Method for improving simulation convergence in inflation process of air spring

Abstract

The invention belongs to the field of simulation of air springs, and discloses a method for improving simulation convergence of an air spring in an inflation process, which provides enough constraint for expansion of an air bag component and improves convergence of the model by establishing an air spring model and a cylinder component and combining limitation of boundary conditions. And a simulation result of the air spring can be obtained more quickly. According to the method for improving the simulation convergence in the inflation process of the air spring, the convergence of the model is improved, and the problem that simulation convergence fails due to the fact that an existing air bag component lacks constraint in the expansion process and is prone to displacement instability is solved.

Description

Technical Field

[0001] This invention relates to a method for improving the convergence of air spring inflation process simulation, belonging to the field of air spring simulation. Background Technology

[0002] Air springs are widely used in high-speed rail, subways, and other applications where passenger comfort is a primary consideration, and their application is expanding into the high-end automotive sector. In the early design phase of elastic components, finite element method (FEM) simulation is typically used to evaluate the product's stiffness performance. However, due to the large deformation characteristics of air springs, simulations face significant convergence challenges, making it difficult to reach the desired stiffness calculation range.

[0003] A search revealed that CN202310602445.6 provides a method for simulating the dynamics of automotive air suspension, aiming to address the problem of insufficient accuracy in existing simulation results. On one hand, by recording the airbag stiffness as a stiffness array K, and interpolating the air spring stiffness curve based on the air suspension's attitude height and preload, the dynamic characteristics of air spring stiffness changes are simulated with less measurement data, improving simulation efficiency while meeting analysis accuracy requirements. On the other hand, by using the angle A between the vehicle body and suspension links in the model to detect and judge the current suspension attitude, suspension attitude feedback is achieved. Under different suspension loads, the working height of the air spring can be automatically adjusted according to the suspension attitude control requirements. The simulation model conforms to the actual working principle of the air spring, improving the accuracy of air suspension dynamics simulation.

[0004] While there are numerous simulations of air springs in existing technologies, methods to improve simulation convergence are not addressed. Currently, the simulation loading method used for stiffness calculations of air springs involves applying pressure to the airbag components. Because this method relies on pneumatic loading, the airbag components lack constraints during expansion, easily leading to displacement instability and causing simulation convergence failure.

[0005] Therefore, inventing a method to improve the convergence of air spring simulation and obtain simulation results of air springs more quickly has important practical significance and economic value. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention proposes a method to improve the convergence of air spring inflation simulation. By establishing an external cylindrical component and changing the boundary condition settings of the air spring simulation, sufficient constraints are provided for the expansion of the airbag component, thereby improving the model's convergence and obtaining the simulation results of the air spring more quickly.

[0007] The technical means adopted by the present invention to solve the above problems are as follows: A method for improving the convergence of air spring inflation simulation is disclosed. By establishing an air spring model and a cylindrical component, and combining the boundary conditions, sufficient constraints are provided for the expansion of the airbag component, thereby improving the convergence of the model and obtaining the simulation results of the air spring more quickly.

[0008] Further, the establishment of the air spring model specifically includes the following steps: S11. Establishing basic spring components, including airbag components, cord components, and upper and lower cover plate components; S12. Embedding the cord components into the rubber part of the airbag components to simulate the airbag components of an actual air spring; S13. Simulating the gas part of the air spring through a fluid cavity; S14. Binding and connecting different components to simulate adhesion.

[0009] Further, step S12 specifically involves using the SFMAX1 element type to simulate the cord component and the C3X4H element type to simulate the rubber part of the airbag component in the mesh setting module of the simulation software.

[0010] Furthermore, step S13 specifically involves setting the reference point at the center of the airbag component based on the symmetry of the internal pressure distribution of the airbag component; in the simulation software, establishing fluid cavity interaction between the reference point and the inner surface of the cavity, and applying internal pressure and displacement constraints to the airbag component through the reference point.

[0011] Furthermore, the cylindrical component is specifically constructed by creating a hollow cylindrical component on the outer surface of the airbag component, with the inner diameter of the cylindrical component being consistent with the outer diameter of the airbag component; the height of the cylindrical component is set to 1.2 to 1.5 times the height of the airbag component to ensure that the deformation of the airbag component during the expansion process never exceeds that of the cylindrical component.

[0012] Furthermore, the boundary conditions are specifically defined as follows: a pressure load is applied to the airbag component, while the contact between the airbag component and the cylindrical component is eliminated, and the curve of the expansion displacement-calculation time of the airbag component in the free state is calculated and output.

