Self-adaptive step length adjusting method and system based on axle coupling system

Abstract

The invention relates to a self-adaptive step length adjustment method based on an axle coupling system, and the method comprises the steps: carrying out the real-time analysis based on the time-history response of a wheel-rail contact force obtained by a vehicle subsystem, so as to judge whether the stage of the wheel-rail contact force is a dramatic change stage or a slow change stage; dynamically adjusting the time step length for the bridge subsystem based on the stage of the wheel-rail contact force; if the wheel-rail contact force is in the dramatic change stage, the time step length of the vehicle subsystem is refined or maintained to serve as the time step length of the bridge subsystem; and if the wheel-rail contact force is in the slowly changing stage, the time step length of the vehicle subsystem is amplified to serve as the time step length of the bridge subsystem. According to the method, unnecessary fine calculation in the non-critical time period is avoided while the calculation precision in the critical time period is ensured, and the calculation efficiency is greatly improved.

Description

Technical Field

[0001] This invention relates to the field of vehicle-bridge coupled vibration analysis technology, specifically to an adaptive step size adjustment method and system based on a vehicle-bridge coupled system. Background Technology

[0002] Vehicle-bridge coupled vibration analysis is a key technology for evaluating the safety of train operation and the dynamic performance of bridge structure when trains cross bridges. Its core lies in solving the complex time-varying system formed by the coupling of the vehicle subsystem and the bridge subsystem through nonlinear wheel-rail contact relationship.

[0003] Due to the complex suspension system and strong nonlinear wheel-rail contact, the vehicle subsystem requires extremely high precision in its integration time step, typically requiring very small time steps (e.g., 0.001 to 0.0001 seconds) to accurately capture high-frequency vibrations and transient impact responses. However, the bridge subsystem usually contains tens of thousands of elements, with massive mass and stiffness matrices. Directly loading the high-precision, small-step wheel-rail contact force time history obtained from solving the vehicle subsystem onto the bridge model would lead to a surge in computational steps, making the solution process extremely time-consuming and computationally inefficient.

[0004] In related technologies, even if a fixed and compromised time step is used throughout the analysis process, it may still lead to low computational accuracy in certain critical periods or unnecessary fine calculations in non-critical periods, resulting in low computational efficiency. Summary of the Invention

[0005] This application provides an adaptive step size adjustment method and system based on a vehicle-bridge coupling system, which solves the technical problem of difficulty in balancing computational accuracy and computational efficiency in related technologies.

[0006] This application provides an adaptive step size adjustment method based on a vehicle-bridge coupling system, which includes the following steps: Based on the time history response of wheel-rail contact force obtained from the vehicle subsystem, real-time analysis is performed to determine whether the wheel-rail contact force is in a rapidly changing stage or a gradually changing stage. The time step for dynamic adjustment of the bridge subsystem is based on the stage of the wheel-rail contact force. If the wheel-rail contact force is in a stage of drastic change, then the time step of the vehicle subsystem is refined or maintained as the time step of the bridge subsystem. If the wheel-rail contact force is in a gradually changing phase, then the time step of the vehicle subsystem is amplified as the time step of the bridge subsystem.

[0007] In one implementation, the real-time analysis of the wheel-rail contact force time history response obtained from the vehicle subsystem to determine whether the wheel-rail contact force is in a rapidly changing or gradually changing stage includes: Based on the forward direction of the wheel-rail contact force, a time window is set with the wheel-rail contact force within a preset time range, and the standard deviation of the wheel-rail contact force within the time window is calculated. If the standard deviation is greater than the preset upper limit, the wheel-rail contact force is determined to be in a stage of drastic change.

[0008] In one implementation, the real-time analysis of the wheel-rail contact force time history response obtained from the vehicle subsystem to determine whether the wheel-rail contact force is in a rapidly changing or gradually changing stage includes: Based on the forward direction of the wheel-rail contact force, a time window is set with the wheel-rail contact force within a preset time range, and the standard deviation of the wheel-rail contact force within the time window is calculated. If the standard deviation of multiple consecutive time windows is less than the preset lower limit, the wheel-rail contact force is determined to be in a gradually changing stage.

