A temperature and train coupled vehicle-track interaction simulation method

Abstract

The application provides a vehicle-track interaction simulation method coupled with temperature and trains. The method comprises: establishing a track structure thermal coupling analysis model by using a finite element method, calculating a spatial temperature field and temperature deformation of the track structure; establishing a vehicle-rail coupling submodel based on self-programming; establishing a ballastless track bed submodel considering complex temperature effects based on the track structure thermal coupling analysis model; the ballastless track bed submodel and the vehicle-rail coupling submodel interact with each other in real time through a data interaction interface, and the dynamic characteristics of the vehicle-track system under the coupling action of temperature and trains are calculated. The application analyzes the advantages and disadvantages of the simulation model, and proposes a vehicle-track interaction simulation method coupled with temperature and trains, which can simultaneously consider the spatial temperature effect of the ballastless track under the action of temperature and the dynamic characteristics of the vehicle-track coupling system, and improves the accuracy of the calculation model.

Description

Technical Field

[0001] This invention relates to the field of vehicle-track interaction technology, and more particularly to a simulation method for vehicle-track interaction involving temperature and train coupling. Background Technology

[0002] Currently, for the simulation of vehicle-track interaction under temperature and train load, scholars at home and abroad mainly use self-programmed development and general-purpose finite element software for simulation.

[0003] For simulation methods developed using self-programming techniques, development costs are high, and the models often undergo significant simplification, making it difficult to accurately account for the spatial temperature field and temperature deformation of ballastless tracks. Currently, existing vehicle-track dynamics simulation methods under temperature and train loads include: some schemes study the stress and deformation of ballastless tracks at high speeds, then superimpose rail irregularities caused by high temperatures to study the system's dynamic characteristics. Other schemes input track irregularities generated by temperature effects into the vehicle-track-bridge analysis model to study the system's dynamic response under different temperature loads. This approach uses temperature-induced track irregularities superimposed on the track irregularities as the system's excitation source, neglecting the nonlinearity of track structure stiffness irregularities and interlayer contact states caused by temperature effects.

[0004] Regarding methods utilizing general-purpose finite element software, one approach uses Abaqus to establish a vehicle-track dynamics model, analyzing the vibration characteristics of the system and the stress on the track slab under different temperature gradients. Another approach uses the general-purpose finite element software ANSYS to establish a train-track coupled dynamics model considering the temperature effect. However, it is difficult to accurately simulate the wheel-rail contact relationship in finite element software, resulting in poor vibration prediction accuracy for structures such as rails and an inability to accurately reflect the vibration of the coupled system.

[0005] The disadvantages of the existing vehicle-track dynamics simulation methods under temperature and train load conditions mentioned above include: (1) The self-programming development method is time-consuming and costly, and it is currently difficult to accurately simulate the temperature effect of ballastless track space. In addition, this method is difficult to effectively simulate the nonlinearity of track structure stiffness and interlayer contact state caused by temperature effect.

[0006] (2) Although the complex temperature effect of the track structure can be considered with the help of general finite element software, it is difficult to accurately simulate the wheel-rail contact, resulting in poor prediction accuracy of the vibration of the rail and other structures, and thus it is difficult to accurately reflect the vibration of the coupled system. Summary of the Invention

[0007] The embodiments of the present invention provide a simulation method for vehicle-track interaction under temperature and train coupling, so as to achieve a refined simulation of vehicle-track interaction under the action of temperature and train coupling.

[0008] To achieve the above objectives, the present invention adopts the following technical solution.

[0009] A simulation method for vehicle-track interaction coupled with temperature and train characteristics, comprising: A thermo-mechanical coupling analysis model of ballastless track was established using the finite element method to calculate the spatial temperature field and temperature deformation of the track structure. A vehicle-rail coupling sub-model was built based on self-programming. Based on the aforementioned thermo-mechanical coupling analysis model of ballastless track, a sub-model of ballastless track bed considering complex temperature effects is established; The ballastless track sub-model interacts with the vehicle-rail coupling sub-model in real time through a data interaction interface to calculate the dynamic characteristics of the vehicle-track system under temperature and train coupling.

