A method for modeling and simulating the durability of a spring perch of a macpherson suspension system

Abstract

The present application belongs to the technical field of Macpherson suspension system simulation, and particularly relates to a kind of Macpherson suspension system spring tray strength endurance modeling simulation method;Beam element topology structure equivalent Macpherson suspension system is established;Spring tray, spring upper and lower gasket, coil spring, spring upper support, shock absorber upper support structure are geometrically processed and meshed, and material and cross-section properties are assigned;Contact relationship is established;Secondly, Macpherson suspension system and vehicle body connection point are applied with six degrees of freedom, and up and down jump load is applied at the center of the wheel to calculate the stress nephogram of the spring tray in the up jump limit state and the down jump limit state;Finally, the stress of the spring tray in the up jump limit state and the down jump limit state is imported into FEMFAT software, and the specified stress cycle number is input to calculate the endurance damage value;The present application can accurately simulate the stress state of the spring lower tray and correctly guide the design of the spring tray.

Description

Technical Field

[0001] This invention belongs to the field of MacPherson suspension system simulation technology, specifically relating to a method for modeling and simulating the strength and durability of the spring tray in a MacPherson suspension system. Background Technology

[0002] MacPherson strut suspension damper system assembly model as follows Figure 1 As shown, its cross-sectional view is as follows Figure 2 As shown, the force distribution on the lower spring platen is explained as follows: When the wheel bounces upwards and downwards, the upper and lower sliding columns of the shock absorber will slide relative to each other. At the wheel's upward bounce limit, the lower sliding column of the shock absorber moves upwards relative to the upper sliding column. A spring platen is welded to the lower sliding column. The spring platen compresses the coil spring through the contact relationship with the lower spring pad. The upper end of the coil spring is pressed against the upper spring support through the upper pad, further transferring the load to the upper shock absorber support and the vehicle body. At the wheel's downward bounce limit, the coil spring is usually in a compressed state. The force transmission path is the same as when the wheel bounces upwards. The difference is that when the wheel bounces upwards, the load transmitted by the coil spring to the platen through the contact relationship with the lower spring pad is relatively large, and the tilt angle of the coil spring gradually increases as the wheel bounces upwards. When the wheel bounces downwards, the load applied by the coil spring to the lower spring platen is smaller, and the tilt angle of the spring is smaller. That is, the magnitude and direction of the force applied by the coil spring to the spring platen, as well as the contact area between the lower spring pad and the spring platen, are different in the two states of wheel bounce limit and downward bounce limit.

[0003] However, the current method for simulating the strength and durability of the spring tray in the MacPherson suspension system is to establish a mesh model of the lower column of the shock absorber and the spring tray, constrain the lower column of the shock absorber to degrees of freedom 1-6, and apply a uniform pressure load along the normal direction of the spring tray. The area where the uniform pressure load is applied is the contact area between the lower spring pad and the tray.

[0004] This simulation method overlooks several issues compared to reality, leading to inaccurate simulation results and an inability to properly guide the design of spring trays. Specific problems include:

[0005] 1. Because the springs in the MacPherson strut suspension system are tilted relative to the shock absorbers, the uniform load of the coil springs on the suspension tray is not along the normal direction of the tray.

[0006] 2. As the suspension system moves up and down, the contact area between the lower spring bushing and the spring tray changes;

[0007] 3. The 1-6 degrees of freedom of the lower column of the constraint damper are more rigid than the actual situation, and the simulation calculation results are too large. Summary of the Invention

[0008] To overcome the above problems, this invention provides a modeling and simulation method for the strength and durability of the spring tray in a MacPherson suspension system; it is a correct and reasonable modeling and loading method that can accurately simulate the stress state of the lower spring tray and correctly guide the design of the spring tray.

