Railway vehicle dynamic gauge calculation method based on fluid-structure coupling and rigid-flexible coupling

Abstract

The application discloses a kind of track vehicle dynamic limit calculation method based on fluid-solid coupling and rigid-flexible coupling, comprising: constructing the three-dimensional geometric model of track vehicle and flow field calculation domain, setting flow field boundary condition;Apply time-varying wind load condition, solve the aerodynamic force and aerodynamic moment suffered by vehicle by the transient solver of finite volume method;Establish vehicle rigid-flexible coupling multibody dynamics model, set observation point and record initial coordinate value;Aerodynamic force and aerodynamic moment are input into multibody dynamics model to calculate the dynamic displacement of observation point, obtain the maximum value of dynamic displacement;Calculate the static displacement of each observation point;Initial coordinate value, dynamic displacement maximum value and static displacement are superimposed, and dynamic envelope limit coordinate is obtained, to generate dynamic envelope limit;The application improves the physical reality and engineering applicability of dynamic envelope limit calculation, and provides technical support for the safe operation of track vehicle, railway limit standard formulation and safety evaluation of existing infrastructure.

Description

Technical Field

[0001] This invention relates to the field of clearance technology for rail vehicles, and in particular to a method for calculating dynamic clearance of rail vehicles based on fluid-structure interaction and rigid-flexible coupling. Background Technology

[0002] With the rapid development of high-speed rail and urban rail transit technologies, the continuous increase in train operating speeds, and the increasing complexity of the operating environment, vehicle operation safety and infrastructure space utilization efficiency have become core concerns of the industry. The vehicle dynamic envelope, as the definition of the maximum space a vehicle may occupy during operation, is a key basis for formulating railway clearance standards, verifying infrastructure clearances, conducting safety assessments, and preventing collisions between vehicles and facilities along the line or passing vehicles.

[0003] Currently, the mainstream methods for calculating the dynamic envelope of vehicles both domestically and internationally mainly follow traditional standards and specifications, such as GB 146.1-2020 Locomotive and Rolling Stock Clearance and EN 15273-3:2013 European railway clearance standards applicable to my country's mainline railways, and CJJ / T 96-2018 Metro Clearance Standard applicable to my country's urban rail transit. These standards specify the calculation parameters and safety margins under different operating conditions, providing important technical support for the industry.

[0004] At the implementation level, multibody system dynamics simulation technology has become an important engineering analysis tool. This method, by establishing multi-rigid-body dynamic models of various vehicle components and considering factors such as suspension characteristics and wheel-rail interaction, simulates the mechanical motion response of the vehicle under track excitation, effectively supporting the application of the aforementioned standards.

[0005] However, as train speeds approach 300 km / h and above, and as trains face complex operating environments such as strong crosswinds and tunnel intersections, existing calculation methods exhibit significant technical limitations: First, aerodynamic loads are oversimplified, neglecting unsteady effects. Existing methods typically simplify complex aerodynamic loads to static loads or approximations based on empirical formulas, failing to accurately reflect the unsteady aerodynamic forces and moments experienced by trains in time-varying wind fields such as sudden wind changes, gusts, tunnel pressure waves, and passing interference. This simplification fails to adequately consider the dynamic characteristics of aerodynamic loads and their potential fluid-structure interaction effects with the vehicle's structural response, leading to a risk of insufficient accuracy in predicting the dynamic envelope under extreme wind conditions.

[0006] Secondly, the car body is treated as a rigid body, neglecting its elastic deformation. Traditional methods generally treat the car body as a rigid body, considering only its rigid displacement. However, modern rail vehicles, in pursuit of lightweight design, commonly employ large, thin-walled structures, which undergo significant elastic deformation (including bending and torsional deformation) under the combined effects of aerodynamic loads and track excitation. Ignoring this flexibility effect will distort the calculation results of the dynamic envelope in critical areas such as the middle of the car body, potentially introducing safety risks and reducing the space utilization efficiency of infrastructure due to overly conservative design.

[0007] Third, the multiphysics coupling is not adequately considered. Existing methods typically employ an oversimplified linear superposition principle to handle the influence of different factors. In reality, there is a complex nonlinear coupling relationship between the random excitation of the track, the centrifugal force generated by the curve passage, and the dynamic wind load. This simplified approach makes it difficult to accurately simulate the comprehensive dynamic response of the vehicle under the combined effects of multiphysics coupling.

