A simplified method for evaluating the fatigue performance of tire rubber, its application, and computer software products.

Abstract

This invention relates to the field of tire simulation design technology, and more particularly to a simplified method, application, and computer software product for evaluating the fatigue performance of tire rubber. The method of this invention can process calculation results based on simple tire numerical simulation, evaluate tire fatigue performance using the cumulative maximum shape energy index, accurately predict fatigue failure locations, and be used to evaluate tire fatigue performance, providing a basis for tire design. Through the above calculation process, the location of the tire most prone to fatigue failure can be obtained. By comparing multiple schemes, the optimal scheme can be determined, providing guidance for tire design and scheme evaluation.

Description

Technical Field

[0001] This invention relates to the field of tire simulation design technology, and in particular to a simple method for evaluating tire rubber fatigue performance, its application, and computer software products. Background Technology

[0002] Tires are organically composed of materials such as rubber, steel wire, and nylon, with rubber being the weakest component. During vehicle operation, tires undergo repeated deformation, causing cyclic stress and strain in the rubber material. After prolonged driving, fatigue cracks can develop in the rubber material, leading to tire failure. Premature tire failure wastes resources and increases the burden on car owners. Therefore, it is essential to avoid premature tire fatigue failure as much as possible. This requires comparing multiple options during structural design and improvement processes to select the tire with superior performance.

[0003] Currently, the main methods for evaluating tire fatigue performance are experimental methods and numerical simulation methods. Experimental methods suffer from drawbacks such as long cycles and high costs; therefore, numerical simulation methods are generally used to evaluate tire performance. Although dedicated numerical simulation methods for rubber material fatigue are becoming increasingly mature, such as the Endurica software, they require extensive unconventional testing of the analyzed rubber material. This is not only technically challenging but also time-consuming and labor-intensive, requiring re-measuring of rubber material parameters when analyzing different tires. The pursuit of tire numerical simulation technology is to obtain fatigue performance information of rubber materials from simple tire numerical simulation results. Simple tire numerical simulation methods are generally based on the finite element method. Based on the basic theory of solid mechanics, a computer is used to calculate a numerical model of the tire, which can quickly obtain the stress and strain states of the tire under different operating conditions. However, the calculation results contain dozens of variables, such as stress in six directions, strain in six directions, energy, and energy density. Which variables can accurately characterize the fatigue performance of tire rubber materials is a difficult problem that plagues tire structural analysis engineers.

[0004] Rubber materials exhibit different fatigue properties under different stress states. Generally, they have a longer fatigue life under tension and compression, but a shorter fatigue life under shear conditions. However, there are various indices for shear strain. Through long-term research, the inventors discovered that a single shear strain index cannot accurately characterize the location of tire failure and fatigue performance. Summary of the Invention

[0005] To address the aforementioned technical problems, the present invention aims to propose a simple method for evaluating the fatigue performance of tire rubber. Based on a simple numerical simulation of tires, the calculation results are processed, and the cumulative maximum shape energy index is used to evaluate the fatigue performance of the tire. This method can accurately predict the fatigue failure location and is used to evaluate the fatigue performance of the tire.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A simplified method for evaluating the fatigue performance of tire rubber, comprising the following steps:

[0008] The first step is to establish a finite element model of the tire and perform load analysis:

[0009] 1.1) Mesh the material distribution map of the tire, assign material properties, apply the rated inflation pressure, and perform a two-dimensional axisymmetric inflation analysis;

[0010] 1.2) Based on the inflation analysis, an axisymmetric model with N cutoffs is generated by rotation. The angles of the N cutoffs can be different. The element number offset between adjacent cutoffs is k, and k needs to be greater than the total number of elements m in the two-dimensional axisymmetric model of the tire.

[0011] 1.3) Apply the rated load to the tires and perform tire load analysis;

[0012] The second step is to perform steady-state rolling analysis on the tire:

[0013] Based on the load analysis in the first step, a rotational angular velocity and a translational velocity are applied to the tire and rim. The translational velocity is determined based on the actual rolling of the tire. The standard for determining the rotational angular velocity is that the frictional force between the tire and the road surface along the direction of the translational velocity is less than 10N.

