Vehicle dynamics performance analysis method and system considering suspension parameter performance degradation

Abstract

The invention provides a vehicle dynamics performance analysis method and system considering suspension parameter performance degradation, and relates to the technical field of railway vehicle dynamics, and the method comprises the steps: building a nonlinear Maxwell hydraulic damper model; establishing a vehicle system dynamics model in simulation software based on a vehicle dynamics theory; integrating the nonlinear Maxwell hydraulic damper model into a vehicle system dynamic model, and establishing a vehicle system nonlinear dynamic model considering suspension parameter performance degradation; setting model parameters of the nonlinear Maxwell hydraulic damper to obtain a simulation result; and analyzing the dynamic performance evaluation index of the vehicle so as to complete dynamic performance evaluation of the vehicle under the conditions of actual service mileage and environment temperature. The method effectively reflects the influence of suspension parameter degradation on the dynamic performance of the vehicle, improves the precision of a dynamic simulation model of the railway vehicle and the reasonability of an analysis method, and has important theoretical research significance for innovative design and intelligent operation and maintenance of the railway vehicle.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of vehicle dynamics, in particular, to a vehicle dynamics performance analysis method and system considering performance degradation of suspension parameters. BACKGROUND

[0002] The bogie is the running part of the motor train unit, which plays a major role in bearing, guiding, damping and traction braking, and determines the running speed, running quality and driving safety of the train. The suspension system is an important part of the bogie, which assembles the wheelset, the frame and other components into a whole, and plays a role in positioning, supporting and damping. The suspension system of the bogie of the motor train unit mainly includes primary suspension (located between the wheelset and the frame) and secondary suspension (located between the frame and the vehicle body), and the suspension elements include springs, dampers and limit stops, such as steel springs, air springs, elastic rubber parts, hydraulic dampers and rubber stops. Among them, the hydraulic damper is an important suspension element, including anti-yaw damper, secondary lateral damper, vertical damper, etc., and its dynamic damping and stiffness determine the dynamic performance of the high-speed motor train unit, such as the direct influence on the maximum running speed, running stability and curve passing safety of the train.

[0003] However, the existing vehicle dynamics performance analysis method mainly uses nominal parameters for simulation analysis, without considering the performance degradation characteristics of the suspension elements in the long-term service process, such as the performance degradation of the hydraulic damper, the hardening and softening of the rubber element, etc., and it is difficult to accurately reproduce the actual dynamic problems such as "wobbling", "alarm" and "shaking" that occur in the long-term service process. SUMMARY

[0004] The purpose of the present application is to provide a vehicle dynamics performance analysis method and system considering performance degradation of suspension parameters to improve the above problems. In order to achieve the above purpose, the technical scheme adopted by the present application is as follows: In the first aspect, the present application provides a vehicle dynamics performance analysis method considering performance degradation of suspension parameters, comprising: Performing dynamic parameter testing on two types of high-speed bogie hydraulic dampers, anti-yaw dampers and secondary lateral dampers, on a hydraulic damper dynamic characteristic test bench, to obtain dynamic characteristic data of the hydraulic dampers under different running mileages and environmental temperature conditions; Fusing the dynamic characteristic data with a traditional Maxwell hydraulic damper model to establish a nonlinear Maxwell hydraulic damper model to simulate the frequency variation and amplitude variation nonlinear characteristics of the dynamic damping and stiffness of the damper; Based on the coupling solution of wheel-rail contact force by Hertz theory and Kalker simplified theory, and combined with the bogie components, a vehicle system dynamics model is established in the simulation software based on the theory of vehicle dynamics; Integrate the nonlinear Maxwell hydraulic damper model into the vehicle system dynamics model to establish a vehicle system nonlinear dynamics model considering the performance degradation of suspension parameters; According to the obtained actual service mileage and environmental temperature of the vehicle, the parameters of the nonlinear Maxwell hydraulic damper model are set, and the vehicle system nonlinear dynamics model is driven to perform dynamics simulation to obtain simulation results. Based on the obtained simulation results, the vehicle dynamics performance evaluation index is analyzed to complete the dynamics performance evaluation of the vehicle under the actual service mileage and environmental temperature conditions.

[0005] Preferably, the dynamic parameter test of the anti-snaking damper and the two types of high-speed bogie hydraulic dampers is carried out on the hydraulic damper dynamic characteristic test bench, and the dynamic characteristic data of the dampers under different operating mileages and environmental temperature conditions are obtained, including: Step 11, selecting anti-snaking, two types of lateral and vertical hydraulic dampers with different service mileages as test samples; Step 12, applying a harmonic excitation signal in a displacement control mode on the hydraulic damper dynamic characteristic test bench, and synchronously collecting the force feedback of the actuator as the damper output force signal, wherein the harmonic excitation includes a sine wave with a displacement amplitude and a frequency input by the hydraulic actuator; Step 13, drawing a force-displacement hysteresis curve according to the harmonic excitation signal and the damper output force signal, and calculating the equivalent stiffness and damping coefficient of the damper under the excitation state according to the force-displacement hysteresis curve; Step 14, repeating step S13 to obtain the stiffness and damping under all frequency-amplitude combinations, and placing the test damper in the environmental chamber for ≥24 h, then changing the test temperature, and again completing the corresponding test, replacing the damper with different operating mileages, and repeating steps S12-S14 until the complete dynamic characteristic database under the new and each service mileage state is obtained.

[0006] Preferably, the dynamic characteristic data is fused with the traditional Maxwell hydraulic damper model to establish a nonlinear Maxwell hydraulic damper model to simulate the frequency and amplitude nonlinear characteristics of the dynamic damping and stiffness of the damper, including: Organizing the equivalent damping and equivalent stiffness corresponding to different excitation frequency-displacement amplitude combinations in the dynamic characteristic data as modeling data; Substituting the modeling data into the damping-spring series force element model to obtain the traditional Maxwell hydraulic damper model; Based on the measured data obtained, the spring maximum deformation converted by the phase difference φ is used to construct the nonlinear force-displacement relationship curve, and the speed amplitude is used to construct the nonlinear force-velocity relationship curve, so as to convert the traditional Maxwell hydraulic damper model into a nonlinear Maxwell force element model to match the dynamic working conditions with changing excitation frequency amplitude and duration in vehicle operation. The obtained nonlinear force-displacement relationship curve and nonlinear force-velocity relationship curve are embedded into the Maxwell model and numerical simulation is carried out to reproduce the damper frequency amplitude coupling characteristics, and the frequency variation or amplitude variation results are called as needed to complete the nonlinear characteristic simulation of the dynamic parameters of the damper.