[0008] In summary, these technical limitations of existing methods make it difficult to accurately predict vehicle dynamic envelope under high-speed and complex operating conditions, which is insufficient for the precise design of vehicle safety operation assessments and railway clearance standards, thus constituting a key bottleneck restricting the development of rail vehicle technology. Summary of the Invention

[0009] This invention provides a dynamic clearance calculation method for rail vehicles based on fluid-structure interaction and rigid-flexible coupling, which overcomes the technical problems of low accuracy and poor reliability in dynamic envelope calculation caused by excessive simplification of aerodynamic loads, neglect of elastic deformation of the car body, and insufficient consideration of multi-physics coupling in traditional methods.

[0010] To achieve the above objectives, the technical solution of the present invention is as follows: A method for calculating the dynamic clearance of rail vehicles based on fluid-structure interaction and rigid-flexible coupling includes: S1: Construct a three-dimensional geometric model and flow field computational domain for the rail vehicle, and set the flow field boundary conditions of the flow field computational domain based on the three-dimensional geometric model; S2: Apply time-varying wind load to the rail vehicle under the flow field boundary conditions. Introduce the transient solver of the finite volume method, the turbulence model and the pressure-velocity coupling algorithm in the flow field calculation domain to solve the aerodynamic forces and aerodynamic torques of the vehicle under the time-varying wind load. S3: Establish a rigid-flexible coupled multibody dynamics model of the vehicle based on the vehicle structure and performance parameters, set the observation points in the rigid-flexible coupled multibody dynamics model of the vehicle, and record the initial coordinate values ​​of each observation point; S4: Input the aerodynamic force and aerodynamic torque into the rigid-flexible coupled multibody dynamics model of the vehicle, perform dynamic simulation of the rigid-flexible coupled multibody dynamics model of the vehicle under multiple working conditions, calculate the dynamic displacement of each observation point under each working condition, and then obtain the maximum value of the dynamic displacement of each observation point. S5: Calculate the static displacement of each observation point based on vehicle manufacturing and installation tolerances, wear and suspension parameter characteristics; S6: The initial coordinates, maximum dynamic displacement, and static displacement of each observation point are superimposed to obtain the dynamic envelope boundary coordinates of each observation point. The dynamic envelope boundary coordinates of each observation point are then connected to generate the dynamic envelope boundary of the entire rail vehicle.

[0011] Furthermore, based on the three-dimensional geometric model, the flow field boundary conditions of the computational domain are set, including: The front direction of the rail vehicle is set as the front of the flow field calculation domain, the side of the flow direction in the flow field calculation domain is set as the velocity inlet, the side opposite and adjacent to the velocity inlet is set as the pressure outlet, and the top and bottom surfaces are set as symmetrical boundaries.

[0012] Furthermore, time-varying wind load conditions are applied to the rail vehicle at the velocity inlet using a custom wind field function.

[0013] Furthermore, a rigid-flexible coupled multibody dynamics model of the vehicle is established based on the vehicle's structure and performance parameters, including: Based on the structural performance parameters of the rail vehicle, a multi-rigid-body dynamics model is built, and finite element models of the car body, frame, and wheelsets are constructed. The finite element models of the car body, frame, and wheelsets are elasticized to form elastic body models of the frame and wheelsets. The elastic body models are then imported into the multi-rigid-body dynamics model to form a rigid-flexible coupled multi-body dynamics model of the vehicle.

[0014] Furthermore, the observation points in the rigid-flexible coupled multibody dynamics model of the vehicle are set, including: Select characteristic sections along the longitudinal direction of the car body: the end of the first bogie, the center of the first bogie, the middle of the car body, the center of the second bogie, and the end of the second bogie. On each of the aforementioned characteristic sections, n observation points are set up to cover the entire outline of the vehicle body.

[0015] Furthermore, Simpack was used to perform dynamic simulations of the vehicle's rigid-flexible coupled multibody dynamics model under multiple working conditions in order to calculate the dynamic displacement of each observation point under each working condition.

[0016] Furthermore, the time-varying wind load conditions include modified "Chinese hat" type sudden wind, sinusoidal gust wind, and gradual gust wind; The modified custom wind field function for the "China hat" type sudden wind condition is shown in formula (1). (1) in, Indicates the duration of the wind condition; The custom function for the wind field of sinusoidal gusts is shown in formula (2). (2) The custom function for the wind field of the gradual gust is shown in formula (3). (3).

