Simulation calculation method and system for accurately calculating dynamic curve passing of train
By establishing a three-dimensional coupled dynamic model of train vehicle-track and a refined simulation calculation method, the problems of oversimplification of models and limitations in dynamic process simulation in existing technologies are solved. This enables efficient and accurate simulation calculation of train dynamic curve passage, reducing dependence on large commercial software.
Patent Information
- Application Number
- CN202511085381.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-04
- Publication Date
- 2025-11-21
AI Technical Summary
Existing simulation methods suffer from problems such as oversimplification of models, limitations in simulating dynamic processes and operating conditions, and strong reliance on engineer experience when trains pass through dynamic curves, resulting in inaccurate calculation results and low computational efficiency.
A three-dimensional coupled dynamic model based on the train vehicle-track system was adopted to establish the motion differential equations for each rigid body degree of freedom of the system. The main program and subroutines were developed using Visual FORTRAN, and combined with detailed wheel-rail contact and suspension force analysis, simulation calculations of the train's dynamic curve passage were performed.
It enables accurate simulation calculations of train dynamic curve passage, improves the accuracy of calculation results and the efficiency of engineering applications, reduces reliance on large commercial software, and lowers costs.
Smart Images
Figure CN120995924A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application belongs to the technical field of rail vehicle engineering, and particularly relates to a simulation calculation method and system for accurately calculating train dynamic curve passing. BACKGROUND
[0002] Train dynamic curve passing simulation is a key technology in rail vehicle engineering, which is used to evaluate the safety, stability and wheel-rail wear performance of the train passing through the curve. However, the existing simulation methods and technologies still have certain deficiencies, mainly in the following aspects:
[0003] 1. Over-simplified simulation model problem The wheel-rail contact geometric relationship is usually described by table lookup method or analytical formula (such as Hertz contact), ignoring the influence of actual profile (especially after wear) of wheel-rail, curve line parameter variation, wheelset yaw and other factors on the contact relationship, and the processing ability of multi-point contact and conformal contact is limited; the widely used linear or simplified nonlinear (such as Shen-Hedrick-Elkins, FASTSIM) creep theory has decreased precision under large creep rate (such as wheel flange sticking, large traction / braking force) or extreme working conditions; for the nonlinear suspension elements of vehicle suspension system (such as air spring, hydraulic shock absorber, car coupler connection gap, stop clearance, dry friction wedge, etc.), linear model or overly simplified nonlinear model is usually used in simulation, which is difficult to accurately capture the dynamic characteristics; the track is usually regarded as a rigid foundation or a simple mass-spring-damper system (discrete support), while the actual track (rail, sleeper, track bed, subgrade) is a complex elastic continuum, and its vibration characteristics will affect the transmission of wheel-rail force and the dynamic response of the vehicle; the idealized circular curve + transition curve model is usually used in simulation of track curve parameters, ignoring the superimposed influence of curvature, superelevation, side roll angle deviation on vehicle suspension and dynamic force in actual line.
[0004] 2. Dynamic process and working condition simulation limitation problem Generally, simulation starts from a certain "stable" state, but the actual train entering and leaving the curve is a dynamic process, and the vehicle pose, speed fluctuation and other factors before and after entering the curve have a direct impact on its curve passing behavior, and accurate simulation of the entire dynamic process of the curve requires more detailed settings; simulation of coupled complex operating conditions of long train passing through slope curve is less, which needs to consider the combination of traction / braking force, track irregularity, vehicle formation (especially the influence of car coupler force in long formation), line curvature and slope, and calculation of these working conditions is crucial for train safety evaluation; the existing simulation cannot efficiently and accurately predict the evolution of wear and its reaction on subsequent dynamic performance (which requires complex iteration or multi-scale simulation).
