Automobile engine hood baking deformation simulation method

Abstract

The invention relates to an automobile engine hood baking deformation simulation method, and relates to the technical field of automobile body manufacturing. The method comprises the following steps: extracting a CAD digital model of an automobile engine hood assembly from three-dimensional modeling software of automobile body design; importing the digital analog into pretreatment software to generate a part grid of the automobile engine hood assembly; the part grids are imported into simulation software; setting a support reference point of the part grid, a hood material characteristic parameter, a damping rubber characteristic parameter and an external loading condition; and simulation analysis is carried out according to analysis steps corresponding to preset coating and baking procedures, and a deformation cloud picture of the automobile engine hood assembly affected by temperature change and damping glue expansion and curing is generated. By adopting the method, product structure factors influencing engine hood baking deformation can be predicted and analyzed in the early stage of a new vehicle type project.

Description

Technical Field

[0001] This application relates to the technical field of automobile body manufacturing, and particularly to a simulation method for the baking deformation of an automobile hood. Background Art

[0002] Currently, in the process of automobile manufacturing, the painting and baking process is an important link to ensure the surface coating performance of body parts. However, during the baking process, due to temperature changes and material property differences, body parts (such as hoods) may warp and deform. Especially under the influence of the expansion and curing of shock-absorbing rubber, the hood often shows irreversible local deformation, which has a greater impact on product quality. Currently, the analysis method for painting and baking deformation usually adopts on-site tests. This method is not only costly and time-consuming, but also requires a large number of molds and toolings for repeated verification and adjustment, making it difficult to meet the requirements of efficient development.

[0003] Due to the lack of comprehensive consideration of material thermal expansion and mechanical behavior during the painting and baking process, it is difficult to effectively predict the deformation area of the hood during temperature changes and the expansion and curing process of shock-absorbing rubber. Further, this method often relies on post-detection and fails to discover potential problems in advance through simulation technology during the design stage, resulting in waste of molds, frequent process adjustments, and a large consumption of human and material resources. Summary of the Invention

[0004] Based on this, in view of the above technical problems, it is necessary to provide a simulation method for the baking deformation of an automobile hood, and the method includes:

[0005] Extract the CAD digital model of the automobile hood assembly from the three-dimensional modeling software for automobile body design;

[0006] Import the digital model into the pre-processing software to generate the part mesh of the automobile hood assembly;

[0007] Import the part mesh into the simulation software;

[0008] Set the support reference points of the part mesh, the material property parameters of the hood, the property parameters of the shock-absorbing rubber, and the external loading conditions;

[0009] Perform simulation analysis according to the analysis steps corresponding to the preset painting and baking process to generate the deformation cloud diagram of the automobile hood assembly under the influence of temperature changes and the expansion and curing of the shock-absorbing rubber.

[0010] As an optional implementation manner, the method further includes:

[0011] Export the CAD digital model of the automobile hood assembly to the file format supported by the pre-processing software;

[0012] Convert the part mesh into the format supported by the simulation software.

[0013] As an alternative implementation, the grid size of the part grid is selected in the range of 5-10 mm.

[0014] As an alternative implementation, the support reference points include the front support point of the hood and the rear support point of the hood.

[0015] As an alternative implementation, the material property parameters include the hood material property parameters and the damping rubber property parameters. The hood material property parameters include sheet metal density, sheet metal elastic modulus, sheet metal Poisson's ratio, and sheet metal thermal expansion coefficient;

[0016] The damping rubber property parameters include damping rubber density, damping rubber elastic modulus, damping rubber Poisson's ratio, and damping rubber thermal expansion coefficient.

[0017] As an alternative implementation, the external loading conditions include gravitational acceleration.

[0018] As an alternative implementation, the preset analysis steps include a gravity loading step, a heating step, and a cooling step.

[0019] As an alternative implementation, the heating step includes:

[0020] Raising the automotive hood assembly from a preset first baking temperature to a preset second baking temperature.

[0021] As an alternative implementation, the cooling step includes:

[0022] Lowering the automotive hood assembly from the preset second baking temperature to the preset first baking temperature.

