Simulation Method and System for Three-Dimensional Wheel-Rail Contact Model in Switch Area

Abstract

This invention provides a simulation method and system for a three-dimensional wheel-rail contact model in a switch area, belonging to the field of railway engineering technology. The method includes: applying a gravity load to the wheel-rail finite element model of the switch area based on its structural contact characteristics to generate an initial static displacement field; applying an initial angular velocity to the wheelset based on the initial static displacement field; determining an asymmetric quasi-steady-state solution under the wheel-rail structural contact characteristics of the switch area based on the initial angular velocity application result; generating a dynamic relaxation file based on the asymmetric quasi-steady-state solution to record the steady-state displacement and stress state of each node in the switch area; loading the dynamic relaxation file as the initial state; simulating the process of the wheelset passing through the switch area; and outputting real-time dynamic response results. This invention effectively improves the numerical stability and physical consistency of the wheel-rail dynamic response in the switch area, providing a reliable foundation for accurately analyzing wheel-rail interaction and the safety performance of the switch area.

Description

Technical Field

[0001] This invention relates to the field of railway engineering technology, specifically to a simulation method and system for a three-dimensional wheel-rail contact model in a switch area. Background Technology

[0002] With the increasing speed of railway transportation and the large-scale application of complex track structures, switch areas, as critical components of railway lines, exhibit complex structures, variable stress conditions, and wheel-rail contact states significantly different from ordinary straight track sections. Therefore, they have received considerable attention in wheel-rail dynamics simulation and safety assessment. Currently, the three-dimensional modeling and dynamic simulation of wheel-rail contact characteristics in switch areas mainly rely on numerical simulation methods such as finite element analysis. By establishing finite element models of the track and wheel assembly in the switch area, parameters such as wheel-rail contact force and track structure stress response are calculated to guide engineering design and safety assessment. However, existing related schemes still have certain limitations in the initial loading and contact characteristic representation, affecting simulation accuracy and numerical stability.

[0003] In existing technologies for wheel-rail contact modeling in switch areas, simplified loading methods are often used to directly apply initial angular velocities or assign target velocities to the wheelsets to quickly establish initial dynamic conditions. However, this loading method, lacking a complete static contact equilibrium and the natural evolution process of multi-point contact states, easily introduces numerical perturbations, leading to problems such as abrupt changes in contact forces, abnormal nodal stresses, or energy non-conservation during simulation. This is particularly evident in complex structures like switch areas with multi-point contact and significant gauge variations, affecting the physical consistency and numerical convergence of subsequent transient dynamic solutions.

[0004] Existing schemes generally fail to fully consider the spatial asymmetry and multi-point contact distribution characteristics of wheel-rail contact in the switch area during initial state modeling. They often express the wheel-rail contact state using idealized, symmetrical, or locally simplified methods, making it difficult to accurately reflect the comprehensive influence of different track components (such as switch rails, frogs, guard rails, etc.) on wheel-rail interaction in the switch area. This leads to certain deviations in simulation results regarding contact force distribution, track component stress, and wheel-rail dynamic response, limiting their applicability in engineering applications such as switch area safety analysis and structural fatigue assessment.

[0005] Therefore, how to achieve physical equilibrium consistency of initial state loading in wheel-rail contact simulation in the switch area, accurately express multi-point contact state and spatial asymmetric contact characteristics, and improve simulation accuracy and convergence stability are important problems that need to be solved by existing technologies. Summary of the Invention

[0006] The purpose of this invention is to provide a simulation method and system for a three-dimensional wheel-rail contact model in the switch area, so as to at least solve the problems in the prior art where the initial state loading of the wheel-rail contact simulation in the switch area is prone to disturbance, and the contact state is difficult to accurately express spatial asymmetry and multi-point contact characteristics.

[0007] To achieve the above objectives, the first aspect of the present invention provides a simulation method for a three-dimensional wheel-rail contact model of a switch zone. The method includes: applying a gravity load to a wheel-rail finite element model of the switch zone based on the structural contact characteristics of the switch zone to generate an initial static displacement field; applying an initial angular velocity to the wheelset based on the initial static displacement field; determining an asymmetric quasi-steady-state solution under the wheel-rail structural contact characteristics of the switch zone based on the initial angular velocity application result; generating a dynamic relaxation file based on the asymmetric quasi-steady-state solution to record the steady-state displacement and stress state of each node in the switch zone; loading the dynamic relaxation file as the initial state; performing a simulation of the wheelset passing through the switch zone; and outputting real-time dynamic response results.

[0008] Optionally, the wheel-rail finite element model of the switch area includes: a switch area rail finite element sub-model, a wheelset finite element sub-model, a wheel-rail contact element sub-model, and a support constraint and boundary condition sub-model; the switch area rail finite element sub-model is used to describe the switch structure and the turnout connection section structure; the wheelset finite element sub-model is used to describe the static mechanical characteristics of the wheelset; the wheel-rail contact element sub-model is used to describe the contact mechanical characteristics of the wheelset tread and the contact surface between the rail and the switch area; the support constraint and boundary condition sub-model is used to apply support boundary conditions to the switch area rail finite element sub-model and to apply degree-of-freedom constraint conditions to the wheelset finite element sub-model.

[0009] Optionally, the rule for applying gravity load to the wheel-rail finite element model in the switch area is as follows: A static vertical gravity load corresponding to the wheelset and sprung mass is applied to the wheel nodes of the wheelset finite element sub-model according to preset working parameters to form the initial static load of the wheelset acting on the rail surface in the switch area; after the initial static load of the wheelset acting on the rail surface in the switch area is applied, support boundary constraints are applied to the rail finite element sub-model in the switch area to fix the positions of the rail ends and intermediate support points; after the rail boundary constraints are applied, the wheel-rail contact element sub-model is activated to transfer the load of the nodes to the rail surface through the wheel-rail contact element sub-model, thus obtaining the wheel-rail finite element model in the switch area with applied gravity load.

[0010] Optionally, the rule for generating the initial static displacement field is as follows: Static equilibrium calculations are performed on the wheel-rail finite element model of the switch area under applied gravity load to obtain the initial equilibrium displacements of the wheelset nodes and rail nodes under the combined action of gravity load and support constraints; during the static equilibrium calculation, the normal force, tangential force, and contact stiffness of each contact point of the wheel-rail contact unit are monitored in real time until the static equilibrium state converges, obtaining the node displacement vectors, node stress tensors, and wheel-rail contact force states under convergence conditions; the obtained node displacement vectors, node stress tensors, and wheel-rail contact force states are used as the initial static displacement field.

