A crash simulation method for steel-aluminum hybrid body sheet metal adhesive bonding connection

Abstract

This invention relates to a collision simulation method for adhesive joints in steel-aluminum hybrid vehicle body panels, including: structural adhesive body mechanical property testing; shear failure testing of structural adhesive using thick lap shear specimens to obtain the maximum shear stress, critical shear energy release rate, and parallel segment ratio under shear conditions; tensile failure testing of structural adhesive using thick butt joint specimens to obtain the maximum normal stress and critical tensile energy release rate; calibration of structural adhesive body mechanical properties to establish a structural adhesive material card; establishment of a structural adhesive body mechanical property calibration model; preparation of lap and T-peel test specimens for adhesive joints using corresponding connected metal sheets; sample-level calibration of adhesive joint mechanical properties; and component-level calibration. This invention considers the influence of different materials and thicknesses of the connected parts and different coating baking temperatures on the mechanical properties of the adhesive joints, and can accurately simulate the deformation and failure behavior of adhesive joints in steel-aluminum hybrid vehicle body panels under collision conditions.

Description

Technical Field

[0001] This invention belongs to the field of automotive adhesive joint simulation technology, specifically relating to a collision simulation method for adhesive joints of steel-aluminum hybrid body sheet metal. Background Technology

[0002] With the continuous increase in the number of cars in my country, the traffic accident rate is showing an upward trend, and the government and consumers are paying more and more attention to the safety performance of cars. On the other hand, in recent years, with increasingly stringent regulations on vehicle emissions and fuel consumption, lightweight vehicle technology has become increasingly important. The application of high-strength steel and aluminum alloys in vehicle bodies is gradually increasing, and the strength of structural components is gradually increasing, leading to a higher possibility of failure of connection joints between structural components.

[0003] In traditional automotive crash simulations, joints between structural components typically employ rigid connections that are unlikely to fail. However, with increasing automotive lightweighting and the widespread use of aluminum alloys, the types of joints between structural components are gradually increasing, leading to more joint failures. Accurately simulating joint failure behavior has become a prerequisite for accurate crash simulation models. Adhesive bonding, as an ideal method for joining dissimilar materials, can achieve connections between steel, aluminum, plastics, and composite materials, making it highly suitable for sheet metal connections in steel-aluminum hybrid vehicle bodies.

[0004] Existing automotive adhesive joint simulations do not consider the influence of the material properties of the connected components on the mechanical properties of the joint; they simply model the adhesive as a separate component, assigning it uniform material property parameters. In actual use, the material and thickness of the connected components both affect the mechanical properties of the adhesive joint. Due to the difference in the coefficients of linear expansion between the structural adhesive and the connected steel and aluminum sheet metal, residual stress is introduced into the adhesive layer during adhesive curing and vehicle body painting baking, causing varying degrees of reduction in the load-bearing capacity of the joint. With the widespread adoption of adhesive bonding technology, developing a highly accurate joint simulation method is particularly important. Summary of the Invention

[0005] The purpose of this invention is to provide a collision simulation method for automotive steel-aluminum hybrid body sheet metal adhesive joints with high computational stability and high accuracy, so as to solve the problem of low accuracy in existing collision simulation methods for automotive steel-aluminum hybrid body sheet metal adhesive joints.

[0006] The objective of this invention is achieved through the following technical solution:

[0007] A collision simulation method for adhesive bonding of steel-aluminum hybrid vehicle body sheet metal includes the following steps:

[0008] A. Mechanical property tests of structural adhesive:

[0009] A1. Prepare tensile test specimens of the structural adhesive body to obtain the basic mechanical property parameters of the structural adhesive after curing, such as elastic modulus and Poisson's ratio.

[0010] A2. Shear failure tests of structural adhesive were conducted using thick lap shear specimens to obtain the maximum shear stress, critical shear energy release rate, and the proportion of parallel segments under shear conditions of the structural adhesive.

[0011] A3. Tensile failure test of structural adhesive was conducted using thick butt joint specimens to obtain the maximum normal stress and tensile critical energy release rate of structural adhesive.

[0012] B. Calibration of structural adhesive bulk mechanical properties test:

[0013] B1. Using keywords and combining the structural adhesive's bulk mechanical properties obtained in step A, establish a material card for the structural adhesive.

