Carbon fiber auxiliary frame service safety simulation evaluation method based on Tsai-Wu criterion

Abstract

A carbon fiber auxiliary frame service safety simulation evaluation method based on a Tsai-Wu criterion relates to the technical field of safety simulation evaluation, and comprises the following steps: characterizing a carbon fiber and metal material parameter matrix, establishing a carbon fiber and metal material model, and carrying out carbon fiber auxiliary frame overall modeling geometric cleaning and carbon fiber body partitioning. The method comprises the steps of establishing a carbon fiber auxiliary frame unit model comprising carbon fibers, metal embedded parts, steel bolts and foam, establishing a different material contact relation and a bonding and screw joint connection relation, setting service loads and boundary conditions, and performing service safety simulation evaluation; according to the method, the anisotropic property of the carbon fiber material is fully considered, a refined modeling method closer to a real connection relation is adopted for complex connection modes of glue joint and screw joint in similar products, in addition, multiple judgment methods are introduced in the evaluation process, and the evaluation accuracy is improved. Therefore, the service safety of the carbon fiber auxiliary frame in the complex stress state can be evaluated more comprehensively and accurately.

Description

Technical Field

[0001] The invention relates to the technical field of safety simulation evaluation, and in particular to a service safety simulation evaluation method for a carbon fiber subframe based on the Tsai-Wu criterion. Background Art

[0002] With the continuous development of the automobile industry, lightweight design has become an important direction to improve vehicle performance. Carbon fiber materials are increasingly used in automobile manufacturing due to their high strength and low density. As a key component connecting the body and the suspension system, the safety of the subframe is directly related to the driving stability of the vehicle and the safety of passengers.

[0003] Safety simulation evaluation of carbon fiber subframes is an important means to verify their design reliability. The simulation evaluation results can provide an important basis for design optimization and ensure the safety and reliability of carbon fiber subframes in actual use.

[0004] However, the existing simulation evaluation method for the service safety of carbon fiber subframes is mainly based on the assumption of material isotropy in terms of modeling, and uses rigid units to simplify complex connection methods such as bolted connections commonly found in subframes. In terms of result evaluation, it often relies on only a single evaluation indicator such as stress or strain. This method not only cannot fully reflect the actual service performance of the subframe under complex stress conditions, but also greatly reduces the credibility of the evaluation results.

[0005] Therefore, it is particularly urgent to propose a safety simulation assessment method that can more comprehensively and accurately evaluate the service safety of the subframe under complex stress states while fully considering the anisotropic properties of the material. Summary of the invention

[0006] In order to solve the above technical problems, the present invention proposes a carbon fiber subframe service safety simulation evaluation method based on the Tsai-Wu criterion, comprising the following steps: S1, parameter matrix characterization of carbon fiber and metal materials; S2, establish material models of carbon fiber and metal; S3, clean up the overall geometry of the carbon fiber subframe and partition the carbon fiber body; S4, establishing a carbon fiber subframe unit model including carbon fiber, metal embedded parts, steel bolts and foam; S5, establishing the contact relationship between different materials, adhesive connection and screw connection relationship; S6, setting service loads and boundary conditions; S7, conduct service safety simulation assessment; When the service safety simulation evaluation results meet the design requirements, the simulation evaluation is terminated; when the service safety simulation evaluation results do not meet the design requirements, the overall shape optimization of the carbon fiber subframe is prioritized and steps S4-S7 are repeated, and then when the service safety simulation evaluation results meet the design requirements, the simulation evaluation is terminated; and if the service safety simulation evaluation results still do not meet the design requirements, the carbon fiber ply adjustment is performed and steps S2-S7 are repeated until the service safety simulation evaluation results meet the design requirements.

