Structure optimization method and device, vehicle body part, vehicle, equipment and medium

Abstract

The invention discloses a structure optimization method and device for a collision working condition, a vehicle body part, a vehicle, equipment and a medium, and the method comprises the steps: determining a continuously changing displacement matrix and stiffness matrix of each finite element on an equivalent model in a collision simulation process, and carrying out the optimization of the collision condition according to the displacement matrix and stiffness matrix of the finite element at a target moment; and updating the load of the target load step applied to the finite element to update the collision simulation on the equivalent model, and based on the equivalent model after collision simulation, carrying out topological optimization on the model structure. According to the method, the stiffness matrix change of the finite element under the action of different load steps is analyzed, different stiffness states under the different load steps are determined, and on the basis of updating of the target load step, each load step can truly show the real-time state of collision, so that the nonlinear process in the collision process is restored with high precision, and the collision accuracy is improved. And the effect and accuracy of structure optimization are enhanced, and lightweight design is achieved while the collision performance of vehicle body parts is guaranteed.

Description

Technical Field

[0001] The present application relates to the field of vehicle technology, and in particular to a structure optimization method, device, vehicle body parts, vehicle, equipment and medium. Background Art

[0002] With the increase in the number of vehicles, domestic and foreign automobile collision safety regulations have upgraded their regulatory requirements in order to restore real traffic accident scenes. At the same time, in order to reduce the cost of using vehicles, lightweighting is another major requirement for car companies. In order to better balance crash resistance and lightweighting, the structural optimization design of each stage of the car becomes crucial.

[0003] Most of the current structural optimization methods are used in the conceptual design stage and cannot provide the most direct design guidance for the detailed design stage of vehicle development. A small number of methods can be applied to the detailed design stage, but the achievable working conditions are greatly restricted. The structural optimization for collision conditions is divorced from engineering reality and the structural optimization effect is poor. Summary of the invention

[0004] Based on this, it is necessary to provide a structural optimization method, device, body parts, vehicle, equipment and medium to address the above-mentioned technical problems, so as to enhance the effect and accuracy of structural optimization and achieve lightweight design while ensuring the crash resistance of body parts.

[0005] A structural optimization method for collision conditions, comprising:

[0006] Determine the displacement matrix and stiffness matrix of the finite element that are constantly changing during the collision simulation, wherein the finite element is a unit area determined after finite element meshing of an equivalent model corresponding to the vehicle body part to be optimized;

[0007] updating the load of the target load step according to the displacement matrix and the stiffness matrix at the target time, so as to update the collision simulation on the equivalent model based on the target load step after the load update, wherein the target time is the action time of the target load step;

[0008] Based on the equivalent model updated by the collision simulation, the model structure is topologically optimized to obtain an optimized target equivalent model, so as to optimize the vehicle body parts to be optimized based on the target equivalent model.

[0009] In the embodiment of the present application, the method of determining the displacement matrix and stiffness matrix of the finite element that are constantly changing during the collision simulation process includes:

[0010] Applying a load on the equivalent model based on a preset load step to perform a collision simulation on the equivalent model;

[0011] During the extraction of the collision simulation process, the displacement matrix of the finite element under different load steps is obtained to determine the continuously changing displacement matrix of the finite element during the collision simulation;

[0012] Based on the displacement matrix of the finite element under different load steps, the displacement difference matrix corresponding to any adjacent load steps is determined;

[0013] For any load step, the target displacement difference matrix caused by the load step is determined from the displacement difference matrix corresponding to the adjacent load steps. According to the target displacement difference matrix and the load corresponding to the load step, the stiffness matrix of the finite element when the load step acts is determined to determine the continuously changing stiffness matrix of the finite element during the collision simulation.

[0014] In the embodiment of the present application, the determining the displacement difference matrix corresponding to any adjacent load steps based on the displacement matrix of the finite element under different load steps includes:

[0015] For any set of adjacent load steps, the displacement matrix at the end of the action of the latter load step in the adjacent load steps is subtracted from the displacement matrix at the end of the action of the former load step in the adjacent load steps to obtain the displacement difference matrix corresponding to the adjacent load steps. The displacement matrix at the end of the action of the load step is the displacement matrix of the finite element carrying the load step under the action of the load step.

