A method and system for optimizing vehicle body frame structure

Abstract

This invention provides a method and system for optimizing a vehicle body frame structure. The method includes: establishing a mathematical model for topology optimization of a continuum structure based on SIMP theory; defining a single-condition topology optimization model; setting single-objective topology optimization constraints; obtaining mass-compliance data for each condition through batch single-objective topology optimization; plotting relationship curves based on the mass-compliance data and fitting a mass-compliance function; calculating the second partial derivative of the mass-compliance function to obtain the volume fraction and compliance corresponding to the extreme value of the mass-compliance function when the second partial derivative is zero; performing multi-objective topology optimization analysis based on the compliance values ​​corresponding to the extreme values ​​of each condition; identifying critical paths by combining the force transmission paths of the topology-optimized structure; and optimizing the vehicle body frame structure based on the critical paths. This approach not only ensures that all performance aspects in multi-objective optimization reach optimal design but also reduces the difficulty of multi-objective optimization applications for body-in-white frames, effectively improving the efficiency of multi-objective topology optimization.

Description

Technical Field

[0001] This invention belongs to the field of vehicle body frame design, and particularly relates to a method and system for optimizing vehicle body frame structure. Background Technology

[0002] A reasonable vehicle body frame structure is an important indicator of vehicle performance. To achieve the optimal design of the vehicle body frame structure, topology optimization is generally used in the early stages of vehicle development to find the optimal load transfer path and frame, and the corresponding structure is arranged and designed in the design phase.

[0003] In engineering, the most common topology optimization problem involves using multiple stiffness conditions in statics and low-order natural frequencies in dynamics as optimization objectives. In China, Fan Wenjie et al. proposed using the volume fraction and modal characteristics of the design space as constraints, employing a weighted compromise programming method to study the topology optimization problem of bus frame structures under multiple working conditions, deriving a reasonable frame topology. Fu Yuanfang et al. proposed using the maximization of weighted stiffness of the body under multiple working conditions as the optimization objective, transforming the multi-objective optimization problem into a single-objective optimization problem using a linear weighting method. Wang Guochun et al., combining the concept of equivalent static loads, proposed a body-in-white force transmission path planning method based on asymptotic space topology optimization technology and incorporating an expert system. Under static single working conditions, the relative density of structural elements is often used as the design variable, the volume fraction as the constraint, and the minimization of structural flexibility (i.e., maximization of stiffness) as the objective function. A mathematical model for topology optimization of a continuum structure based on SIMP theory is established, and the objective function for topology optimization under static multi-working conditions is obtained by combining programming methods with the efficacy function method. In multi-objective topology optimization processes, different weight values ​​are often directly assigned to different sub-objectives in the objective function, or the working conditions are layered according to their importance, design space differences, etc., and different weight values ​​are assigned according to different layers.

[0004] However, in multi-objective topology optimization of structures, the overall objective optimization result is adjusted by allocating weight ratios among the sub-objectives in the planning and design objective function. The weight values ​​are directly set based on experience and lack scientific basis or data support. There is also a lack of research on the calculation of weight values ​​in multi-objective optimization, which makes it difficult to achieve ideal results in the design of the vehicle frame structure. Summary of the Invention

[0005] In view of this, embodiments of the present invention provide a method and system for optimizing a vehicle body frame structure, which solves the problem that the weights of sub-objectives in multi-objective optimization are set manually, making it difficult to achieve the optimal effect in the design of the vehicle body frame structure.

[0006] In a first aspect of the present invention, a method for optimizing a vehicle body frame structure is provided, comprising:

[0007] A mathematical model for topology optimization of continuum structures based on SIMP theory is defined, and a single-condition topology optimization model is defined.

[0008] Set single-objective topology optimization constraints, and obtain quality-compliance data for each working condition through batch single-objective topology optimization;

[0009] The relationship curve is plotted based on the mass-compliance data, and the mass-compliance function is fitted. The second partial derivative of the mass-compliance function is calculated to obtain the volume fraction and compliance corresponding to the extremum of the mass-compliance function when the second partial derivative is zero.

[0010] Based on the flexibility values ​​corresponding to the extreme values ​​of each working condition, multi-objective topology optimization analysis is performed. Combined with the force transmission path of the topology optimization structure, the critical path is identified, and the vehicle frame structure is optimized based on the critical path.