[0014] B2. Based on the shear and tensile fracture failure tests in step A, establish a calibration model for the structural adhesive's bulk mechanical properties. The thick-walled component with auxiliary loading and the structural adhesive are both modeled using solid elements, and they are connected by common nodes. Adjust the key parameters of the material card until the COR fit between the simulation and experimental force-displacement curves reaches more than 90%.

[0015] C. Mechanical property testing of sample-grade adhesive joints:

[0016] Based on the actual application of the vehicle, the corresponding metal plates to be connected were selected to make adhesive joint lap joint and T-type peel test specimens. The specimens were heat-treated under the same curing and baking temperature conditions as the actual vehicle.

[0017] D. Calibration of mechanical properties of sample-grade adhesive joints:

[0018] A simulation model for the mechanical properties of the sample-level adhesive joint was established. The metal base material was modeled using shell elements. Failure parameters such as the maximum normal stress, maximum shear stress, critical energy release rate, and the proportion of parallel segments under shear conditions of the structural adhesive material were corrected until the COR fit between the simulation and the test force-displacement curves reached more than 85%.

[0019] E. Component-level test calibration:

[0020] Conduct component-level impact tests. Based on the joint model calibrated in step D, establish a component impact test simulation model. Adjust the relevant parameters in the structural adhesive material card keywords until the COR fit of the simulation and test force-displacement curves reaches more than 85%. Combine the simulation and test joint failure modes to confirm the final adhesive joint simulation model.

[0021] Further, in step A1, a tensile test specimen of the structural adhesive body is prepared by simply curing the structural adhesive. The basic mechanical property parameters such as the elastic modulus and Poisson's ratio of the cured structural adhesive are obtained by using a multi-functional tensile testing machine.

[0022] Further, in step A1, the elastic modulus is calculated using the following formula:

[0023] E=(ΔF / S_0) / (ΔL / L_el)

[0024] ΔF is the change in tensile load between any two points A and B on the straight line segment of the load curve, ΔL is the change in axial displacement between two points A and B, S_0 is the cross-sectional area of ​​the tensile specimen, and L_el is the length of the axial gauge length in the tensile test.

[0025] The Poisson's ratio is obtained using the following formula:

[0026] μ=(Δt / L_et) / (ΔL / L_el)

[0027] Δt is the lateral deformation, and L_et is the length of the lateral gauge length.

[0028] Further, in step A2, the stress corresponding to the maximum strain value of the strain-displacement curve obtained from the experiment is the maximum shear stress of the structural adhesive, the area enclosed by the curve is the critical shear energy release rate, and the ratio of the displacement of the parallel segment to the total failure displacement is the proportion of the parallel segment under shear conditions.

[0029] Further, in step A3, the stress corresponding to the maximum strain value of the strain-displacement curve obtained from the experiment is the maximum normal stress of the structural adhesive, and the area enclosed by the curve is the tensile critical energy release rate.

[0030] Further, in step B1, the key parameters of the material card include elastic modulus, Poisson's ratio, maximum shear stress, critical shear energy release rate, parallel segment ratio under shear conditions, maximum normal stress, and critical tensile energy release rate.

[0031] Furthermore, in step C, when selecting the corresponding metal plates to be connected, the material grade and thickness must be consistent.

[0032] Further, in step C, force-displacement curves of joint lap shear and peel failure are obtained using a multi-functional tensile testing machine.

[0033] Further, in step D, the adhesive layer is modeled using solid elements, and a *CONTACT_TIED_NODES_TO_SURFACE contact is established between the adhesive layer and the base material.

[0034] Further, in step E, the test is designed based on the force characteristics of the component under collision conditions. A drop hammer impact test is adopted, with one end of the component with the adhesive joint fixed and the drop hammer impacting the other end of the component at a certain speed to obtain the force-displacement curve of the test.