[0016] In the embodiment of the present application, the determining the stiffness matrix of the finite element when the load step acts according to the target displacement difference matrix and the load corresponding to the load step includes:

[0017] The load corresponding to the load step is multiplied by the inverse matrix of the target displacement difference matrix to obtain the stiffness matrix of the finite element when the load step acts.

[0018] In the embodiment of the present application, the updating the load of the target load step according to the displacement matrix and the stiffness matrix at the target time includes:

[0019] According to the continuously changing displacement matrix of the finite element during the collision simulation, the velocity matrix and the acceleration matrix of the finite element at the target time are determined;

[0020] According to the displacement matrix, velocity matrix, acceleration matrix and stiffness matrix of the finite element at the target time, the load of the target load step is updated.

[0021] In the embodiment of the present application, the method further includes:

[0022] Combined with the collision conditions, the collision critical area is determined in the vehicle model to determine the equivalent model corresponding to the body parts to be optimized in the collision critical area;

[0023] Modify the equivalent model according to the deviation between the collision variables of the equivalent model and the collision variables of the vehicle model under a collision condition, where the collision variables include the internal energy, velocity, and sectional force of the key components in the vehicle body parts to be optimized under the collision condition.

[0024] A structure optimization device for a collision condition, comprising:

[0025] A determination module, configured to determine the displacement matrix and stiffness matrix that change continuously during a collision simulation of a finite element, where the finite element is a unit area determined after performing finite element mesh division on an equivalent model corresponding to the vehicle body parts to be optimized;

[0026] A load update module, configured to update the load of a target load step according to the displacement matrix and stiffness matrix at a target time, so as to update the collision simulation on the equivalent model based on the target load step after the load is updated, where the target time is the action time of the target load step;

[0027] A topology optimization module, configured to perform topology optimization on the model structure based on the equivalent model after the collision simulation is updated, so as to obtain an optimized target equivalent model, and optimize the vehicle body parts to be optimized based on the target equivalent model.

[0028] In an embodiment of the present application, the determination module is further configured to:

[0029] Apply a load on the equivalent model based on a preset load step to perform a collision simulation on the equivalent model;

[0030] Extract the displacement matrix of the finite element under different load steps during the collision simulation to determine the displacement matrix that changes continuously during the collision simulation of the finite element;

[0031] Determine the displacement difference matrix corresponding to any adjacent load steps based on the displacement matrix of the finite element under different load steps;

[0032] For any load step, determine the target displacement difference matrix caused by the load step from the displacement difference matrix corresponding to the adjacent load steps, and determine the stiffness matrix of the finite element when the load step acts according to the target displacement difference matrix and the load corresponding to the load step, so as to determine the stiffness matrix that changes continuously during the collision simulation of the finite element.

[0033] In an embodiment of the present application, the determination module is further configured to:

[0034] For any set of adjacent load steps, subtract the displacement matrix at the end of the action of the latter load step in the adjacent load steps from the displacement matrix at the end of the action of the former load step in the adjacent load steps to obtain the displacement difference matrix corresponding to the adjacent load steps. The displacement matrix at the end of the action of the load step is the displacement matrix of the finite element carrying the load step under the action of the load step.

[0035] In the embodiment of the present application, the determining module is further configured to:

[0036] Multiply the load corresponding to the load step by the inverse matrix of the target displacement difference matrix to obtain the stiffness matrix of the finite element during the action of the load step.

[0037] In the embodiment of the present application, the load updating module is further configured to:

[0038] Determine the velocity matrix and acceleration matrix of the finite element at the target moment according to the continuously changing displacement matrix of the finite element during the collision simulation process;

[0039] Update the load of the target load step according to the displacement matrix, velocity matrix, acceleration matrix and stiffness matrix of the finite element at the target moment.