[0007] Furthermore, step S1 is specifically as follows: S101, obtaining the density, longitudinal tensile elastic modulus, transverse tensile elastic modulus, in-plane shear modulus, principal Poisson's ratio, longitudinal tensile strength, longitudinal compressive strength and interlaminar shear strength of the carbon fiber material through tensile and compression tests on carbon fiber material sample bars or samples, and detecting the accuracy of the carbon fiber material test data based on the restriction relationship between the elastic constants of orthogonal anisotropic materials; S102, obtaining the density, longitudinal tensile elastic modulus, principal Poisson's ratio and stress-strain relationship curve of the metal material through a tensile test of a metal material sample rod or sample piece, completing the comparison between the tensile simulation of the sample rod or sample piece and the test, and determining the stress-strain relationship curve for simulation.

[0008] Furthermore, step S2 is specifically as follows: S201, establishing a carbon fiber material model according to the carbon fiber material test data obtained in S101, wherein the general description of the carbon fiber material model is expressed as:

[0009] In the formula, is the stress matrix, is the symmetric stiffness matrix, For strain, strain due to thermal expansion; S202, establishing a metal material model according to the simulation stress-strain relationship curve determined in S102.

[0010] Furthermore, according to the carbon fiber material model established in step S201 and the product layup information obtained from the product design end or the process design end, the consistency of the simulated layup with the design or process layup information is achieved through the Abaqus section management tool.

[0011] Furthermore, step S3 is specifically as follows: S301, custom geometry cleaning rules, including definition of minimum size (Min Size), maximum size (MaxSize), aspect ratio (Aspect Ratio), warpage (Warpage), maximum interior angle (Max Interior Angle), minimum interior angle (Min Interior Angle), skew (Skew) and Jacobian (Jacobian), and the overall shape of the carbon fiber subframe is geometrically cleaned according to the defined geometry cleaning rules; S302, determining the main direction of the ply according to the ply information obtained from the product design end or the process design end, and partitioning the carbon fiber body and defining the local coordinate system according to the main direction of the ply.

[0012] Further, step S302 is specifically as follows: S3021, the fibers in the carbon fiber single-layer plate are neatly arranged in a single direction, the fiber direction is the longitudinal direction, the direction perpendicular to the fiber direction is the transverse direction, and the remaining direction is the thickness direction, which are represented by a, b, and c respectively, becoming the main axis of the material; S3022, forming a carbon fiber body by laying up the carbon fiber single-layer plate in S3021 according to a specified fiber direction and order; S3023, determining the main direction of the ply as the a principal axis; S3024, dividing the carbon fiber body into four areas: front beam, rear beam, left beam, and right beam, wherein the front beam and rear beam are one group, and the left beam and right beam are one group, for a total of two groups; S3025, define a separate local coordinate system for each group of two regions in S3024 to describe the fiber direction and order.

[0013] Furthermore, step S4 is specifically as follows: S401, delete and optimize the unnecessary features in the overall shape of the carbon fiber subframe, and refine the local units for the contact surfaces that need to establish the contact relationship between different materials and the features that are prone to stress concentration; S402, for the carbon fiber body, select the traditional shell element S4R for unit division; for the metal embedded parts, select the second-order tetrahedron element C3D10 for unit division; for the steel bolt parts, select the second-order hexahedron element C3D8 for unit division; S403, assigning the material model established in step S2 to the carbon fiber body and the aluminum alloy metal part respectively, and selecting general steel material parameters for the material model of the steel bolt part; S404, assembling the carbon fiber body, metal embedded parts, steel bolt parts, and foam divided into units in S402 to establish a carbon fiber subframe unit model.

[0014] Furthermore, step S5 is specifically as follows: S501, establishing a contact relationship between different materials: establishing Tie contacts between the steel bolt and the carbon fiber body and the metal embedded parts, respectively, and establishing a general contact relationship between the carbon fiber body and the metal embedded parts; S502, establishing an adhesive connection relationship: establishing a shell unit connection between the carbon fiber body and the metal embedded part, and assigning the shell unit structural adhesive material properties; S503, establishing a screw connection relationship: defining a preload force of a steel bolt component, the preload force being consistent with an initial value of the steel bolt component during actual service.

