Wheel spoke weight reduction nest design method based on multi-working-condition topological optimization

Abstract

The invention relates to the field of spoke weight reduction nest design, in particular to a wheel spoke weight reduction nest design method based on multi-working-condition topological optimization, and the method comprises the steps: obtaining the sizes of a plurality of spoke back cavity weight reduction nests, obtaining the thickness ratio interval of the spoke and the spoke before the weight reduction nests are dug, deleting the original weight reduction nest area of a wheel, and obtaining the weight reduction nest size of the spoke; filling a plane to form a new closed space, taking an intermediate value of a proportion interval, dividing a wheel spoke back cavity weight reduction nest to obtain a wheel lightweight basic model, performing finite element analysis, establishing an optimization model, obtaining a strain energy result and an iterative stiffness curve, and constructing a spoke weight reduction nest multi-working-condition comprehensive evaluation function by adopting a compromise programming method. Establishing a spoke weight loss nest multi-working-condition topological optimization finite element model; and finally, carrying out bending fatigue and impact finite element analysis on the geometrically reconstructed wheel to verify the performance of the wheel. Therefore, high-performance, light-weight and high-efficiency wheel spoke weight reduction nest optimization design can be obtained.

Description

Technical Field

[0001] The invention relates to the field of wheel spoke weight reduction cavity design, and in particular to a wheel spoke weight reduction cavity design method based on multi-operating condition topology optimization. Background Art

[0002] As national environmental protection standards continue to upgrade, the automotive industry is being pushed toward energy conservation, emission reduction and lightweight design. Companies that use lightweight materials and high-tech processes will be more competitive. As the only medium for the vehicle to contact the ground, the wheels bear the weight of the entire vehicle and are the key to ensuring vehicle handling stability and driving smoothness. On the basis of ensuring that the wheel performance meets the requirements of the "GB36581-2018 Automobile Wheel Safety Performance Requirements and Test Methods" standard, in order to achieve lightweight, high efficiency and low cost of the wheels, it is necessary to perform multi-condition topological optimization of the wheels.

[0003] In the multi-condition topology optimization of wheel spokes, traditional multi-condition topology optimization methods mostly use linear weighted methods to transform multi-condition problems into single-objective problems for solution, but for non-convex optimization problems, it is not possible to ensure that all Pareto optimal solutions are obtained. In addition, the existing spoke design method of filling the entire topological space of the wheel spoke with entities will change the original spoke front shape design of the wheel. Summary of the invention

[0004] The purpose of the present invention is to solve the problem in the prior art that it is impossible to obtain all Pareto optimal solutions during the multi-condition topology optimization of wheel spokes, and to propose a wheel spoke weight reduction dimple design method.

[0005] A wheel spoke weight reduction dimple design method based on multi-operating condition topology optimization of the present invention comprises the following steps: Step 1: Obtain the dimensions of multiple existing wheel spoke back cavity weight reduction recesses to obtain the ratio of the actual spoke thickness to the spoke thickness before the spoke back cavity weight reduction recesses are dug; Step 2: Obtain the wheel geometry model to be optimized, delete the original weight-reducing dimple area, fill the plane to form a new closed space, and form a new solid geometry model; Step 3: According to the proportion interval determined in step 1, take the middle value, segment the wheel spoke back cavity weight reduction dimple design area, and divide the meshes for the wheel and the weight reduction dimple respectively to obtain the wheel lightweight finite element model; Step 4: Establish a static model of the wheel 13° impact condition and a static model of the bending fatigue condition, and perform finite element analysis on them to obtain their respective strain energy results; Step 5: Establish the topology optimization model of the wheel 13° impact condition and the topology optimization model of the bending fatigue condition respectively, and obtain their respective iterative stiffness curves; Step 6: Based on the strain energy results in step 4 and the maximum and minimum flexibility values ​​of the iterative stiffness curve extracted in step 5, a compromise programming method is used to obtain a multi-condition comprehensive evaluation function of the spoke weight reduction pocket; Step 7: Establish a multi-condition topology optimization model for the wheel through the multi-condition comprehensive evaluation function of the spoke weight-reducing pockets, and analyze and obtain the multi-condition topology optimization results; Step 8: Perform geometric reconstruction based on the topology optimization results and establish a new wheel model; Step nine: Perform static finite element analysis of the 13° impact condition and static finite element analysis of bending fatigue on the new wheel model respectively to verify the performance of the new wheel under the 13° impact condition and bending fatigue condition. If the stress results meet the criteria of the wheel manufacturer under the above two conditions, the final spoke back cavity weight reduction dimple structure design is obtained; otherwise, modify the topology optimization parameters and return to step five for re-optimization.

