Design method and device for internal stiffeners of a subframe

Abstract

The application relates to the technical field of vehicle design, in particular to a design method and device for internal reinforcing ribs of a subframe, wherein the method comprises the following steps: constructing a design space of the subframe according to a blank structure of the subframe; obtaining a load working condition of the subframe and determining a topological structure of the reinforcing ribs in the subframe based on the load working condition and the design space; performing dot distribution and rib connection on the reinforcing ribs based on the topological structure to obtain an initial model of the reinforcing ribs, and performing size optimization on the initial model of the reinforcing ribs to simulate the thickness of the reinforcing ribs; performing size assignment on the reinforcing ribs in the initial model of the reinforcing ribs according to the thickness to obtain a target reinforcing rib model of the subframe; and performing performance verification on the subframe based on the target reinforcing rib model to obtain a performance verification result of the subframe. The method can realize reasonable topological layout, optimal thickness size, up-to-standard mechanical performance and significant lightweight effect of the internal reinforcing ribs of the subframe, thereby effectively avoiding the blindness of traditional experience design and improving development efficiency.

Description

Technical Field

[0001] This application relates to the field of vehicle design technology, and in particular to a design method and device for internal reinforcing ribs of a subframe. Background Technology

[0002] Steel subframes are widely used in passenger car suspension systems due to their low cost and ease of maintenance.

[0003] In related technologies, the design of traditional steel subframes usually involves designing internal reinforcing ribs for hollow subframes based on experience to obtain the initial subframe structure. The initial structure is then given to engineers for performance verification, and the verification results are fed back to designers for structural improvements.

[0004] However, the initial subframe structure designed based on experience requires more than a dozen iterations to meet performance requirements. The design cycle is long and the weight is heavy, which cannot meet the requirements of development cycle and lightweighting, and urgently needs to be improved. Summary of the Invention This application provides a design method and apparatus for internal stiffeners of a subframe. The method can determine the layout of stiffeners based on the constructed subframe design space and load condition topology, and then obtain the optimal stiffener thickness by connecting the stiffeners at points and optimizing the dimensions. After assigning values, a target stiffener model is formed, and then the performance is checked. If it passes the check, the final design model is determined. Thus, the designed internal stiffeners of the subframe meet the requirements of subframe stiffness, strength, modal performance and manufacturing process, while achieving structural lightweighting, reducing design blindness and improving development efficiency.

[0005] The first aspect of this application provides a design method for internal reinforcing ribs of a subframe, comprising: constructing a design space for the subframe based on a blank structure of the subframe; obtaining the load conditions of the subframe, and determining the topology of the reinforcing ribs in the subframe based on the load conditions and the design space; arranging and connecting the reinforcing ribs according to the topology to obtain an initial model of the reinforcing ribs, and optimizing the dimensions of the initial model of the reinforcing ribs to simulate the thickness of the reinforcing ribs; assigning dimensions to the reinforcing ribs in the initial model of the reinforcing ribs according to the thickness to obtain a target reinforcing rib model of the subframe; performing performance verification on the subframe based on the target reinforcing rib model to obtain a performance verification result of the subframe; and, in response to the performance verification result satisfying preset subframe performance conditions, using the target reinforcing rib model as a target design model.

[0006] In one embodiment of this application, the method further includes: in response to the performance verification result not meeting the preset subframe performance conditions, re-executing the subframe internal reinforcing rib design method as described above until the re-obtained performance verification result meets the preset subframe performance conditions.

[0007] In one embodiment of this application, the step of constructing the design space of the subframe based on the blank structure of the subframe includes: extracting the middle surface of the steel plate of the blank structure to divide the middle surface of the steel plate into a mesh to generate a mesh model of the blank structure; performing co-point processing on the mesh model according to the preset weld positions to generate a closed space of the subframe; and filling the closed space with a tetrahedral solid mesh to obtain the design space of the subframe.

[0008] In one embodiment of this application, determining the topology of the stiffener in the subframe based on the load conditions and the design space is characterized by comprising: setting the material properties and cross-sectional properties of the design space; applying a load to the subframe based on the load conditions, wherein the load conditions include stiffness analysis conditions, strength analysis conditions, and modal analysis conditions; setting the load condition response of the subframe, wherein the load condition response includes displacement response, weighted strain energy response, modal frequency response, and volume fraction response; setting constraints on the subframe, wherein the constraints include dimensional constraints, casting constraints, checkerboard parameter constraints, displacement constraints, volume fraction constraints, and modal frequency constraints; and analyzing the subframe based on the material properties, the cross-sectional properties, the load conditions, the load condition response, and the constraints, with the goal of minimizing the weighted strain energy response, to obtain the topology of the stiffener.

[0009] In one embodiment of this application, setting the material properties and cross-sectional properties of the design space includes: setting the material elastic modulus, material Poisson's ratio, and material density of the design space; and setting the cross-sectional properties of the design space to tetrahedral solid elements.

[0010] In one embodiment of this application, the step of arranging and connecting the reinforcing ribs based on the topology to obtain an initial model of the reinforcing ribs includes: obtaining the estimated thickness of the reinforcing ribs based on the topology, and determining the arrangement information of the reinforcing ribs based on the estimated thickness; connecting the arrangement points based on the arrangement information to obtain the initial model of the reinforcing ribs, wherein the chamfer connecting the initial model of the reinforcing ribs and the non-design space of the subframe is not less than 120°.