[0035] Compared with the prior art, the beneficial effects of the present invention are:

[0036] Existing automotive adhesive joint simulation technologies do not consider the influence of the material properties of the connected components on the mechanical properties of the adhesive joint. They simply model the adhesive as a separate component and only consider the influence of the structural adhesive grade. Adhesive joints formed with the same grade of structural adhesive are assumed to have consistent mechanical properties. In actual use, the material and thickness of the connected components, as well as different coating and baking temperatures, all affect the mechanical properties of the adhesive joint. Even adhesive joints formed with the same grade of adhesive can have significantly different mechanical properties. This invention considers the influence of different materials and thicknesses of the connected components, as well as different coating and baking temperatures, on the mechanical properties of the adhesive joint. Compared with existing technologies, it is closer to actual working conditions and can accurately simulate the deformation and failure behavior of automotive steel-aluminum hybrid body sheet metal adhesive joints in collision conditions. Attached Figure Description

[0037] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0038] Figure 1 This is the overall process architecture of the present invention;

[0039] Figure 2 is a schematic diagram of the test specimen for the mechanical properties of the structural adhesive. Figure 2a This is a schematic diagram of the structural adhesive body tensile test specimen. Figure 2b This is a schematic diagram of the structural adhesive shear failure test specimen. Figure 2c Schematic diagram of the structural adhesive tensile failure test specimen;

[0040] Figure 3 is a schematic diagram of the test results of the structural adhesive's bulk mechanical properties, in which... Figure 3a This is a schematic diagram of the tensile test results of the structural adhesive. Figure 3b This is a schematic diagram of the shear failure test results for structural adhesive. Figure 3c Schematic diagram of tensile failure test results for structural adhesive;

[0041] Figure 4 shows a schematic diagram of the calibration results of the structural adhesive's bulk mechanical properties. Figure 4a Schematic diagram of structural adhesive shear failure calibration results; Figure 4bSchematic diagram of tensile failure calibration results for structural adhesive;

[0042] Figure 5 is a schematic diagram of the test specimen for the mechanical properties of the adhesive-bonded joint. Figure 5a This is a schematic diagram of a lap joint sample. Figure 5b This is a schematic diagram of a T-shaped peeling sample;

[0043] Figure 6 is a schematic diagram of the mechanical property calibration results of the sample-level adhesive joint, in which... Figure 6a This is a schematic diagram of the calibration result curve for the lap joint. Figure 6b This is a schematic diagram of the calibration results curve for the T-type peel test sample;

[0044] Figure 7 This is a schematic diagram of a drop hammer impact test for a component.

[0045] Figure 8 Schematic diagram of component drop hammer impact test calibration results.

[0046] In the figure, 1. is the thick-walled component for auxiliary loading; 2. is the adhesive layer; 3. is the base material; 4. is the loading direction for the impact test; 5. is the component with an adhesive joint; 6. is the impact fixing device; 7. is the impact hammer. Detailed Implementation

[0047] The present invention will be further described below with reference to embodiments:

[0048] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0049] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, in the description of this invention, terms such as "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0050] This invention provides a collision simulation method for adhesive joints in steel-aluminum hybrid body panels. Specifically, it utilizes the MAT*_169 material card in LS-DYNA software, combined with the relevant mechanical property parameters of the structural adhesive and the adhesive joint, to accurately simulate the deformation and failure behavior of the adhesive joint under automotive collision conditions through keyword parameter optimization. Due to the difference in the coefficient of linear expansion between the structural adhesive and the connected steel-aluminum sheet metal, residual stress is introduced into the adhesive layer during adhesive curing and body painting baking, resulting in a decrease in the load-bearing capacity of the adhesive joint.

[0051] The present invention provides a collision simulation method for adhesive bonding of steel-aluminum hybrid vehicle body sheet metal, comprising the following steps:

[0052] Step 1: Mechanical property testing of the structural adhesive:

[0053] Tensile test specimens of the structural adhesive were prepared by curing the structural adhesive itself. Basic mechanical properties such as the elastic modulus and Poisson's ratio after curing were obtained using a multi-functional tensile testing machine. The load-displacement curves obtained from the tensile tests are shown below. Figure 3a As shown, the elastic modulus is calculated using the following formula:

[0054] E=(ΔF / S_0) / (ΔL / L_el)

[0055] ΔF is the change in tensile load between any two points A and B on the straight segment of the load curve; ΔL is the change in axial displacement between points A and B; S_0 is the cross-sectional area of ​​the tensile specimen; and L_el is the axial gauge length of the tensile test. Poisson's ratio is obtained using the following formula:

[0056] μ=(Δt / L_et) / (ΔL / L_el)

[0057] Δt is the lateral deformation, and L_et is the length of the lateral gauge length.

