Vehicle body design method and device based on multi-working-condition topology optimization and storage medium

Abstract

The application discloses a kind of based on multi-working condition topological optimization car body design method, device and storage medium, wherein, method part includes: according to the design boundary of car body determines car body finite element model, multiple working condition loads are loaded to car body finite element model, to obtain car body topological optimization analysis model, multiple working condition loads include static stiffness working condition load, dynamic stiffness working condition load and crash working condition load;Car body topological optimization analysis model is iteratively solved to obtain the target topological optimization result satisfying multi-working condition mass optimization target, and load transfer path analysis is carried out according to the target topological optimization result, obtains the target load transfer path of car body, determines car body frame model according to target load transfer path.The present application considers stiffness, NVH and crash performance simultaneously, and a car body system satisfying the performance target of car body and a high level of lightweight can be obtained, and the design efficiency and accuracy are improved.

Description

Technical Field

[0001] This invention relates to the field of vehicle design technology, and in particular to a vehicle body design method, apparatus and storage medium based on multi-condition topology optimization. Background Technology

[0002] The vehicle body structure determines the key performance of the entire vehicle. Optimizing the body structure based on actual operating conditions while ensuring the body meets lightweight requirements is a challenge in vehicle body design. Vehicle lightweighting can be approached from three aspects: structural design, application of lightweight materials, and advanced manufacturing processes. Structural optimization includes structural dimension optimization, shape optimization, topology optimization, and multidisciplinary design optimization. For the structural optimization design of the body frame in large vehicles, the main methods used are: locally replacing traditional body structures with lightweight materials and verifying the results through finite element analysis; or using topology optimization methods, establishing local or global topology optimization models based on the original structural finite element analysis results, solving them, and finally extracting the topology optimization results to transform them into a manufacturable solution.

[0003] However, these solutions are all based on the mature design experience of existing vehicles. Newly designed vehicles differ from existing vehicles in many ways, such as powertrain, styling, and lightweight requirements. The body designed based on past design experience often has local or even global defects. The performance and lightweight of the body are difficult to achieve the target, resulting in a lot of optimization in the later stage. The design efficiency and accuracy of the body are low. Summary of the Invention

[0004] This invention provides a vehicle body design method, device, and storage medium based on multi-condition topology optimization, to solve the problem that existing vehicle body design schemes are unable to achieve both performance and lightweighting goals, resulting in low design efficiency and accuracy.

[0005] A vehicle body design method based on multi-condition topology optimization is provided, including:

[0006] The finite element model of the vehicle body is determined based on the design boundaries of the vehicle body.

[0007] Multiple load conditions are applied to the vehicle body finite element model to obtain the vehicle body topology optimization analysis model. The multiple load conditions include static stiffness load, dynamic stiffness load and collision load.

[0008] The vehicle topology optimization analysis model is iteratively solved to obtain the target topology optimization result that satisfies the quality optimization objectives under multiple working conditions.

[0009] Based on the target topology optimization results, the load transfer path of the vehicle body is analyzed to obtain the target load transfer path of the vehicle body, and the vehicle body frame model is determined based on the target load transfer path.

[0010] Furthermore, the vehicle body topology optimization analysis model is iteratively solved to obtain the target topology optimization results that satisfy the multi-condition quality optimization objectives, including:

[0011] Determine the constraints and quality optimization objectives corresponding to the static stiffness condition, dynamic stiffness condition, and collision condition;

[0012] Based on the corresponding constraints, the vehicle body topology optimization analysis model is iteratively solved to obtain sub-topology optimization results that satisfy the corresponding working condition quality optimization objectives;

[0013] The sub-topology optimization results under static stiffness, dynamic stiffness, and collision conditions are combined and solved to obtain the target topology optimization results for all quality optimization objectives.

[0014] Furthermore, the constraint conditions corresponding to the static stiffness condition, dynamic stiffness condition, and collision condition are determined, including:

[0015] The static stiffness threshold and the equivalent static stiffness threshold corresponding to the dynamic stiffness are determined based on the vehicle model requirements.

[0016] The constraints for the static stiffness condition are determined based on the static stiffness threshold, and the constraints for the dynamic stiffness condition are determined based on the equivalent static stiffness threshold.

[0017] After the collision condition is transformed into a linear static condition, it is loaded onto the vehicle body finite element model to obtain a linearized finite element compliance analysis model of the linear static condition.

[0018] The linearized finite element compliance analysis model is iteratively solved to obtain the compliance target value that meets the requirements;

[0019] The constraints for the collision conditions are determined based on the compliance target value.

[0020] Furthermore, based on the target topology optimization results, load transfer path analysis is performed on the vehicle body to obtain the target load transfer path of the vehicle body, including:

[0021] Based on the target topology optimization results, determine whether the material variable values ​​of the vehicle body material are less than the preset material variable threshold;

[0022] If the material variable value of the vehicle body material is greater than or equal to the preset material variable threshold, then the vehicle body material is retained;

[0023] Based on the distribution of the retained body materials, the optimal load transfer path of the body is determined as the target load transfer path.

[0024] Furthermore, multiple load conditions are applied to the vehicle body finite element model, including:

[0025] Determine the static stiffness load, dynamic stiffness load, and collision load;

[0026] Convert the dynamic stiffness load into an equivalent static stiffness load.

[0027] Transform the collision load into a linear static load;

[0028] The static stiffness load, equivalent static stiffness load, and linear static load are applied to the corresponding positions on the vehicle body finite element model.

[0029] Furthermore, the finite element model of the vehicle body is determined based on the design boundaries of the vehicle body, including:

[0030] The design boundaries of the vehicle body are determined based on its shape, engineering constraints, surrounding layout conditions, and vehicle requirements.

[0031] The envelope geometry model of the vehicle body is determined based on the design boundary of the vehicle body. The envelope geometry model includes the design area and the design reserved area of ​​the vehicle body. The design reserved area is the reserved space of the vehicle body determined according to the manufacturing process constraints of the vehicle body.

[0032] The envelope geometry model of the vehicle body is meshed using finite element methods to obtain the finite element model of the vehicle body.

[0033] Furthermore, the static stiffness load includes the bending stiffness load and torsional stiffness load of the vehicle body, the collision load includes the frontal collision load, side collision load, rear collision load and top pressure load of the vehicle body, and the dynamic stiffness load includes the dynamic stiffness load of all key attachment points on the vehicle body.

[0034] A vehicle body design device based on multi-condition topology optimization is provided, comprising:

[0035] The first determination module is used to determine the finite element model of the vehicle body based on the design boundaries of the vehicle body.