[0005] 3. The high-precision model (such as considering fine wheel-rail contact and complex nonlinearity) has a huge calculation amount, which limits its feasibility in multi-parameter optimization and real-time / quasi-real-time applications (such as digital twinning); the accuracy of the simulation model is highly dependent on input parameters (such as suspension parameters, wheel-rail friction coefficient, track stiffness and damping, material properties), but many parameters are difficult to accurately measure and obtain, resulting in a large error in the prediction of the simulation model; although large commercial simulation software (such as SIMPACK, UM, etc.) has powerful functions, it is mostly "black box", that is, users lack understanding of the basic algorithms, logic and specific assumptions of the software underlying, and need to highly rely on the personal experience and judgment of engineers in model building, parameter setting and result analysis, which can easily lead to distorted results or even calculation errors.
[0006] Through the above analysis, the problems and defects of the prior art are:
[0007] (1) The simulation model is oversimplified.
[0008] (2) The dynamic process and working condition simulation has limitations.
[0009] (3) In model building, parameter setting and result analysis, it is necessary to highly rely on the personal experience and judgment of engineers, which can easily lead to distorted results or even calculation errors. SUMMARY
[0010] In view of the problems existing in the prior art, the present application provides a simulation calculation method for accurately calculating the dynamic curve passing of a train.
[0011] The present application is implemented as follows: a simulation calculation method for accurately calculating the dynamic curve passing of a train comprises:
[0012] Step 1: based on the train vehicle-track three-dimensional coupled dynamics model and force analysis, the motion differential equations of each rigid body degree of freedom of the system are established;
[0013] Step 2: three-dimensional sequences are used to define the displacement, velocity and acceleration of each degree of freedom of the rigid body;
[0014] Step 3: according to the train vehicle structure form and parameters and the curve track basic structure, the train vehicle and track structure parameter files are formed, which are convenient for automatic reading during program running;
[0015] Step 4: the main program Main and each subprogram are programmed by using Visual FORTRAN, including the curve program, the wheel-rail contact program, the wheel-rail creep force and normal force program, the suspension force program, the acceleration program, the hook force program, the braking force program, the numerical calculation method program, the track structure program and the line spectrum excitation program;
[0016] Step 5: Input the curve parameters, operating conditions, and vehicle speed to perform train curve passage simulation calculations.
[0017] Furthermore, the motion differential equations for each rigid body degree of freedom of the system are established as follows:
[0018] 1) Regardless of how the rigid bodies of the vehicle system change, the relationship between the different rigid body coordinate systems (i.e., the center-of-mass coordinate system) at the suspension point can be considered as a certain coordinate system (O). B -X B Y B ZB) is another coordinate system (O) A -X A Y A Z A A new coordinate system is formed after translation (a, b, c) and rotation (α, θ, γ), where α is the coordinate system about the X-axis. A The rotation angle of the axis; θ is the angle around the Y axis. A The rotation angle of the axis; γ is the angle around Z. A The rotation angle of the axis; then the relationship between the two coordinate systems is:
[0019]
[0020] or
[0021]
[0022] In the formula:
[0023]
[0024] If we only need to know the displacement relationship and rotation relationship between the two coordinates, we can perform coordinate transformation according to the above formula (1) or (2);
[0025] 2) Suppose a moving point moves along the centerline of a curved track, then the relative position of the moving point... Figure 1 The relationship between the rotation angles (α, θ, γ) of the absolute coordinate system O-XYZ and the distance l traveled by the moving point on each curve segment can be derived as follows (where the transition curve is a cubic parabola of superelevation slope):
[0026] Roll angle α:
[0027]
[0028] Downhill angle θ:
[0029]
[0030] Central angle γ:
[0031]
[0032] In the formula: a0 is half the center distance between the inner and outer rails, l h1 Length of the initial transition curve; l y Length of circular curve; l h2 Length of the initial easing curve.
[0033] Another objective of this invention is to provide a simulation calculation system for accurately calculating the passage of train dynamic curves, comprising:
[0034] A module is established to create the motion differential equations for each rigid body degree of freedom of the system based on the three-dimensional coupled dynamics model of the train vehicle-track and the force analysis.
[0035] The definition module is used to define the displacement, velocity, and acceleration of each degree of freedom of a rigid body using a three-dimensional numerical sequence;
[0036] The parameter generation module is used to generate parameter files for train vehicles and track structures based on the structural form and parameters of the train vehicles and the basic structure of the curved track, so that the program can automatically read them during runtime.