[0058] To obtain the fracture parameters of the structural adhesive under shear conditions, shear failure tests were conducted using thick-lapped shear specimens. The maximum shear stress, critical shear energy release rate, and the proportion of parallel segments under shear conditions were obtained. The strain-displacement curves obtained from the tests are shown below. Figure 3b As shown, the "stress" corresponding to the maximum value of the curve strain is the maximum shear stress of the structural adhesive, the area enclosed by the curve is the critical shear energy release rate, and the ratio of the displacement of the parallel segment to the total failure displacement is the proportion of the parallel segment under shear conditions.

[0059] To obtain the fracture parameters of the structural adhesive under tensile conditions, tensile failure tests were conducted on thick butt-joint specimens to determine the maximum normal stress and tensile critical energy release rate of the structural adhesive. The strain-displacement curves obtained from the tests are shown below. Figure 3c As shown, the "stress" corresponding to the maximum value of the curve strain is the maximum normal stress of the structural adhesive, and the area enclosed by the curve is the tensile critical energy release rate.

[0060] The second step is to calibrate the mechanical properties of the structural adhesive:

[0061] Using the LS-DYNA software MAT*_169 keywords and combining the structural adhesive's bulk mechanical property parameters obtained in Step 1, an LS-DYNA material card for the structural adhesive was established. The material card's keyword parameters include elastic modulus, Poisson's ratio, maximum shear stress, shear critical energy release rate, parallel segment ratio under shear conditions, maximum normal stress, and tensile critical energy release rate. Based on the shear and tensile fracture failure tests from Step 1, a calibration model for the structural adhesive's bulk mechanical properties was established. Both the thick-walled component under auxiliary loading and the structural adhesive were modeled using solid elements, connected by shared nodes. The material card's keyword parameters were adjusted until the COR fit between the simulation and experimental force-displacement curves reached over 90%.

[0062] The third step is to conduct mechanical property testing on sample-level adhesive joints:

[0063] Based on the actual application of the vehicle, corresponding metal sheets to be connected (material grade and thickness must be consistent) were selected to prepare lap joint and T-peel test specimens for adhesive joints. The specimens were heat-treated under the same curing and baking temperatures as the actual vehicle. The force-displacement curves of lap joint shear and peel failure were obtained using a multi-functional tensile testing machine.

[0064] Step 4: Calibrating the mechanical properties of sample-level adhesive joints:

[0065] A simulation model for the mechanical properties of the adhesive joint at the sample level was established. The metal base material was modeled using shell elements, and the adhesive layer was modeled using solid elements. A contact was established between the adhesive layer and the base material using *CONTACT_TIED_NODES_TO_SURFACE. Failure parameters such as the maximum normal stress, maximum shear stress, critical energy release rate, and the proportion of parallel segments under shear conditions of the structural adhesive material were corrected until the COR fit between the simulation and experimental force-displacement curves reached over 85%.

[0066] Step 5, component-level test calibration:

[0067] Conduct component-level impact tests, designed based on the stress characteristics of the component under collision conditions. Drop hammer impact tests can be used, such as... Figure 7 As shown, one end of a component with an adhesive joint is fixed, and a drop hammer impacts the other end of the component at a certain speed, obtaining the force-displacement curve of the test. Based on the joint model calibrated in step four, a simulation model of the component impact test is established. The relevant parameters in the structural adhesive material card keywords are adjusted until the COR fit between the simulation and test force-displacement curves reaches over 85%. Combining the simulation and test joint failure modes, the final adhesive joint simulation model is confirmed.

[0068] Example 1

[0069] This implementation case details the collision simulation method for adhesive joints in automotive steel-aluminum hybrid body panels, including the following steps:

[0070] (1) Conduct mechanical property tests on the structural adhesive itself, mainly including three types of tests:

[0071] Tensile test specimens of the structural adhesive body were prepared by simply curing the structural adhesive, such as... Figure 2a As shown, the mechanical properties of the structural adhesive after curing, such as the elastic modulus and Poisson's ratio, were obtained using a multi-functional tensile testing machine. The load-displacement curves obtained from the tensile tests are shown below. Figure 3a As shown, the elastic modulus is calculated using the following formula:

[0072] E=(ΔF / S_0) / (ΔL / L_el)

[0073] ΔF is the change in tensile load between any two points A and B on the straight segment of the load curve; ΔL is the change in axial displacement between points A and B; S_0 is the cross-sectional area of ​​the tensile specimen; and L_el is the axial gauge length of the tensile test. Poisson's ratio is obtained using the following formula:

[0074] μ=(Δt / L_et) / (ΔL / L_el)

[0075] Δt is the lateral deformation, and L_et is the length of the lateral gauge length.