[0015] Furthermore, step S6 is specifically as follows: S601, establishing hard points to which service loads and boundary conditions need to be applied, and establishing rigid units between the hard points and the carbon fiber subframe unit model to describe the connection relationship between the peripheral parts and the carbon fiber subframe unit model, excluding the screw connection parts; S602, according to the load information of each hard point position collected when the carbon fiber subframe is in actual service state of the vehicle, load is applied to the corresponding position in the carbon fiber subframe unit model, and boundary conditions are equivalently set according to the actual installation state of the carbon fiber subframe.

[0016] Further, step S7 is specifically as follows: S701, the service safety of carbon fiber body is evaluated by Tsai-Wu criterion, which is expressed as follows:

[0017] In the formula, is the failure function, is the strength parameter obtained by uniaxial tension or shear test, is the strength parameter obtained through equibiaxial test; when When it is less than 1, it means that the service safety simulation evaluation results meet the design requirements, otherwise it does not meet the requirements; S702, according to the working conditions experienced by the carbon fiber subframe in actual service, the yield strength or tensile strength is used for evaluation. If the equivalent stress borne by the metal embedded parts is less than the yield strength or tensile strength, it means that the service safety simulation evaluation results meet the design requirements, otherwise they do not meet the requirements.

[0018] Further, in step S702, the working conditions experienced by the carbon fiber subframe in actual service state include general working conditions and misuse conditions; when the working condition experienced is the general working condition, the yield strength is used for evaluation; when the working condition experienced is the misuse condition, the tensile strength is used for evaluation.

[0019] The beneficial effects of the present invention are as follows: the present invention fully considers the anisotropic properties of carbon fiber materials, and adopts a refined modeling method that is closer to the actual connection relationship for complex connection methods such as gluing and screwing in similar products. In addition, a variety of judgment methods are introduced in the evaluation process, so that the service safety of the carbon fiber subframe under complex stress states can be evaluated more comprehensively and accurately, providing a more scientific basis for the design and manufacture of the carbon fiber subframe. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The present invention is a flow chart of the carbon fiber subframe service safety simulation evaluation method.

[0021] Figure 2 The figure is a schematic diagram of a stress-strain relationship curve obtained by a tensile test of a metal material sample rod or sample piece in one embodiment of the present invention.

[0022] Figure 3 FIG. 1 is a schematic diagram of carbon fiber body partitions and local coordinate system definition according to an embodiment of the present invention.

[0023] Figure 4 This is a carbon fiber body unit model according to an embodiment of the present invention.

[0024] Figure 5 This is a metal embedded part unit model according to an embodiment of the present invention.

[0025] Figure 6 This is a steel bolt unit model according to an embodiment of the present invention.

[0026] Figure 7 This is a cloud diagram of the failure function simulation results of a carbon fiber body according to an embodiment of the present invention based on the Tsai-Wu criterion.

[0027] Figure 8 This is a cloud diagram of equivalent stress simulation results of aluminum alloy metal embedded parts according to an embodiment of the present invention. DETAILED DESCRIPTION

[0028] In order to more clearly understand the above-mentioned purpose, features and advantages of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0029] like Figure 1 A carbon fiber subframe service safety simulation evaluation method based on the Tsai-Wu criterion is shown, comprising the following steps: S1, parameter matrix characterization of carbon fiber and metal materials; S2, establish material models of carbon fiber and metal; S3, clean up the overall geometry of the carbon fiber subframe and partition the carbon fiber body; S4, establishing a carbon fiber subframe unit model including carbon fiber, metal embedded parts, steel bolts and foam; S5, establishing the contact relationship between different materials, adhesive connection and screw connection relationship; S6, setting service loads and boundary conditions; S7, conduct service safety simulation assessment; When the service safety simulation evaluation results meet the design requirements, the simulation evaluation is terminated; when the service safety simulation evaluation results do not meet the design requirements, the overall shape optimization of the carbon fiber subframe is prioritized and steps S4-S7 are repeated, and then when the service safety simulation evaluation results meet the design requirements, the simulation evaluation is terminated; and if the service safety simulation evaluation results still do not meet the design requirements, the carbon fiber ply adjustment is performed and steps S2-S7 are repeated until the service safety simulation evaluation results meet the design requirements.