[0037] The programming module is used to program the main program and various subroutines using Visual FORTRAN, including curve programs, wheel-rail contact programs, wheel-rail creep force and normal force programs, suspension force programs, acceleration programs, coupler force programs, braking force programs, numerical calculation method programs, track structure programs, and track spectrum excitation programs.
[0038] The simulation calculation module is used to input curve parameters, operating conditions, and vehicle speed to perform simulation calculations for train curve passage.
[0039] Another object of the present invention is to provide a computer device, the computer device including a memory and a processor, the memory storing a computer program, the computer program being executed by the processor causing the processor to perform the steps of the simulation calculation method for accurately calculating the passage of a train dynamic curve.
[0040] Another object of the present invention is to provide a computer-readable storage medium storing a computer program, which, when executed by a processor, causes the processor to perform the steps of the simulation calculation method for accurately calculating the passage of a train's dynamic curve.
[0041] Another objective of this invention is to provide an information data processing terminal, which is used to implement the simulation calculation system for accurately calculating the passing of train dynamic curves.
[0042] Based on the above technical solutions and the technical problems solved, the advantages and positive effects of the technical solution to be protected by this invention are as follows:
[0043] First, a refined three-dimensional coupled dynamic model of the interaction between heavy-haul trains and tracks is developed, fully considering the nonlinear aspects of locomotive and rolling stock suspension (such as axle box suspension nonlinearity, center plate contact nonlinearity, wedge friction nonlinearity, coupler gap impact and dry friction nonlinearity, and buffer nonlinear hysteresis impedance) and the continuous variation of multiple parameters on curved tracks. For example, the coupler is modeled as an independent rigid body component to analyze its actual coupling and vibration characteristics. Combined with gas flow theory, the air braking model is further improved, considering the influence of train formation on brake wave distribution and transmission, as well as the influence of braking force and brake shoe pressure distribution on the wheel-rail dynamics during braking. A three-layer continuous discrete-point spring-damping support model of the entire curved track length (rail-sleeper-ballast-subgrade) is adopted, fully considering the superimposed effects of curved track curvature, superelevation, gradient, and roll angle deviations on train and rolling stock suspension and dynamics.
[0044] This study optimizes existing Hertz contact theory, CONTACT wheel-rail contact algorithm, and Kalker linearly simplified creep theory. Based on finite element wheel-rail creep theory, the SRST wheel-rail contact method, and the self-excited vibration theory of wheel-rail rolling friction, it develops a method applicable to wheel-rail contact and wear research under complex coupled conditions such as slope curves. Furthermore, differences in posture and dynamic torsion exist between train vehicles or between different rigid body components of the same vehicle on curves. When calculating the relative displacement and relative velocity of each rigid body component, a coordinate transformation to the same coordinate system is required. This coordinate transformation presupposes accurate calculation of the relative superelevation difference, center angle difference, roll angle difference, and slope angle difference between the rigid bodies of the vehicle.
[0045] To address the "black box" problem in the underlying calculation algorithms of general large-scale commercial simulation software (such as SIMPACK, UM, etc.), the simulation calculation program of this invention is written in the open-source Visual FORTRAN. Users can modify the corresponding parameters or subroutines to meet the needs of different calculation conditions, and continuously optimize and improve the corresponding calculation methods based on the simulation calculation results.
[0046] Secondly, this technical solution and its supporting calculation program can comprehensively consider the operating conditions of curved tracks and freight trains based on specific simulation curve conditions. The modeling is more comprehensive and refined, better matching actual operating conditions, and the simulation calculation results are more accurate. This provides better technical guidance for the actual operation of freight trains, improving their safety and reliability. Furthermore, using this technical solution and its simulation program can reduce reliance on large-scale simulation software such as SIMPACK and UM, significantly reducing the purchase cost of commercial software and the expenses for upgrades and maintenance.