[0076] Shear failure tests of structural adhesives were conducted using thick lap shear specimens. The test specimens are as follows: Figure 2b As shown, the maximum shear stress of the structural adhesive, the critical shear energy release rate, and the proportion of parallel segments under shear conditions were obtained. The strain-displacement curves obtained from the experiment are shown below. Figure 3b As shown, the "stress" corresponding to the maximum value of the curve strain is the maximum shear stress of the structural adhesive, the area enclosed by the curve is the critical shear energy release rate, and the ratio of the displacement of the parallel segment to the total failure displacement is the proportion of the parallel segment under shear conditions.

[0077] Tensile failure tests of structural adhesives were conducted using thick butt joint specimens. The test specimens are as follows: Figure 2c As shown, the maximum normal stress and tensile critical energy release rate of the structural adhesive were obtained. The strain-displacement curves obtained from the experiment are shown below. Figure 3c As shown, the "stress" corresponding to the maximum value of the curve strain is the maximum normal stress of the structural adhesive, and the area enclosed by the curve is the tensile critical energy release rate.

[0078] The structural adhesive shear and tensile failure test specimens here are as follows: Figure 2b , Figure 2c As shown, the connected parts are made of thick-walled metal to ensure that no plastic deformation occurs during the test; the failure characteristics of the adhesive layer are examined alone.

[0079] 2. Calibration of the structural adhesive's bulk mechanical properties: Using the LS-DYNA software MAT*_169 keywords, and combining the structural adhesive's bulk mechanical property parameters (elastic modulus, Poisson's ratio, maximum normal stress, maximum shear stress, critical energy release rate, and parallel segment ratio under shear conditions) obtained in step 1, an LS-DYNA material card for the structural adhesive was established. A calibration model for the structural adhesive's bulk mechanical properties was established based on the shear and tensile fracture parameter tests obtained in step 1. Both the thick-walled component under auxiliary loading and the structural adhesive were modeled using solid elements, connected by common nodes. The relevant parameters in the material card keywords (elastic modulus, Poisson's ratio, maximum normal stress, maximum shear stress, critical energy release rate, and parallel segment ratio under shear conditions) were adjusted until the COR fit of the simulation and experimental force-displacement curves reached over 90%, resulting in the calibrated LS-DYNA material card for the structural adhesive. The calibrated simulation and experimental force-displacement curves are shown in Figure 4.

[0080] 3. Mechanical property testing of sample-level adhesive joints: Based on the actual application of the vehicle, select the corresponding metal sheets to be joined (material grade and thickness must be consistent) and prepare lap joint and T-peel test specimens, as shown in Figure 5. The specimens are heat-treated under the same curing and baking temperatures as the actual vehicle. The force-displacement curves of lap shear and peel failure of the joint are obtained using a multi-functional tensile testing machine.

[0081] The adhesive joints here are the same as those used in actual vehicles, taking into account the material and thickness of the connected parts, as well as the influence of residual stress in the adhesive layer introduced by changes in the curing and baking temperature field.

[0082] 4. Establish a simulation model for the mechanical properties of the adhesive joint at the sample level. The metal base material is modeled using shell elements, and the adhesive layer is modeled using solid elements. A *CONTACT_TIED_NODES_TO_SURFACE contact is established between the adhesive layer and the base material. Adjust failure parameters such as the maximum normal stress, maximum shear stress, critical energy release rate, and the proportion of parallel segments under shear conditions of the structural adhesive material card until the COR fit between the simulation and experimental force-displacement curves reaches over 85%. The calibrated simulation and experimental force-displacement curves are shown in Figure 6.

[0083] 5. Conduct component-level impact tests. The tests are designed based on the stress characteristics of the component under collision conditions, and can employ drop hammer impact testing, such as... Figure 7 As shown, one end of a component with an adhesive joint is fixed, and a drop hammer impacts the other end of the component at a certain speed, obtaining the force-displacement curve of the test. Based on the joint model calibrated in step four, a simulation model of the component impact test is established. The relevant parameters in the structural adhesive material card keywords are adjusted until the COR fit between the simulation and test force-displacement curves reaches over 85%. The calibrated simulation and test force-displacement curves are shown below. Figure 8As shown. By combining simulation and experimental joint failure modes, the final simulation model of the adhesive joint was confirmed.

