An automated modeling and analysis method for subframe durability performance based on CAE simulation analysis

Abstract

The present invention proposes an automatic modeling and analysis method for the durability performance of a subframe bench based on CAE simulation analysis, which belongs to the technical field of frame structure analysis. The method is based on the subframe CAE mesh structure finite element model, uses the TCL scripting language automation program to perform automatic modeling of welds, and establishes a local coordinate system and bushing BEAM unit for connecting hard points; connects the subframe parts in the finite element through welding points, welds, bolts and bushing BEAM units to generate a complete subframe structure finite element model; performs automatic modeling of load nodes, load steps and analysis steps on the subframe structure finite element model, performs simulation analysis of the subframe CAE bench durability performance under various working conditions, inputs the simulation analysis results into the subframe bench durability performance EXCEL template file, and automatically calculates the life or damage value of the subframe under various working conditions. It can improve the efficiency and accuracy of subframe bench analysis.

Description

Technical Field

[0001] The invention relates to an automatic modeling and analysis method for the durability performance of a subframe bench based on CAE simulation analysis, and belongs to the technical field of frame structure analysis. Background Art

[0002] In today's fiercely competitive automobile market and with shorter product development cycles, it is increasingly important to develop automobile products with better performance in a shorter period of time. Therefore, CAE simulation technology is widely used in the process of automobile product development to conduct efficient and fast simulation analysis and optimization of product performance. The durability of the automobile chassis subframe bench is an important performance indicator of automobile product quality, and simulation modeling and analysis of the subframe bench is of great significance.

[0003] In the simulation modeling process of the subframe bench, it is necessary not only to model the overall structure of the subframe, but also to model the subframe welds, extract the connection hard points between the car body and the subframe, create the local coordinate system of the hard points, etc. At present, the creation of these details is still in the manual modeling stage. The stiffness of the subframe connection hard point is the stiffness under the local coordinate system, and the local coordinate system needs to be consistent with the local coordinate system of the bushing at the corresponding position. Therefore, when establishing the subframe bench durability finite element model, each connection point of the subframe first establishes a local coordinate system with a specified direction and a BEAM unit with stiffness to simulate the bushing. There are dozens of connection points between the body and the subframe related system parts. Manually establishing multiple or even dozens of coordinate systems and BEAM units is time-consuming, labor-intensive, and prone to errors. In addition, when performing durability analysis on the subframe bench in the current industry, it is necessary to manually create load excitations in the three directions of X, Y, and Z for the subframe connection hard points one by one, and it is also necessary to create analysis steps in three directions for each connection hard point. At the same time, when creating analysis steps, it is also necessary to associate the load excitation at each connection hard point with the corresponding analysis step. If all are created manually, it will not only take a long time, but also be easy to associate errors, find and correct errors, and affect the efficiency and accuracy of subframe modeling and analysis.

[0004] Current subframe durability simulation analysis also requires CAE simulation analysis of the suspension system under various working conditions, calculation and output of stress and strain data of the subframe under various working conditions, input into fatigue analysis software, and reset material properties, analysis parameters, etc. These operations are also time-consuming and labor-intensive, and there are differences in calculation methods for different software, and unified standardization cannot be achieved within the industry.

[0005] The above problems restrict the development of the automobile industry. How to realize automated and standardized CAE simulation analysis of subframe durability is a problem that needs to be solved in the existing technology. Summary of the invention

[0006] The purpose of the present invention is to provide an automated modeling and analysis method for the durability performance of a subframe bench based on CAE simulation analysis, so as to overcome the problems of low efficiency and low accuracy of existing modeling. The present invention utilizes an automated program to assist in constructing a subframe finite element model, and realizes automated analysis of the durability performance of the subframe bench based on the inner and outer surface stress data of each grid unit output under each working condition and a preset EXCEL template file, thereby greatly improving work efficiency and standardization.

