Rail transit vehicle composite material structure virtual analysis method and system

Abstract

The application provides a kind of rail transit vehicle composite material structure virtual analysis method and system, belong to rail transit technical field.The virtual method includes: according to the basic provision made to the physical and mechanical characteristics of rail transit structure characteristics and composite material, virtual model establishment rule method, material parameter characterization acquisition method and test matrix, load boundary application method, virtual model checking method, strength analysis process, result output and result evaluation.The application realizes the virtual analysis verification and output evaluation of rail transit composite material structure, solves the problem of low result simulation precision of large composite material rail transit equipment, verifies the accuracy to reach the engineering requirement, effectively increases the one-time passing probability of full-size strength test, reduces the development test cost.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of rail transit, and particularly relates to a rail transit vehicle composite material structure virtual analysis method and system BACKGROUND

[0002] Carbon fiber composite material has excellent properties such as high strength, high modulus, corrosion resistance, fatigue resistance, and strong designability, and is an excellent choice for solving the contradictions between high speed and energy consumption and low carbon, light weight and safety and large load in rail transit, and realizing vehicle lightweighting. On the one hand, lightweighting reduces the self weight of the vehicle body, saves raw materials and reduces manufacturing costs. On the other hand, lightweighting reduces the traction and braking forces of the vehicle, realizes energy saving and consumption reduction, reduces vehicle vibration energy, reduces noise inside and outside the vehicle, reduces wheel-rail wear, reduces maintenance amount, and the like, thereby saving operation cost, effectively reducing operation energy consumption and life cycle cost. In addition, the application difficulties of traditional metal materials such as corrosion, fatigue fracture, local buckling, and welding deformation can also be effectively solved.

[0003] However, the inventors have found that the heterogeneity and anisotropy of composite materials are different from those of traditional metal structures, and the composite material structure is complex due to material, process, size, and failure mode, and its material mechanics and physical parameters, material characterization, modeling program, analysis and verification process, virtual verification accuracy and result output evaluation, and the like are different from those of metal structures. Therefore, the current design, analysis and verification of rail transit composite material structures rely more on experience and physical tests, and the strength analysis method of metal structures is still used, and the analysis reliability and accuracy cannot meet the engineering requirements, which seriously affects the design optimization research and development and verification period of rail transit composite materials.

[0004] Patent No. CN107766640A discloses a finite element modeling method for microstructure particle reinforced composite materials, which is a finite element modeling method for particle reinforced composite materials and does not involve continuous fiber reinforced composite materials. It is a modeling method for microstructure and cannot guide the strength analysis and verification of continuous fiber composite material structures of engineering equipment.

[0005] Patent No. CN111382477B discloses a composite material wallboard analysis method based on structural genome technology, which deduces the mechanical properties of the macrostructure of the composite material through the mechanical properties of the matrix and the fibers. It does not involve the engineering strength verification analysis method, evaluation method and material parameter acquisition of the rail transit composite material structure and other key technologies. SUMMARY

[0006] In view of the deficiencies of the prior art, the purpose of the present application is to provide a rail transit vehicle composite material structure virtual analysis method and system, which solves the problem of low simulation precision of large composite material rail transit equipment, verifies and evaluates the precision to meet the engineering requirements, effectively increases the one-time passing probability of full-size strength test, and reduces the research and development test cost.

[0007] In order to achieve the above-mentioned purpose, the present application is realized by the following technical solutions:

[0008] In the first aspect, the present application provides a rail transit vehicle composite material structure virtual analysis method, comprising the following processes:

[0009] The requirements of the rail transit equipment composite material structure virtual analysis are configured, including: configuring the basic requirements, the unit system and the coordinate system;

[0010] The virtual analysis model is established according to the rail transit vehicle composite material structure parameters, including: constructing the geometric topology model, selecting the element type and the element order, configuring the grid density, performing the grid division, configuring the attribute, configuring the failure criterion, and applying the load boundary condition;

[0011] According to the virtual analysis model, the virtual test of the rail transit composite material structure is performed and the virtual test result is generated.

[0012] As an optional implementation mode, the basic requirements are configured, including:

[0013] The shell element is selected for the thin plate or thin shell composite material structure; the solid element is adopted for the thick plate structure or the structure needing to analyze the interlayer stress, and the element number along the thickness direction meets the set threshold value;

[0014] On the premise that the finite element analysis precision of the concerned part is greater than or equal to the set value, the geometric model details of the structure are simplified;

[0015] According to the mechanical product geometric model, the attribute, the load and the constraint characteristics, and the type and purpose of the finite element analysis, the type of the element is selected;

[0016] The stress slowly changing area is coarsened, and the stress sharply changing area is refined; the non-concerned area is coarsened, and the concerned area is refined;

[0017] According to the analysis type and the test result, the building block method is adopted to analyze the model and evaluate the calculation result;

[0018] When the continuous fiber direction change is greater than the set degree, the laying simulation is performed to correct the layer angle.

[0019] As an optional implementation mode, the coordinate system is configured, including:

[0020] The coordinate system is determined by the right-hand rule, and Cartesian coordinate system, cylindrical coordinate system or spherical coordinate system is adopted. When modeling by finite element analysis, the global coordinate system should be defined. When the modeling, load, constraint or result display requirement is inconsistent with the global coordinate system, the local coordinate system is added;

[0021] The global coordinate system referred to by the geometric model is configured, so that the position and direction of the part after the numerical model is imported into the analysis software are consistent with those in the drawing software;

[0022] The local coordinate system is configured to represent the orientation of a laminate layer. The x-axis of the local coordinate system points to the fiber direction of the 0° layer of the laminate, the z-axis is consistent with the stacking direction of the layer, and the y-axis is determined according to the right-hand rule.

[0023] The material coordinate system is configured. The x-axis of the material coordinate system in each single layer is consistent with the fiber direction of the layer, the z-axis is consistent with the stacking direction of the laminate, and the y-axis is determined by the right-hand rule. The material coordinate system is determined by the stacking direction, the layer angle and the layer reference coordinate system.

[0024] As an optional implementation, the geometric topology model is constructed, including:

[0025] The geometric model is established in a 1:1 proportional relationship. For structures with a slenderness ratio greater than 8, the middle axis is selected for construction. For structures with a typical structure size to wall thickness ratio greater than 10, the median surface is selected for construction. For structures that are not suitable for line and surface construction and key parts of the structure, solid construction is adopted.

[0026] As an optional implementation, the element type and element order are selected, including:

[0027] For laminated plate structures mainly subjected to in-plane loads and with a length-to-thickness ratio greater than a set value and without the need for interlaminar stress analysis, two-dimensional elements are selected.