[0007] Preferably, the wheel-rail contact force is solved based on the coupling of Hertz theory and Kalker simplified theory, and the vehicle system dynamics model is established in the simulation software based on vehicle dynamics theory, which includes: The LM type worn tread and the 60 kg / m rail profile are input through the wheel-rail contact geometry module to generate the wheel-rail contact geometry, the wheel-rail normal force and the contact ellipse major and minor axes are calculated by using the Hertz theory, the wheel-rail normal force and the contact ellipse major and minor axes are input into the Kalker simplified theory, and the longitudinal, lateral and spin creep forces are solved in real time to establish the wheelset system dynamics sub-model. Taking the wheelset as the core, the steel spring, the air spring, the rubber joint and the hydraulic damper are integrated according to the "rotating arm-axle box-frame-secondary suspension-car body" hierarchical topology to construct the whole vehicle multi-body dynamics topology. Based on the whole vehicle multi-body dynamics topology, the variable step implicit integrator parameters, the simulation time of 30 s and the sampling frequency of 1000 Hz are configured in the DAP-Rail solver setting module, the German high interference track spectrum is loaded as the track excitation, the initialization and static balance solving are performed, and thus the vehicle system dynamics model is established.

[0008] Preferably, the nonlinear Maxwell hydraulic damper model is integrated into the vehicle system dynamics model to establish a vehicle system nonlinear dynamics model considering the performance degradation of the suspension parameters, which includes: Based on the vehicle system dynamics model, the Maxwell type hydraulic damper force element template of DAP-Rail is called, the fixed stiffness term and the fixed damping term in the force element parameter list are replaced by the nonlinear force-displacement relationship curve and the nonlinear force-velocity relationship curve respectively to generate a nonlinear Maxwell force element of a single damper. The nonlinear Maxwell force element batch is mapped to the hydraulic shock absorber of each part of the vehicle, at least including the anti-snaking shock absorber, the lateral shock absorber and the vertical shock absorber, and the degradation curve data under the corresponding service mileage and the environmental temperature are introduced, the Maxwell parameters of all the suspension shock absorbing elements of the vehicle are replaced by the nonlinear stiffness and damping parameters, so that the vehicle system nonlinear dynamics model considering the performance degradation of the suspension parameters is formed at the topology level; In the DAP-Rail solver setting module, the variable step size implicit integrator parameters, the simulation time length and the sampling frequency are set, the track irregularity excitation is loaded, the initialization and static balance solving are performed, the vehicle system nonlinear dynamics model considering the performance degradation of the suspension parameters is activated and calibrated at the topology level, and the vehicle system nonlinear dynamics model considering the performance degradation of the suspension parameters is generated for the dynamic performance evaluation.

[0009] Preferably, the nonlinear Maxwell hydraulic shock absorber model parameters are set according to the obtained actual service mileage and the environmental temperature of the vehicle, and the vehicle system nonlinear dynamics model is driven to perform dynamic simulation to obtain simulation results, which include: In the vehicle system nonlinear dynamics model, the Maxwell force elements corresponding to all the anti-snaking shock absorbers are positioned, and the obtained actual service mileage and the environmental temperature of the vehicle are input to the port and bound to the external parameter table interface to form a subsequent mileage-temperature interpolation calling channel; According to the to-be-simulated running mileage x, two groups of mileages x1 and x2 closest to x are extracted from the measured database x 1and x 2and the corresponding force-displacement characteristic curves are f k1 and f k2 The reference curve under the mileage x is obtained by linear interpolation; and in the same mileage data subset, the target environmental temperature t is taken as the interpolation point, the two groups of temperatures t1 and t2 closest to t are selected, and the corresponding curves f’ k1 and f’ k2 The corresponding force-velocity characteristic curves are f’ d1 and f’ d2 The temperature interpolation is completed, so that the mileage-temperature coupled force-displacement curve and the force-velocity curve are obtained; The force-displacement curve and the force-velocity curve are input into a nonlinear parameter table of a Maxwell force element of the anti-snaking damper to complete parameter setting, and then a DAP-Rail numerical integration module is started to solve vehicle system dynamics equations, output displacement-velocity time histories of wheelsets, bogies and a vehicle body, and generate wheel-rail vertical force and lateral force time history signals of all wheels to realize vehicle dynamics performance simulation under the working condition and obtain simulation results.

[0010] Preferably, based on the obtained simulation results, vehicle dynamics performance evaluation indexes are analyzed to complete dynamics performance evaluation of the vehicle under actual service mileage and environmental temperature conditions, including: Based on the wheel-rail vertical force and lateral force time history signals of all wheels, vehicle dynamics performance evaluation indexes are calculated to form a quantitative performance database under the working condition; The quantitative performance database is compared with current specifications to identify indexes exceeding threshold values or close to limit values, and the corresponding mileage-temperature working conditions are traced back to determine potential dynamics risk points of the vehicle under actual service mileage and environmental temperature conditions; Using the identified potential dynamics risk points, maintenance or replacement suggestions for different service stages are generated to complete dynamics performance evaluation of the vehicle under actual service mileage and environmental temperature conditions.

[0011] Preferably, the content of analyzing the vehicle dynamics performance evaluation indexes includes bogie-vehicle coupled snaking motion stability, vehicle running smoothness and vehicle running safety performance.

[0012] In a second aspect, the application further provides a vehicle dynamics performance analysis system considering performance degradation of suspension parameters, including: A test module is configured to perform dynamic parameter testing on anti-snaking dampers and two types of high-speed bogie hydraulic dampers, i.e., secondary lateral dampers, on a hydraulic damper dynamic characteristic test bench to obtain dynamic characteristic data of the dampers under different running mileages and environmental temperature conditions; A fusion module is configured to fuse the dynamic characteristic data with a traditional Maxwell hydraulic damper model to establish a nonlinear Maxwell hydraulic damper model to simulate frequency variation and amplitude variation nonlinear characteristics of damper dynamic damping and stiffness; A first establishment module is configured to solve wheel-rail contact forces based on coupling of Hertz theory and Kalker simplified theory, and establish a vehicle system dynamics model in simulation software based on vehicle dynamics theory in combination with bogie components; A second establishment module is configured to integrate the nonlinear Maxwell hydraulic damper model into the vehicle system dynamics model to establish a vehicle system nonlinear dynamics model considering performance degradation of suspension parameters; The setting driving module is configured to set the nonlinear Maxwell hydraulic damper model parameters according to the obtained actual service mileage and the environment temperature of the vehicle, drive the vehicle system nonlinear dynamics model to perform dynamics simulation, and obtain simulation results. The analysis and evaluation module is configured to analyze the vehicle dynamics performance evaluation indexes based on the obtained simulation results, so as to complete the dynamics performance evaluation of the vehicle under the actual service mileage and the environment temperature conditions.

[0013] In a third aspect, the present application further provides a vehicle dynamics performance analysis device considering performance degradation of suspension parameters, comprising: The memory is configured to store the computer program. The processor is configured to implement the steps of the vehicle dynamics performance analysis method considering performance degradation of suspension parameters when the computer program is executed.

[0014] In a fourth aspect, the present application further provides a readable storage medium, wherein the readable storage medium stores a computer program, and the computer program is executed by a processor to implement the steps of the vehicle dynamics performance analysis method considering performance degradation of suspension parameters.