[0011] Optionally, an initial angular velocity is applied to the wheelset based on the initial static displacement field, and the asymmetric quasi-steady-state solution under the wheel-rail structure contact characteristics in the switch area is determined based on the initial angular velocity application result. This includes: applying the target initial angular velocity to the axle rotational degrees of freedom of the wheelset finite element sub-model based on the initial static displacement field, and synchronously applying the target initial angular velocity to the rotational degrees of freedom of each wheel in the wheelset; during the initial angular velocity application process, based on the wheel-rail structure contact characteristics in the switch area, solving the centrifugal force field under the action of the wheelset rotational inertia in real time, and determining the wheel-rail contact parameters of each contact point of the wheel-rail contact unit to obtain the asymmetric quasi-steady-state contact state; based on the asymmetric quasi-steady-state contact state, continuously monitoring the physical field parameters of the asymmetric quasi-steady-state contact state until the contact stress state converges, and taking the physical field parameters of the asymmetric quasi-steady-state contact state in the converged state as the asymmetric quasi-steady-state solution.

[0012] Optionally, the wheel-rail contact parameters of each contact point of the wheel-rail contact unit include any one or more of the following: normal force, tangential force, contact stiffness, and contact area distribution of each contact point; the physical field parameters of the asymmetric quasi-steady-state contact state include any one or more of the following: wheel-rail contact point stress, nodal stress tensor, nodal displacement vector, and wheel-rail contact force state.

[0013] Optionally, generating a dynamic relaxation file based on the asymmetric quasi-steady-state solution to record the steady-state displacement and stress state of each node in the switch region includes: classifying the physical field parameters of each node in the asymmetric quasi-steady-state solution according to the node number to obtain multiple datasets, and forming a quasi-steady-state data structure containing complete physical field states based on each dataset; recording the quasi-steady-state data structure in a dynamic relaxation file format to obtain an initial dynamic relaxation file; wherein, each data entry in the dynamic relaxation file format includes the spatial position, steady-state displacement, steady-state stress, steady-state strain of the corresponding node and the wheel-rail contact parameters of the corresponding contact point; performing a consistency check on the generated initial dynamic relaxation file, and outputting a dynamic relaxation file that passes the consistency check.

[0014] Optionally, the dynamic relaxation file is loaded as the initial state, and the process of the wheelset passing through the switch area is simulated, and the real-time dynamic response results are output. This includes: loading the physical field parameters recorded in the dynamic relaxation file into the wheel-rail finite element model of the switch area after the gravity load is applied, as the initial conditions for simulation to simulate the process of the wheelset passing through the switch area; during the simulation, the dynamic response of the wheel-rail finite element model of the switch area under centrifugal force, wheel-rail contact force and support constraint is solved in real time, and the dynamic response parameters of each wheel and rail are output in real time as the real-time dynamic response results.

[0015] Optionally, the wheel-rail dynamic response parameters include any one or more of the following: wheelset displacement time history, wheel-rail contact force time history, nodal stress variation, hourglass energy variation, and internal energy variation.

[0016] A second aspect of the present invention provides a simulation system for a three-dimensional wheel-rail contact model of a switch zone. The system includes: an initialization unit, used to apply a gravity load to the wheel-rail finite element model of the switch zone based on the structural contact characteristics of the switch zone, generating an initial static displacement field; a processing unit, used to apply an initial angular velocity to the wheelset based on the initial static displacement field, and determine an asymmetric quasi-steady-state solution under the wheel-rail structural contact characteristics of the switch zone based on the initial angular velocity application result; a fitting unit, used to generate a dynamic relaxation file for recording the steady-state displacement and stress state of each node in the switch zone based on the asymmetric quasi-steady-state solution; and a simulation unit, used to load the dynamic relaxation file as the initial state, perform a simulation of the wheelset passing through the switch zone, and output real-time dynamic response results.

[0017] Through the above technical solution, this invention achieves physical equilibrium initialization of the wheel-rail contact state by applying gravity loads and generating an initial static displacement field based on the structural contact characteristics of the switch area, effectively avoiding the initial disturbances easily introduced when directly applying wheelset speed. By applying an initial angular velocity on the basis of the static displacement field, a quasi-steady-state solution conforming to the multi-point contact and spatial asymmetry characteristics of the switch area is further determined, enabling the initial state to truly reflect the actual working conditions of wheel-rail contact in the switch area. A dynamic relaxation file is generated based on this quasi-steady-state solution, allowing the displacement, stress, and contact state of the initial conditions to be fully loaded into subsequent process simulations. Finally, transient dynamic simulations are conducted based on the loaded dynamic relaxation file, effectively improving the numerical stability and physical consistency of the wheel-rail dynamic response in the switch area, providing a reliable foundation for accurately analyzing wheel-rail interaction and the safety performance of the switch area.

[0018] Other features and advantages of the embodiments of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0019] The accompanying drawings are provided to further illustrate embodiments of the present invention and form part of the specification. They are used together with the following detailed description to explain the embodiments of the present invention, but do not constitute a limitation thereof. In the drawings:

[0020] Figure 1 This is a flowchart of the steps of a three-dimensional wheel-rail contact model simulation method for a switch area provided by one embodiment of the present invention;

[0021] Figure 2 This is a comparison diagram of the time history of vertical wheel-rail force on a straight main rail, provided by one embodiment of the present invention and a conventional solution.

[0022] Figure 3 This is a comparison diagram of the vertical wheel-rail force time history of the present invention and the traditional solution provided by one embodiment of the present invention in the case of curved track.

[0023] Figure 4 This is a comparison diagram of the time history of vertical wheel-rail force on a straight tip rail, provided by one embodiment of the present invention, and a conventional solution.

[0024] Figure 5 This is a comparison diagram of the time history of lateral wheel-rail force on a straight main rail, provided by one embodiment of the present invention and a conventional solution.

[0025] Figure 6 This is a comparison diagram of the time history of the lateral wheel-rail force on the curved track, provided by one embodiment of the present invention and a traditional solution.

[0026] Figure 7 This is a comparison diagram of the time history of lateral displacement of wheelset provided by one embodiment of the present invention and a conventional solution;

[0027] Figure 8 This is a comparison diagram of the time history of the hourglass energy and internal energy changes of the rails of the switch, provided by one embodiment of the present invention and the conventional solution.

[0028] Figure 9 This is a comparison diagram of the time history of the hourglass energy and internal energy changes of wheelsets in one embodiment of the present invention and a traditional solution.

[0029] Figure 10 This is a comparison diagram of the vertical wheel-rail force spectrum of a straight main rail, provided by one embodiment of the present invention, and a conventional solution.

