Vehicle body key joint rigidity distribution method and system based on multi-objective optimization
Through multi-objective optimization methods, the stiffness contribution of key joints of the body is scientifically quantified, which solves the problems of weight redundancy and long development cycle in traditional designs, realizes the coordinated optimization of body stiffness and lightweight, and improves design efficiency and manufacturing capabilities.
Patent Information
- Application Number
- CN202510520239.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-24
- Publication Date
- 2025-08-01
AI Technical Summary
The design of traditional body key joints relies on experience and trial and error methods, resulting in weight redundancy and long development cycles. The existing methods ignore the coupling relationship between multiple targets, have low computing efficiency and difficulty in quantifying the weight contribution of joints, resulting in redundancy or insufficient local stiffness, making it difficult to achieve coordinated optimization of body stiffness and lightweight.
The multi-objective optimization method is adopted to scientifically quantify the stiffness contribution metric model, dynamic stiffness allocation game model and multi-scale stiffness collaborative optimization, and the stiffness contribution of each joint is optimized, and the joint design parameters are output, and an executable production plan is output.
It realizes the precise allocation of key joint stiffness of the vehicle body, improves performance, reduces costs, improves design efficiency, meets manufacturing constraints, and supports efficient R&D and manufacturing.
Smart Images
Figure CN120409003A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of optimization allocation, and particularly relates to a method and system for stiffness allocation of key body joints based on multi-objective optimization. Background Art
[0002] The traditional design of key body joints mainly relies on engineers' experience and historical data, and repeatedly adjusts geometric parameters by the trial-and-error method, resulting in weight redundancy and a long development cycle. Existing methods mostly focus on single-objective optimization, such as lightweight or stiffness maximization, ignoring the complex coupling relationships between multiple objectives. For example, excessive weight reduction leads to insufficient local stiffness, while simply increasing stiffness results in a sharp increase in material costs. In addition, the design variables cover multiple dimensions such as geometric shape, material properties, and process parameters. Traditional optimization algorithms have low computational efficiency and the optimization results often violate manufacturing constraints such as stamping forming and welding processes. The existing technology lacks a scientific stiffness allocation mechanism and is difficult to quantify the contribution weights of each joint to the vehicle body stiffness, resulting in coexistence of local stiffness redundancy and insufficiency, and low global stiffness improvement efficiency.
[0003] The above bottlenecks seriously restrict the collaborative optimization of vehicle body stiffness performance, manufacturing cost, and lightweight, and there is an urgent need for a multi-objective stiffness allocation method with high precision and high efficiency. Summary of the Invention
[0004] To solve the above problems existing in the prior art, the present invention proposes a method and system for stiffness allocation of key body joints based on multi-objective optimization.
[0005] The object of the present invention can be achieved by the following technical solutions: A method for stiffness allocation of key body joints based on multi-objective optimization, comprising: S1: Obtain key body joint information, and construct a key body joint data set according to the key body joint information; S2: Process the key body joint data set through a stiffness contribution quantification model to obtain a stiffness allocation weight vector set; S3: Process the stiffness allocation weight vector set through a dynamic stiffness allocation game model to obtain an optimal stiffness increment set; S4: Output a stiffness dynamic allocation result through multi-scale stiffness collaborative optimization of the optimal stiffness increment set, and output a production plan for key body joints according to the stiffness dynamic allocation result.
[0006] Preferably, the process of obtaining the stiffness allocation weight vector set in step S2 is as follows: S201: Construct a stiffness transfer matrix according to the key body joint data set; S202: Perform stiffness priority allocation weight calculation on the stiffness transfer matrix to obtain a stiffness allocation weight vector set.
[0007] Preferably, the mathematical expression of the stiffness transfer matrix in step S201 is: , where K g is the overall stiffness of the vehicle body, k i is the stiffness of the i-th joint, k n is the stiffness of the n-th joint, and α max is the maximum local stress.
[0008] Preferably, the mathematical expression for calculating the stiffness priority allocation weight in step S202 is: , where w i is the stiffness priority allocation weight of the i-th joint, R i is the resource cost consumption of the i-th joint, R max is the maximum resource cost consumption of the joint, ||T(:,i)||2 is the L2 norm of the i-th column of the stiffness transfer matrix, ||T(:,j)||2 is the L2 norm of the j-th column of the stiffness transfer matrix, and n is the number of joints.