[0017] Beneficial effects: This invention provides a dynamic clearance calculation method for rail vehicles based on fluid-structure interaction and rigid-flexible coupling. It obtains high-precision unsteady aerodynamic loads under time-varying wind fields through fluid-structure interaction analysis and accurately simulates the elastic deformation of key components such as the car body using a rigid-flexible coupled multibody dynamics model, achieving deep coupling simulation of aerodynamic, structural, and kinematic multiphysics fields. This method significantly improves the physical realism and engineering applicability of dynamic envelope clearance calculations, resulting in more scientific and reliable calculation results. It provides strong technical support for the safe operation of rail vehicles, the formulation of railway clearance standards, and the safety assessment of existing infrastructure. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 The flowchart of the method for calculating the dynamic clearance of rail vehicles based on fluid-structure interaction and rigid-flexible coupling provided by the present invention is shown below. Figure 2 This is a schematic diagram of the flow field computational domain; Figure 3 A schematic diagram showing the mesh division of the flow field on and around the surface of a rail vehicle; Figure 4 Topological structure diagram of rigid-flexible coupled dynamics model of rail vehicle; Figure 5 A schematic diagram of the finite element model of a rail vehicle body; Figure 6 A schematic diagram of the finite element model of a rail vehicle bogie frame; Figure 7 A schematic diagram of a finite element model of a bogie wheelset for a rail vehicle. Figure 8 This is a schematic diagram showing the positions of five feature sections selected along the longitudinal direction of the vehicle body; Figure 9A schematic diagram showing the combined cross-sectional profile of the rail vehicle and the selection of observation points. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] This embodiment provides a method for calculating the dynamic clearance of rail vehicles based on fluid-structure interaction and rigid-flexible coupling, such as... Figure 1 As shown, it includes: S1: Construct a three-dimensional geometric model and flow field computational domain for the rail vehicle, and set the flow field boundary conditions of the flow field computational domain based on the three-dimensional geometric model; S2: Apply time-varying wind load to the rail vehicle under the flow field boundary conditions. Introduce the transient solver of the finite volume method, the turbulence model and the pressure-velocity coupling algorithm in the flow field calculation domain to solve the aerodynamic forces and aerodynamic torques of the vehicle under the time-varying wind load. S3: Establish a rigid-flexible coupled multibody dynamics model of the vehicle based on the vehicle structure and performance parameters, set the observation points in the rigid-flexible coupled multibody dynamics model of the vehicle, and record the initial coordinate values ​​of each observation point; S4: Input the aerodynamic force and aerodynamic torque into the rigid-flexible coupled multibody dynamics model of the vehicle, perform dynamic simulation of the rigid-flexible coupled multibody dynamics model of the vehicle under multiple working conditions, calculate the dynamic displacement of each observation point under each working condition, and then obtain the maximum value of the dynamic displacement of each observation point. S5: Calculate the static displacement of each observation point based on vehicle manufacturing and installation tolerances, wear and suspension parameter characteristics; S6: The initial coordinates, maximum dynamic displacement, and static displacement of each observation point are superimposed to obtain the dynamic envelope boundary coordinates of each observation point. The dynamic envelope boundary coordinates of each observation point are then connected to generate the dynamic envelope boundary of the entire rail vehicle.

[0022] Specifically, a fluid-structure interaction model of the vehicle is first established. Through fluid-structure interaction analysis, the aerodynamic forces and aerodynamic moments acting on the vehicle body under the action of wind are calculated. Fluid-structure interaction analysis combines the flow field of the rail vehicle with the three-dimensional geometric model for analysis. Secondly, a rigid-flexible coupled multibody dynamics model of the vehicle is established: a locomotive and rolling stock is a multibody system with vibration characteristics, which is composed of multiple components such as car body, frame, wheelset and so on, connected by elastic suspension elements. Based on the vehicle structure and performance parameters, a rigid-flexible coupled multibody dynamics model of the vehicle is established, observation points in the rigid-flexible coupled multibody dynamics model of the vehicle are set, and the initial coordinate values ​​of each observation point are recorded. Finally, the aerodynamic force and aerodynamic moment data are input into the rigid-flexible coupled multibody dynamics model of the vehicle to calculate the dynamic displacement data of each cross-section observation point and extract the maximum dynamic displacement value. The original coordinate values, static displacement and dynamic displacement maximum value of the observation point are superimposed to obtain the dynamic envelope boundary, that is, the complete dynamic envelope of the vehicle is drawn.

