A topological optimization method for force transmission path in vehicle offset collision and side collision
By optimizing the topology of the vehicle bias collision and side collision force transmission path of the vehicle body during the conceptual design stage, the problem of difficulty in effectively considering the safety performance of the vehicle body during the conceptual design stage is solved in the existing technology, and the optimization of the collision performance in the early stage of the design is achieved, and the development cycle is shortened.
Patent Information
- Application Number
- CN202210505967.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2022-05-10
- Publication Date
- 2025-03-07
- Estimated Expiration
- 2042-05-10
AI Technical Summary
During the conceptual design stage, it is difficult for the existing technology to effectively consider the collision safety performance of the vehicle body, resulting in limited space for structural changes in the detailed design stage, increasing the difficulty and time cost of collision performance optimization.
The topological optimization method of automobile bias collision and side collision force transmission path is adopted. The body force transmission path under bias collision conditions is obtained through topological optimization during the conceptual design stage, which is used to guide the body design. The method includes establishing a body white model, dynamic nonlinear analysis, applying equivalent static loads and performing static linear optimization, and the optimization target adopts multi-objective optimization.
Optimize collision performance in the early stage of design, guide design, reduce the design and optimization time in the detailed design stage, and shorten the development cycle.
Smart Images
Figure CN115081106B_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of body-in-white optimization design, and specifically discloses a method for topological optimization of force transmission paths for offset collision and side collision of an automobile. Background Art
[0002] The optimization design of the body in white is generally divided into three stages: topological optimization in the early stage of design; optimization of cross-sectional dimensions, joints, etc. in the middle stage of design; and optimization of material thickness and morphology in the late stage of design. The scheme in the early stage of design has not yet been solidified. Topological optimization can achieve lightweighting to the greatest extent and can also bring much greater economic benefits than optimization in the late stage of design.
[0003] At present, when performing multi-condition topology optimization of the vehicle body in the conceptual design stage, usually only the static bending stiffness, torsional stiffness and natural frequency of the vehicle body are considered, and the collision safety performance of the structure is considered in the detailed design stage. In fact, the space for structural changes in the detailed design stage is very limited, which brings great difficulty to the optimization of collision performance and requires more manpower and time. Therefore, it is very necessary to introduce topology optimization of collision safety performance in the conceptual design stage. Summary of the invention
[0004] In view of the technical problems existing in the prior art, the present invention provides a topological optimization method for the force transmission path of an automobile offset collision and a side collision, which is used to obtain the force transmission path of the vehicle body under the offset collision condition through topological optimization in the conceptual design stage, so as to guide the vehicle body design.
[0005] The present invention discloses a method for topological optimization of force transmission paths of offset collision and side collision of automobile, which is used for topological optimization of automobile body in the white body conceptual design stage to obtain force transmission paths based on offset collision and side collision working conditions, and comprises the following steps: S1, establishing a white body model, generating an optimized area of the white body model and meshing the optimized area; S2, performing dynamic nonlinear analysis on the meshed optimized area based on an equivalent static load method to obtain an equivalent static load; S3, applying the equivalent static load to the model, optimizing the static linear model according to set constraints and objective functions, wherein the symmetry constraints and the upper and lower limits of the optimized size are 40 mm-80 mm, the constraints are that the volume fraction of the optimized area is less than 0.2, and the optimization target adopts multi-objective optimization; S4, judging whether the result of the static linear optimization converges, if the result does not converge, updating the design variables according to the optimization result, returning to step S2, if the result converges, ending the step.
[0006] In a preferred embodiment of the present invention, in S1, the grid used to divide the optimization area is a hexahedral grid, and the side length of each hexahedral grid is 20 mm.
[0007] In a preferred embodiment of the present invention, the optimization region of the body-in-white model is determined based on the parameters of the entire vehicle and the positions of the surrounding components.
[0008] In a preferred embodiment of the present invention, a door model and a tire model are added to the body-in-white model.
[0009] In a preferred embodiment of the present invention, in S2,
[0010] S21, based on the equivalent static load method, dynamic nonlinear analysis is performed on the optimized area after meshing to obtain the displacement response;
[0011] S22, calculates the equivalent static load based on the displacement response.