[0011] In a second aspect of the present invention, a vehicle frame structure optimization system is provided, comprising:

[0012] The model building module is used to define a mathematical model for topology optimization of continuum structures based on SIMP theory, and to define a single-condition topology optimization model.

[0013] The single-objective optimization module is used to set single-objective topology optimization constraints and obtain quality-compliance data for each working condition through batch single-objective topology optimization.

[0014] The extreme value acquisition module is used to draw a relationship curve based on mass-compliance data, fit a mass-compliance function, calculate the second partial derivative of the mass-compliance function, and obtain the volume fraction and compliance corresponding to the extreme value of the mass-compliance function when the second partial derivative is zero.

[0015] The multi-objective optimization module is used to perform multi-objective topology optimization analysis based on the compliance value corresponding to the extreme values ​​of each working condition, combine the topology optimization structure force transmission path, identify the critical path, and optimize the vehicle frame structure based on the critical path.

[0016] In a third aspect of the present invention, an electronic device is provided, including a memory, a processor, and a computer program stored in the memory and executable by the processor, wherein the processor executes the computer program to implement the steps of the method as described in the first aspect of the present invention.

[0017] In a fourth aspect of the present invention, a computer-readable storage medium is provided, the computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the method provided in the first aspect of the present invention.

[0018] In this embodiment of the invention, the problem of setting empirical weights in optimization is transformed into a mathematical problem. By solving the extreme value of the partial derivative of the structural compliance-volume fraction function for each working condition, the inflection point of the function is obtained. The structural compliance calculated from the inflection point is used to define the multi-objective optimization constraint function. This not only forces the compliance after optimization for each working condition to be no less than the compliance value at the inflection point, ensuring that all performance in multi-objective optimization reaches the optimal design, but also reduces the difficulty of applying multi-objective optimization to the body-in-white frame, avoids excessive reliance on human experience, and improves the efficiency of multi-objective topology optimization. At the same time, it can more clearly obtain the force transmission path in the topology optimization result and more accurately identify the critical path, ensuring that the body frame structure achieves the most ideal design result. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art 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.

[0020] Figure 1 This is a schematic flowchart of a vehicle body frame structure optimization method according to an embodiment of the present invention;

[0021] Figure 2 This is a schematic diagram of the quality-compliance relationship curves under various working conditions provided in one embodiment of the present invention;

[0022] Figure 3 This is a schematic diagram of a vehicle frame structure optimization system provided in one embodiment of the present invention;

[0023] Figure 4 This is a schematic diagram of the structure of an electronic device provided in one embodiment of the present invention. Detailed Implementation

[0024] To make the objectives, features, and advantages of this invention more apparent and understandable, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described below are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0025] It should be understood that, when used in this specification and the appended claims, the term "comprising" indicates the storage of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0026] The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0027] It should be understood that the terms "comprising" and other similar expressions in the specification, claims, and accompanying drawings of this invention are intended to cover a non-exclusive inclusion, such as a process, method, system, or apparatus that includes a series of steps or units and is not limited to the listed steps or units. Furthermore, "first" and "second" are used to distinguish different objects and are not intended to describe a specific order.

[0028] It should be noted that in the application of multidisciplinary topology optimization, the traditional method of allocating and adjusting the overall target optimization result by setting the weight ratio between sub-objectives based on experience has the following problems: First, the difference in the setting of the weight values ​​of sub-conditions may lead to drastically different optimization results, and there is also a certain amount of trial and error in adjusting the weight values; Second, the weight values ​​are highly dependent on engineering experience, and it is necessary to identify the needs and impacts of the optimization condition on the structure (different weights will lead to different engineering design focuses); Third, even skilled engineers need to debug the weight values ​​of each sub-condition multiple times based on the experience model in the optimization setting process to obtain a relatively ideal optimization result, which is actually inefficient.

[0029] Please see Figure 1 A flowchart illustrating a method for optimizing a vehicle body frame structure provided in this embodiment of the invention includes:

[0030] S101. Mathematical model for topology optimization of continuum structures based on SIMP theory, defining a single-condition topology optimization model;

[0031] The mathematical model for topology optimization of continuum structures based on SIMP (Solid Isotropic Material with Penalization) theory defines a single-condition topology optimization model as follows:

[0032] findρ = [ρ1 ρ2 ρ3 ... ρ n ] T

[0033]

[0034] stKU=F

[0035]

[0036] 0<ρ min <<ρ i <<1;

[0037] In the formula, ρ i Let C be the relative density of the structural elements, C be the overall flexibility of the structure, U be the displacement matrix, P be the penalty factor, K be the total stiffness matrix of the structure before optimization, and F be the force column vector. i Let K0 be the column vector of element displacements, V be the initial element stiffness matrix, V be the optimized total volume of the structure, V0 be the initial total volume of the structure, and α be the volume fraction (retained element volume / total volume of the structure). i For the optimized element volume, ρ min This is the lower bound for the design variables, and its purpose is to prevent singularity in the element stiffness matrix.