[0015] The present application has the following beneficial effects: The present application brings the dynamic characteristic test data of the hydraulic damper into the nonlinear force element, further integrates the data into the vehicle dynamics model, and can realize the reproduction of vehicle dynamics behavior and the analysis of performance evolution law under different operation mileages and environment temperature conditions. The present application can effectively reflect the influence of suspension parameter degradation on the vehicle dynamics performance, improves the precision of the track vehicle dynamics simulation model and the rationality of the analysis method, provides a method guidance for the vehicle dynamics analysis in a long-term service process, and has important theoretical research significance and engineering application value for the innovative design and intelligent operation and maintenance of the track vehicle.

[0016] Other features and advantages of the present application will be illustrated in the following description, and some will become apparent from the description, or will be understood by those skilled in the art through implementation of the embodiments of the present application. The purposes and other advantages of the present application can be achieved and obtained by the structures specifically indicated in the written description, claims, and drawings. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as limiting the scope. For those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

[0018] Figure 1Schematic diagram of the process flow of a vehicle dynamics performance analysis method considering suspension parameter performance degradation according to an embodiment of the present invention; Figure 2 Schematic diagram of the structure of a vehicle dynamics performance analysis system considering suspension parameter performance degradation according to an embodiment of the present invention; Figure 3 Schematic diagram of the structure of a vehicle dynamics performance analysis device taking into account suspension parameter performance degradation according to an embodiment of the present invention; Figure 4 A schematic diagram of a force-displacement hysteresis curve of a hydraulic shock absorber in a vehicle dynamics performance analysis method considering suspension parameter performance degradation according to an embodiment of the present invention; Figure 5 Schematic diagram of the hydraulic shock absorber spring-damper series force element model in the vehicle dynamics performance analysis method considering suspension parameter performance degradation described in an embodiment of the present invention, wherein: x represents the excitation displacement, f Indicates the shock absorber output force, c d represents the damping coefficient of the series damping unit, k d represents the stiffness coefficient of the series spring element, x d represents the displacement of the midpoint; Figure 6 The excitation displacement in the vehicle dynamics performance analysis method considering the suspension parameter performance degradation described in the embodiment of the present invention x , output force f and the model mid-node displacement x d Schematic diagram of time history signal.

[0019] In the figure: 701, test module; 702, fusion module; 703, first establishment module; 704, second establishment module; 705, setting drive module; 706, analysis and evaluation module; 800, vehicle dynamics performance analysis equipment considering suspension parameter performance degradation; 801, processor; 802, memory; 803, multimedia component; 804, I / O interface; 805, communication component. DETAILED DESCRIPTION

[0020] In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0021] It should be noted that similar reference numerals and letters represent similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. Meanwhile, in the description of the present application, the terms "first", "second", and the like are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0022] Embodiment 1

[0023] The embodiment provides a vehicle dynamics performance analysis method considering performance degradation of suspension parameters.

[0024] Referring to Figure 1 , the method includes steps S100, S200, S300, S400, S500 and S600.

[0025] S100, dynamic parameter testing is performed on two types of high-speed bogie hydraulic dampers, i.e., anti-snaking dampers and secondary lateral dampers, on a hydraulic damper dynamic characteristic test bench, to obtain dynamic characteristic data of the dampers under different running mileages and environmental temperature conditions; It can be understood that the step S100 includes the following steps: Step 11, anti-snaking, lateral and vertical hydraulic dampers with different service mileages are selected as test samples; Step 12, a simple harmonic excitation signal is applied in a displacement control mode on the hydraulic damper dynamic characteristic test bench, and a force feedback of an actuator is synchronously collected as a damper output force signal, wherein the simple harmonic excitation includes a sine wave with an input displacement amplitude and a frequency of the hydraulic actuator; Step 13, a force-displacement hysteresis curve is drawn according to the simple harmonic excitation signal and the damper output force signal, and equivalent stiffness and damping coefficients of the damper under the excitation state are calculated according to the force-displacement hysteresis curve; Step 14: Repeat step S13 to obtain the stiffness and damping under all frequency-amplitude combinations, and place the tested shock absorber in the environmental chamber for ≥ 24 hours. Then, change the test temperature and complete the corresponding test again. Replace the shock absorber with different mileages and repeat steps S12-S14 until a complete dynamic characteristics database is obtained under the new and various mileage conditions.

[0026] It should be noted that the hydraulic shock absorbers (anti-snaking shock absorbers, lateral shock absorbers, vertical shock absorbers) with different service mileages were selected as test specimens, such as shock absorbers in the newly manufactured state and those in the running state of 1.2 million km, 2.4 million km, and 4.8 million km. Then, the dynamic characteristics test of the tested shock absorbers was carried out using a hydraulic shock absorber dynamic characteristics test bench. The test bench adopts displacement control for loading, and the simple harmonic wave signal is input to the tested shock absorber through the hydraulic actuator of the test bench. The force signal fed back by the hydraulic actuator is recorded as the output force signal of the tested shock absorber. The simple harmonic excitation displacement amplitude is d 0 (unit: m), the excitation frequency is f (Unit: Hz).

[0027] Then, based on the simple harmonic displacement excitation signal and the shock absorber output force signal, a force-displacement hysteresis curve (also known as an indicator diagram) is drawn. Based on the hysteresis curve, the equivalent stiffness and damping coefficient of the shock absorber under the excitation state can be calculated; among them, the shock absorber force-displacement hysteresis curve is as follows Figure 4 As shown, the horizontal axis represents the shock absorber movement displacement, and the vertical axis represents the shock absorber output force

[0028] Among them, the force-displacement hysteresis curve of the hydraulic shock absorber F - x It is generally in the shape of a deflected ellipse because the output force lags behind the excitation displacement by a certain phase angle. φ , take the deflection ellipse and x The force at the intersection of the positive half axis of the axis (abscissa axis) is x 0, and the excitation displacement amplitude is set to d 0, then the phase angle of the shock absorber can be calculated; The calculation formula of the phase angle of the shock absorber in step 13 is as follows:

[0029] Where, φ is the phase angle of the shock absorber output force lagging behind the excitation displacement, x 0 is the force at the intersection of the deflected ellipse and the positive half axis of the x-axis, d 0 is the excitation displacement amplitude; The calculation formulas for the equivalent stiffness and damping coefficient in step 13 are as follows:

[0030] wherein, A c is the area enclosed by the force-displacement hysteresis curve, and ω is the excitation circular frequency, c d is the equivalent damping coefficient of the shock absorber under the excitation condition, k d is the equivalent stiffness coefficient of the shock absorber under the excitation condition, π is the ratio of the circumference to the diameter, φ is the phase angle of the output force of the shock absorber lagging behind the excitation displacement, d 0 is the amplitude of the excitation displacement.