[0030] Figure 11 This is a comparison diagram of the vertical wheel-rail force spectrum of the curved base rail provided by one embodiment of the present invention and the traditional solution.

[0031] Figure 12This is a system structure diagram of a three-dimensional wheel-rail contact model simulation system for the switch area provided in one embodiment of the present invention. Detailed Implementation

[0032] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0033] Figure 1 This is a flowchart illustrating the steps of a three-dimensional wheel-rail contact model simulation method for a switch area provided by one embodiment of the present invention. Figure 1 As shown, this invention provides a simulation method for a three-dimensional wheel-rail contact model in a switch area, the method comprising:

[0034] Step S10: Based on the structural contact characteristics of the switch area, apply gravity load to the wheel-rail finite element model of the switch area to generate the initial static displacement field.

[0035] Specifically, the wheel-rail finite element model of the switch area includes: a switch area rail finite element sub-model, a wheelset finite element sub-model, a wheel-rail contact element sub-model, and a support constraint and boundary condition sub-model; the switch area rail finite element sub-model is used to describe the switch structure and the turnout connection section structure; the wheelset finite element sub-model is used to describe the static mechanical characteristics of the wheelset; the wheel-rail contact element sub-model is used to describe the contact mechanical characteristics of the wheelset tread and the contact surface between the rail and the switch area; the support constraint and boundary condition sub-model is used to apply support boundary conditions to the switch area rail finite element sub-model and to apply degree-of-freedom constraint conditions to the wheelset finite element sub-model.

[0036] Furthermore, the rules for applying gravity loads to the wheel-rail finite element model in the switch area are as follows: Static vertical gravity loads corresponding to the wheelset and sprung mass are applied to the wheel nodes of the wheelset finite element sub-model according to preset working parameters to form the initial static load of the wheelset acting on the rail surface in the switch area; after the initial static load of the wheelset acting on the rail surface in the switch area is applied, support boundary constraints are applied to the rail finite element sub-model in the switch area to fix the positions of the rail ends and intermediate support points; after the rail boundary constraints are applied, the wheel-rail contact element sub-model is activated to transfer the load of the nodes to the rail surface through the wheel-rail contact element sub-model, thus obtaining the wheel-rail finite element model in the switch area with applied gravity loads.

[0037] Furthermore, the rules for generating the initial static displacement field are as follows: Static equilibrium calculations are performed on the wheel-rail finite element model of the switch area under applied gravity load to obtain the initial equilibrium displacements of the wheelset nodes and rail nodes under the combined action of gravity load and support constraints; during the static equilibrium calculation process, the normal force, tangential force, and contact stiffness of each contact point of the wheel-rail contact unit are monitored in real time until the static equilibrium state converges, obtaining the node displacement vectors, node stress tensors, and wheel-rail contact force states under convergence conditions; the obtained node displacement vectors, node stress tensors, and wheel-rail contact force states are used as the initial static displacement field.

[0038] In this embodiment of the invention, based on the structural contact characteristics of the switch area, a gravity load is applied to the wheel-rail finite element model of the switch area to generate an initial static displacement field. This is a fundamental step in achieving physical consistency and numerical convergence in the wheel-rail simulation of the switch area. This process requires combining the actual structural characteristics of the switch area, wheel-rail contact conditions, and static boundary conditions, and through step-by-step loading and solving, to achieve a complete physical equilibrium state of the wheel-rail system under static conditions. To ensure simulation accuracy and engineering usability, the applied loads and solution steps must be strictly set according to the actual physical conditions, and the changes in key physical parameters must be monitored in real time during the solution process to ensure the validity and convergence of the data.

[0039] A complete wheel-rail finite element model of the switch area should be constructed as the physical basis for the entire simulation loading and solution. The wheel-rail finite element model of the switch area includes a switch area rail finite element sub-model, a wheelset finite element sub-model, a wheel-rail contact element sub-model, and a support constraint and boundary condition sub-model. Each sub-model has its own functional focus and is coupled with others. The switch area rail finite element sub-model is used to describe in detail the main track structure units of the switch, including the stock rail, switch rail, frog, guard rail, and turnout connection section structure. Its geometric dimensions and node divisions need to be accurately constructed based on engineering drawings or measurement data, and the mechanical parameters of the rail material, such as density, elastic modulus, and Poisson's ratio, should be assigned. The wheelset finite element sub-model is used to express the static mechanical properties of the wheelset, including the mass distribution, geometric features, and mechanical parameters of components such as the wheel tread, flange, and axle. The wheel-rail contact element sub-model describes the contact mechanics characteristics between the wheelset tread and the rail contact surface in the switch area. It requires defining the contact pair, contact stiffness, friction characteristics, and contact tracking algorithm to ensure that the wheel-rail contact state reflects the actual physical behavior in real time during the static solution process. The support constraint and boundary condition sub-model is mainly used to apply various support boundary conditions to the rail model, including end-fixed and simply supported sections, and is used to set the degree-of-freedom constraints for the wheelset model, such as suppressing unreasonable rigid body motion of the wheel in non-rotational degrees of freedom directions.

[0040] After completing the construction of the wheel-rail finite element model in the switch area, gravity loads should be applied to the model according to preset rules to form a physically realistic initial static state. The specific rules for applying the loads are as follows: First, the static vertical gravity load corresponding to the wheelset and sprung mass is applied to the wheel nodes of the wheelset finite element sub-model according to preset working condition parameters. The magnitude of this static load must be equivalent to the self-weight borne by the wheelset under actual working conditions, and should be reasonably distributed according to the symmetrical or asymmetrical distribution of the left and right wheel masses to form the initial static load of the wheelset acting on the rail surface. After the initial static load of the wheelset acting on the rail surface in the switch area is applied, support boundary constraints need to be applied to the rail finite element sub-model in the switch area to fix the end and intermediate support positions of the rail model. These boundary constraints should accurately reflect the support stiffness of the rail provided by the track bed, sleepers, fasteners, etc. in actual engineering, to prevent rigid body drift or non-physical deformation in the simulation. Next, after the rail boundary constraints are applied, the wheel-rail contact element sub-model is activated, enabling the wheel-rail contact elements to naturally transfer the wheelset static load to the rail surface through nodal contact forces, forming a physically closed load transfer chain. At this point, the wheel-rail finite element model of the switch area with applied gravity loads and boundary constraints is obtained.