[0023] As an alternative implementation, the preset first baking temperature is 25 °C, and the preset second baking temperature is 200 °C.

[0024] In a second aspect, a computer device is provided, including a memory and a processor. A computer program that can run on the processor is stored on the memory. When the processor executes the computer program, the method steps described in any item of the first aspect are implemented.

[0025] In a third aspect, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the method steps described in any item of the first aspect are implemented.

[0026] The present application provides a simulation method for the baking deformation of an automotive hood. The technical solutions provided by the embodiments of the present application at least bring the following beneficial effects. The method includes: extracting the CAD digital model of the automotive hood assembly from the three-dimensional modeling software for automotive body design; importing the digital model into the pre-processing software to generate the part mesh of the automotive hood assembly; importing the part mesh into the simulation software; setting the support reference points, material property parameters, and external loading conditions of the automotive hood assembly; performing simulation analysis according to the preset analysis steps to generate the deformation nephogram of the automotive hood assembly with temperature change. By using the method of the present application, it is possible to predict the product structure factors affecting the baking deformation of the hood in the early stage of a new vehicle model project and adjust the digital model with large deformation. At the same time, it is possible to predict the influence of different process designs on the baking deformation of the hood (such as baking support points, heating rate of the baking room, and blowing air volume) to meet the requirements. It can effectively avoid the problems of product redesign, scrapping of tooling fixtures and inspection tools once the hood deformation is found after the mass production ramp-up of the vehicle model project.

[0027] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the present application. Brief Description of the Drawings

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention, and those of ordinary skill in the art can obtain other drawings without creative efforts based on these drawings.

[0029] Figure 1 It is a flowchart of a simulation method for the baking deformation of an automotive hood provided by an embodiment of the present application;

[0030] Figure 2 It is a flowchart of an example of a simulation method for the baking deformation of an automotive hood provided by an embodiment of the present application;

[0031] Figure 3 It is a schematic diagram of a support reference point provided by an embodiment of the present application;

[0032] Figure 4 It is a schematic diagram of the structure of a computer device provided by an embodiment of the present application. Detailed Description of the Embodiments

[0033] In order to make the purpose, technical solutions and advantages of the present application clearer, the following will further describe the present application in detail with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0034] The following will, in conjunction with specific embodiments, provide a detailed description of a method for simulating the baking deformation of an automotive hood provided by an embodiment of the present application. Figure 1 It is a flowchart of a method for simulating the baking deformation of an automotive hood provided by an embodiment of the present application. As Figure 1 shown, the specific steps are as follows:

[0035] Step 101: Extract the CAD digital model of the automotive hood assembly from the three-dimensional modeling software for automotive body design.

[0036] In implementation, the CAD digital model is a digital representation of the geometric and structural information of the automotive hood assembly and is the basic data source for finite element analysis. By extracting the complete digital model from the three-dimensional modeling software, the accuracy of the input data for simulation analysis can be ensured. For example: In the CATIA design software, the hood assembly model can be opened, the export function can be selected, and the CAD digital model of the hood assembly can be saved in the STEP format to a local folder. During the export process, the geometric accuracy of the digital model can be set, such as not less than 0.01 mm, to provide accurate geometric data for subsequent simulation.

[0037] Step 102: Import the digital model into the pre-processing software to generate the part mesh of the automotive hood assembly.

[0038] In implementation, the pre-processing software can discretize the continuous geometric model through mesh generation to generate the elements required for finite element analysis. The size and quality of the mesh directly affect the accuracy and calculation efficiency of the simulation results. For example: The HyperMesh software can be used to import the STEP file generated in Step 101 and perform mesh generation on the digital model of the automotive hood assembly. The specific steps can include setting the mesh type as quadrilateral mesh and the mesh size as 7 mm. Among them, the local complex areas (such as edges or connection parts) are adjusted to 5 mm to improve accuracy. Ensure that the aspect ratio of the mesh does not exceed 5:1 and the twist angle is less than 45°. The mesh file is exported in the.inp format for subsequent simulation.

[0039] Step 103: Import the part mesh into the simulation software.