[0031] Further, the frequency (0.5-15 Hz, step 0.5 Hz) and amplitude (0.25-3 mm, step 0.25 mm) of the displacement harmonic excitation signal are changed, and step S13 is repeated to obtain the equivalent stiffness and damping coefficient of the subject shock absorber under different excitation frequencies and displacement amplitudes, and the frequency-dependent and amplitude-dependent characteristics of the dynamic stiffness and damping coefficient are obtained.

[0032] In this step, the environmental test temperature is changed and the above steps are repeated to complete the dynamic characteristic test, wherein the subject shock absorber is placed in the environmental temperature chamber for more than 24 hours before the dynamic characteristic test is performed, and the environmental temperature is recommended to be -60°C-60°C with an interval of 10°C. Finally, different hydraulic shock absorbers with different service miles are replaced, and the above test steps are repeated to obtain the dynamic characteristic data of the hydraulic shock absorber in the new state and the state with certain service miles.

[0033] S200, the dynamic characteristic data is fused with the traditional Maxwell hydraulic shock absorber model to establish a nonlinear Maxwell hydraulic shock absorber model to simulate the frequency-dependent and amplitude-dependent nonlinear characteristics of the dynamic damping and stiffness of the shock absorber.

[0034] It can be understood that in this step S200, S201, S202, S203 and S204 are included, wherein: S201, the equivalent damping and equivalent stiffness corresponding to different excitation frequency-displacement amplitude combinations in the dynamic characteristic data are sorted out as modeling data; S202, the modeling data is substituted into the damping-spring series force element model to obtain a traditional Maxwell hydraulic shock absorber model; wherein, the traditional Maxwell hydraulic shock absorber model is composed of a damping unit and a spring unit in series, as shown in Figure 5 .

[0035] S203, based on the obtained measured data, a nonlinear force-displacement relationship curve is constructed by converting the phase difference φ, and a nonlinear force-velocity relationship curve is constructed by the velocity amplitude, so as to convert the traditional Maxwell hydraulic damper model into a nonlinear Maxwell force element model, so as to match the dynamic working condition of the changing frequency amplitude of the vehicle operation excitation; S204, embedding the obtained nonlinear force-displacement relationship curve and nonlinear force-velocity relationship curve into the Maxwell model and carrying out numerical simulation, reproducing the damper frequency amplitude coupling characteristics, and calling the frequency or amplitude results as needed, completing the nonlinear characteristic simulation of the frequency and amplitude variation of the damper dynamic parameters.

[0036] It should be noted that the above hydraulic damper dynamic characteristic data is specifically the damper equivalent damping and stiffness values under different excitation frequencies and displacement amplitudes.

[0037] The equivalent damping and stiffness values measured under the above specific excitation frequency and displacement amplitude working condition are respectively substituted into the damping-spring series force element model, and the establishment of the traditional Maxwell hydraulic damper model is completed. Among them, the excitation displacement of the Maxwell model x , the intermediate node displacement x d and the output force F Time history signal and phase angle φ are shown in Figure 6 .

[0038] The above step of the traditional spring-damping series Maxwell model generally uses fixed stiffness and damping coefficient as the model input to simulate the dynamic response under a specific excitation frequency and amplitude condition. However, the vibration excitation of the vehicle in the dynamic running process is dynamically changing, therefore, it is necessary to further construct a nonlinear Maxwell force element model, that is, to replace the fixed stiffness with a nonlinear force-displacement relationship curve and replace the fixed damping with a nonlinear force-velocity relationship curve, and these nonlinear relationship curves are obtained according to the suspension element dynamic characteristic test data.

[0039] Further, in order to obtain the nonlinear Maxwell force element model parameters, it is known that the harmonic excitation displacement amplitude of the damper is d 0 and the frequency is f , then the maximum equivalent excitation velocity is , then the maximum movement velocity of the series damping unit is . Assuming that the equivalent damping coefficient of the damper is c d , then the output force of the Maxwell model series damping unit is . For a certain excitation displacement d 0 working condition, by changing the excitation frequency fThe output force of the damping unit under different excitation frequencies can be obtained and the motion speed . Thus, the nonlinear force-velocity characteristic curve of the damping force unit is obtained.

[0040] Further, since there is a phase difference φ between the displacement of the spring unit and the displacement of the harmonic displacement excitation, the maximum deformation of the spring unit can be calculated Since the spring unit and the damping unit in the Maxwell model are in series, the forces of the two units are the same, i.e. , wherein represents the maximum output force of the spring unit. Thus, the nonlinear force-displacement relationship curve of the spring unit is obtained.

[0041] The nonlinear force-velocity and force-displacement relationship curves in the above steps are obtained by post-processing of dynamic characteristic test data, and each data point in the curve corresponds to a certain excitation frequency condition. The dynamic characteristic test is performed under a certain displacement amplitude harmonic excitation condition, and the test frequency is set to 0.5 Hz and 1-12 Hz (step size 1 Hz).

[0042] Using the obtained nonlinear force-velocity relationship curve and nonlinear force-displacement relationship curve, the Maxwell model is brought into numerical simulation, the output force under the condition of harmonic displacement excitation is calculated, and the dynamic characteristic curve under different excitation frequencies is obtained according to the dynamic stiffness and damping coefficient calculation method, realizing the frequency-dependent characteristic simulation of the dynamic parameters of the shock absorber based on the measured dynamic characteristic data. Similar to the above steps, by fixing the harmonic excitation frequency of the test and changing the harmonic displacement excitation amplitude, the amplitude-dependent characteristic simulation of the dynamic parameters of the shock absorber can be obtained.

[0043] According to the vehicle dynamics simulation analysis conditions mentioned later, the dynamic parameter frequency-dependent characteristics (a certain excitation displacement condition) or the amplitude-dependent characteristics of the dynamic parameters (a certain excitation frequency condition) are selected and brought into the vehicle dynamics model to complete the simulation of the nonlinear characteristics of the suspension elements and the simulation analysis of the vehicle dynamics performance.

[0044] S300, based on the coupling solution of Hertz theory and Kalker simplified theory, and combined with the bogie components, a vehicle system dynamics model is established in the simulation software based on vehicle dynamics theory.

[0045] It can be understood that the step S300 includes S301, S302 and S303. S301, input the LM type worn tread and the 60 kg / m rail profile through the wheel-rail contact geometry module to generate the wheel-rail contact geometry, calculate the wheel-rail normal force and the contact ellipse major and minor axes by using the Hertz theory, input the wheel-rail normal force and the contact ellipse major and minor axes into the Kalker simplified theory to solve the longitudinal, lateral and spin creep forces in real time, and thus establish a wheelset system dynamics submodel; S302, take the wheelset as the core, integrate the steel spring, air spring, rubber node and hydraulic damper according to the “rotating arm-axle box-frame-secondary suspension-car body” hierarchical topology, and build a whole vehicle multi-body dynamics topology; S303, based on the whole vehicle multi-body dynamics topology, configure the variable step size implicit integrator parameters, simulation time length 30 s and sampling frequency 1000 Hz in the DAP-Rail solver setting module, load the German high interference track spectrum as the track excitation, perform initialization and static balance solving, and thus complete the establishment of the vehicle system dynamics model.