[0047] By employing refined modeling of vehicle dynamic curves, various operating conditions of vehicles and tracks can be comprehensively considered when passing through curves, realizing full-domain, full-process simulation calculation and analysis of train-track longitudinal, lateral, and vertical coupling.
[0048] The analysis of train vehicle dynamic curves involves numerous nonlinear elements and a large number of degrees of freedom, including vehicles, tracks, and wheel-rail relationships. The balance between the level of modeling detail and the efficiency of simulation computation has always been a challenge. This technical solution utilizes fast numerical integration iteration methods and multi-GPU parallel computing, leveraging the rapid development of modern computers, artificial intelligence, and large-scale data models to effectively address this technical difficulty. Attached Figure Description
[0049] Figure 1 This is a flowchart of the simulation calculation method for accurately calculating the dynamic curve of a train provided in this embodiment of the invention;
[0050] Figure 2 This is a block diagram of the simulation calculation system for accurately calculating the dynamic curve of a train, provided in an embodiment of the present invention.
[0051] Figure 3 This is a typical railway curve diagram provided in the embodiments of the present invention;
[0052] Figure 4 This is a schematic diagram of the train passing through a curve provided in an embodiment of the present invention;
[0053] Figure 5 This is a diagram showing the positional relationship of the same rigid body component of a vehicle (truck) on a curve, provided in an embodiment of the present invention.
[0054] Figure 6 This is the vehicle-track coupled dynamics model (freight truck) provided in this embodiment of the invention;
[0055] Figure 7 This is a simulation calculation flowchart provided in an embodiment of the present invention;
[0056] Figure 8 This is a diagram showing the rigid body deflection angle difference at the same vehicle suspension point, provided in an embodiment of the present invention.
[0057] Figure 9 This is a diagram of the wheel-rail interaction force of a vehicle provided in an embodiment of the present invention;
[0058] Figure 10 This is a comparison diagram of wheel-rail response provided in an embodiment of the present invention. Detailed Implementation
[0059] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.
[0060] In existing industry practices, vehicle-track coupling analysis typically relies on multiple heterogeneous software programs, and inconsistent parameter formats can easily lead to deviations in calculation results. This invention utilizes the object-oriented Visual FORTRAN framework to solidify vehicle mass parameters, suspension damping parameters, and track structure parameters into two types of binary descriptors (*.veh and *.trk), unifying the calling interface and byte order. Simultaneously, a Hash-Map indexing acceleration mechanism is introduced into the main program to achieve millisecond-level parameter location and dynamic loading, fundamentally solving the cross-platform data consistency problem.
[0061] The spatial geometry of curved sections is crucial for wheel-rail forces, but traditional Euler angle approximation methods inevitably introduce truncation errors in transition curve sections. This invention derives a nonlinear rotation matrix of the curve centerline with mileage based on the Frenet framework, treats the superelevation slope of the transition curve as a cubic spline function, and introduces symmetric orthogonalization at the matrix level. This integrated coordinate transformation not only satisfies continuous first and second derivative constraints but also ensures the numerical stability of the rigid body inertia tensor in real-time updates, improving the prediction accuracy for long-wave excitation scenarios of high-suspension vehicles.
[0062] Wheel-rail contact equations are a time-consuming bottleneck, especially under high axle load conditions, where the creep force-normal force iteration converges slowly. This invention combines Hertz disk contact with Kalker quasi-static theory, introducing an improved instantaneous radial basis function (RBF) response surface as a predictor. It switches between explicit and implicit coupling solution modes in real time by comparing the residual function; and utilizes the IntelMKL parallel vector acceleration library to achieve a three-fold speedup of the wheel-rail contact equations within a single time step, while maintaining the error on the order of one Newton.
[0063] Track-vehicle coupled vibration is extremely sensitive to the parameters of the track's elastic base. To avoid stiffness mismatch caused by linearization assumptions, this invention employs uniform mass beam elements to segmentally discretize the sleeper-ballast-slab composite layer, and solves it in the time domain with the vehicle multibody system through a fully implicit Newmark-β integrator. This method preserves the longitudinal flexibility of the track while avoiding numerical drift at external coupling interfaces, achieving energy conservation within a 60-second time-domain simulation under single-core computation conditions.