[0023] In a specific embodiment, the scheme for constructing a three-dimensional geometric model and a flow field computational domain for the rail vehicle, and setting the flow field boundary conditions of the flow field computational domain based on the three-dimensional geometric model, is as follows: Step 1: Create a 3D geometric model of the rail vehicle using SolidWorks, and simplify details such as pantographs and door handles that have little impact on the overall aerodynamic characteristics. Step 2: Construct a sufficiently large cuboid computational domain ("virtual wind tunnel") outside the 3D geometric model using ANSYS software, such as... Figure 2 As shown, the train model is wrapped to eliminate the interference of boundary effects on the flow field results; Specifically, in this embodiment, the length, width, and height of the computational domain are not less than 10 times the length of the vehicle body, 5 times the width of the vehicle body, and 5 times the height of the vehicle body, respectively. Step 3: Grid the computational domain, such as... Figure 3 As shown, a boundary layer mesh is generated on the train surface. Mesh refinement is applied in areas with drastic flow field changes (such as the front, rear, and bogie regions), while a sparser mesh is used in areas far from the train body to save computational resources. In this embodiment, the number of mesh cells in the refined region around the train body is approximately 3 million, and the total number of mesh cells in the entire computational domain is approximately 8 million. Step 4: Set the boundary conditions of the computational domain: Set the front of the rail vehicle as the front of the flow field computational domain, set the side of the flow field computational domain in the direction of the incoming flow as the velocity inlet, set the side opposite and adjacent to the velocity inlet as the pressure outlet, and set the top and bottom surfaces as symmetrical boundaries. Specifically, in this scheme, the front direction of the rail vehicle is set as the front of the flow field calculation domain, the left side is set as the velocity inlet, the right side, the front and back sides are set as pressure outlets, the pressure is set to 0 Pa, and the top and bottom surfaces are set as symmetrical boundaries.

[0024] In this solution, the methods for constructing the three-dimensional model of the vehicle body and setting boundary conditions are conventional techniques for those skilled in the art, and therefore will not be described in detail.

[0025] In a specific embodiment, under the flow field boundary conditions, a time-varying wind load is applied to the rail vehicle. A transient solver using the finite volume method, a turbulence model, and a pressure-velocity coupled algorithm are introduced into the flow field computational domain to solve for the aerodynamic forces and moments experienced by the vehicle under the time-varying wind load condition. Step 1: Apply time-varying wind load conditions to the rail vehicle at the velocity inlet boundary using a custom function via ANSYS. The time-varying wind load conditions include modified "Chinese hat" type sudden wind, sinusoidal gust wind, and gradual gust wind. The crosswind speed is 13.8 m / s, and the direction is along the negative Z-axis. The "Chinese hat" type sudden wind field adopts the modified sudden wind model, the sinusoidal gust wind field adopts the gradual transition gust wind field, and the gradual gust wind field, which is an unsteady wind field, uses UDF to apply the wind load. The modified custom wind field function for the "China hat" type sudden wind condition is shown in formula (4). (4) Where t represents the duration of the wind condition; The custom function for the wind field of sinusoidal gusts is shown in formula (5). (5) The custom function for the gradually changing gust wind field is shown in formula (6). (6) The custom wind field function is input into the velocity inlet via code to apply the load wind; In ANSYS, set the turbulence model to... The model uses the SIMPLE algorithm for pressure-velocity coupling and a transient solver based on the finite volume method for solving the problem. The calculation process employs a second-order discretization scheme, and the convergence residual accuracy is set to be on the order of 10 for the normalized flow field residuals. -4 The residual values ​​of the turbulence model are on the order of 10. -3 Each calculation step has a step size of 0.002s, and each step has a maximum of 20 iterations. After the calculation, the time-history aerodynamic forces and aerodynamic moments acting on the train are extracted.

[0026] In this scheme, applying variable wind loads to the rail vehicle improves the realism and accuracy of wind load simulation; by using a transient solver of the finite volume method, a turbulence model, and a pressure-velocity coupling algorithm, accurate input is provided for subsequent fluid-structure interaction and rigid-flexible coupling analysis.

