Automobile body structure robustness design method under automobile collision failure condition

Abstract

The invention discloses a vehicle body structure robustness design method under a vehicle collision failure condition, which comprises the following steps of: firstly, analyzing a collision video, and analyzing a front 25% small offset collision video frame by frame; then a failure position is selected, and it is assumed that the collision side of the front 25% small offset collision is located on the left side of vehicle advancing; an analysis matrix is defined; generating a whole vehicle collision CAE calculation model in batches; submitting calculation; and finally, the stability of the vehicle body structure design scheme is verified, the step S1 is not limited to analysis of the collision video of the designed vehicle, and the position point with failure in the collision process is selected in the step S2. According to the method, the cost is low (mechanical property testing of local failure positions is not needed), quick response can be achieved (a large amount of calculation case is designed to quickly obtain deformation verification results of key positions of the vehicle body), and meanwhile, the structure is reliable (the designed vehicle body structure can meet the front 25% small offset collision requirement under any collision failure combination condition).

Description

Technical Field

[0001] The invention relates to the technical field of robustness of a vehicle body structure under a vehicle collision failure condition, and in particular to a method for designing robustness of a vehicle body structure under a vehicle collision failure condition. Background Art

[0002] The high-speed collision process of automobiles is a typical nonlinear mechanical problem, which includes structural nonlinearity, material nonlinearity and contact nonlinearity. It is one of the internationally recognized difficult problems in vehicle performance design. In automobile collision tests, especially in the 25% small offset collision condition of frontal collision, due to the huge collision energy and tricky collision angle, it is easy to cause the front anti-collision beam to break and fail, the subframe connection bolts to fail, the powertrain suspension to break and fail, the steering knuckle connection point to fail, and the swing arm connection point to fail, which in turn affects the vehicle's motion posture and has a significant impact on the robustness design of the vehicle body structure. The entire collision process lasts no more than 120ms, and the above failure phenomena cannot maintain a continuous and stable state, that is, each failure point may fail or not fail, and a certain connection point may fail at 35ms or 40ms. Therefore, these uncertain factors bring great challenges to the robustness design of the vehicle body structure. At present, the industry generally adopts the failure study of mechanical properties (structural nonlinearity, material nonlinearity) for a certain failure point, and substitutes the results of local tests and simulations into the whole vehicle collision environment to simulate and predict the structural robustness of the whole vehicle collision.

[0003] Existing technology: In the 25% small offset frontal collision condition of the car, due to the huge collision energy and tricky collision angle, it is easy to cause the front anti-collision beam to break and fail, the subframe connection bolts to fail, the powertrain suspension to break and fail, the steering knuckle connection point to fail, the swing arm connection point to fail, etc., which in turn affects the vehicle's motion posture and has a significant impact on the design of the body structure robustness. At present, the industry mostly uses the mechanical properties (structural nonlinearity, material nonlinearity) of a certain failure point to substitute into the vehicle CAE model to predict the body structure robustness of the whole vehicle collision. However, the high-speed collision process of the car also includes contact nonlinear mechanics problems. Substituting the mechanical properties of a certain failure point into the vehicle CAE model cannot fully and accurately predict the vehicle's motion posture and body structure integrity.

[0004] The above method uses a mechanical performance failure study for a certain failure point, and substitutes the results of local tests and simulations into the whole vehicle collision environment to simulate and predict the structural robustness of the whole vehicle collision. Its disadvantage is that when the local failure mechanical performance parameters are substituted into the whole vehicle collision CAE model, the influence of contact nonlinearity on the whole vehicle collision result cannot be considered, that is, the robustness of the body structure design scheme cannot be accurately verified. The present invention proposes a body structure robustness design method that considers the combined influence of collision failure for automobile high-speed collision conditions. Summary of the invention

[0005] The purpose of the present invention is to solve at least one of the technical problems existing in the prior art and to provide a method for designing the robustness of the vehicle body structure under automobile collision failure conditions. The present invention studies a large number of 25% small offset collision conditions and finds that the fracture moments at various positions are concentrated between 35ms and 50ms. A CAE analysis matrix is ​​defined according to different positions and different fracture moments, and the robustness of the vehicle body structure design scheme is verified when different fracture moment combinations are used.