[0011] In one embodiment of this application, the step of dimensionally optimizing the initial model of the stiffener to simulate its thickness includes: setting the material and cross-sectional properties of the non-design space and the stiffener; applying loads to the subframe based on load conditions, wherein the load conditions include stiffness analysis conditions, strength analysis conditions, and modal analysis conditions; setting the load condition response of the subframe, wherein the load condition response includes displacement response, weighted strain energy response, modal frequency response, and mass response; setting constraints on the subframe, wherein the constraints include weighted strain energy response constraints, modal frequency response constraints, displacement response constraints, and stiffener thickness constraints; and calculating the stiffener thickness based on the material properties, cross-sectional properties, load conditions, load condition response, and constraints, with the goal of minimizing the mass response.

[0012] A second aspect of this application provides a design apparatus for internal reinforcing ribs of a subframe, comprising: a construction module for constructing a design space for the subframe based on a blank structure of the subframe; a topology module for acquiring the load conditions of the subframe and determining the topology of the reinforcing ribs in the subframe based on the load conditions and the design space; a simulation module for arranging and connecting the reinforcing ribs based on the topology to obtain an initial model of the reinforcing ribs, and optimizing the dimensions of the initial model of the reinforcing ribs to simulate the thickness of the reinforcing ribs; an assignment module for assigning dimensions to the reinforcing ribs in the initial model of the reinforcing ribs according to the thickness to obtain a target reinforcing rib model of the subframe; a verification module for performing performance verification on the subframe based on the target reinforcing rib model to obtain a performance verification result of the subframe; and a first response module for using the target reinforcing rib model as a target design model in response to the performance verification result satisfying a preset subframe performance condition.

[0013] In one embodiment of this application, the device further includes: a second response module, configured to, in response to the performance verification result not meeting the preset subframe performance conditions, re-execute the subframe internal reinforcing rib design method as described above, until the re-obtained performance verification result meets the preset subframe performance conditions.

[0014] In one embodiment of this application, the construction module includes: an extraction unit for extracting the mid-surface of the steel plate of the blank structure to perform meshing on the mid-surface of the steel plate to generate a mesh model of the blank structure; a processing unit for performing co-point processing on the mesh model according to the preset weld position to generate the closed space of the subframe; and a filling unit for filling the closed space with tetrahedral solid mesh to obtain the design space of the subframe.

[0015] In one embodiment of this application, the topology module includes: a first setting unit for setting the material properties and cross-sectional properties of the design space; a first applying unit for applying loads to the subframe based on the load conditions, wherein the load conditions include stiffness analysis conditions, strength analysis conditions, and modal analysis conditions; a second setting unit for setting the load condition response of the subframe, wherein the load condition response includes displacement response, weighted strain energy response, modal frequency response, and volume fraction response; a third setting unit for setting the constraint conditions of the subframe, wherein the constraint conditions include dimensional constraints, casting constraints, checkerboard parameter constraints, displacement constraints, volume fraction constraints, and modal frequency constraints; and a topology optimization unit for analyzing the subframe based on the material properties, the cross-sectional properties, the load conditions, the load condition response, and the constraint conditions, with the goal of minimizing the weighted strain energy response, to obtain the topology of the stiffener.

[0016] In one embodiment of this application, the first setting unit is used to: set the material elastic modulus, material Poisson's ratio and material density of the design space; and set the cross-sectional properties of the design space to tetrahedral solid elements.

[0017] In one embodiment of this application, the simulation module includes: a determining unit, configured to obtain the estimated thickness of the reinforcing rib based on the topology, and determine the layout information of the reinforcing rib according to the estimated thickness; and a generating unit, configured to connect the layout points based on the layout information to obtain an initial model of the reinforcing rib, wherein the chamfer connecting the initial model of the reinforcing rib and the non-design space of the subframe is not less than 120°.

[0018] In one embodiment of this application, the simulation module is further configured to: set the material properties and cross-sectional properties of the non-design space and the stiffener; apply loads to the subframe based on load conditions, wherein the load conditions include stiffness analysis conditions, strength analysis conditions, and modal analysis conditions; set the load condition response of the subframe, wherein the load condition response includes displacement response, weighted strain energy response, modal frequency response, and mass response; set constraints on the subframe, wherein the constraints include: weighted strain energy response constraints, modal frequency response constraints, displacement response constraints, and thickness constraints of the stiffener; and calculate the thickness of the stiffener based on the material properties, the cross-sectional properties, the load conditions, the load condition response, and the constraints, with the goal of minimizing the mass response.

[0019] A third aspect of this application provides an electronic device, including: a memory, a processor, and a computer program stored in the memory and executable on the processor. The processor executes the program to implement the design method for internal reinforcing ribs of the subframe as described in the above embodiments.

[0020] A fourth aspect of this application provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described design method for internal reinforcing ribs of the subframe.