[0027] In a specific embodiment, the scheme for establishing a rigid-flexible coupled multibody dynamics model of the vehicle based on the vehicle structure and performance parameters, setting observation points in the rigid-flexible coupled multibody dynamics model, and recording the initial coordinate values ​​of each observation point is as follows: Step 1: Based on the structural performance parameters of the rail vehicle, build a multi-rigid-body dynamics model, construct finite element models of the car body, frame, and wheelsets, perform elasticization on the finite element models of the car body, frame, and wheelsets to form elastic body models of the frame and wheelsets, and import the elastic body models into the multi-rigid-body dynamics model to form a rigid-flexible coupled multi-body dynamics model of the vehicle. Specifically, this solution is based on the theory of vehicle multibody system dynamics and establishes a refined model that considers the flexible deformation of key components such as the vehicle body. Based on the actual structural performance parameters of the rail vehicle (such as mass, inertia, suspension parameters, etc.), a multi-rigid-body system model is built in multibody dynamics software (such as Simpack, UM). The topology of this model is as follows: Figure 4 As shown, the model takes into account the nonlinear characteristics of components such as anti-hunting dampers and lateral stops. To further improve model accuracy, finite element models of the vehicle body, frame, and wheelsets were established based on the vehicle's three-dimensional geometric model. Flexible processing was applied to the vehicle body, frame, and wheelsets, such as... Figure 5 , Figure 6 and Figure 7 As shown, elasticization is performed to generate a flexible body file for multibody dynamics, i.e., an elastic body model, which is then imported into the aforementioned multi-rigid body dynamics model to replace the corresponding rigid components, ultimately forming a rigid-flexible coupling dynamics model of the vehicle. Multibody system dynamics simulation technology has become an important engineering analysis tool. Constructing rigid body dynamics models and finite element models of vehicles is a conventional technique in this field and will not be described in detail. Flexible processing of finite element models is a common technique in simulation. The core of this solution lies in integrating the flexible elastic body model into the rigid body model to achieve a more accurate and realistic simulation. The rigid body dynamics model of the vehicle is constructed using Simpack, while the construction and flexible processing of the finite element model are implemented using ANSYS. The elastic body model is input into Simpack and fused with the rigid body dynamics model. Those skilled in the art know how to use Simpack and ANSYS to construct and fuse models, so specific details will not be provided. Step 2: Set up the observation points in the rigid-flexible coupled multibody dynamics model of the vehicle, including: Five characteristic sections are selected along the longitudinal direction of the car body: the first end, the center of the first bogie, the middle of the car body, the center of the second bogie, and the second end, to characterize the overall bending and torsional deformation of the car body; n observation points that can cover the entire outline of the car body are arranged on the above sections. Specifically, unlike traditional methods that only consider the car body as a rigid body, this method, based on a rigid-flexible coupling model, considers the car body's flexibility. The maximum vertical and lateral displacements of the car body may occur at the following locations: besides the two longitudinal ends and the middle section of the car body, the displacements may also occur in the reference plane region where the centerlines of the two bogies are located. Therefore, based on these displacement distribution characteristics, five characteristic sections are selected along the longitudinal direction of the car body for observation. The specific observation locations are as follows: Figure 8 As shown, observation points are arranged at the following cross-sections: one at the end of the car body (F), one at the center of the bogie (F1), the middle of the car body (M), the center of the second bogie (B1), and the end of the second car body (B). Based on the maximum profile of the car body, observation points are arranged on each characteristic cross-section, as follows: Figure 9 As shown, taking the center section (F1) of a bogie as an example, a strategy of connecting external feature points was adopted, selecting a total of 15 symmetrically distributed control points (numbers 1-15). Among them, the horizontal coordinates of points 1-6 on the right increase progressively, with point 6 being the point of maximum car body width; the horizontal coordinates of points 6 to 8 decrease progressively; below point 8, the car body contracts inward. Points 9-15 on the left are symmetrically distributed with the right side. The initial coordinate values ​​of each observation point are recorded in Table 1. Table 1 Initial coordinates of the car body reference point (center section F1 of the bogie).