[0012] In a preferred embodiment of the present invention, in S3, the optimization target adopts multi-objective optimization, namely:
[0013]
[0014] a, b, c, d are weight coefficients, and by default a=b=c=d=1, or higher weights may be given to performance of greater concern based on actual conditions;
[0015] D 10 , D 20 , D 30 are the initial values of D1, D2, and D3, i.e., the values before deformation;
[0016] E0 is the strain energy value of the first nonlinear analysis.
[0017] In a preferred embodiment of the present invention, for offset collision, The meaning is as follows:
[0018] F is the objective function, E is the overall strain energy of the optimization area, D1 is the deformation of the firewall, D2 is the deformation of the front cabin, and D3 is the deformation of the front door frame.
[0019] In a preferred embodiment of the present invention, D1: 6 points of X-direction displacement dx1-dx6 are uniformly taken in the left half of the firewall, and two points of X-direction displacement dx7 and dx8 are taken at the roots of the left and right rear longitudinal beams, respectively. The X direction of the vehicle coordinate system is the longitudinal direction of the vehicle, pointing from the front to the rear of the vehicle; the Y direction is the width direction of the vehicle, pointing from the left to the right, and the plane of Y=0 is the left-right symmetric plane of the vehicle;
[0020]
[0021] D2: Take three points in the left half of the front anti-collision beam and evenly take the X-direction displacement dx9-dx 11 ,
[0022]
[0023] D3: Take the X-direction displacement dx of three points on the upper, middle and lower areas of the left outer surface of the A-pillar. 12 -dx 14 , take the X-direction displacement dx of three points on the upper, middle and lower areas of the left outer surface of the B-pillar 15 -dx 17 ,
[0024]
[0025] In a preferred embodiment of the invention, for a side impact, The meaning is as follows:
[0026] F is the objective function, E is the overall strain energy of the optimization area, D1 is the B-pillar intrusion, D2 is the front door intrusion, and D3 is the door sill intrusion.
[0027] In a preferred embodiment of the present invention, D1: Y displacements dy1-dy5 of 5 points are uniformly taken from top to bottom in the left B-pillar, and Y displacements dy6-dy6 of 5 points are uniformly taken from top to bottom in the right B-pillar. 10 , (the X direction of the vehicle coordinate system is the longitudinal direction of the car, pointing from the front to the rear; the Y direction is the width direction of the car, pointing from the left to the right, and the plane where Y=0 is the left-right symmetric plane of the car)
[0028]
[0029] D2: Take the Y displacement dy of 5 points evenly from top to bottom at the inner rear of the left front door (near the B-pillar) 11 -dy 15 , take 5 points evenly from top to bottom at the rear of the right front door (near the B-pillar) and calculate the Y displacement dy 16 -dy 20
[0030]
[0031] D3: Take the Y displacement dy of 5 points from front to back on the left sill (from the rear half of the front floor to the front half of the rear floor). 21 -dy 25 , take the Y displacement dy of 5 points from front to back on the right sill (from the rear half of the front floor to the front half of the rear floor) 26 -dy 30 ,
[0032]
[0033] The beneficial effects of the present invention are as follows: the present invention performs topological optimization on the vehicle body in the conceptual design stage, and obtains a force transmission path based on offset collision and side collision conditions. The present invention, in combination with parametric modeling and optimization technology, can optimize collision performance and guide design in the early design stage, and advance simulation analysis and optimization work, which is conducive to saving design and optimization time in the detailed design stage and reducing the development cycle. BRIEF DESCRIPTION OF THE DRAWINGS
[0034] Figure 1 The present invention is a flow chart of a method for topological optimization of a force transmission path for offset collision and side collision of an automobile. DETAILED DESCRIPTION
[0035] The technical solution of the present invention (including the preferred technical solution) is further described in detail below by means of the accompanying drawings and by listing some optional embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0036] As attached Figure 1 As shown, the present invention discloses a topological optimization method for the force transmission path of an automobile offset collision and a side collision, which is used to perform topological optimization on the body in the white body conceptual design stage to obtain a force transmission path based on the offset collision and the side collision working conditions, and comprises the following steps: S1, establishing a white body model, generating an optimized area of the white body model and meshing the optimized area; S2, performing a dynamic nonlinear analysis on the meshed optimized area based on an equivalent static load method to obtain an equivalent static load; S3, applying the equivalent static load to the model, optimizing the static linear model according to the set constraints and objective function, wherein the symmetry constraints and the upper and lower limits of the optimized size are 40mm-80mm, the constraints are that the volume fraction of the optimized area is <0.2, and the optimization target adopts multi-objective optimization; S4, judging whether the result of the static linear optimization converges, if the result does not converge, updating the design variables according to the optimization result, and returning to step S2, if the result converges, ending the step.