[0036] The second determination module is used to load multiple load conditions onto the vehicle body finite element model to obtain the vehicle body topology optimization analysis model. The multiple load conditions include static stiffness load conditions, dynamic stiffness load conditions, and collision load conditions.

[0037] The iteration module is used to iteratively solve the vehicle topology optimization analysis model to obtain the target topology optimization result that satisfies the quality optimization objectives under multiple working conditions.

[0038] The third determination module is used to analyze the load transfer path of the vehicle body based on the target topology optimization results, obtain the target load transfer path of the vehicle body, and determine the vehicle body frame model based on the target load transfer path.

[0039] A vehicle body design apparatus based on multi-condition topology optimization includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the steps of the aforementioned vehicle body design method based on multi-condition topology optimization.

[0040] A readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the above-described vehicle body design method based on multi-condition topology optimization.

[0041] In one of the solutions provided by the above-mentioned multi-condition topology optimization-based vehicle body design method, device, and storage medium, the finite element model of the vehicle body is determined according to the design boundary of the vehicle body. Then, multiple condition loads are applied to the finite element model of the vehicle body to obtain the topology optimization analysis model of the vehicle body. The multiple condition loads include static stiffness condition loads, dynamic stiffness condition loads, and collision condition loads. The topology optimization analysis model of the vehicle body is then iteratively solved to obtain the target topology optimization result that meets the multi-condition quality optimization objective. Based on the target topology optimization result, the load transfer path of the vehicle body is analyzed to obtain the target load transfer path of the vehicle body. Finally, the vehicle body frame model is determined based on the target load transfer path. In this invention, by optimizing the static stiffness, dynamic stiffness, and collision conditions of the vehicle body information, and considering the stiffness, NVH, and collision performance of the vehicle body, the structural layout of the vehicle body is made more reasonable, which can improve the target performance of the vehicle body. On this basis, quality optimization is also used as an objective for topology optimization. Based on the topology optimization result, a vehicle body frame system that meets the vehicle body performance objective and has a high level of lightweighting can be obtained, which improves the design efficiency and accuracy of the vehicle body. Attached Figure Description

[0042] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0043] Figure 1 This is a schematic diagram of an application environment for a vehicle body design method based on multi-condition topology optimization in one embodiment of the present invention;

[0044] Figure 2 This is a flowchart illustrating a vehicle body design method based on multi-condition topology optimization in one embodiment of the present invention;

[0045] Figure 3 This is a schematic diagram of the structure of the design area in one embodiment of the present invention;

[0046] Figure 4 This is a schematic diagram of the structure of the reserved area designed in one embodiment of the present invention;

[0047] Figure 5 yes Figure 2 A schematic diagram of the implementation process of step S30;

[0048] Figure 6 This is a schematic diagram of the longitudinal beam topology optimization results in one embodiment of the present invention;

[0049] Figure 7 It is based on Figure 6 A schematic diagram of the longitudinal beam structure obtained from the analysis of the longitudinal beam topology optimization results;

[0050] Figure 8 This is a schematic diagram of the beam topology optimization result in one embodiment of the present invention;

[0051] Figure 9 It is based on Figure 8 A schematic diagram of the beam structure obtained from the analysis of the beam topology optimization results;

[0052] Figure 10 This is a schematic diagram of a vehicle body design device based on multi-condition topology optimization in one embodiment of the present invention;

[0053] Figure 11 This is another structural schematic diagram of a vehicle body design device based on multi-condition topology optimization in one embodiment of the present invention. Detailed Implementation

[0054] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0055] The vehicle body design method based on multi-condition topology optimization provided in this invention can be applied to, for example... Figure 1In this application environment, the terminal device communicates with the server via a network. The terminal device sends information such as the vehicle body design boundaries and multiple load conditions to the server. The server determines the vehicle body finite element model based on the design boundaries, and then loads multiple load conditions onto the vehicle body finite element model to obtain the vehicle body topology optimization analysis model. The multiple load conditions include static stiffness load, dynamic stiffness load, and collision load. The vehicle body topology optimization analysis model is then iteratively solved to obtain the target topology optimization result that meets the multi-condition quality optimization objective. Based on the target topology optimization result, the load transfer path of the vehicle body is analyzed to obtain the target load transfer path of the vehicle body. Finally, the vehicle body frame model is determined based on the target load transfer path. By optimizing the vehicle body's static stiffness, dynamic stiffness, and collision conditions, while considering the vehicle body's stiffness, NVH, and collision performance, the structural layout of the vehicle body is made more reasonable, which can improve the target performance of the vehicle body. On this basis, quality optimization is also used as an objective for topology optimization. Based on the topology optimization result, a vehicle body frame system that meets the vehicle body performance objective and has a high level of lightweighting can be obtained, which improves the design efficiency and accuracy of the vehicle body.

[0056] The terminal devices can be, but are not limited to, various personal computers, laptops, smartphones, tablets, etc. Servers can be implemented using standalone servers or server clusters composed of multiple servers.

[0057] In one embodiment, such as Figure 2 As shown, a vehicle body design method based on multi-condition topology optimization is provided, which is then applied to... Figure 1 Taking the server in the example, the following steps are included:

[0058] S10: Determine the finite element model of the vehicle body based on the design boundaries of the vehicle body.

[0059] After acquiring input information such as the vehicle body's shape, engineering constraints, surrounding layout conditions, and vehicle requirements, the server determines the vehicle body's design boundaries based on these inputs, and then determines the vehicle body's finite element model based on these design boundaries.

[0060] The design boundary refers to the boundary of each structure in the vehicle body. The region where each structure is located can be determined based on the boundary of each structure in the vehicle body. The finite element model of the vehicle body includes the design region and the design reserved region (non-design region). The design region is the region in the vehicle body where the structure that needs to be optimized is located, while the design reserved region is the region in the vehicle body where non-optimized structures such as peripheral matching areas with specific requirements, fixed points, restrictions on changes, and clearly defined areas are located.

[0061] Among them, such as Figure 3As shown, the design area includes the front nacelle assembly (1), front floor assembly (2), rear floor assembly (3), left side panel assembly (4), roof assembly (5), and other assembly structures and their components. Figure 4 As shown, the design reserved area includes, but is not limited to, the space requirements for the arrangement of structures such as door openings (6), engine assembly (7) (engine, transmission, fuel tank), front / rear tire envelopes (8, 9), and front / rear suspension envelopes (10, 11). The actual design reserved area is determined according to the design requirements of the target vehicle model. In addition, structures that have been clearly defined, such as the central tunnel, A-pillar, and B-pillar, can also be used as design reserved areas.