[0014] The third step is to extract the principal stresses of all rubber material elements in the tire model, namely σ1, σ2, and σ3. By convention, the signs represent the magnitude relationship as σ1>σ2>σ3. The distortion energy density of the elements is then calculated using the following formula:

[0015]

[0016] The fourth step is to extract the distortion energy density sequence of the elements in the tire model that occupy the same position as element numbered i in the two-dimensional axisymmetric analysis, denoted as . Then, calculate the incremental accumulation of the sequence, W. i for:

[0017]

[0018] By comparing the W of each unit i The cell containing the highest distortion energy density is the location where the tire is most likely to fail first.

[0019] Preferably, in step 1.1), the tire material distribution map is meshed into triangular or quadrilateral elements, the skeleton material is divided into 2-node one-dimensional elements, and material properties are assigned to each component material to establish a tire finite element model. A pressure of 0.25 MPa is applied to the inner surface of the tire inner liner, and inflation analysis is performed using Abaqus software.

[0020] A simplified method for evaluating the fatigue performance of tire rubber according to claim 1 or 2, characterized in that the material properties of each component are as follows:

[0021] Component Name Material modulus (MPa) Poisson's ratio <![CDATA[Density (10 -9 t / mm 3 )]]> tanδ fetus 2 0.49 1 0.1 Protective Gel 3 0.49 1 0.12 Inner lining 2 0.49 1 0.14 Base adhesive 3.5 0.49 1 0.08 Crown layer 3 0.49 1 0.13 Second belt layer 3 0.49 1 0.12 First belt layer 3 0.49 1 0.12 tread 4 0.49 1 0.16 tire sidewall 3 0.49 1 0.17 Triangle rubber 8 0.49 1 0.15 wire ring 21000 0.3 7 0.0 Coronal stratigraphy 1000 0.3 1.2 0.0 fetal skeleton 2000 0.3 1.2 0.0 Belt layer skeleton 100000 0.3 6 0.0

[0022] Preferably, in step 1.2), based on the two-dimensional inflation analysis, the tire cross-section is rotated 360 degrees and divided into circumferential sections, with 90 sections in the circumference. The section angle in the tire contact area is 2 degrees, and the section angle away from the contact area is 5 degrees. The unit number offset between adjacent sections in the transition area is k=4000, which is greater than the total number of units m=1931 in the two-dimensional axisymmetric model of the tire.

[0023] Preferably, in step 1.3), the tire rim is fixed, a load of 5881N is applied to the road surface, causing the road surface to move in the direction of the rim, and load analysis is performed.

[0024] Preferably, the translational speed in step two is determined to be 80 km / h based on the actual rolling of the tire, and the standard for determining the rotational angular velocity is that the frictional force between the tire and the road surface along the direction of the translational speed is less than 10 N, the angular velocity is 70.523 rad / s, and the frictional force is 8.2 N.

[0025] Furthermore, the present invention also provides the application of the aforementioned simplified evaluation method for tire rubber fatigue performance in tire simulation analysis.

[0026] Furthermore, the present invention also discloses a computer device, including a memory, a processor, and a computer program stored in the memory, wherein the processor executes the computer program to implement the method.

[0027] Furthermore, the present invention also discloses a computer-readable storage medium having a computer program or instructions stored thereon, which, when executed by a processor, implement the method.

[0028] Furthermore, the present invention also discloses a computer program product, including a computer program or instructions that, when executed by a processor, implement the method.

[0029] This invention, by employing the aforementioned technical solution, can process calculation results based on simple tire numerical simulation, evaluate tire fatigue performance using the cumulative maximum shape energy index, accurately predict fatigue failure locations, and use this information to assess tire fatigue performance, providing a basis for tire design. The calculation process yields the location most prone to fatigue failure, and by comparing multiple solutions, the optimal solution can be selected, providing guidance for tire design and solution evaluation. Attached Figure Description

[0030] Figure 1 This is a material distribution diagram for a 21550R15 tire.

[0031] Figure 2 For 21550R15 tire cross-section grid and material components.

