Lightweight optimization method for front longitudinal beam of vehicle body
By setting the stress conditions and simulated experimental design, material replacement, upgrade and design optimization are carried out for automobile front longitudinal beam parts, which solves the problem of difficulty in achieving maximum lightweighting and design rationality confirmation in the existing technology, and achieves efficient weight reduction and performance improvement of parts.
Patent Information
- Application Number
- CN202411874015.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-19
- Publication Date
- 2025-05-06
AI Technical Summary
The existing lightweight optimization solution is difficult to achieve maximum lightweight in the design of automobile front longitudinal beams, and the lack of effective rationality confirmation in the design stage of individual components may lead to poor performance or unfeasible process.
A lightweight optimization method of the front longitudinal beam of the vehicle body is adopted. By setting the stress conditions, simulated experimental design and performance analysis are carried out, material replacement upgrades and design optimization are carried out for parts, and performance, weight, process production and cost are evaluated simultaneously.
The weight reduction of front longitudinal beam parts is achieved by more than 10%, the stiffness remains unchanged, the collision energy absorption effect is improved by more than 15%, and the process feasibility is ensured, which shortens the design time and reduces development costs.
Smart Images
Figure CN119939883A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of lightweight automobiles, and in particular to a lightweight optimization method for a front longitudinal beam of a vehicle body. Background Art
[0002] The front longitudinal beam is located at the front of the vehicle body. It plays a role in crushing and absorbing energy, preventing the cockpit from deforming, and protecting the safety of the cockpit occupants in the event of a head-on or offset collision. At the same time, it carries the large-mass modules of the vehicle body and plays a role in stabilizing the body structure. The lightweighting of the front longitudinal beam of the vehicle body is a weight reduction under the premise of ensuring the strength, rigidity, durability and safety of the vehicle.
[0003] However, the existing lightweight optimization scheme is to apply vehicle simulation trial optimization. The quality of the optimization scheme is closely related to the experience of engineers, and engineers need to optimize repeatedly. Moreover, weight reduction and cost reduction are carried out after the performance reaches the standard, which fails to achieve the maximum lightweight level. At the same time, during the design stage of a single component, engineers have no effective way to confirm whether the part design is reasonable enough. There may be problems such as unreasonable early design leading to substandard performance, or inability to produce under the performance standard, and excessive cost. Summary of the invention
[0004] In order to overcome the shortcomings of the existing technology, a lightweight optimization method for the front longitudinal beam of the vehicle body is provided, which takes into account the performance, weight, process production and cost for simultaneous evaluation, which can greatly shorten the design time and reduce the development cost.
[0005] In order to achieve the above object, the present invention adopts the following technical solutions:
[0006] A lightweight optimization method for a front longitudinal beam of a vehicle body, the method specifically comprising the following steps:
[0007] S1: The stress conditions of the front longitudinal beam under the vehicle body state are set as Y-direction stiffness, X-direction crushing force and energy absorption effect of the front longitudinal beam;
[0008] S2: Design simulation experiment based on the stress condition of the front longitudinal beam under the vehicle body state;
[0009] The analysis of the X-axis crushing force and the energy absorption effect of the front longitudinal beam is to set a rigid obstacle avoidance at the front end of the front longitudinal beam and set a constraint at the rear end to make the front longitudinal beam move in the obstacle avoidance direction;
[0010] The Y-direction stiffness verification is to set a force point at the front end of the front longitudinal beam and constrain the rear end at the same time;
[0011] S3: According to the experimental design, the original data is analyzed and the index is read, the crushing force and internal energy of the front longitudinal beam are read, and the Y-direction stiffness of the front longitudinal beam is calculated by curve reading after analysis;
[0012] S4: Carry out lightweight design optimization, replace and upgrade the materials of the front longitudinal beam parts, strengthen the weak rigidity areas, and optimize the location of the crushing area;
[0013] The formula for selecting material replacement and upgrading thickness is:
[0014]
[0015] Where: t max The maximum selected thickness of the material, in mm;
[0016] t 0 is the initial thickness of the material, in mm;
[0017] (σs) 0 is the initial yield strength of the material, in MPa;
[0018] (σs) 1 It is the yield strength of the material after optimization, in MPa;
[0019] S5: Perform performance analysis and index reading on the lightweight solution, read the crushing force and internal energy of the front longitudinal beam after optimization, and calculate the Y-direction stiffness of the front longitudinal beam through curve reading after analysis;
[0020] S6: Benchmark the performance index of the lightweight optimization solution with the performance index of the original data. If it fails, return to step S4;
[0021] S7: Perform forming analysis and verification on the lightweight optimization solution, and examine the thinning rate and forming limit of the front longitudinal beam according to the material performance index. If it fails, return to step S4;
[0022] S8: Use the cost analysis table to analyze the material cost, tooling cost, and production cost of the lightweight optimization solution to obtain the comprehensive cost of the parts.