[0010] Preferably, the step of establishing a thermo-mechanical coupling analysis model of the ballastless track using the finite element method to calculate the spatial temperature field and temperature deformation of the track structure includes: A thermo-mechanical coupling analysis model for ballastless track was established using the finite element method. This model includes a continuous medium model of rails, fasteners, track slabs, self-compacting concrete, and base plate. The rails directly bear the wheel-rail impact load and are simulated by periodically discrete Timoshenko beams to simulate vertical, lateral bending, torsion, and axial vibrations. The fasteners are simulated using triaxial spring-damping elements, and the fastener forces are evenly distributed to the track slab through distributed coupling. The track slab, self-compacting concrete, and base plate are all simulated using solid elements. The surface boundary conditions and interlayer contact conditions of the thermal coupling analysis model of the ballastless track satisfy the basic principles of heat transfer. Based on geographical and meteorological data, the comprehensive atmospheric temperature and overall heat transfer coefficient of each structural surface are calculated using heat transfer analysis theory, and the spatial temperature field and temperature deformation of the track structure are calculated.

[0011] Preferably, the method of establishing a vehicle-rail coupling sub-model based on self-programming includes: A vehicle-rail coupled sub-model was established based on self-programming. This sub-model considers the vibration of various vehicle components and the rail. The rail is simulated using a discretely supported Timoshenko beam. The dynamic equations of the rail are solved using the modal superposition method. The motion equations of the vehicle and the rail are as follows: (1) (2) in (3) In the formula , and These are the mass, stiffness, and damping matrices, respectively, with subscripts v and r representing the vehicle and rail, respectively. , and These are displacement, velocity, and acceleration vectors, respectively. and These are the vehicle's weight vector and the wheel-rail force vector, respectively. , and These are the generalized mass, damping, and stiffness matrices of the rail, respectively. The front reserved for the rails n The first-order free mode matrix; The modal frequency of the rail; and These are the displacement vectors in the physical and modal spaces of the rail, respectively. It is the generalized load force vector of the fasteners borne by the rail.

[0012] Normal force in the wheel-rail force vector It is determined by Hertz's nonlinear elastic contact theory and is expressed as:

[0013] Where G is the wheel-rail contact constant. The track is uneven. It is time t. j Vertical displacement of the wheel set It is time t. j Vertical displacement of the rail at the position of the wheel set; The tangential creep force was corrected by introducing a correction coefficient using the Shen-Hedrick-Elkins model, resulting in the corrected wheel-rail longitudinal creep force. Lateral creep force and rotational creep force Expressed as:

[0014] in The wheel-rail creep coefficient, , and These are the longitudinal, lateral, and spin creep rates of the wheel-rail system, respectively. For correction factor, , and These are the longitudinal creep force, lateral creep force, and rotational creep force of the wheel and rail before correction.

[0015] Preferably, the establishment of a ballastless track sub-model considering complex temperature effects based on the thermo-mechanical coupling analysis model of the ballastless track includes: Based on the aforementioned thermo-mechanical coupling analysis model of ballastless track, a sub-model of the ballastless track bed considering complex temperature effects is established using finite element software. This sub-model considers the vibration of the track slab, self-compacting concrete, and base slab. The thermo-mechanical coupling analysis results of the aforementioned model are used as the initial boundary conditions for the sub-model. The equations of motion for the sub-model are as follows: (6) In the formula , and These represent the mass, stiffness, and damping matrices of the ballastless track bed. , and These are the displacement, velocity, and acceleration vectors of the ballastless track bed, respectively. This represents the temperature-dependent stiffness matrix. This represents the initial displacement of the structure caused by thermal strain. Indicates the equivalent load of thermal stress. It is the load vector of the fasteners borne by the ballastless track bed.