[0037] In a preferred embodiment of the present invention, in S1, the grid used to divide the optimization area is a hexahedral grid, and the side length of each hexahedral grid is 20 mm.
[0038] In a preferred embodiment of the present invention, the optimization region of the body-in-white model is determined based on the parameters of the entire vehicle (such as length, width, height, etc.) and the positions of the surrounding environment parts.
[0039] In a preferred embodiment of the present invention, a door model and a tire model are attached to the body-in-white model (in case of side collision, the door has a greater influence on the collision result, and the door model must be added to the collision model (if there is no detailed door finite element model, a hexahedral mesh is also generated for the door as part of the optimization object). When the vehicle is collided, the tire model must be added to prevent free displacement).
[0040] In a preferred embodiment of the present invention, in S2,
[0041] S21, based on the equivalent static load method, dynamic nonlinear analysis is performed on the optimized area after meshing to obtain the displacement response;
[0042] S22, calculates the equivalent static load based on the displacement response.
[0043] In a preferred embodiment of the present invention, in S3, the optimization target adopts multi-objective optimization, namely:
[0044]
[0045] a, b, c, d are weight coefficients, and by default a=b=c=d=1, or higher weights may be given to performance of greater concern based on actual conditions;
[0046] D 10 , D 20 , D 30 are the initial values of D1, D2, and D3, i.e., the values before deformation;
[0047] E0 is the strain energy value of the first nonlinear analysis.
[0048] In a preferred embodiment of the present invention, for offset collision, The meaning is as follows:
[0049] F is the objective function, E is the overall strain energy of the optimization area, D1 is the deformation of the firewall, D2 is the deformation of the front cabin, and D3 is the deformation of the front door frame.
[0050] In a preferred embodiment of the present invention, D1: 6 points of X-direction displacement dx1-dx6 are uniformly taken in the left half of the firewall, and two points of X-direction displacement dx7 and dx8 are taken at the roots of the left and right rear longitudinal beams, respectively. The X direction of the vehicle coordinate system is the longitudinal direction of the vehicle, pointing from the front to the rear of the vehicle; the Y direction is the width direction of the vehicle, pointing from the left to the right, and the plane of Y=0 is the left-right symmetric plane of the vehicle;
[0051]
[0052] D2: Take three points in the left half of the front anti-collision beam and evenly take the X-direction displacement dx9-dx 11 ,
[0053]
[0054] D3: Take the X-direction displacement dx of three points on the upper, middle and lower areas of the left outer surface of the A-pillar. 12 -dx 14 , take the X-direction displacement dx of three points on the upper, middle and lower areas of the left outer surface of the B-pillar 15 -dx 17 ,
[0055]
[0056] In a preferred embodiment of the invention, for a side impact, The meaning is as follows:
[0057] F is the objective function, E is the overall strain energy of the optimization area, D1 is the B-pillar intrusion, D2 is the front door intrusion, and D3 is the door sill intrusion.
