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

Abstract

The application provides a vehicle dynamics performance analysis method and system considering suspension parameter performance degradation, relates to the technical field of railway vehicle dynamics, and comprises the following steps: a nonlinear Maxwell hydraulic damper model is established; a vehicle system dynamics model is established in simulation software based on vehicle dynamics theory; the nonlinear Maxwell hydraulic damper model is integrated into the vehicle system dynamics model to establish a vehicle system nonlinear dynamics model considering suspension parameter performance degradation; parameters of the nonlinear Maxwell hydraulic damper model are set to obtain simulation results; and vehicle dynamics performance evaluation indexes are analyzed to complete the dynamics performance evaluation of the vehicle under actual service mileage and environmental temperature conditions. The application effectively reflects the influence of suspension parameter degradation on vehicle dynamics performance, improves the precision of the simulation model of the railway vehicle dynamics and the rationality of the 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 load bearing, guiding, vibration reduction 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 vibration reduction. The suspension system of the motor train unit bogie 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, shock absorbers and limit stops, such as steel springs, air springs, elastic rubber parts, oil hydraulic shock absorbers and rubber stops. Among them, the hydraulic shock absorber is an important suspension element, including anti-yaw shock absorber, secondary lateral shock absorber and vertical shock absorber, 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 shock absorber, the hardening and softening of the rubber element, etc., which 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:

[0005] In the first aspect, the present application provides a vehicle dynamics performance analysis method considering performance degradation of suspension parameters, comprising:

[0006] On the hydraulic shock absorber dynamic characteristic test bench, dynamic parameter testing is performed on two types of high-speed bogie hydraulic shock absorbers, namely anti-yaw shock absorber and secondary lateral shock absorber, to obtain their dynamic characteristic data under different running mileage and environmental temperature conditions;

[0007] 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 variation and amplitude variation nonlinear characteristics of the dynamic damping and stiffness of the shock absorber;

[0008] Based on the coupling of Hertz theory and Kalker simplified theory to solve wheel-rail contact force, and combined with the bogie components, a vehicle system dynamics model is established in the simulation software based on the vehicle dynamics theory;

[0009] 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 suspension parameters;

[0010] According to the obtained actual service mileage and environmental temperature of the vehicle, the nonlinear Maxwell hydraulic damper model parameters are set, and the vehicle system nonlinear dynamics model is driven to perform dynamics simulation to obtain simulation results;

[0011] 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.

[0012] Preferably, the dynamic parameter test of the anti-snaking damper and the secondary lateral damper of the high-speed bogie hydraulic damper is carried out on the hydraulic damper dynamic characteristic test bench, and the dynamic characteristic data of the hydraulic damper under different operating mileages and environmental temperature conditions are obtained, which include:

[0013] Step 11, selecting anti-snaking, secondary lateral and vertical hydraulic dampers with different service mileages as test samples;

[0014] Step 12, on the hydraulic damper dynamic characteristic test bench, a harmonic excitation signal is applied in a displacement control mode, and the force feedback of the actuator is synchronously collected 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;

[0015] Step 13, according to the harmonic excitation signal and the damper output force signal, a force-displacement hysteresis curve is drawn, and the equivalent stiffness and damping coefficient of the damper under the excitation state are calculated according to the force-displacement hysteresis curve;

[0016] Step 14, repeat step S13 to obtain the stiffness and damping under all frequency-amplitude combinations, and place the test damper in the environmental chamber for ≥24 h, then change the test temperature, repeat the corresponding test, replace the damper with different operating mileages, repeat steps S12-S14 until the complete dynamic characteristic database under the new and each service mileage state is obtained.

[0017] 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, which includes:

[0018] 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;

[0019] The modeling data is substituted into a damping-spring series force element model to obtain a traditional Maxwell hydraulic damper model;

[0020] Based on the obtained measured data, a spring maximum deformation converted by a phase difference φ is used to construct a nonlinear force-displacement relationship curve, and a velocity amplitude is used to construct a 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 continuously changing excitation frequency and amplitude during vehicle operation;

[0021] 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-variable or amplitude-variable results are called as needed to complete the nonlinear characteristic simulation of the damper dynamic parameters.

[0022] Preferably, the wheel-rail contact force is solved based on the coupling of the Hertz theory and the Kalker simplified theory, and a vehicle system dynamics model is established in a simulation software based on vehicle dynamics theory, which includes:

[0023] The LM type worn tread and the 60 kg / m rail profile are input through a wheel-rail contact geometry module to generate wheel-rail contact geometry, the Hertz theory is used to calculate the wheel-rail normal force and the contact ellipse major and minor axes, 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, so as to establish a wheelset system dynamics submodel;

[0024] Taking the wheelset as the core, a "rotating arm-axle box-frame-secondary suspension-car body" hierarchical topology is used to integrate steel springs, air springs, rubber nodes and hydraulic dampers to construct a whole vehicle multi-body dynamics topology;

[0025] Based on the whole vehicle multi-body dynamics topology, the variable step implicit integrator parameters, the simulation time length 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.