[0021] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0022] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein: Figure 1 This is a flowchart illustrating a design method for internal reinforcing ribs of a subframe according to an embodiment of this application; Figure 2 This is a schematic diagram of a subframe blank structure according to a specific embodiment of this application; Figure 3 This is a schematic diagram of the subframe design space filling according to a specific embodiment of this application; Figure 4 This is a schematic diagram of the topology-optimized stiffener structure and its arrangement according to a specific embodiment of this application; Figure 5 This is a schematic diagram of the subframe connecting ribs according to a specific embodiment of this application; Figure 6 This is a flowchart illustrating a design method for internal reinforcing ribs of a subframe according to a specific embodiment of this application; Figure 7 This is a schematic diagram of the design device for the internal reinforcing ribs of the subframe according to an embodiment of this application; Figure 8 This is a schematic diagram of the structure of an electronic device provided according to an embodiment of this application. Detailed Implementation

[0023] The embodiments of this application are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0024] The design method and apparatus for internal reinforcing ribs of the subframe according to embodiments of this application are described below with reference to the accompanying drawings. Addressing the problem that designing the initial subframe structure based on experience cannot meet development cycle and lightweight requirements, this application provides a design method for internal reinforcing ribs of the subframe. In this method, a design space can be accurately constructed based on the subframe blank structure. A reasonable reinforcing rib layout topology is obtained by combining the actual load conditions with topology solving. Then, the initial reinforcing rib model is reconstructed by connecting the reinforcing ribs at points, and the optimal thickness of each reinforcing rib is accurately matched through size optimization. Further, the optimized thickness is assigned to form a target reinforcing rib model for the subframe, and multi-dimensional performance verification of strength, stiffness, and modal characteristics is carried out. After meeting the preset performance conditions, the final target design model is determined. This achieves a reasonable topological layout, optimal thickness, and satisfactory mechanical performance of the internal reinforcing ribs of the subframe, while also considering structural manufacturability and vehicle installation requirements. It effectively avoids the blindness of traditional experience-based design, improves the overall stiffness, strength, and anti-resonance capability of the subframe, and achieves lightweight structural design while meeting the chassis operating conditions, shortening the development cycle and reducing R&D costs.

[0025] Figure 1 This is a flowchart illustrating a design method for internal reinforcing ribs of a subframe provided in an embodiment of this application.

[0026] like Figure 1 As shown, the design method for the internal reinforcing ribs of the subframe includes the following steps: In step S101, the design space of the subframe is constructed based on the blank structure of the subframe.

[0027] The subframe of a vehicle is generally configured as a "well" shape formed by two longitudinal beams and two transverse beams. The cross-section of the longitudinal and transverse beams is generally a variable cross-section "mouth" shape formed by welding two "U"-shaped openings together. The specific blank structure of the hollow subframe can be determined based on the hard points (coordinates of the chassis mounting hard points) and the overall layout space of the vehicle. The blank structure of the subframe can be referenced. Figure 2 As shown.

[0028] In one embodiment of this application, the design space of the subframe is constructed based on the blank structure of the subframe, including: extracting the middle surface of the steel plate of the blank structure, dividing the middle surface of the steel plate into a grid to generate a grid model of the blank structure; performing co-point processing on the grid model according to the preset weld position to generate a closed space of the subframe; and filling the closed space with a tetrahedral solid grid to obtain the design space of the subframe.

[0029] Design space filling is the preliminary modeling preparation for topology optimization—first, the outer shell skeleton of the subframe (non-design space) is made, and then the hollow area inside the shell (design space) is filled with solid mesh, finally forming a dual-region model with a fixed outer shell and an optimizable interior, laying the foundation for subsequent optimization of the reinforcing rib layout only in the internal design space area.

[0030] Specifically, this embodiment can divide the construction of the design space into two steps: Step 1: Create a fixed outer shell (outside the designed space area). The specific steps are as follows: Import the drawn blank structure into OptiStruct software. OptiStruct is a general-purpose finite element structural solver and structural optimization simulation software. Because the subframe shell is made of thin steel plate, the software does not need to model it as solid. Instead, it extracts the neutral mid-surface of the steel plate (simply put, the face in the middle of the steel plate thickness) and divides this mid-surface into small meshes (i.e., mesh generation). At the same time, the original welding positions are processed in the software to make the mesh nodes of the two welded parts coincide. After this processing, a complete and closed hollow frame is formed in the software (completely consistent with the actual subframe shell). This shell frame cannot be modified in subsequent optimization (it must be kept as is), so it is recorded as non-design space.

[0031] Step 2: Fill the internal optimizable space (design space area), such as Figure 3 As shown, the specific operation is as follows: Using the closed framework of the non-design space created in the first step, the software automatically generates tetrahedral solid meshes within the hollow interior (such as the blank area in the middle of the grid frame or the hollow area inside the longitudinal and transverse beams) (completely filling the hollow areas, like filling a box with building blocks). The filled internal solid mesh area is the area to be optimized later. The software will modify materials and generate reinforcing ribs in this area. This modifiable and optimizable internal area is called the optimizable design space.

[0032] In step S102, the load conditions of the subframe are obtained, and the topology of the stiffeners in the subframe is determined based on the load conditions and design space.

[0033] The topology of reinforcing ribs refers to where the reinforcing ribs are arranged in the design space, how many there are, how they run, how they connect with each other, their branching and trend patterns. It does not concern the width or thickness of the ribs, but only their layout and force transmission path.

