A finite element analysis method for reducing the risk of bead split of all-steel radial tire

Abstract

The application provides a finite element analysis method for reducing the risk of bead crack of a full steel radial tire. The method can simulate the heavy load driving and braking conditions of the tire in the tire design stage by using the finite element analysis software Abaqus. The circumferential shear force S23 of the bead part near the rim flange under the tire torsion state is analyzed. According to the maximum value of the absolute value of the circumferential shear force S23 and the minimum change range, the risk of bead crack is low. The design scheme with low risk of bead crack is screened out. Therefore, only the design scheme with low risk of bead crack needs to be produced into a physical tire. Whether the tire has the problem of bead crack is determined by testing, so that the design scheme for producing the physical tire for experimental testing can be reduced, the number of outdoor testing to determine whether the tire has the problem of bead crack can be reduced, the development cycle is shortened, and the development cost is reduced.

Description

Technical Field

[0001] This invention relates to the risk analysis of bead cracks in all-steel radial tires, and more particularly to a finite element analysis method for reducing the risk of bead cracks in all-steel radial tires. Background Technology

[0002] With the continuous changes in the domestic mining market demand, OEMs are constantly updating and upgrading their models, moving towards larger sizes and increasing vehicle rated loads. In addition, the use of all-steel radial tires in the market involves high air pressure and high load, resulting in large deformation of the tire bead area. When the bead comes into contact with the rim, the driving and braking forces generated by the vehicle's driving and braking are transmitted to the tire through the rim. Due to the hysteresis effect, the rubber cannot respond immediately, which causes circumferential shear force at the contact point between the rim and the bead, resulting in oblique cracks in the bead area. Due to the periodic radial compression deformation, the oblique cracks gradually expand and eventually evolve into radial cracks. Currently, wide-body dump truck tires, large-specification rigid dump truck tires, giant tires, and port operation tires all have bead cracking problems.

[0003] Current technology mainly determines whether a tire has a bead crack problem through outdoor testing. Once a bead crack problem occurs, the design needs to be revised, a prototype tire needs to be produced, and outdoor testing needs to be conducted again. This process is repeated until the design does not have a bead crack problem. This method results in a lot of waste and a long production cycle. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a finite element analysis method for reducing the risk of bead cracking in all-steel radial tires. This invention allows for the selection of all-steel radial tire design schemes with a lower risk of bead cracking through finite element analysis. Therefore, only designs with lower bead cracking risk need to be manufactured into physical tires for testing, thus reducing the number of designs requiring physical tire production for experimental testing.

[0005] The objective of this invention is achieved through the following method: a finite element analysis method for reducing the risk of bead cracking in all-steel radial tires, comprising the following steps: (1) Establish a two-dimensional pneumatic tire simulation model to simulate the tire inflation and assembly process; (2) Establish a three-dimensional static loading simulation model to simulate the static loading process of the tire; (3) Establish a three-dimensional torsional loading simulation model to simulate the driving and braking process under heavy load; (4) Obtain the circumferential shear force S23 at the bead area near the rim flange under the torsional state of the tire; (5) Compare the circumferential shear force S23 of different design schemes of tires of the same specification. The design scheme with the largest absolute value of circumferential shear force S23 and the smallest variation range has a lower risk of bead cracking. Select the design scheme with a lower risk of bead cracking. (6) Produce physical tires for the design scheme with low risk of bead cracking, and then conduct durability tests. If no bead cracking occurs, select the design scheme; if bead cracking occurs, modify the design scheme and repeat the above five steps until a design scheme without bead cracking is found.

[0006] In step (4), the radial force S11 and circumferential shear force S23 of the bead portion near the rim flange under the torsional state of the tire are obtained; in step (5), the radial force S11 and circumferential shear force S23 of different design schemes of the same specification tire are compared. The design scheme with the smallest absolute value of circumferential shear force S23 and the smallest variation range, and the smallest absolute value of radial force S11 and the smallest variation range, has a lower risk of bead cracking. The design scheme with a lower risk of bead cracking is selected.

