Rigidity homogenization method for high-speed turnout zone

Abstract

The invention relates to a rail rigidity homogenization technology, and discloses a high-speed turnout zone rigidity homogenization method which comprises the following steps: modeling a rigid vehicle and a flexible turnout rail piece, and analyzing a contact relation between the vehicle and the turnout rail piece to obtain a vehicle-turnout coupling dynamic model; the vehicle-turnout coupling dynamic model comprises a vehicle model, a turnout rail piece model and a wheel-rail contact model; simulating calculation is carried out by changing the rigidity value of the before-forking elastic base plate in the turnout rail piece model, the change of the wheel-rail dynamic effect is calculated, the influence of the before-forking rigidity change on the wheel-rail dynamic effect is obtained, the before-forking rigidity value when the wheel-rail impact effect is minimum is determined to serve as the target rigidity value, and therefore rigidity homogenization of the high-speed turnout area is completed. By simulating the actual state of each part in the turnout when the turnout is in contact with a vehicle, the risk of structural fatigue failure of a certain part in the turnout caused by the long-term train load effect is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to track stiffness homogenization technology, and in particular to a high-speed turnout area stiffness homogenization method. BACKGROUND

[0002] Turnout stiffness refers to the ability of the turnout area including straight basic rails, center rails, wing rails and other key components on the track to resist deformation when subjected to train load. It reflects the stability and durability of the turnout structure under dynamic load. When a high-speed train passes through the turnout area, the sudden change in the stiffness of the turnout area may cause wheel-rail impact and vibration to intensify, thereby affecting the running safety of the train and the comfort of passengers.

[0003] In the design of high-speed turnouts, the stiffness of the turnout area is usually greater than that of the track in the section. This sudden change in stiffness will significantly increase the wheel-rail impact force when the train passes through, thereby causing a series of problems such as fastener failure, sleeper emptying, and track bed subsidence. These problems not only reduce the service life of the turnout, but also further exacerbate the wheel-rail dynamic action, affecting the running safety and comfort of the train.

[0004] The existing track turnout area stiffness homogenization method usually homogenizes the design of turnout track stiffness by finite element method, analyzes the influence of interval iron, sliding bed, and support layer under the point / center rail plate on the stiffness of the turnout, and designs the stiffness of the turnout rail track by grading the elastic cushion layer. The overall stiffness of the turnout per sleeper is taken as the target, and the stiffness of the turnout track is homogenized by adjusting the rubber pad under the plate. However, this method only optimizes the distribution of turnout stiffness, ignoring the influence of wheel-rail dynamic load on each individual component of the turnout during actual operation, resulting in the turnout after stiffness homogenization being prone to bolt loosening and rubber pad aging under the repeated action of dynamic load. SUMMARY

[0005] The present application provides a high-speed turnout area stiffness homogenization method to solve the technical problem of the related art that the turnout after optimization of the turnout area stiffness homogenization method is prone to bolt loosening and rubber pad aging under the repeated action of dynamic load.

[0006] The present application provides a high-speed turnout area stiffness homogenization method, comprising the following steps:

[0007] Modeling a rigid vehicle and a flexible turnout rail piece and analyzing the contact relationship between the vehicle and the turnout rail piece to obtain a vehicle-turnout coupled dynamics model, the vehicle-turnout coupled dynamics model comprising a vehicle model, a turnout rail piece model, and a wheel-rail contact model;

[0008] The simulation calculation is performed by changing the stiffness value of the elastic pad plate before the turnout in the turnout rail piece model, the change of wheel-rail dynamic action is calculated, the influence of the stiffness change before the turnout on the wheel-rail dynamic action is obtained, and the stiffness value before the turnout at the minimum wheel-rail impact is determined as the target stiffness value, so as to complete the stiffness homogenization of the high-speed turnout area.

[0009] In a possible implementation, the method further includes:

[0010] The target stiffness value is used as the stiffness value of the elastic pad plate before the turnout in the turnout rail piece model, the turnout frog key section is established respectively, the mapping relationship between the stress of each component on the turnout tie and the wheel load is obtained through the turnout frog movement and stress analysis model, and the turnout tie stability is calculated.

[0011] In a possible implementation, the step of obtaining the mapping relationship between the stress of each component on the turnout tie and the wheel load through the turnout frog movement and stress analysis model includes:

[0012] The initial lateral force and vertical force are applied to the center rail or wing rail in combination with the vehicle-turnout coupled dynamics model, the stress characteristics of the turnout tie bolt structure are obtained through the finite element model, the function relationship between the wheel-rail force at the turnout frog and the stress of the turnout tie bolt is solved, and then the maximum stress position and maximum position of the turnout tie are obtained, so as to calculate the influence of the wheel-rail dynamic action on the turnout tie stability.