[0026] 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:

[0027] 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 respectively replaced by the nonlinear force-displacement relationship curve and the nonlinear force-velocity relationship curve to generate a single damper nonlinear Maxwell force element;

[0028] The nonlinear Maxwell force element is batch mapped to the hydraulic damper of each part of the vehicle, at least including the anti-snaking damper, the lateral damper and the vertical damper, and the degradation curve data under the corresponding service mileage and the environmental temperature are introduced, the Maxwell parameters of all suspension damping 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;

[0029] 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 dynamic performance evaluation.

[0030] Preferably, the nonlinear Maxwell hydraulic damper 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:

[0031] In the vehicle system nonlinear dynamics model, all anti-snaking dampers corresponding to the Maxwell force element 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;

[0032] According to the to-be-simulated mileage x, two groups of mileage x 1and x 2and their corresponding force-displacement characteristic curves are extracted from the measured database, which 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 closest two groups of temperature t1, t2 and their corresponding curves f’ k1 and f’ k2 and the corresponding force-velocity characteristic curves are f’ d1 and f’ d2, complete temperature interpolation, so as to obtain the force-displacement curve and the force-velocity curve coupled with the mileage-temperature;

[0033] 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, 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 wheelset, the bogie and the car body is output, and the wheel-rail vertical force and lateral force time history signals of all the wheels are generated, so that the vehicle dynamics performance simulation under the working condition is realized, and the simulation result is obtained.

[0034] Preferably, based on the obtained simulation result, the vehicle dynamics performance evaluation index is analyzed to complete the dynamics performance evaluation of the vehicle under the actual service mileage and the environmental temperature condition, which includes:

[0035] According to the wheel-rail vertical force and lateral force time history signals of all the wheels, the vehicle dynamics performance evaluation index is calculated and obtained, and a quantitative performance database under the working condition is formed;

[0036] The quantitative performance database is compared with the current specification, indexes exceeding the threshold value or close to the limit value are identified, and the corresponding mileage-temperature working condition is traced back, so that the potential dynamics risk point of the vehicle under the actual service mileage and the environmental temperature condition is determined;

[0037] Using the identified potential dynamics risk point, a maintenance or replacement suggestion for different service stages is generated, and then the dynamics performance evaluation of the vehicle under the actual service mileage and the environmental temperature condition is completed.

[0038] Preferably, the content of analyzing the vehicle dynamics performance evaluation index includes the stability of the bogie-car body coupled snaking motion, the running smoothness of the vehicle and the running safety performance of the vehicle.

[0039] In the second aspect, the application further provides a vehicle dynamics performance analysis system considering the performance degradation of suspension parameters, including:

[0040] The test module is used for testing the dynamic parameters of the anti-snaking damper and the secondary lateral damper, two types of high-speed bogie hydraulic dampers, on the hydraulic damper dynamic characteristic test bench, and obtaining the dynamic characteristic data of the two types of high-speed bogie hydraulic dampers under different running mileages and environmental temperature conditions;

[0041] The fusion module is used for fusing the dynamic characteristic data with the traditional Maxwell hydraulic damper model, establishing a nonlinear Maxwell hydraulic damper model, and simulating the frequency variation and amplitude variation nonlinear characteristics of the dynamic damping and stiffness of the damper;

[0042] The first establishing module is used for solving wheel-rail contact force based on coupling of Hertz theory and Kalker's simplified theory, and establishing a vehicle system dynamics model in a simulation software based on vehicle dynamics theory in combination with bogie components;

[0043] The second establishing module is used for integrating 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;

[0044] The setting driving module is used for setting parameters of the nonlinear Maxwell hydraulic damper model according to the obtained actual service mileage and environmental temperature of the vehicle, driving the vehicle system nonlinear dynamics model to perform dynamics simulation, and obtaining simulation results;

[0045] The analysis and evaluation module is used for analyzing vehicle dynamics performance evaluation indexes based on the obtained simulation results to complete dynamics performance evaluation of the vehicle under actual service mileage and environmental temperature conditions.

[0046] In a third aspect, the application further provides a vehicle dynamics performance analysis device considering performance degradation of suspension parameters, comprising:

[0047] A memory is used for storing a computer program;

[0048] A processor is used for implementing steps of the vehicle dynamics performance analysis method considering performance degradation of suspension parameters when the computer program is executed.

[0049] In a fourth aspect, the 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 steps of the vehicle dynamics performance analysis method considering performance degradation of suspension parameters.

[0050] The application has the following beneficial effects:

[0051] The application brings dynamic characteristic test data of the hydraulic damper into a nonlinear force element and further integrates the nonlinear force element into a vehicle dynamics model, so that vehicle dynamics behavior reproduction and performance evolution rule analysis under different operation mileages and environmental temperature conditions can be realized. The application can effectively reflect influence of suspension parameter degradation on vehicle dynamics performance, improves precision of a track vehicle dynamics simulation model and rationality of an analysis method, provides method guidance for vehicle dynamics analysis in a long-term service process, and has important theoretical research significance and engineering application value for track vehicle innovative design and intelligent operation and maintenance.

[0052] Other features and advantages of the present application will be set forth in the following specification, and in part will be apparent from the description, or can be learned by practice of the application. The objects and other advantages of the application will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings. BRIEF DESCRIPTION OF DRAWINGS

[0053] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments will be briefly introduced as follows. It should be understood that the following drawings only show some of the embodiments of the present application, and therefore should not be considered 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.

