Commercial vehicle steel-aluminum hybrid body-in-white design method, system, equipment and medium

Abstract

The invention provides a commercial vehicle steel-aluminum hybrid body-in-white design method, system and device and a medium, and belongs to the field of commercial vehicle design. Design data based on commercial vehicle performance and weight reduction target parameters are preset; determining a design target; calculating the torsional rigidity, bending rigidity, modal frequency and sensitivity of the body-in-white of the commercial vehicle to obtain body-in-white structure information of the commercial vehicle; carrying out material replacement by replacing steel with aluminum, and updating the body-in-white model; performing simulation analysis on the body-in-white model to obtain bending rigidity, torsional rigidity and modal values of the body-in-white; and judging whether the bending rigidity, the torsional rigidity and the modal value of the body-in-white conform to the design data or not after the material is replaced. According to the method, by judging whether the materials meet the requirements after being replaced or not, it can be ensured that the finally designed commercial vehicle body-in-white meets the requirements in the aspects of quality, fuel economy and the like of body-in-white products with the performance and weight reduction meeting design data.

Description

Technical Field

[0001] The present invention belongs to the field of commercial vehicle design, and in particular relates to a commercial vehicle steel-aluminum hybrid body-in-white design method, system, equipment and medium. Background Art

[0002] At present, with the rapid development of the commercial vehicle industry and the society's increasing requirements for overloading and over-limit control and vehicle transportation costs, the lightweight design of commercial vehicles has become a hot topic in industry research as well as a difficulty.

[0003] Among them, the weight and cost of the cab body-in-white account for a large proportion of the commercial vehicle. Therefore, the body-in-white structural design is an important research object for the lightweight design of commercial vehicles. The body-in-white structure has many design performance requirements, such as the body bending stiffness and torsional stiffness that affect the durability of the vehicle structure, etc. These design performances are contradictory to the body mass and cost to a certain extent. Therefore, how to balance the light weight of the body with high performance and low cost is an important consideration in the body-in-white design.

[0004] In the existing technical solutions, material data, performance data and connection information are scattered in different documents, and there is no centralized database. The integration of various types of data leads to insufficient design reference data, which affects the accuracy and comprehensiveness of the design. The existing technology relies only on experience or simple estimation when determining design variables, resulting in inaccurate selection of design variables and inability to effectively optimize vehicle body performance and weight. The key role of components in vehicle body performance and weight cannot be effectively known, resulting in the same treatment of all components in the design process, which is not targeted. As a result, it is impossible to accurately understand the impact of each component on the overall performance. When replacing materials, there may be a lack of comprehensive consideration of vehicle body structure and performance, resulting in reduced vehicle body performance or poor weight reduction effects. Summary of the invention

[0005] The present invention provides a commercial vehicle steel-aluminum hybrid body-in-white design method. The method can ensure that the commercial vehicle body-in-white designed in the end meets the performance and weight reduction requirements of the body-in-white product that meets the design data by judging whether the material meets the requirements after replacement. The quality, fuel economy and other requirements can be guaranteed.

[0006] Methods include: Establish a commercial vehicle body-in-white material library, performance benchmark library, and body component connection method library, and preset design variables based on commercial vehicle performance and weight reduction target parameters; Determine the design variables based on the performance and weight of the commercial vehicle body according to the preset body-in-white model and performance benchmarking library information; Calculate the torsional stiffness, bending stiffness, modal frequency and sensitivity of the body-in-white structural performance parameters to the component thickness variables to obtain the commercial vehicle body-in-white structural information; Formulate the body-in-white parts to replace steel with aluminum according to the structural characteristics, and update the body-in-white model; The body-in-white model with updated materials is simulated and analyzed to obtain the bending stiffness, torsional stiffness and modal values ​​of the body-in-white; Determine whether the bending stiffness, torsional stiffness and modal values ​​of the body in white meet the design data after the material is replaced.

[0007] It should be further explained that in the method, the calculation formula for the torsional stiffness of the commercial vehicle body in white is: ; Where: k is the torsional stiffness; T is the applied torque; D1 is the displacement of the left loading point of the front overhang based on the preset direction; D2 is the displacement of the right loading point of the front overhang based on the preset direction; L is the distance between the loading points.

[0008] It should be further explained that in the method, the bending stiffness is calculated as follows:

[0009] Where: k2 is the bending stiffness; F is the total load of the front seat; D3 is the maximum displacement of the left longitudinal beam based on the preset direction; D4 is the maximum displacement of the right longitudinal beam based on the preset direction.

[0010] It should be further explained that in the method, the modal frequency is calculated as follows: ; Where: K3 is the modal frequency; ω is the angular velocity; M is the mass matrix; The sensitivity S of the body-in-white structural performance parameters to the component thickness variation is calculated as:

[0011] Where: is the objective function, the derivative of f(x) with respect to the initial variable xi.

[0012] It is further necessary to explain that the material replacement method of using aluminum to replace steel includes: using steel materials for the frame crossbeam, longitudinal beam, and A-pillar reinforcement plate; The exterior skin parts are made of aluminum alloy; Discrete single impact hard point is made of die-cast aluminum alloy; The threshold crossbeam adopts a grid-like staggered rib structure.