[0062] S20: Apply multiple load conditions to the vehicle body finite element model to obtain the vehicle body topology optimization analysis model.

[0063] The server will also acquire multiple load conditions. After determining the finite element model of the vehicle body based on its design boundaries, the server will apply these load conditions to the finite element model to obtain a topology optimization analysis model for the vehicle body. These load conditions include static stiffness load conditions, dynamic stiffness load conditions, and collision load conditions.

[0064] S30: Iteratively solve the vehicle body topology optimization analysis model to obtain the target topology optimization result that satisfies the quality optimization objectives under multiple working conditions.

[0065] After obtaining the vehicle body topology optimization analysis model, it is necessary to iteratively solve the model. During the iteration process, it is necessary to determine whether the optimization analysis result converges (satisfies the multi-condition quality optimization objective), whether the structure is reasonable, and whether the structural force transmission path is clear. If the optimization analysis result converges, the structure is reasonable, and the force transmission path is clear, then the optimization analysis result is taken as the target topology optimization result that satisfies the multi-condition quality optimization objective. Otherwise, different optimization settings (design area, multi-condition optimization settings, etc.) are adjusted and compared until the target topology optimization result that satisfies the multi-condition quality optimization objective is obtained.

[0066] For example, if the quality optimization objective can be to minimize the mass, then after obtaining the vehicle body topology optimization analysis model, it is necessary to iteratively solve the vehicle body topology optimization analysis model. During the iteration process, if it is determined that the optimization analysis result converges, then it is determined that the currently set vehicle body structure meets the multi-condition quality optimization objective. When the optimization analysis result converges, the structure is reasonable and the force transmission path is clear, then the optimization analysis result is taken as the target topology optimization result that meets the multi-condition quality optimization objective.

[0067] S40: Based on the target topology optimization results, perform load transfer path analysis on the vehicle body to obtain the target load transfer path of the vehicle body, and determine the vehicle body frame model based on the target load transfer path.

[0068] After obtaining the target topology optimization results that meet the quality optimization objectives under multiple working conditions, the server needs to interpret the optimization results to determine the optimal load transfer path of the vehicle body, which is then used as the target load transfer path of the vehicle body. This involves combining engineering feasibility with the target topology optimization results to analyze the load transfer path of the vehicle body and obtain the target load transfer path. Finally, the vehicle body frame model is determined based on the target load transfer path.

[0069] In this embodiment, the vehicle frame model can be a body-in-white model. That is, after obtaining the target topology optimization result that meets the multi-condition quality optimization objective, the server combines engineering feasibility and analyzes the load transfer path of the vehicle body according to the target topology optimization result to obtain the target load transfer path of the vehicle body. Finally, the body-in-white model is determined according to the target load transfer path so that the body-in-white of the target vehicle model can be directly manufactured according to the body-in-white model.

[0070] It's important to understand that static stiffness is the ability to resist deformation under static loads, while dynamic stiffness is the ability to resist deformation under dynamic loads, also known as the dynamic force required to induce a unit amplitude of vibration. The dynamic stiffness of the vehicle body is a key indicator for describing vibration reduction performance. By applying static stiffness loads, dynamic stiffness loads, and collision loads to the vehicle body finite element model, and obtaining the vehicle body topology optimization analysis model, we can optimize the stiffness, NVH performance, and collision performance of the vehicle body under multiple operating conditions. This results in a compliant vehicle body frame model, fundamentally ensuring the overall performance levels of the vehicle. Furthermore, because multiple operating condition quality optimization objectives are used as convergence targets during the iterative solution of the vehicle body topology optimization analysis model, the vehicle body's structural optimization maximizes the achievement of lightweighting goals. Subsequently, load transfer path analysis is performed on the vehicle body based on the target topology optimization results to obtain the target load transfer path, further ensuring the structural rationality and lightweighting of the vehicle body.

[0071] In this embodiment, load transfer path analysis is performed based on topology optimization technology, eliminating the reliance on and limitations of manual experience. This allows the vehicle frame model to more accurately and comprehensively meet design requirements, achieving intelligent optimization of the solution. By optimizing the static stiffness, dynamic stiffness, and collision performance of the vehicle body information under multiple conditions, while simultaneously considering the stiffness, NVH, and collision performance, the structural layout of the vehicle body is made more reasonable. Consequently, the static stiffness, dynamic stiffness, and collision resistance of the vehicle system obtained from the vehicle frame model are significantly improved. In addition to improving the target performance of the vehicle body, topology optimization is also performed with mass optimization as the objective. Based on the topology optimization results, a vehicle system that meets the vehicle performance targets and achieves a high level of lightweighting can be obtained. Ultimately, a vehicle system that meets the vehicle performance targets and achieves a high level of lightweighting can be obtained without repeatedly optimizing design components, thereby improving the design efficiency and accuracy of the vehicle body.

[0072] In one embodiment, step S10, which involves determining the finite element model of the vehicle body based on the design boundaries of the vehicle body, specifically includes the following steps:

[0073] S11: Determine the design boundaries of the vehicle body based on its shape, engineering constraints, surrounding layout conditions, and vehicle requirements.

[0074] The system acquires input information such as the vehicle body's styling (including interior and exterior styling), human-machine space, engineering constraints, surrounding layout conditions, and vehicle requirements. Then, based on the vehicle body's styling, engineering constraints, surrounding layout conditions, and vehicle requirements, it determines the design boundaries of the vehicle body.

[0075] S12: Determine the envelope geometry model of the vehicle body based on the design boundaries of the vehicle body.

[0076] After determining the design boundaries of the vehicle body, the envelope geometry model of the vehicle body is determined based on the design boundaries of the interior and exterior styling, human-machine space, and overall layout. This results in a refined and reliable envelope model of the vehicle body structure, and the optimization results obtained are highly targeted.

[0077] The envelope geometry model includes the design area and the design reserved area (non-design area) of the vehicle body. The design area is the area in the vehicle body where the structure that needs to be optimized is located, and the design reserved area is the reserved space in the vehicle body determined according to the manufacturing process constraints of the vehicle body. In other words, the design reserved area is the area in the vehicle body where there are specific requirements for the surrounding matching area, fixed points, restrictions on changes, and clearly defined non-optimized structures.

[0078] The reasonable definition of the design area has a great impact on the result of the optimization path. It is necessary to consider the layout space in detail and confirm it through design. The detail here does not refer to the dimensional accuracy requirements, but rather to the inclusion of all possible distributions of the optimized structure without reserving too much space for non-layout areas.