[0054] Figure 1 A flow chart of a vehicle dynamics performance analysis method considering suspension parameter performance degradation described in the embodiments of the present application;

[0055] Figure 2 A structure diagram of a vehicle dynamics performance analysis system considering suspension parameter performance degradation described in the embodiments of the present application;

[0056] Figure 3 A structure diagram of a vehicle dynamics performance analysis device considering suspension parameter performance degradation described in the embodiments of the present application;

[0057] Figure 4 A schematic diagram of a hydraulic shock absorber force-displacement hysteresis curve in a vehicle dynamics performance analysis method considering suspension parameter performance degradation described in the embodiments of the present application;

[0058] Figure 5 A schematic diagram of a hydraulic shock absorber spring-damping series force element model in a vehicle dynamics performance analysis method considering suspension parameter performance degradation described in the embodiments of the present application, wherein, x represents an excitation displacement, f represents a shock absorber output force, c d represents a damping coefficient of a series damping unit, k d represents a stiffness coefficient of a series spring unit, x d represents a displacement of an intermediate node;

[0059] Figure 6 An excitation displacement x , an output force f and an intermediate node displacement x in a vehicle dynamics performance analysis method considering suspension parameter performance degradation described in the embodiments of the present application; dTime signal schematic diagram.

[0060] In the figure: 701, test module; 702, fusion module; 703, first establishment module; 704, second establishment module; 705, setting driving module; 706, analysis and evaluation module; 800, vehicle dynamics performance analysis device considering suspension parameter performance degradation; 801, processor; 802, memory; 803, multimedia component; 804, I / O interface; 805, communication component. DETAILED DESCRIPTION

[0061] To make the objects, 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 some but not all of the embodiments of the present application. The components of the embodiments of the present application described and shown in the drawings herein 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. All other embodiments obtained by those of ordinary skill in the art without creative work based on the embodiments in the present application belong to the scope of protection of the present application.

[0062] It should be noted that: similar reference numerals and letters represent similar items in the following drawings, therefore, once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings. Meanwhile, in the description of the present application, the terms "first", "second" and the like are only used to distinguish description, and cannot be understood as indicating or implying relative importance.

[0063] Embodiment 1

[0064] The embodiment provides a vehicle dynamics performance analysis method considering suspension parameter performance degradation.

[0065] Referring to Figure 1 , the method includes steps S100, S200, S300, S400, S500 and S600.

[0066] S100, dynamic parameter testing of two types of high-speed bogie hydraulic dampers, anti-snaking dampers and secondary lateral dampers, is performed on a hydraulic damper dynamic characteristic test bench, and dynamic characteristic data of the two types of high-speed bogie hydraulic dampers under different running mileages and environmental temperature conditions is obtained;

[0067] It can be understood that the step S100 includes:

[0068] Step 11: Select anti-hunting, lateral, and vertical hydraulic vibration dampers with different service mileages as test specimens;

[0069] Step 12: On the hydraulic damper dynamic characteristic test bench, apply a simple harmonic excitation signal in the displacement control mode, and simultaneously collect the force feedback from the actuator as the output force signal of the damper. The simple harmonic excitation includes a sine wave with displacement amplitude and frequency input by the hydraulic actuator.

[0070] Step 13: Based on the simple harmonic excitation signal and the output force signal of the vibration damper, plot the force-displacement hysteresis curve, and calculate the equivalent stiffness and damping coefficient of the vibration damper under this excitation state based on the force-displacement hysteresis curve.

[0071] Step 14: Repeat step S13 to obtain stiffness and damping under all frequency-amplitude combinations, and place the tested vibration damper in an environmental chamber for ≥24 h, then change the test temperature and complete the corresponding test again. Replace the vibration damper with one of different service mileages, and repeat steps S12–S14 until a complete dynamic characteristic database of new and service mileage conditions is obtained.

[0072] It should be noted that hydraulic vibration dampers (anti-hunting dampers, lateral dampers, and vertical dampers) with different service mileages were selected as test specimens, such as those in new condition and those with 1.2 million km, 2.4 million km, and 4.8 million km of service. Then, dynamic characteristic tests were conducted on the tested dampers using a hydraulic vibration damper dynamic characteristic test bench. The test bench employed displacement control for loading, inputting a simple harmonic wave signal to the tested damper through the test bench's hydraulic actuator. The force signal fed back by the hydraulic actuator was recorded as the output force signal of the tested damper. The amplitude of the simple harmonic excitation displacement was... d 0 (unit: m), excitation frequency is f (Unit: Hz).

[0073] Next, based on the harmonic displacement excitation signal and the damper output force signal, a force-displacement hysteresis curve (also known as a dynamometer diagram) is plotted. The equivalent stiffness and damping coefficient of the damper under this excitation state can be calculated from this hysteresis curve. The damper force-displacement hysteresis curve is shown below. Figure 4 As shown, the horizontal axis represents the displacement of the shock absorber, and the vertical axis represents the output force of the shock absorber.