[0028] This approach constructs a rigid-flexible coupled multibody dynamics model of the vehicle, whose core advantage lies in achieving high-fidelity simulation of the system's dynamic response. In this model, forces can be transmitted through the elastic deformation of the flexible body, resulting in more realistic displacement, velocity, and acceleration responses. By seamlessly integrating modal order reduction with a highly efficient multibody dynamics solver, computational efficiency is significantly improved while maintaining engineering calculation accuracy.

[0029] In a specific embodiment, the aerodynamic forces and aerodynamic torques are input into the rigid-flexible coupled multibody dynamics model of the vehicle, and dynamic simulations of the rigid-flexible coupled multibody dynamics model of the vehicle under multiple working conditions are performed to calculate the dynamic displacement of each observation point under each working condition, and then obtain the maximum value of the dynamic displacement of each observation point. Simpack is used to perform dynamic simulations of the rigid-flexible coupled multibody dynamics model of the vehicle under various working conditions in order to calculate the dynamic displacement of each observation point under each working condition. Each working condition refers to the various working conditions that the rail vehicle will encounter during operation, such as the operating state of the vehicle under common working conditions such as different speeds, different lines, and different wind speeds. The specific parameters of the working conditions are common data in the field of vehicle dynamics simulation and are common knowledge in the field of human skills. Specifically, aerodynamic force and aerodynamic moment time history data are applied as external loads to the rigid-flexible coupled multibody dynamics model of the vehicle. Dynamic simulations were performed under set operating conditions (such as different lines, different speeds, and different wind speeds) to accurately obtain the lateral (Y-direction) and vertical (Z-direction) dynamic displacement changes of all observation points (such as points 1-15) at each cross section. Under typical vehicle operating conditions, the lateral and vertical dynamic displacement changes of each observation point in each section are accurately obtained. For observation points with the same number on the section, their lateral and vertical dynamic displacement values ​​are compared, and the largest lateral and vertical displacement value is selected as the maximum lateral and vertical dynamic displacement value of the observation points with the same number on the design section.

[0030] In this scheme, the maximum dynamic displacement is calculated to ensure that the final generated dynamic envelope meets safety standards.

[0031] In a specific embodiment, the scheme for calculating the static displacement of each observation point based on vehicle manufacturing and installation tolerances, wear, and suspension parameter characteristics is as follows: By combining vehicle manufacturing and installation tolerances with suspension parameters, the lateral and vertical static displacements at each cross-section observation point are calculated. Installation tolerances primarily consider the overall tolerances after assembly, while wear mainly considers the vertical and lateral wear between the wheel and rail. Specifically, static displacement consists of manufacturing and assembly tolerances of railway locomotives and rolling stock, wheel and rail wear, track deviations, and other displacement factors that were not included or were not fully included in the dynamic displacement analysis and calculation. It can be directly calculated by linear accumulation. Static displacement calculation is a conventional technical means in the field of dynamic envelope generation, so the calculation of static displacement will not be explained in detail.

[0032] In a specific embodiment, the initial coordinate values, maximum dynamic displacement, and static displacement of each observation point are superimposed to obtain the dynamic envelope boundary coordinates of each observation point. The scheme for connecting the dynamic envelope boundary coordinates of each observation point to generate the dynamic envelope boundary of the entire rail vehicle is as follows: The initial coordinates, static displacement, and maximum dynamic displacement of each observation point are superimposed to calculate the dynamic envelope clearance coordinates. Based on the geometric characteristics of the vehicle profile, the combination of directions of the maximum dynamic displacement differs for observation points in different regions. For example, for a point in the middle of the roof (e.g., point 1), the maximum displacement needs to be found laterally to both sides and vertically upwards; for points on the upper part of the sidewall (e.g., points 2-6), the maximum lateral displacement needs to be found laterally to the right and vertically upwards; for points on the lower part of the sidewall (e.g., points 7-8), the maximum lateral displacement needs to be found laterally to the right and vertically downwards. After calculating the dynamic envelope clearance for all observation points according to the rules, connecting these coordinate points allows for the drawing of the complete dynamic envelope clearance of the rail vehicle under specific operating conditions. This dynamic envelope is directly used to determine the minimum safe clearance between the vehicle and fixed facilities along the line such as tunnels, platforms, and signaling equipment, as well as between passing trains, providing a precise basis for the safe operation of vehicles and the formulation of railway clearance standards.