[0040] In implementation, the simulation software can establish a finite element model by loading the part mesh. The integrity and correctness of the model will directly affect the reliability of the simulation results. For example: The Abaqus simulation software can be used to import the.inp format mesh file generated in Step 102. After loading, check whether there are broken elements or unconnected nodes in the model. Repair the discovered problem elements to ensure the continuity of the model mesh and the correctness of the boundary conditions.

[0041] Step 104: Set the support reference points of the part mesh, the material property parameters of the hood, the property parameters of the damping rubber, and the external loading conditions.

[0042] In implementation, the support reference points can determine the specific positions where the tooling supports the hood during the painting and baking process, simulating the actual tooling support conditions. The material property parameters describe the physical responses of the sheet metal and the damping rubber under mechanical and thermal conditions. The external loading conditions simulate the external force changes that actually occur during the painting and baking process.

[0043] Step 105: Conduct a simulation analysis according to the analysis steps corresponding to the preset painting and baking process to generate a deformation nephogram of the automotive hood assembly affected by temperature changes and the expansion and curing of the damping rubber.

[0044] In implementation, through finite element analysis, simulate the influence of the expansion and curing of the damping rubber on the hood deformation during the painting and baking process, including the deformation under the combined action of temperature gradient, thermal expansion stress, and gravity. The simulation analysis provides quantitative results on the deformation area and its severity, providing a basis for improving the painting process. For example: Set the gravity loading step to apply a gravity field to simulate the influence of the self-weight of the hood under the tooling support conditions. Set the hood to heat up from 25°C to 200°C at a heating rate of 10°C per minute, and then set the hood to cool down from 200°C to 25°C at a cooling rate of 10°C per minute. Start the Abaqus simulation task to analyze the temperature distribution and deformation response over time during the painting and baking process. View the analysis results in the "Visualization" module of Abaqus, generate a deformation nephogram of the automotive hood assembly, record the maximum deformation amount and the main deformation areas, and analyze the specific influence of the expansion and curing of the damping rubber on the hood deformation.

[0045] As an alternative implementation method, the method further includes:

[0046] Export the CAD digital model of the automotive hood assembly to a file format supported by the pre-processing software; convert the part mesh into a format supported by the simulation software.

[0047] In implementation, different preprocessing software has different supported formats for CAD files. Exporting the CAD digital model to a compatible format can avoid data loss or conversion errors and improve the accuracy of mesh generation. Commonly supported file formats include STEP, IGES, and PDGS, etc. For example: In the CATIA 3D modeling software, open the CAD model of the car hood assembly, export it as a STEP file, and export the STEP file to the specified directory. Similarly, different simulation software has different format requirements for mesh files. By converting the mesh file format, the compatibility of the finite element model can be ensured, and errors caused by format problems during simulation operation can be avoided. Commonly supported mesh formats include.inp,.nas, and.cdb, etc. For example: In the HyperMesh preprocessing software, the generated STEP file can be imported, mesh division can be completed, the "Export" function can be selected, and the export format can be set to.inp format in the pop-up window, and the mesh file can be saved in a format supported by the simulation software Abaqus for subsequent simulation analysis.

[0048] As an alternative implementation, the selected range of the mesh size of the part mesh is 5 - 10 mm.

[0049] In implementation, the smaller the mesh size, the closer the result of the simulation analysis is to the actual data, but too small a size can cause the simulation analysis to run for too long. Generally, the mesh size for sheet metal deformation can be selected as 5 - 10 mm.

[0050] As an alternative implementation, the support reference points include the front support point of the hood and the rear support point of the hood.

[0051] In implementation, Figure 3 This is a schematic diagram of a support reference point provided by an embodiment of the present application. As Figure 3 shown, one support point (such as the leading edge center position 1) at the front end of the car hood and two support points (such as the positions 2 and 3 near the rear of the two sides) at the rear end can be defined, and the support reference points can be set as fixed constraints.

[0052] As an alternative implementation, the material property parameters include the hood material property parameters and the damping rubber property parameters. The hood material property parameters include sheet metal density, sheet metal elastic modulus, sheet metal Poisson's ratio, and sheet metal thermal expansion coefficient;

[0053] The damping rubber property parameters include damping rubber density, damping rubber elastic modulus, damping rubber Poisson's ratio, and damping rubber thermal expansion coefficient.