[0009] A method for modeling and simulating the strength and durability of the spring tray in a MacPherson strut suspension system includes the following:

[0010] Step 1: Based on the MacPherson suspension system parameter table, establish a MacPherson suspension system model with beam element topology equivalent;

[0011] Step 2: Adjust the cross-sectional dimensions of the beam element so that the hard point stiffness of the equivalent beam element is consistent with the stiffness of its corresponding real structure: subframe, steering knuckle, and control arm structure.

[0012] Step 3: Establish a simulation model of the spring tray, and perform geometric processing and mesh generation on the spring tray, upper spring pad, lower spring pad, helical spring, upper spring support, and upper damper support structure, and assign material and cross-sectional properties.

[0013] Step 4: Establish the contact relationship between the upper spring support and the upper shock absorber support, the upper spring pad and the upper spring support, the contact relationship between the helical spring and the upper spring pad and the lower spring pad, and the contact relationship between the lower spring pad and the lower spring tray.

[0014] Step 5: Replace the spring tray simulation model, which has been meshed, assigned attributes, and established contact relationships, with the model obtained in Step 1;

[0015] Step 6: Apply boundary conditions to constrain the connection points between the subframe and the body, the upper point of the shock absorber slide, and the fixing points of the bolts connecting the upper support of the shock absorber and the body (degrees of freedom 1-6).

[0016] Step 7: Wheel center loading. Apply the wheel's upper limit load and lower limit load to the wheel center. The load will be accurately transferred to the spring tray through the wheel center and the contact relationship between the coil spring and the lower spring bushing, and between the lower spring bushing and the spring tray, so as to obtain accurate spring tray stress calculation results and the deformation of the MacPherson suspension system.

[0017] Step 8: Import the stress of the spring tray under the wheel's upper and lower limits of bounce into the FEMFAT software, input the specified number of cycles, and calculate the durability damage of the spring tray.

[0018] The MacPherson suspension system parameter table in step one includes hard point coordinates, local coordinate system coordinates, and bushing stiffness information.

[0019] In step five, Hypermesh software is used to first import the MacPherson strut suspension system model established in step one, then import the spring tray simulation model, and finally delete the beam elements at the location of the spring tray simulation model in the MacPherson strut suspension system, thus completing the replacement of the spring tray simulation model part in the MacPherson strut suspension system.

[0020] Step seven involves exporting a calculation model file using Hypermesh software and submitting the file to ABAQUS software for calculation to obtain stress results, as well as the deformation of the MacPherson suspension system and the stress of the spring tray.

[0021] In step seven, first determine whether the deformation and contact relationship of the MacPherson suspension system are correct. If correct, then read the spring tray stress.

[0022] The load in step seven includes the contact area, size, and direction of the load.

[0023] The beneficial effects of this invention are:

[0024] First, when performing strength and durability simulation of the lower spring tray of the MacPherson suspension system, the beam element topology and stiffness equivalent suspension system model are used as the basis for simulation calculation.

[0025] Second, when performing strength and durability simulation of the lower spring tray of the MacPherson suspension system, a load is applied at the wheel center of the suspension system. Through the contact relationship, the contact area between the lower spring pad and the spring tray, and the contact area between the coil spring and the lower pad are accurately simulated, so as to accurately transmit the magnitude and action area of ​​the pressure load to the spring tray.

[0026] Third, when performing strength and durability simulation of the lower spring tray of the MacPherson suspension system, a load is applied at the wheel center of the suspension system. By establishing a coil spring, the tilt of the coil spring when the wheel bounces up and down is accurately simulated, and the load direction of the coil spring is accurately transmitted to the spring tray.

[0027] Fourth, when performing strength and durability simulation of the lower spring tray of the MacPherson suspension system, the boundary conditions at the connection point between the suspension system and the vehicle body are more closely related to the actual situation, making it more accurate compared to traditional calculation methods.

[0028] Fifth, when performing strength and durability simulation of the lower spring tray of the MacPherson suspension system, compared with traditional simulation methods, the simulation efficiency is not significantly increased due to the use of equivalent beam elements in the suspension system. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the content of the embodiments of the present invention and these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of the assembly model of the MacPherson suspension damper system of the present invention.