[0038] Among them, the performance targets involved in each working condition are defined in an engineering manner, the performance quantitative characterization values ​​are set, and the boundary conditions of the target working conditions are defined.

[0039] Vehicle performance engineering quantification is at least divided into NVH (Noise, Vibration, and Harshness) conditions, collision conditions, and strength conditions. NVH conditions include body bending stiffness, torsional stiffness, and tailgate torsional stiffness. Collision conditions include intrusion volume, peak acceleration, and energy absorption ratio related to 100% frontal collision, frontal offset collision, side collision, rear-end collision, and roof crush. Strength conditions include element and nodal stress and strain related to single-sided upward bounce, torsion, and ditch driving. Boundary conditions include constraints, forces, and torques.

[0040] S102. Set single-objective topology optimization constraints and obtain the quality-compliance data for each working condition through batch single-objective topology optimization.

[0041] For topology optimization under a single objective condition, it is necessary to define the topology optimization space, including the objective function, constraint function, engineering constraints, etc.

[0042] Specifically, for single-objective topology optimization, the constraint function is defined as the mass fraction of the design space, and the objective function is defined as the total structural compliance under a single load case. The mass fraction can range from 1% to 20%, and the increment step is Δ = 1%.

[0043] For each working condition, the total structural flexibility was tested under different volume fractions to obtain the mass-flexibility big data for each working condition.

[0044] S103. Plot the relationship curve based on the mass-compliance data, fit the mass-compliance function, calculate the second partial derivative of the mass-compliance function, and obtain the volume fraction and compliance corresponding to the extreme value of the mass-compliance function when the second partial derivative is zero.

[0045] Construct a planar coordinate system to represent the quality-compliance data using coordinate points. Plot the relationship curves for each working condition based on the coordinate points corresponding to the same working condition. The relationship curves for each working condition are shown below. Figure 2 As shown.

[0046] Mathematical methods such as polynomials, logarithms, linear equations, or moving averages are used to fit the relationship curves to obtain the quality compliance function for each working condition.

[0047] For the fitted mass-compliance function, take the second-order partial derivative, and when the second-order partial derivative is equal to zero, obtain the volume fraction and compliance corresponding to the extremum of the mass-compliance function.

[0048] For example, suppose the LC of each operating condition is fitted. j The volume fraction (mass) - structural flexibility (performance) curve is f LCj (V j );

[0049] Then for the fitted function f LCj (V j Find the second partial derivative. And let f” LCj =0 yields the mass-compliance function f LCj (V j The volume fraction corresponding to the extreme value is V. j V j The corresponding structural flexibility is C. j-inflection .

[0050] S104. Based on the flexibility values ​​corresponding to the extreme values ​​of each working condition, perform multi-objective topology optimization analysis, combine the topology optimization structure force transmission path, identify the critical path, and optimize the vehicle frame structure based on the critical path.

[0051] Through multi-objective topology optimization analysis, a clear structural force transmission path can be obtained. Based on all the topological force transmission paths, the critical path can be identified. In some embodiments, the obtained critical path can be iteratively verified using topology optimization to ensure the reliability and accuracy of the optimized structure.

[0052] The multi-objective topology optimization model for the body-in-white is as follows:

[0053] find V opt ={V1 V2 ... V n}

[0054] min V or Mass

[0055] stC j ≥C j-inflection

[0056] KU = F

[0057] V opt / V0≤P;

[0058] Among them, Vopt To optimize the volume of the designed space, C j Let U be the total structural flexibility for each working condition, U be the displacement matrix, K be the total structural stiffness matrix before optimization, and P be the penalty factor (P≤0.3).

[0059] Preferably, in the multi-objective topology optimization analysis of the body-in-white, the objective function is set to minimize volume or mass, the constraint function is that the compliance of each operating condition is not less than the compliance value corresponding to the extreme value of the operating condition, and the volume fraction is set to not exceed a predetermined value. For example, the constraint function is that the compliance of each operating condition is not less than the mass-compliance function. The total structural flexibility C corresponding to the inflection point of the function j-inflection The volume fraction constraint is usually set to no more than 0.3.