[0040] In the embodiment of the present application, the device is further configured to:

[0041] In combination with the collision condition, determine the collision key area in the vehicle model to determine the equivalent model corresponding to the body part to be optimized in the collision key area;

[0042] According to the deviation between the collision variables of the equivalent model and the collision variables of the vehicle model under the collision condition, correct the equivalent model. The collision variables include the internal energy, velocity and sectional force of the key parts in the body part to be optimized under the collision condition.

[0043] A body part is structurally optimized based on the structural optimization method for collision conditions described in the above embodiment.

[0044] A vehicle includes the body part as described in the above embodiment.

[0045] An electronic device includes a memory, a processor, and a computer program stored on the memory and executable on the processor. The electronic device is characterized in that when the processor executes the computer program, the steps of the structural optimization method for collision conditions described in the above embodiment are implemented.

[0046] A computer-readable storage medium stores a computer program. The computer-readable storage medium is characterized in that when the program is executed by a processor, the steps of the structural optimization method for collision conditions described in the above embodiment are implemented.

[0047] In summary, the present application proposes a structural optimization method, device, body part, vehicle, equipment and medium for collision conditions. The method determines the continuously changing displacement matrix and stiffness matrix of each finite element on the equivalent model during the collision simulation. For each finite element, according to the displacement matrix and stiffness matrix of the finite element at the target moment, the load of the target load step applied to the finite element is updated, so as to update the collision simulation on the equivalent model based on the load step after the load update. Based on the equivalent model after the collision simulation, the topology of the model structure is optimized to obtain the optimized target equivalent model, so as to optimize the structure of the vehicle parts to be optimized based on the target equivalent model. The present application analyzes the change of the stiffness matrix of the finite element under different load steps. By updating the target load step, different stiffness matrices are adopted for different load steps, and different stiffness states under different load steps are determined, which greatly reflects the real non-linear load force process of the collision, so that each load step can truly show the real-time state of the collision, rather than the state at the initial moment. In this way, the non-linear process in the collision process is restored with high precision, the effect and accuracy of the structural optimization are enhanced, and the lightweight design is realized while ensuring the collision performance of the body parts. Description of the Drawings

[0048] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments of the present invention. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative work.

[0049] Figure 1 is a flowchart of a structural optimization method for collision conditions shown according to an exemplary embodiment of the present application;

[0050] Figure 2 is a flowchart of a structural optimization method for collision conditions shown according to another exemplary embodiment of the present application;

[0051] Figure 3 is a flowchart of a structural optimization method for collision conditions shown according to still another exemplary embodiment of the present application;

[0052] Figure 4 is a schematic diagram of load update in a structural optimization method for collision conditions shown according to an exemplary embodiment of the present application;

[0053] Figure 5 is a flowchart of a structural optimization method for collision conditions shown according to another exemplary embodiment of the present application;

[0054] Figure 6 is a complete flowchart of a structural optimization method for collision conditions shown in another exemplary embodiment of the present application;

[0055] Figure 7 is a path diagram of topology optimization of an extruded aluminum sill using a structural optimization method for collision conditions shown in another exemplary embodiment of the present application;

[0056] Figure 8 is a structural diagram after optimizing an extruded aluminum sill using a structural optimization method for collision conditions shown in another exemplary embodiment of the present application;

[0057] Figure 9 is a block diagram of a structural optimization device for collision conditions shown in an exemplary embodiment of the present application;

[0058] Figure 10 is a schematic block diagram of a vehicle shown in an exemplary embodiment of the present application;

[0059] Figure 11 is a schematic block diagram of an electronic device shown in an exemplary embodiment of the present application. Detailed implementation manners

[0060] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The embodiments described by referring to the accompanying drawings are exemplary and are intended to explain the present application, and should not be construed as a limitation to the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0061] Figure 1 is a flowchart of a structural optimization method for collision conditions shown in an exemplary embodiment of the present application. As Figure 1 shown, the structural optimization method includes the following steps:

[0062] S101, determining a displacement matrix and a stiffness matrix that continuously change during a collision simulation of a finite element, where the finite element is a unit area determined after performing finite element mesh division on an equivalent model corresponding to a vehicle body part to be optimized.

