Tire lateral deviation and longitudinal slip composite slip characteristic simulation method, equipment, medium and program

Abstract

The invention relates to the technical field of tire dynamics, in particular to a finite element simulation method, device, medium and program for lateral deviation and longitudinal slip composite slip characteristics of a tire. The invention provides a tire lateral deviation and longitudinal slip composite slip characteristic finite element simulation method which comprises the steps of finite element pretreatment, two-dimensional inflation and three-dimensional loading modeling analysis, steady-state simulation analysis, dynamic lateral deviation and longitudinal slip composite slip characteristic simulation modeling analysis and simulation result extraction, the method is high in simulation precision, and meanwhile the simulation efficiency is considered.

Description

Technical Field

[0001] The present invention relates to the technical field of tire dynamics, and in particular to a method, device, medium and program for simulating the composite slip characteristics of tire lateral slip. Background Art

[0002] The compound slip characteristics of tires under lateral and longitudinal sliding conditions are the mechanical characteristics of tires under lateral and longitudinal sliding conditions. When modeling tire dynamics, it is necessary to input compound slip characteristics data of multiple working conditions. For example, if 5 loads are input and 4 working conditions are input for each load, a total of 20 working conditions data are required. Currently, it is mainly obtained through actual measurement, which is not only costly but also time-consuming. If the tire design is optimized and improved, it is obviously difficult to meet the development requirements through actual measurement methods.

[0003] Therefore, it is necessary to establish a simulation model of the combined slip characteristics of lateral and longitudinal slip. On the one hand, it can replace actual measurement to a certain extent, save product development costs and shorten product development cycle; on the other hand, it can meet the early virtual matching development requirements of tires put forward by automobile companies for tire matching.

[0004] In the prior art, the invention patent application (publication number: CN114462282A Publication date: 20220510) discloses a finite element simulation method for the steady-state characteristics of tire roll, slant and longitudinal slip. This method uses a scanning method to solve the roll, slant and longitudinal slip. It takes a long time to calculate a complete working condition. If the finite element simulation model is relatively complex, the calculation efficiency is low and the simulation cost is high. In addition, as the calculation time increases, the probability of mesh distortion also increases. The applicant's invention patent application (publication number: CN117973143A Publication date: 20240503) discloses a finite element simulation method for tire slant characteristics. This method splits the slant simulation model file into multiple files for calculation, avoiding the problem of mesh distortion during long-term calculations, and has high simulation accuracy and efficiency. The applicant's invention patent application (publication number: CN118278248A Publication date: 20240702) discloses a finite element simulation method for tire longitudinal slip characteristics. This method splits the model file into multiple files for calculation and conducts longitudinal slip characteristics simulation analysis. During the calculation process, the grid is not easily distorted, the simulation accuracy is high, and the simulation efficiency is taken into account. However, the latter two methods have not yet considered the conditions of the simultaneous existence of side slip and longitudinal slip. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a finite element simulation method for the compound slip characteristics of tire lateral longitudinal slip, which simulates the compound slip characteristics of tire lateral longitudinal slip by performing finite element pre-processing, two-dimensional inflation and three-dimensional loading modeling analysis, steady-state simulation analysis, dynamic lateral longitudinal slip compound slip simulation modeling analysis, simulation result extraction and other steps. In the finite element simulation of dynamic lateral longitudinal slip compound slip, explicit analysis is used to avoid the problem of non-convergence. The friction property between the tire and the road surface adopts the friction model obtained by fitting the friction test of the tread rubber material, and different slip rate values ​​can be selected independently and flexibly, thereby achieving the purpose of simulating the compound slip characteristics of tire lateral longitudinal slip with high precision and high efficiency.