[0079] S13: Perform finite element mesh generation on the envelope geometry model of the vehicle body to obtain a finite element model of the vehicle body.

[0080] After determining the envelope geometry model of the vehicle body based on the design boundaries, the envelope geometry model of the vehicle body is meshed using finite element methods to obtain a finite element model of the vehicle body.

[0081] In this embodiment, the design boundary of the vehicle body is first determined based on the vehicle body's shape, engineering constraints, surrounding layout conditions, and vehicle requirements. Then, the envelope geometry model of the vehicle body is determined based on the design boundary. Finally, the envelope geometry model of the vehicle body is meshed using finite element methods to obtain the finite element model of the vehicle body. This clarifies the specific process of determining the finite element model of the vehicle body based on its design boundary. The design reserved area is determined based on the manufacturing constraints (engineering constraints) of the vehicle body, thereby obtaining the finite element model of the vehicle body. The definition of manufacturing constraints is realized by using the reserved design space method. When iteratively solving the model of the vehicle body in the subsequent process, the influence of manufacturing constraints on the actual vehicle body is considered, making the arrangement and distribution of the vehicle body structural beams more reasonable.

[0082] In one embodiment, the static stiffness load includes the bending stiffness load and torsional stiffness load of the vehicle body. The bending stiffness load and torsional stiffness load are applied to the finite element model of the vehicle body and solved iteratively, resulting in good bending and torsional static stiffness performance of the obtained vehicle body. The collision load includes the frontal collision load, side collision load, rear collision load, and roof pressure load of the vehicle body. The frontal collision load, side collision load, rear collision load, and roof pressure load are applied to the finite element model of the vehicle body and solved iteratively, resulting in good multi-directional collision resistance performance of the obtained vehicle body. The dynamic stiffness load includes the dynamic stiffness load of all key attachment points on the vehicle body. The dynamic stiffness load of all key attachment points is applied to the finite element model of the vehicle body and solved iteratively, resulting in good vibration resistance of the obtained vehicle body and improved NVH performance.

[0083] In one embodiment, step S20, which involves loading multiple load conditions onto the vehicle body finite element model, specifically includes the following steps:

[0084] S21: Determine the static stiffness load, dynamic stiffness load, and collision load.

[0085] Among them, static stiffness loads include, but are not limited to, bending stiffness loads and torsional stiffness loads; dynamic stiffness loads include, but are not limited to, the dynamic stiffness loads of key attachment points on the vehicle body; and collision loads include, but are not limited to, frontal collision loads, side collision loads, rear collision loads, and top pressure loads of the vehicle body.

[0086] The static stiffness load is defined as follows:

[0087] The operating condition for the bending stiffness load is a static condition; the bending constraints of the bending stiffness load are: the Z-direction translational degree of freedom of the center of the right front suspension mounting, the Y-direction and Z-direction translational degrees of freedom of the center of the left front suspension mounting, the X-direction and Z-direction translational degrees of freedom of the center of the right rear suspension mounting, and the three-direction translational degrees of freedom of the center of the left rear suspension mounting; the bending stiffness load is a load of 6000N applied vertically downwards to the mounting points of the front and rear seats on the vehicle body.

[0088] The operating condition for the bending stiffness load is a static condition. The bending constraint of the bending stiffness load is: six degrees of freedom of the rear suspension spring fixing seat center. The bending stiffness load is a loading load: applying a pair of equal and opposite vertical forces to the center of the front left and right suspension spring fixing seats on the vehicle body to form a torque of a preset value, where the preset value can be 4000 Nm.

[0089] The dynamic stiffness loads at each key attachment point are defined as follows: the operating condition for the dynamic stiffness loads is the inertial release condition; the loading loads for the dynamic stiffness loads are: unit forces in the x, y, and z directions are applied at each key attachment point.

[0090] The collision load is defined as follows: the collision load is applied under the inertial release condition; the applied load is the critical stage section force determined based on safety strategy, vehicle target requirements, and historical experience data. The critical stage section force includes the first stage average force F1, the second stage average force F2, and the third stage average force F4. Specifically, the first stage average force F1 is applied to the left outer end of the front bumper beam on the vehicle body; the second stage average force F2 is applied at a position offset backward by a preset distance relative to F1 (the left outer end of the front bumper beam), where the preset distance is approximately equal to the front energy absorption space; the third stage average force F3 is applied to the main load inflow points in the passenger compartment area, such as the sill beam, A-pillar, and the front end of the central tunnel. The historical experience data refers to historical data on the relationship between vehicle weight and collision section force, mainly expressing the approximate quantitative relationship between vehicle weight and collision section force. Based on the database relationship curves, the corresponding empirical value of the section force can be directly determined by considering the target vehicle's positioning, type, and level, thus providing critical stage section force input for various collision conditions developed in the early stages. Determining the loading load for collision conditions based on historical experience data ensures the accuracy of the loading load and provides effective guidance for rear vehicle body design.

[0091] In this embodiment, the limitations of static stiffness load, dynamic stiffness load, and collision load are merely illustrative. In other embodiments, the limitations of static stiffness load, dynamic stiffness load, and collision load may be other, which will not be elaborated here.

[0092] S22: Converts dynamic stiffness loads into equivalent static stiffness loads.

[0093] After determining the dynamic stiffness load, the dynamic stiffness load is transformed into an equivalent static stiffness load, thus converting the dynamic load into a static load. This facilitates subsequent iterative solutions and improves the optimization accuracy.

[0094] S23: Convert the collision load into a linear static load.

[0095] After determining the static stiffness load, the static stiffness load is transformed into a linear static load. This transforms the nonlinear dynamic load into a linear static load, facilitating subsequent iterative solutions and improving optimization accuracy.

[0096] S24: Apply the static stiffness load, equivalent static stiffness load, and linear static load to the corresponding positions on the vehicle body finite element model.

[0097] After determining the equivalent static stiffness load corresponding to the static stiffness load, the equivalent static stiffness load corresponding to the dynamic stiffness load, and the linear static load corresponding to the collision load, the static stiffness load, the equivalent static stiffness load, and the linear static load are applied to the corresponding positions of the vehicle body finite element model.