[0009] Preferably, the process of obtaining the optimal stiffness increment set in step S3 is as follows: S301: The dynamic stiffness allocation game model receives the stiffness allocation weight vector set and calculates the joint stiffness gain through the stiffness gain function; S302: Maximize the joint stiffness gain through the stiffness improvement strategy to obtain the optimal stiffness increment set.
[0010] Preferably, the mathematical expression of the stiffness gain function in step S301 is: , where ΔV i is the volume increment of the i-th joint, Δk i is the stiffness improvement amount of the i-th joint, Δm i is the manufacturing cost increment of the i-th joint, β is the penalty coefficient, c i is the unit manufacturing cost coefficient of the i-th joint, and P i is the material density of the i-th joint.
[0011] Preferably, the process of multi-scale stiffness collaborative optimization in step S4 is as follows: S401: Preset the joint design parameters; S402: Preset the joint design constraint conditions, and the joint design constraint conditions include vehicle body scale constraint conditions, joint scale constraint conditions, and material scale constraint conditions; S403: Update the joint design parameters through the joint design constraint conditions to obtain joint design update parameters; S404: Verify the joint design update parameters through multi-scale FEA and output the stiffness distribution result.
[0012] Preferably, the mathematical expression of the vehicle body scale constraint condition in step S402 is: , where α i is the position correction factor, K t is the preset target torsional stiffness of the joint design, K g is the overall torsional stiffness of the vehicle body, k i is the stiffness of the i-th joint, and n is the number of joints.
[0013] Preferably, the mathematical expression of the joint scale constraint condition in step S402 is: , where m i is the mass of the i-th joint, m max,i is the maximum allowable mass of the i-th joint, k min,i is the lower limit of the stiffness of the i-th joint, k i is the stiffness of the i-th joint.
[0014] A vehicle body key joint stiffness distribution system based on multi-objective optimization, the system is applied to the above vehicle body key joint stiffness distribution method, including a data set construction module, a stiffness contribution degree quantification module, a dynamic stiffness distribution game module, and a stiffness collaborative optimization distribution module; The data set construction module is used to obtain vehicle body key joint information and construct a vehicle body key joint data set; The stiffness contribution degree quantification module is used to process the vehicle body key joint data set through a stiffness contribution degree quantification model to obtain a stiffness distribution weight vector set; The dynamic stiffness distribution game module is used to process the stiffness distribution weight vector set through a dynamic stiffness distribution game model to obtain an optimal stiffness increment set; The stiffness collaborative optimization distribution module is used to output a stiffness dynamic distribution result through multi-scale stiffness collaboration for the optimal stiffness increment set, and output a vehicle body key joint production plan according to the stiffness dynamic distribution result.
[0015] The beneficial effects of the present invention are: (1) Obtain a stiffness distribution weight vector set through a stiffness contribution degree quantification model, scientifically quantify the stiffness contribution degree of each joint of the vehicle body, realize dynamic adjustment of the stiffness contribution degree weight, preferentially strengthen high-yield-low-consumption joints, and provide a basis for subsequent dynamic vehicle body joint stiffness distribution.
[0016] (2) An optimal stiffness increment set is obtained through a dynamic stiffness allocation game model, a stiffness benefit function is constructed, and a stiffness improvement strategy is designed to obtain an optimal stiffness increment set that conforms to the maximum stiffness benefit, thereby quantifying the "performance-resource" marginal relationship and achieving precise allocation of the stiffness of each joint of the vehicle body.
[0017] (3) The dynamic allocation result of stiffness is output through multi-scale stiffness collaborative optimization, and a production plan for the key joints of the vehicle body is output according to the dynamic allocation result of stiffness. This not only realizes the scientific and precise allocation of the stiffness of the key joints of the vehicle body, but also docks the optimization result of stiffness allocation with the production system, outputs a directly executable production plan for the key joints of the vehicle body, and brings certain improvements in dimensions such as performance, cost, efficiency, and sustainability, providing core support for the efficient research and development and manufacturing of the key joints of the vehicle body. Description of the Drawings
[0018] For the convenience of those skilled in the art to understand, the present invention will be further described below with reference to the accompanying drawings.