[0028] When the normal force on the laminated plate structure cannot be ignored, the transverse shear effect is greater than a set value, or the interlaminar stress or the stress in the local area is concerned, three-dimensional elements are used to meet the solution accuracy;

[0029] For the adhesive layer structure, cohesive elements or viscous contact technology are selected;

[0030] For sandwich structures, three-dimensional elements are selected. If the out-of-plane stress is negligible, two-dimensional elements are used.

[0031] The fastener connection of the composite material is simulated by one-dimensional elements. If the connection is critical, three-dimensional elements are used.

[0032] When the structure shape is irregular, the deformation and stress distribution are complex, high-order elements are selected. High-order elements are preferably selected for regions with a calculation accuracy greater than a set value.

[0033] The selected low-order unit with precision requirement less than the set value, and the connection position of different order units should use transition unit or multi-point constraint.

[0034] As an optional implementation, the grid density is configured, at least including:

[0035] The setting of grid density control is performed on the parts with structural change greater than the set value, curvature change of the curved surface greater than the set value, load change greater than the set value, and different material connection.

[0036] The coarse and fine grid transition adopts triangular element transition or MPC transition, the grid density of the stress response attention area is greater than the grid density of the displacement response attention area, the element size in the main bearing direction is less than the set value, and the element size perpendicular to the direction is slightly enlarged when the quality requirement is met.

[0037] As an optional implementation, the grid division is performed, including:

[0038] The main geometric contour line is reserved during grid division, and the grid is consistent with the geometric contour or the difference is within the set range. For solid element grid, more than three layers in the thickness direction of the structure are ensured, or the number of layers is reduced under the condition of meeting the solving accuracy.

[0039] The symmetric structure should ensure that the layer properties are consistent with the actual structure, and when the laminate exists a lost layer, the grid should be divided according to the lost layer line, so that the unit normal of each part is consistent.

[0040] As an optional implementation, the properties are configured, including: the composite material structure properties include single-layer material properties, single-layer layer thickness, single-layer layer angle, laying direction and layer sequence.

[0041] Further, the single-layer material allowable value test matrix, the sandwich structure test matrix, the adhesive layer material parameter test matrix, the mechanical connection extrusion strength test matrix, the single-layer layer elastic material parameters and the grid quality check standard are configured.

[0042] Further, the single-layer material properties use anisotropic linear elastic material to simulate the material properties of the composite laminate, and the material properties use the single-layer material allowable value, including:

[0043] 0° or warp tensile elastic modulus and strength, 90° or weft tensile elastic modulus and strength, 0° or warp and 90° or weft compression elastic modulus and strength, main Poisson's ratio, longitudinal and transverse shear elastic modulus and strength.

[0044] 0° or warp tensile, compression strength, longitudinal and transverse shear strength of 90° or weft take B reference value, the average value of tensile and compression elastic properties, and the average value of the main Poisson's ratio.

[0045] Further, the determination of the single-level material allowable value includes:

[0046] The B reference value and the A reference value of the strength under different environmental condition combinations are determined;

[0047] The material allowable value of the tensile and compressive strength adopts the statistically processed strength B reference value, in the scheme design and preliminary design stage, if the test sample is less than the set value and the data dispersion is greater than the set value, the value of the material allowable value is taken as 85% of the average value and the value greater than the set value in the B reference value;

[0048] The material allowable value of the in-plane shear strength adopts the statistically processed strength or 1.5 times the yield strength B reference value, and the value less than the set value is taken;

[0049] The limit shear strength B reference value is taken as the material allowable value; when the in-plane shear strength is the key performance, 1.5 times the yield strength B reference value is taken as the material allowable value;

[0050] The material allowable value of the modulus adopts the average value of all test data under each environmental condition.

[0051] As an optional implementation mode, a layer reference coordinate system is defined, the layer angle of each single layer is defined in the layer reference coordinate system, and the deviation between the defined nominal layer angle and the actual layer angle is not more than a set angle;

[0052] The stacking direction and sequence of the layup are defined, the stacking direction of the laminated plate is defined by the unit normal, the unit normal of the same laminated plate region should be consistent and the same as the actual stacking direction, and the layer sequence is defined to be consistent with the actual laminated plate;

[0053] The layer offset is defined, the shell mesh is located in the middle surface of the laminated plate cross section, and the layer attribute effect is ensured to be consistent with the design.

[0054] As an optional implementation mode, the failure criterion is configured, including:

[0055] The strength check of the composite material structure includes the strength check based on the composite material single-layer strength failure theory, and the strength value adopted by the composite material single-layer strength failure theory adopts the material allowable value;

[0056] According to the requirement, the output of the failure criterion and the stress and strain is set, at least including the stress and strain of the dangerous layer and the stress and strain value of the whole laminated plate.

[0057] As an optional implementation mode, the boundary condition is applied, including: the virtual model constraint is applied according to the actual installation condition, the constraint area should accurately reflect the actual constraint condition, the load type is selected according to the standard or actual test load, and the load size, direction and action area are consistent with the actual load condition;

[0058] The mass load should be applied in a concentrated load manner, and the non-load-bearing structure mass is applied in a uniform manner, so that the curb mass and the gravity center position of the vehicle body structure are consistent with the design.

[0059] As an optional implementation, after the load boundary condition is applied, the virtual model is checked, and the grid elements are checked to meet the set value or set range requirement.

[0060] As an optional implementation, according to the virtual analysis model, virtual testing of the rail transit composite material structure is performed, including:

[0061] Determine the material allowable value, and use the material allowable value to perform initial load-carrying capacity analysis;

[0062] According to the load-carrying capacity analysis of the structure in the initial stage, select the key area for subsequent test verification;

[0063] Determine the most critical strength failure mode of each design feature;

[0064] Select a test environment that can produce a strength criticality failure mode;

[0065] Test multiple element-level test samples, each simulating a selected failure mode and loading condition, and compare with analysis prediction;

[0066] Increase the test complexity to evaluate more complex loading conditions and the failure probability of several potential damage modes. Compare the test results with the analysis prediction, and adjust the analysis model or design value as needed;

[0067] Determine and perform full-size component static testing as needed to verify internal loads and structural integrity, and compare with analysis;

[0068] Perform whole-vehicle-level statics finite element analysis, use the determined design value to perform structure ultimate strength checking, and perform strength evaluation of damage coefficient and safety margin.

[0069] As an optional implementation, the virtual test results are generated, including:

[0070] The output results include all or part of the stress, strain and deformation contour maps of the concerned parts;

[0071] The single-layer results of the laminate should be output for global layer identification, so that the results can be tracked by layer;

[0072] According to the laminate failure mode, the corresponding stress and strain values are output, including at least the stress and strain of the dangerous layer and the overall stress and strain of the laminate;

[0073] When the normal force of the laminate structure is not negligible, the transverse shear effect is greater than a set value, or the interlaminar stress or the stress of a local area is concerned, the interlaminar stress value is generated.