[0016] Preferably, the ballastless track sub-model interacts with the vehicle-rail coupling sub-model in real time via a data interaction interface to calculate the dynamic characteristics of the vehicle-track system under temperature and train coupling effects, including: The ballastless track sub-model uses a data interaction interface built through secondary development of finite element software. This sub-model interacts with the vehicle-rail coupling sub-model in real time to calculate data. The vibration of the vehicle-rail coupling sub-model is solved using explicit dynamics, while the vibration of the ballastless track sub-model is solved using implicit dynamics. The vehicle-rail coupling sub-model uses a small time step, while the ballastless track sub-model uses a large time step. The large and small time steps can be expressed as: (7) in and The first i Large time steps and small time steps of a moment For the first i-1 The large time step of a moment, For the initial small time step, and These are large time steps and small time steps, respectively. m times ; Within a single large time step, the computation steps include: (1) The calculation result of the above large time step is used as the initial state of the current large time step. It is assumed that in the current large time step... The fastening force and large time step of the ballastless track bed model Equal to each other, solve equation (6) to obtain the dynamic response of the ballastless track bed sub-model; (2) Based on the dynamic response calculation of the track slab, the fastening force on the vehicle-rail coupled sub-model at small time steps is calculated, and the fastening force on the vehicle-rail coupled sub-model at different times is obtained by linear interpolation. By solving equations (1)-(2) step by step, the dynamic response of the vehicle-rail coupling sub-model within a small time step is obtained. (3) Solve for the fastener force based on the dynamic response of the rail and track slab at the end of the large time step. This fastener force is used as the initial fastener force for the next large time step. Repeat the above steps to solve for the dynamic response of the coupled system. The deformation and stress state of the track structure under the action of temperature field are calculated based on the thermo-mechanical coupling analysis model of ballastless track. The track irregularity is updated based on the deformation of the rail. In each analysis step, the irregularity amplitude of each wheel-rail contact point is determined according to the position of the train on the track and the response results of the vehicle and the track in the previous analysis step. Based on the wheel-rail contact geometry, the wheel-rail vertical force and creep force are calculated. The data is interactively calculated in real time with the vehicle-rail interaction model using a data interaction interface. The fastener force in each time step is calculated by interacting with the displacement and velocity of the rail and the track slab to obtain the wheel-rail interaction force and the fastener force. The dynamic response of the vehicle and the rail is obtained by explicit integration algorithm and the dynamic response of the ballastless track bed is obtained by implicit integration method. The above process is continuously repeated until the vehicle runs out of the temperature effect section.

[0017] As can be seen from the technical solutions provided by the embodiments of the present invention above, the present invention, by analyzing the advantages and disadvantages of the above simulation models, proposes a vehicle-track interaction simulation model that couples temperature and train, which can simultaneously consider the spatial temperature effect of ballastless track under temperature action and the dynamic characteristics of the vehicle-track coupling system, thereby improving the accuracy of the calculation model.

[0018] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and will become apparent from the description or may be learned by practice of the invention. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 A flowchart illustrating a simulation method for vehicle-track interaction involving temperature and train coupling, provided in an embodiment of the present invention. Figure 2 A thermo-mechanical coupling analysis model diagram of ballastless track based on the finite element method is provided in an embodiment of the present invention; Figure 3 A vehicle-track interaction model diagram of temperature and train coupling, established based on a combination of self-programming and general-purpose finite element software, is provided for an embodiment of the present invention. Figure 4 A flowchart illustrating the application of a vehicle-track interaction model provided in an embodiment of the present invention; Figure 5 This invention provides a simulation method for verifying vehicle-track interaction under temperature and train coupling conditions. Figure 6 This is a comparison chart of measured and simulated acceleration of a track slab at different times of day, provided as an embodiment of the present invention. Detailed Implementation

[0021] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0022] Those skilled in the art will understand that, unless specifically stated otherwise, the singular forms “a,” “an,” “the,” and “the” used herein may also include the plural forms. It should be further understood that the term “comprising” as used in this specification means the presence of the stated features, integers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. It should be understood that when we say an element is “connected” or “coupled” to another element, it can be directly connected or coupled to the other element, or there may be intermediate elements. Furthermore, “connected” or “coupled” as used herein can include wireless connections or couplings. The term “and / or” as used herein includes any and all combinations of one or more of the associated listed items.

[0023] It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the same meaning as in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless defined as herein.

[0024] To facilitate understanding of the embodiments of the present invention, several specific embodiments will be further explained below with reference to the accompanying drawings, and these embodiments do not constitute a limitation on the embodiments of the present invention.