[0013] In a possible implementation, the step of obtaining the mapping relationship between the stress of each component on the turnout tie and the wheel load through the turnout frog movement and stress analysis model includes:

[0014] The wheel load is set as the limit value required by the specification, the stress of the turnout frog structure under the wheel-rail load is analyzed, the overall stress condition and displacement distribution of the turnout tie bolt and the turnout frog are obtained, and the influence of the wheel-rail load limit on the turnout tie stability is calculated.

[0015] In a possible implementation, the step of modeling the flexible turnout rail piece includes:

[0016] The variable cross-section profile of the turnout rail piece is generated by interpolation fitting, and the wheel-rail contact relationship between the turnout rail piece and the rigid wheel is simulated.

[0017] The finite element analysis software is used to establish the turnout rail piece beam model, the substructure analysis is performed through modal reduction, the turnout rail piece beam information file is obtained, and the turnout rail piece model is obtained, which is used to simulate the vibration deformation of the flexible turnout rail piece.

[0018] In a possible implementation, the method further comprises: splitting the profiles of the straight switch rail and the curved stock rail, and the profile of the frog rail and the wing rail in the switch rail model, and encrypting the nodes in the switch rail area and the frog rail area.

[0019] In a possible implementation, the step of modeling the rigid vehicle comprises:

[0020] Each component of the vehicle is simplified as a rigid body, a finite element model of the vehicle is established, a vehicle model is obtained, the degrees of freedom of the vehicle model are reduced, and the mass matrix, the stiffness matrix and the corresponding modal characteristics of each rail of the switch rail are solved under the premise of retaining the original properties and the calculation accuracy of the model.

[0021] In a possible implementation, the vehicle-switch coupling dynamics model further comprises:

[0022] The vehicle model and the switch rail model are connected through a wheel-rail contact model to calculate the position and area of the contact patch, the wheel-rail normal force and the wheel-rail tangential force;

[0023] The step of calculating the position and area of the contact patch comprises: determining the wheel-rail penetration in the vertical plane of the length direction of the switch rail model, and converting the actual contact area into an equivalent contact ellipse by using an equivalent elastic contact algorithm, the contact area and the wheel-rail contact force being kept unchanged in the conversion process, and the area of the contact ellipse being calculated as the contact patch area.

[0024] In a possible implementation, the step of calculating the wheel-rail normal force comprises: obtaining the wheel-rail equivalent penetration according to the semi-axle length of the contact ellipse and the wheel-rail material properties, and calculating the wheel-rail normal force

[0025] In a possible implementation, the step of calculating the wheel-rail tangential force comprises: determining the creep coefficient to obtain the relationship between the wheel-rail tangential stress and the creep rate.

[0026] The high-speed switch area stiffness homogenization method provided in the application can simulate the actual state of each component in the switch when the switch and the vehicle are in contact by establishing a joint model of the vehicle model, the switch rail model and the wheel-rail contact model, considering the actual situation of the switch in the stiffness homogenization method, and matching the stiffness of the switch area with the stiffness of the interval by optimizing the stiffness of the elastic pad, so that the state of the switch after the stiffness homogenization is closer to the actual running state of the switch, the sudden change of the lateral force and the vertical force of the train passing through the switch is reduced, the impact load between the wheel and the rail is reduced, the possibility of derailment is reduced, and the safety of train operation is improved. At the same time, the wheel-rail impact effect can be effectively reduced, the vibration of the vehicle when passing through the switch is reduced, the fatigue damage of the rail and the fastener system in the switch is reduced, and the risk of structural fatigue failure of a component in the switch caused by long-term train load is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0027] The accompanying drawings, which are incorporated herein and form a part of the specification, illustrate embodiments consistent with the present application and, together with the description, further serve to explain the principles of the application.

[0028] Figure 1 A structure diagram of a frog nose in an embodiment of the present application.

[0029] Figure 2 A finite element model diagram for analyzing the movement and stress of a frog in an embodiment of the present application.

[0030] Figure 3 A time history curve of vertical wheel-rail force when a high-speed EMU passes through a turnout in an embodiment of the present application.

[0031] Figure 4 A time history curve of lateral wheel-rail force when a high-speed EMU passes through a turnout in an embodiment of the present application.

[0032] Figure 5 A diagram of stress characteristics of a turnout sleeper bolt under dynamic wheel-rail action in an embodiment of the present application.