[0013] Due to simulation convergence issues, the calculation usually stops midway due to non-convergence. In this case, the curve can be extrapolated along the tangent at the endpoint to the point in time when the calculation is completed, which can then be used for subsequent estimation of the amplitude curve.

[0014] Furthermore, the simulation also includes applying a radially outward displacement load to the cylindrical component and adding an amplitude curve. The amplitude curve is a function of amplitude and time, including linear and sinusoidal functions, and its product with the displacement load is the actual displacement of the cylindrical component. In this way, during the simulation, the expansion displacement of the cylindrical component is always less than the expansion displacement of the airbag component in its free state, and the two are always in contact, thus providing sufficient constraint to the airbag component.

[0015] Furthermore, after the airbag component expands to an equilibrium state, the cylindrical component continues to expand outward to a certain distance, which can be set to 1.1 to 1.2 times the maximum expansion radius of the airbag component. This avoids contact between the cylindrical component and the airbag component during subsequent stiffness simulation, thus preventing the simulation results from being affected.

[0016] Compared with the prior art, the beneficial effects of the present invention are: 1. The method of improving the convergence of the air spring inflation process simulation of the present invention combines the establishment of the air spring model with the establishment of the external cylindrical component, thereby changing the boundary condition settings of the air spring simulation and providing sufficient constraints for the expansion of the airbag component.

[0017] 2. The method of improving the simulation convergence of the air spring inflation process of the present invention improves the convergence of the model and solves the problem that the existing airbag components lack constraints during the expansion process, which easily leads to displacement instability and simulation convergence failure. The simulation results of the air spring can be obtained more quickly. Attached Figure Description

[0018] Figure 1 This is a model diagram of the air spring and cylindrical component in an embodiment of the present invention; Figure 2 This is a schematic diagram showing the contact between the air spring and the cylindrical component during the expansion process in an embodiment of the present invention; Figure 3 This is a simulation of the stiffness of the air spring in an embodiment of the present invention.

[0019] Among them, 1-airbag component, 2-upper and lower cover plate components, 3-cylinder component. Detailed Implementation

[0020] The present invention will be further described below with reference to the accompanying drawings. The drawings are for illustrative purposes only, representing schematic diagrams rather than actual physical objects, and should not be construed as limiting the scope of this patent. To better illustrate the embodiments of the present invention, some components in the drawings may be omitted, enlarged, or reduced, and do not represent the actual dimensions of the product. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings. Example 1

[0021] This embodiment presents a method for improving the convergence of air spring inflation simulation. By establishing an air spring model and a cylindrical component, and combining this with boundary condition constraints, sufficient constraints are provided for the expansion of the airbag component, thus improving the model's convergence and obtaining simulation results for the air spring more quickly. The method for setting simulation boundary conditions is improved, reducing simulation difficulty and increasing simulation efficiency. The implementation steps are as follows.

[0022] S1. Establish the air spring model: S11. Establish the basic components of the spring, specifically the basic components of the air spring such as airbag component 1, cord component, and upper and lower cover plate components 2; the top of the airbag component 1 is provided with an upper cover plate, such as... Figure 1 As shown.

[0023] S12. The actual air spring airbag component 1 is simulated by embedding the cord component into the rubber part of the airbag component 1 using the embedded method. The settings are as follows: ① In the mesh settings of the simulation software, the cord component is simulated using SFMAX1 element type, and the rubber part of the airbag component 1 is simulated using C3X4H element type. ② In the interaction settings of the simulation software, open the embedded region settings window, select the cord component in the embedded region, select the rubber part of the airbag component 1 in the host region, and then click OK.

[0024] S13. The gas component of the air spring is simulated using a fluid cavity, with the following settings: ① A reference point is established within the air spring cavity. Based on the symmetry of the internal pressure distribution of airbag component 1, the reference point is located at the center of the airbag component. ② In the simulation software, using the fluid cavity setting, an interaction is established between the reference point and the inner surface of the cavity, applying internal pressure, displacement, and other constraints to airbag component 1 through the reference point.

[0025] S14. Connect different components by binding. The upper and lower cover plate components 2 of the air spring and the airbag component 1 are usually bonded together with adhesive. Therefore, the binding relationship between the upper and lower cover plate components 2 and the airbag component 1 is established by using tie settings in the simulation software to simulate the bonding effect.

[0026] S2. Establishment of the cylindrical component: A hollow cylindrical component 3 is established on the outer surface of the airbag component 1, with the inner diameter of the cylindrical component matching the outer diameter of the airbag component 1. The height of the cylindrical component 3 can be set to 1.2 to 1.5 times the height of the airbag component 1, ensuring that the deformation of the airbag component 1 during expansion never exceeds that of the cylindrical component. A contact is established between the inner surface of the cylindrical component 3 and the outer surface of the airbag component.