[0007] To achieve the above object, the present invention is implemented by adopting the following technical solutions:

[0008] The present invention provides a method for automatically modeling and analyzing the durability performance of a subframe test bench based on CAE simulation analysis, comprising the following steps:

[0009] Use CAE simulation analysis software to divide the structural mesh of each component of the subframe CAD digital model and build the subframe CAE mesh structure finite element model;

[0010] Using TCL scripting language automation program to automatically model the weld seam based on the subframe CAE grid structure finite element model, a simplified weld seam model was obtained;

[0011] Using the TCL scripting language automation program, the local coordinate system of the connection hard point and the bushing BEAM unit are established according to the preset EXCEL template file of the connection hard point coordinates and the local coordinate system direction coordinates;

[0012] Connect the parts in the sub-frame CAE grid structure finite element model through welding point units, weld simplified models, bolt simplified models and bushing BEAM units to generate a complete sub-frame structure finite element model;

[0013] The subframe structure finite element model is automatically modeled with load nodes, load steps and analysis steps through the pre-built CAE load node and load step automation program and analysis step automation program, and the subframe bench durability performance analysis finite element model is obtained;

[0014] By modifying the load amplitude or load curve of the subframe bench durability performance analysis finite element model, the subframe CAE bench durability performance simulation analysis under various working conditions is performed to obtain the subframe CAE simulation analysis results under various working conditions;

[0015] The CAE simulation analysis results of the subframe under various working conditions are input into the pre-built subframe bench durability performance EXCEL template file to obtain the life or damage value of the subframe under various working conditions.

[0016] Furthermore, the TCL scripting language automation program is used to perform weld automation modeling on the basis of the subframe CAE grid structure finite element model to obtain a weld simplified model, including:

[0017] Get the TCL scripting language automation program for weld seam automation modeling;

[0018] Obtain the weld connection information based on the subframe CAD digital model and obtain the center line of the weld geometry;

[0019] By running the TCL scripting language automation program and selecting the center line of the weld geometry, the weld connecting two adjacent parts in the subframe CAE mesh structure finite element model is automatically generated to obtain a simplified weld model.

[0020] Furthermore, the EXCEL template file of the connection hard point coordinates and the local coordinate system direction coordinates includes the coordinates of all the connection hard points between the subframe and the vehicle body, the coordinates of the end points of the bushing BEAM unit and the local coordinate system direction coordinates of the connection hard points.

[0021] Furthermore, the TCL scripting language automation program is used to establish the local coordinate system of the connection hard point and the bushing BEAM unit according to the preset EXCEL template file of the connection hard point coordinates and the local coordinate system direction coordinates, including:

[0022] According to the connection position information of the subframe and the vehicle body mounting points in the subframe CAD digital model, the coordinates of each connection hard point in the subframe are obtained;

[0023] Obtain the coordinates of both end points of the bushing BEAM unit and the corresponding local coordinate system direction coordinates according to the CAD digital model of the subframe, and generate an EXCEL template file connecting the hard point coordinates and the local coordinate system direction coordinates;

[0024] Get the TCL scripting language automation program for establishing local coordinate system and bushing BEAM unit;

[0025] Determine whether the connection hard point coordinates and local coordinate system direction coordinates in the EXCEL template file are consistent with the connection hard point coordinates in the subframe CAE mesh structure finite element model or whether the distance tolerance is less than the predetermined tolerance, and determine whether the two end point coordinates of the bushing BEAM unit in the two are consistent or whether the distance tolerance is less than the predetermined tolerance;

[0026] If the coordinates are consistent or the distance tolerance is less than the preset tolerance, the TCL script language automation program is run according to the EXCEL template file of the connection hard point coordinates and the local coordinate system direction coordinates to automatically establish the local coordinate system of the connection hard point and the bushing BEAM unit.

[0027] Furthermore, the load nodes and load steps of the subframe bench finite element model are automatically set through the pre-built CAE load node and load step automation program, including:

[0028] Set the load node number;

[0029] Create six node sets for each load node in the six degrees of freedom directions;

[0030] The node numbers are assigned through the computer loop language of the CAE simulation analysis software, and the corresponding analysis loads of each node are written by defining the load amplitude or load curve in each direction of each node, thereby obtaining the load nodes and load steps.