[0046] It should be noted that the wheel-rail relationship is established in the DAP-Rail software, including the wheel-rail contact geometry relationship and the rolling contact relationship; wherein the rolling contact mainly solves the wheel-rail normal force and the creep force by using the Hertz contact theory and the Kalker simplified theory; and based on the above wheel-rail relationship, a wheelset system dynamics submodel is established; further based on the wheelset system submodel, rigid bodies such as axle box rotating arm, frame and car body are added, and further one and two suspension components such as steel spring, air spring, rubber node and hydraulic damper are added; finally, the integrator parameters and the calculation time length are set in the solver setting module of the DAP-Rail software, and thus the establishment of the traditional vehicle system dynamics model is completed.

[0047] S400, integrate the nonlinear Maxwell hydraulic damper model into the vehicle system dynamics model to establish a vehicle system nonlinear dynamics model considering the performance degradation of the suspension parameters.

[0048] It can be understood that in this step S400, S401, S402 and S403 are included. S401, based on the vehicle system dynamics model, call the Maxwell type hydraulic damper force element template of DAP-Rail, replace the fixed stiffness term and the fixed damping term in the force element parameter list with the nonlinear force-displacement relationship curve and the nonlinear force-velocity relationship curve respectively, to generate a single damper nonlinear Maxwell force element; S402. Map nonlinear Maxwell force elements in batches to hydraulic shock absorbers in various parts of the vehicle, including at least anti-snaking shock absorbers, lateral shock absorbers, and vertical shock absorbers. Degradation curve data corresponding to service mileage and ambient temperature is imported. The Maxwell parameters of all suspension damping components of the vehicle are replaced with nonlinear stiffness and damping parameters, thereby forming a nonlinear dynamic model of the vehicle system at the topological level that takes into account suspension parameter performance degradation. S403. Set the variable-step implicit integrator parameters, simulation duration, and sampling frequency in the DAP-Rail solver setup module, load the track irregularity excitation, and perform initialization and static balance solutions to activate and calibrate the topological layer to form a nonlinear dynamic model of the vehicle system that takes into account suspension parameter performance degradation. This generates a nonlinear dynamic model of the vehicle system that takes into account suspension parameter performance degradation for dynamic performance evaluation.

[0049] It should be noted that, referring to the above steps, the Maxwell model parameters corresponding to the hydraulic shock absorbers at different parts of the vehicle (such as anti-snaking shock absorbers, lateral shock absorbers, vertical shock absorbers, etc.) are replaced with nonlinear stiffness and damping parameters to establish a nonlinear dynamic model of the vehicle system that takes into account the performance degradation of suspension parameters.

[0050] S500 , according to the obtained actual service mileage and ambient temperature of the vehicle, set the nonlinear Maxwell hydraulic shock absorber model parameters, and drive the nonlinear dynamic model of the vehicle system to perform dynamic simulation to obtain simulation results.

[0051] It can be understood that step S500 includes S501, S502 and S503, wherein: S501. In the nonlinear dynamics model of the vehicle system, locate the Maxwell force elements corresponding to all anti-snaking shock absorbers, and bind the obtained vehicle actual service mileage and ambient temperature input ports to the external parameter table interface to form a call channel for subsequent mileage-temperature interpolation. S502, based on the mileage to be simulated x , extracted from the measured database x The closest two sets of mileage x 1 and x 2 and its corresponding force-displacement characteristic curves are f k1 and f k2 , obtain mileage by linear interpolation x The benchmark curve under the same mileage data subset is selected with the target ambient temperature t as the interpolation point, and the two closest temperature groups are selected. t 1. t 2 and its corresponding curve f’ k1 andf’ k2 and f’ d1 and f’ d2 , the temperature interpolation is completed, so as to obtain the force-displacement curve and the force-velocity curve coupled with the mileage-temperature; S503, the force-displacement curve and the force-velocity curve are input into the nonlinear parameter table of the anti-snake damper Maxwell force element, the parameter setting is completed, and then the DAP-Rail numerical integration module is started, the vehicle system dynamics equation is solved, the displacement-velocity time history of the wheel set, the frame and the vehicle body is output, and the wheel-rail vertical force and lateral force time history signals of all wheels are generated, so as to realize the vehicle dynamics performance simulation under the working condition, and obtain the simulation result.

[0052] It should be noted that the vehicle system dynamics model considering the performance degradation of the suspension parameters is established by using the above method, the corresponding nonlinear Maxwell force element model of the anti-snake damper, the lateral damper and the vertical damper is selected in the DAP-Rail suspension force element module; according to the dynamic characteristic data (force-displacement characteristic curve and force-velocity characteristic curve) of the damper under different running mileage conditions obtained by the above steps, the dynamic characteristic data under the running mileage to be simulated is selected according to the running mileage to be simulated, and the dynamic characteristic data under the running mileage to be simulated is obtained according to the linear interpolation method.

[0053] Suppose the running mileage to be simulated is x , the two groups of running mileage measured on the test bench closest to the running mileage to be simulated are x 1 and x 2, and the corresponding force-displacement characteristic curves are f k1 and f k2 , the corresponding force-velocity characteristic curves are f d1 and f d2 . According to the mileage, the above dynamic characteristic data is linearly interpolated to obtain the force-displacement characteristic curve x f k and the force-velocity characteristic curve f d corresponding to the mileage

[0054] According to the above steps, the mileage closest to the simulated mileage x ​the test data as the interpolation data set of the environment temperature data to be analyzed, i.e. the force-displacement characteristic curve and the force-velocity characteristic curve under different environment temperature conditions at the selected mileage; According to the selected dynamic characteristic data set of the shock absorber at a specific mileage, the dynamic characteristic data set of the shock absorber at the environment temperature t to be analyzed is obtained according to the selected dynamic characteristic data set of the shock absorber at a specific mileage, the dynamic characteristic data set of the shock absorber at the environment temperature t to be analyzed is obtained according to the selected dynamic characteristic data set of the shock absorber at a specific mileage, the dynamic characteristic data set of the shock absorber at the environment temperature t 1 and t 2 closest to the environment temperature f’ k1 and f’ k2 , and the corresponding force-velocity characteristic curves are f’ d1 and f’ d2 . According to the environment temperature, the above dynamic characteristic data is linearly interpolated to obtain the corresponding force-displacement characteristic curve f’ k and the force-velocity characteristic curve f’ d at the environment temperature t :

[0055] According to the force-displacement characteristic curve f’ k and the force-velocity characteristic curve f’ d obtained in the above steps, the stiffness and damping parameters of the hydraulic shock absorber in the vehicle system nonlinear dynamics model in the DAP-Rail software are set, and the nonlinear parameter setting of the shock absorber is completed; Further, the DAP-Rail software numerical integration module is used to solve the vehicle dynamics equation, realize the vehicle dynamics performance simulation under the working condition, and obtain the time history signals of the wheel-rail vertical force and lateral force of all wheels.