[0009] In one implementation, the preset time range is 0.1s.

[0010] In one implementation, the plurality is 4-6.

[0011] In one embodiment, amplifying the time step of the vehicle subsystem as the time step of the bridge subsystem includes: The wheel-rail contact force time history of the vehicle subsystem is interpolated to form an equivalent load time history with a time step magnified by N times. The time step of the bridge subsystem is N times the time step of the vehicle subsystem, where N is 5-10.

[0012] In one embodiment, amplifying the time step of the vehicle subsystem as the time step of the bridge subsystem further includes: Set a maximum step size for the time step of the bridge subsystem.

[0013] In one implementation, when the time history response of the wheel-rail contact force is obtained based on the vehicle subsystem, the time step of the vehicle subsystem is set to a fixed value.

[0014] In one implementation, the vehicle subsystem is calculated based on an implicit numerical integration method to obtain the time history response of the wheel-rail contact force.

[0015] This application also provides an adaptive step size adjustment system based on a vehicle-axle coupling system, which applies the adaptive step size adjustment method based on a vehicle-axle coupling system as described in any of the above claims, and includes: The real-time analysis module is configured to perform real-time analysis based on the wheel-rail contact force time history response obtained from the vehicle subsystem to determine whether the wheel-rail contact force is in a rapidly changing or gradually changing stage. The step size adjustment module is configured to dynamically adjust the time step of the bridge subsystem based on the stage of the wheel-rail contact force. If the wheel-rail contact force is in a stage of drastic change, then the time step of the vehicle subsystem is refined or maintained as the time step of the bridge subsystem. If the wheel-rail contact force is in a gradually changing phase, then the time step of the vehicle subsystem is amplified as the time step of the bridge subsystem.

[0016] The beneficial effects of the technical solutions provided in this application include: This application provides an adaptive time step adjustment method and system based on a vehicle-bridge coupled system. It uses real-time analysis of the time history response of wheel-rail contact force as the basis for time step adjustment, extracting the dynamic variation characteristics of wheel-rail interaction forces, automatically identifying the intensity of wheel-rail interaction, and adaptively adjusting the integration time step of the bridge subsystem. During the gradual load change phase, a larger time step is used to improve efficiency; during the rapid load change phase (such as when the wheel just contacts or leaves the bridge surface), the time step is automatically reduced to ensure computational accuracy. This achieves "on-demand allocation" of computational resources, ensuring computational accuracy and reliability during critical periods while avoiding unnecessary detailed calculations during non-critical periods, significantly improving computational efficiency. The adjustment method provided in this application serves as a general framework with strong applicability, and can be combined with various existing numerical integration methods (such as the Newmark-β method and refined integration methods) and vehicle-bridge coupled models, making it easy to integrate into existing simulation platforms or programs. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a flowchart illustrating the steps of an adaptive step size adjustment method based on a vehicle-bridge coupling system in one embodiment of the present invention.

[0019] Figure 2 This is a schematic diagram of the time history response characteristics of wheel-rail contact force on different tracks in one embodiment of the present invention. Detailed Implementation

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

[0021] This application provides an adaptive step size adjustment method based on a vehicle-bridge coupled system, which can solve the technical problem of difficulty in balancing computational accuracy and computational efficiency in related technologies, and is particularly suitable for dynamic response analysis of vehicle-bridge coupled vibration systems.

[0022] like Figure 1 As shown, Figure 1 This is a flowchart illustrating the steps of an adaptive step size adjustment method based on a vehicle-bridge coupling system in one embodiment of the present invention.