[0006] To achieve the above object, a method for designing the robustness of a vehicle body structure under a vehicle collision failure condition is provided, comprising the following steps:

[0007] S1: First, analyze the collision video, frame by frame, with a 25% small offset frontal collision video;

[0008] S2: Then select the failure position, assuming that the impact side of the frontal 25% small offset collision is on the left side of the vehicle;

[0009] S3: With the definition of the analysis matrix;

[0010] S4: further batch-generate the vehicle collision CAE calculation model;

[0011] S5: The calculation is then submitted;

[0012] S6: Finally verify the stability of the vehicle body structure design.

[0013] According to the method for designing the robustness of a vehicle body structure under a vehicle collision failure condition, the step S1 is not limited to analyzing the collision video of the designed vehicle.

[0014] According to the method for designing the robustness of the vehicle body structure under the conditions of automobile collision failure, in the step S2, the locations where failure occurs during the collision are selected, such as the failure of the front anti-collision beam fracture, the failure of the subframe connecting bolts, the failure of the powertrain suspension fracture, the failure of the steering knuckle connection point, the failure of the swing arm connection point, etc., and these possible failure locations are numbered.

[0015] According to the method for robustness design of vehicle body structure under automobile collision failure conditions, the analysis matrix considering collision failure combinations is defined in step S3.

[0016] According to the method for designing the robustness of a vehicle body structure under automobile collision failure conditions, the calculation results extracted in step S6 are mainly the deformation and intrusion of key collision areas of the vehicle body structure, so as to verify the robustness of the vehicle body structure design scheme.

[0017] According to the method for designing the robustness of the vehicle body structure under automobile collision failure conditions, the failure positions in the step S2 include: the left upper swing arm connection point, the left steering rod connection point, the left lower swing arm connection point, the left lateral stabilizer bar connection point, the left lower swing arm rear connection point, the left lower swing arm front connection point, the left upper swing arm rear connection point, and the left upper swing arm front connection point.

[0018] According to the method for designing the robustness of a vehicle body structure under a vehicle collision failure condition, the step S1 can also analyze collision videos of similar vehicles on the market.

[0019] According to the method for designing the robustness of a vehicle body structure under vehicle collision failure conditions, the material and size of the longitudinal beam to be optimized need to be determined before step S1. The material of the longitudinal beam is usually high-strength steel or aluminum alloy, and its size also needs to be optimized according to the vehicle model and vehicle body structure.

[0020] According to the method for designing the robustness of the vehicle body structure under the conditions of vehicle collision failure, in the step S1, a finite element analysis is performed on the longitudinal beam to determine the force distribution of the longitudinal beam during a frontal collision. The analysis should cover different collision conditions within the entire vehicle speed range to ensure that the longitudinal beam has good anti-collision capability.

[0021] According to the method for designing the robustness of the vehicle body structure under the conditions of automobile collision failure, in the step S1, on the basis of analysis, the longitudinal beam structure is optimized, and methods such as shape optimization and topology optimization can be used. Shape optimization can be achieved by changing the cross-sectional shape and bending angle of the longitudinal beam, and topology optimization can improve the strength of the longitudinal beam by adding local reinforcement ribs.

[0022] According to the method for designing the robustness of the vehicle body structure under automobile collision failure conditions, in the step S1, finite element analysis and actual tests are performed on the optimized longitudinal beam. Through finite element analysis under various load conditions, it is verified whether the strength and stability of the longitudinal beam under different conditions are effectively improved. At the same time, actual tests are performed to verify the authenticity of the finite element analysis to ensure that the optimized longitudinal beam has higher safety.

[0023] The above scheme has at least one of the following beneficial effects: the present invention has low cost (no need to perform mechanical property testing of local failure positions), can respond quickly (a large number of calculation cases are designed to quickly obtain deformation verification results of key positions of the vehicle body), and is structurally reliable (the designed vehicle body structure can meet the 25% small offset frontal collision requirements under any collision failure combination).