[0084] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A collision simulation method for adhesive bonding of steel-aluminum hybrid vehicle body sheet metal, characterized in that, Includes the following steps: A. Mechanical property tests of structural adhesive: A1. Prepare tensile test specimens of the structural adhesive body to obtain the basic mechanical property parameters such as elastic modulus and Poisson's ratio after curing. Alternatively, prepare tensile test specimens of the structural adhesive body using only the cured structural adhesive, and obtain the basic mechanical property parameters such as elastic modulus and Poisson's ratio after curing using a multi-functional tensile testing machine. The elastic modulus is calculated using the following formula: E=(ΔF / S_0) / / (ΔL / L_el) ΔF is the change in tensile load between any two points A and B on the straight line segment of the load curve, ΔL is the change in axial displacement between two points A and B, S_0 is the cross-sectional area of ​​the tensile specimen, and L_el is the length of the axial gauge length in the tensile test. The Poisson's ratio is obtained using the following formula: μ=(Δt / L_et) / (ΔL / L_el) Δt is the lateral deformation, and L_et is the length of the lateral gauge length. A2. Shear failure tests of structural adhesive were conducted using thick lap shear specimens to obtain the maximum shear stress, critical shear energy release rate, and the proportion of parallel segments under shear conditions of the structural adhesive. The stress corresponding to the maximum strain value of the strain-displacement curve obtained from the test is the maximum shear stress of the structural adhesive, the area enclosed by the curve is the critical shear energy release rate, and the ratio of the displacement of the parallel segments under shear conditions to the total failure displacement is the proportion of parallel segments under shear conditions. A3. Tensile failure test of structural adhesive was carried out using thick butt joint specimens to obtain the maximum normal stress and tensile critical energy release rate of structural adhesive; the stress corresponding to the maximum value of strain in the strain-displacement curve obtained from the test is the maximum normal stress of structural adhesive, and the area enclosed by the curve is the tensile critical energy release rate. B. Calibration of structural adhesive bulk mechanical properties test: B1. Using keywords and combining them with the structural adhesive's bulk mechanical property parameters obtained in step A, establish a material card for the structural adhesive. The key parameters of the material card include elastic modulus, Poisson's ratio, maximum shear stress, critical shear energy release rate, parallel segment ratio under shear conditions, maximum normal stress, and critical tensile energy release rate. B2. Based on the shear and tensile fracture failure tests in step A, establish a calibration model for the structural adhesive's bulk mechanical properties. The thick-walled component with auxiliary loading and the structural adhesive are both modeled using solid elements, and they are connected by common nodes. Adjust the key parameters of the material card until the COR fit between the simulation and experimental force-displacement curves reaches more than 90%. C. Mechanical property test of sample-level adhesive joints: When selecting the corresponding metal plates to be joined, the material grade and thickness should be consistent; the force-displacement curves of joint lap shear and peel failure are obtained by using a multi-functional tensile testing machine; Based on the actual application of the vehicle, the corresponding metal plates to be connected were selected to make adhesive joint lap joint and T-type peel test specimens. The specimens were heat-treated under the same curing and baking temperature conditions as the actual vehicle. D. Mechanical property test calibration of sample-level adhesive joints: The adhesive layer is modeled using solid elements, and a *CONTACT_TIED_NODES_TO_SURFACE contact is established between the adhesive layer and the base material; A simulation model for the mechanical properties of the sample-level adhesive joint was established. The metal base material was modeled using shell elements. Failure parameters such as the maximum normal stress, maximum shear stress, critical energy release rate, and the proportion of parallel segments under shear conditions of the structural adhesive material were corrected until the COR fit between the simulation and the test force-displacement curves reached more than 85%. E. Component-level test calibration: Conduct component-level impact tests. Based on the joint model calibrated in step D, establish a component impact test simulation model. Adjust relevant parameters in the structural adhesive material card keywords until the COR fit of the simulation and test force-displacement curves reaches more than 85%. Combine the joint failure modes of the simulation and test to confirm the final adhesive joint simulation model. The test is designed according to the stress characteristics of the component under collision conditions. A drop hammer impact test is adopted. One end of the component with the adhesive joint is fixed, and the drop hammer impacts the other end of the component at a certain speed to obtain the force-displacement curve of the test.

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