[0054] In implementation, the sheet metal material property parameters reflect the response behavior of the hood during the painting and baking process when subjected to force and heat. Among them, the sheet metal density is used to calculate the gravitational load, and the elastic modulus and Poisson's ratio of the sheet metal can describe the linear elastic deformation characteristics of the sheet metal material. The coefficient of thermal expansion can be used to characterize the dimensional change behavior of the sheet metal material under temperature changes. For example: the sheet metal density can be set to 7.85 g / cm 3 , the elastic modulus of the sheet metal can be set to 210 GPa, the Poisson's ratio of the sheet metal can be set to 0.3, and the coefficient of thermal expansion of the sheet metal can be set to 12×10^-6 / °C. The setting method can be in the Abaqus software, open the "Property" module, select "Material", create a new hood material property, input the above parameters item by item, and name it. The material properties of the damping rubber directly affect its expansion behavior during high-temperature baking. Among them, the damping rubber density is used to calculate the influence of the damping rubber weight on the deformation of the hood, and the elastic modulus and Poisson's ratio of the damping rubber can describe its rigidity after curing. The coefficient of thermal expansion of the damping rubber is used to characterize its volume change during the heating process. For example: the damping rubber density can be set to 1.2 g / cm 3 , the elastic modulus of the damping rubber can be set to 2 MPa, the Poisson's ratio of the damping rubber can be set to 0.49, and the coefficient of thermal expansion of the damping rubber can be set to 150×10^-6 / °C. The setting method can be in the Abaqus software, select "Property>Material", create a new damping rubber property, input the above damping rubber characteristic parameters item by item, and name it. It is also possible to assign the defined material properties to the finite element model elements of the hood and the damping rubber to ensure that the physical behaviors of different components in the simulation analysis can be accurately expressed. After the assignment is completed, it is possible to check whether the material assignment covers all corresponding elements and save the model.

[0055] As an alternative implementation, the external loading conditions include gravitational acceleration.

[0056] In implementation, gravity is an important external load that affects the deformation of the automotive hood during the painting and baking process. By applying gravitational acceleration, the stress and deformation distributions of the automotive hood under its own weight can be simulated, and thus its deformation behavior can be predicted more accurately. The commonly used value of gravitational acceleration is 9.8 m / s 2 . For example: in the Abaqus software, enter the "Load" module, select "CreateLoad", the type is "Gravity", select the region "Region" as "WholeModel", so as to specify that the scope of gravitational loading is the entire hood structure, and enter the gravitational acceleration value 9.8 m / s in the "Magnitude" field 2 , save the settings, and check whether the loading conditions are applied correctly.

[0057] As an alternative implementation, the load distribution can be observed through a visualization tool to confirm whether the gravity load covers all model elements. If any abnormalities are found (such as incorrect direction or omitted area), the "Load" module can be returned to adjust the gravity settings.

[0058] As an alternative implementation, the preset analysis steps include a gravity loading step, a heating step, and a cooling step. Among them, the heating step is to raise the automotive hood assembly from a preset first baking temperature to a preset second baking temperature. The cooling step is to lower the automotive hood assembly from the preset second baking temperature to the preset first baking temperature.