[0056] Among them, the dynamics simulation mainly refers to solving the vehicle system dynamics equation, obtaining the displacement and velocity signals of the wheel set, bogie and car body motion degrees of freedom, and outputting the wheel-rail system force, suspension system force and other signals.

[0057]

[0058] In the formula, M represents the mass matrix of the vehicle system, C represents the system damping matrix, K represents the system stiffness matrix, Y represents the system motion displacement degree of freedom vector, and and represent the velocity and acceleration vectors respectively; F wr represents the wheel-rail system force vector, including the vertical force, lateral force and longitudinal force of all wheels; F Srepresents the force vector of the suspension system (excluding the hydraulic shock absorber); F d represents the output force vector of the hydraulic shock absorber.

[0059] S600, based on the obtained simulation results, analyzing the vehicle dynamics performance evaluation index to complete the dynamics performance evaluation of the vehicle under the actual service mileage and environmental temperature conditions.

[0060] It can be understood that in this step S600, S601, S602 and S603 are included, wherein: According to the wheel-rail vertical force and lateral force time history signals of all wheels, the vehicle dynamics performance evaluation index is calculated and obtained, and a quantitative performance database under the working condition is formed; The quantitative performance database is compared with the existing specification, the indexes exceeding the threshold or close to the limit value are identified, and the corresponding mileage-temperature working condition is traced back, so as to determine the potential dynamics risk points of the vehicle under the actual service mileage and environmental temperature conditions; Using the identified potential dynamics risk points, maintenance or replacement suggestions for different service stages are generated, and the dynamics performance evaluation of the vehicle under the actual service mileage and environmental temperature conditions is completed.

[0061] It should be noted that the wheel-rail force signals obtained according to the above steps are used for vehicle dynamics performance evaluation according to GB / T 5599-2019; the main evaluation contents include snake movement stability (judged by frame lateral acceleration), running smoothness (judged by smoothness index and comfort index) and running safety performance (judged by derailment coefficient, wheel load reduction rate and wheel axle lateral force index), so as to set different running mileage and environmental temperature analysis working conditions, repeat the above steps, and then the vehicle dynamics performance under different running mileage and environmental temperature working conditions can be obtained, so as to complete the dynamics performance prediction and evaluation under the actual service working condition.

[0062] Embodiment 2:

[0063] As shown in Figure 2 The embodiment provides a vehicle dynamics performance analysis system considering suspension parameter performance degradation, as shown in Figure 2 The system comprises: The test module 701 is used for testing the dynamic parameters of the anti-snake shock absorber and the two types of high-speed bogie hydraulic shock absorbers on the hydraulic shock absorber dynamic characteristic test bench, and obtaining the dynamic characteristic data under different running mileage and environmental temperature conditions; The fusion module 702 is used for fusing the dynamic characteristic data with the traditional Maxwell hydraulic shock absorber model, establishing a nonlinear Maxwell hydraulic shock absorber model, and simulating the frequency variation and amplitude variation nonlinear characteristics of the dynamic damping and stiffness of the shock absorber; The first establishing module 703 is configured to establish a vehicle system dynamics model based on a wheel-rail contact force solved by coupling Hertz theory and Kalker's simplified theory and in combination with a bogie component in a simulation software based on vehicle dynamics theory. The second establishing module 704 is configured to integrate a nonlinear Maxwell hydraulic damper model into the vehicle system dynamics model to establish a vehicle system nonlinear dynamics model considering performance degradation of suspension parameters. The setting driving module 705 is configured to set parameters of the nonlinear Maxwell hydraulic damper model according to the obtained actual service mileage and environmental temperature of the vehicle, and drive the vehicle system nonlinear dynamics model to perform dynamics simulation to obtain simulation results. The analysis and evaluation module 706 is configured to analyze a vehicle dynamics performance evaluation index based on the obtained simulation results to complete dynamics performance evaluation of the vehicle under the actual service mileage and environmental temperature conditions.

[0064] It should be noted that, as to the system in the above embodiment, the specific manner in which each module performs operations has been described in detail in the embodiment of the method, and will not be described in detail here.

[0065] Embodiment 3

[0066] Corresponding to the above method embodiment, the embodiment also provides a vehicle dynamics performance analysis device considering performance degradation of suspension parameters. The vehicle dynamics performance analysis device considering performance degradation of suspension parameters described below can be mutually corresponding to the vehicle dynamics performance analysis method considering performance degradation of suspension parameters described above.

[0067] Figure 3 Fig. 8 is a block diagram of a vehicle dynamics performance analysis device 800 considering performance degradation of suspension parameters according to an example embodiment. As shown in the figure, the vehicle dynamics performance analysis device 800 considering performance degradation of suspension parameters includes a processor 801 and a memory 802. The vehicle dynamics performance analysis device 800 considering performance degradation of suspension parameters also includes one or more of a multimedia component 803, an I / O interface 804, and a communication component 805. Figure 3

[0068] ​The processor 801 is configured to control overall operation of the vehicle dynamics performance analysis device 800 considering suspension parameter performance degradation, to accomplish all or part of the steps of the vehicle dynamics performance analysis method considering suspension parameter performance degradation described above. The memory 802 is configured to store various types of data to support operation of the vehicle dynamics performance analysis device 800 considering suspension parameter performance degradation, which can include, for example, instructions for any application or method operating on the vehicle dynamics performance analysis device 800 considering suspension parameter performance degradation, and application-related data, such as contact data, sent and received messages, pictures, audio, video, and the like. The memory 802 can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as Static Random Access Memory (SRAM), Electrically Erasable Programmable Read-Only Memory (EEPROM), Erasable Programmable Read-Only Memory (EPROM), Programmable Read-Only Memory (PROM), Read-Only Memory (ROM), magnetic storage, flash memory, magnetic or optical disk. The multimedia component 803 can include a screen and an audio component. The screen can be, for example, a touch screen, and the audio component is configured to output and / or input audio signals. For example, the audio component can include a microphone configured to receive external audio signals. The received audio signals can be further stored in the memory 802 or transmitted through the communication component 805. The audio component also includes at least one speaker configured to output audio signals. The I / O interface 804 provides an interface between the processor 801 and other interface modules, which can be a keyboard, a mouse, or a button, and the like. The buttons can be virtual buttons or physical buttons. The communication component 805 is configured to enable wired or wireless communication between the vehicle dynamics performance analysis device 800 considering suspension parameter performance degradation and other devices. Wireless communication, such as Wi-Fi, Bluetooth, Near Field Communication (NFC), 2G, 3G, or 4G, or a combination of one or more of them, so the corresponding communication component 805 can include a Wi-Fi module, a Bluetooth module, or an NFC module.