[0007] The establishment of the two-dimensional pneumatic tire simulation model in step (1) includes rim modeling (analytical rigid body type), rubber component modeling (CGAX4H / CGAX3H element type), reinforcement modeling (SFGMAX1 element type), defining the material constitutive model (Mooney-Rivlin hyperelastic constitutive model for rubber elements, Marlow model for reinforcement elements), defining cross-sectional properties (uniform solid cross-sectional properties for rubber components, shell cross-sectional properties for reinforcement elements), defining contact properties (general surface-to-surface contact between rim and bead), defining constraints (embedded constraints between rubber elements and reinforcement elements), defining analysis steps (nonlinear static general analysis for rim assembly and inflation), defining boundary conditions and loads (fixing all degrees of freedom except axial direction for rim), and applying a uniformly distributed pressure load to the inner surface of the tire.

[0008] In step (2), the establishment of the three-dimensional static loading simulation model includes generating a three-dimensional model by rotating a two-dimensional axisymmetric section around a rotation axis, specifying the rotation angle, number of elements, element offset ratio, and element type for each segment along the circumference, transmitting the analysis results of the two-dimensional axisymmetric model to the three-dimensional model, modeling the road surface, using the analytical rigid body type, defining contact properties, using general surface-to-surface contact for the road surface and tread, defining the analysis step, using nonlinear static general analysis for static loading, defining boundary conditions and loads, fixing all degrees of freedom for the rim, fixing all degrees of freedom for the road surface except the normal direction, and applying loads to the normal degree of freedom of the road surface.

[0009] In step (3), the establishment of the three-dimensional torsional loading simulation model includes applying boundary conditions and loads. Based on the three-dimensional static loading simulation results in step (2), a torsional load simulating the driving and braking states of the tire is applied. The torsional load is applied symmetrically to the reference points of the left and right rims, and the rotation angle is set to 0.0873~0.3491 rad. The remaining boundary conditions and loads are consistent with those in step (2).

[0010] In step (4), the radial force S11 and the circumferential shear force S23 are used. The circumferential shear force S23 is the evaluation index of the bead oblique crack. Because from the three-dimensional torsional loading simulation results in step (3), the circumferential shear force S23 on the bead near the rim corresponds to the circumferential oblique crack that occurs during the actual use of the tire. The radial force S11 is the evaluation of the bead radial crack. Because when there is a small circumferential crack on the bead near the rim, the radial force S11 on the bead will promote the crack to expand and eventually form a radial crack.

[0011] In step (6), if no bead crack occurs, the design specifications for radial force S11 and circumferential shear force S23 in the design process of this type of product are output. The design specifications for radial force S11 and circumferential shear force S23 refer to the fact that the maximum value (absolute value) of S11 and S23, and the range of variation, should be less than or equal to the values ​​of S11 and S23 in the design scheme where no bead crack occurred. That is, the maximum absolute value of radial force S11 and circumferential shear force S23 in the same type of product, and the range of variation, should be less than the values ​​of S11 and S23 in this design scheme.

[0012] This invention provides a finite element analysis method to reduce the risk of bead cracking in all-steel radial tires. This method utilizes the finite element analysis software Abaqus to simulate heavy-load driving and braking conditions during the tire design phase. By analyzing the circumferential shear force S23 near the rim flange of the tire under torsional conditions, the method identifies designs with lower bead cracking risk based on the maximum absolute value and the smallest variation range of the circumferential shear force S23. This allows for the selection of design schemes with lower bead cracking risk, enabling the production of only the lower-risk design schemes into physical tires for testing to determine if bead cracking occurs. This reduces the number of designs requiring physical tire production and testing, decreases the frequency of outdoor testing to determine bead cracking, shortens the development cycle, and lowers development costs. Attached Figure Description