[0024] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present invention is further described below in conjunction with the accompanying drawings and embodiments;

[0026] Figure 1 This is a flow chart of the vehicle body structure robustness design method of the present invention;

[0027] Figure 2 for Figure 1 Schematic diagram of possible failure locations;

[0028] Figure 3 This is a schematic diagram of the deformation part of the vehicle body of the present invention;

[0029] Figure 4 A comparison diagram of the deceleration curve below the B-pillar of the vehicle body of the present invention between the simulation and the test results;

[0030] Figure 5 It is a schematic diagram of the front anti-collision beam inner plate, energy absorption box outer plate, etc. of the present invention. DETAILED DESCRIPTION

[0031] This section will describe in detail the specific embodiments of the present invention. The preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the accompanying drawings is to supplement the description of the text part of the specification with graphics, so that people can intuitively and vividly understand each technical feature and the overall technical solution of the present invention, but it cannot be understood as a limitation on the scope of protection of the present invention.

[0032] Embodiment 1

[0033] Reference Figures 1 to 5 The embodiment of the present invention provides a method for designing the robustness of a vehicle body structure under a vehicle collision failure condition, which comprises the following steps:

[0034] S1: First, analyze the collision video, frame by frame, with a 25% small offset frontal collision video;

[0035] S2: Then select the failure position, assuming that the impact side of the frontal 25% small offset collision is on the left side of the vehicle;

[0036] S3: With the definition of the analysis matrix;

[0037] S4: further batch-generate the vehicle collision CAE calculation model;

[0038] S5: The calculation is then submitted;

[0039] S6: Finally verify the stability of the vehicle body structure design.

[0040] In the present invention, step S1 is not limited to analyzing the collision video of the designed vehicle. In step S2, the locations where failure occurs during the collision are selected, such as the failure of the front anti-collision beam fracture, the failure of the subframe connection bolts, the failure of the powertrain suspension fracture, the failure of the steering knuckle connection point, the failure of the swing arm connection point, etc., and these possible failure locations are numbered;

[0041] In the present invention, the calculation results extracted in step S6 are mainly the deformation and intrusion of the key collision area of ​​the vehicle body structure, which verifies the robustness of the vehicle body structure design. The failure positions in step S2 are: the left upper swing arm connection point, the left steering rod connection point, the left lower swing arm connection point, the left lateral stabilizer bar connection point, the left lower swing arm rear connection point, the left lower swing arm front connection point, the left upper swing arm rear connection point, and the left upper swing arm front connection point. In step S1, the collision videos of the same type of vehicles on the market can also be analyzed.

[0042] The present invention has low cost (no need to perform mechanical property testing of local failure positions), fast response (a large number of calculation cases are designed to quickly obtain deformation verification results of key positions of the vehicle body), and reliable structure (the designed vehicle body structure can meet the 25% small offset frontal collision requirement under any collision failure combination).

[0043] In this embodiment, before step S1, the material and size of the longitudinal beam to be optimized need to be determined. The material of the longitudinal beam is usually high-strength steel or aluminum alloy, and its size also needs to be optimized according to the vehicle model and vehicle body structure;

[0044] In step S1 of this embodiment, a finite element analysis is performed on the longitudinal beam to determine the force distribution of the longitudinal beam during a frontal collision. The analysis should cover different collision conditions within the entire vehicle speed range to ensure that the longitudinal beam has good anti-collision capability.

[0045] In step S1 of this embodiment, based on the analysis, the longitudinal beam structure is optimized, and methods such as shape optimization and topology optimization can be used. Shape optimization can be achieved by changing the cross-sectional shape and bending angle of the longitudinal beam, and topology optimization can improve the strength of the longitudinal beam by adding local reinforcement ribs.

[0046] In step S1 of this embodiment, finite element analysis and actual tests are performed on the optimized longitudinal beam. Through finite element analysis under various load conditions, it is verified whether the strength and stability of the longitudinal beam under different conditions are effectively improved. At the same time, actual tests are performed to verify the authenticity of the finite element analysis to ensure that the optimized longitudinal beam has higher safety.

[0047] The present invention studies a large number of 25% small offset collision conditions and finds that the fracture moments at various positions are concentrated between 35ms and 50ms. A CAE analysis matrix is ​​defined according to different positions and different fracture moments, and the robustness of the vehicle body structure design scheme is verified when different fracture moment combinations are used.