[0069] In an example embodiment, the vehicle dynamics performance analysis device 800 considering suspension parameter performance degradation can be implemented by one or more Application Specific Integrated Circuits (ASICs), Digital Signal Processors (DSPs), Digital Signal Processing Devices (DSPDs), Programmable Logic Devices (PLDs), Field Programmable Gate Arrays (FPGAs), controllers, microcontrollers, microprocessors or other electronic elements for performing the above-mentioned vehicle dynamics performance analysis method considering suspension parameter performance degradation.

[0070] In another example embodiment, a computer readable storage medium including program instructions is also provided, which when executed by a processor, implement the steps of the above-mentioned vehicle dynamics performance analysis method considering suspension parameter performance degradation. For example, the computer readable storage medium can be the above-mentioned memory 802 including program instructions, which can be executed by the processor 801 of the vehicle dynamics performance analysis device 800 considering suspension parameter performance degradation to complete the above-mentioned vehicle dynamics performance analysis method considering suspension parameter performance degradation.

[0071] Embodiment 4:

[0072] Corresponding to the above method embodiments, in this embodiment, a readable storage medium is also provided, which can be referred to in conjunction with the above-mentioned vehicle dynamics performance analysis method considering suspension parameter performance degradation.

[0073] The computer program stored on the readable storage medium, when executed by a processor, implements the steps of the above-mentioned vehicle dynamics performance analysis method considering suspension parameter performance degradation of the method embodiments.

[0074] The readable storage medium can be specifically a U disk, a mobile hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and various readable storage media that can store program codes.

[0075] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

[0076] 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 or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A vehicle dynamics performance analysis method considering suspension parameter performance degradation, characterized in that: include: On the hydraulic shock absorber dynamic characteristics test bench, dynamic parameter tests were conducted on two types of high-speed bogie hydraulic shock absorbers: anti-snaking shock absorbers and secondary lateral shock absorbers, to obtain their dynamic characteristics data under different mileage and ambient temperature conditions; The dynamic characteristic data is integrated with the traditional Maxwell hydraulic shock absorber model to establish a nonlinear Maxwell hydraulic shock absorber model to simulate the frequency-dependent and amplitude-dependent nonlinear characteristics of the shock absorber's dynamic damping and stiffness. The wheel-rail contact force is solved based on the coupling of Hertz theory and Kalk simplified theory, and the vehicle system dynamics model is established in the simulation software based on vehicle dynamics theory in combination with the bogie components. The nonlinear Maxwell hydraulic shock absorber model is integrated into the vehicle system dynamics model to establish a nonlinear dynamics model of the vehicle system that takes into account the performance degradation of suspension parameters. According to the actual service mileage and ambient temperature of the vehicle, the parameters of the nonlinear Maxwell hydraulic shock absorber model are set, and the nonlinear dynamic model of the vehicle system is driven to perform dynamic simulation to obtain simulation results; Based on the obtained simulation results, the vehicle dynamics performance evaluation indicators are analyzed to complete the vehicle dynamics performance evaluation under actual service mileage and ambient temperature conditions.

2. The vehicle dynamics performance analysis method considering suspension parameter performance degradation according to claim 1, characterized in that: On the hydraulic shock absorber dynamic characteristics test bench, dynamic parameter tests were conducted on two types of high-speed bogie hydraulic shock absorbers, the anti-snaking shock absorber and the secondary lateral shock absorber, to obtain their dynamic characteristic data under different mileage and ambient temperature conditions, including: Step 11: Select anti-snaking shock absorbers and secondary lateral shock absorbers with different service mileages as test pieces; Step 12: On a hydraulic shock absorber dynamic characteristics test bench, a simple harmonic excitation signal is applied in a displacement control manner, and the force feedback from the actuator is simultaneously collected as the shock absorber output force signal, wherein the simple harmonic excitation includes a sine wave of displacement amplitude and frequency input by the hydraulic actuator; Step 13: Draw a force-displacement hysteresis curve based on the simple harmonic excitation signal and the shock absorber output force signal, and calculate the equivalent stiffness and damping coefficient of the shock absorber under the excitation state based on the force-displacement hysteresis curve; Step 14: Repeat step S13 to obtain the stiffness and damping under all frequency-amplitude combinations, and place the tested shock absorber in the environmental chamber for ≥ 24 hours. Then, change the test temperature and complete the corresponding test again. Replace the shock absorber with different mileages and repeat steps S12-S14 until a complete dynamic characteristics database is obtained under the new and various mileage conditions.

3. The vehicle dynamics performance analysis method considering suspension parameter performance degradation according to claim 2, characterized in that: The equivalent stiffness and damping coefficient of the shock absorber under the excitation state are calculated based on the force-displacement hysteresis curve. The calculation formulas of the equivalent stiffness and damping coefficient are as follows: Where, φ is the phase angle of the shock absorber output force lagging behind the excitation displacement, x 0 is the force at the intersection of the deflected ellipse and the positive half axis of the x-axis, d 0 is the excitation displacement amplitude; Based on the phase angle, the equivalent damping and stiffness coefficients of the shock absorber are calculated using the following formula: Where, A c is the area enclosed by the force-displacement hysteresis curve, ω is the excitation frequency, c d is the equivalent damping coefficient of the shock absorber under this excitation condition, k d is the equivalent stiffness coefficient of the shock absorber under this excitation condition, π is pi, φ is the phase angle of the shock absorber output force lagging behind the excitation displacement, d 0 is the excitation displacement amplitude.

4. The vehicle dynamics performance analysis method considering suspension parameter performance degradation according to claim 1, characterized in that: The dynamic characteristic data is integrated with the traditional Maxwell hydraulic shock absorber model to establish a nonlinear Maxwell hydraulic shock absorber model to simulate the frequency-dependent and amplitude-dependent nonlinear characteristics of the shock absorber's dynamic damping and stiffness, including: Arrange the equivalent damping and equivalent stiffness corresponding to different excitation frequency-displacement amplitude combinations in the dynamic characteristics data as modeling data; Substituting the modeling data into the damper-spring series force element model, the traditional Maxwell hydraulic shock absorber model is obtained; Based on the measured data, a nonlinear force-displacement curve is constructed using the maximum spring deformation converted from the phase difference φ, and a nonlinear force-velocity curve is constructed using the velocity amplitude. This converts the traditional Maxwell hydraulic shock absorber model into a nonlinear Maxwell force element model to match the dynamic operating conditions of the vehicle, where the excitation frequency and amplitude continuously change. The obtained nonlinear force-displacement relationship curve and nonlinear force-velocity relationship curve are embedded in the Maxwell model and numerical simulation is carried out to reproduce the frequency-amplitude coupling characteristics of the shock absorber. The frequency or amplitude variation results are called as needed to complete the nonlinear characteristic simulation of the frequency and amplitude variation of the dynamic parameters of the shock absorber.