[0013] It should be further explained that the constraint data of the body-in-white bending stiffness loading point is set in the method; The constraint data of the left and right front overhangs and the left and right rear overhangs are SPC123456; the two seats of the commercial vehicle are loaded with 1367.1N in the preset direction respectively; Set the constraint data of the torsional stiffness loading point of the body in white; The constraint data of the left and right rear suspensions in the front torsion constraint is SPC123456; 2935.8N are loaded in the preset directions of the left and right front suspensions respectively; In the rear torsion constraint, the constraint data of the left and right front suspension and the left and right rear suspension are SPC123456, and 1584.6N are loaded in the preset directions of the left and right rear suspension respectively.

[0014] It should be further explained that the design data based on the commercial vehicle performance and weight reduction target parameters are expressed as

[0015] Where f(x) is the objective function; n is the number of functions; r(x) and k(x) are the inequality constraint function and equality constraint function respectively; p and q are the number of constraint functions respectively; x=(x1,x2,…,x n ) is the design variable, is the material thickness, and is the material yield design value; m is the number of design variables; x L and x U are the upper and lower limits of the design variables, respectively, constraining the range of the design variables; the design variable value x=(x1,x2,…,x n ) is called a feasible solution.

[0016] The present application also provides a commercial vehicle steel-aluminum hybrid body-in-white design system, the system comprising: Data pre-definition module, used to establish a commercial vehicle body-in-white material library, performance benchmark library, and body component connection method library, and preset design variables based on commercial vehicle performance and weight reduction target parameters; The target setting module is used to determine the design variables based on the performance and weight of the commercial vehicle body according to the preset body-in-white model and performance benchmarking library information; The parameter calculation module is used to calculate the torsional stiffness, bending stiffness, modal frequency and sensitivity of the body-in-white structural performance parameters to the thickness variables of the components to obtain the body-in-white structural information of the commercial vehicle; Material replacement module, used to formulate material replacement of aluminum instead of steel for body-in-white parts according to structural characteristics, and update the body-in-white model; The simulation analysis module is used to simulate and analyze the body-in-white model after the material is updated to obtain the bending stiffness, torsional stiffness and modal values ​​of the body-in-white; The parameter determination module is used to determine whether the bending stiffness, torsional stiffness and modal values ​​of the body in white meet the design data after the material is replaced.

[0017] According to another embodiment of the present application, an electronic device is provided, comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, wherein the processor implements the steps of the commercial vehicle steel-aluminum hybrid body-in-white design method when executing the program.

[0018] According to another embodiment of the present application, a storage medium is provided, on which a computer program is stored, and when the computer program is executed by a processor, the steps of the commercial vehicle steel-aluminum hybrid body-in-white design method are implemented.

[0019] It can be seen from the above technical solutions that the present invention has the following advantages: The commercial vehicle steel-aluminum hybrid body-in-white design method provided in this application provides a material selection basis for the design by establishing various databases and preset design variables. The principles and process parameters of various connection methods are recorded based on the connection method library to ensure that the appropriate method is selected when the steel-aluminum hybrid connection is made. This improves the design efficiency.

[0020] The design variables are determined based on the preset body-in-white model and performance benchmarking library information, which can be combined with the actual body performance and weight requirements of commercial vehicles. Component-related parameters are used as design variables to achieve targeted design. This solves the problem that the existing technology relies only on experience or simple estimation, resulting in inaccurate selection of design variables and inability to effectively optimize body performance and weight.

[0021] The commercial vehicle body-in-white structural information is obtained by calculating the torsional stiffness, bending stiffness, modal frequency and sensitivity of the body-in-white structural performance parameters to the thickness variables of the components; the importance of each body component under different performance indicators can be understood. For components with high sensitivity to bending stiffness, effective material replacement and structural optimization can be achieved. A material replacement strategy of replacing steel with aluminum is formulated based on structural characteristics, which can achieve effective weight reduction while ensuring the performance of the body. For load-bearing parts, aluminum is selected to replace parts that have little impact on performance but obvious weight reduction effects; this allows designers to understand the changes in the body structure after material replacement.

[0022] By simulating and analyzing the model after the material is updated, it is determined whether the bending stiffness, torsional stiffness and modal values ​​of the body-in-white meet the design data after the material is replaced. The bending stiffness, torsional stiffness and modal values ​​of the body-in-white can be accurately obtained. By comparing the calculation results with the full steel body-in-white model, the changes in the performance of the body-in-white after the material replacement are understood. For those that meet the design data, the body-in-white model can be determined. If it does not meet the requirements, the reasons can be analyzed and improved in time. In this way, the accuracy and efficiency of the design of the steel-aluminum hybrid body-in-white of commercial vehicles are improved, and the lightweight goal of the body-in-white is achieved. Then, by calculating the sensitivity of the performance parameters, the structural characteristics of the body are understood, and the components that affect the performance and weight of the body are located, and precise design is achieved, which solves the problem of unclear material selection design variables in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solution of the present invention, the accompanying drawings required for use in the description will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0024] Figure 1 A flow chart of the design method for a steel-aluminum hybrid body-in-white for commercial vehicles; Figure 2 This is an example of a commercial vehicle body-in-white model; Figure 3 This is an example of one side of a commercial vehicle body-in-white model; Figure 4 This is an overall example diagram of a commercial vehicle body-in-white model; Figure 5 Design system schematic for commercial vehicle steel-aluminum hybrid body-in-white; Figure 6 Schematic diagram of an electronic device. DETAILED DESCRIPTION

[0025] The commercial vehicle steel-aluminum hybrid body-in-white design method provided in this application first determines the design variables and design goals based on the commercial vehicle performance and weight reduction target parameters, obtains sensitivity through simulation analysis, and then formulates material replacement strategies and performs structural design optimization based on the analysis results. The entire process of this application is based on accurate data to achieve the commercial vehicle steel-aluminum hybrid body-in-white design. After simulating and analyzing the existing body-in-white model, this application can obtain the sensitivity coefficients of performance indicators such as bending stiffness, torsional stiffness, and modal of the components, so that users can learn that commercial vehicle components have a greater impact on performance, thereby focusing on key components during material replacement and structural optimization, achieving precise optimization, and improving design efficiency and quality.