[0025] This invention proposes a simulation method for vehicle-track interaction coupled with temperature and train based on a combination of self-programming and general-purpose finite element software. It fully considers the spatial temperature effect of ballastless track in natural environment, and can also accurately reflect the interaction between vehicle and track, thus realizing a refined simulation of vehicle-track interaction coupled with temperature and train.

[0026] The processing flow of a vehicle-track interaction simulation method for temperature and train coupling provided in this embodiment of the invention is as follows: Figure 1 As shown, the processing steps include the following: Step S10: Establish a thermo-mechanical coupling analysis model for ballastless track using the finite element method.

[0027] Step S20: Based on the thermal coupling analysis model of ballastless track, a vehicle-rail coupling sub-model is established using self-programming. Based on the thermal coupling analysis model of ballastless track, a ballastless track bed sub-model considering complex temperature effects is established using finite element software.

[0028] By combining the above vehicle-rail coupling sub-model and ballastless track sub-model, a vehicle-track interaction model for train coupling is constructed.

[0029] Step S30: Based on the secondary development of general finite element software, construct a data interaction interface, use the data interaction interface to interact with the vehicle-rail interaction model in real time to calculate data, solve the above vehicle-rail interaction model, realize the simulation of the dynamic interaction of the system under the coupling effect of temperature and train, and calculate the spatial temperature field and temperature deformation of the track structure.

[0030] Step S40: By comparing with the field measurement data, the correctness and reliability of the model were verified.

[0031] Step S10 above includes: a thermo-mechanical coupling analysis model of ballastless track based on the finite element method provided in this embodiment of the invention, as follows: Figure 2As shown, the thermo-coupling analysis model of the ballastless track includes a continuous medium model comprising rails, fasteners, track slabs, self-compacting concrete, and a base plate. The rails directly bear the wheel-rail impact load, and periodically discrete Timoshenko beams are used to simulate vertical, lateral bending, torsion, and axial vibrations. Fasteners are simulated using triaxial spring-damped elements, and the fastener force is evenly distributed to the track slab through distributed coupling. The track slab, self-compacting concrete, and base plate are all simulated using solid elements. The track slab and self-compacting concrete are considered as a single unit through coupled nodal degrees of freedom, referred to as a composite plate. Surface-to-surface contact is established between the self-compacting concrete and the base plate, with the Penalty function used vertically and friction contact set tangentially.

[0032] The surface boundary conditions and interlayer contact conditions of the above-mentioned ballastless track thermo-coupling analysis model satisfy the basic principles of heat transfer and consider the thermal conductivity characteristics of the geotextile and elastic cushion layer. When performing thermo-coupling analysis on the ballastless track, the comprehensive atmospheric temperature and overall heat transfer coefficient of each structural surface were calculated using heat transfer analysis theory based on geographical and meteorological data. Furthermore, the model also needs to consider the influence of gravity on structural deformation, calculating the spatial temperature field and temperature deformation of the track structure. The calculation results of the above-mentioned ballastless track thermo-coupling analysis model serve as the initial boundary conditions for subsequent calculations of the ballastless track sub-model.

[0033] Step S20 above includes: 1) Vehicle-rail coupled sub-model The vehicle-rail coupled sub-model primarily considers the vibrations of various vehicle components and the rails. Chinese high-speed railway trains consist of multiple four-axle locomotive cars, each containing a car body, two bogies, and four wheelsets. Based on multibody dynamics theory, each component is considered for heave, lateral movement, roll, pitching, and yaw, totaling 35 degrees of freedom.

[0034] The rail is simulated using a discretely supported Timoshenko beam, and its dynamic equations are solved using the modal superposition method. The equations of motion for both the vehicle and the rail are: (1) (2) in (3) In the formula , and These are the mass, stiffness, and damping matrices, respectively, with subscripts v and r representing the vehicle and rail, respectively. , and These are displacement, velocity, and acceleration vectors, respectively. and These are the vehicle's weight vector and the wheel-rail force vector, respectively. , and These are the generalized mass, damping, and stiffness matrices of the rail, respectively. The front reserved for the rails n The first-order free mode matrix; The modal frequency of the rail; and These are the displacement vectors in the physical and modal spaces of the rail, respectively. It is the generalized load force vector of the fasteners borne by the rail.