[0048]

[0049]

[0050] Possible failure locations

[0051] Analysis matrix description: Taking case 1 as an example, it is assumed that the 8 positions A to H are not failed for CAE model setting, while case 2 assumes that position A is Figure 2 The left upper swing arm connection point shown in the figure breaks and fails at 45ms, and the same applies to other cases. After the calculation and verification of case 1 to case 37 is completed, it is also necessary to randomly verify whether the calculation results of the failure at positions A to H at 50ms meet the requirements. Figure 4 The requirements for the intrusion amount at the key positions are shown. At the same time, if the computing resources are sufficient and the computing time allows, the failure moment can be divided into every 1ms for verification.

[0052] In this embodiment, the A-pillar lower hinge, left footrest, left footboard and brake pedal are rated as follows: G (excellent) ≤ 150, A (good) ≤ 226, M (general) ≤ 300, P (poor) > 300, and the case calculation results are: 47.1, 37.1, 40.1 and 522.5.

[0053] Analysis matrix considering collision failure combinations

[0054]

[0055] Deformation verification results of key positions of the vehicle body

[0056] In this embodiment, the threshold evaluation is: G (excellent) ≤ 50, A (good) ≤ 100, M (average) ≤ 150, P (poor) > 150, and the case calculation result is: 19.7.

[0057] In this implementation, the steering column grade assessment is: G (excellent) ≤ 50, A (good) ≤ 100, M (average) ≤ 150, P (poor) > 150, and the case calculation result is: 64.

[0058] In this implementation, the grade assessment of the A-pillar upper hinge, the upper instrument panel and the lower left instrument panel is: G (excellent) ≤ 75, A (good) ≤ 125, M (average) ≤ 175, P (poor) > 175, and the case calculation results are: 37.5, 63.4, 64.

[0059] Embodiment 2

[0060] Reference Figures 1 to 2 The embodiment of the present invention provides a method for designing the robustness of a vehicle body structure under a vehicle collision failure condition, which comprises the following steps:

[0061] S1: First, analyze the collision video, frame by frame, with a 25% small offset frontal collision video;

[0062] S2: Then select the failure position, assuming that the impact side of the frontal 25% small offset collision is on the left side of the vehicle;

[0063] S3: With the definition of the analysis matrix;

[0064] S4: further batch-generate the vehicle collision CAE calculation model;

[0065] S5: The calculation is then submitted;

[0066] S6: Finally verify the stability of the vehicle body structure design.

[0067] In the present invention, step S1 is not limited to analyzing the collision video of the designed vehicle. In step S2, the locations where failure occurs during the collision are selected, such as the failure of the front anti-collision beam fracture, the failure of the subframe connection bolts, the failure of the powertrain suspension fracture, the failure of the steering knuckle connection point, the failure of the swing arm connection point, etc., and these possible failure locations are numbered;

[0068] In the present invention, the analysis matrix considering the collision failure combination is defined in step S3:

[0069] (1) Analysis matrix considering collision failure combinations;

[0070] (2) A vehicle body structure robustness verification method that meets the requirements of a 25% small offset frontal collision.

[0071] In the present invention, the calculation results extracted in step S6 are mainly the deformation and intrusion of the key collision area of ​​the vehicle body structure, which verifies the robustness of the vehicle body structure design. The failure positions in step S2 are: the left upper swing arm connection point, the left steering rod connection point, the left lower swing arm connection point, the left lateral stabilizer bar connection point, the left lower swing arm rear connection point, the left lower swing arm front connection point, the left upper swing arm rear connection point, and the left upper swing arm front connection point. In step S1, the collision videos of the same type of vehicles on the market can also be analyzed.

[0072] The present invention has low cost (no need to perform mechanical property testing of local failure positions), fast response (a large number of calculation cases are designed to quickly obtain deformation verification results of key positions of the vehicle body), and reliable structure (the designed vehicle body structure can meet the 25% small offset frontal collision requirement under any collision failure combination).