[0006] As a further preferred solution, step one includes: importing software to measure the dimensions of the spoke back cavity weight reduction recesses of multiple existing wheels based on the wheel manufacturer's design data model; determining the range of the actual spoke thickness and the spoke thickness before the spoke back cavity weight reduction recesses are dug out in combination with the factory's actual casting process design experience, to obtain the design range of the spoke back cavity weight reduction recesses.

[0007] As a further preferred solution, step two includes: obtaining the wheel geometry model, using Hypermesh software to clean up the model geometry, deleting the geometric entities and retaining the outer surface, deleting the original weight-reducing dimple modeling surface, filling the plane to form a new closed space and generating a new entity.

[0008] As a further preferred solution, step four includes: establishing a static model of the wheel 13° impact condition and a static model of the bending fatigue condition, respectively, with a grid unit size of 5 mm and a unit type of second-order unit, performing static analysis, and obtaining strain energy results.

[0009] As a further preferred solution, in step four, the static model of the wheel 13° impact condition is to connect the wheel impact surface to the center point of the surface with a rigid connection RBE2, and connect the wheel bolt hole to the center point of the wheel flange surface with a rigid connection RBE2, thereby constraining its six degrees of freedom; the static model of the bending fatigue condition uses a rigid connection RBE2 to simulate the bolt connection between the loading axis and the wheel mounting surface, thereby constraining all degrees of freedom on the nodes at the inner outer edge of the rim.

[0010] As a further preferred solution, the volume fraction response upper limit parameters of the 13° impact condition topology optimization model and the bending fatigue condition topology optimization model in step five, and the wheel multi-condition topology optimization model in step seven are all set to 30%~50%.

[0011] As a further preferred solution, the load and boundary conditions of the two single-condition topology optimization models in step five are the same as those of the two single-condition static models in step four. The weight reduction nest is set as the design area, and size constraints, stress constraints and draft constraints are added. The unit density is used as the design variable, the volume fraction response is used as the constraint condition, and the minimum flexibility response is used as the objective function. OptiStruct is used as the optimization design software.

[0012] As a further preferred solution, step eight includes: using OSSmooth to geometrically reconstruct the topology optimization results of multiple working conditions and establish a new wheel model.

[0013] Beneficial effects: The present invention adopts a multi-condition topology optimization method for design by comprehensively considering the stress conditions of the wheel under 13° impact conditions and bending fatigue conditions. Compared with the traditional multi-condition optimization method which mostly adopts the linear weighted method, it is easy to cause the non-convex optimization problem to be unable to obtain all Pareto optimal solutions. The present invention adopts the compromise programming method to construct a multi-condition comprehensive evaluation function, which can better balance the optimization goals under different conditions and ensure a better design scheme. Through topology optimization, the present invention can effectively reduce the weight of the wheel while ensuring the performance of the wheel, realize lightweight design, and meet the trend of energy conservation and emission reduction in the automotive industry. The traditional spoke design method usually fills the entire spoke topology space with entities, which will change the original spoke front shape design of the wheel. The present invention retains the original front shape of the wheel by optimizing the design of only the spoke back cavity weight reduction dimples, ensuring that the appearance design of the wheel is not affected.

[0014] The present invention provides a complete set of optimization design processes, from obtaining the wheel spoke shape, deleting the original weight reduction dimple shape, dividing the weight reduction dimple range, performing finite element analysis, topological optimization to the final geometric reconstruction and performance verification, the steps are clear and efficient. Through this process, designers can quickly obtain a wheel spoke weight reduction dimple design that meets performance requirements, thereby improving design efficiency. The method of the present invention is not only applicable to the design of spoke weight reduction dimples for passenger car wheels, but can also be extended to other types of wheel designs, and has wide applicability.

[0015] In summary, the present invention provides a high-performance, lightweight and efficient wheel spoke weight reduction groove design method through multi-working condition topology optimization, lightweight design and efficient optimization process, which has significant technical advantages and application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the overall process of the present invention; Figure 2 is a cross-sectional view of a spoke in an embodiment of the present invention; Figure 3 for Figure 2 Middle AA section view; Figure 4 A schematic diagram of a multi-operating condition topology optimization model in an embodiment of the present invention; Figure 5 It is an iterative curve of multi-condition topology optimization results in an embodiment of the present invention. DETAILED DESCRIPTION

[0017] The following is a further detailed description of the specific implementation of the present invention in conjunction with the accompanying drawings and examples. The optimization method involved in the embodiment of the present invention includes: Step 1: Obtain the dimensions of multiple existing wheel spoke back cavity weight reduction recesses to obtain the ratio interval between the actual spoke thickness and the spoke thickness before the spoke back cavity weight reduction recesses are dug out.