[0013] Figure 1 This is a two-dimensional simulation model diagram of an inflatable tire according to Embodiment 1 of the present invention; Figure 2 This is a three-dimensional static loading simulation model diagram of Embodiment 1 disclosed in this invention; Figure 3 This is a three-dimensional torsional loading simulation model diagram of Embodiment 1 disclosed in this invention; Figure 4 This is a comparison diagram of the actual circumferential oblique crack in the tire bead and the circumferential shear force S23 at the bead location under simulated torsion state in Embodiment 1 of the present invention. Figure 5 This is a comparison diagram of the actual radial crack in the tire bead and the radial extrusion force S11 at the bead under simulated torsion conditions in Embodiment 1 of the present invention. Figure 6 A comparative analysis diagram of the circumferential shear force S23 around the tire bead near the rim flange in different design schemes of Embodiment 1 of the present invention; Figure 7 This is a comparative analysis diagram of the radial force S11 around the tire bead near the rim flange in different design schemes of Embodiment 1 of the present invention; Figure 8 These are the actual test results corresponding to design scheme 1 of Embodiment 1 disclosed in this invention; Figure 9 These are the actual test results corresponding to design scheme 2 of Embodiment 1 disclosed in this invention. Detailed Implementation

[0014] A finite element analysis method for reducing the risk of bead cracking in all-steel radial tires includes the following steps: (1) Establish a two-dimensional pneumatic tire simulation model to simulate the tire inflation and assembly process; (2) Establish a three-dimensional static loading simulation model to simulate the static loading process of the tire; (3) Establish a three-dimensional torsional loading simulation model to simulate the driving and braking process under heavy load; (4) Obtain the circumferential shear force S23 at the bead area near the rim flange under the torsional state of the tire; (5) Compare the circumferential shear force S23 of different design schemes of tires of the same specification. The design scheme with the largest absolute value of circumferential shear force S23 and the smallest variation range has a lower risk of bead cracking. Select the design scheme with a lower risk of bead cracking. (6) Produce physical tires for the design scheme with low risk of bead cracking, and then conduct durability tests. If no bead cracking occurs, select the design scheme; if bead cracking occurs, modify the design scheme and repeat the above five steps until a design scheme without bead cracking is found.

[0015] In step (4), the radial force S11 and circumferential shear force S23 of the bead portion near the rim flange under the torsional state of the tire are obtained; in step (5), the radial force S11 and circumferential shear force S23 of different design schemes of the same specification tire are compared. The design scheme with the smallest absolute value of circumferential shear force S23 and the smallest variation range, and the smallest absolute value of radial force S11 and the smallest variation range, has a lower risk of bead cracking. The design scheme with a lower risk of bead cracking is selected.

[0016] The establishment of the two-dimensional pneumatic tire simulation model in step (1) includes rim modeling (analytical rigid body type), rubber component modeling (CGAX4H / CGAX3H element type), reinforcement modeling (SFGMAX1 element type), defining the material constitutive model (Mooney-Rivlin hyperelastic constitutive model for rubber elements, Marlow model for reinforcement elements), defining cross-sectional properties (uniform solid cross-sectional properties for rubber components, shell cross-sectional properties for reinforcement elements), defining contact properties (general surface-to-surface contact between rim and bead), defining constraints (embedded constraints between rubber elements and reinforcement elements), defining analysis steps (nonlinear static general analysis for rim assembly and inflation), defining boundary conditions and loads (fixing all degrees of freedom except axial direction for rim), and applying a uniformly distributed pressure load to the inner surface of the tire.

[0017] In step (2), the establishment of the three-dimensional static loading simulation model includes rotating the two-dimensional axisymmetric section counterclockwise around the rotation axis to generate a three-dimensional model, and specifying the rotation angle, number of elements, element offset ratio and element type for each segment along the circumference. The analysis results of the two-dimensional axisymmetric model are transferred to the three-dimensional model. The road surface is modeled, the type is analytical rigid body, the contact properties are defined, the road surface and the tread adopt a general surface-to-surface contact, the analysis step is defined, the static loading adopts a nonlinear static general analysis, the boundary conditions and loads are defined, the rim is fixed with all degrees of freedom, the road surface is fixed with all degrees of freedom except the normal direction, and the load is applied to the normal degree of freedom of the road surface.