[0023] This embodiment provides an adaptive step size adjustment method based on a vehicle-bridge coupling system, which includes the following steps: Step S1: Based on the time history response of the wheel-rail contact force obtained from the vehicle subsystem, perform real-time analysis to determine whether the wheel-rail contact force is in a rapidly changing stage or a gradually changing stage. Step S2: The time step of the bridge subsystem is dynamically adjusted based on the stage of wheel-rail contact force. If the wheel-rail contact force is in a stage of drastic change, then the time step of the vehicle subsystem is refined or maintained as the time step of the bridge subsystem. If the wheel-rail contact force is in a gradually changing phase, then the time step of the vehicle subsystem is amplified as the time step of the bridge subsystem.

[0024] This embodiment provides an adaptive time step adjustment method based on a vehicle-bridge coupled system. It uses real-time analysis of the wheel-rail contact force time history response as the basis for time step adjustment, extracting the dynamic variation characteristics of the wheel-rail interaction force, automatically identifying the intensity of wheel-rail interaction, and adaptively adjusting the integration time step of the bridge subsystem. During the gradual load change phase, a larger time step is used to improve efficiency; during the rapid load change phase (such as when the wheel just contacts or leaves the bridge surface), the time step is automatically reduced to ensure computational accuracy. This achieves "on-demand allocation" of computational resources, ensuring computational accuracy and reliability during critical periods while avoiding unnecessary fine calculations during non-critical periods, significantly improving computational efficiency. The adjustment method provided in this application serves as a general framework with strong applicability. It can be combined with various existing numerical integration methods (such as the Newmark-β method and fine integration methods) and vehicle-bridge coupled models, and is easily integrated into existing simulation platforms or programs.

[0025] The following provides a detailed explanation of each step.

[0026] In one embodiment, when obtaining the time history response of the wheel-rail contact force based on the vehicle subsystem, the time step dt_v of the vehicle subsystem is set to a fixed value, such as dt_v = 0.001 s, to ensure the accuracy of the solution of the nonlinear wheel-rail contact force. Of course, it can be set to other smaller values ​​depending on the specific working conditions.

[0027] In one embodiment, the vehicle subsystem is calculated based on implicit numerical integration to obtain the wheel-rail contact force time history response.

[0028] Specifically, based on implicit numerical integration methods (such as the Newmark-β method), an initial wheel-rail contact point state is assumed (e.g., the first iteration usually assumes that the bridge has not deformed). During the entire analysis period, the motion equations of the vehicle subsystem are solved with a preset small time step (e.g., 0.001 seconds) that meets the accuracy requirements of nonlinear wheel-rail contact. The motion state (displacement, velocity, acceleration) of the train at each moment and the fine time history data of the wheel-rail interaction force are calculated as the wheel-rail contact force time history response F(t) under the fine time step.

[0029] In one embodiment, step S1, performing real-time analysis based on the wheel-rail contact force time history response obtained from the vehicle subsystem to determine whether the wheel-rail contact force is in a rapidly changing or gradually changing stage, includes: Based on the direction of wheel-rail contact force loading, a time window is set with the wheel-rail contact force within a preset time range, and the standard deviation of the wheel-rail contact force within the time window is statistically analyzed.

[0030] If the standard deviation is greater than the preset upper limit, the wheel-rail contact force is determined to be in a stage of drastic change.

[0031] In one embodiment, step S1, performing real-time analysis based on the wheel-rail contact force time history response obtained from the vehicle subsystem to determine whether the wheel-rail contact force is in a rapidly changing or gradually changing stage, includes: Based on the direction of wheel-rail contact force loading, a time window is set with the wheel-rail contact force within a preset time range, and the standard deviation of the wheel-rail contact force within the time window is statistically analyzed. If the standard deviation of multiple consecutive time windows is less than the preset lower limit, the wheel-rail contact force is determined to be in a gradually changing stage.

[0032] In one embodiment, the preset time range is 0.1s, but other values ​​are also possible.