[0041] To generate the initial static displacement field, static equilibrium calculations must be performed on the wheel-rail finite element model of the switch area, which has been subjected to gravity loads and boundary constraints. The main purpose of the static equilibrium calculation is to solve for the equilibrium displacements and stress states of each node under the conditions of satisfying boundary conditions and external loads. The specific solution steps include: First, generating the initial static loads on the wheel nodes in a static state based on the vertical gravity loads applied to the wheelset finite element sub-model. These initial static loads must be numerically consistent with the physical self-weight to form the correct initial force state. Then, limiting the degrees of freedom of the boundary nodes in the rail finite element sub-model based on the support boundary constraints to prevent the overall rigid body drift of the rail model or numerical non-convergence due to insufficient constraints. On this basis, the static equilibrium solution is performed on the entire wheel-rail finite element model of the switch area, and the initial equilibrium displacements of the wheelset nodes and rail nodes under the combined action of gravity loads and support constraints are obtained through finite element static iterative calculations. During the solution process, key parameters such as normal force, tangential force, contact stiffness, and contact area at each contact point of the wheel-rail contact unit should be monitored in real time to determine whether the contact state has reached physical convergence. Only when the rate of change of normal force and contact stiffness at each contact point is lower than the preset convergence threshold, and the changes in nodal displacement and stress tensor tend to stabilize, can it be determined that the static equilibrium state has converged.

[0042] The nodal displacement vectors, nodal stress tensors, and wheel-rail contact force states obtained under the convergence conditions of static equilibrium solution are used as the initial static displacement field for subsequent steps such as applying initial angular velocities, solving for quasi-steady-state solutions, and generating dynamic relaxation files. The generated initial static displacement field can completely represent the physical equilibrium state of the wheel-rail system in the switch area under its own weight and boundary supports, realistically reflecting the multi-point contact, spatially asymmetric contact state, and wheel-rail force distribution characteristics in the switch area, providing high-precision initial input for subsequent transient dynamic simulations.

[0043] By employing the aforementioned loading and solution rules, the physical consistency and numerical stability of the initial state of the wheel-rail finite element model in the switch area can be effectively guaranteed, avoiding problems such as simulation disturbances, convergence difficulties, or energy non-conservation caused by unreasonable initial condition settings. Simultaneously, this process monitors the changes in wheel-rail contact state in real time during the solution process, effectively capturing and analyzing the multi-point contact force distribution patterns and stress response characteristics of track components in the switch area, providing a reliable data foundation for switch area safety analysis, fatigue life prediction, and structural optimization design.

[0044] Step S20: Apply an initial angular velocity to the wheelset based on the initial static displacement field, and determine the asymmetric quasi-steady-state solution under the wheel-rail structure contact characteristics in the switch area based on the initial angular velocity application result.

[0045] Specifically, based on the initial static displacement field, the target initial angular velocity is applied to the axle rotational degrees of freedom of the wheelset finite element sub-model, and the target initial angular velocity is simultaneously applied to the rotational degrees of freedom of each wheel in the wheelset. During the application of the initial angular velocity, based on the wheel-rail structure contact characteristics in the switch area, the centrifugal force field under the action of the wheelset rotational inertia is solved in real time, and the wheel-rail contact parameters of each contact point of the wheel-rail contact unit are determined to obtain the asymmetric quasi-steady-state contact state. Based on the asymmetric quasi-steady-state contact state, the physical field parameters of the asymmetric quasi-steady-state contact state are continuously monitored until the contact stress state converges. The physical field parameters of the asymmetric quasi-steady-state contact state under the converged state are taken as the asymmetric quasi-steady-state solution.

[0046] Specifically, the wheel-rail contact parameters of each contact point of the wheel-rail contact unit include any one or more of the following: normal force, tangential force, contact stiffness, and contact area distribution at each contact point; the physical field parameters of the asymmetric quasi-steady-state contact state include any one or more of the following: wheel-rail contact point stress, nodal stress tensor, nodal displacement vector, and wheel-rail contact force state.

[0047] In this embodiment of the invention, applying an initial angular velocity to the wheelset based on the initial static displacement field, and determining the asymmetric quasi-steady-state solution under the wheel-rail structural contact characteristics in the switch area based on the initial angular velocity application result, is a crucial step in achieving physical consistency in the wheel-rail simulation of the switch area and reasonable loading of the dynamic initial state. This process requires, on the basis of an established static equilibrium state, introducing the rotational inertia of the wheelset and the corresponding centrifugal force effect through a physically reasonable angular velocity loading method, thereby forming an asymmetric quasi-steady-state contact state that conforms to the complex contact characteristics of the switch area.

[0048] In practice, the initial target angular velocity should first be applied to the axle rotational degrees of freedom of the wheelset finite element sub-model based on the initial static displacement field to drive the wheels to rotate around the axle. This initial target angular velocity value should be determined according to the target operating conditions, design speed, or actual measurement data, and the smoothness and physical consistency of the loading process should be ensured to prevent simulation disturbances or numerical non-convergence caused by abrupt loading. Simultaneously with applying the axle angular velocity, the initial target angular velocity should also be synchronously applied to the rotational degrees of freedom of each wheel in the wheelset to ensure that the axle and wheels rotate as a whole, conforming to the actual dynamic behavior of the wheelset. The loading step size, loading time, and loading method of the angular velocity application should be gradually increased in conjunction with the convergence characteristics of the numerical solver and the physical conditions. A multi-step loading strategy is recommended instead of applying the target angular velocity in one step to improve numerical stability.

[0049] During the application of the initial angular velocity, the centrifugal force field under the rotational inertia of the wheelset should be solved in real time. The centrifugal force calculation needs to be based on parameters such as wheel speed, nodal mass distribution, and nodal radius position, ensuring that it gradually establishes itself and is transmitted to the wheel-rail contact interface as the speed increases. The introduction of centrifugal force will directly change the wheel-rail contact state, causing contact parameters such as the force, contact stiffness, and contact area at the wheel-rail contact point to dynamically adjust with changes in speed. During this process, the wheel-rail contact parameters at each contact point of the wheel-rail contact unit should be determined in real time using the wheel-rail contact unit. These contact parameters should include at least one or more of the following: normal force, tangential force, contact stiffness, and contact area distribution at each contact point, used to comprehensively characterize the mechanical state and spatial distribution characteristics of the wheel-rail contact.

[0050] As the angular velocity loading progresses, under the influence of rotational inertia and centrifugal force, the wheel-rail system gradually establishes a quasi-steady-state contact state that conforms to the characteristics of multi-point contact, gauge variation, and spatial asymmetry in the switch area. At this point, the physical field parameters of this asymmetric quasi-steady-state contact state should be continuously monitored to ensure that the loading process is physically reasonable and convergent. Specifically monitored physical field parameters include one or more of the following: wheel-rail contact point stress, nodal stress tensor, nodal displacement vector, and wheel-rail contact force state. These parameters can be used to determine whether the contact force, nodal stress, and overall displacement field have stabilized and whether the rate of change has met the preset convergence threshold. When the variation amplitude of the above physical field parameters is below the threshold in multiple consecutive loading steps, the asymmetric quasi-steady-state contact state can be considered to have converged.