[0033] Figure 6 A diagram of lateral displacement distribution of a turnout sleeper bolt under dynamic wheel-rail action in an embodiment of the present application.

[0034] Figure 7 A diagram of overall lateral displacement distribution of a frog under dynamic wheel-rail action in an embodiment of the present application.

[0035] Figure 8 A diagram of stress characteristics of a turnout sleeper bolt under wheel-rail load limit in an embodiment of the present application.

[0036] Figure 9 A diagram of lateral displacement distribution of a turnout sleeper bolt under wheel-rail load limit in an embodiment of the present application.

[0037] Figure 10 A diagram of overall lateral displacement distribution of a frog under wheel-rail load limit in an embodiment of the present application.

[0038] Figure 11 A diagram of a rail torsion analysis model in an embodiment of the present application.

[0039] Figure 12 A diagram of torsional stiffness analysis of a double-layer rail under a rubber pad fastener system in an embodiment of the present application.

[0040] The specific embodiments of the application have been shown by way of example in the above figures, and will be described in more detail hereafter. These figures and this written description are not intended to limit the scope of the inventive concept in any manner, but are merely to facilitate the understanding of the inventive concept by those skilled in the art through reference to particular embodiments. DETAILED DESCRIPTION

[0041] In order to make the objects, technical solutions and advantages of the present application clearer, the technical solutions in the embodiments of the present application will be described in more detail below with reference to the drawings of the preferred embodiments of the present application. In the drawings, identical or similar reference numerals indicate identical or similar components or components having identical or similar functions throughout. The described embodiments are part of the embodiments of the present application, but not all the embodiments. The embodiments described below with reference to the drawings are exemplary and are intended to explain the present application, and cannot be understood as limiting the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application. The embodiments of the present application will be described in detail below with reference to the drawings.

[0042] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection" should be understood in a broad sense, for example, it can be fixedly connected, or indirectly connected through an intermediate medium, or the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0043] In the description of the present application, it should be understood that the terms "up", "down", "front", "back", "left", "right" and the like indicate the orientation or positional relationship shown in the drawings, and are only intended to facilitate the description of the present application and simplify the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0044] The terms "first", "second", "third", "fourth" and the like in the specification and claims of the present application and the above drawings are used to distinguish similar objects, and do not necessarily indicate a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein.

[0045] Furthermore, the terms "comprise", "comprising", "have", "having", "include", "including", "contain", "containing", "provide", "providing", "offer", "offering", "carry", "carrying", "can", "can" and any variations thereof in the description and / or the claims are intended to cover a non-exclusive inclusion, for example, a process, method, system, product or apparatus that comprises a list of steps or units can not necessarily be limited to those listed steps or units but can include other steps or units not expressly listed or inherent to such process, method, product or apparatus.

[0046] The high-speed turnout area stiffness homogenization method of the embodiments of the present application is described below in combination with the drawings.

[0047] The concrete box girder structure temperature field analysis method under fire high temperature provided by the embodiments of the present application includes the following steps:

[0048] The rigid vehicle and the flexible turnout rail piece are modeled, and the contact relationship between the vehicle and the turnout rail piece is analyzed to obtain a vehicle-turnout coupled dynamics model, wherein the vehicle-turnout coupled dynamics model includes a vehicle model, a turnout rail piece model and a wheel-rail contact model.

[0049] The stiffness value of the elastic pad plate before the turnout in the turnout rail piece model is changed to perform simulation calculation, the change of wheel-rail dynamic action is calculated, the influence of the stiffness change before the turnout on the wheel-rail dynamic action is obtained, and the stiffness value of the stiffness before the turnout at the minimum wheel-rail impact is determined as the target stiffness value to complete the high-speed turnout area stiffness homogenization.

[0050] As can be seen from the above description, the high-speed turnout area stiffness homogenization method provided by the embodiments of the present application considers the actual situation of the turnout as the turnout rail piece model in the stiffness homogenization method by establishing a joint model of the vehicle model, the turnout rail piece model and the wheel-rail contact model, which can effectively simulate the actual state of each component in the turnout when the turnout is in contact with the vehicle. In addition, by optimizing the stiffness of the elastic pad plate, the stiffness of the turnout area and the interval stiffness are matched, so that the state of the stiffness homogenization after the turnout is closer to the actual running state of the turnout, which can reduce the sudden change of lateral force and vertical force when the train passes through the turnout, reduce the impact load between the wheel and the rail, reduce the possibility of derailment, and improve the safety of train operation. At the same time, it can also effectively reduce the wheel-rail impact, reduce the vibration of the vehicle when passing through the turnout, thereby reducing the fatigue damage of the rail and the fastener system in the turnout, and reducing the risk of structural fatigue failure of a certain component in the turnout caused by long-term train load.