[0032] Figure 3 The results of inflating a 21550R15 tire show deformation.

[0033] Figure 4 A three-dimensional axisymmetric model and truncation of a 21550R15 tire.

[0034] Figure 5 The static load deformation of a 21550R15 tire.

[0035] Figure 6 The diagram shows the angular velocity and translational velocity directions for a 21550R15 tire during steady-state calculations.

[0036] Figure 7 This is a cloud map of the W value for a 21550R15 tire unit.

[0037] Figure 8 The image shows the fatigue failure of a 21550R15 tire tested in an experiment. Detailed Implementation

[0038] The present invention will be further described in detail below with reference to the accompanying drawings: This embodiment is implemented under the premise of the technical solution of the present invention, and detailed implementation methods are given, but the protection scope of the present invention is not limited to the following embodiments.

[0039] Taking 21550R15 tires as an example:

[0040] The first step is to analyze the tire material distribution map ( Figure 1 ) Perform mesh generation, dividing the data into triangular or quadrilateral units ( Figure 2 The skeleton material was divided into 2-node one-dimensional elements, and material properties were assigned to each component (Table 1). A finite element model of the tire was established, and an air pressure of 0.25 MPa was applied to the inner surface of the tire inner liner. Inflation analysis was performed using Abaqus software, and the results are as follows. Figure 3As shown. Based on the two-dimensional inflation analysis, the tire cross-section is rotated 360 degrees and divided circumferentially, resulting in 90 segments around the circumference. Figure 4 The cutoff angle is 2 degrees in the tire contact area and 5 degrees in the area away from the contact area. The cell number offset between adjacent cutoffs in the transition area is k= 4000 The number of elements is greater than the total number of elements m=1931 in the two-dimensional axisymmetric model of the tire. The tire rim is fixed, and a load of 5881N is applied to the road surface, causing the road surface to move towards the rim. Load analysis is then performed. Figure 5 ).

[0041] Table 1. Material properties assigned to each component.

[0042] Component Name Material modulus (MPa) Poisson's ratio <![CDATA[Density (10 -9 t / mm 3 )]]> tanδ fetus 2 0.49 1 0.1 Protective Gel 3 0.49 1 0.12 Inner lining 2 0.49 1 0.14 Base adhesive 3.5 0.49 1 0.08 Crown layer 3 0.49 1 0.13 Second belt layer 3 0.49 1 0.12 First belt layer 3 0.49 1 0.12 tread 4 0.49 1 0.16 tire sidewall 3 0.49 1 0.17 Triangle rubber 8 0.49 1 0.15 wire ring 21000 0.3 7 0.0 Coronal stratigraphy 1000 0.3 1.2 0.0 fetal skeleton 2000 0.3 1.2 0.0 Belt layer skeleton 100000 0.3 6 0.0

[0043] The second step is to perform a steady-state rolling analysis of the tire. Based on the load analysis in the first step, rotational angular velocity and translational velocity are applied to the tire and rim. Figure 6 The translational speed was determined to be 80 km / h based on the actual rolling of the tire. The standard for determining the rotational angular velocity was that the frictional force between the tire and the road surface along the direction of the translational speed was less than 10 N. After 5 attempts, the final angular velocity was determined to be 70.523 rad / s, at which point the frictional force was 8.2 N, which was less than 10 N.

[0044] The third step is to extract the principal stresses of all rubber material elements in the tire model, namely σ1, σ2, and σ3. The symbols are used to represent the magnitude relationship as σ1>σ2>σ3, as shown in Table 2.