[0074] Further, the evaluation of the results is performed, and when the static strength of the composite structure is verified, it is ensured that the structure does not produce harmful deformation and damage under the action of the limit load; under the condition of the limit load and the most severe environment combination, the structure does not have overall damage;

[0075] For the strength evaluation of the limit load, the first layer failure criterion and the limit strain method are used, and the failure of the composite structure includes the failure of the laminate and the sandwich structure, the mechanical connection failure, and the adhesive failure; the failure criterion of the laminate is divided into the failure criterion based on the single-layer strength and the failure criterion based on the limit strain failure of the laminate;

[0076] The evaluation includes the verification and evaluation of the finite element model and the failure criterion, and the static strength evaluation verification, wherein:

[0077] The verification and evaluation of the finite element model and the failure criterion are to check the convergence of the calculation results of the model, analyze the rationality of the stress concentration position, verify the finite element model and the failure criterion according to the block-by-block analysis process, and compare the finite element analysis results with the test results, so as to adjust the finite element analysis model, recalculate and evaluate based on the test results;

[0078] The static strength evaluation verification is to use the verified finite element model and the failure criterion to perform the static strength evaluation verification of the whole vehicle level, and when the static strength result meets the corresponding failure criterion and the design value, the static strength of the structure meets the strength requirement, and the static strength test is performed according to the finite element analysis result.

[0079] The second aspect of the present application provides a virtual analysis system for a composite material structure of a rail transit vehicle.

[0080] The virtual analysis system for a composite material structure of a rail transit vehicle comprises:

[0081] A requirement configuration module is configured to configure requirements for virtual analysis of a composite material structure of rail transit equipment, including configuring basic requirements, unit systems and coordinate systems.

[0082] A model construction module is configured to establish a virtual analysis model according to parameters of a composite material structure of a rail transit vehicle, including constructing a geometric topology model, selecting an element type and an element order, configuring grid density, performing grid division, configuring attributes, configuring a failure criterion, and applying a load boundary condition.

[0083] A virtual analysis module is configured to perform virtual testing of a composite material structure of rail transit according to the virtual analysis model and generate a virtual testing result.

[0084] The third aspect of the present application provides a computer readable storage medium, which stores a program, and the program is executed by a processor to implement the steps of the rail transit vehicle composite material structure virtual analysis method according to the first aspect of the present application.

[0085] The fourth aspect of the present application provides an electronic device, which comprises a memory, a processor and a program stored in the memory and executable on the processor, and the processor implements the steps of the rail transit vehicle composite material structure virtual analysis method according to the first aspect of the present application when executing the program.

[0086] The beneficial effects of the present application are as follows:

[0087] 1. The existing rail transit structure strength virtual analysis method is for metal structure and is not suitable for anisotropic and multi-layer composite material structure. The present application establishes a virtual analysis verification method according to the characteristics of rail transit and composite material, can guide the engineering design optimization and verification of composite material equipment, solves the problem of low simulation precision of large composite material rail transit equipment, verifies the evaluation precision to meet the engineering requirements, effectively shortens the engineering cycle and manufacturing test cost, realizes reliable operation, reduces the probability of failure of full-size static strength test of rail transit equipment, and reduces the research and development cost.

[0088] 2. The rail transit vehicle composite material structure virtual analysis method provided by the present application establishes the basic requirements of rail transit equipment composite material structure strength virtual analysis, establishes the rail transit equipment composite material structure strength virtual analysis model, realizes the rail transit equipment composite material structure strength virtual analysis, realizes the rail transit equipment composite material structure strength result output and evaluation, and can comprehensively analyze the rail transit vehicle composite material structure virtual analysis.

[0089] 3. The rail transit vehicle composite material structure virtual analysis method provided by the present application relates to geometric topology model construction, unit type selection method, unit order selection method, grid density control technology, grid division method, attribute setting technology, failure criterion definition method, boundary condition application and virtual model checking method, and has higher analysis simulation precision.

[0090] 4. The rail transit vehicle composite material structure virtual analysis method provided by the present application sets the test matrix of the physical and mechanical performance parameters of the required materials, ensures the precision of the structure strength virtual analysis under the condition of reducing the test cost, and provides a good foundation for virtual analysis verification and evaluation.

[0091] 5. The rail transit equipment composite material structure strength virtual analysis method provided by the application solves the problem of poor virtual verification precision and inability to meet engineering analysis and verification caused by the anisotropy characteristics of composite materials, manufacturing process uncertainty, load uncertainty, size factor uncertainty, environmental influence factor uncertainty and failure simulation uncertainty.

[0092] 6. The application determines the basic requirements of composite material structure strength result output, ensures the guidance of verifying the rail transit equipment composite material structure strength, and solves the problem of particularly huge and difficult analysis of the composite material structure strength output result.

[0093] 7. The application determines the evaluation method of the composite material structure strength model and failure criterion, solves the problems of complex and uncertain composite material structure modeling and failure criterion applicability, determines the virtual verification method of the rail transit composite material structure static strength, and solves the problem of insufficient virtual verification precision of the rail transit composite material structure strength. BRIEF DESCRIPTION OF DRAWINGS

[0094] The drawings accompanying the specification of the application form a part of the application and serve to further understand the application, the illustrative embodiments of the application and the description thereof serve to explain the application and do not constitute an improper limitation of the application.

[0095] Figure 1 The overall flowchart of the rail transit vehicle composite material structure virtual analysis method provided for the embodiment 1 of the application is shown.

[0096] Figure 2 The flowchart of the geometric topology model construction method provided for the embodiment 1 of the application is shown.

[0097] Figure 3 The flowchart of the specific test method provided for the embodiment 1 of the application is shown.

[0098] Figure 4 The setting diagram of the mesh density control provided for the embodiment 1 of the application is shown.

[0099] Figure 5 The rail transit continuous fiber composite material structure diagram provided for the embodiment 1 of the application is shown.

[0100] Figure 6 The rail transit equipment composite material structure strength result output result diagram provided for the embodiment 1 of the application is shown. Figure 1 .

[0101] Figure 7 The rail transit equipment composite material structure strength result output result diagram provided for the embodiment 1 of the application is shown. Figure 2 .

[0102] Figure 8 The failure mode example schematic diagram provided for embodiment 1 of the present application. DETAILED DESCRIPTION

[0103] It should be noted that the following detailed description is illustrative only and is intended to provide further description of the application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0104] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments consistent with the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof.