[0051] Here, it should be noted that in the embodiments of the present application, the vehicle model and the turnout rail piece model are respectively constructed according to the actual structure of the high-speed railway vehicle and the flexible turnout rail piece, but in order to facilitate calculation, the parameters or structures in the model can be simplified under the premise of retaining the original properties and calculation accuracy of the model. The vehicle model and the turnout rail piece model are constructed according to the actual situation, and the specific form of the vehicle model and the turnout rail piece model is not absolutely limited in the embodiments of the present application.

[0052] In some embodiments, after the step of homogenizing the stiffness of the high-speed turnout area is completed, the stability of the stiffness-homogenized turnout tie needs to be checked. The target stiffness value is used as the stiffness value of the elastic pad before the turnout in the turnout rail model, and a turnout frog movement and stress analysis model is established for each key section of the turnout frog. The mapping relationship between the stress of each component on the turnout tie and the wheel load is obtained through the turnout frog movement and stress analysis model to check the stability of the turnout tie.

[0053] The step of obtaining the mapping relationship between the stress of each component on the turnout tie and the wheel load through the turnout frog movement and stress analysis model includes:

[0054] In combination with the vehicle-turnout coupled dynamics model, an initial lateral force and a vertical force are applied to the center rail or the wing rail, and the stress characteristics of the turnout tie bolt structure are obtained through the finite element model to solve the functional relationship between the wheel rail force at the frog and the stress of the turnout tie bolt, and then the maximum stress position and the maximum position of the turnout tie are obtained to account for the influence of the wheel rail dynamic action on the stability of the turnout tie.

[0055] In addition, the wheel load is set to the limit value required by the specification, and the stress of the frog structure under the wheel rail load is analyzed to obtain the overall stress and displacement distribution of the turnout tie bolt and the frog to account for the influence of the wheel rail load limit on the stability of the turnout tie.

[0056] In some embodiments, the turnout rail model is constructed by the following method: the variable cross-section profile of the turnout rail is generated by interpolation fitting to simulate the wheel rail contact relationship formed by the turnout rail and the rigid wheel; a turnout rail beam model is established using finite element analysis software, and a substructure analysis is performed through modal reduction to obtain a turnout rail beam information file to obtain a turnout rail model, which is used to simulate the vibration deformation of the flexible turnout rail.

[0057] In the turnout rail model, the gradual change characteristics of the cross-section width and height of the turnout rail, the turnout rail, the center rail profile, and the wing rail profile need to be fully considered, and the profile of the straight rail and the curved rail, the center rail and the wing rail needs to be split and not considered as a unified whole. In the modeling process of the turnout rail beam, special attention should be paid to node encryption in the sharp rail area and the center rail area where the shape changes sharply to better simulate the shape of the turnout rail beam and ensure the calculation accuracy.

[0058] In some embodiments, the vehicle model is constructed by the following method: each component of the vehicle is simplified as a rigid body, a finite element model of the vehicle is established to obtain the vehicle model, and the degrees of freedom of the vehicle model are reduced. The mass matrix, stiffness matrix, and corresponding modal characteristics of each rail of the turnout rail are solved under the premise of preserving the original properties and calculation accuracy of the model.

[0059] Specifically, the high-speed railway vehicle is a multi-body system composed of a car body, a bogie, a wheelset and other components. The interaction between adjacent components has nonlinear characteristics, and the wheel-rail contact relationship is relatively complex. In the present embodiment, in order to balance the model accuracy and the calculation efficiency, each component of the vehicle model is simplified as a rigid body in the modeling process, including 1 car body, 2 bogies, 4 wheelsets and 8 axle boxes. After the finite element model of the rigid vehicle is established, the Craig-Bampton substructure analysis method is used to reduce the degrees of freedom of the finite element model, and the mass matrix, the stiffness matrix and the corresponding modal characteristics of each rail piece of the turnout rail piece are solved under the premise of preserving the original properties and the calculation accuracy of the model.