[0006] In order to achieve the above-mentioned purpose, the present invention adopts the following technical solutions: A finite element simulation method for tire sideways longitudinal composite slip characteristics, characterized in that the method comprises the following steps: 1) Finite element pre-processing; 1.1) Draw a material distribution map; 1.2) Grid division; 2) Static loading analysis modeling; 2.1) 2D inflation simulation modeling and analysis; 2.2) Perform three-dimensional loading simulation modeling, set the tire center axis as the Y axis, the road surface load along the Z axis, rotate the road surface by an angle α, which is the tire side slip angle, and establish a local coordinate system, with the direction along the road surface as the X' axis and the Z' axis opposite to the Z axis; 3) Establish two STEADY STATE TRANSPORT analysis steps. In analysis step 1, the given angular velocity is less than the steady-state angular velocity, i.e. braking. In analysis step 2, the given angular velocity is greater than the steady-state angular velocity, i.e. driving. The RF1 curve of the road surface or rim reference point that changes with the angular velocity is calculated. The angular velocity value when RF1 is 0 can be obtained through linear fitting. This value is the steady-state angular velocity. 4) Substitute the steady-state angular velocity into the STEADY STATE TRANSPORT analysis step, calculate the steady-state rolling ODB file, extract the tire sinking amount in the steady state, and calculate the road surface information in the steady state; 5) Dynamic longitudinal sliding characteristics simulation modeling and analysis; 5.1) Import information on components, constraints, surfaces, and road surfaces in steady state from static analysis; 5.2) Set the mass and moment of inertia of the wheels and road surface; 5.3) Set the friction properties between the rim and the tire, and between the tire and the road surface; 5.4) Perform uniform rolling analysis, release the constraint of the rim reference point 5, i.e., rotation along the Y axis, and apply steady-state angular velocity, while keeping other directions fixed. Release the constraint of the road surface reference point in the X' and Z' axes, while keeping other directions fixed. Set the air pressure and load, apply the set moving speed in the horizontal direction of the road surface, i.e., the X' axis, and set the historical variable output; 5.5) Perform a lateral slip analysis, and perform a restart analysis based on the uniform rolling analysis. The rim reference point and the road reference point maintain the constraint state of the first step, and the road surface is kept in uniform motion along the X' axis. Apply an angular velocity to the 5 direction of the rim reference point, that is, the tire rotation direction around the Y axis. Set the angular velocity amplitude function to change from the steady-state angular velocity to the given angular velocity from 0s to t1s. From t1s to t2s, keep the angular velocity unchanged. Set the historical variable output, and set the output time interval to ts, then output 1 / t data per second. 5.6) Select a series of angular velocities and use a self-written program to generate a series of input files for side slip analysis; 5.7) Submit for batch solution, and use self-written program to automatically extract and post-process the results.

[0007] Preferably, in the step 1), the tire material distribution map is finely gridded to distinguish various tire components.

[0008] Preferably, in step 2.1), all skeleton materials adopt the rebar model, wherein the belt is added with a lift equation, and the elongation and belt radius are calculated by designing the belt drum diameter and the design outer diameter.

[0009] Preferably, in step 5.3), a friction model between the road surface and the tire is added, the friction model includes slip velocity and contact pressure parameters, and the friction coefficient between the tire and the rim is set to a range between 0.1 and 0.5.

[0010] Preferably, the uniform rolling analysis calculation time range in step 5.4) is set to be between 0.05s and 0.2s.

[0011] Preferably, in step 5.5), the calculation time of the lateral slip analysis step is set to t1 in the range of 0.05s to 0.15s, and t2 is set to 0.05s to 0.5s. In the historical variable output, 4 variables of rim reference points RF1, RF2, RM3, and RF3 are set, among which RF3 is used to refer to whether the load is stable during the calculation process. The maximum setting of t is 0.0025s, that is, at least 400 points are output per second.

[0012] Preferably, in step 5.6), the selected slip rates should include the maximum and minimum slip rates, i.e., critical values, and the rest are selected according to actual conditions, and each slip rate corresponds to a calculation file.