[0105] Embodiment 1:

[0106] As introduced in the background, the existing virtual analysis method of rail transit structure strength is for metal structure, and is not suitable for anisotropic and multi-layer composite material structure. Embodiment 1 of the present application provides a virtual analysis method of rail transit vehicle composite material structure, which includes basic regulations made according to the characteristics of rail transit structure and the physical and mechanical characteristics of composite material, virtual model establishment rule method, material parameter representation acquisition method and test matrix, load boundary application method, virtual model checking method, strength analysis flow, result output and result evaluation. Through the above rule method flow, virtual analysis verification and output evaluation of the rail transit composite material structure are realized, and the verification and evaluation accuracy reaches the engineering requirement.

[0107] Specifically, the following processes are included:

[0108] Step 101: Establish the basic requirements of virtual analysis of rail transit equipment composite material structure, including establishing basic requirements, determining unit system and establishing coordinate system.

[0109] The basic requirements in step 101, wherein the preferred implementation method includes:

[0110] Step 101-1: For thin plate or thin shell composite material structure, shell element can be selected to improve calculation efficiency; if the research object is thick plate, or interlaminar stress needs to be analyzed, solid element is used, and there must be enough elements along the thickness direction to capture the stress gradient.

[0111] Step 101-2: Under the premise of ensuring the accuracy of finite element analysis of the concerned parts, the geometric model details of the structure such as corners, small bosses and small grooves are simplified as much as possible.

[0112] Step 101-3: According to the mechanical product geometric model, properties, load and constraint characteristics, and the type and purpose of finite element analysis, the type of element is reasonably selected to ensure the calculation accuracy.

[0113] Step 101-4: Coarse the stress slowly changing area, and refine the stress sharply changing area; coarse the uninterested area (only the area built into the model for force transmission), and refine the interested area.

[0114] Step 101-5: According to the analysis type and test results, the "building block" method is used for analysis model and calculation result evaluation.

[0115] Step 101-6: Considering the fiber direction and thickness difference at each position caused by the change of manufacturing process and geometric surface curvature, when the continuous fiber direction change is greater than 4°, the layer angle is corrected by the laying simulation.

[0116] Steps 101-1 to 101-6 do not have a specific logical order, and only represent the requirement points that need to be included in step 101;

[0117] In step 101, the unit system is determined, and one of the feasible unit systems is shown in Table 1:

[0118] Table 1: Composite virtual analysis unit system of rail vehicle

[0119]

[0120] In step 101, the coordinate system is established, including:

[0121] Step 101-7: The coordinate system is determined by the right-hand rule, and the Cartesian coordinate system is selected, and if necessary, the cylindrical coordinate system or the spherical coordinate system can be selected; when modeling, load, constraint or result display requirements are inconsistent with the global coordinate system, a local coordinate system can be added.

[0122] Step 101-8: The overall coordinate system referred to by the geometric model is established, so that the position and direction of the part after the numerical model is imported into the CAE analysis software (preferably CAE, and other implementation manners can select other analysis software) are consistent with the CAD (preferably CAD, and other implementation manners can select other drawing software).

[0123] Step 101-9: The local coordinate system is established to represent the layer orientation of a laminate, the x-axis of the local coordinate system points to the fiber direction of the 0° layer of the laminate, the z-axis is consistent with the stacking direction of the layer, and the y-axis is determined according to the right-hand rule.

[0124] Step 101-10: Establish the material coordinate system, the x-axis of the material coordinate system in each single layer is consistent with the fiber direction of the layer, the z-axis is consistent with the stacking direction of the laminate, and the y-axis is determined by the right-hand rule; the material coordinate system is determined by the stacking direction, the layup angle, and the layup reference coordinate system.

[0125] Step 102: Establish a virtual analysis model of the composite structure of the rail transit vehicle, and a specific process example is shown in the following Figure 2

[0126] Step 1021: Construct a geometric topology model, and simplify the model as much as possible under the condition of meeting the requirements; a geometric model is established in a 1:1 proportion relationship;

[0127] For structures with a slenderness ratio greater than 8, the intermediate axis is preferably selected for construction; for structures with a typical structure size to wall thickness ratio greater than 10, the median surface is selected for construction, except for interlayer stress; structures that are not suitable for construction using lines and surfaces, as well as key parts of the structure, should be constructed using solids.

[0128] Step 1022: Select a mechanical product unit type according to the structure form of different components; for laminates that mainly bear in-plane loads, have a large length-to-thickness ratio, and do not need to analyze interlayer stress, two-dimensional elements are usually selected;

[0129] When the normal force on the laminate structure cannot be ignored, the transverse shear effect is large, or the interlayer stress and the stress in the local area are concerned, three-dimensional elements should be used to meet the solution accuracy;

[0130] For glue layer structures such as secondary bonding and co-bonding that need to be concerned, cohesive elements or "viscous" contact technology should be selected;

[0131] For sandwich structures, the effect of transverse shear deformation of the structure should be considered, and three-dimensional elements should be selected;

[0132] If the out-of-plane stress can be ignored, two-dimensional elements can be used; the fastener connection of the composite material can be simulated using one-dimensional elements (such as beam elements), and in order to improve the solution accuracy, one-dimensional elements (such as spring elements) that consider the stiffness of the connector should be used, and if the connection is critical, three-dimensional elements should be used;

[0133] When the structure shape is irregular, the deformation and stress distribution are complex, high-order elements are preferably selected. High-order elements are preferably selected for areas with high accuracy requirements;

[0134] Low-order elements can be selected for low accuracy requirements; low-order elements can be selected when the solution accuracy is met, and transition elements or multi-point constraints should be used at the connection positions of different order elements.

[0135] ​Step 1023: setting the grid density control, refining the parts with large structural changes, large curvature changes, large load changes and different material connections;

[0136] The unit size transition should be smooth, and there should be enough units between the coarse and fine grids to avoid large differences in mass and stiffness between adjacent units. The transition between coarse and fine grids should use triangular elements or MPC transition to avoid the paving transition that causes element distortion. As shown in the attached Figure 4 ;

[0137] The grid density of the stress response area of interest should be greater than that of the displacement response area of interest;

[0138] The unit size in the main load-bearing direction should be smaller, and the unit size perpendicular to this direction can be slightly larger when the mass requirement is met;

[0139] The average grid size of the car body is usually around 25mm, the grid size of the stress concentration area such as window corner and door corner is around 10mm, and the grid size of the bogie is around 10mm.

[0140] Step 1024: grid division, keep the main geometric contour lines during grid division, and the grid should be basically consistent with the geometric contour;

[0141] For solid element grids, ensure three layers or more in the thickness direction of the structure, and appropriately reduce the number of layers to meet the solution accuracy. Symmetric structures should be used with caution to ensure that the layer properties are consistent with the actual structure. When there are missing layers in the laminate, the grid should be divided according to the missing layer lines to ensure that the unit normal of each component is consistent.