[0060] In some embodiments, in the vehicle-turnout coupled dynamics model, the mutual coupling of the vehicle model and the turnout rail piece model is realized through a wheel-rail contact model in series, which is used to solve the contact spot position and area, the wheel-rail normal force and the wheel-rail tangential force. In order to calculate the position and number of the contact spots, the wheel-rail penetration amount is determined in the vertical plane of the length direction of the turnout rail piece model, and an equivalent elastic contact algorithm is used to convert the actual contact area into an equivalent contact ellipse, and the contact area and the wheel-rail contact force remain unchanged in the conversion process. Based on the Hertz nonlinear elastic contact theory, the wheel-rail equivalent penetration amount is obtained according to the semi-axle length of the contact ellipse and the wheel-rail material properties, and the wheel-rail normal force is calculated; the wheel-rail tangential force is calculated by using the FASTSIM algorithm, the creep coefficient is determined, and the relationship between the wheel-rail tangential stress and the creep rate is obtained. Due to the inherent irregularities in the turnout rail piece area, multiple-point contact often occurs, and the size of the contact position and the contact angle will further affect the wheel-rail dynamic response. According to the above rigid car body model, the flexible turnout rail piece model and the wheel-rail contact model, the establishment of the rigid-flexible coupled dynamics model of the vehicle-turnout rail piece is finally realized.

[0061] When the turnout replaces a new elastic pad stiffness, the stiffness of the turnout area will change. The present embodiment mainly considers the influence of the sudden change of the elastic pad stiffness before the turnout on the dynamic performance of the turnout area, and reveals the influence of the change of the overall stiffness under the rail. The calculation condition parameters are shown in Table 1, wherein the stiffness of the straight basic rail before the turnout, in the turnout area and after the turnout in the original scheme is 23 kN / mm, 25 kN / mm and 23 kN / mm respectively, and the working conditions 1 to 6 are the optimized scheme.

[0062] Table 1 Calculation condition parameters

[0063]

[0064] The calculation results of the influence of the change of the stiffness before the turnout on the wheel-rail dynamic action are shown in Table 2.

[0065] Table 2 Influence of the change of the stiffness before the turnout on the wheel-rail dynamic action

[0066]

[0067] From the above calculation results, it can be seen that the stiffness of the existing passenger special line turnout area is greater than that of the section, and the sudden change of stiffness leads to wheel-rail dynamic impact and excitation of vehicle vibration. At the two kinds of track connections, the sleeper pressure changes very sharply, and under the action of long-term train load, it is easy to cause fastener failure, sleeper empty suspension or damage, track bed subsidence and other line diseases. Once the line appears diseases, the wheel-rail dynamic action will be worsened, which seriously affects the safety and comfort of train operation. Therefore, based on the simulation results of the influence of different turnout area stiffness, when the target stiffness is set to about 22kN / mm, the wheel-rail impact action is relatively the smallest, and it is the most reasonable to match the section.

[0068] Next, according to the above turnout stiffness homogenization results, the turnout stability is calculated. In this embodiment, the minimum rubber pad stiffness of the turnout laid on the line is set to 16kN / mm, which is laid near the frog point of the switch rail. The decrease of rubber pad stiffness will lead to the decrease of fastener torsional stiffness, and then cause the dynamic gauge expansion under the action of lateral force. On the other hand, with the same rubber pad stiffness under the plate, the fastener torsional stiffness can be increased if the length of the rubber pad increases. At the frog point of the switch rail, although the stiffness of the rubber pad under the plate is the smallest, and the length of the rubber pad is also smaller, but here the iron pad plate is shared by two wing rails, and the wheel lateral force is borne by the frame structure composed of two wing rails and fastener system. As shown in Figure 1 , when the wheel lateral force acts on one wing rail, the rubber pad under the rail and the iron pad plate will tilt, and due to the tilt of the iron pad plate being limited by the other wing rail, the torsional stiffness of the fastener will be greatly increased. In addition, the stiffness of the rubber pad under the rail is very large, so even if the stiffness of the rubber pad under the plate decreases, it will not reduce the torsional stiffness of the entire fastener system. Therefore, although the stiffness of the rubber pad under the plate is the smallest at the switch rail tip, the torsional stiffness of the fastener system here is not the smallest.

[0069] In addition, after the stiffness homogenization of the high-speed ballastless track turnout, the stiffness of the rubber pad under the plate changes from 25kN / mm to 22kN / mm, which is reduced to a certain extent, which may affect the stress characteristics of the entire turnout structure, cause damage to the turnout rail turnout sleeper bolt structure under the action of repeated train load, and then affect the service performance of the entire turnout, so it is necessary to analyze the movement and stress of the complex structure of high-speed turnout. In this embodiment, taking the design value of the rubber pad stiffness under the plate as 16kN / mm as an example, the movement and stress analysis model of the turnout frog is modeled, considering the linear and nonlinear factors under the action of train load, and the mapping relationship between the stress of turnout sleeper bolt and wheel load is explored through the movement and stress analysis model of the turnout frog.