[0031] Figure 2 This is a schematic cross-sectional view of the assembly model of the MacPherson suspension damper system of the present invention.

[0032] Figure 3 This is a flowchart of the present invention.

[0033] Figure 4 This is a schematic diagram of the equivalent finite element model of the beam element topology of the MacPherson suspension system of the present invention.

[0034] Figure 5 This is a schematic diagram of the equivalent finite element model of the beam element stiffness of the MacPherson suspension system of the present invention.

[0035] Figure 6 This is a schematic diagram of the finite element model of the MacPherson suspension system after the actual structure of the tray and coil spring has been replaced. Detailed Implementation

[0036] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0037] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0038] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0039] In the description of this embodiment, the terms "upper," "lower," "left," and "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0040] Example 1

[0041] A method for modeling and simulating the strength and durability of the spring tray in a MacPherson strut suspension system includes the following:

[0042] Step 1: Based on the MacPherson suspension system parameter table, establish a MacPherson suspension system model with beam element topology equivalent;

[0043] Step 2: Adjust the cross-sectional dimensions of the beam element so that the hard point stiffness of the equivalent beam element is consistent with the stiffness of its corresponding real structure: subframe, steering knuckle, and control arm structure.

[0044] Step 3: Establish a simulation model of the spring tray, and perform geometric processing and mesh generation on the spring tray, upper spring pad, lower spring pad, helical spring, upper spring support, and upper damper support structure, and assign material and cross-sectional properties.

[0045] Step 4: Establish the contact relationship between the upper spring support and the upper shock absorber support, the upper spring pad and the upper spring support, the contact relationship between the helical spring and the upper spring pad and the lower spring pad, and the contact relationship between the lower spring pad and the lower spring tray.

[0046] Step 5: Replace the spring tray simulation model, which has been meshed, assigned attributes, and established contact relationships, with the model obtained in Step 1;

[0047] Step 6: Apply boundary conditions to constrain the connection points between the subframe and the body, the upper point of the shock absorber slide, and the fixing points of the bolts connecting the upper support of the shock absorber and the body (degrees of freedom 1-6).

[0048] Step 7: Wheel center loading. Apply the wheel's upper limit load and lower limit load to the wheel center. The load will be accurately transferred to the spring tray through the wheel center and the contact relationship between the coil spring and the lower spring bushing, and between the lower spring bushing and the spring tray, so as to obtain accurate spring tray stress calculation results and the deformation of the MacPherson suspension system.

[0049] Step 8: Import the stress of the spring tray under the wheel's upper and lower limits of bounce into the FEMFAT software, input the specified number of cycles, and calculate the durability damage of the spring tray.

[0050] The MacPherson suspension system parameter table in step one includes hard point coordinates, local coordinate system coordinates, and bushing stiffness information.

[0051] In step five, Hypermesh software is used to first import the MacPherson strut suspension system model established in step one, then import the spring tray simulation model, and finally delete the beam elements at the location of the spring tray simulation model in the MacPherson strut suspension system, thus completing the replacement of the spring tray simulation model part in the MacPherson strut suspension system.

[0052] Step seven involves exporting a calculation model file using Hypermesh software and submitting the file to ABAQUS software for calculation to obtain stress results, as well as the deformation of the MacPherson suspension system and the stress of the spring tray.

[0053] In step seven, first determine whether the deformation and contact relationship of the MacPherson suspension system are correct. If correct, then read the spring tray stress.

[0054] To determine whether the deformation of the MacPherson strut suspension system is correct, we mainly need to check whether there is significant deformation of the rubber bushings in the MacPherson strut suspension system, which would cause the suspension system to twist and be inconsistent with the wheel bounce limit state of the actual vehicle. For the contact relationship, we mainly need to check whether the contact relationship between the components established in step four has changed. If the deformation or contact relationship is incorrect, we need to check whether the boundary conditions applied to the system in step five are correct and whether there are any unconstrained situations. We also need to check whether the stiffness of the rubber bushing elements in the MacPherson strut suspension system model equivalent to the beam element topology established in step one is correct. If the system deformation is too large, it means that the stiffness of the rubber bushing is too small and the stiffness needs to be increased.