[0026] For the commercial vehicle steel-aluminum hybrid body-in-white design method provided in this application, when determining the performance target, the existing body-in-white performance is compared with the benchmark library data to ensure that the newly designed steel-aluminum hybrid body-in-white is not inferior to the original all-steel body-in-white in terms of bending stiffness, torsional stiffness, modal and other performance. During the material replacement process, the performance of each replacement part is analyzed, and the strength and stiffness of the replaced body pillar can be analyzed to ensure that it will not fail when subjected to various loads during vehicle driving.

[0027] This application uses the characteristics of aluminum density and a reasonable material replacement strategy to achieve significant weight reduction of the body in white. Then, through a preliminary analysis of material replacement in different parts, the possible weight reduction effect of using aluminum in each part is calculated, thereby determining the overall weight design target.

[0028] The specific steps of the commercial vehicle steel-aluminum hybrid body-in-white design method are described in detail below. For the purpose of illustration rather than limitation, specific details such as specific system structures and technologies are proposed to facilitate a thorough understanding of the embodiments of the present application. However, it should be clear to those skilled in the art that the present application can also be implemented in other embodiments without these specific details.

[0029] The phrases such as "one embodiment" or "some embodiments" described in the present application mean that the specific features, structures or characteristics described in the embodiment are included in one or more embodiments of the present application. Therefore, the phrases such as "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments" etc. that appear in different places in the present application do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways.

[0030] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] See also Figure 1 The figure is a flow chart of a commercial vehicle steel-aluminum hybrid body-in-white design method in a specific embodiment, the method comprising: S101: Establish a commercial vehicle body-in-white material library, a performance benchmark library, and a body component connection method library, and preset design variables based on commercial vehicle performance and weight reduction target parameters.

[0032] In some embodiments, the commercial vehicle body-in-white material library can be established by collecting various steel and aluminum data used in the manufacture of commercial vehicle bodies-in-white, including: the content of carbon, manganese, silicon and other elements in steel, the proportion of alloy elements in aluminum, and also mechanical performance indicators, such as yield strength, tensile strength, elongation, etc.

[0033] The performance benchmarking library is established based on the commonly used commercial vehicle body-in-white as the benchmarking parameter. It can involve light, medium and heavy commercial vehicles, reflecting the performance parameters in different application scenarios. When building the performance benchmarking library, the data of the performance benchmarking library is matched with the corresponding vehicle model, and the test conditions can be used in the subsequent design process to accurately perform comparative analysis.

[0034] The established library of body component connection methods includes: the process and related parameters of riveting connection method, the process and related parameters of welding connection method, and the process of adhesive connection method, etc.

[0035] In this embodiment, body parts that have an impact on performance and weight are selected as design variables based on the structural characteristics and material distribution of the commercial vehicle body-in-white.

[0036] Specifically, components such as body beams, pillars and other load-bearing parts can be selected. By optimizing the materials and dimensions of the components, weight reduction and performance optimization can be effectively achieved.

[0037] For design variables, their reasonable range of variation can be determined based on the actual manufacturing process feasibility, material performance limitations and structural design requirements.

[0038] For example, in this embodiment, aluminum alloy plates can be selected and the corresponding thickness can be set as a design variable to ensure that they can be processed through the process to avoid excessive weight increase due to excessive thickness of the plates, while also ensuring the strength requirements for vehicle use.

[0039] The contents of the commercial vehicle body-in-white material library of this embodiment may be shown in the following table.

[0040]

[0041] S102: Determine design variables based on commercial vehicle body performance and weight according to a preset body-in-white model and performance benchmarking library information.

[0042] In some embodiments, a preset body-in-white model is analyzed to determine the specific functions of various body components and their interactions and relationships.

[0043] Optionally, this embodiment uses model analysis software to obtain the length, width, thickness, etc. of each component of the vehicle body, and then obtains the shape of each component of the vehicle body and the connection method between the components.

[0044] Compare the bending stiffness, torsional stiffness, modal frequency, etc. of the preset body-in-white model with the data in the performance benchmark library. Find out the gaps between the performance indicators and the benchmark models, and identify the performance directions that need to be improved.

[0045] It should be noted that if the average bending stiffness of the benchmark vehicle model is higher than the preset body-in-white model, the body parts with a greater impact on the bending stiffness will be targeted when determining the design variables.

[0046] The design variables for performance in this embodiment may involve vehicle body pillars, cross beams, etc., and specific design variables include structural dimensions and material properties.

[0047] The connection method and connection strength of the connecting parts may involve the design of welding process or rivet spacing. The selection of welding process, the number and spacing of rivets, etc. are used as design variables to improve the performance of the car body by optimizing the connection method of the parts.

[0048] The weight design variables of this embodiment involve non-load-bearing parts of the vehicle body, such as the body outer panels, interior trim panels, etc. For the body beam, if the structural optimization design is also carried out while meeting the performance requirements, the cross-sectional shape of the body beam can be changed or lightweight materials can be used.