[0051] The physical field parameters of the asymmetric quasi-steady-state contact state under convergence conditions are used as the asymmetric quasi-steady-state solution, serving as the high-precision initial input for subsequent dynamic relaxation file generation or transient dynamic solution of the target working condition. The asymmetric quasi-steady-state solution can fully reflect the physical equilibrium state of the wheel-rail system in the switch area after initial angular velocity and rotational inertia loading, accurately describing the multi-point contact force distribution, spatial asymmetric contact relationship, and force response characteristics of track components, providing a physically consistent foundation for subsequent dynamic simulation.

[0052] By employing the aforementioned process of applying initial angular velocity and determining the asymmetric quasi-steady-state solution, numerical shock problems caused by directly applying angular velocity or target rotational speed can be effectively avoided. This ensures that the dynamic establishment of wheel-rail contact state, centrifugal force effect, and internal stress distribution conforms to actual physical laws. Simultaneously, real-time monitoring of wheel-rail contact parameters and physical field changes during loading helps identify potential numerical problems early in the simulation, allowing for timely adjustments to the loading strategy, improving numerical convergence and simulation accuracy, and providing a solid data foundation for switch area safety analysis, fatigue life prediction, and structural optimization design.

[0053] In another possible implementation, to improve the physical consistency and convergence stability of the initial loading in the three-dimensional wheel-rail contact simulation of the switch area, this embodiment adopts a combination of a segmented incremental angular velocity loading strategy and localized intensified monitoring of the contact area to determine the asymmetric quasi-steady-state solution under the wheel-rail structural contact characteristics of the switch area. The specific steps include: First, based on the initial static displacement field obtained from the static equilibrium solution, the target initial angular velocity is applied segmentally to the axle rotational degrees of freedom of the wheelset finite element sub-model in increments of 10%, while simultaneously loading the rotational degrees of freedom of each wheel in the wheelset. After each loading segment, the change in the centrifugal force field caused by the rotational inertia of the wheelset is solved in real time to update the contact force state of the wheel-rail contact unit.

[0054] Unlike the conventional approach of applying the target angular velocity all at once, this embodiment introduces a localized, intensified monitoring mechanism for the contact areas of key track components (such as the frog nose and the movable end of the switch rail) in the switch zone while simultaneously applying the angular velocity in segments. Specifically, at the contact points in these areas, changes in normal force, tangential force, contact stiffness, and local nodal stress are recorded with higher temporal accuracy to dynamically assess the stability of the local contact state. Only when the rate of change of these key contact points is below a preset threshold, and the global contact force state and nodal stress field converge, is an asymmetric quasi-steady-state contact state determined to have been established, and the physical field data at the convergence moment is saved as the asymmetric quasi-steady-state solution.

[0055] This embodiment achieves a gradual transition of the physical process and enhanced monitoring of key parts during angular velocity loading, effectively suppressing local disturbances during rotational inertia loading, improving the physical authenticity and numerical stability of the asymmetric quasi-steady-state solution, and providing better initial conditions for high-precision wheel-rail dynamics analysis in the switch area.

[0056] Step S30: Generate a dynamic relaxation file based on the asymmetric quasi-steady-state solution to record the steady-state displacement and stress state of each node in the switch region.

[0057] Specifically, the physical field parameters of each node in the asymmetric quasi-steady-state solution are classified according to node number to obtain multiple datasets, and a quasi-steady-state data structure containing complete physical field states is formed based on each dataset; the quasi-steady-state data structure is recorded in a dynamic relaxation file format to obtain an initial dynamic relaxation file; wherein, each data entry in the dynamic relaxation file format includes the spatial position, steady-state displacement, steady-state stress, steady-state strain of the corresponding node and the wheel-rail contact parameters of the corresponding contact point; the generated initial dynamic relaxation file is subjected to consistency verification, and a dynamic relaxation file that passes the consistency verification is output.

[0058] In this embodiment of the invention, generating a dynamic relaxation file based on the asymmetric quasi-steady-state solution to record the steady-state displacement and stress state of each node in the switch region is a crucial step in ensuring high-precision initial conditions for the transient dynamic simulation of the switch region. In practice, this process not only requires the complete preservation of the physical field information of the asymmetric quasi-steady-state solution but also ensures a reasonable data structure, standardized format, and consistent content to facilitate efficient loading and calling by the solver. Specific operational rules need to be implemented gradually to ensure that the data generation process is scientific, standardized, and controllable.

[0059] Based on the asymmetric quasi-steady-state solution, the physical field parameters of each node are categorized and organized according to node number, ensuring that the data corresponds one-to-one in spatial order and number sequence, without omissions or confusion. These physical field parameters include at least the spatial location, steady-state displacement, steady-state stress tensor, and steady-state strain tensor of each node. For contact nodes located in wheel-rail contact elements, the corresponding wheel-rail contact parameters should also be included. The wheel-rail contact parameters should at least cover the normal force, tangential force, contact stiffness, and contact area of ​​the contact point, comprehensively expressing the force and contact behavior characteristics of the node under quasi-steady-state contact conditions. During the classification and organization process, a hierarchical, unit-based node data grouping method is recommended. That is, first divide by sub-models (such as rail elements, wheelset elements, and contact elements), and then sort by node number. This facilitates subsequent file structure organization and inspection.

[0060] After classifying and organizing the node data, a quasi-steady-state data structure should be constructed based on the classification results, forming a set of node information containing complete physical field states. This data structure needs to ensure accurate reconstruction of the physical field states of the asymmetric quasi-steady-state solution in spatial distribution. Therefore, each data entry should include the node spatial position vector, steady-state displacement vector, steady-state stress tensor, steady-state strain tensor, and wheel-rail contact parameters (if the node is a contact node). The format of the data structure must conform to the requirements of the solver for calling the dynamic relaxation file format, ensuring that the node data is strictly consistent with the physical position and contact state when the file is loaded.

[0061] The quasi-steady-state data structure is recorded in a dynamic relaxation file format to generate an initial dynamic relaxation file. The dynamic relaxation file format requires each data entry to be complete and standardized, including not only node numbers and spatial coordinates, but also complete records of the node's steady-state displacement, steady-state stress, steady-state strain, and contact parameter values. The file recording format is generally text or binary structured data; the specific data precision (e.g., six or eight decimal places) can be set according to the solver requirements to ensure that the accuracy of the recorded physical parameters meets the requirements of high-speed wheel-rail contact simulation.