[0013] As a preferred embodiment, in step 5.7), data is extracted from each calculation result file, and the time history of the side slip analysis step is extracted as the last t L s data, each variable has t L / t data points, and the corresponding variable values ​​under the slip rate are obtained by averaging these data points. The variable values ​​include RF1, RF2, RM3, RF3, etc. Points are plotted with slip rate as the horizontal coordinate and variable value RF1 (longitudinal force) as the vertical coordinate to obtain a scatter plot of longitudinal force changing with slip rate, or a straight line or curve is connected in order of slip rate from small to large to obtain a curve plot of longitudinal force changing with slip rate. Similarly, a scatter plot or curve plot of RF2, RM3 and other variable values ​​changing with slip rate can be obtained.

[0014] Furthermore, the present invention also discloses a method for simulating the compound slip characteristics of the tire's lateral longitudinal slip, and the method is applied in the simulation of the compound slip characteristics of the tire's lateral longitudinal slip.

[0015] The present invention adopts the above-mentioned technical solution, takes into account various components of the tire, and each rubber and frame material is accurately measured and fitted. The friction model obtained by actual measurement and identification is adopted to ensure the simulation accuracy. At the same time, by selecting multiple different slip rates for simulation, the number of slip rate analyses and the analysis step time can be controlled, avoiding the grid distortion problem that may be caused by too long simulation time, and taking into account the simulation efficiency, so that the simulation efficiency is significantly improved and the simulation cost is greatly reduced.

[0016] The beneficial effects of the present invention are as follows: 1. The present invention takes into account the friction model between various tire components and the road surface and the tire, and has high simulation accuracy; 2. In addition to several key slip rate values, the present invention can flexibly select other slip rate values ​​for simulation, and the simulation efficiency is high; 3. Since a single slip value is used for calculation, the calculation time is short, thus avoiding the mesh distortion problem that may be caused by long simulation time. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a flow chart of the method of the present invention.

[0018] Figure 2 It is a 205 / 55R16 tire specification finite element two-dimensional simulation model.

[0019] Figure 3It is a finite element 3D simulation model of 205 / 55R16 tire specification.

[0020] Figure 4 It is the contact pressure distribution at a certain moment when the tire specification is 205 / 55R16 at 230kPa air pressure, 6500N load, and sideslip angle of -2°, and the slip rate is 2.5%.

[0021] Figure 5 It is a scatter plot of simulation results of 205 / 55R16 tire specification under 230kPa air pressure, 6500N load and sideslip angle of -2°, with slip rate as the horizontal axis and longitudinal force as the vertical axis.

[0022] Figure 6 It is a scatter plot of simulation results of 205 / 55R16 tire specification under 230kPa air pressure, 6500N load and sideslip angle of -2°, with slip rate as the horizontal axis and lateral force as the vertical axis.

[0023] Figure 7 It is a scatter plot of simulation results of 205 / 55R16 tire specification under 230kPa air pressure, 6500N load and sideslip angle of -2°, with slip rate as the horizontal axis and righting torque as the vertical axis. DETAILED DESCRIPTION

[0024] The method of the invention is used for simulation analysis of the side slip and longitudinal composite slip characteristics of various types of tires.

[0025] The present invention is further described below by means of an example. This embodiment is implemented on the premise of the technical solution of the present invention, but the protection scope of the present invention is not limited to the following example.

[0026] This embodiment takes the tire specification of 205 / 55R16 as an example, and establishes a finite element simulation analysis model of the combined slip characteristics of the sideslip angle of -2° under the air pressure of 230 kPa and the load of 6500 N.