[0049] S103: Calculate the torsional stiffness, bending stiffness, modal frequency, and sensitivity of the body-in-white structural performance parameters of the commercial vehicle to the component thickness variable to obtain the body-in-white structural information of the commercial vehicle.

[0050] The torsional stiffness of the commercial vehicle body in white calculated in this embodiment can be simulated by applying torque to the finite element model of the body in white and adjusting it according to the constraints, the torsional force on the body when the vehicle is driving under actual working conditions is simulated, the torsional angle of the body under a certain load is calculated using finite element analysis software, and the torsional stiffness value is obtained according to the definition of torsional stiffness.

[0051] Bending stiffness is to apply a vertical downward concentrated force or uniformly distributed force above the front and rear axles of the model to simulate the bending of the vehicle body when the vehicle is loaded, and calculate the bending deformation of the vehicle body after loading.

[0052] The modal frequency is the natural vibration characteristic of the vehicle body. By calculating the vibration frequency of the vehicle body at different orders, the natural characteristics of the vehicle body under different vibration modes can be obtained.

[0053] This embodiment calculates the sensitivity of the body-in-white structural performance parameters to the component thickness variables, and determines the component thickness variables that affect the body performance. Each thickness variable is adjusted, and the value of one thickness variable is changed each time, while keeping the other variables unchanged. The finite element analysis is re-calculated to calculate the above-mentioned performance parameters such as torsional stiffness, bending stiffness and modal frequency.

[0054] This embodiment calculates the sensitivity information of each component thickness variable to each performance parameter based on the ratio of the change in the performance parameter to the change in the thickness variable.

[0055] S104: Formulate material replacement of aluminum for body-in-white parts based on structural characteristics, and update the body-in-white model.

[0056] It should be noted that the body-in-white structure of commercial vehicles includes the force distribution of the vehicle body. By analyzing the force under various working conditions during vehicle driving, the force path and load-bearing capacity of the body beam, pillars and other load-bearing components can be clarified; the functions and effects of the body outer panels, interior panels and other components can be understood.

[0057] Combined with the design variables of steps S102 to S103, for the load-bearing parts, aluminum can be used to replace steel in the parts that have little impact on the overall performance but significant weight reduction effect. For the body cross beams that are relatively less stressed, aluminum alloy materials can be used.

[0058] In some specific embodiments, considering that aluminum alloy materials may not be used for components in the force-bearing and force-transmitting paths, in order to ensure the safety and stability of the entire body-in-white frame structure, aluminum alloy materials are not used for the main components in the force-bearing and force-transmitting paths, such as frame crossbeams, longitudinal beams, and A-pillar reinforcement plates.

[0059] In this embodiment, aluminum alloy material is preferably used for the exterior skin parts.

[0060] For example, the main function of the exterior skin parts such as the side outer panels is decoration, they are subjected to small forces, and have little impact on the entire body-in-white frame structure. Therefore, 5 series and 6 series aluminum alloy stamping plates can be used.

[0061] For discrete single impact hard points, consider using die-cast aluminum alloy materials. For local single-point stress locations, multiple reinforcement plates can be designed to meet the superimposed reinforcement effect. It is also possible to design divergent ribs to transfer and disperse stress with the stress point as the center, so that one casting can replace multiple steel plate reinforcements, such as the shock absorber connection point.

[0062] Considering the single force direction, uniform cross-section and regular surface, the die-cast aluminum alloy material with a shape relative to the force direction can be designed.

[0063] For example, the sill beam of a commercial vehicle is subjected to force in two directions: front and rear, and left and right. According to the force characteristics and the structure of the casting, a grid-like staggered rib structure can be made. By giving full play to the structural characteristics of the casting, a mesh rib structure with uniform force that cannot be achieved by steel stampings can be designed. At the same time, the low density of aluminum can be utilized. Under the premise of appropriately increasing the thickness, the weight and performance are still better than those of steel structures.

[0064] S105: Perform simulation analysis on the body-in-white model after the material is updated to obtain the bending stiffness, torsional stiffness and modal values ​​of the body-in-white.

[0065] In this embodiment, the updated body-in-white model can be solved and calculated using finite element analysis software. During the calculation process, the convergence and calculation time are calculated. If the calculation is abnormal or the calculation time is too long, the calculation parameters set by the model are adjusted. The calculation is performed again. After the calculation is completed, the performance values ​​of the body-in-white, such as bending stiffness, torsional stiffness and modal frequency, are extracted from the finite element analysis software, and the results are preliminarily sorted and recorded.

[0066] Specifically, the simulation calculation process can be configured, including model import, working condition setting, calculation parameter selection, result monitoring and other links. In the process of executing the finite element analysis software to realize the simulation analysis, the calculated bending stiffness, torsional stiffness and modal values ​​can be visualized in combination with visualization. The performance of the body in white under different performance indicators can be analyzed through charts, cloud maps and other forms.

[0067] In some specific embodiments, the body-in-white model is as follows: Figures 2 to 4 As shown, the body-in-white bending stiffness loading points and constraint parameters can be set.

[0068] Specifically, the constraint parameters can be set to constrain the left and right front overhangs and the left and right rear overhangs SPC123456. The loading points are the two seats, each loaded with 1367.1N in the -Z direction.

[0069] The torsional stiffness loading point of the body in white is constrained by the front torsion constraint, the left and right rear overhang SPC123456. The torsional stiffness loading point of the body in white is the left and right front overhang ±Z direction, which is loaded with 2935.8N respectively.