[0062] After generating the initial dynamic relaxation file, a consistency check should be performed. The check can be performed as follows: First, check if each node's data entry is complete and if there are any missing items or format errors; second, compare the node data with the original data of the asymmetric quasi-steady-state solution to prevent numerical errors introduced during data recording due to truncation, format conversion, or sorting; finally, verify if the contact parameters of the contact node data are consistent with the monitoring results in the asymmetric quasi-steady-state solution to ensure the completeness and accuracy of the contact state information. Only when the consistency check passes—that is, the file data is complete, the accuracy is acceptable, and the content is consistent—can the final dynamic relaxation file for transient dynamics solving be output.

[0063] Step S40: Load the dynamic relaxation file as the initial state, perform a simulation of the wheelset passing through the switch zone, and output the real-time dynamic response results.

[0064] Specifically, the physical field parameters recorded in the dynamic relaxation file are loaded into the wheel-rail finite element model of the switch area after the gravity load is applied, as the initial conditions for simulation to simulate the process of the wheelset passing through the switch area; during the simulation, the dynamic response of the wheel-rail finite element model of the switch area under centrifugal force, wheel-rail contact force and support constraint is solved in real time, and the dynamic response parameters of each wheel and rail are output in real time as the real-time dynamic response results.

[0065] Specifically, the wheel-rail dynamic response parameters include any one or more of the following: wheelset displacement time history, wheel-rail contact force time history, nodal stress variation, hourglass energy variation, and internal energy variation.

[0066] In this embodiment of the invention, loading the dynamic relaxation file as the initial state, performing a simulation of the wheelset passing through the switch zone, and outputting real-time dynamic response results are key steps in the wheel-rail simulation method for the switch zone. The goal of this step is to simulate the dynamic behavior of the wheelset throughout the entire process of passing through the switch zone based on a complete and consistent initial physical state, ensuring that the simulation results accurately reflect the dynamic response characteristics of the wheel-rail system under actual operating conditions. To achieve this goal, the loading and solving process must have clear logical steps and strict operating procedures.

[0067] The physical parameters recorded in the dynamic relaxation file should be loaded into the wheel-rail finite element model of the switch area after the application of gravity load, and used as the initial conditions for simulation. These physical parameters include the spatial position of each node, the nodal displacement vector under initial static equilibrium, the nodal stress tensor, the strain tensor, and the contact parameters of each wheel-rail contact point, such as normal force, tangential force, contact stiffness, and contact area. The loading of these parameters should strictly correspond to the node number and physical position to ensure that the file data matches the nodes of the finite element model one by one. There should be no misalignment of numbers or incorrect correspondence of physical positions to prevent rigid body drift, non-physical deformation, or local numerical instability during the simulation.

[0068] After loading the dynamic relaxation file data, a simulation of the wheelset passing through the switch area is performed based on these initial conditions. The simulation process must be based on explicit or implicit dynamic solution methods, solving the dynamic response of the wheel-rail finite element model in the switch area under the combined effects of centrifugal force, wheel-rail contact force, and support constraints in real time. The calculation of centrifugal force should be updated in real time in conjunction with the wheel set angular velocity, nodal mass, and nodal radial position; the solution of wheel-rail contact force should be based on the real-time calculation of the changes in normal and tangential forces at the contact points using contact elements; the support constraints must remain active throughout the entire dynamic solution to ensure the stability of the track structure. During the dynamic solution process, the solution accuracy of each physical field parameter should meet the requirements of high-speed wheel-rail simulation for both temporal and spatial resolution. It is recommended to select time step settings and solver parameters suitable for high-speed dynamic simulation.

[0069] Simultaneously with the solution process, the dynamic response parameters of each wheel and rail should be output in real time as the real-time dynamic response results. These dynamic response parameters include at least one or more of the following: wheelset displacement time history, wheel-rail contact force time history, nodal stress variation, hourglass energy variation, and internal energy variation. The wheelset displacement time history can be used to analyze the trajectory changes of the wheelset during its passage through the switch area; the wheel-rail contact force time history is used to monitor the temporal variation characteristics of the wheel-rail interaction force and analyze the fluctuation of the wheel-rail contact load; the nodal stress variation can be used to evaluate the stress distribution and variation trend of the track structure and wheelset during the passage through the switch area; the hourglass energy variation and internal energy variation are used to analyze energy dissipation, local energy accumulation, and energy conservation in the solution process to determine the numerical stability and convergence of the simulation.

[0070] By applying the above rules, it can be ensured that the simulation of the entire wheelset passing through the switch area can completely reproduce the physical behavior under actual working conditions, achieving high-precision solution and high-reliability output of the wheel-rail dynamic response in the switch area. This method avoids simulation deviations and numerical instability caused by inconsistent initial conditions or incomplete loading of physical parameters, ensuring the engineering applicability and scientific analysis value of the simulation results, and providing a solid numerical foundation for subsequent work such as switch area safety analysis, structural optimization design, and fatigue life assessment.

[0071] In one possible implementation, during the transition of the wheel from static to dynamic rolling, radial displacement and stress may exacerbate the initial disturbance, especially during high-speed train operation. This can lead to a longer "dynamic relaxation zone" required for stable contact, significantly reducing computational efficiency. To effectively address this issue, the improved method applies an initial angular velocity to the wheelset during implicit static analysis to obtain displacement, stress, and strain results under the influence of gravity. These results are then used as the initial conditions for implicit calculations, thereby improving computational efficiency. The specific steps are as follows:

[0072] Static calculations—gravity loads: In stage 1, gravity loads are first applied to the entire wheel-rail model of the switch area (see...). Figure 2 Step 1). In this stage, the track geometry and wheel-track contact state are accurately modeled, including track geometry variations in the switch area, to ensure the accuracy of the calculations.

[0073] Approximate Steady-State Calculation—Superimposed Wheelset Rotational Inertia: Based on the calculation results obtained from the gravitational acceleration applied in Stage 1, the rotational angular velocity of the wheelset is superimposed to calculate the steady-state response of the entire wheel-rail system in the switch area (see...). Figure 2 Step 2). Because the contact points between the wheels on both sides of the wheelset and the straight and curved main rails of the switch are not symmetrical along the center line of the track, under the rotational inertia of the wheelset, there will be asymmetry in contact displacement and contact stress between the wheelset and the switch rail.

[0074] Calculate the initial displacement field—generate a dynamic relaxation file: Based on the quasi-static results of gravitational acceleration and wheelset rotation speed obtained in stage 2, calculate the total displacement of each node in the model. This displacement is generated by the superposition of gravity and rotational inertia, and generate a dynamic relaxation file containing displacement and stress results.