[0060] Preferably, the predetermined performance in the vehicle's operating conditions is verified, the body frame structure design is adjusted based on the feedback of the predetermined vehicle performance, and iterative verification is carried out.

[0061] In this embodiment, compared to the prior art:

[0062] First, it can avoid the problems caused by adjusting the overall target optimization results based on the weight ratio allocation between sub-objectives set by experience. It transforms the problem of setting the experience in optimization into a mathematical problem. By solving the extreme value of the partial derivative of the sub-condition structural compliance-volume fraction function, the inflection point of the function is obtained. The structural compliance obtained by inversely using the inflection point is used to define the multi-objective optimization constraint function, which reduces the difficulty of multi-objective optimization application.

[0063] Second, it can achieve optimal design for all performance aspects in multi-objective optimization. Conventional methods essentially assign different weights to different performance objectives based on their importance, and can only approach the optimal design of each objective through iteration based on the weight theory, but cannot achieve the optimal design for all objectives. This embodiment achieves optimal design for all performance aspects in multi-objective optimization by designing compliance related to different performance aspects and forcibly constraining each working condition in the optimization process to ensure that the compliance after optimization is not less than the compliance value of the inflection point of the quality-performance curve.

[0064] Third, the force transmission path is clearer in the topology results obtained compared to conventional methods, making it easier to identify the critical path during the result analysis stage and facilitating the interpretation and design of detailed structural schemes.

[0065] Fourth, it can improve the efficiency of multi-objective optimization, reducing the optimization time required for the same vehicle body or structure. When performance fails to meet expectations during the structural verification stage, conventional methods require simultaneous analysis and verification of the potential impacts of the multi-objective optimization weight setting and path analysis steps (both individual and cross-influences need to be evaluated), necessitating multiple iterations to complete the final structural design. The method in this embodiment, however, avoids subjective influencing factors during the multi-objective optimization setting stage, and can complete the final structural design simply by analyzing and verifying the differences between different analytical schemes, thus avoiding the increased time costs caused by the cross-influence between different process steps.

[0066] In one embodiment, the actual body-in-white frame structure design process is as follows:

[0067] Step 1: Topology space modeling. In engineering applications, various commercial software can be used to build topology spaces, such as the control blocks function of DEP meshworks software, the shrink wrap function of Hypermesh software, and further processing of the cavity model built by SFE concept software into an applicable 3D topology model, etc.

[0068] Step 2: Defining the working condition. Based on the actual performance evaluation items of the enterprise, you can define industry-wide common or enterprise-specific analysis working conditions. Taking the bending stiffness working condition definition of the body-in-white as an example, you need to define the loading force F (a negative Z-axis force of 1000N is applied to the front and middle row seats respectively), and define the degree of freedom constraints (constraining the left front suspension with 23 degrees of freedom, the right front suspension with 3 degrees of freedom, the left rear suspension with 123 degrees of freedom, and the right rear suspension with 13 degrees of freedom respectively).

[0069] Step 3: Define the bending stiffness topology optimization. Various software programs, such as Optistruct, Nastran, and Tosca, can be used to define the topology optimization process. For example, in Hypermesh, defining the bending stiffness topology optimization steps based on Optistruct includes:

[0070] In the analysis > optimization panel

[0071] Create a topology optimization process;

[0072] Establish responses such as overall structural compliance and volume fraction;

[0073] Then set constraint functions for different volume fractions (set volume fraction volumefrac ≤ 10% in dconstraints);

[0074] Set the objective function (in the objective function, set the structural compliance to the minimum, and select the bending stiffness condition defined in the previous step).

[0075] Step 4: After completing the topology optimization calculation based on different volume fraction constraints under bending conditions, the data can be extracted and the compliance-volume fraction curve can be plotted in Excel. The performance-mass curve can be referenced. Figure 2 For the LC2 load case, the compliance-volume fraction fitting function for the bending load case is:

[0076] f(x) = (3E + 0.8)x 5 -(3E+07)x 4 +(5E+07)x 3 -(6E+06)x 2 +388664x-9411.6;

[0077] Step 5: Take the second derivative of f(x), let We can obtain x = 0.06, which, when substituted into f(x), gives f(x) = -525. That is, the total flexibility of the structure at the inflection point of the bending stiffness condition is C1 = 525. Similarly, we can obtain the total flexibility of the structure at the inflection point of the torsional stiffness condition is C2 = 800, and the total flexibility of the structure at the inflection point of the tailgate torsional condition is C3 = 330.