[0058] In a preferred embodiment of the present invention, D1: Y displacements dy1-dy5 of 5 points are uniformly taken from top to bottom in the left B-pillar, and Y displacements dy6-dy6 of 5 points are uniformly taken from top to bottom in the right B-pillar. 10 , (the X direction of the vehicle coordinate system is the longitudinal direction of the car, pointing from the front to the rear; the Y direction is the width direction of the car, pointing from the left to the right, and the plane where Y=0 is the left-right symmetric plane of the car)
[0059]
[0060] D2: Take the Y displacement dy of 5 points evenly from top to bottom at the inner rear of the left front door (near the B-pillar) 11 -dy 15 , take 5 points evenly from top to bottom at the rear of the right front door (near the B-pillar) and calculate the Y displacement dy 16 -dy 20
[0061]
[0062] D3: Take the Y displacement dy of 5 points from front to back on the left sill (from the rear half of the front floor to the front half of the rear floor). 21 -dy 25 , take the Y displacement dy of 5 points from front to back on the right sill (from the rear half of the front floor to the front half of the rear floor) 26 -dy 30 ,
[0063]
[0064] It should be pointed out that the equivalent static load method described in the present invention is a prior art. The idea of the equivalent static load method is to load a series of static loads onto the analysis domain for static analysis so that the displacement generated at any time is the same as the displacement generated by the nonlinear analysis. That is:
[0065] f eq (s) = K L (b)z N (t)(s=s0,s1,…,s n )
[0066] In the formula, f eq (s) is the equivalent load, K L (b) is the model stiffness matrix, z N (t) is the displacement vector. Among them, s and t are one-to-one corresponding, that is, t = t i Equivalent to s=s i This ensures that the displacement of the static linear model is the same as the displacement of the dynamic nonlinear model at any time. There are two analysis models when performing optimization analysis using the equivalent static load method: one is a dynamic nonlinear model for dynamic response analysis; the other is a static linear model for topology optimization.
[0067] It should be further pointed out that the body-in-white modeling, dynamic nonlinear analysis and static linear optimization of the present invention are all based on software directly uniformity familiar to technicians in the relevant technical field. The point of the present invention and the new invention lies in step S3: applying an equivalent static load to the model, and optimizing the static linear model according to the set constraints and objective function. This step is the key step of optimization, and the setting of the optimization parameters has a decisive influence on the results.
[0068] It should be further pointed out that the result convergence in step S4 of the present invention means that there is at least one completed optimized vehicle offset collision and side collision force transmission path in the result. If the path is incomplete or does not exist, there is no convergence.
[0069] Furthermore, when a collision occurs, the car must have good rigidity while ensuring a certain degree of flexibility. Therefore, the use of multi-objective optimization can make the optimization result more in line with actual needs. When a car has a side collision, the protection of the passenger compartment is more of a consideration. The car is required to have good overall rigidity, and the intrusion of the B-pillar, front door, and door sill is as small as possible (to give the occupants enough space). The frontal deformable barrier collision is a head-on collision between the car and the barrier vehicle. Therefore, the overall rigidity, the intrusion of the firewall, the deformation of the front cabin, and the deformation of the front end of the opposite barrier vehicle and the uniformity of the deformation are considered. The present invention is a car colliding with a rigid wall, and the overall rigidity, the intrusion of the firewall, the deformation of the front cabin, and the intrusion of the front door are mainly considered. Different multi-objective optimizations are used for different collision forms to optimize the force transmission path that meets the working conditions.
[0070] It is easy for personnel to understand that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modification, combination, replacement, improvement, etc. made under the spirit and principle of the present invention are included in the protection scope of the present invention.