[0064] To address the multi-objective optimization needs arising from differences in curve speed limits, superelevation design, and train formation, this invention constructs an adaptive differential evolution algorithm module outside the simulation kernel. This module directly calls simulation result vectors via shared memory, eliminating the need for file-level intermediaries. The algorithm uses peak wheel-rail lateral force, derailment coefficient, and slack line threshold as constraints, and curve radius, superelevation, train mass distribution, and operating speed as decision variables. It converges to the Pareto front in just a hundred iterations, providing automated design support for speed-up track upgrades.
[0065] To achieve a closed-loop engineering process, this invention is embedded into the dispatch center's CADAS platform as a dynamic link library. It generates a digital twin curve passage model by combining real-time train operation monitoring data. Fifty seconds before the train enters the curve, the system completes a global simulation and outputs a safety margin recommendation. This cross-departmental integrated architecture is the first to connect a high-fidelity dynamics solver with the dispatch decision-making system, providing a real-time, implementable curve passage safety assessment method for heavy-haul and high-speed railways, demonstrating the originality of the technical approach and its potential for industrial application.
[0066] like Figure 1 As shown, the simulation calculation method for accurately calculating the passage of a train's dynamic curve provided by an embodiment of the present invention includes the following steps:
[0067] S101, based on the three-dimensional coupled dynamic model of train vehicle-track and force analysis, establish the motion differential equations for each rigid body degree of freedom of the system;
[0068] S102 uses a three-dimensional numerical sequence to define the displacement, velocity, and acceleration of each degree of freedom of a rigid body;
[0069] S103, based on the train vehicle structure and parameters and the basic structure of the curved track, generates a parameter file for the train vehicle and track structure, which is convenient for the program to read automatically during runtime;
[0070] S104 uses Visual FORTRAN to develop the main program Main and various subroutines, including curve program, wheel-rail contact program, wheel-rail creep force and normal force program, suspension force program, acceleration program, hook-to-hook force program, braking force program, numerical calculation method program, track structure program, and track spectrum excitation program.
[0071] S105 allows you to input curve parameters, operating conditions, and vehicle speed to perform train curve passage simulation calculations.
[0072] The embodiment of this invention provides the motion differential equations for each rigid body degree of freedom of the system:
[0073] 1) Regardless of how the rigid bodies of the vehicle system change, the relationship between the different rigid body coordinate systems (i.e., the center-of-mass coordinate system) at the suspension point can be considered as a certain coordinate system (O). B -XB Y B ZB) is another coordinate system (O) A -X A Y A Z A A new coordinate system is formed after translation (a, b, c) and rotation (α, θ, γ), where α is the coordinate system about the X-axis. A The rotation angle of the axis; θ is the angle around the Y axis. A The rotation angle of the axis; γ is the angle around Z. A The rotation angle of the axis; then the relationship between the two coordinate systems is:
[0074]
[0075] or
[0076]
[0077] In the formula:
[0078]
[0079] If we only need to know the displacement relationship and rotation relationship between the two coordinates, we can perform coordinate transformation according to the above formula (1) or (2);
[0080] 2) Suppose a moving point moves along the centerline of a curved track, then the relative position of the moving point... Figure 1 The relationship between the rotation angles (α, θ, γ) of the absolute coordinate system O-XYZ and the distance l traveled by the moving point on each curve segment can be derived as follows (where the transition curve is a cubic parabola of superelevation slope):
[0081] Roll angle α:
[0082]
[0083] Downhill angle θ:
[0084]
[0085] Central angle γ:
[0086]
[0087] In the formula: a0 is half the center distance between the inner and outer rails, l h1 Length of the initial transition curve; l y Length of circular curve; l h2 Length of the initial easing curve.
[0088] like Figure 2 As shown, an embodiment of the present invention provides a simulation calculation system for accurately calculating the passage of a train's dynamic curve, comprising:
[0089] A module is established to create the motion differential equations for each rigid body degree of freedom of the system based on the three-dimensional coupled dynamics model of the train vehicle-track and the force analysis.