[0098] This embodiment provides a method for determining static stiffness load, dynamic stiffness load, and collision load. Then, the dynamic stiffness load is converted into an equivalent static stiffness load, and the collision load is converted into a linear static load. Finally, the static stiffness load, equivalent static stiffness load, and linear static load are applied to the corresponding positions on the vehicle body finite element model. This clarifies the specific process of applying multiple load conditions to the vehicle body finite element model, converting the dynamic stiffness load into an equivalent static stiffness load, and the collision load into a linear static load. This provides a foundation for obtaining the vehicle body topology optimization analysis model, thereby improving the structural optimization accuracy and reducing the difficulty of load simulation, achieving a balance between efficiency and accuracy in multi-load condition topology optimization.

[0099] In one embodiment, such as Figure 5 As shown, step S30 involves iteratively solving the vehicle body topology optimization analysis model to obtain the target topology optimization result that satisfies the multi-condition quality optimization objective. This specifically includes the following steps:

[0100] S31: Determine the constraints and quality optimization objectives corresponding to the static stiffness condition, dynamic stiffness condition, and collision condition.

[0101] While determining the finite element model of the vehicle body based on the design boundary of the vehicle body, it is necessary to determine the static stiffness condition, dynamic stiffness condition and collision condition loaded onto the finite element model of the vehicle body, and determine the corresponding constraint conditions and quality optimization objectives for the static stiffness condition, dynamic stiffness condition and collision condition.

[0102] S32: Based on the corresponding constraints, iteratively solve the vehicle body topology optimization analysis model to obtain the sub-topology optimization results that satisfy the corresponding working condition quality optimization objectives.

[0103] After obtaining the vehicle body topology optimization analysis model, the model is iteratively solved according to the constraints corresponding to the static stiffness condition, the dynamic stiffness condition, or the collision condition to obtain the sub-topology optimization results that satisfy the quality optimization objectives of the corresponding conditions.

[0104] For example, after determining the constraints and quality optimization objectives corresponding to the static stiffness condition, the vehicle body topology optimization analysis model is iteratively solved to obtain the sub-topology optimization results that satisfy the quality optimization objectives under the static stiffness condition.

[0105] The mathematical model of the optimization problem used in the iterative solution process is... as follows:

[0106] ;

[0107] in, The optimization objective can be various mechanical properties or weight targets, etc. In this embodiment, the optimization objective under each working condition is a quality optimization objective, and the quality optimization objective under each working condition is to minimize the mass. These are design variables, which can be structural, dimensional, or other variables. For each working condition, the design variable is the relative density of each element within the design area, with a discretization value of 0 or 1. When the discretization value is 0, the material at each point forms voids; when the discretization value is 1, the material at each point connects to form a solid. This indicates that optimization makes... The optimization objective is to minimize, such as minimizing weight or flexibility; in this embodiment, it means minimizing mass.

[0108] When performing iterative solutions, optimize the mathematical model of the problem. Subject to:

[0109] ;

[0110] ;

[0111] ;

[0112] in, It is the design response to inequality constraints. It is the design response to the equality constraint. , All of these are design responses that require constraints, such as deformation, stress level, mechanical properties, and volume responses during operation.

[0113] S33: Combine and solve the sub-topology optimization results under static stiffness, dynamic stiffness, and collision conditions to obtain the target topology optimization result that satisfies all quality optimization objectives.

[0114] After obtaining the sub-topology optimization results that satisfy the quality optimization objectives for the corresponding working conditions, the sub-topology optimization results for static stiffness, dynamic stiffness, and collision working conditions are merged and solved to obtain the target topology optimization results for all quality optimization objectives. Specifically, the sub-topology optimization results that simultaneously satisfy the quality optimization objectives for static stiffness, dynamic stiffness, and collision working conditions are taken as the target topology optimization results.

[0115] Among them, the quality optimization objectives corresponding to each working condition can be different or the same. The quality optimization objectives corresponding to each working condition can be to minimize the mass, so as to achieve the purpose of lightweighting to the maximum extent while optimizing the structure.

[0116] In this embodiment, the constraints and quality optimization objectives corresponding to the static stiffness, dynamic stiffness, and collision conditions are determined. Then, based on the corresponding constraints, the vehicle body topology optimization analysis model is iteratively solved to obtain sub-topology optimization results that satisfy the corresponding quality optimization objectives. Finally, the sub-topology optimization results under the static stiffness, dynamic stiffness, and collision conditions are merged and solved to obtain the target topology optimization results for all quality optimization objectives. This refines the steps of iteratively solving the vehicle body topology optimization analysis model to obtain target topology optimization results that satisfy multiple quality optimization objectives. Iterative analysis of each single load condition clarifies the specific path of the target topology optimization result and the correlation between each single load condition. It fully considers the load impact of each condition on the vehicle body, overcomes the problem of unclear load impact on the topology optimization structure in multi-condition optimization, and enables the target topology optimization results to solve all performance issues, ultimately resulting in a more reasonable arrangement of the vehicle body's structural beams.

[0117] In one embodiment, step S31, which involves determining the constraint conditions corresponding to the static stiffness condition, dynamic stiffness condition, and collision condition, specifically includes the following steps:

[0118] S311: Determine the static stiffness threshold and the equivalent static stiffness threshold corresponding to the dynamic stiffness based on the vehicle model requirements.

[0119] The static stiffness thresholds include bending stiffness thresholds and torsional stiffness thresholds, both of which are input thresholds directly determined based on the vehicle model requirements. When applying dynamic stiffness loads to the vehicle body finite element model, the dynamic stiffness loads need to be converted into equivalent static stiffness. Therefore, in subsequent iterations, the constraint threshold for dynamic stiffness is the equivalent static stiffness threshold, where the equivalent static stiffness threshold corresponding to the dynamic stiffness is also a static stiffness threshold determined based on the vehicle model requirements.

[0120] S312: Determine the constraints for the static stiffness condition based on the static stiffness threshold, and determine the constraints for the dynamic stiffness condition based on the equivalent static stiffness threshold.

[0121] After determining the static stiffness threshold and the equivalent static stiffness threshold corresponding to the dynamic stiffness based on the vehicle model requirements, the constraint conditions for the static stiffness condition are determined based on the static stiffness threshold, and the constraint conditions for the dynamic stiffness condition are determined based on the equivalent static stiffness threshold.

[0122] The constraint condition for determining the bending stiffness condition based on the bending stiffness threshold is: the bending stiffness is less than or equal to the bending stiffness threshold. The bending stiffness of the corresponding structure is calculated using the following formula:

[0123] ;

[0124] in, This refers to bending stiffness, expressed in N / m. The load is the bending stiffness condition load, i.e., the force applied to a position such as a seat, and the unit is N; This represents the average value of the maximum displacement of the corresponding structure in a certain direction (e.g., Z-direction upward of the left and right sill beams) under bending stiffness load conditions, in meters.