[0045] Table 2

[0046] Unit Number <![CDATA[σ1]]> <![CDATA[σ2]]> <![CDATA[σ3]]> 2 -2.30E-02 -4.92E-03 2.88E-02 7 -1.77E-02 -3.03E-03 2.14E-02 29 -6.56E-03 1.64E-03 5.11E-03 32 -1.00E-02 -6.07E-03 1.62E-02 65 -4.35E-03 4.14E-05 4.47E-03 68 -6.63E-03 1.67E-03 5.17E-03 95 -5.23E-03 4.23E-04 4.97E-03 100 -4.35E-03 3.92E-05 4.48E-03 137 -5.23E-03 4.23E-04 4.97E-03 149 -1.00E-02 -6.08E-03 1.62E-02 152 -6.56E-03 1.64E-03 5.11E-03 184 -6.63E-03 1.67E-03 5.17E-03 192 -1.77E-02 -2.99E-03 2.14E-02 197 -2.29E-02 -4.86E-03 2.87E-02 258 -1.09E-02 8.27E-04 9.89E-03 259 -1.11E-02 4.20E-03 6.60E-03 287 -1.11E-02 4.21E-03 6.59E-03 288 -1.08E-02 8.26E-04 9.88E-03 897 -2.26E-02 7.13E-03 1.20E-02 902 -3.02E-02 1.25E-02 1.43E-02 987 -3.02E-02 1.25E-02 1.43E-02 992 -2.26E-02 7.13E-03 1.20E-02 1024 -1.83E-02 5.70E-03 9.44E-03 1064 -1.83E-02 5.70E-03 9.44E-03 1083 -0.113 3.37E-03 0.1071

[0047] The distortion energy density of the element is calculated using the following formula:

[0048]

[0049] Taking Unit 2 as an example:

[0050] σ1 = 0.028772, σ2 = -0.0049216, σ3 = -0.022953, calculate w as 0.0020679328459599997.

[0051] The fourth step is to extract the distortion energy density sequence of the elements in the tire model that occupy the same position as element numbered i in the two-dimensional axisymmetric analysis (as shown in Table 3), denoted as... .

[0052] Table 3

[0053] Unit Number w Unit Number w Unit Number w 3 0.002394 120003 0.006262 240003 0.006018 4003 0.002394 124003 0.006548 244003 0.005587 8003 0.002398 128003 0.006805 248003 0.005196 12003 0.002406 132003 0.007091 252003 0.00486 16003 0.002418 136003 0.007421 256003 0.004568 20003 0.002435 140003 0.007836 260003 0.004313 24003 0.002457 144003 0.008318 264003 0.004088 28003 0.002486 148003 0.008824 268003 0.003888 32003 0.002518 152003 0.009332 272003 0.00371 36003 0.002554 156003 0.00983 276003 0.003551 40003 0.002595 160003 0.01029 280003 0.003411 44003 0.002644 164003 0.01069 284003 0.003286 48003 0.002704 168003 0.01101 288003 0.003176 52003 0.002777 172003 0.01122 292003 0.003086 56003 0.002873 176003 0.01134 296003 0.003001 60003 0.002975 180003 0.01135 300003 0.002897 64003 0.003059 184003 0.01124 304003 0.002799 68003 0.003145 188003 0.01104 308003 0.002725 72003 0.003252 192003 0.01074 312003 0.002665 76003 0.003372 196003 0.01035 316003 0.002616 80003 0.003507 200003 0.009899 320003 0.002575 84003 0.003659 204003 0.009414 324003 0.002539 88003 0.003827 208003 0.00892 328003 0.002507 92003 0.004016 212003 0.00843 332003 0.002477 96003 0.004227 216003 0.00796 336003 0.002452 100003 0.004468 220003 0.007549 340003 0.002432 104003 0.004745 224003 0.007221 344003 0.002417 108003 0.005066 228003 0.006942 348003 0.002406 112003 0.005447 232003 0.00669 352003 0.002399 116003 0.005872 236003 0.006409 356003 0.002395

[0054] Then, the increment accumulation of the sequence is calculated. W i for:

[0055]

[0056] According to Table 2, W3 = 0.020306 is calculated. The program then calculates the W values ​​for all units. i The values ​​are displayed graphically, and the results are as follows: Figure 7 As shown in the figure, the maximum value of W is located at the tire bead, which is consistent with the experimental test results (e.g., ...). Figure 8 (This is consistent with the previous statement.)

[0057] The above calculation process can accurately determine the most dangerous location of tire fatigue failure. The simulation model of the entire calculation process only requires the input of material modulus and Poisson's ratio parameters, and the data processing time is about 1 minute. However, when using fatigue analysis software, the simulation model also requires the input of the cracking energy density values ​​of each material, and the calculation time is about 30 minutes. This proves the effectiveness and innovation of the present invention.