[0142] Step 1025: property setting, the material property unit should be consistent with the geometric model unit, and the property input information should be accurate and complete;

[0143] It can accurately express the stiffness and mass characteristics of the structure. The properties of composite structures include single-layer material properties, single-layer thickness, single-layer angle, laying direction, and layer sequence.

[0144] The single-layer material properties use anisotropic linear elastic materials to simulate the material properties of composite laminates. The material properties use single-layer material allowable values, including a) 0° (or longitudinal) and 90° (or latitudinal) tensile elastic modulus and strength; b) 0° (or longitudinal) and 90° (or latitudinal) compressive elastic modulus and strength; c) principal Poisson's ratio; d) longitudinal and transverse (in-plane) shear elastic modulus and strength. Among the above properties, the 0° (or longitudinal) and 90° (or latitudinal) tensile, compressive and shear strengths usually take the B reference value, the elastic modulus takes the average value of the tensile and compressive elastic properties, and the principal Poisson's ratio takes the average value.

[0145] The test matrix is set up according to the accuracy and economic feasibility required by the virtual analysis. The test matrix is shown in Table 2. The test standards and test quantities in Table 2 are an example of a test matrix for material parameters required by the virtual analysis.

[0146] Table 2: Test matrix for single-layer material allowable value

[0147]

[0148] The single-layer material allowable value is determined according to the following principles:

[0149] a) Determine the B reference value and A reference value of the strength under different environmental condition combinations (temperature and moisture content).

[0150] b) For the material allowable value of tensile and compressive strength, the statistically processed strength B reference value is usually used in engineering. If the test sample is small and the data is highly dispersed in the scheme design and preliminary design (including detailed preliminary design) stage, the material allowable value is taken as the larger value of 85% of the average value and the B reference value.

[0151] c) For the material allowable value of longitudinal and transverse (in-plane) shear strength, the statistically processed strength or 1.5 times the yield strength B reference value is usually used in engineering. In general, the B reference value of the ultimate shear strength (i.e., the smaller value of the maximum shear strength and the shear stress corresponding to 5% shear strain) is taken as the material allowable value. When the longitudinal and transverse (in-plane) shear strength is a key performance, 1.5 times the yield strength B reference value is taken as the material allowable value.

[0152] d) For the material allowable value of modulus, the average value of all test data under each environmental condition is usually used in engineering.

[0153] The material parameters required for the core material allowable value of the sandwich structure are determined according to the test matrix in Table 3, which represents an example case.

[0154] Table 3: Test matrix for sandwich structure

[0155]

[0156] The material parameters required for determining the adhesive layer material allowable value are determined according to the test matrix in Table 4, which represents an example case.

[0157] Table 4: Test matrix for adhesive layer material parameters

[0158]

[0159] The test matrix for the extrusion strength required for mechanical connection is shown in Table 5, which represents an example case.

[0160] Table 5: Mechanical connection extrusion strength test matrix

[0161]

[0162] The single-layer elastic performance parameters obtained through the above test matrix are shown in Table 6.

[0163] Table 6: Single-layer elastic material parameters

[0164]

[0165] A layer reference coordinate system is defined, and a layer angle is defined for each single layer in the layer reference coordinate system. The deviation between the defined nominal layer angle and the actual layer angle should not exceed 4°.

[0166] The lamination stack direction and sequence are defined. The lamination stack direction of the laminated plate is defined by the unit normal direction. The unit normal directions of the same laminated plate region should be consistent and the same as the actual lamination stack direction. The defined layer sequence should be consistent with the actual laminated plate.

[0167] The layer offset is defined. By default, it is considered that the shell mesh is located in the middle surface of the laminated plate cross section. The layer attribute effect should be consistent with the design.

[0168] Step 1026: Define failure criteria. The strength check of the composite structure usually includes the strength check based on the composite single-layer strength failure theory. The strength value used in the composite single-layer strength failure theory should use the material allowable value determined in step 1025. The failure criteria and the stress and strain output should be set according to the requirements, at least including: the stress and strain of the dangerous layer and the overall stress and strain value of the laminated plate.

[0169] Step 1027: Apply boundary conditions. The constraints of the virtual model are applied according to the actual installation conditions. The constraint area should accurately reflect the actual constraint situation. Single-point constraints should be avoided to prevent stress concentration. The load type is selected according to the standard or actual test load. The load size, direction and action area should conform to the actual load situation. The mass load of hoisting, on-vehicle air conditioning and in-vehicle equipment which has a greater impact on the structural strength should be applied in the form of concentrated load. The mass of non-load-bearing structures such as interior decoration should be loaded in the form of uniform distribution, and the kerb mass and center of gravity position of the vehicle body structure should be consistent with the design.

[0170] Step 1028: Check the virtual model. The grid elements are checked, and the specific checking contents and requirements are as follows:

[0171] a) There should be no distorted grid in the model. The main parameters for grid checking include element direction, aspect ratio, warping degree, skewness, internal angle, etc. The recommended quantitative numerical values of the above parameters during grid division are shown in Table 7.

[0172] b) Ensure high quality of elements in key structural areas, while appropriately reducing the quality of elements in non-key areas.

[0173] c) The mesh size should be such that the results converge.

[0174] Table 7: Grid Quality Inspection Standards

[0175]

[0176] Perform quality characteristic checks, including checking factors that affect the accuracy of calculations such as model mass distribution, total mass, and centroid distribution, and checking whether the mass distribution and centroid of each part of the model after weighting are consistent with the actual state.

[0177] Perform engineering characteristic checks on the finite element model.

[0178] The specific inspection content and requirements are as follows:

[0179] a) Attribute parameter check. Based on the material properties in the mechanical product structural design, the attribute parameters are reviewed to check whether they are consistent with the design, including single-layer mechanical properties, ply name, ply angle, ply thickness, ply direction, and ply reference surface.

[0180] b) Unit type check: Based on the geometric characteristics of the mechanical product, analysis requirements and assembly method, check the unit type to see if the selection of the unit type is consistent with the structural form and connection method.

[0181] c) Unit normal direction check; check the consistency of unit normal directions according to the actual composite material structure's layup direction.

[0182] d) Constraint check: Check the constraints according to the standard or test fixture installation interface to ensure that the constraints are consistent with the standard or installation conditions.

[0183] e) Load check; Based on the product structure and working load conditions, check the load to see if the load type, load object, etc. are consistent with the working load conditions.

[0184] The continuous fiber composite material structure for rail transit determined through the above steps is shown in the attached figure. Figure 5 As shown, attached Figure 5 This is one example.