[0018] In step (3), the establishment of the three-dimensional torsional loading simulation model includes applying boundary conditions and loads. Based on the three-dimensional static loading simulation results in step (2), a torsional load simulating the driving and braking states of the tire is applied. The torsional load is applied symmetrically to the reference points of the left and right rims, and the rotation angle is set to 0.0873~0.3491 rad. The remaining boundary conditions and loads are consistent with those in step (2).

[0019] In step (4), the radial force S11 and the circumferential shear force S23 are used. The circumferential shear force S23 is the evaluation index of the bead oblique crack. Because from the three-dimensional torsional loading simulation results in step (3), the circumferential shear force S23 on the bead near the rim corresponds to the circumferential oblique crack that occurs during the actual use of the tire. The radial force S11 is the evaluation of the bead radial crack. Because when there is a small circumferential crack on the bead near the rim, the radial force S11 on the bead will promote the crack to expand and eventually form a radial crack.

[0020] In step (6), if no bead crack occurs, the design specifications for radial force S11 and circumferential shear force S23 in the design process of this type of product are output. The design specifications for radial force S11 and circumferential shear force S23 refer to the fact that the maximum value (absolute value) of S11 and S23 and the range of variation should be less than or equal to the values ​​of S11 and S23 in the design scheme without bead crack. That is, the maximum value and the range of variation of the absolute value of radial force S11 and circumferential shear force S23 in the same type of product should be less than the values ​​of S11 and S23 in this design scheme.

[0021] The present invention will now be described in detail with reference to specific embodiments. It should be noted that these embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Those skilled in the art can make some non-essential improvements and adjustments based on the above description of the present invention.

[0022] Using tires of specification 16.00R25, with a simulated inflation pressure of 1350 kPa and a simulated tire load of 14500 kg, a comparative analysis was conducted on the radial force S11 and circumferential shear force S23 at the bead region under torsional conditions for different design schemes of various tire specifications. The design scheme with a lower risk of bead cracking was selected, including the following steps: Mesh models were generated in Hypermesh software for different design schemes 1 and 2, and then the following operations were performed respectively. 1. Establish a two-dimensional simulation model of an inflatable tire. Figure 1The rim is designed as an analytical rigid body. The rubber element type is CGAX4H / CGAX3H, and the reinforcement element type is SFGMAX1. The rubber element adopts the Mooney-Rivlin hyperelastic constitutive model, and the reinforcement element adopts the Marlow model. The rubber component adopts the uniform solid section property, and the reinforcement adopts the shell section property. The rim and bead area adopt a general surface-to-surface contact. The rubber element and the reinforcement element adopt an embedded constraint. The rim assembly and inflation adopt a general nonlinear static analysis. The rim is fixed in all degrees of freedom except the Y direction. A uniform pressure load of 1350 kPa is applied to the inner surface of the tire.

[0023] 2. Establish a three-dimensional static loading simulation model Using the SYMMETRIC MODEL GENERATION command in Abaqus software, a three-dimensional model is generated by rotating a two-dimensional axisymmetric section counterclockwise around a rotation axis using the REVOLVE parameter, such as... Figure 2 As shown, the 60° sector area at the ground end is divided into 30 equal parts, with an element offset of 1.0 and a general element type. The 300° sector area at the ground end is also divided into 60 equal parts, with an element offset of 1.0 and a general element type. The SYMMETRIC RESULTS TRANSFER command is used to transfer the analysis results of the two-dimensional axisymmetric model to the three-dimensional model. The road surface is an analytical rigid body, and the road surface and tread are in general surface-to-surface contact. Static loading is performed using nonlinear static general analysis. The wheel rim is fixed with all degrees of freedom, and the road surface is fixed with all degrees of freedom except for the Z direction. A load of 142100N is applied to the road surface in the Z direction.

[0024] 3. Establish a three-dimensional torsional loading simulation model Based on the results of the three-dimensional static loading simulation in step 2, a torsional load simulating the tire's driving and braking states is applied. The torsional load is applied symmetrically to reference points on the left and right wheel rims, with the rotation direction around the Y-axis, as shown below. Figure 3 As shown, the rotation angle is set to 0.1745 rad, and the torsional load refers to the applied rotation angle of 0.1745 rad. The remaining boundary conditions and loads are consistent with step 2.