[0063] The equivalent model can be a simplified model of a vehicle model, and the structure of the vehicle body part to be optimized is included in the equivalent model. In the detailed design stage of vehicle development, it is necessary to optimize the structure of each area of the vehicle body for collision conditions. For example, for collision critical areas such as vehicle body sills, it is first necessary to build a vehicle collision simulation model for this condition according to the requirements of the collision simulation.

[0064] Since a large number of iterative calculations are required for subsequent automated optimization, in order to improve the computational efficiency of the model, the present application simplifies the vehicle model to obtain an equivalent model. The equivalent model is similar to the vehicle model in terms of macroscopic deformation, internal force, etc. The relevant calculations in high-fidelity analysis can be carried out using the equivalent model, which can improve the computational efficiency and save costs.

[0065] Among them, the establishment method and criteria of the equivalent model can be specifically determined according to the purpose of the simulation analysis. If it is required that the equivalent model is close to the overall accuracy of the vehicle model and the stress and deformation conditions of specific feature details in the vehicle model need to be reflected, then the scale of the equivalent model is relatively large. At the same time, the overall and feature deformation, indicators, cross-sectional forces of each transmission path, etc. from a macroscopic perspective should be used as effective criteria. If it is required that the equivalent model is close to the local accuracy of the vehicle model and the simulation purpose is to obtain the optimization trend direction or a local optimization result with high accuracy, then only the overall and feature deformation and other indicators of the local part need to be close. Extracting the equivalent model from the vehicle model needs to meet the requirements of high computational efficiency and the results being consistent with the vehicle results in type or trend to ensure that the subsequent topology optimization design results are more accurate.

[0066] In the embodiment of the present application, for the equivalent model of the vehicle collision simulation condition, compared with the vehicle model, only the components, barriers or equivalent barriers and related connections in the large deformation area can be retained, and the remaining components and related connections can be deleted because they have little impact on this condition. Fix the position of the equivalent model far from the impact point to simulate the constraints of the position with small deformation in the vehicle collision area. The velocity direction and velocity of the barrier in the equivalent model are kept consistent with the vehicle model, and the energy matching between them is ensured through the weight of the barrier, and finally the weight of the barrier is adjusted to a reasonable value. In addition, the node displacements and cross-sectional forces consistent with the vehicle model can be selected as the simulation output items of the equivalent model.

[0067] After determining the equivalent model, using the finite element analysis method, the equivalent model and finite element meshing are carried out, and multiple unit areas are divided on the equivalent model, and each unit area is used as a finite element.

[0068] During the process of carrying out the collision simulation on the equivalent model, the displacement matrix and stiffness matrix that change continuously during the collision of each finite element can be extracted. For example, the displacement matrix of the finite element at the end of each load step is extracted, and the stiffness matrix of the finite element at the start of each load step is extracted, so that the function of the displacement matrix changing with time and the function of the stiffness matrix changing with time can be obtained.

[0069] S102, according to the displacement matrix and stiffness matrix at the target moment, update the load of the target load step, so as to update the collision simulation on the equivalent model based on the target load step after the load is updated, and the target moment is the moment when the target load step acts.

[0070] Loads are applied step by step on each finite element of the equivalent model to perform a collision simulation on the equivalent model. The process of applying loads step by step is to set multiple load steps.

[0071] For each finite element, determine the target time corresponding to the target load step applied to the finite element. This target time is the action time of the target load step, for example, it can be the starting time of the action of the target load step. After determining the displacement matrix and stiffness matrix of the finite element at the target time, update the load of the target load step according to the displacement matrix and the stiffness matrix.

[0072] Among them, the target load step can be selected from the multiple load steps set above, and the target load step that needs to be updated can be determined according to the simulation situation. This application does not make any limitations.

[0073] Apply the updated load of the target load step, that is, the updated load, back to the above-mentioned finite element to update the collision simulation on the equivalent model.

[0074] S103. Based on the equivalent model updated by the collision simulation, perform topology optimization on the model structure to obtain an optimized target equivalent model, so as to optimize the body part to be optimized based on the target equivalent model.