[0070] To explore the force interaction between the structure of frog tie bolt and wheel load, the force transmission relationship from rail head to frog tie bolt needs to be clarified, and the movement and stress principle of frog need to be explored. The frog is mainly composed of wing rail, center rail, sliding bed, iron pad, frog tie bolt, bolt and other structures. The force calculated by the vehicle-turnout coupling dynamics is applied to the turnout rail as the initial condition. The wheel load borne by the center rail and wing rail is first transmitted to the rail brace and iron pad through the lateral bolt and rail pad, and then the load of the rail brace and rail pad is transmitted to the frog tie bolt through the vulcanized pad under the action of the vertical bolt.

[0071] Under the condition of ensuring the contact points and contact area of each component of the frog unchanged, the structure outside the contact area of the frog is simplified, and the finite element method is used to establish the movement and stress analysis model of the frog. In order to more truly simulate the stress environment of the transition structure under actual conditions, the constraint conditions of this calculation model are as follows: first, the rail pad, the pad pad and the vulcanized pad are simulated by springs, and the stiffness is equivalent to the actual stiffness of the pad; A certain degree of pre-warning force is applied to the lateral bolt, vertical bolt and frog tie bolt, and the interaction between the bolt and the rest of the components is simulated by contact; the interaction between the center rail / wing rail and the center rail and the rail brace, sliding bed plate, etc. is simulated by contact; for the welded parts, the binding constraint simulation is adopted.

[0072] The final movement and stress analysis model of the frog is shown in Figure 2 The material parameters of the center rail, wing rail, rail brace, iron pad, etc. are referred to the material parameters of steel, see Table 3.

[0073] Table 3 Material parameters

[0074] Material Elastic modulus / MPa Friction coefficient Density / kg / m3 Poisson's ratio Steel 2.059e5 0.3 7790 0.3

[0075] The frog movement and stress analysis model is established for each key section of the turnout frog. Combined with the vehicle-turnout coupling dynamics model, a certain initial lateral force and vertical force are applied to the center rail or wing rail, and the stress characteristics of the frog tie bolt and other structures are obtained by the finite element model, so as to solve the function relationship between the wheel rail force and the stress of the frog tie bolt, and reveal the influence law of the wheel rail dynamic force on the stress characteristics of the frog tie bolt when the stiffness of the pad pad decreases.

[0076] 1) Wheel rail dynamic action

[0077] As Figure 3 and Figure 4The time history curves of wheel-rail lateral force and wheel-rail vertical force when the high-speed train passes through the turnout in the embodiment are shown. According to the calculation results of vehicle-turnout coupling dynamics, when the wheel load is transferred between the wing rail and the center rail, wheel-rail impact load is formed, and the lateral component of the wheel-rail impact load again causes the amplitude of the wheel-rail lateral force to reach 17.6 kN. When the wheel load is transferred between the wing rail and the center rail, wheel-rail impact load is formed, and the amplitude of the wheel-rail impact load is 119.7 kN, which is 2.1 times the static wheel load.

[0078] The wheel-rail vertical force 119.7 kN and the wheel-rail lateral force load 17.6 kN calculated above are applied to the wing rail and the center rail as wheel loads, and the stress of the frog structure under the wheel load is analyzed. The overall stress and displacement distribution of the frog bolt and the frog are as shown in Figures 5 to 7 It can be seen from the figure that under the action of the wheel load, the maximum stress of the frog bolt is located at the bolt rod, and the maximum value is 38.6 MPa, which is less than the yield strength and shear strength of the bolt. Therefore, when the under-plate rubber pad is reduced to 16 kN / mm, the wheel load will not cause the existing frog bolt to break. The corresponding maximum lateral displacement is located at the top of the bolt, and the maximum displacement is 0.52 mm. The maximum lateral displacement occurring at the rail head of the wing rail is 1.58 mm, which is less than the requirement of the specification.

[0079] 2) Wheel-rail load limit

[0080] When the wheel load reaches the limit required by the specification, that is, the wheel vertical load is 170 kN, and the wheel-rail lateral load is about 30 kN, the stress of the frog structure under the wheel load is analyzed. The overall stress and displacement distribution of the frog bolt and the frog are as shown in Figures 8 to 10 It can be seen from the figure that under the action of the wheel load, the stress and displacement distribution of the frog and the frog bolt are similar. Among them, the maximum stress of the frog bolt is located at the bolt rod, and the maximum value is 55.3 MPa, which is less than the yield strength and shear strength of the bolt. Therefore, when the under-plate rubber pad is reduced to 16 kN / mm, the wheel load will not cause the existing frog bolt to break. The corresponding maximum lateral displacement is located at the top of the bolt, and the maximum displacement is 0.943 mm. The maximum lateral displacement occurring at the rail head of the wing rail is 1.796 mm, which is less than the requirement of the specification.