[0025] 4. Obtain the radial force S11 and circumferential shear force S23 at the tire bead area near the rim flange under tire torsion conditions. As shown in the figure Figure 4 and Figure 5 The stress cloud diagram on the right was obtained using Abaqus software.

[0026] 5. Compare the radial force S11 and circumferential shear force S23 of different design schemes. Comparing the circumferential shear force S23 and radial force S11 at the tire bead area near the rim flange of the two design schemes, from... Figure 6 It can be seen from the data that Design Scheme 2 (Plan 2) has the maximum absolute value of the circumferential shear force S23 and the smallest variation range, which is beneficial to reducing the generation of oblique cracks. Figure 7 It can be seen that the radial force S11 of design scheme 2 (Plan 2) has the maximum absolute value and the smallest variation range, which is conducive to reducing the generation of radial cracks. Overall, design scheme 2 has the lowest risk of generating bead cracks.

[0027] 6. Actual test results for different design schemes One 16.00R25 tire was manufactured according to each of the two design schemes in Example 1, and a durability test was conducted under an inflation pressure of 1350 kPa and a load of 14500 kg. The test results showed that the tire of Design Scheme 1 developed a bead crack problem. Figure 8 As shown, design scheme 2 did not experience bead cracking issues, as... Figure 9 As shown, this result is consistent with the analysis results of the two design schemes in step 5, that is, design scheme 2 has the lowest risk of producing bead cracks, proving that the finite element analysis method for reducing the risk of bead cracks in all-steel radial tires provided by this invention is effective.

[0028] 7. Design specifications for output radial force S11 and circumferential shear force S23 Since design scheme 2 in step 6 above did not produce bead cracks, design scheme 2 is selected. In order to avoid bead cracks in similar products, the maximum value and variation range of radial force S11 and circumferential shear force S23 should be less than the values ​​of S11 and S23 in scheme 2.

[0029] Theoretical analysis of the technical solution in this application: This application compares different design schemes and finds that, under tire torsion conditions, the radial force S11 and circumferential shear force S23 near the rim flange and bead area have the smallest absolute value and the smallest variation range of the circumferential shear force S23, which is beneficial to reducing the generation of oblique cracks. Similarly, the radial force S11 has the smallest absolute value and the smallest variation range, which is beneficial to reducing the generation of radial cracks. The possible reasons are: Figure 4 and Figure 5 This corresponds to a design scheme. Figure 4 and Figure 5 The image on the left shows the damage that occurred at different times of use. Figure 4 and Figure 5 The right side of the figure shows the result of the three-dimensional torsional loading simulation. It is a stress cloud diagram obtained by Abaqus software, which shows the circumferential shear force S23 and radial force S11 at the tire bead near the rim flange under the torsional state of the tire.

[0030] From the three-dimensional torsional loading simulation results in step (3), the circumferential shear force S23 experienced by the tire bead near the rim flange roughly corresponds to the circumferential oblique cracks that occur during actual tire use. Figure 4 As shown, the circumferential shear force S23 is therefore used as the evaluation index for oblique cracks in the bead. When there are small circumferential cracks in the bead area near the rim flange, the radial force S11 on the bead area will promote crack expansion, eventually forming a radial crack, such as... Figure 5 As shown, the radial force S11 is therefore used as the evaluation index for radial cracks in the tire bead. The correspondence between force and crack here refers to the fact that the direction of the corresponding force corresponds to the direction of the corresponding crack.

[0031] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. It should be noted that for those skilled in the art and any person skilled in the art, any equivalent substitutions or changes made to the technical solution and inventive concept of the present invention without departing from the overall concept of the present invention, as well as any changes and improvements made, should also be considered within the scope of protection of the present invention.