[0023] Compared with the prior art, the present invention has the following beneficial effects:
[0024] At present, the optimization of vehicle lightweighting is based on the analysis of the whole vehicle. However, when this method optimizes the structure of specific parts, it is difficult to determine whether a single part has reached the optimal design solution, and the verification calculation is too large. This results in a long development cycle and increased costs. In the early stage of vehicle body development, the body design engineer intuitively confirms the rationality of the part structure designed by himself. The present invention aims to provide a simple lightweight optimization method for the front longitudinal beam parts of the vehicle body, which can quickly and effectively complete the lightweight optimization of the front longitudinal beam parts.
[0025] The performance analysis experiment design for the front longitudinal beam components or small assembly level of the present invention needs to comprehensively consider the actual state of the component in the vehicle body structure, and perform decoupling analysis based on its characteristics, decompose its main stress conditions and the role that the component can play under these conditions. Simulation experiments are performed according to the working conditions, and optimization iterations are performed.
[0026] The present invention compares and analyzes the performance of the front longitudinal beam assembly components, verifies the part forming performance, changes the material of the body parts in a targeted manner, and optimizes the part design. This can achieve a weight reduction of more than 10% for the parts, maintain the part stiffness unchanged, and improve the collision energy absorption effect by more than 15% without losing the process feasibility. BRIEF DESCRIPTION OF THE DRAWINGS
[0027] Figure 1 It is a flow chart of the present invention.
[0028] Figure 2 It is a comparison diagram of the part optimization process of the present invention.
[0029] Figure 3 This is a comparison chart of the crushing forces of multiple versions of the optimized parts of the present invention.
[0030] Figure 4 This is a comparison chart of the energy content of multiple versions of the parts optimized according to the present invention.
[0031] Figure 5 This is a comparison chart of the Y-axis stiffness of multiple versions of the parts optimized according to the present invention.
[0032] Figure 6 It is a verification diagram of the formability of the parts of the present invention. DETAILED DESCRIPTION
[0033] The following will be combined with examples of the present invention to clearly and completely describe the technical solution of the present invention. Obviously, the implementation case described is only one of the embodiments of the present invention, and those skilled in the art can refer to the content of this article and appropriately improve the process parameters to achieve it. It is particularly important to point out that all similar replacements and modifications are obvious to those skilled in the art, and they are all considered to be included in the present invention. The method and application of the present invention have been described through preferred embodiments, and relevant personnel can obviously modify or appropriately change and combine the methods and applications described herein without departing from the content, spirit and scope of the present invention to implement and apply the technology of the present invention.