[0058] The foregoing description of embodiments of the present invention, through which those skilled in the art are able to implement or use the present invention, will be readily apparent to those skilled in the art. Various modifications to these embodiments will be readily apparent to those skilled in the art. The general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novelty disclosed herein.

Claims

1. A simplified method for evaluating the fatigue performance of tire rubber, characterized in that, The method includes the following steps: The first step is to establish a finite element model of the tire and perform load analysis: 1.1) Mesh the material distribution map of the tire, assign material properties, apply the rated inflation pressure, and perform a two-dimensional axisymmetric inflation analysis; 1.2) Based on the two-dimensional axisymmetric inflation analysis, a two-dimensional axisymmetric tire model with N truncated sections is generated by rotation. The angles of the N truncated sections are all different, and the element number offset between adjacent sections is [value missing]. k , k It needs to be greater than the total number of elements m in the two-dimensional axisymmetric model of the tire; 1.3) Apply the rated load to the tires and perform tire load analysis; The second step is to perform steady-state rolling analysis on the tire: Based on the load analysis in the first step, a rotational angular velocity and a translational velocity are applied to the tire and rim. The translational velocity is determined based on the actual rolling of the tire. The standard for determining the rotational angular velocity is that the frictional force between the tire and the road surface along the direction of the translational velocity is less than 10N. The third step is to extract the principal stresses of all rubber material elements in the tire finite element model, namely σ1, σ2, and σ3. By convention, the signs represent the magnitude relationship as σ1>σ2>σ3. The distortion energy density of the elements is then calculated using the following formula: ； The fourth step is to extract the distortion energy density sequence of the elements in the tire finite element model that occupy the same position as element numbered i in the two-dimensional axisymmetric inflation analysis, denoted as . , 0≤j≤N; then, calculate the increment accumulation of the sequence, W i for: ； By comparing the W of each unit i The cell containing the highest distortion energy density is the location where the tire is most likely to fail first.

2. The simplified evaluation method for tire rubber fatigue performance according to claim 1, characterized in that, Step 1.1) Mesh the tire material distribution map into triangular or quadrilateral elements, divide the skeleton material into 2-node one-dimensional elements, assign material properties to each component material to establish a tire finite element model, apply 0.25MPa air pressure to the inner surface of the tire inner liner, and perform inflation analysis using Abaqus software.

3. A simplified method for evaluating the fatigue performance of tire rubber according to claim 1 or 2, characterized in that, The material properties assigned to each component are as follows: 。 4. The simplified evaluation method for tire rubber fatigue performance according to claim 1, characterized in that, Step 1.2) Based on the two-dimensional axisymmetric inflation analysis, the tire section is rotated 360 degrees and divided into sections in the circumference. The circumference is divided into 90 sections. The section angle in the tire contact area is 2 degrees and the section angle away from the contact area is 5 degrees. The element number offset between adjacent sections in the transition area is k=4000, which is greater than the total number of elements m=1931 in the two-dimensional axisymmetric tire model.

5. A simplified method for evaluating the fatigue performance of tire rubber according to claim 1, characterized in that, Step 1.3) Fix the tire rim, apply a load of 5881N to the road surface, and move the road surface towards the rim to perform load analysis.

6. The simplified evaluation method for tire rubber fatigue performance according to claim 1, characterized in that, In the second step, the translational speed is determined to be 80 km / h based on the actual rolling of the tire, the angular velocity is 70.523 rad / s, and the friction force is 8.2 N.

7. The application of a simplified evaluation method for tire rubber fatigue performance according to any one of claims 1-6 in tire simulation analysis.

8. 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 1-6.

9. A computer-readable storage medium having a computer program or instructions stored thereon, characterized in that, When the computer program or instructions are executed by a processor, they implement the method described in any one of claims 1-6.

10. A computer program product, comprising a computer program or instructions, characterized in that, When the computer program or instructions are executed by a processor, they implement the method described in any one of claims 1-6.

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