[0035] Normal force in the wheel-rail force vector This is determined by Hertz's nonlinear elastic contact theory and can be expressed as:

[0036] Where G is the wheel-rail contact constant. The track is uneven. It is time t. j Vertical displacement of the wheel set It is time t. j Vertical displacement of the rail at the wheel set position.

[0037] The tangential creep force is calculated based on Kalker's linear creep theory. Since Kalker's linear creep theory is only applicable to cases with low creep rates, a nonlinear correction is needed for cases with high creep rates. The Shen-Hedrick-Elkins model is used to introduce correction coefficients, resulting in the corrected longitudinal, lateral, and rotational creep forces of the wheel and rail, which can be expressed as follows:

[0038] in The wheel-rail creep coefficient, , and These are the longitudinal, lateral, and spin creep rates of the wheel-rail system, respectively. This is a correction factor.

[0039] 2) Ballastless track bed sub-model

[0040] The ballastless track sub-model primarily considers the vibration of the track slab, self-compacting concrete, and base slab. A finite element model of the ballastless track sub-model was established using finite element software. For the dynamic analysis, the calculation results of the ballastless track thermo-mechanical coupling analysis model were used as the initial boundary conditions for subsequent calculations of the ballastless track sub-model. Its equations of motion are: (6) In the formula: the subscript 's' indicates the lower track structure. This represents the temperature-dependent stiffness matrix. This represents the initial displacement of the structure caused by thermal strain. This represents the equivalent load of thermal stress.

[0041] 3) Establishment of the coupling model

[0042] Based on the establishment of the above two sub-models, the present invention establishes a vehicle-track interaction model of temperature and train coupling using a combination of self-programming and general-purpose finite element software, as follows: Figure 3 As shown in the figure. The vehicle-rail coupling sub-model was implemented using self-programming, while the ballastless track bed sub-model considering complex temperature effects was implemented using finite element software.

[0043] The dynamic contact relationship between wheel and rail is the core of connecting the vehicle and the track system. First, the wheel-rail spatial contact geometry is calculated using the trace method. After obtaining the trace on the wheel tread and the rail head profile at a certain moment, the minimum distance method is used to solve for the wheel-rail contact points on the left and right sides. Then, based on the left and right wheel-rail contact points, the wheel-rail contact geometry parameters, including the curvature of the contact points on the wheel tread and rail profile, the position of the contact points in the wheelset and rail coordinate system, and the contact angle, can be obtained. Finally, the wheel-rail interaction force is solved using formulas (4)-(5) based on the above information.

[0044] The above step S30 includes, The solution process for the aforementioned vehicle-track interaction model includes: the vehicle-rail coupling sub-model is implemented using self-programming, while the ballastless track sub-model is built using general-purpose finite element software. A data interface for real-time information exchange between the two sub-models was developed based on the FORTRAN language, and the data includes inter-layer displacement and force information. Different solution algorithms can be used for the two sub-models: the vibration of the vehicle-rail coupling sub-model is solved using explicit dynamics, while the vibration of the ballastless track sub-model can be solved using implicit dynamics. This method can better consider the refined modeling and nonlinear factors of the ballastless track and achieve the solution of system vibration under temperature and train coupling effects. Furthermore, to improve computational efficiency, a multi-time-step solution method is adopted. The vehicle-rail coupling sub-model uses a small step size, while the ballastless track sub-model uses a large step size. The large and small time steps can be expressed as: (7) in and These are large time steps and small time steps, respectively. m times .

[0045] Within a single large time step, the main calculation steps are as follows: (1) The calculation result of the above large time step is used as the initial state of the current large time step. Assume that in the current large time step... The fastening force and large time step of the ballastless track bed model Equal to each other, solve equation (6) to obtain the dynamic response of the ballastless track bed sub-model.

[0046] (2) Calculate the fastening force on the vehicle-rail coupled sub-model at small time steps based on the dynamic response of the track slab, and obtain the fastening force on the vehicle-rail coupled sub-model at different times according to linear interpolation. By solving equations (1)-(2) step by step, the dynamic response of the vehicle-rail coupled sub-model within a small time step can be obtained.