[0075] After updating the loads of one or more target load steps and further updating the collision simulation, based on the equivalent model updated by the collision simulation, perform nonlinear topology optimization on the model structure to obtain an optimized target equivalent model, and optimize the structure of the body part to be optimized based on this target equivalent model.

[0076] In some embodiments, the results of nonlinear topology optimization usually include the mass redistribution rate, element ratio, displacement constraint, and mass ratio diagram. It can be seen from the mass redistribution rate that the model tends to be stable after iteratively calculating a specific number of times. The deletion of elements starts from a specific number of iterations, and the change of mass density runs through each iteration. Since the material mass distribution changes in different iteration steps of topology optimization, and the initial displacement and the constrained displacement value are relatively close, the results of not all iteration steps can meet the initial constraint requirements. Select the iteration result that meets the initial constraint conditions and has a smaller mass as the final optimization result.

[0077] Select the iteration step that meets the requirements as the optimal result, and its result is already in the convergence stage, the displacement meets the constraints, and the mass is the smallest. As the number of iteration steps increases, the elements with small density are gradually deleted.

[0078] In summary, this embodiment proposes a structural optimization method for collision conditions. This method determines the continuously changing displacement matrix and stiffness matrix of each finite element on the equivalent model during the collision simulation. For each finite element, based on the displacement matrix and stiffness matrix of the finite element at the target moment, the load of the target load step applied to the finite element is updated. Based on the load step with updated load, the collision simulation on the equivalent model is updated, and the topology optimization of the model structure is performed to obtain the optimized target equivalent model, so as to optimize the structure of the body part to be optimized based on this target equivalent model. This application analyzes the change of the stiffness matrix of the finite element under different load steps. By updating the target load step, different stiffness matrices are used for different load steps, and different stiffness states under different load steps are determined, which greatly reflects the real non-linear load force process during the collision, enables each load step to truly display the real-time state of the collision instead of the state at the initial moment, thereby restoring the non-linear process during the collision with high precision, enhancing the effect and accuracy of the structural optimization, and realizing lightweight design while ensuring the collision performance of the body parts.

[0079] Based on the above embodiment, as Figure 2 shown, in the above step S101, "determining the continuously changing displacement matrix and stiffness matrix of the finite element during the collision simulation" includes the following steps:

[0080] S201, Based on the preset load steps, apply loads to the equivalent model to perform a collision simulation on the equivalent model.

[0081] Pre-set load steps in the simulation software. Based on these preset load steps, apply loads to the selected finite elements in the equivalent model, so as to perform a collision simulation on the equivalent model.

[0082] S202, Extract the displacement matrix of the finite element under different load steps during the collision simulation.

[0083] Each load step acts on the finite element, causing displacements of each node in the corresponding unit area of the finite element. The displacements of these nodes form the displacement matrix of the finite element. The load steps are applied to the finite element based on time sequence. Therefore, the displacement matrix of the finite element will change with time under the action of different load steps. This application extracts the displacement matrix of the finite element under different load steps during the collision simulation from the simulation software, that is, obtains the continuously changing displacement matrix of the finite element.

[0084] S203, Based on the displacement matrix of the finite element under different load steps, determine the displacement difference matrix corresponding to any adjacent load steps.

[0085] For multiple load steps in time sequence, select any two adjacent load steps, and determine the displacement difference matrix corresponding to these two adjacent load steps according to the displacement matrices of the finite element under the actions of these two load steps respectively.

[0086] S204. For any of the above-mentioned load steps, determine the target displacement difference matrix caused by the load step from the displacement difference matrix corresponding to the adjacent load step, and determine the stiffness matrix of the finite element when the load step acts according to the target displacement difference matrix and the load corresponding to the load step.

[0087] For any load step, determine the two sets of adjacent load steps involved in this load step according to the above steps, and determine the displacement difference matrices of these two sets of adjacent load steps. It is not difficult to understand that the two sets of adjacent load steps involved in this load step are, in chronological order, the adjacent load step composed of this load step and the previous load step of this load step, and the adjacent load step composed of this load step and the next load step of this load step.