[0034] In one embodiment of this application, the topology of the stiffener in the subframe is determined based on load conditions and design space, including: setting the material properties and cross-sectional properties of the design space; applying loads to the subframe based on load conditions, wherein the load conditions include stiffness analysis conditions, strength analysis conditions, and modal analysis conditions; setting the load condition response of the subframe, wherein the load condition response includes displacement response, weighted strain energy response, modal frequency response, and volume fraction response; setting constraints on the subframe, wherein the constraints include dimensional constraints, casting constraints, checkerboard parameter constraints, displacement constraints, volume fraction constraints, and modal frequency constraints; and analyzing the subframe based on material properties, cross-sectional properties, load conditions, load condition response, and constraints, with the goal of minimizing the weighted strain energy response, to obtain the topology of the stiffener.

[0035] Specifically, by using topology optimization to find the force transmission path of the subframe design space under different working conditions and to preliminarily determine the arrangement of stiffeners, the following steps can be taken: 1. Material and section property settings: Set the material and cross-sectional properties of the structural mesh in both the design space and the non-design space. The material properties include the elastic modulus, Poisson's ratio, and density. For example, the elastic modulus E = 210000 MPa, the Poisson's ratio v = 0.3, and the density ρ = 7900 kg / m3. The cross-sectional properties of the non-design space are set to plate and shell elements with a thickness of 2.5 mm, while the cross-sectional properties of the design space are set to tetrahedral solid elements.

[0036] 2. Establish load conditions: Establish stiffness, strength and modal load analysis conditions, and establish load and constraint conditions according to different conditions.

[0037] Among them, the stiffness analysis working condition can be set as follows: the connection point between the subframe and the body is fully constrained, and the force F = 1000N is applied along the two-force direction of the control arm at the connection point between the control arm and the subframe. The strength analysis working condition can be set as follows: the connection point between the subframe and the body is fully constrained, and the load decomposed according to the actual working condition of the subframe is applied to the connection point between the control arm and the subframe. The modal analysis working condition can be set as: free mode (i.e. no constraints or loads are applied), and the first 3 modes are calculated. The first 3 modes refer to the first three natural vibration modes and their corresponding natural frequencies in the structure's natural vibration characteristics, arranged in order of frequency from low to high. The low-order modes are easily excited by external excitation and are the main control objects for the subframe modal verification. Their minimum frequency is 1 Hz and their maximum frequency is 1000 Hz.

[0038] 3. Optimize parameter settings: Based on the design space of the subframe, minimum and maximum member size constraints are introduced to control the optimized stiffeners so that they are neither too thin nor too wide, ensuring that they can be stamped / welded later, while avoiding extremely unreasonable dimensions. The checkerboard pattern is adjusted to the maximum parameter of 1. In topology optimization, scattered, fragmented, and discontinuous small pieces of material (checkerboard phenomenon) are easily generated. The checkerboard suppression parameter is set to the maximum value of 1 to force the optimized stiffeners to be continuous, regular, and free of scattered fragments. The casting constraint is set to unidirectional draft in the Z-direction of the whole vehicle, so that all generated stiffener structures can be smoothly demolded along the vertical Z-direction of the whole vehicle without undercuts or hooks, thus conforming to the stamping and welding forming process. The optimization results can be implemented in engineering, avoiding structures that cannot be manufactured. Displacement response for stiffness analysis, weighted strain energy response, modal frequency response, and volume fraction response for strength analysis under various working conditions are established. The optimization objective is set as minimizing the weighted strain energy, and the constraints are displacement response, volume fraction response, and modal frequency response.

[0039] The displacement constraint can be set as follows: the displacement of the connection point between the control arm and the subframe along the two-force member direction of the control arm is <0.3mm; The volume fraction constraint can be set as: volume fraction < 30%; The modal frequency constraint can be set as follows: first-order torsional frequency > 200 Hz.

[0040] 4. Use Optistruct software to perform topology calculations to obtain the topology optimization structure with stiffeners, such as... Figure 4 As shown, the optimized topology results were geometrically smoothed, mesh regularized, and performance recalculated using the POST post-processing module, OSSmooth smoothing function, and FEAreanalysis function built into the OptiStruct software. This generated a continuous and regular stiffener mesh model, which was finally exported and saved as a fem format finite element model file for subsequent reinforcement placement and dimensional optimization.

[0041] In step S103, the reinforcing ribs are arranged and connected based on the topology to obtain an initial model of the reinforcing ribs, and the size of the initial model of the reinforcing ribs is optimized to simulate the thickness of the reinforcing ribs.

[0042] In one embodiment of this application, the reinforcing ribs are arranged and connected based on the topology to obtain an initial model of the reinforcing ribs, including: obtaining the estimated thickness of the reinforcing ribs based on the topology, and determining the arrangement information of the reinforcing ribs based on the estimated thickness; connecting the arrangement points based on the arrangement information to obtain an initial model of the reinforcing ribs, wherein the chamfer of the connection between the initial model of the reinforcing ribs and the non-design space of the subframe is not less than 120°.