[0125] The constraint condition for determining the torsional stiffness condition based on the torsional stiffness threshold is: the torsional stiffness is less than or equal to the torsional stiffness threshold. The torsional stiffness of the corresponding structure is calculated using the following formula:

[0126] ;

[0127] in, This refers to bending stiffness, expressed in N / m. Torque, measured in N / m; Twist angle; The load is for torsional stiffness conditions, i.e., the force applied to the center of the front tower base, and the unit is N; In torque The relative displacement of the corresponding structure in a certain direction (Z direction of the center of the left and right front towers) under the action, in meters; The distance between the centers of the corresponding structures (left and right front tower bases) is expressed in meters (m).

[0128] The constraint condition for determining the dynamic stiffness working condition based on the equivalent static stiffness threshold is: the equivalent static stiffness of each critical attachment point is less than or equal to the equivalent static stiffness threshold. The equivalent static stiffness of each critical attachment point is obtained by converting the dynamic stiffness of each critical attachment point into equivalent static stiffness. The equivalent static stiffness of each critical attachment point is calculated using the following formula:

[0129]

[0130] In the formula: The equivalent static stiffness of a key attachment point in a certain direction; The output flexibility is calculated based on the equivalent static stiffness of a key attachment point in a certain direction.

[0131] S313: After transforming the collision condition into a linear static condition, it is loaded onto the vehicle body finite element model to obtain a linearized finite element compliance analysis model of the linear static condition.

[0132] Since the collision performance target of the vehicle body is not defined by the stiffness of the structure, it is not possible to directly determine the collision performance threshold based on the vehicle model requirements as a constraint condition for the collision condition. It is necessary to transform the collision condition into a linear static condition, and then use the specific flexibility target value under each linear static condition as the constraint condition for the collision condition.

[0133] This involves transforming the collision condition into a linear static condition, and then loading the linear static condition onto the vehicle body finite element model to obtain a linearized finite element compliance analysis model of the linear static condition.

[0134] S314: Iteratively solve the linearized finite element compliance analysis model to obtain the compliance target value that meets the requirements.

[0135] After obtaining the linearized finite element compliance analysis model for the linear static working condition, the linearized finite element compliance analysis model is iteratively solved to obtain the compliance target value that meets the requirements, thereby obtaining the corresponding compliance target value under each collision working condition.

[0136] In the iterative solution of the linearized finite element compliance analysis model, it is necessary to define the optimization problem, and then determine the design variables, constraints, and optimization objectives. The constraints include ensuring that the structural volume fraction is less than or equal to a preset percentage (which can be 5%). Then, based on the design variables, constraints, and optimization objectives, the linearized finite element compliance analysis model is iteratively solved to satisfy the compliance target value of the optimization objective.

[0137] In determining the compliance target value for each collision condition, the design variable is the relative density of each element within the structural design space, discretized to either 0 or 1. A value of 0 indicates that the material at each point forms a void; a value of 1 indicates that the material at each point connects to form a solid. The optimization objective for the compliance target value under each collision condition is to minimize the compliance. The constraints under each collision condition can all be volume fraction constraints of less than or equal to 5%.

[0138] It is important to understand that, in order to achieve maximum performance (maximum stiffness performance, i.e., minimum flexibility) based on minimum structural weight cost (the smaller the volume occupied by the design area), the volume fraction can be used as the global response. The volume fraction represents the fraction of the vehicle body's topology optimization result relative to the initial design data. In this embodiment, through detailed comparative analysis of volume fraction components with different percentages, it was determined that when the volume fraction is less than or equal to 5%, the force transmission path is clearer and has a better optimization effect.

[0139] S315: Determine the constraints for the collision condition based on the compliance target value.

[0140] After obtaining the corresponding compliance target values ​​for each collision condition, the constraint conditions for each collision condition are determined based on these values. Specifically, the constraint condition for each collision condition is that the compliance value under that collision condition is less than or equal to the corresponding compliance target value.

[0141] For example, collision scenarios include frontal collision, side collision, rear impact feedback, and roof pressure scenarios. The compliance target value for the frontal collision is d, for the side collision is e, for the rear collision is f, and for the roof pressure is g. The bending stiffness threshold is a, the torsional stiffness threshold is b, and the dynamic stiffness threshold for each key attachment point is c (which can also be the equivalent static stiffness). The mass optimization objective for all scenarios is to minimize mass. The constraints and mass optimization objectives for each scenario are shown in Table 1.

[0142] Table 1

[0143]

[0144] In this embodiment, the static stiffness threshold and the equivalent static stiffness threshold corresponding to the dynamic stiffness are first determined according to the vehicle model requirements. Then, the constraints of the static stiffness condition are determined based on the static stiffness threshold, and the constraints of the dynamic stiffness condition are determined based on the equivalent static stiffness threshold. The collision condition is then transformed into a linear static condition and loaded onto the vehicle body finite element model to obtain a linearized finite element compliance analysis model of the linear static condition. The linearized finite element compliance analysis model is then iteratively solved to obtain the compliance target value that meets the requirements. Finally, the constraints of the collision condition are determined based on the compliance target value. This clarifies the specific process of determining the constraints corresponding to the static stiffness condition, dynamic stiffness condition, and collision condition, providing a foundation for subsequent solution of the target topology optimization results.

[0145] In one embodiment, step S40, which involves parsing the load transfer path of the vehicle body based on the target topology optimization results to obtain the target load transfer path of the vehicle body, specifically includes the following steps:

[0146] S41: Based on the target topology optimization results, determine whether the material variable values ​​of the vehicle body material are less than the preset material variable threshold.

[0147] S42: If the material variable value of the vehicle body material is greater than or equal to the preset material variable threshold, then retain the vehicle body material.

[0148] S43: Based on the distribution of the retained body materials, determine the optimal load transfer path of the body as the target load transfer path.

[0149] After obtaining the target topology optimization results, it is determined whether the material variable values ​​of the vehicle body material are less than the preset material variable threshold. If the material variable values ​​of the vehicle body material are greater than or equal to the preset material variable threshold, it means that the existing material processing technology can meet the requirements of the vehicle body material at this time, so the vehicle body material is retained. Then, based on the distribution state of the retained vehicle body material, the optimal load transfer path of the vehicle body is determined as the target load transfer path. If the material variable values ​​of the vehicle body material are less than or equal to the preset material variable threshold, it means that the existing material processing technology cannot meet the requirements of the vehicle body material at this time, so the vehicle body material with values ​​less than the preset material variable threshold is removed.