[0185] Step 103: Perform virtual analysis of composite material structures for rail transit. The specific steps are as follows:

[0186] Step 1031: Determine the allowable material values ​​and use them for initial load-bearing capacity analysis;

[0187] Step 1032: Select critical areas for follow-up testing verification according to the bearing capacity analysis of the initial stage structure;

[0188] Step 1033: Determine the most critical strength failure mode of each design feature, an example of failure mode is shown in Figure 8

[0189] Step 1034: Select test environment that can produce the strength critical failure mode. Special attention should be paid to failure modes sensitive to the substrate (such as compression, out-of-plane shear and adhesion) and potential risk areas caused by out-of-plane load or stiffness mutation.

[0190] Step 1035: Test multiple element-level test samples, each simulating a selected failure mode and loading condition, compare with analytical predictions, and adjust analytical models or design values as necessary.

[0191] Step 1036: Increase test complexity to evaluate more complex loading conditions and failure likelihood of several potential damage modes; compare test results with analytical predictions, and adjust analytical models or design values as necessary.

[0192] Step 1037: Determine (including compensation factors) and perform full-size component static tests as necessary to verify internal loads and structural integrity, and compare with analysis.

[0193] Step 1038: Perform statics finite element analysis at the vehicle level, use the determined design values to check the structural ultimate strength, and perform strength evaluation of the damage factor and safety margin, etc.

[0194] Step 104: Output and evaluation of composite material structure strength results of rail transit equipment. An example of output results is shown in Figure 6 and Figure 7 .

[0195] Output the strength results, and at least the following information should be extracted and output:

[0196] a) The output results should include all or part of the stress, strain and deformation contour maps of the areas of interest;

[0197] b) The laminate single-layer results output should be identified globally, so that the results can be tracked by layer;

[0198] c) The corresponding stress and strain values should be output according to the laminate failure mode, at least including the stress and strain of the dangerous layer and the overall stress and strain of the laminate;

[0199] ​d) When the normal force on the laminate structure is not negligible, the transverse shear effect is large, or the interlaminar stress and the stress in the local area are concerned, the interlaminar stress value should be output.

[0200] The evaluation of the results is performed, and when the static strength of the composite structure is verified, it is ensured that the structure does not produce harmful deformation and damage under the action of the limit load; under the limit load and the corresponding most severe environmental combination condition, the structure does not occur overall failure, and for the strength evaluation of the limit load, the first layer failure criterion and the limit strain method are used.

[0201] The failure of the composite structure mainly includes the failure of the laminate and the sandwich structure, the mechanical connection failure, and the adhesive failure; the failure criterion of the laminate is divided into the failure criterion based on the single-layer strength and the failure criterion based on the limit strain failure of the laminate.

[0202] The evaluation includes the verification and evaluation of the finite element model and the failure criterion, and the verification and evaluation of the static strength, wherein the verification and evaluation of the finite element model and the failure criterion are to check the convergence of the model calculation results, analyze the rationality of the stress concentration position, verify the finite element model and the failure criterion according to the step 103, compare the finite element analysis results with the test results, and adjust the finite element analysis model according to the test results to recalculate and evaluate.

[0203] The verification and evaluation of the static strength are: using the verified finite element model and the failure criterion to perform the vehicle-level finite element static strength evaluation verification, when the static strength result meets the corresponding failure criterion and the design value, the static strength of the structure meets the strength requirement, and the static strength test can be performed according to the finite element analysis result to increase the reliability of one-time passing of the full-size test.

[0204] Embodiment 2

[0205] The embodiment 2 of the present application provides a virtual analysis system for a composite material structure of a rail transit vehicle, comprising:

[0206] A requirement configuration module is configured to configure requirements for virtual analysis of a composite material structure of rail transit equipment, including: configuring basic requirements, unit system and coordinate system;

[0207] A model construction module is configured to establish a virtual analysis model according to parameters of a composite material structure of a rail transit vehicle, including: constructing a geometric topology model, selecting an element type and an element order, configuring grid density, performing grid division, configuring attributes, configuring a failure criterion, and applying a load boundary condition;

[0208] A virtual analysis module is configured to perform virtual testing of a composite material structure of rail transit according to the virtual analysis model and generate virtual testing results.

[0209] The specific working method of the system is the same as the virtual analysis method of the composite material structure of the rail transit vehicle provided in Embodiment 1, and will not be described here.

[0210] Embodiment 3

[0211] Embodiment 3 of the present application provides a computer readable storage medium, which stores a program, and the program is executed by a processor to implement the steps in the virtual analysis method of the composite material structure of the rail transit vehicle according to Embodiment 1.

[0212] Embodiment 4

[0213] Embodiment 4 of the present application provides an electronic device, which includes a memory, a processor, and a program stored in the memory and executable on the processor, and the processor implements the steps in the virtual analysis method of the composite material structure of the rail transit vehicle according to the first aspect of the present application when executing the program.

[0214] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can take the form of a hardware embodiment, a software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer usable storage media (including but not limited to disk storage and optical storage, etc.) containing computer usable program code.

[0215] The present application is described with reference to flowcharts and / or block diagrams of the method, device (system), and computer program product according to the embodiments of the present application. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, and the combination of the flows and / or blocks in the flowcharts and / or block diagrams can be implemented by computer program instructions. These computer program instructions can be provided to a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to produce a machine, so that the instructions executed by the computer or other programmable data processing devices produce a device that implements the functions specified in the flowcharts and / or block diagrams. Figure 1 The functions specified in one or more flows and / or blocks Figure 1 The functions specified in one or more flows and / or blocks

[0216] These computer program instructions can also be stored in a computer readable storage medium that can guide the computer or other programmable data processing devices to work in a specific way, so that the instructions stored in the computer readable storage medium produce a product including instruction devices that implement the functions specified in the flowcharts and / or block diagrams. Figure 1 The functions specified in one or more flows and / or blocks Figure 1 The functions specified in one or more flows and / or blocks

[0217] These computer program instructions can also be loaded into a computer or other programmable data processing device, so that a series of operational steps are performed on the computer or other programmable data processing device to generate a computer-implemented process, thus the instructions executed on the computer or other programmable data processing device provide a process for implementing the functions specified in the flowchart Figure 1 one flow or multiple flows and / or the functions specified in the block Figure 1 one block or multiple blocks.

[0218] Those of ordinary skill in the art can understand that all or part of the flow of the above-mentioned embodiment method can be completed by instructing the relevant hardware through a computer program, and the program can be stored in a computer-readable storage medium. When the program is executed, it can include the flow of the above-mentioned embodiment of each method. The storage medium can be a magnetic disc, an optical disc, a read-only memory (ROM), a random access memory (RAM), and the like.