[0027] S3. Apply boundary conditions: Apply a pressure load to airbag component 1, and simultaneously cancel the contact between airbag component 1 and cylindrical component 3. Calculate and output the curve of expansion displacement versus calculation time of airbag component 1 in free state. Due to simulation convergence issues, this calculation usually stops midway due to non-convergence. In this case, the curve can be extrapolated along the tangent at the endpoint to the time point when the calculation is completed, for subsequent estimation of the amplitude curve.

[0028] A radially outward displacement load is applied to cylindrical component 3, and an amplitude curve is added. The amplitude curve is a function of amplitude and time, including linear and sinusoidal functions, etc. Its product with the displacement load is the actual displacement of cylindrical component 3. The magnitude of the applied displacement and the type of amplitude curve are selected based on the curve form of the airbag component's expansion displacement-calculated time in its free state, ensuring that the actual displacement-time curve of cylindrical component 3 is always lower than the expansion displacement-calculated time curve of airbag component 1 in its free state. For example... Figure 2 As shown, during the simulation, the expansion displacement of the cylindrical component 3 is always less than the expansion displacement of the airbag component 1 in its free state, and the two are always in contact, thus providing sufficient constraint to the airbag component 1.

[0029] like Figure 3 As shown, after the airbag component 1 expands to the equilibrium state, the cylindrical component 3 continues to expand outward to a certain distance, which can be set to 1.1 times to 1.2 times the maximum expansion radius of the airbag component 1. In this embodiment, it is preferably 1.1 times to avoid the cylindrical component 3 from contacting the airbag component 1 during the subsequent stiffness simulation process, which would affect the simulation results.

[0030] The above embodiments are for illustrative purposes only and are not intended to limit the invention. Those skilled in the art can make various changes or modifications without departing from the spirit and scope of the invention. Therefore, all equivalent technical solutions should also fall within the protection scope of the invention, which should be defined by the claims.

Claims

1. A method for improving the convergence of an air spring inflation process simulation, characterized in that, By establishing an air spring model and a cylindrical component, and combining the constraints of boundary conditions, sufficient constraints are provided for the expansion of the airbag component, improving the convergence of the model and obtaining simulation results of the air spring more quickly.

2. The method for improving the simulation convergence of the air spring inflation process according to claim 1, characterized in that, The establishment of the air spring model specifically includes the following steps. S11. Establish basic spring components, including airbag components, cord components, and upper and lower cover plate components; S12. The cord component is embedded into the rubber part of the airbag component using an embedded method to simulate the actual air spring airbag component; S13. The gas portion of the air spring is simulated using a fluid cavity; S14. Bind and connect different components to simulate adhesion.

3. The method for improving the simulation convergence of the air spring inflation process according to claim 2, characterized in that, Step S12 specifically involves using the SFMAX1 element type to simulate the cord component and the C3X4H element type to simulate the rubber part of the airbag component in the mesh settings section of the simulation software.

4. The method for improving the simulation convergence of the air spring inflation process according to claim 2, characterized in that, Step S13 specifically involves setting the reference point at the center of the airbag component based on the symmetry of the internal pressure distribution of the airbag component.

5. The method for improving the simulation convergence of the air spring inflation process according to claim 1, characterized in that, Specifically, the cylindrical component is created by building a hollow cylindrical component on the outer surface of the airbag component, with the inner diameter of the cylindrical component being the same as the outer diameter of the airbag component.

6. The method for improving the simulation convergence of the air spring inflation process according to claim 5, characterized in that, The height of the cylindrical component is set to 1.2 to 1.5 times the height of the airbag component to ensure that the deformation of the airbag component during expansion does not exceed that of the cylindrical component.

7. The method for improving the simulation convergence of the air spring inflation process according to claim 1, characterized in that, Specifically, the boundary conditions are defined as follows: a pressure load is applied to the airbag component, while the contact between the airbag component and the cylindrical component is eliminated, and the curve of the expansion displacement-calculation time of the airbag component in the free state is calculated and output.

8. The method for improving the simulation convergence of the air spring inflation process according to claim 7, characterized in that, It also includes applying radially outward displacement loads to the cylindrical components and adding amplitude curves.

9. The method for improving the simulation convergence of the air spring inflation process according to claim 8, characterized in that, After the airbag component expands to an equilibrium state, the cylindrical component continues to expand outward, to 1.1 to 1.2 times the maximum expansion radius of the airbag component.

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