[0043] Specifically, this embodiment determines the distribution of reinforcing ribs in the subframe based on a topology-optimized structural diagram. The reinforcing ribs can be distributed in a continuous or localized manner, and they may intersect or separate. Simply replace the original reinforcing ribs with steel plates following the rib's direction. Considering the varying sizes of the reinforcing ribs after topology optimization, and the commonly used steel plate thickness of 1mm-3mm, larger reinforcing ribs require replacement with multiple steel plates. Therefore, to restore the reinforcing rib size and direction as accurately as possible, points need to be placed on the topologically optimized reinforcing ribs. Then, these points are sequentially connected according to the reinforcing rib's direction to replace the original reinforcing ribs. The topology-optimized reinforcing rib structure and point placement are as follows: Figure 4 As shown.

[0044] For example, in this embodiment, the reinforcing ribs can be arranged according to the following strategy: Thickness principle: ① The thickness of the reinforcing rib is less than 6mm, and one point is placed at the center of the structure; ②6mm < stiffener thickness < 12mm, with 1 point at each end, for a total of 2 points; ③ Three points are evenly distributed with a thickness of 12mm < stiffener thickness < 18mm.

[0045] Shape trend principle: Each reinforcing rib has a different shape and trend. When placing points according to the shape and trend direction, it is necessary to basically depict the trend of the reinforcing rib.

[0046] Furthermore, such as Figure 5 As shown, after the placement of points is completed, reinforcement can be added based on the placement points. Reinforcement is the connection of the placement points with shell elements, and the replacement of the topology with shell elements as stiffeners. The following principles should be followed for reinforcement: 1. The direction of the reinforcement connected by points must be smooth and without sharp points to prevent stress concentration during strength performance verification; 2. When stiffeners are connected to non-designed spaces, there must be a chamfer, with a chamfer of at least 120°, to prevent stress concentration.

[0047] After the reinforcement points and connections are completed, an initial model of the stiffeners for dimensional optimization is obtained, such as... Figure 5 As shown.

[0048] Furthermore, in one embodiment of this application, the initial model of the stiffener is dimensionally optimized to simulate the thickness of the stiffener, including: setting the material and cross-sectional properties of the non-design space and the stiffener; applying loads to the subframe based on load conditions, wherein the load conditions include stiffness analysis conditions, strength analysis conditions, and modal analysis conditions; setting the load condition response of the subframe, wherein the load condition response includes displacement response, weighted strain energy response, modal frequency response, and mass response; setting constraints on the subframe, wherein the constraints include: weighted strain energy response constraints, modal frequency response constraints, displacement response constraints, and stiffener thickness constraints; and calculating the thickness of the stiffener based on the material properties, cross-sectional properties, load conditions, load condition response, and constraints, with the goal of minimizing the mass response.

[0049] Specifically, after the reinforcement points and connections are completed, the dimensions of each reinforcement rib can be further optimized to meet the stiffness, strength, and modal requirements of the subframe. Dimensional optimization can be divided into the following steps: 1. Material and section property settings: The material properties and cross-sectional properties of the non-design space and the stiffeners of the subframe are assigned respectively. The material properties can be set as follows: elastic modulus E=210000MPa, Poisson's ratio v=0.3, density ρ=7800kg / m3; the cross-sectional properties of the non-design space and the design space are set as plate and shell elements.

[0050] 2. Load condition settings: Establish strength and durability conditions, stiffness conditions and modal conditions. Among them, the stiffness analysis condition can be set as follows: the connection point between the subframe and the body is fully constrained, and the force F = 1000N is applied along the two-force direction of the control arm at the connection point between the control arm and the subframe. The strength analysis working condition can be set as follows: the connection point between the subframe and the body is fully constrained, and the load decomposed according to the actual working condition of the subframe is applied to the connection point between the control arm and the subframe. The modal analysis conditions can be set as follows: free mode, calculate the first 3 modes, minimum frequency is 1 Hz, maximum frequency is 1000 Hz.

[0051] 3. Variable, response, constraint, and goal setting: The thickness of the stiffener is used as a variable, the base thickness is 1mm, and the thickness varies from 1mm to 3mm. Four responses are established: stress (weighted strain energy), frequency, displacement, and mass response. The upper limits of the stress, frequency, and displacement responses are constrained, with the goal of minimizing the mass.

[0052] Among them, the stress response constraint can be set as follows: the stress under the strength analysis condition is less than the material strength limit of 600MPa; the modal frequency constraint can be set as follows: the first torsional frequency is greater than 200Hz; the displacement constraint can be set as follows: the displacement of the connection point between the control arm and the subframe along the two-force member direction of the control arm is less than 0.3mm.

[0053] After setting the above material properties, section properties, load conditions, working condition response and constraint conditions, the size optimization calculation of the stiffener is performed with the minimum mass response as the optimization objective, so as to obtain the thickness of each stiffener.

[0054] In step S104, the dimensions of the reinforcing ribs in the initial model of the reinforcing ribs are assigned according to the thickness to obtain the target reinforcing rib model of the subframe.

[0055] In step S105, the subframe is subjected to performance verification based on the target stiffener model to obtain the performance verification results of the subframe.

[0056] Specifically, the optimal thickness obtained from the dimensional optimization solution is assigned to each stiffener, and the overall subframe structure is sequentially checked for strength, stiffness, and modal performance to verify whether the structural stress, displacement, and natural frequency meet the design constraints. If the performance verification results meet the preset subframe performance conditions, the target stiffener model is used as the target design model. If the performance verification results do not meet the preset subframe performance conditions, the stiffeners that have completed dimensional optimization are moved to the non-design space, and the above design method for the internal stiffeners of the subframe is repeated until the re-obtained performance verification results meet the preset subframe performance conditions. The dimensional data of the stiffeners is then locked. The subframe performance conditions can be set according to the actual application scenario and are not specifically limited here.