[0018] Step 2: Obtain the wheel geometry model to be optimized, delete the original weight-reducing dimple area, fill the plane to form a new closed space, and form a new solid geometry model.

[0019] Step 3: According to the proportion interval determined in step 1, take the middle value and segment the design area of ​​the wheel spoke back cavity weight reduction cavity, and divide the grids for the wheel and the weight reduction cavity respectively to obtain the lightweight finite element model of the wheel.

[0020] Step 4: Through the wheel lightweight finite element model, establish the wheel 13° impact condition static model and bending fatigue condition static model respectively, and perform finite element analysis respectively to obtain their respective strain energy results.

[0021] Step 5: Through the wheel lightweight finite element model, the wheel 13° impact condition topology optimization model and the bending fatigue condition topology optimization model are established respectively, and their respective iterative stiffness curves are obtained.

[0022] Step 6: Based on the strain energy results in step 4 and the iterative stiffness curve in step 5, a compromise programming method is used to obtain a comprehensive evaluation function of multiple working conditions of the spoke weight reduction nest, where the multiple working conditions are 13° impact conditions and bending fatigue conditions.

[0023] Step 7: Through the multi-working condition comprehensive evaluation function of the spoke weight reduction pocket, a multi-working condition topology optimization model of the wheel is established, and the multi-working condition topology optimization results are obtained through software analysis.

[0024] Step 8: Perform geometric reconstruction on the topology optimization results and establish a new wheel model.

[0025] Step nine: Perform static finite element analysis of the 13° impact condition and static finite element analysis of bending fatigue on the new wheel model respectively to verify the performance of the new wheel under the 13° impact condition and bending fatigue condition. If the stress results meet the criteria of the wheel manufacturer under the above two conditions, the final spoke back cavity weight reduction dimple structure design is obtained; otherwise, modify the topology optimization parameters and return to step five for re-optimization.

[0026] More specifically, refer to Figure 1 The optimization method involved in the example of the present invention includes the following steps.

[0027] Step 1: According to the design data model of the wheel manufacturer, the software is imported to measure the dimensions of the spoke back cavity weight reduction pockets of multiple existing wheels; combined with the actual casting process design experience of the factory, the actual spoke thickness and the spoke thickness ratio before the spoke back cavity weight reduction pockets are obtained, so as to determine the spoke thickness interval at the spoke back cavity weight reduction pockets and obtain the spoke back cavity weight reduction pocket range; According to statistics, the actual spoke thickness (referring to the spoke thickness after digging the weight-reducing grooves) accounts for 45% to 67% of the spoke thickness before digging the weight-reducing grooves. Based on this range of values, the design interval range of the spoke back cavity weight-reducing grooves can be obtained.

[0028] Step 2: Get a 18×8.5 J wheel geometry model, use Hypermesh software to clean up the model geometry, delete the geometric entities and retain the outer surface, delete the original weight-reducing dimple modeling surface, fill the plane to form a new closed space and generate a new entity.

[0029] Step 3: Measure the thickness of the spoke (before digging the weight-reducing socket) at each position, which is 19.3 mm to 21.7 mm. Take 20 mm. Combined with the value range of 45% to 67% in step 1, take the middle value, i.e. 50%. The draft angle of the weight-reducing socket is 8° to 12°. Take 10°. After calculation, the distance from the bottom of the weight-reducing socket in the back cavity of the spoke to the front face of the spoke (the thickness of the spoke after digging the weight-reducing socket) is 10 mm. Figure 2 As shown, the range of the spoke back cavity weight reduction pockets of the present invention can be obtained, and the wheel spoke back cavity weight reduction pockets can be divided out by cutting the entity; like Figure 2 , 3 As shown, including the weight reduction pocket area 2 and the other wheel area 1, the wheel and the weight reduction pocket parts are meshed separately, and the nodes are overlapped to obtain the lightweight basic model of the wheel.