[0070] The rear torsion constraint is SPC123456 for the left and right front suspension and the left and right rear suspension, and the left and right rear suspension is loaded with 1584.6N in the ±Z direction respectively.

[0071] The body-in-white mode is the OptiStruct solver, the constraint is the free mode, and the excitation frequency is: Eigra 0-100Hz.

[0072] It can be seen that after establishing an accurate finite element model of the commercial vehicle body-in-white, this embodiment sets the model according to the given constraints and loading parameters to calculate the bending stiffness, constrains the left and right front overhangs and left and right rear overhangs SPC123456 in the finite element model, simulates the actual suspension connection state of the vehicle, and limits the displacement of related parts. At the same time, a force of 1367.1N in the -Z direction is applied to the two seat positions to simulate the loading of the passenger weight on the vehicle body.

[0073] For two seat positions, each of which has a force of 1367.1N in the Z direction, the vertical displacement of the seat position under loading conditions can be obtained through finite element analysis. A displacement sensor can be used to measure the vertical displacement of the body at the seat. Here, the loading force F=1367.1N for each seat is known, and the displacement of the loading point is measured as d. For a single seat loading condition, the bending stiffness G=1367.1 / d.

[0074] Since two seats are loaded, and assuming that the bending deformation of the body under this loading mode is linear, the total bending stiffness G Z It can be calculated based on the parallel spring, that is, G Z =2×(1367.1 / d).

[0075] In this way, the displacement results are used for bending stiffness calculation, which also ensures the accuracy of measurement and loading force.

[0076] When calculating torsional stiffness, the front torsion constraint is set to the left and right rear suspension SPC123456. When simulating the front torsion condition, the SPC123456 of the left and right rear suspension of the body in white is fixed to limit the displacement in space. Then, a force of 2935.8N is loaded in the positive and negative directions of the vertical direction of the left and right front suspensions respectively. These two forces of equal magnitude and opposite direction will generate a torque on the front suspension of the body in white, simulating the force conditions that may cause the front part of the body to twist during driving.

[0077] The rear torsion constraint is SPC123456 for the left and right front overhangs and the left and right rear overhangs, that is, multiple specific points of the front and rear overhangs of the vehicle body are fixed. Then, a force of 1584.6N is loaded in the ±Z direction of the left and right rear overhangs respectively, which is also two forces in opposite directions, to generate torque at the rear of the vehicle body, simulating the torsional conditions that the rear part of the vehicle may be subjected to during driving. By setting different constraints and loadings on different front and rear parts, the torsional force that the commercial vehicle body-in-white is subjected to in various actual driving scenarios is simulated.

[0078] The specific implementation method is torsional stiffness G N Defined as the ratio of torque Z to torsion angle J, that is, G N =Z / J.

[0079] Under loading, for the forward torsion condition, the torque Z 前 It can be calculated by multiplying the force and the lever arm.

[0080] Assume that the vertical distance from the left and right front suspension loading points to the rear suspension constraint point is C 前 , then Z 前 =2935.8×C 前 ×2. For the rear torsion condition, assume that the vertical distance from the left and right rear suspension loading points to the front suspension constraint point is Z前 =1584.6×C 后 ×2.

[0081] The calculation of torsional stiffness in this embodiment is based on the definition of torsional stiffness. The torsional stiffness under the forward torsional condition is Gz=Z 前 / β 前 , the torsional stiffness under the torsion condition is Gz=Z 后 / β 后 The two calculation results can be used to evaluate the torsional stiffness performance of the commercial vehicle body-in-white under different torsional conditions.

[0082] For modal analysis, the OptiStruct solver was used, set to free mode, and the excitation frequency was defined as Eigra 0 - 100Hz. With these parameter settings, the finite element analysis software was used to calculate the body-in-white's torsional stiffness, bending stiffness, modal frequency and other performance parameters, and calculate the sensitivity of the structural performance parameters to the component thickness variables.

[0083] It can be seen that the constraint and loading parameter settings of this embodiment make the calculated performance parameters closer to the actual use conditions of commercial vehicles. Through sensitivity analysis, it is possible to identify which component thickness changes affect the overall structural performance of the vehicle body, and assist designers in clarifying which components need to be focused on in subsequent material replacement and structural optimization.

[0084] S106: Determine whether the bending stiffness, torsional stiffness and modal values ​​of the body in white meet the design data after the material is replaced.

[0085] In this embodiment, the bending stiffness, torsional stiffness and modal values ​​of the body-in-white obtained by simulation analysis in step S105 are compared with the pre-set design data. For example, the design variables require that the bending stiffness of the body-in-white is not less than a certain value, the torsional stiffness is within a certain range, and the modal frequency is to avoid resonance with other parts of the vehicle.

[0086] In order to accurately judge whether the performance of the body in white after material replacement meets the design requirements, judgment criteria are configured.

[0087] Specifically, for bending stiffness and torsional stiffness, an allowable error range can be set. For example, if the deviation between the actual calculated value and the design value is within ±3%, it is considered to meet the requirements. For modal frequency, the calculated modal frequencies of each order are required to completely match the frequency range required by the design, otherwise it will cause abnormal vibration of the vehicle during driving.

[0088] This embodiment judges the performance of the body-in-white after material replacement based on the judgment conditions. If all performance indicators meet the preset design variables based on commercial vehicle performance and weight reduction target parameters, it means that the material replacement plan is feasible. If some performance indicators do not meet the design requirements, the material replacement plan is unreasonable and there are problems with the model setting. According to the analysis results, the material replacement plan and the optimization model are readjusted, and then the simulation calculation is performed. Until it meets the preset design variables based on commercial vehicle performance and weight reduction target parameters.