[0033] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for calculating the dynamic clearance of rail vehicles based on fluid-structure interaction and rigid-flexible coupling, characterized in that, include: S1: Construct a three-dimensional geometric model and flow field computational domain for the rail vehicle, and set the flow field boundary conditions of the flow field computational domain based on the three-dimensional geometric model; S2: Apply time-varying wind load to the rail vehicle under the flow field boundary conditions. Introduce the transient solver of the finite volume method, the turbulence model and the pressure-velocity coupling algorithm in the flow field calculation domain to solve the aerodynamic forces and aerodynamic torques of the vehicle under the time-varying wind load. S3: Establish a rigid-flexible coupled multibody dynamics model of the vehicle based on the vehicle structure and performance parameters, set the observation points in the rigid-flexible coupled multibody dynamics model of the vehicle, and record the initial coordinate values ​​of each observation point; S4: Input the aerodynamic force and aerodynamic torque into the rigid-flexible coupled multibody dynamics model of the vehicle, perform dynamic simulation of the rigid-flexible coupled multibody dynamics model of the vehicle under multiple working conditions, calculate the dynamic displacement of each observation point under each working condition, and then obtain the maximum value of the dynamic displacement of each observation point. S5: Calculate the static displacement of each observation point based on vehicle manufacturing and installation tolerances, wear and suspension parameter characteristics; S6: The initial coordinates, maximum dynamic displacement, and static displacement of each observation point are superimposed to obtain the dynamic envelope boundary coordinates of each observation point. The dynamic envelope boundary coordinates of each observation point are then connected to generate the dynamic envelope boundary of the entire rail vehicle.

2. The method for calculating the dynamic clearance of rail vehicles based on fluid-structure interaction and rigid-flexible coupling according to claim 1, characterized in that, Based on a three-dimensional geometric model, the flow field boundary conditions of the computational domain are set, including: The front direction of the rail vehicle is set as the front of the flow field calculation domain, the side of the flow direction in the flow field calculation domain is set as the velocity inlet, the side opposite and adjacent to the velocity inlet is set as the pressure outlet, and the top and bottom surfaces are set as symmetrical boundaries.

3. The method for calculating the dynamic clearance of rail vehicles based on fluid-structure interaction and rigid-flexible coupling according to claim 2, characterized in that, Time-varying wind load conditions are applied to the rail vehicle at the velocity inlet using a custom wind field function.

4. The method for calculating the dynamic clearance of rail vehicles based on fluid-structure interaction and rigid-flexible coupling according to claim 1, characterized in that, A rigid-flexible coupled multibody dynamics model of the vehicle is established based on the vehicle's structure and performance parameters, including: Based on the structural performance parameters of the rail vehicle, a multi-rigid-body dynamics model is built, and finite element models of the car body, frame, and wheelsets are constructed. The finite element models of the car body, frame, and wheelsets are elasticized to form elastic body models of the frame and wheelsets. The elastic body models are then imported into the multi-rigid-body dynamics model to form a rigid-flexible coupled multi-body dynamics model of the vehicle.

5. The method for calculating the dynamic clearance of rail vehicles based on fluid-structure interaction and rigid-flexible coupling according to claim 1, characterized in that, Setting up observation points in the rigid-flexible coupled multibody dynamics model of the vehicle, including: Select characteristic sections along the longitudinal direction of the car body: the end of the first bogie, the center of the first bogie, the middle of the car body, the center of the second bogie, and the end of the second bogie. On each of the aforementioned characteristic sections, n observation points are set up to cover the entire outline of the vehicle body.

6. The method for calculating the dynamic clearance of rail vehicles based on fluid-structure interaction and rigid-flexible coupling according to claim 2, characterized in that, Simpack was used to perform dynamic simulations of the rigid-flexible coupled multibody dynamics model of the vehicle under multiple working conditions in order to calculate the dynamic displacement of each observation point under each working condition.

7. The method for calculating the dynamic clearance of rail vehicles based on fluid-structure interaction and rigid-flexible coupling according to claim 3, characterized in that, The time-varying wind load conditions include modified "Chinese hat" type sudden wind, sinusoidal gust wind, and gradual gust wind; The modified custom wind field function for the "China hat" type sudden wind condition is shown in formula (1). （1） Where t represents the duration of the wind condition; The custom function for the wind field of sinusoidal gusts is shown in formula (2). （2） The custom function for the wind field of the gradual gust is shown in formula (3). （3）。

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