5. The vehicle dynamics performance analysis method considering suspension parameter performance degradation according to claim 1, characterized in that: The wheel-rail contact force is solved by coupling the Hertz theory with the Kalk simplified theory, and combined with the bogie components, a vehicle system dynamics model is established in the simulation software based on the vehicle dynamics theory, including: The wheel-rail contact geometry module generates the wheel-rail contact geometry by inputting the LM-type wear tread and the 60 kg / m rail profile. Hertz theory is used to calculate the wheel-rail normal force and the major and minor semi-axes of the contact ellipse. These are then input into the Kalk simplified theory to solve for the longitudinal, lateral, and spin creep forces in real time, thereby establishing a wheelset system dynamics sub-model. With the wheelset as the core, the system builds a multi-body dynamics topology based on the hierarchical topology of "axle box swing arm - primary suspension - frame - secondary suspension - body", integrating steel springs, air springs, rubber joints, and hydraulic shock absorbers. Based on the vehicle's multibody dynamics topology, the DAP-Rail solver settings module configures the variable-step implicit integrator parameters, a 30-second simulation duration, and a 1000-Hz sampling frequency. The German high-interference track spectrum is loaded as track excitation, and initialization and static equilibrium solutions are performed to complete the vehicle system dynamics model.

6. The vehicle dynamics performance analysis method considering suspension parameter performance degradation according to claim 1, characterized in that: The nonlinear Maxwell hydraulic shock absorber model is integrated into the vehicle system dynamics model to establish a nonlinear dynamics model of the vehicle system that takes into account the performance degradation of suspension parameters, including: Based on the vehicle system dynamics model, the Maxwell-type hydraulic shock absorber force element template from DAP-Rail was used. The fixed stiffness term and fixed damping term in the force element parameter list were replaced with nonlinear force-displacement curves and nonlinear force-velocity curves, respectively, to generate a nonlinear Maxwell force element for a single shock absorber. Nonlinear Maxwell force elements are batch-mapped to hydraulic shock absorbers in various parts of the vehicle, including at least the anti-snaking shock absorbers and secondary lateral shock absorbers. Degradation curve data corresponding to service mileage and ambient temperature is imported, and the Maxwell parameters of all suspension damping elements in the vehicle are replaced with nonlinear stiffness and damping parameters. This creates a nonlinear dynamic model of the vehicle system at the topological level that takes into account the performance degradation of suspension parameters. In the DAP-Rail solver setup module, the variable-step implicit integrator parameters, simulation duration, and sampling frequency are set. Track irregularity excitation is applied, and initialization and static equilibrium solutions are performed. This activates and calibrates the topologically generated nonlinear dynamic model of the vehicle system that takes into account suspension parameter performance degradation. This model is then generated for dynamic performance evaluation.

7. The vehicle dynamics performance analysis method considering suspension parameter performance degradation according to claim 1, characterized in that: The nonlinear Maxwell hydraulic shock absorber model parameters are set based on the actual service mileage and ambient temperature of the vehicle, and the nonlinear dynamic model of the vehicle system is driven to perform dynamic simulation to obtain simulation results, including: In the nonlinear dynamics model of the vehicle system, the Maxwell force elements corresponding to all anti-snaking dampers are located. The obtained actual vehicle mileage and ambient temperature input ports are bound to the external parameter table interface to form a call channel for subsequent mileage-temperature interpolation. Based on the mileage to be simulated being x, extract the two mileages closest to x from the measured database x 1 and x 2 and its corresponding force-displacement characteristic curves are f k1 and f k2 , obtain the reference curve under mileage x by linear interpolation; and in the same mileage data subset, use the target ambient temperature t as the interpolation point, select the two closest sets of temperatures t1, t2 and their corresponding curves f’ k1 and f’ k2 The corresponding force-velocity characteristic curves are f’ d1 and f’ d2 , complete the temperature interpolation, and thus obtain the mileage-temperature coupled force-displacement curve and force-velocity curve; The force-displacement and force-velocity curves were input into the nonlinear parameter table of the Maxwell force element of the anti-snaking damper to complete the parameter setting. The DAP-Rail numerical integration module was then activated to solve the vehicle system dynamics equations. The displacement-velocity time history of the wheelset, frame, and vehicle body was output, and the wheel-rail vertical force and lateral force time history signals for all wheels were generated to simulate the vehicle dynamics performance under this working condition and obtain the simulation results.

8. The vehicle dynamics performance analysis method considering suspension parameter performance degradation according to claim 7, characterized in that: Based on the obtained simulation results, the vehicle dynamics performance evaluation indicators are analyzed to complete the vehicle dynamics performance evaluation under actual service mileage and ambient temperature conditions, including: Based on the time history signals of the wheel / rail vertical and lateral forces of all wheels, the vehicle dynamics performance evaluation index is calculated to form a quantitative performance database under the working condition; Compare the quantitative performance database with current specifications to identify indicators that exceed thresholds or approach limits, and trace them back to corresponding mileage-temperature conditions to determine potential dynamic risk points under actual service mileage and ambient temperature conditions; By using the identified potential dynamic risk points, maintenance or replacement recommendations for different service stages are generated, thereby completing the vehicle's dynamic performance evaluation under actual service mileage and ambient temperature conditions.

9. The vehicle dynamics performance analysis method considering suspension parameter performance degradation according to claim 8, characterized in that: The analysis of vehicle dynamics performance evaluation indicators includes bogie-body coupled snaking motion stability, vehicle running smoothness and vehicle running safety performance.

10. A vehicle dynamics performance analysis system considering suspension parameter performance degradation, based on the vehicle dynamics performance analysis method considering suspension parameter performance degradation according to claim 1, characterized in that: include: Test module: Used to conduct dynamic parameter tests on two types of high-speed bogie hydraulic shock absorbers, anti-snaking shock absorbers and secondary lateral shock absorbers, on a hydraulic shock absorber dynamic characteristics test bench to obtain their dynamic characteristics data under different mileage and ambient temperature conditions; Fusion module: used to fuse dynamic characteristic data with the traditional Maxwell hydraulic shock absorber model to establish a nonlinear Maxwell hydraulic shock absorber model to simulate the frequency-varying and amplitude-varying nonlinear characteristics of the shock absorber's dynamic damping and stiffness; The first building module is used to solve the wheel-rail contact force based on the coupling of Hertz theory and Kalk simplified theory, and to establish a vehicle system dynamics model in simulation software based on vehicle dynamics theory in combination with bogie components; The second building module is used to integrate the nonlinear Maxwell hydraulic shock absorber model into the vehicle system dynamics model to establish a nonlinear dynamics model of the vehicle system that takes into account the performance degradation of suspension parameters; Setting drive module: used to set the parameters of the nonlinear Maxwell hydraulic shock absorber model according to the actual service mileage and ambient temperature of the vehicle, and drive the nonlinear dynamic model of the vehicle system to perform dynamic simulation and obtain simulation results; Analysis and evaluation module: used to analyze vehicle dynamics performance evaluation indicators based on the obtained simulation results, so as to complete the vehicle's dynamic performance evaluation under actual service mileage and ambient temperature conditions.

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