[0057] Experiments have verified that by using finite element optimization technology to design a hollow steel subframe, the traditional development cycle of 6-8 weeks can be shortened to 2-3 weeks, while the weight can be reduced by 20%-30%.

[0058] In summary, as Figure 6 As shown, the design method for the internal reinforcing ribs of the subframe proposed in the above embodiments can be summarized as follows: Step S601: Determine the design space for the internal reinforcing ribs of the subframe and fill the design space with tetrahedral solid units; Step S602: Use topology optimization to find the force transmission path of the subframe design space under different working conditions, and simulate the topology optimization structure of the stiffener; Step S603: Place points on the reinforcing ribs after the topology is updated, and then connect the points sequentially according to the trend of the reinforcing ribs to replace the original reinforcing ribs; Step S604: After the reinforcement points and connecting ribs are completed, the dimensions of each rib are optimized to meet the requirements of stiffness, strength and modal properties, and the thickness of each rib is calculated. Step S605: Assign the optimized thickness to each stiffener and perform strength, stiffness and modal checks respectively. If the check results meet the performance requirements, proceed to step S606 to lock the stiffener parameter data. Otherwise, classify the optimized stiffener into the non-design space of the subframe and start from step S601 again.

[0059] According to the design method for internal reinforcing ribs of the subframe proposed in this application, the design space can be accurately constructed based on the subframe blank structure. A reasonable reinforcing rib layout topology is obtained by combining the actual load conditions with topological solutions. Then, the initial model of the reinforcing ribs is reconstructed through point-connection of ribs, and the optimal thickness of each reinforcing rib is precisely matched through dimensional optimization. Further, the optimized thickness is assigned to form a target reinforcing rib model for the subframe, and multi-dimensional performance verification of strength, stiffness, and modal characteristics is carried out. After meeting the preset performance conditions, the final target design model is determined. This method can achieve a reasonable internal reinforcing rib topology layout, optimal thickness, and satisfactory mechanical performance with significant lightweighting effects. It also considers structural manufacturability and vehicle installation requirements, effectively avoiding the blind spots of traditional experience-based design, improving the overall stiffness, strength, and anti-resonance capability of the subframe, and achieving lightweight structural design while meeting the chassis operating conditions, shortening the development cycle and reducing R&D costs.

[0060] Next, refer to the appendix. Figure 7 This application describes a design device for internal reinforcing ribs of a subframe according to an embodiment of the present application.

[0061] Figure 7 This is a block diagram of the design device for the internal reinforcing ribs of the subframe according to an embodiment of this application.

[0062] like Figure 7 As shown, the design device 10 for the internal reinforcing ribs of the subframe includes: a construction module 100, a topology module 200, a simulation module 300, an assignment module 400, a verification module 500, and a first response module 600.

[0063] The construction module 100 is used to construct the design space of the subframe based on the blank structure of the subframe.

[0064] The topology module 200 is used to obtain the load conditions of the subframe and, based on the load conditions and design space, determine the topology of the stiffeners in the subframe.

[0065] The simulation module 300 is used to arrange and connect the stiffeners based on the topology to obtain the initial model of the stiffeners, and to optimize the size of the initial model of the stiffeners to simulate the thickness of the stiffeners.

[0066] The assignment module 400 is used to assign dimensions to the reinforcing ribs in the initial model of the reinforcing ribs according to the thickness, so as to obtain the target reinforcing rib model of the subframe.

[0067] The verification module 500 is used to perform performance verification on the subframe based on the target stiffener model to obtain the performance verification results of the subframe.

[0068] The first response module 600 is used to respond to the performance verification result meeting the preset subframe performance conditions by using the target stiffener model as the target design model.

[0069] In one embodiment of this application, the subframe internal reinforcing rib design device 10 further includes: a second response module, which is used to re-execute the subframe internal reinforcing rib design method as described above in response to the performance verification result not meeting the preset subframe performance conditions, until the re-obtained performance verification result meets the preset subframe performance conditions.

[0070] In one embodiment of this application, the construction module 100 includes: an extraction unit, a processing unit, and a filling unit; wherein, the extraction unit is used to extract the middle surface of the steel plate of the blank structure, so as to perform mesh division on the middle surface of the steel plate to generate a mesh model of the blank structure; the processing unit is used to perform co-point processing on the mesh model according to the preset weld position to generate the closed space of the subframe; the filling unit is used to fill the closed space with tetrahedral solid mesh to obtain the design space of the subframe.

[0071] In one embodiment of this application, the topology module 200 includes: a first setting unit, an application unit, a second setting unit, a third setting unit, and a topology optimization unit; wherein, the first setting unit is used to set the material properties and cross-sectional properties of the design space; the application unit is used to apply loads to the subframe based on load conditions, wherein the load conditions include stiffness analysis conditions, strength analysis conditions, and modal analysis conditions; the second setting unit is used to set the load condition response of the subframe, wherein the load condition response includes displacement response, weighted strain energy response, modal frequency response, and volume fraction response; the third setting unit is used to set the constraint conditions of the subframe, wherein the constraint conditions include dimensional constraints, casting constraints, checkerboard parameter constraints, displacement constraints, volume fraction constraints, and modal frequency constraints; the topology optimization unit is used to analyze the subframe based on material properties, cross-sectional properties, load conditions, load condition response, and constraint conditions, with the goal of minimizing the weighted strain energy response, to obtain the topology structure of the stiffeners.