[0059] In implementation, in the painting baking simulation, gravity loading is the basic condition. By applying a gravity load, the initial deformation and stress distribution of the automotive hood under its own weight are analyzed. For example: in the Abaqus software, the "Step" module can be selected, a new analysis step "GravityLoadStep" can be created, and the type can be set to "Static,General". The time step can be set to 1 to ensure that other conditions can be connected after this step. The "GravityLoad" condition can be defined, the direction can be selected as the negative Z-axis, and the magnitude can be set to 9.81 m / s 2. Save the settings and run to output the initial stress field and displacement field of the hood under its own weight. The heating step can simulate the working condition of the automotive hood gradually increasing in temperature during the painting and baking process. The temperature increase causes thermal expansion of the sheet metal and damping rubber, and may cause stress concentration and local deformation. For example: In the Abaqus software, a new analysis step "HeatingStep" can be created, with the type "Static,General", the initial temperature set to 25°C, the target temperature set to 200°C, the thermal loading conditions defined, the hood surface selected as the thermal load area, the temperature set to increase linearly with time, run the heating simulation, and output the temperature field and the stress and displacement distributions caused by thermal expansion. The cooling step can simulate the process of the automotive hood cooling from a high temperature to room temperature after baking. During this process, the damping rubber cures, and internal stresses may cause warping deformation or residual stress distribution. For example: In the Abaqus software, a new analysis step "CoolingStep" can be created, with the type "Static,General", the initial temperature set to 200°C, the target temperature set to 25°C, the thermal loading conditions defined, the temperature set to decrease linearly with time, in the "Material" module, ensure that the damping rubber material properties include a curing behavior model to simulate the change in elastic modulus during the temperature decrease process, run the cooling simulation, and output the final displacement contour or residual stress distribution. Through the three analysis steps, the full-process deformation distribution of the hood during the painting and baking process due to gravity, thermal expansion, and damping rubber curing can be obtained. The warping deformation area of the automotive hood during the heating and cooling processes can be analyzed based on the deformation distribution, the key dimension changes can be output, and the painting and baking process or the hood structure design can be adjusted according to the analysis results.

[0060] As an alternative implementation, the preset first baking temperature is 25°C, and the preset second baking temperature is 200°C.

[0061] As an alternative implementation, Figure 2 is a flowchart of an example of a method for simulating the baking deformation of an automotive hood provided by an embodiment of the present application, as Figure 2 shown, and the specific steps are as follows:

[0062] Step 201, export the digital model of the automotive hood assembly, export the digital model from the CAD software, and generate a mesh in the pre-processing software (Hyperwork).

[0063] Step 202, import the digital model into the pre-processing software (Hyperwork) and draw a mesh.

[0064] Step 203, import the drawn mesh into the simulation software (abaqus).

[0065] Step 204, define the support reference points for the baking process.

[0066] Step 205: Set characteristic values (related parameters: density, modulus, coefficient of thermal expansion, Poisson's ratio, temperature).

[0067] Step 206: Set the loads, constraints, contacts, and analysis steps applied to the model.

[0068] Step 207: Run the simulation software to conduct a simulation analysis.

[0069] Step 208: Post-process to view the deformation nephogram.

[0070] The embodiment of the present application provides a simulation method for the baking deformation of an automotive hood. The method includes: extracting the CAD digital model of the automotive hood assembly from the three-dimensional modeling software for automotive body design. Importing the digital model into the pre-processing software to generate the part mesh of the automotive hood assembly. Importing the part mesh into the simulation software. Setting the support reference points, material characteristic parameters, and external loading conditions of the automotive hood assembly. Conducting a simulation analysis according to the preset analysis steps to generate the deformation nephogram of the automotive hood assembly varying with temperature. By using the method of the present application, it is possible to predict the warping deformation areas caused by the expansion and curing of the damping rubber and temperature changes through the simulation analysis of the hood baking process, providing data support for optimizing the hood design and painting process in advance. By replacing the actual test with simulation, it is possible to significantly reduce the cycle and cost of sample production and process testing, and at the same time avoid the waste of resources caused by multiple test adjustments. Through the simulation analysis of the material characteristic parameters of the sheet metal and the damping rubber, the influence of different materials on the hood deformation can be evaluated, thereby guiding the selection of better materials and the improvement of the structure. Combining the simulation results of the heating and cooling steps, the temperature curve and heating / cooling rate of the painting process can be optimized, reducing the influence of the process on the shape accuracy of the hood. By simulating the actual working conditions, the probability of accidental deformation during the baking process can be reduced, ensuring the consistency of product quality in mass production. The simulation analysis results can provide a basis for the design of tooling and molds, avoiding repeated modifications caused by design problems and reducing the scrap rate of tooling and molds.