[0150] After obtaining the target topology optimization result, the optimal load transfer path of the target topology optimization result component is analyzed, and the analytical scheme is as follows: Figures 6 to 9 As shown. Among them, Figure 6 This is a schematic diagram of the topology optimization results for the longitudinal beams of the vehicle body. Figure 7 According to Figure 6 The schematic diagram of the longitudinal beam structure obtained from the analysis of the longitudinal beam topology optimization results. Figure 6 and Figure 7 The structure within the rectangular frame is the longitudinal beam; Figure 8This is a schematic diagram showing the topology optimization results of the vehicle body's crossbeams. Figure 9 According to Figure 8 The schematic diagram of the beam structure obtained from the analysis of the beam topology optimization results. Figure 8 and Figure 9 The structure within the rectangular frame is the beam.

[0151] In this embodiment, the material variable value of the vehicle body material is first determined based on the target topology optimization result to see if it is less than a preset material variable threshold. If the material variable value of the vehicle body material is greater than or equal to the preset material variable threshold, the vehicle body material is retained. Then, based on the distribution state of the retained vehicle body material, the optimal load transfer path of the vehicle body is determined as the target load transfer path. This clarifies the process of analyzing the load transfer path of the vehicle body based on the target topology optimization result to obtain the target load transfer path of the vehicle body. This effectively eliminates the dependence on and limitations of human experience, thereby enabling the load transfer path of the vehicle body to more accurately and comprehensively meet the design requirements, so as to achieve intelligent optimization of the solution.

[0152] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0153] In one embodiment, a vehicle body design apparatus based on multi-condition topology optimization is provided, which corresponds one-to-one with the vehicle body design method based on multi-condition topology optimization in the above embodiments. For example... Figure 10 As shown, the vehicle body design device based on multi-condition topology optimization includes a first determination module 101, a second determination module 102, an iteration module 103, and a third determination module 104. Detailed descriptions of each functional module are as follows:

[0154] The first determining module 101 is used to determine the finite element model of the vehicle body based on the design boundaries of the vehicle body.

[0155] The second determining module 102 is used to load multiple working condition loads onto the vehicle body finite element model to obtain the vehicle body topology optimization analysis model. The multiple working condition loads include static stiffness working condition loads, dynamic stiffness working condition loads and collision working condition loads.

[0156] The iteration module 103 is used to iteratively solve the vehicle topology optimization analysis model to obtain the target topology optimization result that satisfies the multi-condition quality optimization objective.

[0157] The third determining module 104 is used to analyze the load transfer path of the vehicle body according to the target topology optimization results, obtain the target load transfer path of the vehicle body, and determine the vehicle body frame model according to the target load transfer path.

[0158] Furthermore, the iteration module 103 is specifically used for:

[0159] Determine the constraints and quality optimization objectives corresponding to the static stiffness condition, dynamic stiffness condition, and collision condition;

[0160] Based on the corresponding constraints, the vehicle body topology optimization analysis model is iteratively solved to obtain sub-topology optimization results that satisfy the corresponding working condition quality optimization objectives;

[0161] The sub-topology optimization results under static stiffness, dynamic stiffness, and collision conditions are combined and solved to obtain the target topology optimization results for all quality optimization objectives.

[0162] Furthermore, the iteration module 103 is specifically used for:

[0163] The static stiffness threshold and the equivalent static stiffness threshold corresponding to the dynamic stiffness are determined based on the vehicle model requirements.

[0164] The constraints for the static stiffness condition are determined based on the static stiffness threshold, and the constraints for the dynamic stiffness condition are determined based on the equivalent static stiffness threshold.

[0165] After the collision condition is transformed into a linear static condition, it is loaded onto the vehicle body finite element model to obtain a linearized finite element compliance analysis model of the linear static condition.

[0166] The linearized finite element compliance analysis model is iteratively solved to obtain the compliance target value that meets the requirements;

[0167] The constraints for the collision conditions are determined based on the compliance target value.

[0168] Furthermore, the third determining module 104 is specifically used for:

[0169] Based on the target topology optimization results, determine whether the material variable values ​​of the vehicle body material are less than the preset material variable threshold;

[0170] If the material variable value of the vehicle body material is greater than or equal to the preset material variable threshold, then the vehicle body material is retained;

[0171] Based on the distribution of the retained body materials, the optimal load transfer path of the body is determined as the target load transfer path.

[0172] Furthermore, the second determining module 102 is specifically used for:

[0173] Determine the static stiffness load, dynamic stiffness load, and collision load;

[0174] Convert the dynamic stiffness load into an equivalent static stiffness load.

[0175] Transform the collision load into a linear static load;

[0176] The static stiffness load, equivalent static stiffness load, and linear static load are applied to the corresponding positions on the vehicle body finite element model.

[0177] Furthermore, the first determining module 101 is specifically used for:

[0178] The design boundaries of the vehicle body are determined based on its shape, engineering constraints, surrounding layout conditions, and vehicle requirements.

[0179] The envelope geometry model of the vehicle body is determined based on the design boundary of the vehicle body. The envelope geometry model includes the design area and the design reserved area of ​​the vehicle body. The design reserved area is the reserved space of the vehicle body determined according to the manufacturing process constraints of the vehicle body.

[0180] Finite element meshing is performed on the envelope geometry model of the vehicle body to obtain the finite element model of the vehicle body.

[0181] Specific limitations regarding the vehicle body design device based on multi-condition topology optimization can be found in the limitations of the vehicle body design method based on multi-condition topology optimization mentioned above, and will not be repeated here. Each module in the aforementioned vehicle body design device based on multi-condition topology optimization can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in or independent of the processor in a computer device in hardware form, or stored in the memory of a computer device in software form, so that the processor can call and execute the operations corresponding to each module.

[0182] In one embodiment, a vehicle body design apparatus based on multi-condition topology optimization is provided, which can be a server. The apparatus includes a processor, memory, network interface, and database connected via a system bus. The processor provides computational and control capabilities. The memory includes a non-volatile storage medium and internal memory. The non-volatile storage medium stores an operating system, computer programs, and a database. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage medium. The database stores vehicle body finite element models, vehicle body topology optimization analysis models, and other models, as well as loads, constraints, and optimization objectives for each operating condition. The network interface communicates with external terminal devices via a network connection. When the computer program is executed by the processor, it implements a vehicle body design method based on multi-condition topology optimization.