Claims
1. A method for topological optimization of force transmission paths in vehicle offset collision and side collision, characterized in that: It is used to perform topological optimization of the vehicle body during the conceptual design phase of the vehicle body in white, and obtain the force transmission path based on offset collision and side collision conditions, including the following steps: S1, establishing a body-in-white model, generating an optimized region of the body-in-white model and meshing the optimized region; S2, based on the equivalent static load method, dynamic nonlinear analysis is performed on the optimized area after meshing to obtain the equivalent static load; S3, apply equivalent static load to the model, and optimize the static linear model according to the set constraints and objective function, where the symmetry constraint and the upper and lower limits of the optimization size are 40mm-80mm, the constraint condition is that the volume fraction of the optimization area is less than 0.2, and the optimization target adopts multi-objective optimization; S4, judging whether the result of static linear optimization converges. If the result does not converge, updating the design variables according to the optimization result, and returning to step S2. If the result converges, ending the step; In S3, the optimization objective adopts multi-objective optimization, namely: a, b, c, d are weight coefficients, and by default a=b=c=d=1, or higher weights may be given to performance of greater concern based on actual conditions; D 10 , D 20 , D 30 are the initial values of D1, D2, and D3, i.e., the values before deformation; E0 is the strain energy value of the first nonlinear analysis; For offset collisions, The meaning is as follows: F is the objective function, E is the overall strain energy of the optimization area, D1 is the deformation of the firewall, D2 is the deformation of the front cabin, and D3 is the deformation of the front door frame.
2. The method for topological optimization of force transmission paths for offset collision and side collision of an automobile according to claim 1, characterized in that: In S1, the grid used to divide the optimization area is a hexahedral grid, and the side length of each hexahedral grid is 20 mm.
3. The method for topological optimization of force transmission paths for offset collision and side collision of an automobile according to claim 1, characterized in that: The optimization area of the body-in-white model is determined based on the parameters of the entire vehicle and the location of the surrounding environment parts.
4. The method for topological optimization of force transmission paths for offset collision and side collision of an automobile according to claim 1, characterized in that: The body-in-white model is supplemented with a door model and a tire model.
5. The method for topological optimization of force transmission paths for offset collision and side collision of an automobile according to claim 1, characterized in that: In S2, S21, based on the equivalent static load method, dynamic nonlinear analysis is performed on the optimized area after meshing to obtain the displacement response; S22, calculates the equivalent static load based on the displacement response.
6. The method for topological optimization of force transmission paths in offset collision and side collision of an automobile according to claim 1, characterized in that: D1: Take the X-direction displacement dx1-dx6 of 6 points evenly in the left half of the firewall, and take the X-direction displacement dx7 and dx8 of two points at the root of the left and right rear longitudinal beams respectively. The X-direction of the vehicle coordinate system is the longitudinal direction of the vehicle, pointing from the front to the rear; the Y-direction is the width direction of the vehicle, pointing from the left to the right, and the plane where Y=0 is the left-right symmetric plane of the vehicle; D2: Take three points in the left half of the front anti-collision beam and evenly take the X-direction displacement dx9-dx 11 , D3: Take the X-direction displacement dx of three points on the upper, middle and lower areas of the left outer surface of the A-pillar. 12 -dx 14 , take the X-direction displacement dx of three points on the upper, middle and lower areas of the left outer surface of the B-pillar 15 -dx 17 , 7. The method for topological optimization of force transmission paths in offset collision and side collision of an automobile according to claim 1, characterized in that: For side impacts, The meaning is as follows: F is the objective function, E is the overall strain energy of the optimization area, D1 is the B-pillar intrusion, D2 is the front door intrusion, and D3 is the door sill intrusion.
8. The method for topological optimization of force transmission paths in offset collision and side collision of an automobile according to claim 7, characterized in that: D1: Take 5 points of Y displacement dy1-dy5 evenly from top to bottom on the left B-pillar, and take 5 points of Y displacement dy6-dy evenly from top to bottom on the right B-pillar. 10 , (the X direction of the vehicle coordinate system is the longitudinal direction of the car, pointing from the front to the rear; the Y direction is the width direction of the car, pointing from the left to the right, and the plane where Y=0 is the left-right symmetric plane of the car) D2: Take the Y displacement dy of 5 points evenly from top to bottom at the inner rear of the left front door (near the B-pillar) 11 -dy 15 , take 5 points evenly from top to bottom at the rear of the right front door (near the B-pillar) and calculate the Y displacement dy 16 -dy 20 D3: Take the Y displacement dy of 5 points from front to back on the left sill (from the rear half of the front floor to the front half of the rear floor). 21 -dy 25 , take the Y displacement dy of 5 points from front to back on the right sill (from the rear half of the front floor to the front half of the rear floor) 26 -dy 30 ,