[0031] Furthermore, the analysis steps of the subframe bench finite element model are automatically set up through the pre-built analysis step automation program, including:

[0032] Associate the created load amplitude or load curve with the corresponding analysis step;

[0033] Define the analysis type and analysis output result type of the subframe bench durability analysis;

[0034] The computer cycle language of CAE simulation analysis software automatically creates analysis steps in all directions of all connection hard points.

[0035] Further, the subframe structure finite element model includes a plurality of mesh elements;

[0036] The subframe CAE simulation analysis results under various working conditions are input into a pre-built subframe bench durability performance EXCEL template file to obtain the life or damage value of the subframe under various working conditions, including:

[0037] Obtaining inner and outer surface stress data of one or more grid cells in the finite element model of the subframe structure from the CAE simulation analysis results of the subframe under the various working conditions;

[0038] Obtain the subframe test bench durability performance EXCEL template file;

[0039] Determine whether the stress directions of the inner and outer surfaces of the same grid unit in the subframe durability performance EXCEL template file and the subframe CAE simulation analysis results are consistent;

[0040] For grid cells with the same direction, the subframe durability performance is automatically analyzed according to the requirements of the subframe durability performance EXCEL template file, and the subframe life or damage value under various working conditions is generated.

[0041] Furthermore, the subframe test bench durability performance EXCEL template file includes inner and outer surface stress values, inner and outer surface stress directions, material information, durability target values, and subframe life or damage conditions corresponding to the inner and outer surface stress values ​​of one or more grid cells in the subframe structure finite element model.

[0042] Compared with the prior art, the present invention has the following beneficial effects:

[0043] The present invention proposes an automated modeling and analysis method for the durability performance of a subframe bench based on CAE simulation analysis, and uses a pre-built TCL scripting language automation program to realize the automation of subframe weld modeling, the automated establishment of the local coordinate system of all connection hard points of the subframe and the simulated bushing, and the automated creation of the durability analysis load and analysis step, which effectively reduces the labor intensity of the CAE analysis process and greatly improves the work efficiency and modeling accuracy. The present invention is also based on the TCL scripting language, using a subframe bench durability performance EXCEL template containing the inner and outer surface stress data of one or more grid cells in the finite element model of the subframe structure under various working conditions, to realize the automated analysis of the subframe bench durability performance, greatly improve the work efficiency and the standardization of the fatigue durability analysis of the enterprise bench, and can quickly and accurately obtain the subframe bench durability performance analysis results.

[0044] The TCL scripting language automated program creation method of the present invention is mainly based on the automated program writing of the computer language of CAE simulation analysis software. On the one hand, it can quickly improve the modeling efficiency, and on the other hand, it can avoid errors generated in manual operations and the loss of working time caused by searching and correcting errors. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 The figure shows a schematic diagram of the steps of a method for automatic modeling and analysis of the durability performance of a subframe bench based on CAE simulation analysis proposed by the present invention;

[0046] Figure 2 Shown is a front view of a sub-frame connection hard point in an embodiment of the present invention;

[0047] Figure 3 Shown is a schematic diagram of the back side of the sub-frame connection hard point in an embodiment of the present invention;

[0048] Figure 4 The figure shows a schematic diagram of an EXCEL template file for connecting hard point coordinates and local coordinate system direction coordinates in an embodiment of the present invention;

[0049] Figure 5 The figure is a schematic diagram of the loading result of the CAE analysis load step automation program in an embodiment of the present invention;

[0050] Figure 6 The figure shows a schematic diagram of the result of loading the automatic program of the CAE analysis step in an embodiment of the present invention;

[0051] Figure 7 The figure shows a schematic diagram of an EXCEL template file of the durability performance of a sub-frame test bench according to an embodiment of the present invention;

[0052] Figure 2 , Figure 3 Among them, 1-the first body connection hard point, 2-the second body connection hard point, 3-the steering gear connection hard point, 4-the stabilizer bar connection hard point, 5-the control arm front connection hard point, 6-the control arm rear connection hard point. DETAILED DESCRIPTION

[0053] The technical solution of the present invention is described in detail below through the accompanying drawings and specific embodiments. It should be understood that the embodiments of the present invention and the specific features in the embodiments are detailed descriptions of the technical solution of the present invention, rather than limitations on the technical solution of the present invention. The embodiments of the present invention and the technical features in the embodiments may be combined with each other unless there is a conflict.