[0030] In this embodiment, the metal embedded parts are aluminum alloy metal parts.

[0031] Step S1 is specifically as follows: S101, according to the requirements of GB / T 3354, GB / T3856 and other standards, through tensile and compression tests on carbon fiber material sample bars or samples, obtain the density, longitudinal tensile elastic modulus, transverse tensile elastic modulus, in-plane shear modulus, principal Poisson's ratio, longitudinal tensile strength, longitudinal compressive strength and interlaminar shear strength of the carbon fiber material, and according to the restriction relationship between the elastic constants of orthogonal anisotropic materials, detect the accuracy of the carbon fiber material test data, and after confirmation, it can be used as the input of the carbon fiber material model in step S2; S102, according to the requirements of GB / T 16865, obtain the density, longitudinal tensile elastic modulus, principal Poisson's ratio and stress-strain relationship curve of the metal material through tensile test of metal material sample bars or samples, and complete the benchmarking of sample bar or sample tensile simulation and test, and determine the stress-strain relationship curve for simulation, such as Figure 2 As shown, it can then be used as input for the metal material model in step S2.

[0032] Step S2 is specifically as follows: S201, assuming that the carbon fiber material is an orthogonal anisotropic, linear elastic material, a carbon fiber material model is established according to the carbon fiber material test data obtained in S101, so as to accurately establish a carbon fiber material model to describe different material behaviors. The general description of the carbon fiber material model is expressed as:

[0033] In the formula, is the stress matrix, is the symmetric stiffness matrix, For strain, strain due to thermal expansion; Based on the established carbon fiber material model and the product layup information obtained from the product design end or process design end, the Shell / Continuum Shell and Composit types in the Abaqus section management tool are used to achieve consistency between the simulated layup and the design or process layup information; S202, establishing a metal material model according to the simulation stress-strain relationship curve determined in S102.

[0034] Step S3 is specifically as follows: S301, customizing geometric cleaning rules, including defining the minimum size (Min Size), maximum size (MaxSize), aspect ratio (Aspect Ratio), warpage (Warpage), maximum interior angle (Max Interior Angle), minimum interior angle (Min Interior Angle), skew (Skew) and Jacobian (Jacobian), and performing geometric cleaning on the overall shape of the carbon fiber subframe according to the defined geometric cleaning rules to prepare for step S4; in this embodiment, the specific geometric cleaning rule parameters are set as shown in the following table:

[0035] S302, determining the main direction of the ply according to the ply information obtained from the product design end or the process design end, and partitioning the carbon fiber body and defining the local coordinate system according to the main direction of the ply.

[0036] Wherein, step S302 is specifically as follows: S3021, the fibers in the carbon fiber single-layer plate are neatly arranged in a single direction, the fiber direction is the longitudinal direction, the direction perpendicular to the fiber direction is the transverse direction, and the remaining direction is the thickness direction, which are represented by a, b, and c respectively, becoming the main axis of the material; S3022, forming a carbon fiber body by laying up the carbon fiber single-layer plate in S3021 according to a specified fiber direction and order; S3023, determining the main direction of the ply as the a principal axis; S3024, such as Figure 3 As shown, considering that the carbon fiber body is a frame structure, combined with the layup information obtained from the process design end, in order to ensure the consistency of the simulated layup information and the process layup information, the body needs to be partitioned. Here, the carbon fiber body is divided into four areas: front beam, rear beam, left beam, and right beam. The front beam and rear beam are one group, and the left beam and right beam are one group, for a total of two groups; S3025, define a separate local coordinate system for each group of two regions in S3024 to describe the fiber direction and order, where the local coordinate system X-axis is the main direction of the ply a, the Y-axis is b perpendicular to the fiber direction, and the Z-axis is the thickness direction c.