[0081] For a single-layer rail under-pad fastener system, if the rail is twisted, the elasticity of the rail pad and the fastener will generate a resisting moment. Assuming that the size of the resisting moment is proportional to the twist angle of the rail. Then the part of the resisting moment generated by the elasticity of the rail pad and the fastener can be calculated by the following formula:

[0082]

[0083] In the formula, k w is the torsional stiffness of the rail under-pad and the fastener.

[0084] The resistance moment per unit length generated by the rail pad and fastener is:

[0085]

[0086] In the above formula, a s is the rail bottom width; k c , k p is the vertical spring stiffness of the set of fasteners and rail pad; a f is the distance between the two fastener pressing points of a rail; a f = a s -0.02 (m); Φ is the torsion angle of the rail; a is the sleeper spacing.

[0087] The calculation formula of the distributed torsional stiffness generated by the rail pad and fastener can be obtained as:

[0088]

[0089] As Figure 11 shown in the double-layer rail pad fastener system, when the rail is twisted, the fastener and the rail pad will generate a resistance moment. Let the absolute torsion angle of the rail be Φ, the torsion angle of the rail relative to the rail pad be Φ1, and the torsion angle of the rail pad relative to the sleeper be Φ2, then the absolute torsion angle of the rail is:

[0090] Φ = Φ1 + Φ2

[0091] This shows that: if the torsional stiffness of the pressing piece and the upper pad is equivalent to the torsional spring k w1 , and the torsional stiffness of the anchor bolt and the lower pad is equivalent to the torsional spring k w2 , then the two torsional springs are in series, and the torsional stiffness k w of the entire fastener system is:

[0092]

[0093] The resistance moment generated by the pressing piece and the upper pad is

[0094]

[0095] In the above formula: k aps , k ac is the vertical stiffness of the upper pad and the fastener per unit length; Φ1 is the torsion angle of the rail; a s is the rail bottom width; a fs is the distance between the two pressing points.

[0096] Let Φ1 be 1, then M k1This equals the torsional stiffness of the clamping component and the upper rubber pad. Therefore, the torsional stiffness of the clamping component and the upper rubber pad is:

[0097]

[0098] The lower rubber pad and anchor bolts will work together to resist the tilting of the iron pad, such as Figure 12 As shown. The iron pad is tilted, with the top surface of one end of the pad away from the anchor nut, and the top surface of the other end pressing against the anchor nut. Therefore, only one bolt is resisting the tilting of the iron pad. The torque of the anchor bolt and the lower rubber pad resisting the tilting of the pad is:

[0099]

[0100] In the formula: k apx k is the vertical stiffness of the lower rubber pad per unit length. L Φ2 is the linear stiffness of an anchor bolt; Φ2 is the rail torsion angle; a x The length of the iron pad along the longitudinal direction of the sleeper; a fx The distance between the two anchor bolts.

[0101] Let Φ2 be 1, then M k2 This equals the torsional stiffness of the anchor bolt and the lower rubber pad. Therefore, the torsional stiffness of the anchor bolt and the lower rubber pad is:

[0102]

[0103] The overall torsional stiffness of the double-layer rail under-rail rubber pad fastener system can be obtained as follows:

[0104]

[0105] The overall torsional resistance calculation parameters are shown in Table 4, and the calculation results are shown in Table 5. In the table, "general track" refers to tracks using concrete sleepers, Type II elastic rail fasteners, and 60-10-15 rail pads. The results show that, after implementing uniform measures, the minimum torsional stiffness of the fasteners at straight-through turnouts is greater than that of general tracks.

[0106] Table 4 Torsional Calculation Parameters

[0107]

[0108] Table 5 Comparison of torsional stiffness calculation results

[0109] Line conditions 400 km / h Generally Torsional stiffness (N.m) / m / rad 632460 227200

[0110] Other embodiments of the application will be apparent to those skilled in the art from consideration of the specification and practice of the application disclosed herein. It is intended that the specification and examples be considered as exemplary only, with the true scope and spirit of the application being indicated by the following claims.

[0111] It is to be understood that the application is not limited to the precise construction herein disclosed and shown in the drawings, and that various changes in shape, size and arrangements of parts can be made without departing from the scope of the application. The scope of the application is limited only by the claims that follow.