[0073] In this embodiment, before step S1, the material and size of the longitudinal beam to be optimized need to be determined. The material of the longitudinal beam is usually high-strength steel or aluminum alloy, and its size also needs to be optimized according to the vehicle model and vehicle body structure;

[0074] In step S1 of this embodiment, a finite element analysis is performed on the longitudinal beam to determine the force distribution of the longitudinal beam during a frontal collision. The analysis should cover different collision conditions within the entire vehicle speed range to ensure that the longitudinal beam has good anti-collision capability.

[0075] In step S1 of this embodiment, based on the analysis, the longitudinal beam structure is optimized, and methods such as shape optimization and topology optimization can be used. Shape optimization can be achieved by changing the cross-sectional shape and bending angle of the longitudinal beam, and topology optimization can improve the strength of the longitudinal beam by adding local reinforcement ribs.

[0076] In step S1 of this embodiment, finite element analysis and actual tests are performed on the optimized longitudinal beam. Through finite element analysis under various load conditions, it is verified whether the strength and stability of the longitudinal beam under different conditions are effectively improved. At the same time, actual tests are performed to verify the authenticity of the finite element analysis to ensure that the optimized longitudinal beam has higher safety.

[0077] The present invention studies a large number of 25% small offset collision conditions and finds that the fracture moments at various positions are concentrated between 35ms and 50ms. A CAE analysis matrix is ​​defined according to different positions and different fracture moments, and the robustness of the vehicle body structure design scheme is verified when different fracture moment combinations are used.

[0078] Step 1: Analyze the 25% small offset frontal collision video frame by frame. It is not limited to analyzing the collision video of the designed vehicle, but also can analyze the collision video of the same type of vehicles on the market (for details, please search the official website of IIHS or CIASI);

[0079] Step 2: Assume that the impact side of the frontal 25% small offset collision is on the left side of the vehicle, select the locations where failure occurs during the collision, such as the front anti-collision beam fracture failure, subframe connection bolt failure, powertrain suspension fracture failure, steering knuckle connection point failure, swing arm connection point failure, etc., and number these possible failure locations;

[0080] Step 3: Define the analysis matrix considering the collision failure combination;

[0081] Step 4: Batch generate vehicle collision CAE calculation model;

[0082] Step 5: Submit the calculation;

[0083] Step 6: Extract the calculation results, mainly the deformation and intrusion of the key collision areas of the body structure, to verify the robustness of the body structure design.

[0084] Embodiment 3

[0085] Reference Figures 1 to 5 The embodiment of the present invention provides a method for designing the robustness of a vehicle body structure under a vehicle collision failure condition, which comprises the following steps:

[0086] S1: First, analyze the collision video, frame by frame, with a 25% small offset frontal collision video;

[0087] S2: Then select the failure position, assuming that the impact side of the frontal 25% small offset collision is on the left side of the vehicle;

[0088] S3: With the definition of the analysis matrix;

[0089] S4: further batch-generate the vehicle collision CAE calculation model;

[0090] S5: The calculation is then submitted;

[0091] S6: Finally verify the stability of the vehicle body structure design.

[0092] In the present invention, step S1 is not limited to analyzing the collision video of the designed vehicle. In step S2, the locations where failure occurs during the collision are selected, such as the failure of the front anti-collision beam fracture, the failure of the subframe connection bolts, the failure of the powertrain suspension fracture, the failure of the steering knuckle connection point, the failure of the swing arm connection point, etc., and these possible failure locations are numbered;

[0093] In the present invention, the calculation results extracted in step S6 are mainly the deformation and intrusion of the key collision area of ​​the vehicle body structure, which verifies the robustness of the vehicle body structure design. The failure positions in step S2 are: the left upper swing arm connection point, the left steering rod connection point, the left lower swing arm connection point, the left lateral stabilizer bar connection point, the left lower swing arm rear connection point, the left lower swing arm front connection point, the left upper swing arm rear connection point, and the left upper swing arm front connection point. In step S1, the collision videos of the same type of vehicles on the market can also be analyzed.

[0094] The present invention has low cost (no need to perform mechanical property testing of local failure positions), fast response (a large number of calculation cases are designed to quickly obtain deformation verification results of key positions of the vehicle body), and reliable structure (the designed vehicle body structure can meet the 25% small offset frontal collision requirement under any collision failure combination).