[0072] In one embodiment of this application, the first setting unit is used to set the material elastic modulus, material Poisson's ratio and material density of the design space; and to set the cross-sectional properties of the design space as tetrahedral solid elements.

[0073] In one embodiment of this application, the simulation module 300 includes: a determination unit and a generation unit; wherein, the determination unit is used to obtain the estimated thickness of the reinforcing rib based on the topology, and determine the layout information of the reinforcing rib according to the estimated thickness; the generation unit is used to connect the layout points based on the layout information to obtain an initial model of the reinforcing rib, wherein the chamfer of the connection between the initial model of the reinforcing rib and the non-design space of the subframe is not less than 120°.

[0074] In one embodiment of this application, the simulation module 300 is further configured to set the material and section properties of the non-design space and the stiffeners; apply loads to the subframe based on load conditions, wherein the load conditions include stiffness analysis conditions, strength analysis conditions, and modal analysis conditions; set the load condition response of the subframe, wherein the load condition response includes displacement response, weighted strain energy response, modal frequency response, and mass response; set constraints on the subframe, wherein the constraints include: weighted strain energy response constraints, modal frequency response constraints, displacement response constraints, and stiffener thickness constraints; and calculate the thickness of the stiffeners based on the material properties, section properties, load conditions, load condition response, and constraints, with the goal of minimizing the mass response.

[0075] It should be noted that the foregoing explanation of the design method embodiment for the internal reinforcing ribs of the subframe also applies to the design device for the internal reinforcing ribs of the subframe in this embodiment, and will not be repeated here.

[0076] The subframe internal stiffener design device proposed in this application can accurately construct the design space based on the subframe blank structure, obtain a reasonable stiffener layout topology by combining the actual load conditions with topology solving, and then reconstruct the initial stiffener model by connecting the stiffeners at the points. After dimensional optimization, the optimal thickness of each stiffener is precisely matched. Further, the optimized thickness is assigned to form the subframe target stiffener model, and multi-dimensional performance verification of strength, stiffness, and modal characteristics is carried out. After meeting the preset performance conditions, the final target design model is determined. This method can achieve a reasonable subframe internal stiffener topology layout, optimal thickness, satisfactory mechanical performance, and significant lightweight effect. It also considers structural manufacturability and vehicle installation requirements, effectively avoiding the blind spots of traditional experience-based design, improving the overall stiffness, strength, and anti-resonance capability of the subframe, and achieving lightweight structural design while meeting the chassis operating conditions, shortening the development cycle and reducing R&D costs.

[0077] Figure 8 A schematic diagram of the structure of an electronic device provided in an embodiment of this application. The electronic device may include: The memory 801, the processor 802, and the computer program stored on the memory 801 and capable of running on the processor 802.

[0078] When the processor 802 executes the program, it implements the design method for the internal reinforcing ribs of the subframe provided in the above embodiments.

[0079] Furthermore, electronic devices also include: Communication interface 803 is used for communication between memory 801 and processor 802.

[0080] The memory 801 is used to store computer programs that can run on the processor 802.

[0081] The memory 801 may include high-speed RAM memory, and may also include non-volatile memory, such as at least one disk storage device.

[0082] If the memory 801, processor 802, and communication interface 803 are implemented independently, then the communication interface 803, memory 801, and processor 802 can be interconnected via a bus to complete communication between them. The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. Buses can be categorized into address buses, data buses, control buses, etc. For ease of representation, Figure 8 The bus is represented by a single thick line, but this does not mean that there is only one bus or one type of bus.

[0083] Optionally, in a specific implementation, if the memory 801, processor 802, and communication interface 803 are integrated on a single chip, then the memory 801, processor 802, and communication interface 803 can communicate with each other through an internal interface.

[0084] The processor 802 may be a central processing unit (CPU), an application specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of this application.

[0085] This application also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described design method for internal reinforcing ribs of the subframe.

[0086] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0087] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "N" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0088] Any process or method described in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or N executable instructions for implementing custom logic functions or processes, and the scope of the preferred embodiments of this application includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functions involved, as should be understood by those skilled in the art to which embodiments of this application pertain.

[0089] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include: an electrical connection having one or more wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). In addition, computer-readable media can even be paper or other suitable media on which programs can be printed, because programs can be obtained electronically by optically scanning paper or other media, then editing, interpreting or otherwise processing them as necessary, and then storing them in computer memory.

[0090] It should be understood that the various parts of this application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, the N steps or methods can be implemented using software or firmware stored in memory and executed by a suitable instruction execution system. If implemented in hardware, as in another embodiment, it can be implemented using any one or more of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0091] Those skilled in the art will understand that all or part of the steps of the methods described in the above embodiments can be implemented by a program instructing related hardware, and the program can be stored in a computer-readable storage medium. When executed, the program includes one or a combination of the steps of the method embodiments.