[0055] The load in step seven includes the contact area, size, and direction of the load.

[0056] Example 2

[0057] Explanation of the vehicle coordinate system: The positive X-axis (direction 1) is from the front to the rear of the vehicle, and the positive Z-axis (direction 3) is vertically upward. The positive Y-axis of the vehicle coordinate system is governed by the right-hand screw rule, and the rotation directions around the X, Y, and Z axes represent directions 4, 5, and 6, respectively.

[0058] In the simulation calculation of the strength and durability of the spring tray of the MacPherson strut suspension system, firstly, an equivalent MacPherson strut suspension system with beam element topology is established; secondly, the cross-sectional dimensions of the beam elements are adjusted so that the stiffness of the equivalent beam elements is consistent with the stiffness of the actual structures such as the subframe, steering knuckle, and control arm; thirdly, the structures such as the spring tray, upper and lower spring bushings, coil spring, upper spring support, and upper shock absorber support are geometrically processed and meshed, and material and cross-sectional properties are assigned; finally, contact relationships are established, specifically the contact relationship between the upper spring support and the upper shock absorber support, and the spring... The simulation process involves establishing the contact relationships between the upper spring bushing and the upper spring support, the coil spring and the upper and lower spring bushings, and the lower spring bushing and the lower spring tray. Next, 1-6 degrees of freedom are applied to the connection points between the MacPherson suspension system and the vehicle body, and upper and lower bounce loads are applied at the wheel center to calculate the stress cloud diagrams of the spring tray under the upper and lower bounce limit states. Finally, the stresses of the spring trays under the upper and lower bounce limit states are imported into the FEMFAT software, and the specified number of stress cycles is input to calculate the durability damage value. The flowchart for the MacPherson suspension system spring tray strength and durability simulation is as follows: Figure 3 As shown.

[0059] This section uses a MacPherson strut suspension system of a certain car model as an example to explain in detail the implementation steps of this method.

[0060] The first step is to establish a MacPherson strut suspension system model with an equivalent beam element topology based on the MacPherson strut suspension system parameter table, which includes hard point coordinates, local coordinate system coordinates, and bushing stiffness information. Figure 4 As shown, the topological equivalent suspension system model has all the structures in the real suspension model, except that all structures are first replaced by equivalent beam elements. It also has the characteristics of small model size and few elements and nodes.

[0061] The second step is to adjust the cross-sectional dimensions of the beam elements so that the hard-point stiffness of the equivalent beam elements is consistent with the stiffness of their corresponding real structures: the subframe, steering knuckle, and control arm. The equivalent stiffness model of the beam elements is as follows: Figure 5 As shown;

[0062] The third step involves geometric processing and mesh generation of the spring tray, upper spring pad, lower spring pad, coil spring, upper spring support, and upper damper support structure, and assigning material and section properties to them.

[0063] The fourth step is to establish the contact relationship between the upper spring support and the upper shock absorber support, the contact relationship between the upper spring pad and the upper spring support, the contact relationship between the helical spring and the upper spring pad and the lower spring pad, and the contact relationship between the lower spring pad and the lower spring tray.

[0064] The fifth step involves replacing the spring tray simulation model, which has been meshed, assigned attributes, and had its contact relationships established, into the equivalent suspension system model of the MacPherson suspension system beam element, i.e., the MacPherson suspension system model obtained in step one. Figure 6 As shown;

[0065] Step 5: Apply boundary conditions to constrain the subframe-to-body connection point, the upper point of the shock absorber strut, and the fixing points of the upper shock absorber support and the body connection bolts (degrees of freedom 1-6), such as... Figure 6 As shown;

[0066] Step 6: Wheel center loading. Apply both the upper and lower limit loads at the wheel center. The loads are accurately transferred to the spring tray through the wheel center and the contact relationships between the coil spring and the lower spring bushing, and between the lower spring bushing and the spring tray. This includes the contact area, magnitude, and direction of the loads, thus obtaining accurate stress calculation results for the spring tray. Figure 6 As shown;

[0067] Step 7: Import the stress of the spring tray under the wheel's upper and lower limit states into the FEMFAT software, input the specified number of cycles, and calculate the durability damage of the spring tray.