[0019] Figure 1 It is a schematic flowchart of a method for allocating the stiffness of key joints of a vehicle body based on multi-objective optimization according to the present invention. Detailed Embodiments
[0020] To further elaborate on the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following will describe in detail the specific embodiments, structures, features, and effects of the present invention with reference to the accompanying drawings and preferred embodiments.
[0021] Please refer to Figure 1 , a method for allocating the stiffness of key joints of a vehicle body based on multi-objective optimization, includes: S1: Obtain the information of the key joints of the vehicle body, and construct a data set of the key joints of the vehicle body according to the information of the key joints of the vehicle body; S2: Process the data set of the key joints of the vehicle body through a stiffness contribution degree quantification model to obtain a stiffness allocation weight vector set; S3: Process the stiffness allocation weight vector set through a dynamic stiffness allocation game model to obtain an optimal stiffness increment set; S4: Output the dynamic allocation result of stiffness by multi-scale stiffness collaborative optimization of the optimal stiffness increment set, and output a production plan for the key joints of the vehicle body according to the dynamic allocation result of stiffness.
[0022] In this embodiment, the obtaining of the information of the key joints of the vehicle body is specifically implemented through the following steps: S101: The body key joint information includes body key joint geometric information, body key joint material information, body key joint connection information, body key joint load condition information, and body key joint stiffness data; S101-1: The body key joint geometric information includes, but is not limited to, joint cross-sectional shape, joint thickness, and joint length; S101-2: The body key joint material information includes, but is not limited to, joint material elastic modulus and joint material density; S101-3: The body key joint connection information includes the position of the joint in the body and the constraint information of adjacent components of the joint; S101-4: The body key joint load condition information includes, but is not limited to, condition boundary conditions and condition load spectra.
[0023] It should be noted that the specific conditions in the body key joint load condition information include bending condition, torsion condition, and collision condition.
[0024] In this embodiment, the step of obtaining the stiffness distribution weight vector set by processing the body key joint data set through the stiffness contribution degree quantization model is specifically implemented as follows: S201: Construct a stiffness transfer matrix according to the body key joint data set. The mathematical expression of the stiffness transfer matrix is: , where, K g is the overall body stiffness, k i is the stiffness of the i-th joint, k n is the stiffness of the n-th joint, α max is the maximum local stress.
[0025] S202: Calculate the stiffness priority distribution weights for the stiffness transfer matrix to obtain the stiffness distribution weight vector set W = [w1, w2,..., w n ; The mathematical expression of the stiffness priority distribution weight calculation is: , where, w i is the stiffness priority distribution weight of the i-th joint, R i is the resource cost consumption of the i-th joint, R max is the maximum resource cost consumption of the joint, ||T(:,i)||2 is the L2 norm of the i-th column of the stiffness transfer matrix, ||T(:,j)||2 is the L2 norm of the j-th column of the stiffness transfer matrix, and n is the number of joints; The stiffness distribution weight vector set is the priority set of each joint for the global stiffness.
[0026] In this embodiment, the process of obtaining the optimal stiffness increment set by processing the stiffness allocation weight vector set through the dynamic stiffness allocation game model is specifically implemented through the following steps: S301: The dynamic stiffness allocation game model receives the stiffness allocation weight vector set and calculates the joint stiffness benefit through the stiffness benefit function; The mathematical expression of the stiffness benefit function is: , where ΔV i is the volume increment of the i-th joint, Δk i is the stiffness increase of the i-th joint, Δm i is the manufacturing cost increment of the i-th joint, β is the penalty coefficient, c i is the unit manufacturing cost coefficient of the i-th joint, P i is the material density of the i-th joint.
[0027] S302: Maximize the joint stiffness benefit through the stiffness increase strategy to obtain the optimal stiffness increment set; The stiffness increase strategy is that each joint is an independent decision maker. Under the joint resource constraints, the stiffness benefit of each joint is maximized while meeting the global stiffness requirements. The mathematical expression of the stiffness increase strategy is: and thus the mathematical expression of the stiffness-resource game equilibrium equation is: , where Δk i * is the stiffness increase of the i-th joint, P i is the material density of the i-th joint, V i is the volume of the i-th joint, k i is the stiffness of the i-th joint, m i is the manufacturing cost of the i-th joint.