[0074] Among them, the force-displacement hysteresis curve of the hydraulic shock absorber F - x It is generally deflected in an elliptical shape 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 x-axis (the positive half of the horizontal axis) and the x-axis is x 0, and set the excitation displacement amplitude to 0. d0, the phase angle of the shock absorber can be calculated;

[0075] The calculation formula of the phase angle of the shock absorber in step 13 is as follows:

[0076]

[0077] In the formula, φ is the phase angle of the shock absorber output force hysteresis excitation displacement, x 0 is the force at the intersection of the deflection ellipse and the positive half axis of the x axis, d 0 is the excitation displacement amplitude;

[0078] The calculation formula of the equivalent stiffness and damping coefficient in step 13 is as follows:

[0079]

[0080] In the formula, 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 this excitation condition, k d is the equivalent stiffness coefficient of the shock absorber under this excitation condition, π is the circular constant, φ is the phase angle of the shock absorber output force hysteresis excitation displacement, d 0 is the excitation displacement amplitude.

[0081] 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 test 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.

[0082] In this step, the environmental test temperature is changed and the above steps are repeated to complete the dynamic characteristic test, wherein the test shock absorber is placed in the environmental temperature box for more than 24 hours before the dynamic characteristic test is performed, and the environmental temperature is recommended to be-60℃-60℃ with an interval of 10℃. 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 under certain service miles.

[0083] 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.

[0084] It can be understood that the step S200 includes S201, S202, S203 and S204.

[0085] S201, arranging the equivalent damping and equivalent stiffness corresponding to different excitation frequency-displacement amplitude combinations in the dynamic characteristic data as modeling data;

[0086] S202, substituting the modeling data into the damping-spring series force element model to obtain a traditional Maxwell hydraulic damper model; wherein the traditional Maxwell hydraulic damper model is composed of a damping unit and a spring unit in series as shown in Figure 5 .

[0087] S203, constructing a nonlinear force-displacement relationship curve based on the obtained measured data with the phase difference φ converted into the maximum spring deformation, and constructing a nonlinear force-velocity relationship curve with the velocity amplitude, so as to convert the traditional Maxwell hydraulic damper model into a nonlinear Maxwell force element model to match the dynamic working conditions with continuously changing excitation frequency and amplitude in vehicle operation;

[0088] S204, embedding the obtained nonlinear force-displacement relationship curve and nonlinear force-velocity relationship curve into the Maxwell model and carrying out numerical simulation to reproduce the damper frequency-amplitude coupling characteristics, and calling the frequency-variable or amplitude-variable results as needed to complete the nonlinear characteristic simulation of the damper dynamic parameters.

[0089] 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.

[0090] The equivalent damping and stiffness values measured under the above specific excitation frequency and displacement amplitude conditions are substituted into the damping-spring series force element model to complete the establishment of the traditional Maxwell hydraulic damper model. Wherein the excitation displacement x , the intermediate node displacement x d and the output force F time history signal and phase angle φ are shown in Figure 6 .

[0091] The above step of the traditional spring-damping series Maxwell model generally uses fixed stiffness and damping coefficient as model input to simulate the dynamic response under specific excitation frequency and amplitude conditions. However, the vibration excitation of the vehicle in the dynamic operation process is dynamically changing, therefore, it is necessary to further construct a nonlinear Maxwell force element model, i.e. replacing the fixed stiffness with a nonlinear force-displacement relationship curve and replacing 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.

[0092] Further, to obtain the nonlinear Maxwell force element model parameters, the amplitude of the harmonic excitation displacement of the damper is known as d 0 and the frequency is f , the maximum equivalent excitation velocity is , the maximum motion velocity of the series damping unit is . Assuming that the equivalent damping coefficient of the damper is c d , 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 f , the output force and the motion velocity of the damping unit under different excitation frequencies can be obtained. Therefore, the nonlinear force-velocity characteristic curve of the damping force element is obtained.

[0093] Further, the phase difference φ between the spring unit displacement and the harmonic displacement excitation displacement is known, and the maximum deformation of the spring unit can be calculated as . Since the spring unit and the damping unit in the Maxwell model are in series, the forces of the two units are the same, that is, , wherein represents the maximum output force of the spring unit. Therefore, the nonlinear force-displacement relationship curve of the spring unit is obtained.

[0094] 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 working condition. The dynamic characteristic test is carried out under a certain displacement amplitude harmonic excitation working condition, and the test frequency is set to 0.5 Hz and 1-12 Hz (step 1 Hz).

[0095] Using the obtained nonlinear force-velocity relationship curve and nonlinear force-displacement relationship curve, the Maxwell model is brought into the numerical simulation, the output force under the condition of harmonic displacement excitation is calculated, and then 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 damper dynamic parameters based on the measured dynamic characteristic data. Similar to the above steps, by changing the amplitude of the harmonic displacement excitation, the amplitude-dependent characteristic simulation of the damper dynamic parameters can be obtained.

[0096] According to the vehicle dynamics simulation analysis working condition mentioned later, the dynamic parameter frequency-dependent characteristic (a certain excitation displacement working condition) or the amplitude-dependent characteristic of the dynamic parameters (a certain excitation frequency working condition) of the damper is selected and brought into the vehicle dynamics model, to complete the simulation of the nonlinear characteristics of the suspension elements and the vehicle dynamics performance simulation analysis.

[0097] S300, based on the coupling of the Hertz theory and the Kalker simplified theory, wheel-rail contact force is solved, and a vehicle system dynamics model is established in a simulation software based on vehicle dynamics theory in combination with bogie components.