[0071] It should be understood that although Figure 1 and Figure 2 the steps in the flowcharts of Figure 1 and Figure 2 are shown sequentially according to the arrows, these steps do not necessarily have to be executed in the order indicated by the arrows. Unless there is a clear indication in this article, the execution of these steps has no strict order limit, and these steps can be executed in other orders. Moreover,

[0072] It can be understood that for the same / similar parts among the various embodiments of the above methods in this specification, reference can be made to each other. Each embodiment focuses on the differences from other embodiments. For the relevant parts, reference can be made to the descriptions of other method embodiments.

[0073] In one embodiment, a computer device is provided, as Figure 4 shown, including a memory and a processor. A computer program that can run on the processor is stored on the memory. When the processor executes the computer program, the method steps of the above-mentioned automotive hood baking deformation simulation are implemented.

[0074] In one embodiment, a computer-readable storage medium has a computer program stored thereon. When the computer program is executed by a processor, the steps of the method of the above-mentioned automotive hood baking deformation simulation are implemented.

[0075] Those of ordinary skill in the art can understand that all or part of the processes in implementing the methods of the above embodiments can be completed by instructing relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above various methods. Among them, any reference to a memory, storage, database, or other medium used in the various embodiments provided in this application can include non-volatile and / or volatile memories. Non-volatile memories can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memories can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.

[0076] It should be noted that, in this document, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprising", "including" or any other variant thereof are intended to cover non-exclusive inclusion, such that a process, method, article or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, article or device comprising the said element.

[0077] It should also be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data for display, data for analysis, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties.

[0078] Each embodiment in this specification is described in a related manner. The same or similar parts among the embodiments can be referred to each other, and the differences between each embodiment and other embodiments are emphasized. In particular, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the description of the method embodiment.

[0079] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as within the scope described in this specification.

[0080] The above-described embodiments only represent several implementation manners of this application. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of this application, several modifications and improvements can still be made, and these all belong to the protection scope of this application. Therefore, the protection scope of this application patent shall be subject to the appended claims.

Claims

1. A method for simulating the baking deformation of a car hood, characterized in that: The method comprises: Extract the CAD digital model of the automobile hood assembly from the 3D modeling software for automobile body design; Importing the digital model into the pre-processing software to generate a parts mesh of the automobile hood assembly; importing the part mesh into simulation software; Setting the support reference points of the part grid, characteristic parameters of the cover material, characteristic parameters of the shock absorbing rubber and external loading conditions; A simulation analysis is performed according to the analysis steps corresponding to the preset coating and baking process to generate a deformation cloud map of the automobile hood assembly affected by temperature changes and the expansion and curing of the shock-absorbing glue.

2. The method according to claim 1, characterized in that The method further comprises: Exporting the CAD digital model of the automobile hood assembly into a file format supported by the pre-processing software; The part mesh is converted into a format supported by the simulation software.

3. The method according to claim 1, characterized in that The mesh size of the part mesh is selected in the range of 5-10 mm.

4. The method according to claim 1, characterized in that: The support reference points include a hair hood front end support point and a hair hood rear end support point.

5. The method according to claim 1, characterized in that The characteristic parameters of the hair cover material include sheet metal density, sheet metal elastic modulus, sheet metal Poisson's ratio and sheet metal thermal expansion coefficient; The characteristic parameters of the shock-absorbing rubber include the density of the shock-absorbing rubber, the elastic modulus of the shock-absorbing rubber, the Poisson's ratio of the shock-absorbing rubber and the thermal expansion coefficient of the shock-absorbing rubber.

6. The method according to claim 1, characterized in that The external loading condition includes gravitational acceleration.

7. The method according to claim 1, characterized in that The preset analysis steps include a gravity loading step, a temperature increasing step and a temperature decreasing step.

8. The method according to claim 7, characterized in that The temperature raising step comprises: The automobile hood assembly is heated from a preset first baking temperature to a preset second baking temperature.

9. The method according to claim 7, characterized in that: The cooling step comprises: The automobile hood assembly is lowered from a preset second baking temperature to a preset first baking temperature.

10. The method according to claim 8 or 9, characterized in that: The preset first baking temperature is 25°C, and the preset second baking temperature is 200°C.

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