[0078] Step Six: Multi-objective Optimization Working Condition Setting. After the curves for different working conditions are plotted, a multi-objective optimization process can be defined. For example, a topology optimization step based on Optistruct for multiple stiffnesses (bending stiffness, torsional stiffness, and tailgate torsional stiffness) can be defined in Hypermesh.

[0079] In the analysis > optimization panel, create a topology optimization process;

[0080] Establish the overall compliance response of the bending stiffness structure (defined as compliance-bend), the overall compliance response of the torsional stiffness structure (defined as compliance-tor), and the overall compliance response of the tailgate torsional stiffness structure (defined as compliance-reartor). Establish the volume fraction response and define the model mass response (MASS).

[0081] Establish three constraint functions dconstraints for different working conditions: define compliance-bend as not less than 525 (C1 = 525 is the inflection point compliance of the bending stiffness working condition) and associate it with the bending stiffness working condition; define compliance-tor as not less than 800 (C2 = 800 is the inflection point compliance of the torsional stiffness working condition) and associate it with the torsional stiffness working condition; define compliance-reartor as not less than 330 (C3 = 330 is the inflection point compliance of the tailgate torsional stiffness working condition) and associate it with the tailgate torsional stiffness working condition.

[0082] Establish a volume fraction constraint function (set the volume fraction volumefrac ≤ 30% in dconstraints);

[0083] The objective function is defined as minimizing the model quality (min MASS).

[0084] Step 7: Obtain the multidisciplinary topology optimization results that take into account bending stiffness, torsional stiffness, and tailgate torsional stiffness.

[0085] Step 8: Based on the results of multidisciplinary topology optimization, the optimal position of the floor beam can be determined. The model before and after optimization is verified and compared. The bending stiffness is increased by 304 N / mm, the torsional stiffness is increased by 833 N.m / deg, and the tailgate torsional stiffness is increased by 436 N / mm.

[0086] 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.

[0087] Figure 3 A schematic diagram of a vehicle frame structure optimization system provided in an embodiment of the present invention includes:

[0088] Model building module 310 is used for mathematical models of topology optimization of continuum structures based on SIMP theory, and defines a single-condition topology optimization model.

[0089] The single-objective optimization module 320 is used to set single-objective topology optimization constraints and obtain the quality-compliance data of each working condition through batch single-objective topology optimization.

[0090] The constraint function is defined as the mass fraction of the design space, and the objective function is defined as the total structural flexibility under a single load condition.

[0091] Among them, the volume fraction of topology optimization for each single working condition is set within a predetermined range, and the increment step is set to a preset value;

[0092] Extract the total structural compliance of the last iteration of the optimization model that satisfies the convergence condition, and obtain the quality-compliance data within a predetermined interval.

[0093] The extreme value acquisition module 330 is used to draw a relationship curve based on mass-compliance data, fit a mass-compliance function, calculate the second partial derivative of the mass-compliance function, and obtain the volume fraction and compliance corresponding to the extreme value of the mass-compliance function when the second partial derivative is zero.

[0094] The multi-objective optimization module 340 is used to perform multi-objective topology optimization analysis based on the compliance value corresponding to the extreme values ​​of each working condition, combine the topology optimization structure force transmission path, identify the critical path, and optimize the vehicle frame structure based on the critical path.

[0095] In the multi-objective topology optimization analysis of the body-in-white, the objective function is set to minimize the volume or mass, the constraint function is that the compliance of each working condition is not less than the compliance value corresponding to the extreme value of the working condition, and the volume fraction is set not to exceed a predetermined value.

[0096] Preferably, the predetermined performance in the vehicle's operating conditions is verified, and the structural design is adjusted and iteratively verified based on the feedback from the predetermined vehicle performance.

[0097] In this embodiment, the traditional vehicle body topology optimization process is improved by adding the volume fraction (mass)-structural flexibility (performance) curves for each sub-condition in multi-objective optimization. The conventional method of setting condition weights based on experience is changed to setting constraints and objective functions based on objective data. As a result, not only can the structural flexibility obtained by inverse calculation through the inflection point be used to define the constraint function for multi-objective optimization, reducing the difficulty of multi-objective optimization, but also, under the constraint of the flexibility value at the inflection point of the mass-performance curve, it can be ensured that all performances in the multi-objective optimization of the vehicle body can reach the optimal design, and the efficiency of multi-objective optimization can be effectively improved.