[0054] This embodiment introduces an automatic modeling and analysis method for the durability performance of a subframe test bench based on CAE simulation analysis. Figure 1 As shown, the specific steps include:

[0055] Step A: Prepare a detailed subframe CAD digital model based on the subframe information. The subframe CAD digital model needs to include parameter information such as the thickness of each part of the subframe, material information, weld connection information, bolt connection information, and connection position information (i.e., connection hard point information) of the subframe and the vehicle body mounting point.

[0056] Step B: Use the CAE finite element simulation analysis software HYPERMESH to perform structural meshing on each component of the subframe CAD digital model and build a subframe CAE mesh structure finite element model. The complete subframe CAD digital model data parameter input can greatly improve the modeling efficiency of the subframe bench durability performance analysis. The subframe CAE mesh structure finite element model includes each part of the subframe, but there is a lack of connection between the parts.

[0057] Step C: according to the weld connection information in the sub-frame CAD digital model, the TCL script language automation program is used to perform weld automatic modeling on the basis of the sub-frame CAE mesh structure finite element model to obtain a weld simplified model.

[0058] Step C01, obtain the TCL script language automation program for weld automation modeling, part of the core code of which is as follows:

[0059]

[0060] Step C02: extract the center line of the weld geometry according to the weld connection information in the subframe CAD digital model.

[0061] Step C03, run the TCL script language automation program, select the center line of the weld geometry, and automatically connect two adjacent parts in the sub-frame CAE grid structure finite element model through the automation program to obtain a simplified weld model. The simplified weld model is loaded on the sub-frame CAE grid structure finite element model.

[0062] Step D: Use the TCL scripting language automation program and the preset EXCEL template file of the connection hard point coordinates and the local coordinate system direction coordinates to automatically establish the connection hard point local coordinate system and the bushing BEAM unit. Among them, the BEAM unit is a finite element analysis unit in the CAE finite element simulation analysis software HYPERMESH, which is often used to simulate long strip components.

[0063] Step D01: According to the connection position of the subframe and the vehicle body mounting point in the subframe CAD digital model, the coordinates of each connection hard point in the subframe are obtained. Figure 2 , Figure 3 shown.

[0064] Step D02: Obtain the coordinates of the two end points of the connecting bushing (i.e., the two end points of the bushing BEAM unit) and the corresponding local coordinate system direction coordinates according to the CAD digital model of the subframe, and generate an EXCEL template file of the connecting hard point coordinates and the local coordinate system direction coordinates in combination with the connecting hard point coordinates of step D01.

[0065] In the embodiment of the present invention, Figure 4 As shown in the figure, the EXCEL template file of the connection hard point coordinates and the local coordinate system direction coordinates contains not only all the connection hard point coordinates, but also the coordinates of the two end points of the bushing BEAM unit and the local coordinate system direction at the connection hard point. Among them, the axial direction is the local coordinate system Z direction, the radial direction is the local coordinate system X direction, and the Y direction is determined according to the right-hand screw rule.

[0066] Step D03: Obtain a TCL scripting language automation program for establishing a local coordinate system and simulating a bushing. The TCL scripting language automation program can be written according to actual needs.

[0067] Step D04: determine whether the connection hard point coordinates and the local coordinate system direction coordinates of the EXCEL template file are consistent with the connection hard point coordinates in the subframe CAE mesh structure finite element model or whether the distance tolerance is less than the predetermined tolerance, and at the same time determine whether the connection hard point coordinates and the local coordinate system direction coordinates of the EXCEL template file are consistent with the two end point coordinates of the bushing BEAM unit in the subframe CAE mesh structure finite element model or whether the distance tolerance is less than the predetermined tolerance. The predetermined tolerance is set manually according to actual conditions.