[0028] Traverse each joint and calculate and output the optimal stiffness increment set Δk * =[Δk1 * ,..., Δk n * through the stiffness-resource game equilibrium equation.
[0029] In this embodiment, the process of outputting the stiffness dynamic allocation result by multi-scale stiffness co-optimization of the optimal stiffness increment set is specifically implemented through the following steps: S401: Preset joint design parameters, which include but are not limited to stiffness thickness, CNT content; S402: Preset joint design constraint conditions, where the joint design constraint conditions include vehicle body dimension constraint conditions, joint dimension constraint conditions, and material dimension constraint conditions; The mathematical expression of the vehicle body dimension constraint conditions is: , where α i is the position correction factor, K t is the preset target torsional stiffness of the joint design, K g is the overall torsional stiffness of the vehicle body, k i is the stiffness of the i-th joint, and n is the number of joints; The mathematical expression of the joint dimension constraint conditions is: , where m i is the mass of the i-th joint, m max,i is the maximum allowable mass of the i-th joint, k min,i is the lower limit of the stiffness of the i-th joint, k i is the stiffness of the i-th joint; The mathematical expression of the material dimension constraint conditions is: , where E i is the elastic modulus of the material of the i-th joint, e is the carbon nanotube reinforcement coefficient, CNT i is the CNT content of the i-th joint, t i is the characteristic thickness of the i-th joint, and L i is the characteristic length of the i-th joint; It should be noted that in terms of material dimensions, the local stiffness is improved by strengthening the material with carbon nanotubes CNT; S403: Update the joint design parameters through the joint design constraint conditions to obtain joint design update parameters; It should be noted that the joint design parameters are the joint design parameters in the optimal stiffness increment set; S404: Verify the joint design update parameters through multi-scale FEA and output the stiffness distribution result; It should be noted that the multi-scale FEA is used to verify the stiffness improvement effect. If the manufacturing constraints (such as stamping FLD) are violated, a dynamic penalty term is triggered and repeated until convergence, and then the stiffness distribution result is output. The stiffness distribution result is the final stiffness value of each joint.
[0030] A vehicle body key joint stiffness distribution system based on multi-objective optimization includes a data set construction module, a stiffness contribution quantification module, a dynamic stiffness distribution game module, and a stiffness collaborative optimization distribution module; The dataset construction module is used to obtain the information of the key body joints and construct a dataset of the key body joints; The stiffness contribution quantification module is used to process the dataset of the key body joints through a stiffness contribution quantification model to obtain a set of stiffness distribution weight vectors; The dynamic stiffness allocation game module is used to process the set of stiffness distribution weight vectors through a dynamic stiffness allocation game model to obtain an optimal set of stiffness increments; The stiffness collaborative optimization allocation module is used to output a stiffness dynamic allocation result through multi-scale stiffness collaborative optimization of the optimal set of stiffness increments, and output a production plan for the key body joints according to the stiffness dynamic allocation result.
[0031] As mentioned above, it is only a preferred embodiment of the present invention, and does not impose any form of limitation on the present invention. Although the present invention has been disclosed above with the preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to equivalent embodiments with equivalent changes within the scope of the technical solution of the present invention. However, as long as it does not depart from the content of the technical solution of the present invention, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention still fall within the scope of the technical solution of the present invention.
Claims
1. A method for stiffness distribution of key body joints based on multi-objective optimization, characterized in that Including: S1: Obtain the information of the key body joints, and construct a dataset of key body joints according to the information of the key body joints; S2: Process the dataset of key body joints through a stiffness contribution quantification model to obtain a set of stiffness distribution weight vectors; S3: Process the set of stiffness distribution weight vectors through a dynamic stiffness distribution game model to obtain a set of optimal stiffness increments; S4: Output a stiffness dynamic distribution result through multi-scale stiffness collaborative optimization of the set of optimal stiffness increments, and output a production plan for key body joints according to the stiffness dynamic distribution result.