[0089] In an embodiment of the present invention, based on step S103, a possible embodiment is given below to illustrate its specific implementation scheme in a non-limiting manner.

[0090] As a preferred calculation method for calculating the torsional stiffness, bending stiffness, modal frequency and sensitivity of the body-in-white structural performance parameters of commercial vehicles to the thickness variables of the components in this embodiment, the following is used: The calculation formula for the torsional stiffness of the commercial vehicle body in white is:

[0091] Where: k is the torsional stiffness, N·m·(°) －1 ; T is the applied torque, N·m; D1 is the Z displacement of the left loading point of the front overhang; D2 is the Z displacement of the right loading point of the front overhang; L is the Y distance between the loading points.

[0092] The calculation formula for bending stiffness is:

[0093] Where: k2 is the bending stiffness, N / mm; F ​​is the total load of the front seat; D3 is the maximum displacement of the left longitudinal beam in the Z direction; D4 is the maximum displacement of the right longitudinal beam in the Z direction.

[0094] The formula for calculating the mode is: .

[0095] Where: K3 is the modal frequency of the system, Hz; ω is the angular velocity of the system; M is the system mass matrix.

[0096] In this embodiment, the optimization speed can be greatly improved by performing sensitivity analysis on the design variables, and the magnitude of the sensitivity analysis can reflect the degree of influence of the design variables on the performance parameters. The sensitivity analysis can clearly show the derivative of the performance parameters for each design variable, and obtain the sensitivity coefficient and the most suitable design parameters that meet your needs. The sensitivity S of the body-in-white structural performance parameters to the component thickness variation is calculated as follows:

[0097] Where: S is sensitivity; is the derivative of the objective function f(x) with respect to the initial variable xi.

[0098] By arranging the calculated sensitivity values ​​of the corresponding key variables in descending order, the design variables for each target response are analyzed. In the process of optimization design, the more data the design variable data set contains, the more computing resources are required. Therefore, designers need to select and determine the relevance ranking of the design variables in the data set to the objective function and constraints, so that they can select design variables that meet the requirements.

[0099] On the basis of the above embodiment, in order to further improve the reliability of the commercial vehicle steel-aluminum hybrid body-in-white design method provided by the above embodiment, the following is a specific implementable method. In the following embodiment, the thickness of the body-in-white sheet metal is taken as the screening data set for iteration, and the results are respectively recorded as S M , S B , S T , S MT .

[0100] Where: S M is the sensitivity of the body-in-white mass to the thickness variable; S B is the sensitivity of the body-in-white bending stiffness to the thickness variation; S T is the sensitivity of the body-in-white torsional stiffness to the thickness variation; S MT is the sensitivity of the first torsional mode of the body in white to the thickness variable.

[0101] If the mass sensitivity S of a part is a positive number, it means that as the thickness of commercial vehicle parts increases, the corresponding mass and stiffness will also increase. If it is a negative number, it means that the corresponding performance of the body in white cannot be improved simply by increasing the material thickness.

[0102] In the process of lightweighting the body in white, the relationship between constraints and objective functions is considered from different angles, and the design variables are weighed and selected.

[0103] The relative sensitivity r is: .

[0104] Where: m is mass; S is sensitivity. Relative sensitivity of torsional stiffness r t for: r t = S M / S T .

[0105] Relative sensitivity of torsional mode r mt For: mt = S M / SMT .

[0106] Relative sensitivity of bending stiffness r b For: b = S M / S B .

[0107] It can be seen that the larger the relative sensitivity value, the higher the sensitivity of the component to the objective function and the lower the sensitivity to the performance constraint. This meets the requirements of lightweight design. After submitting the calculation, the parts with the largest absolute values ​​of stiffness and modal relative sensitivity are selected as the design variables for lightweight design.

[0108] In this embodiment, a multi-objective optimization program is used, and the mathematical model for setting weight, torsion, and bending constraints is expressed as:

[0109] Where f(x) is the objective function, which can be set as a weight target, torsion target, bending target, etc.; n is the number of functions; r(x) and k(x) are the inequality constraint function and equality constraint function, respectively; p and q are the number of constraint functions, respectively; x=(x1,x2,…,x n ) is the design variable, which can be the material thickness, material yield and other design optional values; m is the number of design variables; x L and x U are the upper and lower limits of the design variables, respectively, constraining the design variables to take values ​​within the feasible range of the project. The design variable value x=(x1,x2,…,x n ) is called a feasible solution.

[0110] For example, in this embodiment, the ABAQUS component can be used in the Isight software to call the finite element model data file and the calculation result file, and the corresponding stiffness and mass can be calculated by the calculator component, and the data can be sent back to Task 1 for sampling and optimization. For example, the 10 plates with the greatest sensitivity to the three target performances of weight target, torsion target, and bending target mentioned above are selected as the optimized parameter variables, and the material thickness change is used as the design variable.

[0111] The approximate model is used to fit the ABAQUS calculation part, and the displacement of the loading point is calculated and sent to the stiffness calculator to calculate the bending and torsional stiffness and send it back. At the same time, it is sent to the mass calculator module to calculate the total mass and send it back, thus completing a calculation. In the three-dimensional rectangular coordinate system, the three optimization targets are set as coordinates, and each set of data is represented by a sample point. Then, a very intuitive target performance change trend is generated in space. The surface formed by the boundary points reached along the three target optimization directions is the Pareto frontier surface. The boundary points on the left side of the space are all optimal solutions, which together constitute the Pareto frontier surface.