[0033] In one embodiment, there are 4 to 6 of them.

[0034] Specifically, a threshold for wheel-rail contact force fluctuation is set as the upper and lower limits, which can be determined based on the characteristic value amplitude generated by the train during the random process. Based on the direction of wheel-rail contact force loading (i.e., the direction of wheel movement), a time window is set for the wheel-rail contact force within a 0.1s interval. When the standard deviation of the wheel-rail contact force within the 0.1s time window is greater than the upper limit, it indicates a strong impact from the wheel-rail contact force, and the wheel-rail contact force is determined to be in a rapidly changing phase. The time step of the vehicle subsystem is refined or maintained as the time step of the bridge subsystem; the shorter the time step, the stronger the characteristic and the more obvious the wheel-rail contact force time history. When the standard deviation of five consecutive time windows is less than the lower limit, it indicates that the wheel-rail contact force fluctuation within the preceding and following time windows is not significant, and the wheel-rail contact force is determined to be in a gradually changing phase. A sparsity-enlarging method is used to expand the time step of the vehicle subsystem for interpolation to generate new wheel-rail contact forces.

[0035] Because the wheel-rail contact force is moving forward and constantly changing during actual vehicle operation, the standard deviation is a numerical value that summarizes the degree to which the wheel-rail contact force deviates from its average level over a period of time. It intuitively reflects the "instability" of the force value and quantifies the intensity of the fluctuation of wheel-rail interaction within a specific time period. Thus, the standard deviation of the wheel-rail contact force is used as a judgment threshold to more accurately reflect the dynamic response state of the vehicle-bridge coupling system.

[0036] The above scheme performs real-time analysis based on the time history response of wheel-rail contact force, extracts its dynamic fluctuation characteristics, determines the wheel-rail force characteristics by using the slip window standard deviation method, and sets clear physical indicators. The wheel-rail force fluctuation threshold is used as the preset upper and lower limits to control the step size switching. The logic is clear, the accuracy is controllable, avoids human experience intervention, and ensures the calculation accuracy of key complex dynamic response phenomena.

[0037] In step S2, if the wheel-rail contact force is in a stage of dramatic change, it indicates that the current stage is a critical stage with strong wheel-rail impact. In this case, the time step dt_b of the bridge subsystem is kept consistent with the time step dt_v of the vehicle subsystem. The same high-precision small step size is maintained for the solution, i.e., dt_b = dt_v, to ensure the accurate transmission of the impact effect. Of course, the time step can be further refined according to the requirements.

[0038] If the wheel-rail contact force is in a gradually changing phase, it indicates that the current situation is in a non-critical phase with a stable response. Therefore, the time step of the vehicle subsystem should be increased, and the time step of the bridge subsystem should be N times the time step of the vehicle subsystem.

[0039] In one embodiment, amplifying the time step of the vehicle subsystem as the time step of the bridge subsystem includes: The wheel-rail contact force time history of the vehicle subsystem is interpolated to form an equivalent load time history with a time step magnified by N times. This load time history is then applied to the bridge subsystem, where the time step of the bridge subsystem is N times the time step of the vehicle subsystem, and N is an integer from 5 to 10. For example, dt_b = N * dt_v (N is 10). In one embodiment, amplifying the time step of the vehicle subsystem as the time step of the bridge subsystem further includes: Set a maximum time step, such as 0.01s, for the bridge subsystem to avoid losing important dynamic components.

[0040] When the adaptively adjusted load and time step are applied to the bridge subsystem, implicit integration methods such as the Newmark-β method can be used to independently solve the dynamic equations of the bridge subsystem throughout the entire analysis period, obtaining the dynamic response of the bridge at each point (such as displacement and acceleration time histories). The wheel-rail contact force calculated in the current iteration step is compared with that in the previous iteration step, and the error between the two over the entire time history is checked to see if it is less than a preset convergence threshold. This constitutes one complete calculation cycle. The above steps are repeated; if the convergence value is less than the given threshold, the entire dynamic analysis ends.