[0219] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A virtual analysis method for composite structures of rail transit vehicles, characterized by comprising the following processes: configuring requirements for virtual analysis of composite structures of rail transit equipment, including configuring basic requirements, unit system, and coordinate system; establishing a virtual analysis model according to parameters of composite structures of rail transit vehicles, including constructing a geometric topology model, selecting a unit type and a unit order, configuring grid density, performing grid division, configuring attributes, configuring failure criteria, and applying load boundary conditions; performing virtual testing of composite structures of rail transit vehicles according to the virtual analysis model and generating virtual testing results, including: determining material allowable values and performing initial load capacity analysis using the material allowable values; selecting key areas for subsequent testing verification according to load capacity analysis of the structure in the initial stage; determining the most critical strength failure mode of each design feature; selecting a test environment that can produce a strength criticality failure mode; testing multiple element-level test samples, each simulating a selected failure mode and loading condition, and comparing with analysis prediction; increasing test complexity to evaluate more complex loading conditions and failure possibilities of several potential damage modes; comparing test results with analysis prediction and adjusting analysis model or design values as needed; determining and performing full-size component static testing as needed to verify internal load and structural integrity and comparing with analysis; performing whole-vehicle-level static finite element analysis, using determined design values to perform structure ultimate strength checking and strength evaluation of damage coefficient and safety margin; and outputting results including all or part of stress, strain, and deformation contour maps of the concerned parts; the single-layer results of the laminate are output for global ply identification, so that the results can be tracked by layer; corresponding stress and strain values are output according to the failure mode of the laminate, including at least stress and strain values of the dangerous layer and the whole laminate; when the normal force on the laminate structure cannot be ignored, the transverse shear effect is greater than a set value, or the interlaminar stress or the stress of a local area is concerned, the interlaminar stress value is generated.

2. The virtual analysis method for composite structures of rail transit vehicles according to claim 1, characterized by: configuring basic requirements, including: selecting a shell element for a thin plate or shell composite structure; using a solid element for a thick plate structure or a structure that needs to analyze interlaminar stress, and the number of elements along the thickness direction meets a set threshold; simplifying geometric model details of the structure on the premise that the finite element analysis accuracy of the concerned parts is greater than or equal to a set value; selecting a type of element according to the characteristics of the geometric model, attributes, load, and constraints of the mechanical product, as well as the type and purpose of finite element analysis; coarsening stress slowly changing areas and refining stress sharply changing areas; coarsening non-concerned areas and refining concerned areas; using a building block method to analyze the model and evaluate the calculation results according to the analysis type and test results; and performing a layup simulation to correct the ply angle when the continuous fiber direction changes by more than a set number of degrees.

3. The virtual analysis method for composite structures of rail transit vehicles according to claim 1, characterized by: configuring a coordinate system, including: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The coordinate system is determined by the right-hand rule, and Cartesian coordinate system, cylindrical coordinate system or spherical coordinate system is adopted. When modeling by finite element analysis, the global coordinate system should be defined. When the modeling, load, constraint or result display requirements are inconsistent with the global coordinate system, the local coordinate system is added; The global coordinate system referred to by the geometric model is configured to make the position and direction of the part consistent with the drawing software after the numerical model is imported into the analysis software; The local coordinate system is configured to represent the orientation of a laminate. The x-axis of the local coordinate system points to the fiber direction of the 0° ply of the laminate, the z-axis is consistent with the stacking direction of the ply, and the y-axis is determined according to the right-hand rule. The material coordinate system is configured. The x-axis of the material coordinate system in each single layer is consistent with the fiber direction of the layer, the z-axis is consistent with the stacking direction of the laminate, and the y-axis is determined by the right-hand rule. The material coordinate system is determined by the stacking direction, ply angle and ply reference coordinate system.

4. The virtual analysis method of the composite material structure of the rail transit vehicle according to claim 1, characterized in that: a geometric topology model is constructed, including: a geometric model is established in a 1:1 proportional relationship. For a structure with a slenderness ratio greater than 8, a middle axis is selected for construction. For a structure with a typical structure size and a wall thickness ratio greater than 10, a median surface is selected for construction. For structures that are not suitable for construction by lines and surfaces, and key parts of the structure, a solid is constructed.

5. The virtual analysis method of the composite material structure of the rail transit vehicle according to claim 1, characterized in that: a unit type and a unit order are selected, including: for a laminate structure that mainly bears in-plane load and has a length-to-thickness ratio greater than a set value and does not need to analyze interlaminar stress, a two-dimensional unit is selected; when the laminate structure is subjected to a normal force that cannot be ignored, the transverse shear effect is greater than a set value, or the interlaminar stress or the stress of a local area is concerned, a three-dimensional unit is used; for a structure that needs to be concerned, a cohesive element is selected or viscous contact is used; for a sandwich structure, a three-dimensional unit is selected. If the out-of-plane stress is negligible, a two-dimensional unit is used; for fastener connection of a composite material, a one-dimensional unit is used for simulation. If the connection is critical, a three-dimensional unit is used; when the structure shape is irregular, the deformation and stress distribution are complex, a high-order unit is selected. The calculation accuracy of an area greater than a set value should be selected by a high-order unit; a low-order unit is selected when the accuracy requirement is less than a set value. Transition units or multi-point constraints should be used at the connection positions of different order units.

6. The virtual analysis method of the composite material structure of the rail transit vehicle according to claim 1, characterized in that: a mesh density is configured, at least including: a setting for mesh density control. The structure is refined when the structure changes by more than a set value, the curvature of the curved surface changes by more than a set value, the load changes by more than a set value, and the parts of different material connections are refined; triangular element transition or MPC transition is used for transition between coarse and fine meshes. The mesh density of the stress response concerned area is greater than that of the displacement response concerned area. The unit size in the main bearing direction is less than a set value. The unit perpendicular to the direction is enlarged in size when the quality requirement is met.

7. The virtual analysis method of the composite material structure of the rail transit vehicle according to claim 1, characterized in that: mesh division is performed, including: The main geometric contour lines are reserved during meshing, the mesh is consistent with the geometric contour or the difference is within the set range, and for solid element mesh, three or more layers are ensured in the thickness direction of the structure, or the number of layers is reduced under the condition of meeting the solution accuracy; For symmetric structures, the ply properties should be consistent with the actual structure, and when there are missing plies in the laminate, the mesh should be divided according to the missing ply lines to ensure that the unit normal of each component is consistent.

8. The virtual analysis method of the rail transit vehicle composite structure according to claim 1, wherein: The configuration attributes include: composite structure attributes including single-layer material attributes, single-layer ply thickness, single-layer ply angle, lay-up direction, and ply sequence; The configuration of single-layer material allowable value test matrix, sandwich structure test matrix, adhesive layer material parameter test matrix, mechanical connection extrusion strength test matrix, single-layer ply elastic material parameters, and mesh quality check standards.