2. The stiffness distribution method for key joints of a vehicle body according to claim 1, wherein The process of obtaining the set of stiffness distribution weight vectors in step S2 is as follows: S201: Construct a stiffness transfer matrix according to the dataset of key body joints; S202: Calculate the stiffness priority distribution weights for the stiffness transfer matrix to obtain a set of stiffness distribution weight vectors.
3. The method for distributing the stiffness of key joints of a vehicle body according to claim 2, characterized in that The mathematical expression of the stiffness transfer matrix in step S201 is: ， Among them, K g is the overall body stiffness, k i is the stiffness of the i-th joint, k n is the stiffness of the n-th joint, α max is the maximum local stress.
4. The method for distributing the stiffness of key body joints according to claim 2, characterized in that The mathematical expression of the stiffness priority distribution weight calculation in step S202 is: ， Among them, w i is the priority allocation weight of the stiffness of the i-th joint, and R i is the resource cost consumption of the i-th joint, and R max is the maximum resource cost consumption of the joint. ||T(:,i)||2 is the L2 norm of the i-th column of the stiffness transfer matrix, ||T(:,j)||2 is the L2 norm of the j-th column of the stiffness transfer matrix, and n is the number of joints.
5. The method for stiffness distribution of key body joints according to claim 1, characterized in that The process of obtaining the set of optimal stiffness increments in step S3 is as follows: S301: The dynamic stiffness distribution game model receives the set of stiffness distribution weight vectors, and calculates the joint stiffness benefit through a stiffness benefit function; S302: Maximize the joint stiffness benefit through a stiffness improvement strategy to obtain a set of optimal stiffness increments.
6. The method for distributing the stiffness of the key joints of the vehicle body according to claim 5, characterized in that The mathematical expression of the stiffness benefit function in step S301 is: ， Among them, ΔV i is the volume increment of the i-th joint, Δk i is the stiffness improvement of the i-th joint, Δm i is the manufacturing cost increment of the i-th joint, β is the penalty coefficient, c i is the unit manufacturing cost coefficient of the i-th joint, P i is the material density of the i-th joint.
7. The method for allocating the stiffness of the key joints of the vehicle body according to claim 1, characterized in that, The process of multi-scale stiffness collaborative optimization in step S4 is as follows: S401: Preset joint design parameters; S402: Preset joint design constraint conditions, where the joint design constraint conditions include body scale constraint conditions, joint scale constraint conditions, and material scale constraint conditions; S403: Update the joint design parameters through the joint design constraint conditions to obtain updated joint design parameters; S404: Verify the updated joint design parameters through multi-scale FEA and output a stiffness distribution result.
8. The method for stiffness distribution of key body joints according to claim 7, wherein The mathematical expression of the body scale constraint conditions in step S402 is: ， Among them, α i is the position correction factor, K t is the preset torsional stiffness of the joint design target, K g is the overall torsional stiffness of the vehicle body, k i is the stiffness of the i-th joint, and n is the number of joints.
9. The method for stiffness distribution of key body joints according to claim 7, characterized in that The mathematical expression of the joint scale constraint conditions in step S402 is: ， where m i is the mass of the i-th joint, and m max,i is the maximum allowable mass of the i-th joint, k min,i is the lower limit of the stiffness of the i-th joint, and k i is the stiffness of the i-th joint.
10. A body key joint stiffness distribution system based on multi-objective optimization, characterized in that The system is applied to the method for stiffness distribution of key body joints as described in any one of claims 1-9, and includes a dataset construction module, a stiffness contribution quantification module, a dynamic stiffness distribution game module, and a stiffness collaborative optimization distribution module; The dataset construction module is used to obtain the information of the key body joints and construct a dataset of key body joints; The stiffness contribution quantification module is used to process the dataset of key body joints through a stiffness contribution quantification model to obtain a set of stiffness distribution weight vectors; The dynamic stiffness distribution game module is used to process the set of stiffness distribution weight vectors through a dynamic stiffness distribution game model to obtain a set of optimal stiffness increments; The stiffness collaborative optimization distribution module is used to output a stiffness dynamic distribution result through multi-scale stiffness collaborative optimization of the set of optimal stiffness increments, and output a production plan for key body joints according to the stiffness dynamic distribution result.