[0098] It can be understood that in this step S300, S301, S302 and S303 are included.

[0099] S301, the wheel-rail contact geometry is generated by inputting the LM type worn tread and the 60 kg / m rail profile through the wheel-rail contact geometry module, 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, the longitudinal, lateral and spin creep forces are solved in real time, and thus a wheelset system dynamics sub-model is established;

[0100] S302, taking the wheelset as the core, a multi-body dynamics topology of the whole vehicle is constructed by integrating steel springs, air springs, rubber nodes and hydraulic dampers according to the “rotating arm-axle box-frame-secondary suspension-vehicle body” hierarchical topology;

[0101] S303, based on the multi-body dynamics topology of the whole vehicle, 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 establishment of the vehicle system dynamics model is completed.

[0102] It should be noted that in the DAP-Rail software, the wheel-rail relationship is established, including the wheel-rail contact geometric 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 sub-model is established; further based on the wheelset system sub-model, rigid bodies such as axle box rotating arm, frame and vehicle body are added, and further one and two system suspension components such as steel spring, air spring, rubber node and hydraulic damper are added; finally, the integrator parameters and the calculation time 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.

[0103] S400, a nonlinear Maxwell hydraulic damper model is integrated into the vehicle system dynamics model, and a vehicle system nonlinear dynamics model considering suspension parameter performance degradation is established.

[0104] It can be understood that in this step S400, S401, S402 and S403 are included.

[0105] 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;

[0106] S402, map the nonlinear Maxwell force element to the hydraulic damper of each part of the vehicle, including at least anti-snake damper, lateral damper and vertical damper, and import the degradation curve data under the corresponding service mileage and environmental temperature, replace the Maxwell parameters of all suspension damping elements of the vehicle with the nonlinear stiffness and damping parameters, and form the vehicle system nonlinear dynamics model considering the performance degradation of suspension parameters at the topology level;

[0107] S403, set the variable step size implicit integrator parameters, simulation time and sampling frequency in the DAP-Rail solver setting module, load the track irregularity excitation, perform initialization and static balance solving, activate and calibrate the vehicle system nonlinear dynamics model considering the performance degradation of suspension parameters at the topology level, and generate the vehicle system nonlinear dynamics model considering the performance degradation of suspension parameters for dynamic performance evaluation.

[0108] It should be noted that with reference to the above steps, the Maxwell model parameters of the hydraulic dampers at different parts of the vehicle (such as anti-snake dampers, lateral dampers, vertical dampers, etc.) are replaced with nonlinear stiffness and damping parameters to establish a vehicle system nonlinear dynamics model considering the performance degradation of suspension parameters.

[0109] S500, according to the obtained actual service mileage and environmental temperature of the vehicle, set the nonlinear Maxwell hydraulic damper model parameters, and drive the vehicle system nonlinear dynamics model to perform dynamic simulation to obtain the simulation results.

[0110] It can be understood that in this step S500, S501, S502 and S503 are included.

[0111] S501, in the vehicle system nonlinear dynamics model, locate all the anti-snake damper corresponding Maxwell force element, and bind the obtained actual service mileage and environmental temperature of the vehicle to the external parameter table interface to form the subsequent mileage-temperature interpolation calling channel;

[0112] S502, according to the to-be-simulated mileage x , extract the two groups of mileages x 1 and x 2 closest to x from the measured database and their corresponding force-displacement characteristic curves are respectivelyf k1 and f k2 The reference curve at the mileage is obtained by linear interpolation; and in the same mileage data subset, the closest two groups of temperatures are selected as the interpolation points with the target environment temperature t, and the corresponding force-displacement characteristic curves are x 1, t 1, t 2 and the corresponding curves are f’ k1 and f’ k2 The corresponding force-velocity characteristic curves are 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;

[0113] S503, the force-displacement curve and the force-velocity curve are input into the nonlinear parameter table of the Maxwell force element of the anti-snaking damper, 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 wheelset, 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 the simulation result is obtained.

[0114] 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-snaking 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 working conditions obtained by the above steps, the dynamic characteristic data under the two closest running mileage measured by the test bench is selected according to the running mileage to be simulated, and the dynamic characteristic data of the damper under the running mileage working condition to be simulated is obtained according to the linear interpolation method.

[0115] Suppose the running mileage to be simulated is x , the two closest running mileage measured by the test bench is 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 dynamic characteristic data is linearly interpolated to obtain the force-displacement characteristic curve corresponding to the mileage x ​f k and force-velocity characteristic curve f d is:

[0116]

[0117] According to the above steps, the test data closest to the to-be-simulated mileage is selected as the interpolation data set of the to-be-analyzed ambient temperature data, i.e., the force-displacement characteristic curve and the force-velocity characteristic curve under different ambient temperature conditions at the running mileage; x

[0118] According to the selected damper dynamic characteristic data set at the specific mileage, according to the to-be-analyzed ambient temperature t , two groups of test bench measured temperatures t 1 and t 2 closest to the ambient temperature t are selected, and the corresponding force-displacement characteristic curves are f’ k1 and f’ k2 , and the corresponding force-velocity characteristic curves are f’ d1 and f’ d2 . According to the ambient temperature, linear interpolation is performed on the above dynamic characteristic data to obtain the force-displacement characteristic curve t corresponding to the ambient temperature f’ k and the force-velocity characteristic curve f’ d is:

[0119]

[0120] According to the force-displacement characteristic curve f’ k and the force-velocity characteristic curve f’ d obtained in the step, the stiffness and damping term parameters of the hydraulic damper in the vehicle system nonlinear dynamics model in the DAP-Rail software are set, and the setting of the damper nonlinear parameters is completed;

[0121] Further, the numerical integration module of the DAP-Rail software 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.