[0112] This embodiment can find one or more solutions that meet the requirements by displaying the three-dimensional coordinates of multiple sets of data performance according to the required design goals and by weighing the three target performances. Finally, the data obtained in Isight is rounded to meet the actual engineering needs.

[0113] For one or more material thickness values ​​obtained after calculation and rounding, bring them into the software again to update the weight target, torsion target, and bending target. So far, the material thickness selection design based on the balance between weight target, torsion target, and bending target is completed. For one or more material thickness values ​​calculated by the software, calculate their corresponding costs respectively and select the lowest value. So far, the material thickness selection design based on the balance between weight target, torsion target, and bending target is completed.

[0114] It should be understood that the order of execution of the steps in the above embodiment does not necessarily mean 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 embodiment of the present invention.

[0115] The following is an embodiment of a commercial vehicle steel-aluminum hybrid body-in-white design system provided by an embodiment of the present disclosure. The system and the commercial vehicle steel-aluminum hybrid body-in-white design method of the above-mentioned embodiments belong to the same inventive concept. For details not fully described in the embodiment of the commercial vehicle steel-aluminum hybrid body-in-white design system, reference can be made to the above-mentioned embodiment of the commercial vehicle steel-aluminum hybrid body-in-white design method.

[0116] like Figure 5 As shown, the system includes: The data pre-definition module is used to establish a commercial vehicle body-in-white material library, a performance benchmark library, and a body component connection method library, and preset design variables based on commercial vehicle performance and weight reduction target parameters.

[0117] The target setting module is used to determine the design variables based on the performance and weight of the commercial vehicle body according to the preset body-in-white model and performance benchmark library information.

[0118] The parameter calculation module is used to calculate the torsional stiffness, bending stiffness, modal frequency and sensitivity of the body-in-white structural performance parameters of commercial vehicles to the thickness variables of components to obtain the body-in-white structural information of commercial vehicles.

[0119] The material replacement module is used to formulate material replacement of aluminum instead of steel for body-in-white parts according to structural characteristics and update the body-in-white model.

[0120] The simulation analysis module is used to simulate and analyze the body-in-white model after updating the material, and obtain the bending stiffness, torsional stiffness and modal values ​​of the body-in-white.

[0121] The parameter determination module is used to determine whether the bending stiffness, torsional stiffness and modal values ​​of the body in white meet the design data after the material is replaced.

[0122] The system of this application is based on the design variables of commercial vehicle body performance and weight, and sets constraints on the bending stiffness, torsional stiffness, modal frequency and other performance indicators of the body in white as constraints. The bending stiffness of the body in white is not less than a certain set value, the torsional stiffness is within a certain range, and the modal frequency avoids resonance with other parts of the vehicle. At the same time, constraints in manufacturing process, material properties, etc., such as the minimum thickness of parts, maximum forming angle, etc., must also be considered. It can ensure that the final design of the commercial vehicle body in white meets the design goals of performance, weight reduction and cost.

[0123] like Figure 6 As shown, the present application also provides an electronic device, including a display module 103, a memory 102, a processor 101, and a computer program stored in the memory and executable on the processor 101, wherein the processor 101 implements the steps of a commercial vehicle steel-aluminum hybrid body-in-white design method when executing the program.

[0124] In embodiments of the present invention, electronic devices include, but are not limited to, laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. Electronic devices may also represent various forms of mobile devices, such as personal digital processing, cellular phones, smart phones, wearable devices, and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely examples and are not intended to limit the implementation of the embodiments of the present application described and / or required herein.

[0125] In the embodiment of the present application, the processor 101 can be implemented by using at least one of an application-specific integrated circuit (ASIC), a programmable logic device (PLD), a field programmable gate array (FPGA), a processor, a controller, a microcontroller, a microprocessor, and an electronic unit designed to perform the functions described herein. In some cases, such an implementation can be implemented in a controller. For software implementation, implementations such as processes or functions can be implemented with separate software modules that allow execution of at least one function or operation. The software code can be implemented by a software application (or program) written in any appropriate programming language, and the software code can be stored in a memory and executed by a controller.

[0126] The display module 103 is used to display information input by the user or information provided to the user. The display module 103 may include a display panel, which may be configured in the form of a liquid crystal display (LCD), an organic light-emitting diode (OLED), etc.

[0127] The memory 102 may be used to store software programs and various data. The memory 102 may include a high-speed random access memory and may also include a non-volatile memory, such as at least one disk storage device, a flash memory device, or other volatile solid-state storage devices.

[0128] The present application also provides a storage medium, in which a program product capable of implementing the above method of the present specification is stored, and when the computer program is executed by a processor, the steps of the commercial vehicle steel-aluminum hybrid body-in-white design method are implemented. The steps of the commercial vehicle steel-aluminum hybrid body-in-white design method can be implemented in the form of a program product, which includes a program code. When the program product is run on a terminal device, the program code is used to enable the terminal device to execute the steps according to various exemplary embodiments of the present disclosure described in the above "Exemplary Method" section of the present specification.

[0129] The storage medium can adopt any combination of one or more readable media. The readable medium can be a readable signal medium or a readable storage medium. The readable storage medium can be, for example, but not limited to, a system, device or device of electricity, magnetism, light, electromagnetic, infrared, or semiconductor, or any combination of the above. More specific examples (non-exhaustive list) of readable storage media include: an electrical connection with one or more wires, a portable disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above.