[0090] The definition module is used to define the displacement, velocity, and acceleration of each degree of freedom of a rigid body using a three-dimensional numerical sequence;
[0091] The parameter generation module is used to generate parameter files for train vehicles and track structures based on the structural form and parameters of the train vehicles and the basic structure of the curved track, so that the program can automatically read them during runtime.
[0092] The programming module is used to program the main program and various subroutines using Visual FORTRAN, including curve programs, wheel-rail contact programs, wheel-rail creep force and normal force programs, suspension force programs, acceleration programs, coupler force programs, braking force programs, numerical calculation method programs, track structure programs, and track spectrum excitation programs.
[0093] The simulation calculation module is used to input curve parameters, operating conditions, and vehicle speed to perform simulation calculations for train curve passage.
[0094] Another object of the present invention is to provide a computer device, the computer device including a memory and a processor, the memory storing a computer program, the computer program being executed by the processor causing the processor to perform the steps of the simulation calculation method for accurately calculating the passage of a train dynamic curve.
[0095] Another object of the present invention is to provide a computer-readable storage medium storing a computer program, which, when executed by a processor, causes the processor to perform the steps of the simulation calculation method for accurately calculating the passage of a train's dynamic curve.
[0096] Another objective of this invention is to provide an information data processing terminal, which is used to implement the simulation calculation system for accurately calculating the passing of train dynamic curves.
[0097] Specific implementation of the present invention:
[0098] The technical solution of this invention is as follows:
[0099] 1. Typical curved tracks of general railways, such as Figure 3As shown, the track consists of a circular curve connecting the preceding and following transition curves. From the straight line through the preceding transition curve to the circular curve, the track curvature k and superelevation h increase from 0 to 1 / R0 (R0 is the radius of the circular curve) and h0, respectively; at the circular curve, the superelevation and curvature remain unchanged; from the circular curve through the following transition curve to the straight line, the curvature k and superelevation h decrease from 1 / R0 and h0, respectively, to 0. The coordinate systems in the figure are defined as follows: O-XYZ absolute coordinate system, fixed at the center of the track on the horizontal plane. The X-axis is horizontally forward along the direction of travel, the Y-axis is horizontally inward, and the Z-axis is vertically downward; O1-X1Y1Z1 particle motion coordinate system, fixed on the center of mass of the rigid body moving on the track surface, with rotation angles relative to the absolute coordinate system's X, Y, and Z axes defined as (α, θ, γ), respectively.
[0100] 2. A schematic diagram of the train passing through the curve is shown below. Figure 4 As shown. Due to changes in parameters such as the curvature of the curve and the superelevation of the outer rail, each vehicle in the train is in a different position on the curve, and there is dynamic interaction between adjacent vehicles. Therefore, the coupler needs to be analyzed as an independent rigid body component to determine its dynamic changes and forces.
[0101] 3. A schematic diagram showing the positional relationship of different rigid body components of the same vehicle as they pass through a curve, as shown below. Figure 5 As shown in the figure (the illustration shows a typical freight car structure). Due to the difference in superelevation, roll angle, and curvature of the inner and outer rails, the positions of different rigid body components of the same vehicle also differ. The coordinates of the mass points of different rigid bodies at the suspension points are not parallel due to the twisting of the track. It is necessary to transform the different coordinate systems to the same coordinate system before the corresponding calculations can be performed.
[0102] 4. Regardless of how the rigid bodies of the vehicle system change, the relationship between the different rigid body coordinate systems (i.e., the center-of-mass coordinate system) at the suspension points can be considered as a certain coordinate system (O). B -X B Y B ZB) is another coordinate system (O) A -X A Y A Z A A new coordinate system is formed after translation (a, b, c) and rotation (α, θ, γ), where α is the coordinate system about the X-axis. A The rotation angle of the axis; θ is the angle around the Y axis. A The rotation angle of the axis; γ is the angle around Z. A The rotation angle of the axis. Then the relationship between the two coordinate systems is:
[0103]
[0104] or
[0105]
[0106] In the formula:
[0107]
[0108] If we only need to know the displacement relationship and rotation relationship between the two coordinates, we can perform coordinate transformation according to the above formula (1) or (2).