[0088] Take the displacement difference matrix corresponding to the adjacent load step composed of this load step and the previous load step of this load step as the target displacement difference matrix caused by this load step.

[0089] According to the target displacement difference matrix caused by this load step and the load corresponding to this load step (i.e., the initial load set at the preset load step), determine the stiffness matrix of the finite element when this load step is applied to the finite element. It can be understood that when this load step acts, it can be the start moment of the action of this load step, or the end moment of the action of the previous load step of this load step.

[0090] In the embodiment of the present application, for any load step, according to the displacement difference matrix caused when this load step acts on the finite element and the load of this load step, determine the stiffness matrix of the finite element at the beginning of the action of this load step (i.e., the start moment of the action of this load step), and configure different stiffness matrices for different load steps accordingly.

[0091] Based on the above embodiment, in the above step S203, "determine the displacement difference matrix corresponding to any adjacent load step based on the displacement matrices of the finite element under different load steps" is realized through the following process:

[0092] For any set of adjacent load steps, subtract the displacement matrix at the end moment of the action of the previous load step in the adjacent load steps from the displacement matrix at the end moment of the action of the latter load step in the adjacent load steps to obtain the displacement difference matrix corresponding to the adjacent load steps. The displacement matrix at the end moment of the action of the load step is the displacement matrix of the finite element bearing the load step under the action of the load step.

[0093] In the embodiments of the present application, for any load step, the displacement matrix of the finite element bearing the load step under the action of the load step is used as the displacement matrix of the finite element at the end moment of the action of the load step.

[0094] For any set of adjacent load steps, subtract the displacement matrix at the end moment of the latter load step in chronological order from the displacement matrix at the end moment of the former load step in the adjacent load steps to obtain the displacement difference matrix corresponding to the adjacent load steps. For example:

[0095] ΔD(t i )=D(t i )-D(t i-1 )

[0096] Where, t i is time, D(t i ) is the displacement matrix at time t i , ΔD(t i ) is the displacement difference matrix within the time of t i and t i-1 , and the moment of t i is the end moment of the i-th load step.

[0097] It is not difficult to understand that the above ΔD(t i ) can be used as the finite element displacement difference matrix caused by the action of the i-th load step.

[0098] Based on the above embodiments, in the above step S204, "determine the stiffness matrix of the finite element when the load step acts according to the target displacement difference matrix and the load corresponding to the load step" is realized through the following process:

[0099] The load corresponding to the load step is the load matrix composed of the loads of each node in the finite element bearing the load step;

[0100] Multiply the load corresponding to the load step (that is, the load matrix composed of the loads of each node in the finite element) by the inverse matrix of the target displacement matrix corresponding to the load step to obtain the stiffness matrix of the finite element when the load step acts. For example:

[0101] F(t i )=K(t i-1 )ΔD(t i )

[0102] Where, F(t i ) is the load at time t i , that is, the load corresponding to the i-th load step from the start moment to the end moment of the action, and K(t i-1 ) is at time t i-1The stiffness matrix at a moment, that is, the stiffness matrix at the end of the action of the (i - 1)-th load step, or the stiffness matrix at the start of the action of the i-th load step, or the stiffness matrix during the action of the i-th load.

[0103] In the embodiment of the present application, for any load step, the stiffness matrix of the finite element at the beginning of the action of the load step can be determined according to the displacement difference matrix caused by a load step acting on the finite element and the load acting on the finite element during the initial collision simulation, so as to determine different stiffness matrices corresponding to different load steps at the beginning of their actions. The present application uses different stiffness matrices for different load steps to determine the load, so as to accurately restore the non-linear process during the collision process.

[0104] On the basis of the above embodiment, as Figure 3 shown, "updating the load of the target load step according to the displacement matrix and stiffness matrix at the target moment" in the above step S102 includes the following steps:

[0105] S301, determining the velocity matrix and acceleration matrix of the finite element at the target moment according to the displacement matrix that continuously changes during the collision simulation of the finite element.