[0041] This embodiment also provides an adaptive step size adjustment system based on a vehicle-bridge coupling system, which applies the above-mentioned adaptive step size adjustment method based on a vehicle-bridge coupling system and includes: The real-time analysis module is configured to perform real-time analysis based on the wheel-rail contact force time history response obtained from the vehicle subsystem to determine whether the wheel-rail contact force is in a rapidly changing or gradually changing stage. The step size adjustment module is configured to dynamically adjust the time step of the bridge subsystem based on the stage of wheel-rail contact force. If the wheel-rail contact force is in a stage of drastic change, then the time step of the vehicle subsystem is refined or maintained as the time step of the bridge subsystem. If the wheel-rail contact force is in a gradually changing phase, then the time step of the vehicle subsystem is amplified as the time step of the bridge subsystem.

[0042] The functions of each module have been explained in the previous text and will not be repeated here.

[0043] The following is an illustration through a specific example.

[0044] Take, for example, a high-speed train crossing a long-span bridge.

[0045] Bridge Model: A suspension bridge with a main span of 2498 meters. The bridge subsystem is simulated using a finite element model, with spatial beam elements simulating the main girder and towers, and rod elements simulating the stay cables. The model contains approximately 28,526 elements in total, with a large number of nodal degrees of freedom.

[0046] Vehicle Model: A multibody dynamics model of an 8-car high-speed train is adopted. Each car considers the heave, pitch, yaw, roll, and yaw motions of the car body, bogies, and wheelsets, simplifying it into a system with 35 degrees of freedom. The vehicle subsystem is solved using the implicit Newmark-β method, with the basic parameters set as β=0.25 and γ=0.5.

[0047] Taking the power spectrum of track irregularities on a low-interference railway line in Germany as an example, an equivalent algorithm based on the frequency domain power spectrum is used to simulate the time-domain samples of the irregularities. Random irregularities are introduced into the vehicle model as system excitations. A large torsional irregularity is introduced at 180-190m on the bridge deck to cause train derailment, and the wheel-rail force time history response at 150m-250m is obtained, such as... Figure 2 As shown. Figure 2 (a) in the diagram represents the time history response characteristics of wheel-rail contact force of different left wheels on different tracks; Figure 2 (b) in the diagram represents the time history response characteristics of wheel-rail contact force of different right wheels on different tracks.

[0048] When the wheels enter the twisted and uneven section (as shown in the figure at position 180-190 m), the wheel-rail system experiences a significant dynamic impact. During this process, due to the lateral roll motion of the vehicle body, the impact between the left and right wheels and rails exhibits asynchronous characteristics: the normal force of the right wheel increases sharply, while the left wheel experiences a significant reduction in load, and even momentary wheel-rail separation occurs, meaning the contact force of the left wheel drops to zero. Therefore, the area with significant wheel-rail impact is identified as the abrupt change phase. Conversely, the wheel-rail contact force in other sections fluctuates relatively little around the mean, which can be identified as the gradual change phase.

[0049] This embodiment provides an adaptive step size adjustment method based on a vehicle-bridge coupling system, which includes the following steps: Step S1: Based on the time history response of the wheel-rail contact force obtained from the vehicle subsystem, perform real-time analysis to determine whether the wheel-rail contact force is in a rapidly changing stage or a gradually changing stage.

[0050] Set the time step dt_v of the vehicle subsystem as the base step, dt_v = 0.001 s.

[0051] The wheel-rail force fluctuation threshold is set to 20kN-50kN. Based on the wheel-rail contact force loading direction (i.e., the direction of wheel movement), the wheel-rail contact force within a range of 0.1s (i.e., 100 data points) is set as a time window. When the standard deviation of the wheel-rail contact force within the 0.1s time window is ≥ 50kN, it is determined that the system has entered a stage of intense dynamic interaction and rapid change. When the standard deviation of 5 consecutive time windows is ≤ 20 kN, the system response is determined to be stable and enter a stage of gradual change.