[0034] like Figure 1-6 As shown, a lightweight optimization method for a front longitudinal beam of a vehicle body, the method specifically comprises the following steps:
[0035] Step S1, analyze the stress conditions of the front longitudinal beam under the vehicle body state. In actual working conditions, the front longitudinal beam of the vehicle body mainly bears three stress conditions. The first is the X-direction crushing force of the vehicle body transmitted by the bumper and the energy absorption box during the vehicle collision. The front longitudinal beam mainly plays the role of anti-deformation and crushing energy absorption under this condition. The main assessment target should be the crushing force and deformation energy absorption effect; the second is the Z-direction pressure brought by the large mass module of the vehicle body. This condition mainly assesses the Z-direction bearing capacity of the front longitudinal beam, which is specifically manifested as the Z-direction stiffness; the third is the stability of the front cabin during vehicle driving and turning. The front longitudinal beam mainly plays the role of stabilizing the swing of the front cabin under this condition, which is specifically manifested as the Y-direction stiffness of the front longitudinal beam. The Z-direction bearing capacity is closely related to the structures of the vehicle chassis, suspension, front shock tower, front upper longitudinal beam, etc. The single optimization of the front longitudinal beam thickness has a small influence factor, and only the Y-direction stiffness, X-direction crushing force and front longitudinal beam energy absorption effect need to be verified.
[0036] Step S2, designing a simulation experiment according to the stress conditions, wherein the analysis of the crushing force and energy absorption effect in the X-axis can be performed by setting a rigid obstacle avoidance at the front end of the front longitudinal beam and setting a constraint at the rear end so that the front longitudinal beam is displaced in the obstacle avoidance direction; the Y-axis stiffness verification can be performed by setting a stress point at the front end of the front longitudinal beam and constraining the rear end at the same time.
[0037] Step S3, according to the experimental design, the original data is subjected to performance analysis and index reading, the crushing force and internal energy of the front longitudinal beam are read, and after analysis, the Y-direction stiffness of the front longitudinal beam is calculated by curve reading.
[0038] Step S4, perform lightweight design optimization, and perform material replacement and upgrading for the front longitudinal beam parts; through design optimization, add anti-bending structure and strengthen the weak rigidity area; by adding deformation guiding structure, optimize the position of crushing area, etc.; material replacement and upgrading thickness selection formula is selected
[0039] Step S5, performing performance analysis and index reading on the lightweight solution, reading the crushing force and internal energy of the front longitudinal beam after optimization, and calculating the Y-direction stiffness of the front longitudinal beam through curve reading after analysis.
[0040] Step S6, comparing the performance index of the lightweight optimization solution with the performance index of the original data, if unqualified, return to step S4.
[0041] Step S7, perform forming analysis and verification on the lightweight optimization solution, and examine the thinning rate of the front longitudinal beam, forming limit, etc. according to the material performance indicators. If it is unqualified, return to step S4.
[0042] Step S8, using a cost analysis table to analyze the material cost, tooling cost, and production cost of the lightweight optimization solution to obtain the comprehensive cost of the parts.
[0043] like Figure 2As shown in the figure, D01 is the original version, and D02-D06 are the optimized versions. Figure 3-5 As shown, Figure 3 is the crush force curve, Figure 4 is the internal energy curve, Figure 5 It is the lateral stiffness curve. If the curve is lower than D01, it will not work, and if it is higher, it will be effective.
[0044] Figure 6 This is the part formability verification diagram of the present invention. After the optimization is completed, the part basically achieves the optimal design solution. In the later vehicle analysis process, if the decomposition index is adjusted, the performance index of the optimized part can be adjusted, and iterative optimization can be continued.
[0045] Example:
[0046] The design data of the front longitudinal beam of a certain vehicle model was selected for optimization, and the working condition was set as a rigid obstacle avoidance at the front end, with a crushing distance of 30mm. The original thickness of the inner and outer panels of the part was 1.8mm, and both the inner and outer panels were made of DP590. The optimized thickness was 1.6mm for the inner and outer panels, of which the inner panel was made of DP780 and the outer panel was made of DP980. A total of 6 versions of optimization analysis were performed, and the specific solutions are shown in the table below:
[0047]
[0048]
[0049] Through analysis, the data of the D01 basic version show that the Y-axis stiffness is 388.95N / mm, the axial crushing force is 75.68kN, the peak value of the crushing internal energy is 1342.25kJ, and the total weight of the part is 4.617kg. These are set as the benchmark indicators.