[0027] Use AutoCAD to draw the material distribution map, export it as a dxf file, and then import it into Hypermesh software for mesh division. The minimum unit size is controlled above 0.5mm as much as possible. After the division is completed, export the inp file and then import it into ABAQUS / CAE software for two-dimensional inflation modeling analysis. It has longitudinal grooves and an inflation pressure of 230kPa. The rubber material uses the yeoh model and the skeleton material uses the rebar model. The rubber includes 13 parts including the tread, sidewall, and base rubber. The skeleton material includes 6 parts including belt steel wire and carcass cord. Through the belt drum diameter, the designed outer diameter and the size of the material distribution map, it can be calculated that the elongation of belt layer 1 and belt layer 2 are 4.92% and 4.90% respectively, and the belt radii are 291.75 and 292.75 respectively. The rim uses an analytical rigid body model. The two-dimensional inflation model is as follows: Figure 2 As shown in the figure, the model has 1480 nodes and 1351 units. The ABAQUS / Standard solver is used to perform inflation simulation under 230 kPa air pressure.

[0028] Generate a 3D model through the SYMMETRIC MODEL GENERATION function, divide the circumference into 60 sections, establish a local coordinate system for the road surface, rotate the road surface by 2°, and set the center distance between the road surface and the wheel rim to 320 mm. Input the road surface information into the 3D model inp file. The finite element 3D model is as follows: Figure 3 As shown, the ABAQUS / Standard solver is used to carry out loading analysis under the condition of load of 6500N and 230kPa.

[0029] After the three-dimensional loading calculation is completed, a steady-state simulation is performed. Two STEADY STATE TRANSPORT analysis steps are established. The linear velocity of the given rim reference point is 16666.66 mm / s. The given angular velocity in analysis step 1 is 53.5 rad / s, and the braking calculation is performed. The given angular velocity in analysis step 2 is 54.5 rad / s, and the driving calculation is performed. The RF1 curve of the rim reference point that changes with the angular velocity is calculated. The angular velocity value when RF1 is 0 is obtained through linear fitting, that is, the steady-state angular velocity is 53.91 rad / s. Substitute 53.91 rad / s into the STEADYSTATE TRANSPORT analysis step, calculate the steady-state rolling odb file, extract the RF1 result to be 9.78929 N, and the force value is less than 10 N, which meets the requirements. The road surface movement distance of the tire under steady-state state is extracted to be 34.8506 mm, and the distance between the road surface and the rim center under steady-state conditions is calculated to be 285.1494 mm.

[0030] After the steady-state calculation is completed, the dynamic lateral slip and longitudinal composite slip characteristics simulation modeling analysis is carried out. Import the components in the static analysis, import the skeleton material embedding constraints, the road reference point constraints and the rim reference point rigid body constraints, input the rim and road geometry information, import the tire and rim, the inner cavity, and the rim and tire contact surface, and set the Z-axis coordinate of the road surface under the load of 6500N to -285.1494, and the road surface length is 20m. Set the wheel weight to 9.25kg, and the moments of inertia in the X, Y, and Z directions to 110, 1200, and 110 respectively. According to relevant literature and actual measurements, the friction model formula is established, taking into account the influence of contact pressure and slip speed on friction performance. Set the friction coefficient between the tire and the rim to 0.3.

[0031] Establish a uniform rolling analysis step, select Dynamic, Explicit analysis, set the air pressure to 230kPa, the load to 6500N, apply a moving speed of 60km / h, or 16667mm / s, to the horizontal direction of the road surface, i.e. the X' axis direction, in the local coordinate system, and apply a steady-state angular velocity of 53.91rad / s to the 5 directions of the rim reference point, i.e. the tire rotation direction around the Y axis, and set the calculation time to 0.1s. The historical variable output is set to the four variables RF1, RF2, RM3, and RF3 of the rim reference point, of which RF3 is used to refer to whether the load is stable during the calculation process, and the time interval is set to 0.00125s, i.e. 800 points are output per second. Submit the ABAQUS / Explicit calculation after completion.