[0052] Step S2: The time step of the bridge subsystem is dynamically adjusted based on the stage of wheel-rail contact force. If the wheel-rail contact force is in a stage of drastic change, then the time step dt_b of the bridge subsystem is equal to the time step dt_v of the vehicle subsystem. If the wheel-rail contact force is in a gradually changing phase, then the time step of the bridge subsystem is dt_b = N * dt_v.

[0053] When converting from a fine step size to a coarse step size, a linear interpolation method is used to convert the high-precision wheel-rail force time history data into the equivalent load at the corresponding coarse step size.

[0054] Phase 1: Dramatic Change Phase (L = 0~10 m) Scenario: The locomotive has just driven onto the bridge. Due to the difference in stiffness between the approach bridge and the main bridge, as well as the unevenness of the rail surface, an initial impact effect is triggered.

[0055] Process: Monitoring data showed that the standard deviation of the wheel-rail contact force reached 52.5 kN within a 0.1-second time window, exceeding the threshold. The bridge subsystem was solved using a step size of dt_b = 0.001 s to accurately capture the peak impact value of the bending moment at the mid-span section of the bridge during this period.

[0056] Phase Two: Gradual Change Phase (L = 10~180m) Scenario: The train is now completely on the bridge and is traveling at a constant high speed, with smooth changes in wheel-rail force.

[0057] Process: Monitoring data showed that the standard deviation of the wheel-rail contact force remained stable between 2.8 kN and 13.5 kN for several consecutive time windows. The time step was switched to dt_b = 0.1 s. Within this 2-second physical time, the vehicle subsystem required 2000 calculations, while the bridge subsystem only required 20 calculations, significantly improving computational efficiency.

[0058] Phase 3: Dynamic Switching Scenario: When the train passes near a large tortuous irregularity (190m), the wheel-rail contact force fluctuates again due to local stiffness changes, or when the train brakes / accelerates slightly.

[0059] Process: The method provided in this application embodiment monitors and responds quickly in real time. Once the standard deviation exceeds the threshold of 50 kN again, it immediately switches back to the small step mode to ensure the calculation accuracy during the critical dynamic response period.

[0060] It should be noted that the sequence numbers of the embodiments in this application are merely for descriptive purposes and do not represent the superiority or inferiority of the embodiments. The terms "comprising" and "having," and any variations thereof, in the specification, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or devices. The terms "first," "second," and "third," etc., are used to distinguish different objects, etc., and do not represent a sequential order, nor do they limit "first," "second," and "third" to different types.

[0061] In the description of the embodiments of this application, terms such as "exemplary," "for example," or "for instance" are used to indicate examples, illustrations, or explanations. Any embodiment or design described as "exemplary," "for example," or "for instance" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplary," "for example," or "for instance" is intended to present the relevant concepts in a concrete manner.

[0062] In the description of the embodiments of this application, unless otherwise stated, " / " means "or". For example, A / B can mean A or B. The "and / or" in the text is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, and B exists alone. In addition, in the description of the embodiments of this application, "multiple" means two or more.

[0063] In some processes described in the embodiments of this application, multiple operations or steps are included in a specific order. However, it should be understood that these operations or steps may not be executed in the order they appear in the embodiments of this application, or they may be executed in parallel. The sequence number of the operation is only used to distinguish the different operations, and the sequence number itself does not represent any execution order. In addition, these processes may include more or fewer operations, and these operations or steps may be executed sequentially or in parallel, and these operations or steps may be combined.