[0109] 5. Suppose a moving point moves along the centerline of a curved track, then the relative position of the moving point... Figure 3 The relationship between the rotation angles (α, θ, γ) of the absolute coordinate system O-XYZ and the distance l traveled by the moving point on each curve segment can be derived as follows (where the transition curve is a cubic parabola of superelevation slope):
[0110] Roll angle α:
[0111]
[0112] Downhill angle θ:
[0113]
[0114] Central angle γ:
[0115]
[0116] In the formula: a0 is half the center distance between the inner and outer rails, l h1 Length of the initial transition curve; l y Length of circular curve; l h2 Length of the initial easing curve.
[0117] 6. Based on the positional relationship between each vehicle of the train and between each rigid body component within the same vehicle on a straight line, the translation coordinates (a, b, c) between them can be determined. Then, based on the theoretical position of the vehicle and the rigid body component after entering the curve, the rotation angle of the center of mass of different vehicles or rigid bodies can be determined according to the above formulas (3) to (5). Then, the relative rotation angle difference of the rigid body at the suspension point can be calculated. Then, according to the above formulas (1) or (2), the coordinate transformation is performed to the same coordinate system, and the relative displacement and relative velocity of the suspension point can be obtained.
[0118] Based on the above relationships, a train curve passage subroutine (Curve) can be compiled using Visual FORTRAN. Combined with the main program (Main), wheel-rail contact program (WR-CONTACT), wheel-rail creep subroutine (Creep), wheel-rail normal force subroutine (N-Force), vehicle suspension force subroutine (Suspend), acceleration subroutine (Acceleration), coupler force calculation subroutine (Coupler), braking force calculation subroutine (Brake), numerical calculation method subroutine (Method), track structure subroutine (Track), and track spectrum excitation subroutine (Spectrum), dynamic train curve passage calculations can be performed.
[0119] Detailed implementation of the technical solution:
[0120] 1. Based on the three-dimensional coupled dynamic model of train vehicle-track ( Figure 6 ) and force analysis, and establish the motion differential equations for each rigid body degree of freedom of the system;
[0121] 2. Use a three-dimensional sequence to define the displacement, velocity and acceleration of each degree of freedom of a rigid body. For example, X-Wheel(200, 4, 3) defines the longitudinal degree of freedom of a wheelset, where 200 represents a train with a total of 200 cars, 4 represents the 4 wheelsets of a car (i = 1 to 4), and 3 represents the displacement, velocity and acceleration of that degree of freedom (j = 1 to 3).
[0122] 3. Based on the structural form and parameters of the train vehicles and the basic structure of the curved track, generate parameter files for the train vehicles (such as locomotives, freight cars, and passenger cars) and the track structure, so that the program can automatically read them during runtime;
[0123] 4. Use Visual FORTRAN to develop the main program and various subroutines, including curve program, wheel-rail contact program, wheel-rail creep force and normal force program, suspension force program, acceleration program, coupler force program, braking force program, numerical calculation method program, track structure program, and track spectrum excitation program;
[0124] 5. Input the curve parameters, operating conditions, and vehicle speed to perform train curve passage simulation calculations. See the flowchart for the entire simulation calculation process. Figure 7 ;
[0125] See simulation results. Figure 8 , Figure 9 .
[0126] The specific application field of this invention is the field of railway vehicle dynamics simulation calculation and analysis, mainly the simulation of train vehicle dynamic curve passing. The related products are the calculation method for accurately calculating the train dynamic curve passing and its supporting simulation calculation program.