[0047] (3) Solve for the fastening force based on the dynamic response of the rail and track slab at the end of the large time step. This fastening force is used as the initial fastening force for the next large time step, and the above steps are repeated to solve for the dynamic response of the coupled system.

[0048] The application process of the above vehicle-track interaction model is as follows: Figure 4 The process, as shown, includes the following steps: First, simulation parameters of the vehicle and track structure are read to establish a vehicle-rail coupled sub-model and a ballastless track sub-model. Then, based on the thermo-mechanical coupling analysis model of the ballastless track, the deformation and stress state of the track structure under the action of the temperature field are calculated. Track irregularities are updated based on the deformation of the rail. In each analysis step, the irregularity amplitude at each wheel-rail contact point is determined according to the position of the train on the track and the response results of the vehicle and track in the previous analysis step. Based on the wheel-rail contact geometry, the wheel-rail vertical force and creep force are calculated. A data interaction interface program for the two sub-models is developed to calculate the fastening force in each time step by interacting with the displacement and velocity of the rail and track slab. After obtaining the wheel-rail interaction force and the fastening force, the dynamic response of the vehicle and rail can be obtained by explicit integration algorithm, and the dynamic response of the ballastless track can be obtained by implicit integration method. The above process is continuously repeated until the vehicle runs out of the temperature effect zone.

[0049] The "ballastless track spatial temperature effect" described in this invention refers to the non-uniform temperature distribution in three-dimensional space (longitudinal, transverse, and vertical) of the ballastless track structure under the influence of natural ambient temperature, and its impact on the geometric deformation of the track structure. Specifically, it includes the following aspects: (1) Non-uniform temperature distribution characteristics: Considering the influence of factors such as solar radiation and ambient temperature, the ballastless track structure exhibits non-linear and non-uniform temperature distribution in the thickness direction (vertical) and along the track direction (longitudinal and transverse), with obvious gradient changes and phase differences.

[0050] (2) Structural warping caused by temperature difference: Temperature difference causes structural components such as track slabs to warp, forming irregular spatial deformation (geometric irregularity), which manifests as periodic vertical and horizontal undulations of the track structure.

[0051] What are the components of track structure stiffness irregularities caused by spatial temperature effects in ballastless tracks and nonlinearities in interlayer contact states during train operation?

[0052] (1) Temperature-induced structural stiffness degradation and non-uniformity: Temperature effect leads to changes in material modulus and changes in the contact state between structural layers, thereby causing a decrease in the overall stiffness of the track structure, and exhibiting periodic or local non-uniform stiffness characteristics in space.

[0053] (2) Evolution of interlayer contact state in track structure: Under temperature influence, the contact state between different layers of the track structure changes, leading to localized voids in the track structure. When a train passes, the interlayer contact area and contact gap exhibit nonlinear changes, thereby affecting the structural dynamic response under train load. Step S40 above includes: Figure 5 This invention provides a field test diagram of a vehicle-track dynamics model under temperature and temperature effects, using field test data from China's high-speed railways to verify the model. The test section of this line is laid with CTRS III type ballastless track, and the test train is a six-car CRH380AM high-speed train. The test was conducted during the high-temperature period of summer, with an average ambient temperature of 29.5℃. Accelerometers with a range of 10g were placed in and at the ends of the track slab.

[0054] Figure 6 This is a comparison chart of measured and simulated acceleration of a track slab at different times of day, provided as an embodiment of the present invention. From... Figure 6 It can be seen that the measured and simulated track slab angular accelerations are both greater than the mid-slab accelerations, and the response amplitudes and time history curves of the simulated and measured accelerations show good consistency. In the simulation model, the mid-slab acceleration at 14 hours is greater than that at 8 hours, while the angular acceleration at 8 hours is greater than that at 8 hours. Measured data show that the angular acceleration at 8:10 is greater than that at 14 hours and exhibits more pronounced fluctuations, following the same pattern as the simulation results.

[0055] In summary, compared to self-programmed models, the vehicle-track interaction model proposed in this invention reduces programming difficulty and development costs while achieving accurate simulation of the spatial temperature effects on ballastless tracks. Furthermore, this method can effectively simulate the track structure stiffness irregularities caused by temperature effects and the nonlinearity of interlayer contact states during train operation. The vehicle-track interaction model proposed in this invention accurately simulates the dynamic contact relationship between wheels and rails, more accurately predicts the vibration characteristics of structures such as rails, and achieves accurate simulation of the dynamic characteristics of the coupled system.