[0037] Step S4 is specifically as follows: S401, delete and optimize the unnecessary features (such as lines, surfaces, bosses, lettering, etc.) in the overall shape of the carbon fiber subframe, and perform local unit refinement on the contact surfaces that need to establish the contact relationship between different materials and the features that are prone to stress concentration; S402, such as Figure 4-Figure 6 As shown, for the carbon fiber body, the traditional shell element S4R is selected for unit division; for the metal embedded parts, the second-order tetrahedron element C3D10 is selected for unit division; for the steel bolt parts, the second-order hexahedron element C3D8 is selected for unit division; S403, assigning the material model established in step S2 to the carbon fiber body and the aluminum alloy metal part respectively, and selecting general steel material parameters for the material model of the steel bolt part; S404, assembling the carbon fiber body, metal embedded parts, steel bolt parts, and foam divided into units in S402 to establish a carbon fiber subframe unit model.

[0038] Step S5 is specifically as follows: S501, establish contact relationship between different materials: simulate the interaction between components of different materials, such as contact surface pressure, friction, sliding, etc., thereby establishing Tie contact between the steel bolt and the carbon fiber body and metal embedded parts, and establishing general contact relationship between the carbon fiber body and the metal embedded parts (Note: Tie contact binds the interaction part of the model together, and there is no relative motion between the two. General contact considers the normal and tangential motion of the interaction part at the same time); S502, establishing an adhesive connection relationship: establishing a shell unit connection between the carbon fiber body and the metal embedded part, and assigning the shell unit structural adhesive material properties; S503, establishing a screw connection relationship: defining a preload force of a steel bolt component, the preload force being consistent with an initial value of the steel bolt component during actual service.

[0039] Step S6 is specifically as follows: S601, establishing hard points to which service loads and boundary conditions need to be applied, and establishing rigid units between the hard points and the carbon fiber subframe unit model to describe the connection relationship between the peripheral parts and the carbon fiber subframe unit model, excluding the screw connection parts; S602, according to the load information (such as force, moment, etc.) of each hard point position collected when the carbon fiber subframe is in actual service state of the vehicle, loads are applied to corresponding positions in the carbon fiber subframe unit model, and boundary conditions are equivalently set according to the actual installation state of the carbon fiber subframe.

[0040] Step S7 is specifically as follows: S701, the service safety of carbon fiber body is evaluated by Tsai-Wu criterion, which is expressed as follows:

[0041] In the formula, is the failure function, is the strength parameter obtained by uniaxial tension or shear test, is the strength parameter obtained through equibiaxial test; when When it is less than 1, it means that the service safety simulation evaluation results meet the design requirements, otherwise it does not meet the requirements; like Figure 7 In this embodiment, The maximum value is 0.891, which means that the service safety simulation evaluation results meet the design requirements, that is, it is safe in service.

[0042] S702, based on the working conditions experienced by the carbon fiber subframe in actual service, including general working conditions and misuse conditions, when the working conditions experienced are general working conditions, the yield strength is used for evaluation, and when the working conditions experienced are misuse conditions, the tensile strength is used for evaluation; if the equivalent stress borne by the metal embedded parts is less than the yield strength or tensile strength, it means that the service safety simulation evaluation results meet the design requirements, otherwise they do not meet the requirements.

[0043] like Figure 8 As shown, in this example, the maximum equivalent stress of the aluminum alloy embedded parts under normal working conditions is 85.4MPa, which is much smaller than the aluminum alloy yield strength of 260MPa. The maximum equivalent stress under misuse conditions is 90.7MPa, which is much smaller than the aluminum alloy tensile strength of 310MPa. The service safety simulation evaluation results meet the design requirements, that is, they are safe in service.

