad structure for ballasted track bed according to claim 1, characterized in that: The corners of the bosses formed by the adjacent trapezoidal grooves on one side of the grooves of the first single-sided trapezoidal steel plate (2-1) and the second single-sided trapezoidal steel plate (2-2) are rounded; the corners of the grooves formed by the adjacent bosses on both sides of the middle rubber layer (3) are rounded.

6. The composite elastic sleeper pad structure for ballasted track bed according to claim 1, characterized in that: The grooves of the first single-sided trapezoidal steel plate (2-1) and the second single-sided trapezoidal steel plate (2-2) are isosceles trapezoidal grooves, and the bosses on both sides of the middle rubber layer (3) are isosceles trapezoidal bosses.

7. A modeling method for a composite elastic sleeper pad structure of a ballasted track bed, characterized in that: The following steps are involved: Establish the three-dimensional structural model of each component of the composite elastic sleeper pad of the ballasted track bed; The three-dimensional structural models of each component are imported into the finite element software and loaded using the first / second loading method; wherein the first loading method is to load displacement loads, and the second loading method is to load concentrated force loads based on actual train operating conditions.

8. The modeling method of the composite elastic sleeper pad structure of the ballasted track bed according to claim 7 is characterized in that: The three-dimensional structural models of each component are imported into the finite element software and loaded using the first / second loading method, including: S1. Import the three-dimensional structural models of each component into the finite element software and assemble them to obtain the composite elastic sleeper pad assembly model of the ballasted track bed; S2. Setting the density, Young's modulus, yield stress and Poisson's ratio parameters of the first single-sided trapezoidal steel plate (2-1) and the second single-sided trapezoidal steel plate (2-2) in the composite elastic sleeper pad assembly model of the ballasted track bed; S3, setting the density and mechanical property parameters of the lower rubber layer (1), the middle rubber layer (3), and the upper rubber layer (4) in the composite elastic rail sleeper pad assembly model of the ballast track bed, selecting the material type of the rubber as isotropic, and the constitutive model of the rubber material as Mooney-Rivlin; S4, setting a reference point RP1 at the center of the lower surface of the lower rubber layer (1), and setting a reference point RP2 at the center of the upper surface of the upper rubber layer (4); S5, create analysis step: first select the dynamic display type; then set the simulation time; finally, in the output request manager, select to output the mechanical parameters at the upper surface reference point RP2 of the upper rubber (4); S6, setting contact parameters: adopting binding contact between the lower rubber layer (1) and the first single-sided trapezoidal steel plate (2-1), the first single-sided trapezoidal steel plate (2-1) and the middle rubber layer (3), the middle rubber layer (3) and the second single-sided trapezoidal steel plate (2-2), and the second single-sided trapezoidal steel plate (2-2) and the upper rubber layer (4); and coupling the lower surface of the lower rubber layer (1) with the reference point RP1, and coupling the upper surface of the upper rubber layer (4) with the reference point RP2; S7. In the loading module, set the loading boundary conditions: the bottom surface of the lower rubber layer (1) is fixed; S8, applying a linearly increasing displacement load or a concentrated force load according to actual train working conditions to the reference point RP2 on the upper surface of the upper rubber layer (4); S9. In the meshing module, mesh the lower rubber layer (1), the first single-sided trapezoidal steel plate (2-1), the middle rubber layer (3), the second single-sided trapezoidal steel plate (2-2), and the upper rubber layer (4), and submit the meshing for calculation. The mechanical properties of the elastic sleeper pad are analyzed based on the calculation results.

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