[0122] Among them, the dynamics simulation mainly refers to solving the vehicle system dynamics equation, obtaining the displacement and velocity signals of the wheel set, frame and vehicle body motion degrees of freedom, and outputting the wheel-rail system force, suspension system force and other signals.​

[0123]

[0124] where M represents the vehicle system mass matrix, C represents the system damping matrix, K represents the system stiffness matrix, Y represents the system motion displacement freedom degree vector, and V and A 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 S represents the suspension system force vector (excluding hydraulic shock absorbers); F d represents the output force vector of the hydraulic shock absorber.

[0125] 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.

[0126] It can be understood that in this step S600, S601, S602 and S603 are included, wherein:

[0127] According to the time history signals of the wheel-rail vertical force and lateral force of all wheels, the vehicle dynamics performance evaluation index is calculated and obtained, and a quantitative performance database under the working condition is formed;

[0128] The quantitative performance database is compared with the current 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;

[0129] 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.

[0130] 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 the stability of the snake movement (judged by the frame lateral acceleration), the running stability (judged by the stability index and the comfort index) and the running safety performance (judged by the derailment coefficient, the wheel load reduction rate and the 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.

[0131] Embodiment 2:

[0132] As shown in Figure 2 , the present embodiment provides a vehicle dynamics performance analysis system considering the performance degradation of suspension parameters, as shown inFigure 2 The system comprises:

[0133] The test module 701 is configured to test dynamic parameters of the anti-snaking damper and the secondary lateral damper on the hydraulic damper dynamic characteristic test bench, and obtain dynamic characteristic data of the two types of high-speed bogie hydraulic dampers under different running mileages and environmental temperature conditions.

[0134] The fusion module 702 is configured to fuse the dynamic characteristic data with a traditional Maxwell hydraulic damper model, establish a nonlinear Maxwell hydraulic damper model, and simulate frequency variation and amplitude variation nonlinear characteristics of the dynamic damping and stiffness of the damper.

[0135] The first establishment module 703 is configured to solve wheel-rail contact force 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.

[0136] The second establishment module 704 is configured to integrate the nonlinear Maxwell hydraulic damper model into the vehicle system dynamics model, and establish a vehicle system nonlinear dynamics model considering performance degradation of suspension parameters.

[0137] The setting and driving module 705 is configured to set parameters of the nonlinear Maxwell hydraulic damper model according to the obtained actual service mileages and environmental temperatures of the vehicle, drive the vehicle system nonlinear dynamics model to perform dynamics simulation, and obtain simulation results.

[0138] The analysis and evaluation module 706 is configured to analyze a vehicle dynamics performance evaluation index based on the obtained simulation results, and complete dynamics performance evaluation of the vehicle under actual service mileages and environmental temperature conditions.

[0139] It should be noted that, as for 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.

[0140] Embodiment 3

[0141] 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.

[0142] 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 exemplary embodiment. As shown in Fig. 8, the vehicle dynamics performance analysis device 800 considering performance degradation of suspension parameters comprises a test module 801, a fusion module 802, a first establishment module 803, a second establishment module 804, a setting and driving module 805, and an analysis and evaluation module 806. Figure 3As shown, the vehicle dynamics performance analysis device 800 considering suspension parameter performance degradation includes a processor 801 and a memory 802. The vehicle dynamics performance analysis device 800 considering suspension parameter performance degradation also includes one or more of a multimedia component 803, an I / O interface 804, and a communication component 805.

[0143] 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.

[0144] 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.

[0145] In another example embodiment, a computer readable storage medium including program instructions that, when executed by a processor, implement the steps of the above-mentioned vehicle dynamics performance analysis method considering suspension parameter performance degradation is also provided. For example, the computer readable storage medium can be the above-mentioned memory 802 including program instructions that 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.

[0146] Embodiment 4:

[0147] Corresponding to the above method embodiments, a readable storage medium is also provided in this embodiment, and the readable storage medium described below can be referred to in conjunction with the above-mentioned vehicle dynamics performance analysis method considering suspension parameter performance degradation.

[0148] The computer program stored on the readable storage medium implements the steps of the above-mentioned vehicle dynamics performance analysis method considering suspension parameter performance degradation of the method embodiments when executed by a processor.

[0149] 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.