[0056] This invention employs finite element method (FEM) software to establish a thermo-mechanical coupling model of ballastless track, which can accurately simulate the spatial temperature effects of ballastless track. Furthermore, a vehicle-rail model is established using self-programming, and a data exchange interface between the two models is developed to transmit interlayer relative displacement and stress data, achieving a refined simulation of vehicle-track interaction under the coupled effects of temperature and train. This invention can provide scientific theoretical guidance for the design, maintenance, and repair of high-speed railway ballastless tracks. The vehicle-track interaction simulation model based on temperature and train coupling proposed in this invention has higher computational accuracy and more comprehensive computational functions.

[0057] Those skilled in the art will understand that the accompanying drawings are merely schematic diagrams of one embodiment, and the modules or processes shown in the drawings are not necessarily essential for implementing the present invention.

[0058] As can be seen from the above description of the embodiments, those skilled in the art can clearly understand that the present invention can be implemented by means of software plus necessary general-purpose hardware platforms. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in various embodiments or some parts of the embodiments of the present invention.

[0059] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, for apparatus or system embodiments, since they are basically similar to method embodiments, the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments. The apparatus and system embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0060] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A simulation method for vehicle-track interaction coupled with temperature and train, characterized in that, include: A thermo-mechanical coupling analysis model of ballastless track was established using the finite element method to calculate the spatial temperature field and temperature deformation of the track structure. A vehicle-rail coupling sub-model was built based on self-programming. Based on the aforementioned thermo-mechanical coupling analysis model of ballastless track, a sub-model of ballastless track bed considering complex temperature effects is established; The ballastless track sub-model interacts with the vehicle-rail coupling sub-model in real time through a data interaction interface to calculate data, including the dynamic characteristics of the vehicle-track system under temperature and train coupling. Based on the aforementioned thermo-mechanical coupling analysis model of ballastless track, a sub-model of the ballastless track bed considering complex temperature effects is established, including: Based on the aforementioned thermo-mechanical coupling analysis model of ballastless track, a sub-model of the ballastless track bed considering complex temperature effects is established using finite element software. This sub-model considers the vibration of the track slab, self-compacting concrete, and base slab. The thermo-mechanical coupling analysis results of the aforementioned model are used as the initial boundary conditions for the sub-model. The equations of motion for the sub-model are as follows: （6） In the formula , and These represent the mass, stiffness, and damping matrices of the ballastless track bed. , and These are the displacement, velocity, and acceleration vectors of the ballastless track bed, respectively. This represents the temperature-dependent stiffness matrix. This represents the initial displacement of the structure caused by thermal strain. Indicates the equivalent load of thermal stress. It is the load vector of the fasteners borne by the ballastless track bed.

2. The method according to claim 1, characterized in that, The aforementioned method of establishing a thermo-mechanical coupling analysis model for ballastless track using the finite element method to calculate the spatial temperature field and temperature deformation of the track structure includes: A thermo-mechanical coupling analysis model for ballastless track was established using the finite element method. This model includes a continuous medium model of rails, fasteners, track slabs, self-compacting concrete, and base plate. The rails directly bear the wheel-rail impact load and are simulated by periodically discrete Timoshenko beams to simulate vertical, lateral bending, torsion, and axial vibrations. The fasteners are simulated using triaxial spring-damping elements, and the fastener forces are evenly distributed to the track slab through distributed coupling. The track slab, self-compacting concrete, and base plate are all simulated using solid elements. The surface boundary conditions and interlayer contact conditions of the thermal coupling analysis model of the ballastless track satisfy the basic principles of heat transfer. Based on geographical and meteorological data, the comprehensive atmospheric temperature and overall heat transfer coefficient of each structural surface are calculated using heat transfer analysis theory, and the spatial temperature field and temperature deformation of the track structure are calculated.