[0075] Transient dynamics calculation—applying initial translational and rotational velocities: In the dynamics calculation stage of phase 4, all nodes of the entire model are first loaded with the displacement results obtained from the dynamic relaxation file using the dynamic relaxation method. Then, the initial velocities of the wheelset and sprung mass are set before the wheels roll at high speed. During this process, considering the changes in track geometry within the switch zone, the dynamic response of the wheelset when passing through the switch is more complex than that of a normal track, making it more difficult to achieve a smooth wheel-rail contact state.

[0076] After the above four stages of calculation, the triaxial displacement results of the wheelset at time t=0 can be obtained from the dynamic calculation, and these results can be updated in the dynamic relaxation file obtained in stage 3. This will further improve the smooth convergence speed of the wheelset.

[0077] For example, such as Figure 2 , Figure 3 and Figure 4This paper analyzes the wheel-rail forces calculated for straight and reverse passage through a switch area at a speed of 350 km / h, comparing the vertical and lateral wheel-rail forces obtained using traditional and improved methods, with a focus on the initial disturbance. For the case of straight and reverse travel through the switch structure, the wheelset interacts with the curved base rail, the straight switch rail, and the straight base rail. The straight base rail makes contact on one side of the wheelset, while the straight switch rail and the curved base rail, in close contact, interact with the other side of the wheelset, resulting in a two-point contact moment. As the wheelset travels, the wheel-rail force on the curved base rail on the combined rail side gradually decreases, while the wheel-rail force on the straight switch rail gradually increases. The calculation results show that the straight base rail calculated using the traditional method has a large initial oscillation, which gradually decreases with increasing travel distance. In contrast, the wheel-rail force on the straight base rail calculated using the improved method is very small in the initial stage. It can be seen that the improved method reaches a relatively stable stage in about 1 ms. The fluctuations between 1 ms and 20 ms may be related to the geometric positional offset of the curved base rail of the switch. The wheel-rail contact point is constantly changing and can be observed. Figure 4 The basic trajectory curve shows a significant decrease followed by stabilization. Figure 5 The straight point rails shown do not show a significant difference because they have stabilized during the preceding period and are no longer affected by the initial excitation.

[0078] Furthermore, such as Figure 5 The initial lateral force of the straight main rail exhibits significant high-frequency fluctuations, which gradually decrease with increasing running distance. While the wheel-rail force of the straight main rail calculated by the improved method also shows fluctuations in the initial stage, the high-frequency components of the fluctuations are significantly weakened, with low-frequency vibrations dominating. This can be observed... Figure 3 The basic trajectory curve shows a significant decrease followed by stabilization. Figure 6 The contrast between the lateral wheel-rail forces on the basic track is not very obvious, which is related to the serpentine motion of the wheelset. (See...) Figure 7 .

[0079] Furthermore, Figure 7 It can be seen that the improved method exhibits a more significant negative displacement around 30ms, while the traditional method does not. After the curve passes the second inflection point, the positive displacement of the improved method is smaller than that of the traditional method. The maximum difference in lateral wheelset movement between the two methods can reach 0.55mm, which also indicates a significant difference in the wheel-rail contact point in the switch area, especially affecting the calculation of the wheel load transition section in the switch area.

[0080] Furthermore, the changes in hourglass energy and internal energy under both methods are analyzed, see [link to analysis]. Figure 8 and Figure 9 . Figure 8The figure shows the hourglass energy and internal energy curves of the switch rail. The hourglass energy and internal energy of the improved method are generally lower than those of the traditional method. Under steady-state energy conditions, the improved method achieves 73.7% of the hourglass energy and 84.3% of the internal energy of the traditional method. Figure 9 The figure shows the hourglass energy and internal energy curves of the wheelset. Unlike the switch structure, the hourglass energy difference for the wheelset is not significant, while the internal energy curve of the traditional method exhibits a relatively obvious oscillation curve. The internal energy of the improved method, however, is very stable, and in the stable state after 20ms, the internal energy of the improved method is 61.9% of that of the traditional method. This also demonstrates that the wheelset's state is unstable under the traditional method, while the improved method of this invention is more reliable, more efficient, and can reach a convergent state more quickly in the wheel-rail dynamics problem of the switch region.

[0081] Furthermore, frequency domain analysis is performed on the oscillation waveform during the initial rolling phase of the traditional method. Figure 10 and Figure 11 These are the frequency spectra of the vertical forces on the straight and curved basic rails, respectively. It can be seen that the traditional method exhibits a very obvious dominant frequency of 3076Hz and 3222Hz, and also a resonant peak at 2832Hz. The improved method, with its more stable calculation results, does not show this peak. This indicates that the traditional method may be generating a non-physical, continuous excitation vibration, related to the numerical calculation algorithm, and cannot reflect the vibration characteristics of the wheel-rail forces excited by the switch structure itself.

[0082] Figure 12 This is a system structure diagram of a three-dimensional wheel-rail contact model simulation system for a switch area provided in one embodiment of the present invention. Figure 12 As shown, this invention provides a simulation system for a three-dimensional wheel-rail contact model in a switch area. The system includes: an initialization unit, used to apply a gravity load to the wheel-rail finite element model of the switch area based on the structural contact characteristics of the switch area, generating an initial static displacement field; a processing unit, used to apply an initial angular velocity to the wheelset based on the initial static displacement field, and determine an asymmetric quasi-steady-state solution under the wheel-rail structural contact characteristics of the switch area based on the initial angular velocity application result; a fitting unit, used to generate a dynamic relaxation file based on the asymmetric quasi-steady-state solution to record the steady-state displacement and stress state of each node in the switch area; and a simulation unit, used to load the dynamic relaxation file as the initial state, perform a simulation of the wheelset passing through the switch area, and output real-time dynamic response results.

[0083] The present invention also provides a computer-readable storage medium storing instructions that, when executed on a computer, cause the computer to perform the above-described simulation method for a three-dimensional wheel-rail contact model of a switch area.

[0084] Those skilled in the art will understand that all or part of the steps in the methods of the above embodiments can be implemented by a program instructing related hardware. This program is stored in a storage medium and includes several instructions to cause a microcontroller, chip, or processor to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as a USB flash drive, a portable hard drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0085] The optional embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the embodiments of the present invention are not limited to the specific details described above. Within the scope of the technical concept of the embodiments of the present invention, various simple modifications can be made to the technical solutions of the embodiments of the present invention, and these simple modifications all fall within the protection scope of the embodiments of the present invention. It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the embodiments of the present invention will not further describe the various possible combinations.