[0030] Step 4: Establish the static model of the wheel 13° impact condition and the static model of the bending fatigue condition respectively. In the static model of the 13° impact condition, the wheel impact surface is connected to the center point of the surface with a rigid connection RBE2, and the wheel bolt hole is connected to the center point of the wheel flange surface with a rigid connection RBE2 to constrain its six degrees of freedom. In the bending fatigue condition, the rigid connection RBE2 is used to simulate the bolt connection between the loading axis and the wheel mounting surface, constraining all degrees of freedom on the nodes on the inner outer edge of the rim. Static finite element analysis of the wheel 13° impact and bending fatigue is performed respectively, and the strain energy results are obtained respectively. The 13° impact strain energy value is 0.510 MJ, and the bending fatigue strain energy value is 1.389 MJ.

[0031] Step 5: Establish the topology optimization model of the wheel under 13° impact condition and the topology optimization model of the bending fatigue condition respectively, set the weight reduction dimple part as the design area, add the minimum member size constraint of 10 mm, the stress constraint size of the wheel allowable stress of 133.3 MPa, the draft constraint, and the mode group cycle constraint of 5 cycles, take the unit density as the design variable, and the upper limit of the volume fraction response of 50% as the constraint condition. The 13° impact condition takes the minimum flexibility response as the objective function, and the bending fatigue condition takes the minimum weighted flexibility response as the objective function. Perform the topology optimization analysis of the wheel under the single working condition. The specific parameter settings are shown in Table 1 (topology optimization parameter table in the embodiment of the present invention). The topology optimization results and iterative stiffness curves under the two working conditions are obtained respectively, wherein the maximum flexibility of 13° impact is 4220.76 m / N, the minimum flexibility is 3615.27 m / N, the maximum flexibility of bending fatigue is 17075.71 m / N, and the minimum flexibility is 13929.32 m / N.

[0032] Table 1

[0033] Step 6: Extract the strain energy and the maximum and minimum compliance of the two working conditions, and use the compromise planning method to obtain the multi-condition comprehensive evaluation function of the spoke weight reduction cavity, which is calculated as follows;

[0034] In the formula, is the relative density of the material; is the total number of working conditions, take 2; For the The weight coefficient of each working condition is the ratio of the strain energy of the two working conditions; For the loads in different directions under each working condition, take 3; For the Under each working condition The flexibility value in each direction; For the Under each working condition The weight coefficient of each direction; For the The maximum value of the flexibility objective function of each working condition; For the The minimum value of the flexibility objective function for each working condition.

[0035] Step 7: Combine the topology optimization models of the wheel 13° impact and bending fatigue conditions to establish a multi-condition topology optimization model of the wheel, such as Figure 4 As shown, the three arrows at a, b and c are the three load directions of the bending fatigue condition, the line at d is the rigid connection RBE2, e is the wheel, f is the weight reduction groove, the triangle at g is the 13° impact condition constraint, h is the bending fatigue condition constraint, and the arrow at i is the 13° impact condition load direction.

[0036] The weight reduction pocket is set as the design area, and the minimum member size constraint is 10 mm, the stress constraint size is 133.3 MPa, and the draft constraint mode group cycle constraint is 5 cycles. The unit density is used as the design variable, the upper limit of the volume fraction response is 50% as the constraint condition, and the minimum comprehensive evaluation function is used as the objective function. The topology optimization iterative analysis of the wheel multi-condition is carried out to obtain the topology optimization results. The simulation results are viewed using HyperView. When the unit density is 0.3 kg / mm 3 When Figure 5 As shown, A, B, C, D, and E in the figure are all process cloud diagrams of gradual iterative optimization of the weight-reducing nest.

[0037] Step 8: Use OSSmooth to geometrically reconstruct the topology optimization results of multiple working conditions and establish a new wheel model. The mass of the new wheel is 59g less than that of the original wheel.

[0038] Step nine: Perform static finite element analysis of the wheel model under 13° impact conditions and static finite element analysis of bending fatigue to verify the wheel performance. If the stress results meet the criteria, the final spoke back cavity weight reduction structure design is obtained; otherwise, modify the topology optimization parameters and return to step five for re-optimization.

[0039] As described above, the present invention provides a method for designing wheel spoke weight reduction dimples based on multi-working condition topology optimization, which solves the problem of low optimization efficiency of passenger car wheel weight reduction dimples, and proposes a method for structural optimization design of wheel spoke weight reduction dimples that combines the area division of wheel spoke weight reduction dimples with the multi-working condition topology optimization method, providing developers with theoretical and technical guidance for the structural optimization design of wheel spoke weight reduction dimples.