[0032] Establish the side slip analysis step, which restarts the analysis based on the uniform rolling analysis, keeps the road surface in uniform motion, applies angular velocity to the 5 directions of the rim reference point, that is, the tire rotation direction around the Y axis, and sets the amplitude function of the angular velocity to change from 53.91rad / s to the given angular velocity W from 0s to 0.1s, and the corresponding slip rate is SR. From 0.1s to 0.2s, the angular velocity W, that is, the slip rate SR, remains unchanged, and the historical variable output is set the same as the first step. SR takes -30%, -25%, -20%, -15%, -10%, -7.5%, -5%, -2.5%, 0%, 2.5%, 5%, 7.5%, 10%, 15%, 20%, 25%, 30%, a total of 17 points, each point corresponds to an input file, that is, 17 input files need to be generated, which can be quickly generated through the program.

[0033] 17 input files are submitted to ABAQUS / Explicit for calculation in batches. Each input file needs to be calculated for 0.2 seconds, plus the calculation time of the uniform rolling analysis step, a total of 3.5 seconds. If the calculation is calculated by scanning the slip rate, it will take about 15 seconds, and the total calculation time is less than a quarter of the scanning method. Therefore, the calculation efficiency is significantly improved, and the mesh distortion problem that may be caused by too long simulation time is avoided. Figure 4 is the contact pressure distribution at a certain moment when the slip rate is 2.5%.

[0034] Data is extracted from each abaqus calculation result odb file, and the data of the time history of the lateral longitudinal slip analysis step from 0.15s to 0.2s are extracted. Each variable has 40 data points in total. The corresponding variable value under the slip rate is obtained by averaging these 40 data points. Plot points with the slip rate as the horizontal coordinate and the longitudinal force (RF1) as the vertical coordinate to obtain a scatter plot with the slip rate as the horizontal coordinate and the longitudinal force as the vertical coordinate. Similarly, scatter plots of the lateral force (RF2) and the restoring moment (RM3) can be drawn. In addition, the vertical force RF3 results under each slip rate can also be extracted to measure whether the load control is stable. Figure 5 , Figure 6 and Figure 7 They are scatter plots of simulation results with slip rate as the horizontal axis and RF1, RF2 and RM3 as the vertical axis.

[0035] The above is a description of the embodiments of the present invention. Through the above description of the disclosed embodiments, professionals and technicians in the field can implement or use the present invention. Various modifications to these embodiments will be apparent to professionals and technicians in the field. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown in this article, but will conform to the widest range consistent with the principles and novelties disclosed herein.

Claims

1. A finite element simulation method for tire sideways slip composite slip characteristics, characterized in that: The method comprises the following steps: 1) Finite element pre-processing; 1.1) Draw a material distribution map; 1.2) Grid division; 2) Static loading analysis modeling; 2.1) 2D inflation simulation modeling and analysis; 2.2) Perform three-dimensional loading simulation modeling, set the tire center axis as the Y axis, the road surface load along the Z axis, rotate the road surface by an angle α, which is the tire side slip angle, and establish a local coordinate system, with the direction along the road surface as the X' axis and the Z' axis opposite to the Z axis; 3) Establish two STEADY STATE TRANSPORT analysis steps. In analysis step 1, the given angular velocity is less than the steady-state angular velocity, i.e. braking. In analysis step 2, the given angular velocity is greater than the steady-state angular velocity, i.e. driving. The RF1 curve of the road surface or rim reference point that changes with the angular velocity is calculated. The angular velocity value when RF1 is 0 is obtained through linear fitting, which is the steady-state angular velocity. 4) Substitute the steady-state angular velocity into the STEADY STATE TRANSPORT analysis step, calculate the steady-state rolling ODB file, extract the tire sinking amount in the steady state, and calculate the road surface information in the steady state; 5) Dynamic longitudinal sliding characteristics simulation modeling and analysis; 5.1) Import information including components, constraints, surfaces, and road surface in steady state in static analysis; 5.2) Set the mass and moment of inertia of the wheels and road surface; 5.3) Set the friction properties between the rim and the tire, and between the tire and the road surface; 5.4) Perform uniform rolling analysis, release the constraint of the rim reference point 5, i.e., rotation along the Y axis, and apply steady-state angular velocity, while keeping other directions fixed. Release the constraint of the road surface reference point in the X' and Z' axes, while keeping other directions fixed. Set the air pressure and load, apply the set moving speed in the horizontal direction of the road surface, i.e., the X' axis, and set the historical variable output; 5.5) Perform a lateral slip analysis, and perform a restart analysis based on the uniform rolling analysis. The rim reference point and the road reference point maintain the constraint state of the first step, and the road surface is kept in uniform motion along the X' axis. Apply an angular velocity to the 5 direction of the rim reference point, that is, the tire rotation direction around the Y axis. Set the angular velocity amplitude function to change from the steady-state angular velocity to the given angular velocity from 0s to t1s. From t1s to t2s, keep the angular velocity unchanged. Set the historical variable output, and set the output time interval to ts, then output 1 / t data per second. 5.6) Select a series of angular velocities and use a self-written program to generate a series of input files for side slip analysis; 5.7) Submit for batch solution, and use self-written program to automatically extract and post-process the results.