[0068] Step D05: If the result of step D04 is that the coordinate positions are consistent or the distance tolerance is less than the predetermined tolerance, run the TCL script language automation program according to the EXCEL template file of the connection hard point coordinates and the local coordinate system direction coordinates to automatically establish the connection hard point local coordinate system and the bushing BEAM unit.

[0069] In the embodiment of the present invention, the bushings include bushings at subframe and vehicle body mounting points, bushings at powertrain suspension mounting points, bushings at control arms and connecting rods, stabilizer bar bushings, and the like.

[0070] Step E: Use the beam unit and various spring units in the CAE simulation analysis software to simplify the existing subframe suspension system model to obtain a simplified suspension system model. Assign attributes to the simplified suspension system model based on the test data to complete the construction of simplified models of each part. 3D solid mesh units are used for control arms, steering gears, connecting rods, stabilizer bars, etc., and spring units are used for rubber bushings, springs, etc.

[0071] For the simplified model of the rubber bushing: the nonlinear stiffness of the rubber bushing in six directions is tested experimentally, and the full stiffness data is interpolated outward for those with insufficient measurement range; the limit of the bushing in each direction in the system is measured according to the part size and assembly relationship; the equivalent stiffness curve of the bushing in each direction is obtained based on the above measurement data, and the equivalent stiffness curve of the bushing in each direction is associated with its corresponding spring unit and assigned as unit attribute.

[0072] For the simplified spring model: the spring stiffness is measured according to the test, and the spring preload is calculated according to the vehicle weight parameter. The equivalent stiffness curve of the spring is obtained and assigned as the unit attribute.

[0073] Step F, connect the subframe parts in the finite element through connection models such as welding point units (from CAE simulation analysis software), weld simplified models, bolt simplified models (which can be obtained by modeling through existing means) and bushing BEAM units, improve the subframe CAE grid structure finite element model, and obtain a complete subframe structure finite element model.

[0074] Step G: Before performing the subframe bench durability performance analysis, it is necessary to add loads and constraints to the subframe structure finite element model. The present invention automatically sets the load nodes, load steps and analysis steps of the subframe structure finite element model through the pre-built CAE load node and load step automation program and analysis step automation program to obtain the subframe bench durability performance analysis finite element model.

[0075] In the embodiment of the present invention, the subframe test bench durability performance analysis automated modeling program mainly includes two contents: CAE load node and load step automated program writing, and analysis step automated program writing.

[0076] The automatic program writing of CAE load nodes and load steps includes: first setting the load point number; then creating six node sets for the six degrees of freedom directions of the load point; then assigning node numbers through the computer loop language of the CAE simulation analysis software, and then writing the corresponding analysis loads of the nodes in the six node sets, that is, realizing the automatic program writing of load nodes and load steps by defining the load amplitude or load curve in each direction of each node, thereby realizing the automatic creation of all load nodes and load steps.

[0077] The CAE analysis step automation program writing includes: firstly, associating the load amplitude or load curve created above with the corresponding analysis step, then defining the analysis type and analysis output result type of the subframe bench durability analysis, and finally realizing the creation of analysis steps in all directions of all connection hard points through the computer loop language of the CAE simulation analysis software.

[0078] The CAE analysis load step automation program and the loading results of the CAE analysis step automation program are as follows Figure 5 , Figure 6 shown.

[0079] Step H, based on the subframe bench durability performance analysis finite element model obtained in step G, by modifying the load amplitude or load curve, obtain the subframe bench durability performance analysis finite element model under different working conditions, and then perform CAE simulation analysis and calculation on the subframe under each working condition, and output the subframe CAE simulation analysis results under each working condition according to preset evaluation requirements, wherein the subframe CAE simulation analysis results include the inner and outer surface stress data of one or more grid cells in the subframe structure finite element model.

[0080] The subframe structure finite element model includes multiple grid units. The stress, strain and displacement data of each grid unit under each working condition can be obtained through CAE simulation analysis and calculation; the grid unit with the maximum stress under each working condition, or the grid unit with stress greater than the preset threshold and the maximum principal stress (absolute value) direction under different working conditions is selected to form a grid unit set, where the preset threshold is the maximum stress multiplied by A%, and the value A is selected according to the actual situation; according to the stress data of each grid unit in the grid unit set, the CAE simulation analysis results of the subframe under each working condition are obtained

[0081] Step I: Input the CAE simulation analysis results of the subframe under various working conditions into a pre-built subframe bench durability performance EXCEL template file, analyze the subframe bench durability performance, and automatically calculate the life or damage value of the subframe under various working conditions.