[0050] Initially optimize the material and thickness of the parts, and optimize the thickness of the inner and outer plates to 1.6mm, of which the inner plate is DP780 and the outer plate is DP980. Perform D02 version analysis, and the analysis results show that the Y-axis stiffness is 345.73N / mm, the axial crushing force is 85.3kNN, the peak value of the crushing internal energy is 1490.74kJ, and the total weight of the parts is 4.103kg. The stiffness decreases by about 11.12%, the part weight decreases by 11.13%, the crushing force increases by 12.7%, and the internal energy absorption increases by 11.06%.
[0051] According to the analysis results of version D02, the parts were further optimized, and crush ribs were added at the front end to increase the energy absorption effect. The analysis of version D03 showed that the weight remained basically unchanged, the axial crushing force increased to 90.45kN, and the internal energy peak was 1673.12kJ. They increased by +19.52% and +24.65% respectively. However, the Y-axis stiffness decreased to 288.18N / mm, a decrease of about -25.9%.
[0052] After optimization, the crushing performance of the part has been greatly improved, but the Y-direction stiffness has decreased significantly. Based on the results of version D03, the optimization of versions D04, D05, and D06 continues. The specific optimization content is to optimize the part shape and improve the Y-direction stiffness. Among them, the Y-direction stiffness of the D04 version is 341.65N / mm, which is a decrease of -12.2% compared with the basic index; the Y-direction stiffness of the D05 version is 347.71N / mm, which is a decrease of -10.6% compared with the basic index; the Y-direction stiffness of the D06 version is 374.95N / mm, which is a decrease of -3.6% compared with the basic index. The decrease in stiffness is small, and it can be defaulted to be completed.
[0053] Finally, the new optimization method was used to reduce the weight of the part by 11.04% and increase the crush energy absorption by +24.65%. The part optimization was successful.
[0054] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.
Claims
1. A lightweight optimization method for a front longitudinal beam of a vehicle body, characterized in that: The method specifically comprises the following steps: S1: The stress conditions of the front longitudinal beam under the vehicle body state are set as Y-direction stiffness, X-direction crushing force and energy absorption effect of the front longitudinal beam; S2: Design simulation experiment based on the stress condition of the front longitudinal beam under the vehicle body state; The analysis of the X-axis crushing force and the energy absorption effect of the front longitudinal beam is to set a rigid obstacle avoidance at the front end of the front longitudinal beam and set a constraint at the rear end to make the front longitudinal beam move in the obstacle avoidance direction; The Y-direction stiffness verification is to set a force point at the front end of the front longitudinal beam and constrain the rear end at the same time; S3: According to the experimental design, the original data is analyzed and the index is read, the crushing force and internal energy of the front longitudinal beam are read, and the Y-direction stiffness of the front longitudinal beam is calculated by curve reading after analysis; S4: Carry out lightweight design optimization, replace and upgrade the materials of the front longitudinal beam parts, strengthen the weak rigidity areas, and optimize the location of the crushing area; S5: Perform performance analysis and index reading on the lightweight solution, read the crushing force and internal energy of the front longitudinal beam after optimization, and calculate the Y-direction stiffness of the front longitudinal beam through curve reading after analysis; S6: Benchmark the performance index of the lightweight optimization solution with the performance index of the original data. If it fails, return to step S4; S7: Perform forming analysis and verification on the lightweight optimization solution, and examine the thinning rate and forming limit of the front longitudinal beam according to the material performance index. If it fails, return to step S4; S8: Use the cost analysis table to analyze the material cost, tooling cost, and production cost of the lightweight optimization solution to obtain the comprehensive cost of the parts.
2. The lightweight optimization method for a front longitudinal beam of a vehicle body according to claim 1, characterized in that: In S4, the formula for selecting the thickness of the material replacement upgrade is: Where: t max The maximum selected thickness of the material, in mm; t0 is the initial thickness of the material, in mm; (σs)0 is the initial yield strength of the material, in MPa; (σs)1 is the yield strength of the material after optimization, unit: MPa.