2. The finite element simulation method for tire side slip composite slip characteristics according to claim 1, characterized in that: In step 1), the tire material distribution map is finely meshed to distinguish various tire components.

3. The finite element simulation method for tire side slip composite slip characteristics according to claim 1, characterized in that: In step 2.1), the rebar model is used for all skeleton materials, in which the belt is added with the lift equation, and the elongation and belt radius are calculated by designing the belt drum diameter and the design outer diameter.

4. The finite element simulation method for tire side slip composite slip characteristics according to claim 1, characterized in that: In step 5.3), add a friction model between the road surface and the tire. The friction model includes slip velocity and contact pressure parameters, and sets the friction coefficient between the tire and the rim to a range between 0.1 and 0.

5.

5. The finite element simulation method for tire side slip composite slip characteristics according to claim 1, characterized in that: In step 5.4), the calculation time range of uniform rolling analysis is set to between 0.05s and 0.2s.

6. The finite element simulation method for tire side slip composite slip characteristics according to claim 1, characterized in that: In step 5.5), the calculation time of the lateral slip analysis step is set to t1 between 0.05s and 0.15s, and t2 between 0.05s and 0.5s. In the historical variable output, 4 variables of rim reference points RF1, RF2, RM3, and RF3 are set. RF3 is used to refer to whether the load is stable during the calculation process. The maximum setting of t is 0.0025s, that is, at least 400 points are output per second.

7. The finite element simulation method for tire side slip composite slip characteristics according to claim 1, characterized in that: In step 5.6), the selected slip rates must include the maximum and minimum slip rates, i.e. the critical values, and the rest are selected according to the actual situation. Each slip rate corresponds to a calculation file.

8. The finite element simulation method for tire side slip composite slip characteristics according to claim 1, characterized in that: In step 5.7), extract data from each calculation result file and extract the time history of the side slip analysis step as the last t L s data, each variable has t L / t data points, and the corresponding variable value under the slip rate is obtained by averaging these data points. The variable values ​​include RF1, RF2, RM3, RF3, etc. The points are plotted with the slip rate as the horizontal coordinate and the variable value RF1 as the vertical coordinate, and a scatter plot of the longitudinal force changing with the slip rate can be obtained, or a straight line or curve can be connected in order of slip rate from small to large to obtain a curve plot of the longitudinal force changing with the slip rate. Similarly, a scatter plot or curve plot of the variable values ​​​​such as RF2 and RM3 changing with the slip rate can be obtained.

9. A computer device comprising a memory, a processor and a computer program stored in the memory, characterized in that: The processor executes the computer program to implement the method according to any one of claims 1 to 8.

10. A computer-readable storage medium having a computer program or instruction stored thereon, characterized in that: When the computer program or instruction is executed by a processor, the method described in any one of claims 1 to 8 is implemented.

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