[0086] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the embodiments of the present invention, they should also be regarded as the content disclosed by the embodiments of the present invention.

Claims

1. A method of simulating a three-dimensional wheel-rail contact model of a switch area, characterized by, The method comprises: The method comprises: The switch area wheel-rail finite element model comprises: a switch area rail finite element submodel, a wheelset finite element submodel, a wheel-rail contact element submodel, and a support constraint and boundary condition submodel; the switch area rail finite element submodel is used to describe the switch structure and the turnout connecting section structure; the wheelset finite element submodel is used to describe the static mechanical characteristics of the wheelset; the wheel-rail contact element submodel is used to describe the contact mechanical characteristics of the wheel tread and the switch area rail contact surface; and the support constraint and boundary condition submodel is used to apply support boundary conditions to the switch area rail finite element submodel, and to apply degree of freedom constraint conditions to the wheelset finite element submodel; Based on the initial static displacement field, the initial angular velocity is applied to the wheelset, and the asymmetric quasi-steady state solution under the switch area wheel-rail structural contact characteristics is determined based on the initial angular velocity application result; wherein Based on the initial static displacement field, the initial angular velocity is applied to the wheelset, and the asymmetric quasi-steady state solution under the switch area wheel-rail structural contact characteristics is determined based on the initial angular velocity application result, which comprises: based on the initial static displacement field, a target initial angular velocity is applied to the axle rotation degree of freedom of the wheelset finite element submodel, and the target initial angular velocity is synchronously loaded to the rotation degree of freedom of each wheel in the wheelset; during the initial angular velocity application process, based on the switch area wheel-rail structural contact characteristics, the centrifugal force field under the wheelset rotational inertia is solved in real time, and the wheel-rail contact parameters of each contact point of the wheel-rail contact element are determined to obtain the asymmetric quasi-steady state contact state; based on the asymmetric quasi-steady state contact state, the physical field parameters of the asymmetric quasi-steady state contact state are continuously monitored until the contact stress state converges, and the physical field parameters of the asymmetric quasi-steady state contact state in the converged state are taken as the asymmetric quasi-steady state solution; Based on the asymmetric quasi-steady state solution, a dynamic relaxation file is generated for recording the steady-state displacement and stress state of each node in the switch area; The dynamic relaxation file is loaded as an initial state, the process simulation of the wheelset passing through the switch area is performed, and real-time dynamic response results are output.

2. The method of claim 1, wherein, The rules for applying the gravity load to the switch area wheel-rail finite element model are as follows: The static vertical gravity load corresponding to the wheelset and the sprung mass is applied to the wheel node of the wheelset finite element submodel according to the preset working condition parameters, so as to form the initial static load of the wheelset acting on the switch area rail surface; After the initial static load of the wheelset acting on the switch area rail surface is applied, the support boundary constraint condition is applied to the switch area rail finite element submodel to fix the rail end and the intermediate support point position; After the rail boundary constraint is applied, the wheel-rail contact element submodel is activated to transmit the load of the node to the rail surface through the wheel-rail contact element submodel, and the switch area wheel-rail finite element model with the gravity load applied is obtained.

3. The method of claim 1, wherein, The rules for generating the initial static displacement field are as follows: Performing static equilibrium calculation on the wheel-rail finite element model of the switch area under the gravity load to obtain the initial equilibrium displacement of the wheelset node and the rail node under the combined action of the gravity load and the support constraint; During the static equilibrium calculation, the normal force, tangential force and contact stiffness of each contact point of the wheel-rail contact unit are monitored in real time until the static equilibrium state converges, and the node displacement vector, node stress tensor and wheel-rail contact force state under the convergence condition are obtained; The obtained node displacement vector, node stress tensor and wheel-rail contact force state are used as the initial static displacement field.

4. The method of claim 1, wherein, The wheel-rail contact parameters of each contact point of the wheel-rail contact unit include: Any one or more of the normal force, tangential force, contact stiffness and contact area distribution of each contact point; The physical field parameters of the asymmetric quasi-steady state contact state include: Any one or more of the wheel-rail contact point stress, node stress tensor, node displacement vector and wheel-rail contact force state.

5. The method of claim 1, wherein, Based on the asymmetric quasi-steady state solution, a dynamic relaxation file for recording the steady-state displacement and stress state of each node of the switch area is generated, including: Classifying the physical field parameters of each node in the asymmetric quasi-steady state solution according to the node number to obtain a plurality of data sets, and forming a quasi-steady state data structure containing the complete physical field state based on each data set; The quasi-steady state data structure is recorded in the dynamic relaxation file format to obtain an initial dynamic relaxation file; wherein, Each data entry in the dynamic relaxation file format contains the spatial position, steady-state displacement, steady-state stress, steady-state strain of the corresponding node, and the wheel-rail contact parameter of the corresponding contact point; Performing consistency check on the generated initial dynamic relaxation file, and outputting the dynamic relaxation file that passes the consistency check.

6. The method of claim 1, wherein, Loading the dynamic relaxation file as the initial state, performing process simulation of the wheelset passing through the switch area, and outputting the real-time dynamic response result, including: Loading each physical field parameter recorded in the dynamic relaxation file into the wheel-rail finite element model of the switch area after the gravity load is applied as the simulation initial condition to perform process simulation of the wheelset passing through the switch area; During the simulation process, the dynamic response of the wheel-rail finite element model of the switch area under the action of the centrifugal force, wheel-rail contact force and support constraint is solved in real time, and each wheel-rail dynamic response parameter is output in real time as the real-time dynamic response result.

7. The method of claim 6, wherein, Each wheel-rail dynamic response parameter includes: Any one or more of the wheelset displacement time history, wheel-rail contact force time history, node stress change value, hourglass energy change value and internal energy change value.

8. A system for simulating a three-dimensional wheel-rail contact model of a switch area, characterized by The system is used to perform the switch area three-dimensional wheel-rail contact model simulation method of any one of claims 1-7, and the system includes: An initial unit for applying a gravity load to the wheel-rail finite element model of the switch area based on the structural contact characteristics of the switch area to generate an initial static displacement field; A processing unit for performing initial angular velocity application on the wheelset based on the initial static displacement field, and determining an asymmetric quasi-steady state solution under the structural contact characteristics of the wheel-rail of the switch area based on the initial angular velocity application result; A fitting unit for generating a dynamic relaxation file for recording the steady-state displacement and stress state of each node of the switch area based on the asymmetric quasi-steady state solution; An analog unit is used to load the dynamic relaxation file as an initial state, execute process simulation of wheel set passing through a switch area, and output real-time dynamic response results.

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