[0092] Furthermore, the functional units in the various embodiments of this application can be integrated into a processing module, or each unit can exist physically separately, or two or more units can be integrated into a module. The integrated module can be implemented in hardware or as a software functional module. If the integrated module is implemented as a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium.

[0093] The storage medium mentioned above can be a read-only memory, a disk, or an optical disk, etc. Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of this application.

Claims

1. A design method for internal reinforcing ribs of a subframe, characterized in that, include: The design space of the subframe is constructed based on the blank structure of the subframe; Obtain the load conditions of the subframe, and determine the topology of the stiffeners in the subframe based on the load conditions and the design space; Based on the topology, the reinforcing ribs are arranged and connected to obtain an initial model of the reinforcing ribs, and the size of the initial model of the reinforcing ribs is optimized to simulate the thickness of the reinforcing ribs. The dimensions of the reinforcing ribs in the initial model of the reinforcing ribs are assigned according to the thickness to obtain the target reinforcing rib model of the subframe; The performance of the subframe is verified based on the target stiffener model to obtain the performance verification result of the subframe; In response to the performance verification result meeting the preset subframe performance conditions, the target stiffener model is used as the target design model.

2. The method according to claim 1, characterized in that, Also includes: In response to the performance verification result not meeting the preset subframe performance conditions, the design method of the internal reinforcing rib of the subframe as described in claim 1 is re-executed until the performance verification result obtained again meets the preset subframe performance conditions.

3. The method according to claim 1, characterized in that, The process of constructing the design space for the subframe based on its blank structure includes: The mid-surface of the steel plate of the blank structure is extracted, and the mid-surface of the steel plate is meshed to generate a mesh model of the blank structure; The mesh model is processed to achieve common points based on the preset weld positions in order to generate the closed space of the subframe. The enclosed space is filled with a tetrahedral solid mesh to obtain the design space of the subframe.

4. The method according to claim 1, characterized in that, The method for determining the topology of the reinforcing ribs in the subframe based on the load conditions and the design space is characterized by including: Set the material properties and section properties of the design space; The subframe is subjected to loads based on the load conditions, wherein the load conditions include stiffness analysis conditions, strength analysis conditions, and modal analysis conditions. The operating condition response of the subframe is set, wherein the operating condition response includes displacement response, weighted strain energy response, modal frequency response and volume fraction response; The constraints of the subframe are set, including dimensional constraints, casting constraints, checkerboard parameter constraints, displacement constraints, volume fraction constraints, and modal frequency constraints. Based on the material properties, cross-sectional properties, load conditions, load response, and constraints, the subframe is analyzed with the goal of minimizing the weighted strain energy response to obtain the topology of the stiffener.

5. The method according to claim 4, characterized in that, The setting of the material properties and cross-sectional properties of the design space includes: The material elastic modulus, Poisson's ratio, and density of the design space are set. The cross-sectional properties of the design space are set to tetrahedral solid elements.

6. The method according to claim 1, characterized in that, The step of arranging and connecting the stiffeners based on the topology to obtain an initial model of the stiffeners includes: The estimated thickness of the reinforcing rib is obtained based on the topology, and the layout information of the reinforcing rib is determined according to the estimated thickness. Based on the layout information, the layout points are connected to obtain the initial model of the reinforcing rib, wherein the chamfer connecting the initial model of the reinforcing rib and the non-design space of the subframe is not less than 120°.

7. The method according to claim 6, characterized in that, The step of optimizing the dimensions of the initial model of the reinforcing rib to simulate the thickness of the reinforcing rib includes: Set the material properties and section properties of the non-design space and the stiffener; The subframe is subjected to loads based on load conditions, wherein the load conditions include stiffness analysis conditions, strength analysis conditions, and modal analysis conditions. The operating condition response of the subframe is set, wherein the operating condition response includes displacement response, weighted strain energy response, modal frequency response and mass response; The constraints of the subframe are set, including: weighted strain energy response constraints, modal frequency response constraints, displacement response constraints, and thickness constraints of the stiffeners. Based on the material properties, the cross-sectional properties, the load conditions, the load response, and the constraints, the thickness of the stiffener is calculated with the goal of minimizing the mass response.

8. A design device for internal reinforcing ribs of a subframe, characterized in that, include: A construction module is used to construct the design space of the subframe based on the blank structure of the subframe; The topology module is used to obtain the load conditions of the subframe and, based on the load conditions and the design space, determine the topology of the stiffeners in the subframe. The simulation module is used to arrange and connect the stiffeners based on the topology to obtain an initial model of the stiffeners, and to optimize the size of the initial model of the stiffeners to simulate the thickness of the stiffeners. The assignment module is used to assign dimensions to the reinforcing ribs in the initial model of the reinforcing ribs according to the thickness, so as to obtain the target reinforcing rib model of the subframe; The verification module is used to perform performance verification on the subframe based on the target stiffener model, so as to obtain the performance verification result of the subframe; The design module is used to take the target stiffener model as the target design model in response to the performance verification result meeting the preset subframe performance conditions.

9. An electronic device, characterized in that, include: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the design method for the internal reinforcing ribs of the subframe as described in any one of claims 1-7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, The program is executed by the processor to implement the design method for the internal reinforcing ribs of the subframe as described in any one of claims 1-7.

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