Claims

1. A method of homogenizing stiffness in a high-speed switch area, characterized by, The method comprises the following steps: Modeling the rigid vehicle and the flexible turnout rail piece and analyzing the contact relationship between the vehicle and the turnout rail piece to obtain a vehicle-turnout coupled dynamic model, wherein the vehicle-turnout coupled dynamic model comprises a vehicle model, a turnout rail piece model and a wheel-rail contact model; The influence of the change of the stiffness of the turnout rail piece model on the wheel-rail dynamic action is obtained by changing the stiffness value of the elastic pad before the turnout in the turnout rail piece model to simulate and calculate the change of the wheel-rail dynamic action, and the stiffness value of the turnout before the turnout at which the wheel-rail impact action is the smallest is determined as a target stiffness value to complete the stiffness homogenization of the high-speed turnout area.

2. The method of high speed switch area stiffness equalization of claim 1, wherein, Further comprising: The target stiffness value is used as the stiffness value of the elastic pad before the turnout in the turnout rail piece model, a frog movement and stress analysis model is established for each key section of the frog, and the mapping relationship between the stress of each component on the turnout tie and the wheel load action is obtained through the frog movement and stress analysis model to check the stability of the turnout tie.

3. The method of high speed switch area stiffness equalization of claim 2, wherein, The step of obtaining the mapping relationship between the stress of each component on the turnout tie and the wheel load action through the frog movement and stress analysis model comprises: In combination with the vehicle-turnout coupled dynamic model, an initial lateral force and a vertical force are applied to the center rail or the wing rail, the stress characteristics of the turnout tie bolt structure are obtained through the finite element model, the functional relationship between the wheel-rail force at the frog and the stress of the turnout tie bolt is solved, and then the maximum stress position and the maximum position of the turnout tie are obtained to check the influence of the wheel-rail dynamic action on the stability of the turnout tie.

4. The method of claim 2, wherein, The step of obtaining the mapping relationship between the stress of each component on the turnout tie and the wheel load action through the frog movement and stress analysis model comprises: The wheel load is set as the limit value required by the specification, the stress of the frog structure under the wheel-rail load action is analyzed, the overall stress condition and displacement distribution of the turnout tie bolt and the frog are obtained, and the influence of the wheel-rail load limit on the stability of the turnout tie is checked.

5. The method of high-speed switch area stiffness equalization according to any one of claims 1 to 4, characterized in that, The step of modeling the flexible turnout rail piece comprises: A turnout rail piece variable cross-section profile is generated through interpolation fitting to simulate the wheel-rail contact relationship formed by the turnout rail piece and the rigid wheel; A turnout rail piece beam model is established by using a finite element analysis software, a substructure analysis is performed through modal reduction, a turnout rail piece beam information file is obtained, and a turnout rail piece model is obtained, wherein the turnout rail piece model is used to simulate the vibration deformation of the flexible turnout rail piece.

6. The method of high speed switch area stiffness homogenization of claim 5, wherein, Further comprising: In the turnout rail piece model, the profiles of the straight switch rail and the curved basic rail, the center rail and the wing rail are split and processed, and the node encryption processing is performed on the switch rail area and the center rail area.

7. The method of high speed turnout area stiffness homogenization according to any one of claims 1 to 4, characterized in that, The step of modeling the rigid vehicle comprises: Each component of the vehicle is simplified as a rigid body, a finite element model of the vehicle is established, a vehicle model is obtained, the degrees of freedom of the vehicle model are reduced, and the mass matrix, the stiffness matrix and the corresponding modal characteristics of each rail piece of the turnout rail piece are solved under the premise of preserving the original properties and the calculation accuracy of the model.

8. The method of high speed turnout area stiffness homogenization according to any one of claims 1 to 4, characterized in that, The vehicle-turnout coupled dynamic model further comprises: The vehicle model and the turnout rail piece model are connected in series through the wheel-rail contact model to calculate the contact spot position and area, the wheel-rail normal force and the wheel-rail tangential force; The step of calculating the position and area of the contact patch comprises: determining the wheel-rail penetration in the vertical plane along the length direction of the turnout rail piece model, and converting the actual contact area into an equivalent contact ellipse by using an equivalent elastic contact algorithm, the contact area and the wheel-rail contact force being kept unchanged during the conversion, and the area of the contact ellipse being calculated as the contact patch area.

9. The method of high speed switch area stiffness equalization of claim 8, wherein, The step of calculating the wheel-rail normal force comprises: obtaining the wheel-rail equivalent penetration according to the semi-axes of the contact ellipse and the wheel-rail material properties, and calculating the wheel-rail normal force.

10. The method of high speed switch area stiffness equalization of claim 8, wherein, The step of calculating the wheel-rail tangential force comprises: determining the creep coefficient, and obtaining the relationship between the wheel-rail tangential stress and the creep rate.

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