[0064] The above are merely preferred embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. An adaptive step size adjustment method based on a vehicle-bridge coupling system, characterized in that, It includes the following steps: Based on the time history response of wheel-rail contact force obtained from the vehicle subsystem, real-time analysis is performed to determine whether the wheel-rail contact force is in a rapidly changing stage or a gradually changing stage. The time step for dynamic adjustment of the bridge subsystem is based on the stage of the wheel-rail contact force. If the wheel-rail contact force is in a stage of drastic change, then the time step of the vehicle subsystem is refined or maintained as the time step of the bridge subsystem. If the wheel-rail contact force is in a gradually changing phase, then the time step of the vehicle subsystem is amplified as the time step of the bridge subsystem.

2. The adaptive step size adjustment method based on a vehicle-bridge coupling system as described in claim 1, characterized in that, The real-time analysis of the wheel-rail contact force time history response obtained from the vehicle subsystem to determine whether the wheel-rail contact force is in a rapidly changing or gradually changing stage includes: Based on the forward direction of the wheel-rail contact force, a time window is set with the wheel-rail contact force within a preset time range, and the standard deviation of the wheel-rail contact force within the time window is calculated. If the standard deviation is greater than the preset upper limit, the wheel-rail contact force is determined to be in a stage of drastic change.

3. The adaptive step size adjustment method based on a vehicle-bridge coupling system as described in claim 1, characterized in that, The real-time analysis of the wheel-rail contact force time history response obtained from the vehicle subsystem to determine whether the wheel-rail contact force is in a rapidly changing or gradually changing stage includes: Based on the forward direction of the wheel-rail contact force, a time window is set with the wheel-rail contact force within a preset time range, and the standard deviation of the wheel-rail contact force within the time window is calculated. If the standard deviation of multiple consecutive time windows is less than the preset lower limit, the wheel-rail contact force is determined to be in a gradually changing stage.

4. The adaptive step size adjustment method based on a vehicle-bridge coupling system as described in claim 2 or 3, characterized in that, The preset time range is 0.1s.

5. The adaptive step size adjustment method based on a vehicle-bridge coupling system as described in claim 2 or 3, characterized in that, The number of items is 4-6.

6. The adaptive step size adjustment method based on a vehicle-bridge coupling system as described in claim 1, characterized in that, The step of amplifying the time step of the vehicle subsystem as the time step of the bridge subsystem includes: The wheel-rail contact force time history response of the vehicle subsystem is interpolated to form an equivalent load time history with a time step magnified by N times. The time step of the bridge subsystem is N times the time step of the vehicle subsystem, where N is 5-10.

7. The adaptive step size adjustment method based on a vehicle-bridge coupling system as described in claim 6, characterized in that, The method of amplifying the time step of the vehicle subsystem as the time step of the bridge subsystem further includes: Set a maximum step size for the time step of the bridge subsystem.

8. The adaptive step size adjustment method based on a vehicle-bridge coupling system as described in claim 1, characterized in that, When obtaining the wheel-rail contact force time history response based on the vehicle subsystem, the time step of the vehicle subsystem is set to a fixed value.

9. The adaptive step size adjustment method based on a vehicle-bridge coupling system as described in claim 8, characterized in that, The vehicle subsystem is calculated using the implicit numerical integration method to obtain the time history response of the wheel-rail contact force.

10. An adaptive step size adjustment system based on a vehicle-bridge coupling system, employing the adaptive step size adjustment method based on a vehicle-bridge coupling system as described in any one of claims 1 to 9, characterized in that, It includes: The real-time analysis module is configured to perform real-time analysis based on the wheel-rail contact force time history response obtained from the vehicle subsystem to determine whether the wheel-rail contact force is in a rapidly changing or gradually changing stage. The step size adjustment module is configured to dynamically adjust the time step of the bridge subsystem based on the stage of the wheel-rail contact force. If the wheel-rail contact force is in a stage of drastic change, then the time step of the vehicle subsystem is refined or maintained as the time step of the bridge subsystem. If the wheel-rail contact force is in a gradually changing phase, then the time step of the vehicle subsystem is amplified as the time step of the bridge subsystem.

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