[0150] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0151] 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 variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for analyzing vehicle dynamics performance considering the degradation of suspension parameters, characterized in that, include: On the hydraulic damper dynamic characteristic test bench, dynamic parameter tests were conducted on two types of high-speed bogie hydraulic dampers: anti-hunting damper and secondary lateral damper, to obtain their dynamic characteristic data under different operating mileage and ambient temperature conditions. By integrating dynamic characteristic data with the traditional Maxwell hydraulic damper model, a nonlinear Maxwell hydraulic damper model is established to simulate the frequency- and amplitude-variable nonlinear characteristics of the damper's dynamic damping and stiffness. The wheel-rail contact force is solved by coupling Hertz theory and Kalk simplified theory, and a vehicle system dynamic model is established in simulation software based on vehicle dynamics theory, combined with bogie components. The nonlinear Maxwell hydraulic damper model is integrated into the vehicle system dynamics model to establish a nonlinear dynamics model of the vehicle system that considers the performance degradation of suspension parameters; Based on the actual service mileage and ambient temperature of the vehicle, the parameters of the nonlinear Maxwell hydraulic damper model were set, and the nonlinear dynamic model of the vehicle system was driven to perform dynamic simulation to obtain the simulation results. Based on the simulation results, the vehicle dynamics performance evaluation index is analyzed to complete the dynamics performance evaluation of the vehicle 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 damper dynamic characteristic test bench, dynamic parameter tests were conducted on two types of high-speed bogie hydraulic dampers: anti-hunting dampers and secondary lateral dampers. Dynamic characteristic data were obtained under different operating mileage and ambient temperature conditions, including: Step 11: Select anti-hunting vibration dampers and secondary lateral vibration dampers with different service mileages as test specimens; Step 12: On the hydraulic damper dynamic characteristic test bench, apply a simple harmonic excitation signal in the displacement control mode, and simultaneously collect the force feedback from the actuator as the output force signal of the damper. The simple harmonic excitation includes a sine wave with displacement amplitude and frequency input by the hydraulic actuator. Step 13: Based on the simple harmonic excitation signal and the output force signal of the vibration damper, plot the force-displacement hysteresis curve, and calculate the equivalent stiffness and damping coefficient of the vibration damper under this excitation state based on the force-displacement hysteresis curve. Step 14: Repeat step S13 to obtain stiffness and damping under all frequency-amplitude combinations, and place the tested vibration damper in an environmental chamber for ≥24 h, then change the test temperature and complete the corresponding test again. Replace the vibration damper with one of different service mileages, and repeat steps S12–S14 until a complete dynamic characteristic database of new and service mileage conditions is obtained.

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 vibration damper under this excitation state are calculated based on the force-displacement hysteresis curve. The calculation formulas for the equivalent stiffness and damping coefficient are as follows: In the formula, φ The output force of the vibration damper lags behind the phase angle of the excitation displacement. x 0 represents the force at the intersection of the deflecting ellipse and the positive x-axis. d 0 represents the excitation displacement amplitude; Based on the phase angle, the equivalent damping and stiffness coefficients of the vibration damper are calculated using the following formulas: In the formula, A c Let ω be the area enclosed by the force-displacement hysteresis curve, and ω be the excitation angular frequency. c d This is the equivalent damping coefficient of the vibration damper under this excitation condition. k d This is the equivalent stiffness coefficient of the vibration damper under this excitation condition. π Pi φ The output force of the vibration damper lags behind the phase angle of the excitation displacement. d 0 represents the excitation displacement amplitude.

4. The vehicle dynamics performance analysis method considering suspension parameter performance degradation according to claim 1, characterized in that, The process involves fusing dynamic characteristic data with a traditional Maxwell hydraulic damper model to establish a nonlinear Maxwell hydraulic damper model. This model simulates the frequency- and amplitude-dependent nonlinear characteristics of the damper's dynamic damping and stiffness, including: The equivalent damping and equivalent stiffness corresponding to different excitation frequency-displacement amplitude combinations in the dynamic characteristic data are collected and used as modeling data. Substituting the modeling data into the damping-spring series force element model, we obtain the traditional Maxwell hydraulic damper model; Based on the obtained measured data, a nonlinear force-displacement relationship curve is constructed using the maximum spring deformation calculated by the phase difference φ, and a nonlinear force-velocity relationship curve is constructed using the velocity amplitude. This transforms the traditional Maxwell hydraulic damper model into a nonlinear Maxwell force element model to match the dynamic working condition of continuously changing excitation frequency amplitude during vehicle operation. The obtained nonlinear force-displacement and nonlinear force-velocity curves are embedded into the Maxwell model and numerical simulation is carried out to reproduce the frequency-amplitude coupling characteristics of the vibration damper. The frequency-variable or amplitude-variable results can be called as needed to complete the simulation of the nonlinear characteristics of the frequency-variable and amplitude-variable dynamic parameters of the vibration damper.