[0095] In this embodiment, before step S1, the material and size of the longitudinal beam to be optimized need to be determined. The material of the longitudinal beam is usually high-strength steel or aluminum alloy, and its size also needs to be optimized according to the vehicle model and vehicle body structure;

[0096] In step S1 of this embodiment, a finite element analysis is performed on the longitudinal beam to determine the force distribution of the longitudinal beam during a frontal collision. The analysis should cover different collision conditions within the entire vehicle speed range to ensure that the longitudinal beam has good anti-collision capability.

[0097] In step S1 of this embodiment, based on the analysis, the longitudinal beam structure is optimized, and methods such as shape optimization and topology optimization can be used. Shape optimization can be achieved by changing the cross-sectional shape and bending angle of the longitudinal beam, and topology optimization can improve the strength of the longitudinal beam by adding local reinforcement ribs.

[0098] In step S1 of this embodiment, finite element analysis and actual tests are performed on the optimized longitudinal beam. Through finite element analysis under various load conditions, it is verified whether the strength and stability of the longitudinal beam under different conditions are effectively improved. At the same time, actual tests are performed to verify the authenticity of the finite element analysis to ensure that the optimized longitudinal beam has higher safety.

[0099] The present invention studies a large number of 25% small offset collision conditions and finds that the fracture moments at various positions are concentrated between 35ms and 50ms. A CAE analysis matrix is ​​defined according to different positions and different fracture moments, and the robustness of the vehicle body structure design scheme is verified when different fracture moment combinations are used.

[0100] In this embodiment, the offset collision simulation modeling and test verification of the vehicle with 40% overlap are as follows:

[0101] In order to study the structural crashworthiness of a certain vehicle model under 40% overlap offset collision conditions, a finite element model of the whole vehicle and a deformable barrier was established. To verify the accuracy of the model, the simulation results were compared with the test results of the real vehicle collision. The schematic diagram of the body deformation is shown in the figure above. It can be seen that the body deformation parts and deformation modes of the two are basically the same, and the movement postures are basically the same.

[0102] The comparison of the deceleration curves below the B-pillar of the vehicle body between the simulation and the test results is shown in the figure above. As can be seen from the figure, the deceleration change trends below the B-pillar of the vehicle body are basically consistent, and the peak values ​​are roughly the same. Based on engineering experience, it can be judged that the simulation model has high accuracy and can be used for subsequent structural crashworthiness optimization design.

[0103] Embodiment 4:

[0104] Reference Figures 1 to 5The embodiment of the present invention provides a method for designing the robustness of a vehicle body structure under a vehicle collision failure condition, which comprises the following steps:

[0105] S1: First, analyze the collision video, frame by frame, with a 25% small offset frontal collision video;

[0106] S2: Then select the failure position, assuming that the impact side of the frontal 25% small offset collision is on the left side of the vehicle;

[0107] S3: With the definition of the analysis matrix;

[0108] S4: further batch-generate the vehicle collision CAE calculation model;

[0109] S5: The calculation is then submitted;

[0110] S6: Finally verify the stability of the vehicle body structure design.

[0111] In the present invention, step S1 is not limited to analyzing the collision video of the designed vehicle. In step S2, the locations where failure occurs during the collision are selected, such as the failure of the front anti-collision beam fracture, the failure of the subframe connection bolts, the failure of the powertrain suspension fracture, the failure of the steering knuckle connection point, the failure of the swing arm connection point, etc., and these possible failure locations are numbered;

[0112] In the present invention, the calculation results extracted in step S6 are mainly the deformation and intrusion of the key collision area of ​​the vehicle body structure, which verifies the robustness of the vehicle body structure design. The failure positions in step S2 are: the left upper swing arm connection point, the left steering rod connection point, the left lower swing arm connection point, the left lateral stabilizer bar connection point, the left lower swing arm rear connection point, the left lower swing arm front connection point, the left upper swing arm rear connection point, and the left upper swing arm front connection point. In step S1, the collision videos of the same type of vehicles on the market can also be analyzed.