[0082] Step I01: Construct a subframe durability performance EXCEL template file based on historical subframe durability performance analysis data. Figure 7 As shown, the subframe bench durability performance EXCEL template file includes the inner and outer surface stress values, inner and outer surface stress directions, material information, durability target values, and subframe life or damage conditions corresponding to the inner and outer surface stress values ​​of each grid unit in the subframe structure finite element model.

[0083] Step I02, according to the CAE simulation analysis results output in step H, the inner and outer surface stress data of one or more grid cells under each working condition of the subframe bench are obtained, and then it is determined whether the inner and outer surface stress directions of the same grid cells in the subframe bench durability performance EXCEL template file and the subframe CAE simulation analysis results are consistent. For grid cells with consistent directions, the subframe bench durability performance is automatically analyzed according to the requirements of the subframe bench durability performance EXCEL template, thereby automatically generating the subframe life or damage value under each working condition.

[0084] The present invention uses a pre-built TCL scripting language automation program to realize the automation of subframe weld modeling, the automatic establishment of the local coordinate system of all connection hard points of the subframe and the simulation bushing, and the automatic creation of durability analysis loads and analysis steps, which effectively reduces the labor intensity of the CAE analysis process and greatly improves the work efficiency and modeling accuracy. The present invention is also based on the TCL scripting language, using the subframe bench durability performance EXCEL template containing the inner and outer surface stress data of each grid unit in the finite element model of the subframe structure under various working conditions, to realize the automated analysis of the subframe bench durability performance, greatly improve the work efficiency and the standardization of the fatigue durability analysis of the enterprise bench, and can quickly and accurately obtain the subframe bench durability performance analysis results.

[0085] The TCL scripting language automated program creation method of the present invention is mainly based on the automated program writing of the computer language of CAE simulation analysis software. On the one hand, it can quickly improve the modeling efficiency, and on the other hand, it can avoid errors generated in manual operations and the loss of working time caused by searching and correcting errors.

[0086] It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0087] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0088] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0089] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0090] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the enlightenment of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the purpose of the present invention and the claims, which all fall within the protection of the present invention.

Claims

1. An automated modeling and analysis method for subframe durability performance based on CAE simulation analysis, characterized in that: The steps include: Use CAE simulation analysis software to divide the structural mesh of each component of the subframe CAD digital model and build the subframe CAE mesh structure finite element model; Using TCL scripting language automation program to automatically model the weld seam based on the subframe CAE grid structure finite element model, a simplified weld seam model was obtained; Using the TCL scripting language automation program, the local coordinate system of the connection hard point and the bushing BEAM unit are established according to the preset EXCEL template file of the connection hard point coordinates and the local coordinate system direction coordinates; Connect the parts in the sub-frame CAE grid structure finite element model through welding point units, weld simplified models, bolt simplified models and bushing BEAM units to generate a complete sub-frame structure finite element model; The subframe structure finite element model is automatically modeled with load nodes, load steps and analysis steps through the pre-built CAE load node and load step automation program and analysis step automation program, and the subframe bench durability performance analysis finite element model is obtained; By modifying the load amplitude or load curve of the subframe bench durability performance analysis finite element model, the subframe CAE bench durability performance simulation analysis under various working conditions is performed to obtain the subframe CAE simulation analysis results under various working conditions, wherein the subframe CAE simulation analysis results include the stress, strain and displacement of the subframe; The CAE simulation analysis results of the subframe under various working conditions are input into the pre-built subframe bench durability performance EXCEL template file to obtain the life or damage value of the subframe under various working conditions; The method of using the TCL scripting language automation program to automatically model the weld based on the CAE grid structure finite element model of the subframe to obtain a simplified weld model includes: Get the TCL scripting language automation program for weld seam automation modeling; Obtain the weld connection information based on the subframe CAD digital model and obtain the center line of the weld geometry; By running the TCL scripting language automation program, the center line of the weld geometry is selected to automatically generate the weld connecting two adjacent parts in the subframe CAE grid structure finite element model to obtain a simplified weld model; The subframe CAE simulation analysis results under various working conditions are input into a pre-built subframe bench durability performance EXCEL template file to obtain the life or damage value of the subframe under various working conditions, including: Obtaining inner and outer surface stress data of one or more grid cells in the finite element model of the subframe structure from CAE simulation analysis results of the subframe under the various working conditions; Obtain the subframe test bench durability performance EXCEL template file; Determine whether the stress directions of the inner and outer surfaces of the same mesh unit in the subframe bench durability performance EXCEL template file and the subframe CAE simulation analysis results are consistent; For grid cells with the same direction, the subframe durability performance is automatically analyzed according to the subframe durability performance EXCEL template file requirements, and the subframe life or damage value under various working conditions is generated; The subframe bench durability performance EXCEL template file includes inner and outer surface stress values, inner and outer surface stress directions, material information, durability target values, and subframe life or damage conditions corresponding to the inner and outer surface stress values ​​of each grid unit in the subframe structure finite element model.