[0183] In one embodiment, such as Figure 11As shown, a vehicle body design device based on multi-condition topology optimization is provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the steps of the above-mentioned vehicle body design method based on multi-condition topology optimization.

[0184] In one embodiment, a readable storage medium is provided on which a computer program is stored, which, when executed by a processor, implements the steps of the above-described vehicle body design method based on multi-condition topology optimization.

[0185] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium. When executed, the computer program can include the processes of the embodiments of the above methods. Any references to memory, storage, databases, or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory may include random access memory (RAM) or external cache memory.

[0186] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is used as an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above.

[0187] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A vehicle body design method based on multi-condition topology optimization, characterized in that, The method comprises the following steps: determining a body finite element model according to a design boundary of a vehicle body; loading multiple working condition loads on the body finite element model to obtain a body topology optimization analysis model, wherein the multiple working condition loads comprise static stiffness working condition loads, dynamic stiffness working condition loads and collision working condition loads; iteratively solving the body topology optimization analysis model to obtain a target topology optimization result meeting multiple working condition mass optimization objectives; performing load transfer path analysis on the vehicle body according to the target topology optimization result to obtain a target load transfer path of the vehicle body, and determining a body frame model according to the target load transfer path; the iteratively solving the body topology optimization analysis model to obtain a target topology optimization result meeting multiple working condition mass optimization objectives comprises: determining constraint conditions and mass optimization objectives corresponding to static stiffness working conditions, dynamic stiffness working conditions and collision working conditions; iteratively solving the body topology optimization analysis model according to the corresponding constraint conditions to obtain a sub-topology optimization result meeting a corresponding working condition mass optimization objective; combining and solving the sub-topology optimization results under the static stiffness working conditions, the dynamic stiffness working conditions and the collision working conditions to obtain a target topology optimization result of all mass optimization objectives, specifically, taking the sub-topology optimization result meeting the mass optimization objective under the static stiffness working conditions, the sub-topology optimization result meeting the mass optimization objective under the dynamic stiffness working conditions and the sub-topology optimization result meeting the mass optimization objective under the collision working conditions as the target topology optimization result.

2. The method for vehicle body design based on multi-condition topology optimization according to claim 1, characterized in that, the determining constraint conditions corresponding to the static stiffness working conditions, the dynamic stiffness working conditions and the collision working conditions comprises: determining a static stiffness threshold and an equivalent static stiffness threshold corresponding to a dynamic stiffness according to vehicle model requirements of the vehicle body; determining constraint conditions of the static stiffness working conditions according to the static stiffness threshold, and determining constraint conditions of the dynamic stiffness working conditions according to the equivalent static stiffness threshold; loading a linear static working condition obtained by converting the collision working condition on the body finite element model to obtain a linearized finite element flexibility analysis model of the linear static working condition; iteratively solving the linearized finite element flexibility analysis model to obtain a flexibility target value meeting requirements; determining constraint conditions of the collision working condition according to the flexibility target value.

3. The method for vehicle body design based on multi-configuration topology optimization according to claim 1, wherein, the performing load transfer path analysis on the vehicle body according to the target topology optimization result to obtain a target load transfer path of the vehicle body comprises: determining whether a material variable value of a vehicle body material is less than a preset material variable threshold according to the target topology optimization result; if the material variable value of the vehicle body material is greater than or equal to the preset material variable threshold, the vehicle body material is retained; determining an optimal load transfer path of the vehicle body according to a distribution state of the retained vehicle body material as the target load transfer path.

4. The method for vehicle body design based on multi- condition topology optimization according to claim 1, wherein, the loading multiple working condition loads on the body finite element model comprises: determining the static stiffness working condition loads, the dynamic stiffness working condition loads and the collision working condition loads; converting the dynamic stiffness working condition loads into equivalent static stiffness working condition loads; converting the collision working condition loads into linear static working condition loads; Load the static stiffness working condition load, equivalent static stiffness working condition load and linear static working condition load to corresponding positions of the body finite element model.

5. The method for vehicle body design based on multi- condition topology optimization according to claim 1, wherein, The method comprises the following steps: According to the design boundary of the body, a body finite element model is determined. According to the design boundary of the body, an envelope geometry model of the body is determined, the envelope geometry model comprising a design region and a design reserved region of the body, the design reserved region being a reserved space of the body determined according to process manufacturing constraints. The envelope geometry model of the body is subjected to finite element meshing to obtain the body finite element model.

6. The method for vehicle body design based on multi-condition topology optimization according to any one of claims 1-5, characterized in that, The static stiffness working condition load comprises bending stiffness working condition load and torsional stiffness working condition load of the body, the crash working condition load comprises front crash load, side crash load, rear crash load and roof pressure load of the body, and the dynamic stiffness working condition load comprises dynamic stiffness working condition load of all key attachment points of the body.

7. A vehicle body design device based on multi-condition topology optimization, characterized by, The method comprises the following steps: A first determining module is configured to determine a body finite element model according to a design boundary of the body. A second determining module is configured to load multiple working condition loads to the body finite element model to obtain a body topology optimization analysis model, the multiple working condition loads comprising static stiffness working condition load, dynamic stiffness working condition load and crash working condition load. An iteration module is configured to iteratively solve the body topology optimization analysis model to obtain a target topology optimization result meeting multiple working condition mass optimization objectives. A third determining module is configured to analyze a load transmission path of the body according to the target topology optimization result to obtain a target load transmission path of the body, and determine a body frame model according to the target load transmission path. The method comprises the following steps: Determine constraint conditions and mass optimization objectives corresponding to static stiffness working condition, dynamic stiffness working condition and crash working condition. Iteratively solve the body topology optimization analysis model according to the corresponding constraint conditions to obtain a sub-topology optimization result meeting corresponding working condition mass optimization objectives. Combine and solve the sub-topology optimization results under static stiffness working condition, dynamic stiffness working condition and crash working condition to obtain a target topology optimization result of all mass optimization objectives, specifically, the sub-topology optimization result meeting the mass optimization objective under static stiffness working condition, the sub-topology optimization result meeting the mass optimization objective under dynamic stiffness working condition and the sub-topology optimization result meeting the mass optimization objective under crash working condition are taken as the target topology optimization result.

8. A vehicle body design device based on multi-condition topology optimization, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, The processor executes the computer program to implement the steps of the body design method based on multi-working condition topology optimization according to any one of claims 1 to 6.

9. A readable storage medium, the readable storage medium storing a computer program, characterized in that, The computer program is executed by the processor to implement the steps of the body design method based on multi-working condition topology optimization according to any one of claims 1 to 6.

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