[0113] The present invention has low cost (no need to perform mechanical property testing of local failure positions), fast response (a large number of calculation cases are designed to quickly obtain deformation verification results of key positions of the vehicle body), and reliable structure (the designed vehicle body structure can meet the 25% small offset frontal collision requirement under any collision failure combination).

[0114] The present invention studies a large number of 25% small offset collision conditions and finds that the fracture moments at various positions are concentrated between 35ms and 50ms. A CAE analysis matrix is ​​defined according to different positions and different fracture moments, and the robustness of the vehicle body structure design scheme is verified when different fracture moment combinations are used.

[0115] In this embodiment, before step S1, the material and size of the longitudinal beam to be optimized need to be determined. The material of the longitudinal beam is usually high-strength steel or aluminum alloy, and its size also needs to be optimized according to the vehicle model and vehicle body structure;

[0116] In step S1 of this embodiment, a finite element analysis is performed on the longitudinal beam to determine the force distribution of the longitudinal beam during a frontal collision. The analysis should cover different collision conditions within the entire vehicle speed range to ensure that the longitudinal beam has good anti-collision capability.

[0117] In step S1 of this embodiment, based on the analysis, the longitudinal beam structure is optimized, and methods such as shape optimization and topology optimization can be used. Shape optimization can be achieved by changing the cross-sectional shape and bending angle of the longitudinal beam, and topology optimization can improve the strength of the longitudinal beam by adding local reinforcement ribs.

[0118] In step S1 of this embodiment, finite element analysis and actual tests are performed on the optimized longitudinal beam. Through finite element analysis under various load conditions, it is verified whether the strength and stability of the longitudinal beam under different conditions are effectively improved. At the same time, actual tests are performed to verify the authenticity of the finite element analysis to ensure that the optimized longitudinal beam has higher safety.

[0119] Considering the importance of each component in the front-end structure of this vehicle model in the offset collision process, the sheet thickness of 12 components was finally selected as the design variables. Due to the symmetry of the structure, it is further simplified into 7 design variables as shown in the figure below, represented by x1~x7, which are the thickness of the 7 panels to be optimized, namely the front bumper beam outer panel, the front bumper beam inner panel, the energy absorption box outer panel, the energy absorption box inner panel, the middle front longitudinal beam outer panel, the rear front longitudinal beam outer panel and the front longitudinal beam inner panel. At the same time, when considering the uncertainty of the design variables, it is assumed that the 7 design variables are all normally distributed, and based on the typical processing accuracy and assembly error, the coefficient of variation of the design variables σ / μ (where σ is the standard deviation and μ is the mean) is set to 5% [7]. The initial values ​​and probability distribution of the design variables are shown in the following table.

[0120]

[0121] The support vector regression (SVR) model is an extension of the support vector machine in the field of regression. Its basic idea is to find an appropriate prediction function and use the maximum margin criterion to divide the original data into two categories. When the sample point data is linearly inseparable, the kernel function method must be used. The kernel function is essentially a mapping. When different kernel functions are selected, the sample data will be mapped to different spaces, and the prediction values ​​of the SVR model will also be different. At this time, the form of the support vector regression model [8] is:

[0122]

[0123] Where: K(xi, x) is the kernel function; N is the number of sample points; αi and are Lagrange multipliers for different constraints; b is the threshold. According to the structural risk minimization rule, solving the function f(x) can be transformed into the following optimization problem [9]:

[0124]

[0125] Where: w is the boundary and w>0; C is the balance factor that controls the complexity of f(x); c(ξi) and c(ξi*) are loss functions; yi is the response value of the sample point for training the SVR model; ξi and ξi* are relaxation factors; ε is the parameter of the insensitive loss function.

[0126] In this embodiment, the front deformation zone is designed as follows: a certain deformation zone is set in front of the longitudinal beam, so that the impact force of the car can be dispersed to a wider range when a collision occurs, thereby reducing the force in the car compartment.

[0127] In this embodiment, the cushioning material is reinforced: cushioning material is added to the nose and front bumper of the car to absorb the impact energy during a collision and reduce the stress inside the car.

[0128] In the present embodiment, the airbag is designed so that when a car collides, the airbag can be rapidly deployed and form a certain cushioning effect to reduce the damage to the passengers.