[0044] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A carbon fiber subframe service safety simulation evaluation method based on Tsai-Wu criterion, characterized in that: The following steps are involved: S1, parameter matrix characterization of carbon fiber and metal materials; S2, establish material models of carbon fiber and metal; S3, clean up the overall geometry of the carbon fiber subframe and partition the carbon fiber body; S4, establishing a carbon fiber subframe unit model including carbon fiber, metal embedded parts, steel bolts and foam; S5, establishing the contact relationship between different materials, adhesive connection and screw connection relationship; S6, setting service loads and boundary conditions; S7, conduct service safety simulation assessment; When the service safety simulation evaluation results meet the design requirements, the simulation evaluation is terminated; When the service safety simulation evaluation results do not meet the design requirements, the overall shape optimization of the carbon fiber subframe is prioritized and steps S4-S7 are repeated. When the service safety simulation evaluation results meet the design requirements, the simulation evaluation is terminated. If the service safety simulation evaluation results still do not meet the design requirements, the carbon fiber layup is adjusted and steps S2-S7 are repeated until the service safety simulation evaluation results meet the design requirements.

2. The carbon fiber subframe service safety simulation evaluation method based on Tsai-Wu criterion as claimed in claim 1, characterized in that: Step S1 is specifically as follows: S101, obtaining the density, longitudinal tensile elastic modulus, transverse tensile elastic modulus, in-plane shear modulus, principal Poisson's ratio, longitudinal tensile strength, longitudinal compressive strength and interlaminar shear strength of the carbon fiber material through tensile and compression tests on carbon fiber material sample bars or samples, and detecting the accuracy of the carbon fiber material test data based on the restriction relationship between the elastic constants of orthogonal anisotropic materials; S102, obtaining the density, longitudinal tensile elastic modulus, principal Poisson's ratio and stress-strain relationship curve of the metal material through a tensile test of a metal material sample rod or sample piece, completing the comparison between the tensile simulation of the sample rod or sample piece and the test, and determining the stress-strain relationship curve for simulation.

3. A carbon fiber subframe service safety simulation evaluation method based on Tsai-Wu criterion as claimed in claim 2, characterized in that: Step S2 is specifically as follows: S201, establishing a carbon fiber material model according to the carbon fiber material test data obtained in S101, wherein the general description of the carbon fiber material model is expressed as: ； In the formula, is the stress matrix, is the symmetric stiffness matrix, For strain, strain due to thermal expansion; S202, establishing a metal material model according to the simulation stress-strain relationship curve determined in S102.

4. A carbon fiber subframe service safety simulation evaluation method based on Tsai-Wu criterion as claimed in claim 3, characterized in that: According to the carbon fiber material model established in step S201 and the product layup information obtained from the product design end or the process design end, the consistency of the simulated layup with the design or process layup information is achieved through the Abaqus section management tool.

5. The carbon fiber subframe service safety simulation evaluation method based on Tsai-Wu criterion as claimed in claim 4, characterized in that: Step S3 is specifically as follows: S301, custom geometry cleaning rules, including definition of minimum size, maximum size, aspect ratio, warpage, maximum inner angle, minimum inner angle, skewness and Jacobi, and geometric cleaning of the overall shape of the carbon fiber subframe according to the defined geometry cleaning rules; S302, determining the main direction of the ply according to the ply information obtained from the product design end or the process design end, and partitioning the carbon fiber body and defining the local coordinate system according to the main direction of the ply.