[0127] like Figure 10 As shown, simulation calculations reveal that, considering only the head-up angle difference Δγ, considering the head-up angle difference Δγ + roll angle difference Δα, and considering all three factors (head-up angle difference Δγ + roll angle difference Δα + head-up angle difference Δθ), the maximum wheel-rail lateral forces are 15.31, 16.47, and 16.95 kN, respectively; the vertical forces are 138.5, 140.3, and 155.5 kN, respectively; the axial forces are 12.02, 13.71, and 14.28 kN, respectively; and the wheel-rail wear energy is 25.99, 30.31, and 33.18 N·m·m, respectively. -1The maximum simulation results differed by 10.71%, 12.27%, 18.80%, and 27.66%, respectively, indicating that ignoring the angle deviation of a certain curve would result in some deviation and cause the simulation results to be distorted to a certain extent.
[0128] It should be noted that embodiments of the present invention can be implemented in hardware, software, or a combination of both. The hardware portion can be implemented using dedicated logic; the software portion can be stored in memory and executed by a suitable instruction execution system, such as a microprocessor or dedicated-design hardware. Those skilled in the art will understand that the above-described devices and methods can be implemented using computer-executable instructions and / or included in processor control code, for example, such code provided on a carrier medium such as a disk, CD, or DVD-ROM, a programmable memory such as read-only memory (firmware), or a data carrier such as an optical or electronic signal carrier. The devices and modules of the present invention can be implemented by hardware circuitry such as very large-scale integrated circuits or gate arrays, semiconductors such as logic chips, transistors, or programmable hardware devices such as field-programmable gate arrays, programmable logic devices, etc., or by software executed by various types of processors, or by a combination of the above-described hardware circuitry and software, such as firmware.
[0129] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions, and improvements made by those skilled in the art within the scope of the technology disclosed in the present invention, and within the spirit and principles of the present invention, should be covered within the scope of protection of the present invention.
Claims
1. A method for calculating train dynamic curves through simulation, characterized in that, The method includes the following steps: A three-dimensional coupled dynamic model of the train vehicle and track was established, and the differential equations of motion for each rigid body degree of freedom of the system were derived. The displacement, velocity, and acceleration of each rigid body degree of freedom are described using a three-dimensional numerical sequence. Generate train vehicle parameter files and track structure parameter files based on train vehicle structural parameters and curved track foundation structure; The main program, Main, and subroutines for curve, wheel-rail contact, wheel-rail creep and normal forces, suspension force, acceleration, coupler force, braking force, numerical calculation, track structure, and track spectrum excitation were developed using Visual FORTRAN. The simulation calculation is completed by inputting curve parameters, operating conditions, and vehicle speed.
2. The method according to claim 1, wherein the translational displacements a, b, c between the rigid bodies and the rotational angles alpha, theta, gamma are coupled through a universal coordinate transformation matrix, the matrix elements of which are composed of trigonometric functions.
3. According to the method of claim 1, a closed expression is established between the transition curve, the circular curve, the path model of the transition curve and the moving point mileage l, so that the turning angles alpha, theta, and gamma correspond one-to-one with the mileage, and the center distance s of the inner and outer rails and the lengths of the transition curves l_h1 and l_h2 and the length of the circular curve l_y are stored in the track structure parameter file.
4. A train dynamic curve simulation calculation system, characterized in that, include: Equation establishment unit, three-dimensional sequence definition unit, parameter file generation unit, calculation program compilation unit, simulation calculation unit; The units are connected in sequence to form a data stream.
5. The system according to claim 4, wherein the equation-establishing unit includes a rigid body dynamics solver based on a vector matrix format and shares a memory interface with the three-dimensional sequence definition unit.
6. The system according to claim 4, wherein the parameter file generation unit includes a train vehicle parameter storage area and a curve track parameter storage area, and provides an interface for reading by path index.
7. The system according to claim 4, wherein the track structure subroutine pre-set by the calculation program compilation unit is discretized using finite segment beam elements and solved in the time domain using the Newmark integration method.
8. A computer program product having embedded instructions that, when executed by a processor, cause the processor to perform the method described in any one of claims 1 to 3.
9. A computer-readable storage medium storing the computer program product of claim 8.
10. A train curve safety assessment device, characterized in that, It includes a processor, a memory, and a graphical input-output interface, wherein the memory loads the system according to any one of claims 4 to 7, and the processor runs the system and outputs indicator curves.