[0129] In this embodiment, the anti-tension rod is designed to disperse the force in the vehicle body to a wider range when the vehicle collides, thereby protecting the safety of the passengers.

[0130] The present invention studies a large number of 25% small offset collision conditions and finds that the fracture moments at various positions are concentrated between 35ms and 50ms. A CAE analysis matrix is ​​defined according to different positions and different fracture moments, and the robustness of the vehicle body structure design scheme is verified when different fracture moment combinations are used.

[0131] The embodiments of the present invention are described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Various changes can be made within the knowledge scope of ordinary technicians in the technical field without departing from the purpose of the present invention.

[0132] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for designing the robustness of a vehicle body structure under vehicle collision failure conditions, characterized in that: The following steps are involved: S1: First, analyze the collision video, frame by frame, for a frontal collision with a small offset of 25%. S2: Then select the failure location, assuming that the impact side of a 25% frontal small offset collision is on the left side of the vehicle; S3: With the definition of the analysis matrix; S4: Batch generate vehicle collision CAE calculation models; S5: The calculation is then submitted; S6: Finally verify the stability of the vehicle body structure design.

2. The method for designing the robustness of a vehicle body structure under vehicle collision failure conditions according to claim 1, characterized in that: The step S1 is not limited to analyzing the collision video of the designed vehicle.

3. The method for designing the robustness of a vehicle body structure under vehicle collision failure conditions according to claim 1, characterized in that: In the step S2, the locations where failure occurs during the collision are selected, such as the failure of the front anti-collision beam fracture, the failure of the subframe connecting bolts, the failure of the powertrain suspension fracture, the failure of the steering knuckle connection point, the failure of the swing arm connection point, etc., and these possible failure locations are numbered. The failure locations in the step S2 are: the left upper swing arm connection point, the left steering rod connection point, the left lower swing arm connection point, the left lateral stabilizer bar connection point, the left lower swing arm rear connection point, the left lower swing arm front connection point, the left upper swing arm rear connection point, and the left upper swing arm front connection point.

4. The method for designing the robustness of a vehicle body structure under vehicle collision failure conditions according to claim 1, characterized in that: In step S3, an analysis matrix considering collision failure combinations is defined.

5. The method for designing the robustness of a vehicle body structure under vehicle collision failure conditions according to claim 1, characterized in that: The calculation results extracted in step S6 are mainly the deformation and intrusion of key collision areas of the vehicle body structure, which verify the robustness of the vehicle body structure design scheme.

6. The method for designing the robustness of a vehicle body structure under vehicle collision failure conditions according to claim 1, characterized in that: In step S1, collision videos of similar vehicles on the market can also be analyzed.

7. The method for designing the robustness of a vehicle body structure under vehicle collision failure conditions according to claim 1, characterized in that: Before step S1, the material and size of the longitudinal beam to be optimized need to be determined. The material of the longitudinal beam is usually high-strength steel or aluminum alloy, and its size also needs to be optimized according to the vehicle model and body structure.

8. The method for designing the robustness of a vehicle body structure under vehicle collision failure conditions according to claim 7, characterized in that: In step S1, a finite element analysis is performed on the longitudinal beam to determine the force distribution of the longitudinal beam during a frontal collision. The analysis should cover different collision conditions within the entire vehicle speed range to ensure that the longitudinal beam has good collision resistance.

9. The method for designing the robustness of a vehicle body structure under vehicle collision failure conditions according to claim 1, characterized in that: In step S1, based on the analysis, the longitudinal beam structure is optimized by using methods such as shape optimization and topology optimization. Shape optimization can be achieved by changing the cross-sectional shape and bending angle of the longitudinal beam, while topology optimization can improve the strength of the longitudinal beam by adding local reinforcement ribs.

10. The method for designing the robustness of a vehicle body structure under vehicle collision failure conditions according to claim 1, characterized in that: In step S1, finite element analysis and actual tests are performed on the optimized longitudinal beam. Through finite element analysis under various load conditions, it is verified whether the strength and stability of the longitudinal beam under different conditions have been effectively improved. At the same time, actual tests are performed to verify the authenticity of the finite element analysis to ensure that the optimized longitudinal beam has higher safety.

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