2. The method for automatic modeling and analysis of subframe durability performance based on CAE simulation analysis according to claim 1 is characterized in that: The EXCEL template file of the connection hard point coordinates and the local coordinate system direction coordinates includes the coordinates of all the connection hard points between the subframe and the vehicle body, the coordinates of the end points of the bushing BEAM unit and the local coordinate system direction coordinates of the connection hard points.

3. The method for automatic modeling and analysis of subframe durability performance based on CAE simulation analysis according to claim 2 is characterized in that: Using the TCL scripting language automation program, according to the preset EXCEL template file of the connection hard point coordinates and the local coordinate system direction coordinates, the local coordinate system of the connection hard point and the bushing BEAM unit are established, including: According to the connection position information of the subframe and the vehicle body mounting points in the subframe CAD digital model, the coordinates of each connection hard point in the subframe are obtained; Obtain the coordinates of both end points of the bushing BEAM unit and the corresponding local coordinate system direction coordinates according to the CAD digital model of the subframe, and generate an EXCEL template file connecting the hard point coordinates and the local coordinate system direction coordinates; Get the TCL scripting language automation program for establishing local coordinate system and bushing BEAM unit; Determine whether the connection hard point coordinates and local coordinate system direction coordinates in the EXCEL template file are consistent with the connection hard point coordinates in the subframe CAE mesh structure finite element model or whether the distance tolerance is less than the predetermined tolerance, and determine whether the two end point coordinates of the bushing BEAM unit in the two are consistent or whether the distance tolerance is less than the predetermined tolerance; If the coordinates are consistent or the distance tolerance is less than the preset tolerance, the TCL script language automation program is run according to the EXCEL template file of the connection hard point coordinates and the local coordinate system direction coordinates to automatically establish the local coordinate system of the connection hard point and the bushing BEAM unit.

4. The method for automatic modeling and analysis of subframe durability performance based on CAE simulation analysis according to claim 1 is characterized in that: The load nodes and load steps of the subframe bench finite element model are automatically set through the pre-built CAE load node and load step automation program, including: Set the load node number; Create six node sets for each load node in the six degrees of freedom directions; The node numbers are assigned through the computer loop language of the CAE simulation analysis software, and the corresponding analysis loads of each node are written by defining the load amplitude or load curve in each direction of each node, thereby obtaining the load nodes and load steps.

5. The method for automatic modeling and analysis of subframe durability performance based on CAE simulation analysis according to claim 4 is characterized in that: The analysis steps of the subframe bench finite element model are automatically set up through pre-built analysis step automation procedures, including: Associate the created load amplitude or load curve with the corresponding analysis step; Define the analysis type and analysis output result type of the subframe bench durability analysis; The computer cycle language of CAE simulation analysis software automatically creates analysis steps in all directions of all connection hard points.

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