6. A carbon fiber subframe service safety simulation evaluation method based on Tsai-Wu criterion as claimed in claim 5, characterized in that: Step S302 is specifically as follows: S3021, the fibers in the carbon fiber single-layer plate are neatly arranged in a single direction, the fiber direction is the longitudinal direction, the direction perpendicular to the fiber direction is the transverse direction, and the remaining direction is the thickness direction, which are represented by a, b, and c respectively, becoming the main axis of the material; S3022, forming a carbon fiber body by laying up the carbon fiber single-layer plate in S3021 according to a specified fiber direction and order; S3023, determining the main direction of the ply as the a principal axis; S3024, dividing the carbon fiber body into four areas: front beam, rear beam, left beam, and right beam, wherein the front beam and rear beam are one group, and the left beam and right beam are one group, for a total of two groups; S3025, define a separate local coordinate system for each group of two regions in S3024 to describe the fiber direction and order.

7. The carbon fiber subframe service safety simulation evaluation method based on Tsai-Wu criterion as claimed in claim 6, characterized in that: Step S4 is specifically as follows: S401, delete and optimize the unnecessary features in the overall shape of the carbon fiber subframe, and refine the local units for the contact surfaces that need to establish the contact relationship between different materials and the features that are prone to stress concentration; S402, for the carbon fiber body, select the traditional shell element S4R for unit division; for the metal embedded parts, select the second-order tetrahedron element C3D10 for unit division; for the steel bolt parts, select the second-order hexahedron element C3D8 for unit division; S403, assigning the material model established in step S2 to the carbon fiber body and the aluminum alloy metal part respectively, and selecting general steel material parameters for the material model of the steel bolt part; S404, assembling the carbon fiber body, metal embedded parts, steel bolt parts, and foam divided into units in S402 to establish a carbon fiber subframe unit model.

8. The carbon fiber subframe service safety simulation evaluation method based on Tsai-Wu criterion as claimed in claim 7, characterized in that: Step S5 is specifically as follows: S501, establishing a contact relationship between different materials: establishing Tie contacts between the steel bolt and the carbon fiber body and the metal embedded parts, respectively, and establishing a general contact relationship between the carbon fiber body and the metal embedded parts; S502, establishing an adhesive connection relationship: establishing a shell unit connection between the carbon fiber body and the metal embedded part, and assigning the shell unit structural adhesive material properties; S503, establishing a screw connection relationship: defining a preload force of a steel bolt component, the preload force being consistent with an initial value of the steel bolt component during actual service.

9. A carbon fiber subframe service safety simulation evaluation method based on Tsai-Wu criterion as claimed in claim 8, characterized in that: Step S6 is specifically as follows: S601, establishing hard points to which service loads and boundary conditions need to be applied, and establishing rigid units between the hard points and the carbon fiber subframe unit model to describe the connection relationship between the peripheral parts and the carbon fiber subframe unit model, excluding the screw connection parts; S602, according to the load information of each hard point position collected when the carbon fiber subframe is in actual service state of the vehicle, load is applied to the corresponding position in the carbon fiber subframe unit model, and boundary conditions are equivalently set according to the actual installation state of the carbon fiber subframe.

10. A carbon fiber subframe service safety simulation evaluation method based on Tsai-Wu criterion as claimed in claim 9, characterized in that: Step S7 is specifically as follows: S701, the service safety of carbon fiber body is evaluated by Tsai-Wu criterion, which is expressed as follows: ； In the formula, is the failure function, is the strength parameter obtained by uniaxial tension or shear test, is the strength parameter obtained through equibiaxial test; when When it is less than 1, it means that the service safety simulation evaluation results meet the design requirements, otherwise it does not meet the requirements; S702, according to the working conditions experienced by the carbon fiber subframe in actual service state, the yield strength or tensile strength is used for evaluation. If the equivalent stress borne by the metal embedded parts is less than the yield strength or tensile strength, it means that the service safety simulation evaluation result meets the design requirements, otherwise it does not meet the requirements. In step S702, the working conditions experienced by the carbon fiber subframe in actual service state include general working conditions and misuse conditions. When the working condition experienced is the general working condition, the yield strength is used for evaluation; when the working condition experienced is the misuse condition, the tensile strength is used for evaluation.

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