[0130] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A commercial vehicle steel-aluminum hybrid body-in-white design method, characterized in that the method include: Establish a commercial vehicle body-in-white material library, performance benchmark library, and body component connection method library, and preset design variables based on commercial vehicle performance and weight reduction target parameters; Determine the design variables based on the performance and weight of the commercial vehicle body according to the preset body-in-white model and performance benchmarking library information; Calculate the torsional stiffness, bending stiffness, modal frequency and sensitivity of the body-in-white structural performance parameters to the component thickness variables to obtain the commercial vehicle body-in-white structural information; Formulate the body-in-white parts to replace steel with aluminum according to the structural characteristics, and update the body-in-white model; The body-in-white model with updated materials is simulated and analyzed to obtain the bending stiffness, torsional stiffness and modal values ​​of the body-in-white; Determine whether the bending stiffness, torsional stiffness and modal values ​​of the body in white meet the design data after the material is replaced.

2. The commercial vehicle steel-aluminum hybrid body-in-white design method according to claim 1, characterized in that: In the method, the calculation formula of the torsional stiffness of the commercial vehicle body in white is: Where: k is the torsional stiffness; T is the applied torque; D1 is the displacement of the left loading point of the front overhang based on the preset direction; D2 is the displacement of the right loading point of the front overhang based on the preset direction; L is the distance between the loading points.

3. The commercial vehicle steel-aluminum hybrid body-in-white design method according to claim 1, characterized in that: In the method, the bending stiffness is calculated as: Where: k2 is the bending stiffness; F is the total load of the front seat; D3 is the maximum displacement of the left longitudinal beam based on the preset direction; D4 is the maximum displacement of the right longitudinal beam based on the preset direction.

4. The commercial vehicle steel-aluminum hybrid body-in-white design method according to claim 1, characterized in that: In the method, the modal frequency is calculated as: ; Where: K3 is the modal frequency; ω is the angular velocity; M is the mass matrix; The sensitivity S of the body-in-white structural performance parameters to the component thickness variation is calculated as: Where: is the objective function, the derivative of f(x) with respect to the initial variable xi.

5. The commercial vehicle steel-aluminum hybrid body-in-white design method according to claim 1, characterized in that: The material replacement methods of aluminum for steel include: using steel materials for frame crossbeams, longitudinal beams, and A-pillar reinforcement plates; The exterior skin parts are made of aluminum alloy; Discrete single impact hard point is made of die-cast aluminum alloy; The threshold crossbeam adopts a grid-like staggered rib structure.

6. The commercial vehicle steel-aluminum hybrid body-in-white design method according to claim 1, characterized in that: The constraint data of the body-in-white bending stiffness loading point is set in the method; The constraint data of the left and right front overhangs and the left and right rear overhangs are SPC123456; the two seats of the commercial vehicle are loaded with 1367.1N in the preset direction respectively; Set the constraint data of the torsional stiffness loading point of the body in white; The constraint data of the left and right rear suspensions in the front torsion constraint is SPC123456; 2935.8N are loaded in the preset directions of the left and right front suspensions respectively; In the rear torsion constraint, the constraint data of the left and right front suspension and the left and right rear suspension are SPC123456, and 1584.6N are loaded in the preset directions of the left and right rear suspension respectively.

7. The commercial vehicle steel-aluminum hybrid body-in-white design method according to claim 1, characterized in that: The design data based on the performance and weight reduction target parameters of commercial vehicles is expressed as Where f(x) is the objective function; n is the number of functions; r(x) and k(x) are the inequality constraint function and equality constraint function respectively; p and q are the number of constraint functions respectively; x=(x1,x2,…,x n ) is the design variable, is the material thickness, and is the material yield design value; m is the number of design variables; x L and x U are the upper and lower limits of the design variables, respectively, constraining the range of the design variables; the design variable value x=(x1,x2,…,x n ) is called a feasible solution.

8. A commercial vehicle steel-aluminum hybrid body-in-white design system, characterized in that: The system is used to implement the commercial vehicle steel-aluminum hybrid body-in-white design method as described in any one of claims 1 to 7; The system includes: Data pre-definition module, used to establish a commercial vehicle body-in-white material library, performance benchmark library, and body component connection method library, and preset design variables based on commercial vehicle performance and weight reduction target parameters; The target setting module is used to determine the design variables based on the performance and weight of the commercial vehicle body according to the preset body-in-white model and performance benchmarking library information; The parameter calculation module is used to calculate the torsional stiffness, bending stiffness, modal frequency and sensitivity of the body-in-white structural performance parameters to the thickness variables of the components to obtain the body-in-white structural information of the commercial vehicle; Material replacement module, used to formulate material replacement of aluminum instead of steel for body-in-white parts according to structural characteristics, and update the body-in-white model; The simulation analysis module is used to simulate and analyze the body-in-white model after the material is updated to obtain the bending stiffness, torsional stiffness and modal values ​​of the body-in-white; The parameter determination module is used to determine whether the bending stiffness, torsional stiffness and modal values ​​of the body in white meet the design data after the material is replaced.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the program, the steps of the commercial vehicle steel-aluminum hybrid body-in-white design method as described in any one of claims 1 to 7 are implemented.

10. A storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the commercial vehicle steel-aluminum hybrid body-in-white design method as claimed in any one of claims 1 to 7 are implemented.

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