3. The method according to claim 2, characterized in that, The aforementioned self-programmed vehicle-rail coupling sub-model includes: A vehicle-rail coupled sub-model was established based on self-programming. This sub-model considers the vibration of various vehicle components and the rail. The rail is simulated using a discretely supported Timoshenko beam. The dynamic equations of the rail are solved using the modal superposition method. The motion equations of the vehicle and the rail are as follows: （1） （2） in （3） In the formula , and These are the mass, stiffness, and damping matrices, respectively, with subscripts v and r representing the vehicle and rail, respectively. , and These are displacement, velocity, and acceleration vectors, respectively. and These are the vehicle's weight vector and the wheel-rail force vector, respectively. , and These are the generalized mass, damping, and stiffness matrices of the rail, respectively. The first n free mode matrices reserved for the rail; The modal frequency of the rail; and These are the displacement vectors in the physical and modal spaces of the rail, respectively. It is the generalized load force vector borne by the fasteners on the rail; Normal force in the wheel-rail force vector It is determined by Hertz's nonlinear elastic contact theory and is expressed as: （4） Where G is the wheel-rail contact constant. The track is uneven. It is the vertical displacement of the j-th wheelset at time t. It is the vertical displacement of the rail at the position of the j-th wheelset at time t; The tangential creep force was corrected by introducing a correction coefficient using the Shen-Hedrick-Elkins model, resulting in the corrected wheel-rail longitudinal creep force. Lateral creep force and rotational creep force Expressed as: （5） in The wheel-rail creep coefficient, , and These are the longitudinal, lateral, and spin creep rates of the wheel-rail system, respectively. For correction factor, , and These are the longitudinal creep force, lateral creep force, and rotational creep force of the wheel and rail before correction.

4. The method according to claim 3, characterized in that, The ballastless track sub-model interacts with the vehicle-rail coupling sub-model in real time via a data interaction interface to calculate the dynamic characteristics of the vehicle-track system under temperature and train coupling effects, including: The ballastless track sub-model uses a data interaction interface built through secondary development of finite element software. This sub-model interacts with the vehicle-rail coupling sub-model in real time to calculate data. The vibration of the vehicle-rail coupling sub-model is solved using explicit dynamics, while the vibration of the ballastless track sub-model is solved using implicit dynamics. The vehicle-rail coupling sub-model uses a small time step, while the ballastless track sub-model uses a large time step. The large and small time steps can be expressed as: （7） in and These are the large time step and the small time step at time i, respectively. For the (i-1)th time step, For the initial small time step, and These are large time steps and small time steps, respectively. m times ; Within a single large time step, the computation steps include: (1) The calculation result of the above large time step is used as the initial state of the current large time step. It is assumed that in the current large time step... The fastening force and large time step of the ballastless track bed model Equal to each other, solve equation (6) to obtain the dynamic response of the ballastless track bed sub-model; (2) Calculate the fastening force on the vehicle-rail coupled sub-model at small time steps based on the dynamic response of the track slab, and obtain the fastening force on the vehicle-rail coupled sub-model at different times by linear interpolation. By solving equations (1)-(2) step by step, the dynamic response of the vehicle-rail coupling sub-model within a small time step is obtained. (3) Solve for the fastener force based on the dynamic response of the rail and track slab at the end of the large time step. This fastener force is used as the initial fastener force for the next large time step. Repeat the above steps to solve for the dynamic response of the coupled system. The deformation and stress state of the track structure under the action of temperature field are calculated based on the thermo-mechanical coupling analysis model of ballastless track. The track irregularity is updated based on the deformation of the rail. In each analysis step, the irregularity amplitude of each wheel-rail contact point is determined according to the position of the train on the track and the response results of the vehicle and the track in the previous analysis step. Based on the wheel-rail contact geometry, the wheel-rail vertical force and creep force are calculated. The data is interactively calculated in real time with the vehicle-rail interaction model using a data interaction interface. The fastener force in each time step is calculated by interacting with the displacement and velocity of the rail and the track slab to obtain the wheel-rail interaction force and the fastener force. The dynamic response of the vehicle and the rail is obtained by explicit integration algorithm and the dynamic response of the ballastless track bed is obtained by implicit integration method. The above process is continuously repeated until the vehicle runs out of the temperature effect section.

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