9. The virtual analysis method of the rail transit vehicle composite structure according to claim 8, wherein: The single-layer material attributes use anisotropic linear elastic material to simulate the material attributes of the composite laminate, and the material attributes use single-layer material allowable values, including: 0° or warp direction and 90° or weft direction tensile elastic modulus and strength; 0° or warp direction and 90° or weft direction compression elastic modulus and strength; main Poisson's ratio; longitudinal and transverse shear elastic modulus and strength; 0° or warp direction and 90° or weft direction tensile, compression strength, and longitudinal and transverse shear strength take B reference value, the elastic modulus takes the average value of tensile and compression elastic properties, and the main Poisson's ratio takes the average value.

10. The virtual analysis method of the rail transit vehicle composite structure according to claim 9, wherein: The determination of single-layer material allowable values includes: Determining the B reference value and A reference value of strength under different environmental condition combinations; For tensile and compression strength material allowable values, the statistical processed strength B reference value is used, and in the scheme design and preliminary design stage, if the test subsample is less than the set value and the data dispersion is greater than the set value, the material allowable value takes 85% of the average value and the value greater than the set value in the B reference value; For longitudinal and transverse shear strength material allowable values, the statistical processed strength or 1.5 times the yield strength B reference value smaller than the set value is used; The limit shear strength B reference value is taken as the material allowable value; when the longitudinal and transverse shear strength is the key performance, 1.5 times the yield strength B reference value is taken as the material allowable value; For modulus material allowable values, the average value of all test data under each environmental condition is used.

11. The virtual analysis method of the rail transit vehicle composite structure according to claim 8, wherein: A ply reference coordinate system is defined, the ply angle of each single layer is defined in the ply reference coordinate system, and the nominal ply angle and the actual ply angle have a deviation of no more than a set angle; The lay-up stacking direction and sequence are defined, the lay-up stacking direction of the laminate is defined by the unit normal, the unit normal of the same laminate area should be consistent and the same as the actual lay-up stacking direction, and the ply sequence is defined to be consistent with the actual laminate; The shell grid is located in the middle surface of the laminate cross section to ensure that the ply property effect is consistent with the design.

12. The virtual analysis method of a rail transit vehicle composite structure according to claim 8, characterized in that: The failure criterion is configured, including: The strength checking of the composite structure includes the strength checking based on the single-layer strength failure theory of the composite material, and the strength value adopted by the single-layer strength failure theory of the composite material adopts the material allowable value; According to the requirements, the failure criterion and the stress and strain output are set, at least including the stress and strain of the dangerous layer and the stress and strain value of the whole laminate.

13. The virtual analysis method of a rail transit vehicle composite structure according to claim 8, characterized in that: The boundary conditions are applied, including: The virtual model constraints are applied according to the actual installation conditions, the constraint area should accurately reflect the actual constraint condition, the load type is selected according to the standard or actual test load, and the load size, direction and action area are consistent with the actual load condition; The mass load should be applied in the form of concentrated load, the mass of the non-bearing structure is loaded in the form of uniform distribution, and the unprepared mass and the center of gravity position of the vehicle body structure are consistent with the design.

14. The virtual analysis method of a rail transit vehicle composite structure according to claim 1, characterized in that: After the load boundary conditions are applied, the virtual model is checked, and the grid elements are checked to meet the set value or set range requirements.

15. The virtual analysis method of a rail transit vehicle composite structure according to claim 1, characterized in that: The results are evaluated, and when the static strength of the composite structure is verified, it is ensured that the structure does not produce harmful deformation and damage under the limit load; under the condition of the limit load and the most severe environment combination, the structure does not occur overall damage; For the strength evaluation of the limit load, the first layer failure criterion and the limit strain method are adopted, the failure of the composite structure includes the failure of the laminate and the interlayer structure, the mechanical connection failure and the adhesive failure; the failure criterion of the laminate is divided into the failure criterion based on the single-layer strength and the limit strain failure based on the laminate; The evaluation includes the verification and evaluation of the finite element model and the failure criterion, and the static strength evaluation verification, wherein: The verification and evaluation of the finite element model and the failure criterion are to check the convergence of the model calculation results, analyze the rationality of the stress concentration position, verify the finite element model and the failure criterion according to the block-by-block analysis process, and compare the finite element analysis results with the test results to adjust the finite element analysis model and recalculate and evaluate based on the test results; The static strength evaluation verification is to perform the static strength evaluation verification of the whole vehicle level by using the verified finite element model and the failure criterion, and when the static strength result meets the corresponding failure criterion and the design value, the static strength of the structure meets the strength requirement, and the static strength test is performed according to the finite element analysis result.

16. A virtual analysis system of a rail transit vehicle composite structure, characterized in that: including: The requirement configuration module is configured to configure the requirements of the virtual analysis of the rail transit equipment composite structure, including: configuring the basic requirements, the unit system and the coordinate system; The model construction module is configured to establish a virtual analysis model according to the composite material structure parameters of the rail transit vehicle, including: constructing a geometric topology model, selecting a unit type and a unit order, configuring a grid density, performing grid division, configuring attributes, configuring failure criteria, and applying load boundary conditions; The virtual analysis module is configured to perform virtual testing of the rail transit composite material structure according to the virtual analysis model and generate virtual testing results, including: Determining material allowable values, and performing initial bearing capacity analysis using the material allowable values; According to the bearing capacity analysis of the structure in the initial stage, selecting a key area for subsequent testing verification; Determining the most critical strength failure mode of each design feature; Selecting a test environment that can produce a strength criticality failure mode; Testing multiple element-level test samples, each sample simulating a selected failure mode and loading condition, and comparing with analysis prediction; Increasing the test complexity to evaluate more complex loading conditions and the failure probability of several potential damage modes; comparing the test results with the analysis prediction, and adjusting the analysis model or design value as needed; Determining and performing full-size component static testing as needed to verify internal loads and structural integrity, and comparing with analysis; Performing whole-vehicle-level static finite element analysis, using the determined design value to perform structure limit strength checking, and performing strength evaluation of damage coefficient and safety margin; The output results include all or part of the stress, strain and deformation contour maps of the concerned parts; The single-layer results of the laminate should be identified globally to enable tracking of the results by layer; According to the laminate failure mode, output the corresponding stress and strain values, including at least the stress and strain of the dangerous layer and the overall stress and strain of the laminate; When the normal force on the laminate structure is not negligible, the transverse shear effect is greater than a set value, or the interlaminar stress or local area stress is concerned, the interlaminar stress value is generated.

17. A computer-readable storage medium having stored thereon a program, the program comprising instructions which, when executed by a computer, cause the computer to perform the method of any one of claims 1 to 16. The program is executed by the processor to realize the steps in the virtual analysis method of the rail transit vehicle composite material structure according to any one of claims 1-15.

18. An electronic device comprising a memory, a processor, and a program stored on the memory and executable on the processor, the program comprising instructions for: The processor executes the program to realize the steps in the virtual analysis method of the rail transit vehicle composite material structure according to any one of claims 1-15.

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