[0098] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0099] Those skilled in the art will understand that all or part of the steps in the methods of the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium. When the program is executed, it implements part or all of the processes in steps S101 to S103. The storage medium includes, for example, ROM / RAM.

[0100] In one embodiment, such as Figure 4 As shown, Figure 4 This is a schematic diagram of an electronic device for vehicle frame structure design according to an embodiment of the present invention. The electronic device can be a computer used for multi-objective topology optimization of the body-in-white frame. Figure 4As shown, the electronic device 4 of this embodiment includes at least: a memory 410, a processor 420, and a system bus 430. The memory 410 includes an executable program 4101 stored thereon. As those skilled in the art will understand, Figure 4 The electronic device structure shown does not constitute a limitation on the electronic device and may include more or fewer components than shown, or combine certain components, or have different component arrangements.

[0101] The following is combined Figure 4 A detailed introduction to each component of the electronic device:

[0102] The memory 410 can be used to store software programs and modules. The processor 420 executes various functional applications and data processing of the electronic device by running the software programs and modules stored in the memory 410. The memory 410 may mainly include a program storage area and a data storage area. The program storage area may store the operating system, application programs required for at least one function (such as sound playback function, image playback function, etc.), etc.; the data storage area may store data created according to the use of the electronic device (such as cached data), etc. In addition, the memory 410 may include high-speed random access memory, and may also include non-volatile memory, such as at least one disk storage device, flash memory device, or other volatile solid-state storage device.

[0103] The memory 410 contains an executable program 4101 for network request methods. This executable program 4101 can be divided into one or more modules / units, which are stored in the memory 410 and executed by the processor 420 to perform tasks such as vehicle frame topology optimization. Each module / unit can be a series of computer program instruction segments capable of performing a specific function, describing the execution process of the computer program 4101 in the electronic device 4. For example, the computer program 4101 can be divided into a model building module, a single-objective optimization module, an extreme value acquisition module, and a multi-objective optimization module.

[0104] The processor 420 is the control center of the electronic device. It connects various parts of the electronic device via various interfaces and lines. By running or executing software programs and / or modules stored in the memory 410, and by calling data stored in the memory 410, it performs various functions and processes data, thereby monitoring the overall status of the electronic device. Optionally, the processor 420 may include one or more processing units; preferably, the processor 420 may integrate an application processor and a modem processor, wherein the application processor mainly handles the operating system, application programs, etc., and the modem processor mainly handles wireless communication. It is understood that the modem processor may also not be integrated into the processor 420.

[0105] The system bus 430 is used to connect various functional components inside the computer, transmitting data, address, and control information. Its type can be, for example, a PCI bus, an ISA bus, or a CAN bus. Instructions from the processor 420 are transmitted to the memory 410 via the bus, and the memory 410 sends data back to the processor 420. The system bus 430 is responsible for data and instruction exchange between the processor 420 and the memory 410. Of course, the system bus 430 can also connect to other devices, such as network interfaces and display devices.

[0106] In this embodiment of the invention, the executable program executed by the processing 420 of the electronic device includes:

[0107] A mathematical model for topology optimization of continuum structures based on SIMP theory is defined, and a single-condition topology optimization model is defined.

[0108] Set single-objective topology optimization constraints, and obtain quality-compliance data for each working condition through batch single-objective topology optimization;

[0109] The relationship curve is plotted based on the mass-compliance data, and the mass-compliance function is fitted. The second partial derivative of the mass-compliance function is calculated to obtain the volume fraction and compliance corresponding to the extremum of the mass-compliance function when the second partial derivative is zero.

[0110] Based on the flexibility values ​​corresponding to the extreme values ​​of each working condition, multi-objective topology optimization analysis is performed. Combined with the force transmission path of the topology optimization structure, the critical path is identified, and the vehicle frame structure is optimized based on the critical path.