[0068] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the scope of protection of the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, any person skilled in the art can make equivalent substitutions or changes based on the technical solution and inventive concept of the present invention within the scope of the technology disclosed in the present invention. These simple modifications are all within the scope of protection of the present invention.

[0069] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0070] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A method for modeling and simulating the strength and durability of the spring tray in a MacPherson strut suspension system, characterized in that, Includes the following: Step 1: Based on the MacPherson suspension system parameter table, establish a MacPherson suspension system model with beam element topology equivalent; Step 2: Adjust the cross-sectional dimensions of the beam element so that the hard point stiffness of the equivalent beam element is consistent with the stiffness of its corresponding real structure: subframe, steering knuckle, and control arm structure. Step 3: Establish a simulation model of the spring tray, and perform geometric processing and mesh generation on the spring tray, upper spring pad, lower spring pad, helical spring, upper spring support, and upper damper support structure, and assign material and cross-sectional properties. Step 4: Establish the contact relationship between the upper spring support and the upper shock absorber support, the upper spring pad and the upper spring support, the contact relationship between the helical spring and the upper spring pad and the lower spring pad, and the contact relationship between the lower spring pad and the lower spring tray. Step 5: Replace the spring tray simulation model, which has been meshed, assigned attributes, and established contact relationships, with the model obtained in Step 1; Step 6: Apply boundary conditions to constrain the connection points between the subframe and the vehicle body, the upper point of the shock absorber slide, and the fixing points of the bolts connecting the upper support of the shock absorber and the vehicle body (degrees of freedom 1-6). Step 7: Wheel center loading. Apply the wheel's upper limit load and lower limit load to the wheel center. The load will be accurately transferred to the spring tray through the wheel center and the contact relationship between the coil spring and the lower spring bushing, and between the lower spring bushing and the spring tray, so as to obtain accurate spring tray stress calculation results and the deformation of the MacPherson suspension system. Step 8: Import the stress of the spring tray under the wheel's upper and lower limits of bounce into the FEMFAT software, input the specified number of cycles, and calculate the durability damage of the spring tray.

2. The method for modeling and simulating the strength and durability of a MacPherson strut suspension system spring tray according to claim 1, characterized in that, The MacPherson suspension system parameter table in step one includes hard point coordinates, local coordinate system coordinates, and bushing stiffness information.

3. The method for modeling and simulating the strength and durability of a MacPherson strut suspension system spring tray according to claim 1, characterized in that, In step five, Hypermesh software is used to first import the MacPherson strut suspension system model established in step one, then import the spring tray simulation model, and finally delete the beam elements at the location of the spring tray simulation model in the MacPherson strut suspension system, thus completing the replacement of the spring tray simulation model part in the MacPherson strut suspension system.

4. The method for modeling and simulating the strength and durability of a MacPherson strut suspension system spring tray according to claim 1, characterized in that, Step seven involves exporting a calculation model file using Hypermesh software and submitting the file to ABAQUS software for calculation to obtain stress results, as well as the deformation of the MacPherson suspension system and the stress of the spring tray.

5. The method for modeling and simulating the strength and durability of a MacPherson strut suspension system spring tray according to claim 1, characterized in that, In step seven, first determine whether the deformation and contact relationship of the MacPherson suspension system are correct. If correct, then read the spring tray stress.

6. The method for modeling and simulating the strength and durability of a MacPherson strut suspension system spring tray according to claim 1, characterized in that, The load in step seven includes the contact area, size, and direction of the load.

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