Claims

1. A wheel spoke weight reduction cavity design method based on multi-operating condition topology optimization, characterized in that: The following steps are involved: Step 1: Obtain the dimensions of multiple existing wheel spoke back cavity weight reduction recesses to obtain the ratio of the actual spoke thickness to the spoke thickness before the spoke back cavity weight reduction recesses are dug; Step 2: Obtain the wheel geometry model to be optimized, delete the original weight-reducing dimple area, fill the plane to form a new closed space, and form a new solid geometry model; Step 3: According to the proportion interval determined in step 1, take the middle value, segment the wheel spoke back cavity weight reduction dimple design area, and divide the meshes for the wheel and the weight reduction dimple respectively to obtain the wheel lightweight finite element model; Step 4: Establish a static mechanics model of the wheel 13° impact condition and a static mechanics model of the bending fatigue condition, and perform finite element analysis to obtain strain energy results; Step 5: Establish the topology optimization model of the wheel 13° impact condition and the topology optimization model of the bending fatigue condition respectively, and obtain the iterative stiffness curves respectively; Step 6: Based on the strain energy results in step 4 and the iterative stiffness curve in step 5, a compromise programming method is used to obtain a comprehensive evaluation function of multiple working conditions of the spoke weight reduction pockets; Step 7: Establish a multi-condition topology optimization model for the wheel through the multi-condition comprehensive evaluation function of the spoke weight reduction pocket, and analyze and obtain the multi-condition topology optimization results; Step 8: Perform geometric reconstruction based on the topology optimization results and establish a new wheel model; Step nine: Perform static finite element analysis of the 13° impact condition and static finite element analysis of bending fatigue on the new wheel model respectively to verify the performance of the new wheel under the 13° impact condition and bending fatigue condition. If the stress results meet the criteria of the wheel manufacturer under the above two conditions, the final spoke back cavity weight reduction dimple structure design is obtained; otherwise, modify the topology optimization parameters and return to step five for re-optimization.

2. The method for designing wheel spoke weight reduction pockets based on multi-operating condition topology optimization according to claim 1, characterized in that: Step one includes: according to the wheel manufacturer's design data model, importing the software to measure the dimensions of the spoke back cavity weight reduction dimples of multiple existing wheels; combining the factory's actual casting process design experience to determine the ratio range between the actual spoke thickness and the spoke thickness before the spoke back cavity weight reduction dimples are dug out, and obtaining the spoke back cavity weight reduction dimple design range.

3. The method for designing wheel spoke weight reduction pockets based on multi-operating condition topology optimization according to claim 1, characterized in that: Step 2 includes: obtaining the wheel geometry model, using Hypermesh software to clean up the model geometry, deleting the geometric entities and retaining the outer surface, deleting the original weight-reducing dimple modeling surface, filling the plane to form a new closed space and generating a new entity.

4. The method for designing wheel spoke weight reduction pockets based on multi-operating condition topology optimization according to claim 1, characterized in that: Step 4 includes: establishing a static model of the wheel 13° impact condition and a static model of the bending fatigue condition, respectively, with a grid unit size of 5 mm and a unit type of second-order unit, performing static analysis, and obtaining strain energy results.

5. The method for designing wheel spoke weight reduction pockets based on multi-operating condition topology optimization according to claim 4, characterized in that: In step 4, the static model of the wheel 13° impact condition is to connect the wheel impact surface to the center point of the surface with a rigid connection RBE2, and connect the wheel bolt hole to the center point of the wheel flange surface with a rigid connection RBE2, constraining its six degrees of freedom; the static model of the bending fatigue condition uses a rigid connection RBE2 to simulate the bolt connection between the loading axis and the wheel mounting surface, constraining all degrees of freedom on the inner outer edge nodes of the rim.

6. The method for designing wheel spoke weight reduction pockets based on multi-operating condition topology optimization according to claim 1, characterized in that: The volume fraction response upper limit parameters of the 13° impact condition topology optimization model and the bending fatigue condition topology optimization model in step 5, and the wheel multi-condition topology optimization model in step 7 are all set to 30%~50%.

7. The method for designing wheel spoke weight reduction pockets based on multi-operating condition topology optimization according to claim 6, characterized in that: The loads and boundary conditions of the two single-condition topology optimization models in step five are the same as those of the two single-condition static models in step four. The weight reduction nest is set as the design area, and size constraints, stress constraints, and draft constraints are added. The unit density is used as the design variable, the volume fraction response is used as the constraint condition, and the minimum flexibility response is used as the objective function. OptiStruct is used as the optimization design software.

8. The method for designing wheel spoke weight reduction pockets based on multi-operating condition topology optimization according to claim 1, characterized in that: Step eight includes: using OSSmooth to geometrically reconstruct the topology optimization results of multiple working conditions and establish a new wheel model.

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