[0111] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0112] It should be understood that numerous technical details have been described in this specification, and embodiments thereof may be practiced in conjunction with common general knowledge without further details. In some embodiments, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification. Similarly, it can be understood that, in order to streamline the disclosure of this invention and aid in the understanding of one or more of the various aspects of the invention, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof in the above description of exemplary embodiments of the invention. However, this disclosure should not be interpreted as reflecting an intention that the claimed invention requires more features than those expressly recited in each claim. Rather, as reflected in the claims, inventive aspects lie in fewer than all features of a single foregoing disclosed embodiment. Therefore, the claims following the detailed description are hereby expressly incorporated into the detailed description, wherein each claim itself is a separate embodiment of the invention. It should be noted that, without conflict, the embodiments and features in the embodiments of this application may be combined with each other. The invention is not limited to any single aspect, nor to any single embodiment, nor to any combination and / or substitution of these aspects and / or embodiments. Moreover, each aspect and / or embodiment of the invention can be used alone or in combination with one or more other aspects and / or embodiments thereof.

[0113] 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.

Claims

1. A method of optimizing a body frame structure, characterized by, The method comprises the following steps: a mathematical model of continuum structure topology optimization based on SIMP theory is used to define a single working condition topology optimization model; Set single target topology optimization constraints, get the mass of each working condition through batch single target topology optimization Compliance data; based on quality plotting the compliance data and fitting a quality compliance function, for the quality taking a second partial derivative of the compliance function and obtaining the quality at which the second partial derivative is zero the volume fraction and compliance corresponding to the extremum of the compliance function; a multi-objective topology optimization analysis is performed according to the flexibility values corresponding to the working condition inflection points, a key path is identified by combining a force transmission path of the topology optimization structure, and the body frame structure is optimized based on the key path.

2. The method of claim 1, wherein, The setting of the single-objective topology optimization constraint comprises defining a constraint function as a mass fraction of a design space and defining a target function as a total flexibility of the single working condition structure.

3. The method of claim 1, wherein, The setting single-objective topology optimization constraint is used to obtain the mass of each working condition through batch single-objective topology optimization The flexibility data includes: setting the volume fraction of each single-working-condition topology optimization in a predetermined interval, and setting the increment step to a predetermined value; The total flexibility of the last iteration step of the optimization model satisfying the convergence condition is extracted to obtain the mass in the predetermined interval flexibility data.

4. The method of claim 1, wherein, The multi-objective topology optimization analysis according to the flexibility values corresponding to the working condition inflection points comprises setting a target function as a minimum volume or mass and a constraint function as a flexibility not less than the flexibility value corresponding to the working condition inflection point in the multi-objective topology optimization analysis of the body-in-white, and setting a volume fraction not more than a predetermined value.

5. The method of claim 1, wherein, The optimization of the body frame structure based on the key path by combining the force transmission path of the topology optimization structure further comprises verifying a predetermined performance in a vehicle working condition, adjusting the design of the body frame structure based on a feedback of the predetermined performance of the vehicle, and performing iterative verification.

6. A vehicle body frame structure optimization system characterized by comprising: The method comprises the following steps: a mathematical model of continuum structure topology optimization based on SIMP theory is used to define a single working condition topology optimization model; A single-objective optimization module is configured to set a single-objective topology optimization constraint and obtain mass of each working condition through batch single-objective topology optimization Compliance data; an extremum acquisition module configured to acquire the quality based on the quality a flexibility data plotting relationship curve and fitting the quality a flexibility function, the quality a second-order partial derivative of the flexibility function, and acquiring the quality when the second-order partial derivative is zero a volume fraction and a flexibility corresponding to an inflection point of the flexibility function; a multi-objective topology optimization analysis is performed according to the flexibility values corresponding to the working condition inflection points, a key path is identified by combining a force transmission path of the topology optimization structure, and the body frame structure is optimized based on the key path.

7. The system of claim 6, wherein, The setting of the single-objective topology optimization constraint comprises defining a constraint function as a mass fraction of a design space and defining a target function as a total flexibility of the single working condition structure.

8. The system of claim 6, wherein, The multi-objective topology optimization analysis according to the flexibility values corresponding to the working condition inflection points comprises setting a target function as a minimum volume or mass and a constraint function as a flexibility not less than the flexibility value corresponding to the working condition inflection point in the multi-objective topology optimization analysis of the body-in-white, and setting a volume fraction not more than a predetermined value.

9. An electronic device 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 frame structure optimization method according to any one of claims 1 to 5.

10. A computer-readable storage medium storing a computer program, the computer program comprising instructions that, when executed by a computer, cause the computer to perform the method of any one of claims 1 to 9. The computer program is executed to implement the steps of the body frame structure optimization method according to any one of claims 1 to 5.

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