Claims

1. A finite element analysis method for reducing the risk of bead cracking in all-steel radial tires, characterized in that: Includes the following steps: (1) Establish a two-dimensional pneumatic tire simulation model to simulate the tire inflation and assembly process; (2) Establish a three-dimensional static loading simulation model to simulate the static loading process of the tire; (3) Establish a three-dimensional torsional loading simulation model to simulate the driving and braking process under heavy load; (4) Obtain the radial force S11 and circumferential shear force S23 at the bead area near the rim flange under the torsional state of the tire; (5) Compare the radial force S11 and circumferential shear force S23 of different design schemes for the same tire specification. The design scheme with the smallest absolute value of circumferential shear force S23 and the smallest absolute value of radial force S11 has a lower risk of bead cracking. Select the design scheme with a lower risk of bead cracking. (6) Produce physical tires for the design scheme with a low risk of bead cracking, and then conduct durability tests. If no bead cracking occurs, select the design scheme. If a bead tear occurs, modify the design and repeat the above five steps until a design without bead tears is found.

2. The finite element analysis method for reducing the risk of bead cracking in all-steel radial tires according to claim 1, characterized in that: The establishment of the two-dimensional pneumatic tire simulation model in step (1) includes rim modeling (analytical rigid body type), rubber component modeling (CGAX4H / CGAX3H element type), reinforcement modeling (SFGMAX1 element type), defining the material constitutive model (Mooney-Rivlin hyperelastic constitutive model for rubber elements, Marlow model for reinforcement elements), defining cross-sectional properties (uniform solid cross-sectional properties for rubber components, shell cross-sectional properties for reinforcement elements), defining contact properties (general surface-to-surface contact between rim and bead), defining constraints (embedded constraints between rubber elements and reinforcement elements), defining analysis steps (nonlinear static general analysis for rim assembly and inflation), defining boundary conditions and loads (fixing all degrees of freedom except axial direction for rim), and applying a uniformly distributed pressure load to the inner surface of the tire.

3. The finite element analysis method for reducing the risk of bead cracking in all-steel radial tires according to claim 1, characterized in that: In step (2), the establishment of the three-dimensional static loading simulation model includes generating a three-dimensional model by rotating a two-dimensional axisymmetric section around a rotation axis, specifying the rotation angle, number of elements, element offset ratio, and element type for each segment along the circumference, transmitting the analysis results of the two-dimensional axisymmetric model to the three-dimensional model, modeling the road surface, using the analytical rigid body type, defining contact properties, using general surface-to-surface contact for the road surface and tread, defining the analysis step, using nonlinear static general analysis for static loading, defining boundary conditions and loads, fixing all degrees of freedom for the rim, fixing all degrees of freedom for the road surface except the normal direction, and applying loads to the normal degree of freedom of the road surface.

4. The finite element analysis method for reducing the risk of bead cracking in all-steel radial tires according to claim 3, characterized in that: In step (3), the establishment of the three-dimensional torsional loading simulation model includes applying boundary conditions and loads. Based on the three-dimensional static loading simulation results in step (2), a torsional load simulating the driving and braking states of the tire is applied. The torsional load is applied symmetrically to the reference points of the left and right rims, and the rotation angle is set to 0.0873~0.3491 rad. The remaining boundary conditions and loads are consistent with those in step (2).

5. The finite element analysis method for reducing the risk of bead cracking in all-steel radial tires according to claim 1, characterized in that: In step (4), the radial force S11 and the circumferential shear force S23 are used. The circumferential shear force S23 is the evaluation index of the bead oblique crack. Because from the three-dimensional torsional loading simulation results in step (3), the circumferential shear force S23 on the bead near the rim corresponds to the circumferential oblique crack that occurs during the actual use of the tire. The radial force S11 is the evaluation of the bead radial crack. Because when there is a small circumferential crack on the bead near the rim, the radial force S11 on the bead will promote the crack to expand and eventually form a radial crack.

6. The finite element analysis method for reducing the risk of bead cracking in all-steel radial tires according to claim 1, characterized in that: In step (6), if no bead crack occurs, the design specifications for radial force S11 and circumferential shear force S23 in the design process of this type of product are output. The design specifications refer to the maximum absolute value of S11 and S23 and the range of change should be less than or equal to the values ​​of S11 and S23 in the design scheme where no bead crack occurs.

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