5. The vehicle dynamics performance analysis method considering suspension parameter performance degradation according to claim 1, characterized in that, The method involves solving the wheel-rail contact force using a coupling of Hertzian theory and Kalk simplified theory, and establishing a vehicle system dynamic model in simulation software based on vehicle dynamics theory, incorporating bogie components. This model includes: By inputting the LM-type worn tread and the profile of a 60 kg / m rail into the wheel-rail contact geometry module, the wheel-rail contact geometry is generated. Hertz theory is used to calculate the wheel-rail normal force and the major and minor semi-axes of the contact ellipse. The wheel-rail normal force and the major and minor semi-axes of the contact ellipse are then input into the Kalk simplified theory to solve the longitudinal, lateral and spin creep forces in real time, thereby establishing a dynamic sub-model of the wheelset system. With the wheelset as the core, and following the hierarchical topology of "axle box swing arm - primary suspension - frame - secondary suspension - vehicle body", steel springs, air springs, rubber nodes and hydraulic shock absorbers are integrated to construct the multi-body dynamics topology of the whole vehicle. Based on the multibody dynamics topology of the vehicle, the parameters of the variable step size implicit integrator, the simulation duration of 30 s and the sampling frequency of 1000 Hz were configured in the DAP-Rail solver setting module, and the German high-interference track spectrum was loaded as the track excitation. Initialization and static balance solutions were performed to complete the establishment of 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 integration of the nonlinear Maxwell hydraulic damper model into the vehicle system dynamics model establishes a nonlinear dynamics model of the vehicle system that considers the degradation of suspension parameter performance, including: Based on the vehicle system dynamics model, the Maxwell-type hydraulic damper force element template of DAP-Rail is called, and the fixed stiffness and fixed damping terms in the force element parameter list are replaced with nonlinear force-displacement relationship curves and nonlinear force-velocity relationship curves, respectively, to generate nonlinear Maxwell force elements for a single damper. Nonlinear Maxwell force elements are batch mapped to hydraulic dampers in various parts of the vehicle, including at least anti-hunting dampers and secondary lateral dampers. Degradation curve data at corresponding service mileage and ambient temperature are imported, and 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 that considers the performance degradation of suspension parameters at the topology level. Within the DAP-Rail solver settings module, the parameters of the variable step size implicit integrator, simulation duration, and sampling frequency are set. Track irregularity excitation is applied, and initialization and static balance solutions are performed to activate and calibrate the topology layer to form a nonlinear dynamic model of the vehicle system considering the performance degradation of suspension parameters. This generates a nonlinear dynamic model of the vehicle system considering the performance degradation of suspension parameters for dynamic performance evaluation.

7. The vehicle dynamics performance analysis method considering suspension parameter performance degradation according to claim 1, characterized in that, Based on the obtained 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, including: In the nonlinear dynamics model of the vehicle system, Maxwell force elements corresponding to all anti-hunting dampers are located, and the obtained actual service mileage and ambient temperature input ports of the vehicle 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 as x, extract the two sets of mileage closest to x from the actual measurement database. x 1 and x 2 and its corresponding force-displacement characteristic curves are respectively f k1 and f k2 A baseline curve for mileage x is obtained through linear interpolation; and within the same subset of mileage data, using the target ambient temperature t as the interpolation point, the two closest sets of temperatures t1 and t2 and their corresponding curves are selected. f’ k1 and f’ k2 The corresponding force-velocity characteristic curves are as follows: f’ d1 and f’ d2 Temperature interpolation is then performed to obtain the mileage-temperature coupled force-displacement curve and force-velocity curve. The force-displacement curves and force-velocity curves are input into the nonlinear parameter table of the Maxwell force element of the anti-hunting damper to complete the parameter setting. Then, the DAP-Rail numerical integration module is started to solve the vehicle system dynamic equations, output the displacement-velocity time history of the wheelset, frame and body, and generate the wheel-rail vertical force and lateral force time history signals of all wheels to realize the vehicle dynamic performance simulation 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, vehicle dynamic performance evaluation indicators are analyzed to complete the dynamic performance assessment of the vehicle under actual service mileage and ambient temperature conditions, including: Based on the time-history signals of the vertical and lateral forces of all wheels, vehicle dynamic performance evaluation indicators are calculated to form a quantitative performance database under this working condition. By comparing the quantitative performance database with current specifications, identifying indicators that exceed or approach the threshold, and tracing back to the corresponding mileage-temperature conditions, potential dynamic risks of the vehicle under actual service mileage and ambient temperature conditions can be determined. By utilizing the identified potential dynamic risks, maintenance or replacement recommendations are generated for different service stages, thereby completing the dynamic performance evaluation of the vehicle 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 evaluation indicators for vehicle dynamics performance include bogie-car body coupled snake 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 as described in claim 1, characterized in that, include: Test module: Used on the hydraulic damper dynamic characteristic test bench to test the dynamic parameters of two types of high-speed bogie hydraulic dampers: anti-hunting damper and secondary lateral damper, and to obtain their dynamic characteristic data under different operating mileage and ambient temperature conditions. Fusion module: Used to fuse dynamic characteristic data with the traditional Maxwell hydraulic damper model to establish a nonlinear Maxwell hydraulic damper model to simulate the frequency- and amplitude-variable nonlinear characteristics of the damper's dynamic damping and stiffness. The first 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 dynamic model in simulation software based on vehicle dynamics theory, in conjunction with bogie components. The second module is used to integrate the nonlinear Maxwell hydraulic damper model into the vehicle system dynamics model, and to establish a nonlinear dynamics model of the vehicle system that takes into account the performance degradation of suspension parameters. The drive module is set up to determine the parameters of the nonlinear Maxwell hydraulic damper model based on the actual service mileage and ambient temperature of the vehicle, and to drive the nonlinear dynamic model of the vehicle system to perform dynamic simulation and obtain simulation results. Analysis and Evaluation Module: Based on the obtained simulation results, this module analyzes the vehicle's dynamic performance evaluation indicators to complete the dynamic performance evaluation of the vehicle under actual service mileage and ambient temperature conditions.

Images