[0106] According to the displacement matrix of the finite element under the action of different load steps determined by the above steps, that is, the displacement matrix of the finite element at the end of the action of different load steps, determine the displacement function D(t) corresponding to the displacement matrix of the finite element; determine the velocity function based on the displacement function and the acceleration function

[0107] Substitute the target action moment corresponding to the target load step that needs to update the load, such as the start moment of the action of the target load step, into the above functions to determine the displacement matrix, velocity matrix and acceleration matrix of the finite element at this time.

[0108] S302, updating the load of the target load step according to the displacement matrix, velocity matrix, acceleration matrix and stiffness matrix of the finite element at the target moment.

[0109] The function K(t) corresponding to the stiffness matrix can be determined according to the stiffness matrix that continuously changes during the collision simulation of the finite element.

[0110] Substitute the target action moment corresponding to the target load step that needs to update the load, such as the start moment of the action of the target load step, into the above function to determine the stiffness matrix of the finite element at this moment.

[0111] In the embodiment of the present application, based on the following formula, update the load F(t) of the target load step according to the displacement matrix, velocity matrix, acceleration matrix and stiffness matrix of the finite element.

[0112]

[0113] Among them, A is the mass matrix and B is the damping matrix.

[0114] Thus, as Figure 4 shown, through the embodiments of the present application, the corresponding stiffness matrix can be determined for different load steps, so as to adaptively adjust the load of the load step. The present application adopts different stiffness matrices for different load steps, realizing different stiffness states of different load steps, greatly reflecting the process of the true non-linear load force in the collision, enhancing the accuracy of the collision simulation, and enhancing the effect of structural optimization.

[0115] Based on the above embodiments, as Figure 5 shown, the embodiments of the present application may further include a correction process for the equivalent model during the construction of the equivalent model, specifically including the following steps:

[0116] S501, in combination with the collision condition, determine the collision critical area in the vehicle model to determine the equivalent model corresponding to the vehicle body parts to be optimized in the collision critical area.

[0117] After constructing the vehicle model, determine the collision critical area on the vehicle body in combination with the collision condition, and simplify the model based on the vehicle body parts to be optimized in the collision critical area to obtain the equivalent model corresponding to the vehicle body parts to be optimized.

[0118] S502, according to the deviation between the collision variables of the equivalent model and the collision variables of the vehicle model under the collision condition, correct the equivalent model, where the collision variables include the internal energy, velocity, and cross-sectional force of the key parts in the vehicle body parts to be optimized under the collision condition.

[0119] In the embodiments of the present application, a deviation threshold corresponding to each collision variable is preset, and based on the deviation threshold, it is determined whether the deviation between the value of the collision variable in the equivalent model and the value of the collision variable in the vehicle model is within the preset deviation range. The collision variables include, but are not limited to, the internal energy, velocity, and cross-sectional force of the key parts in the vehicle body parts to be optimized under the collision condition, etc.

[0120] When the deviation corresponding to the collision variable exceeds the deviation threshold, the equivalent model is corrected again until a qualified equivalent model is obtained.

[0121] For example, calculate the whole vehicle model and the equivalent model respectively. First, compare the macroscopic deformation modes of the key areas to see if the equivalent model is consistent with the whole vehicle model. If not, it is considered that the difference is large and the equivalent model construction steps need to be returned to correct the equivalent model. If they are consistent, then compare whether the internal energy and velocity of the key components of the model differ by less than 5%. If it is greater than 5%, the equivalent model construction steps need to be returned to correct the equivalent model. If they are consistent, then compare whether the deviation of the six sectional forces on the model transmission path is less than 20%. If it is greater than 20%, the equivalent model construction steps need to be returned to correct the equivalent model. Otherwise, proceed to the next step.

[0122] Based on the above embodiments, for the structure optimization method of the present application, after obtaining the target equivalent model by performing topology optimization on the equivalent model, the target equivalent model can also be corrected based on process constraint parameters and other relevant engineering experiences.

[0123] For example, if the design domain is extruded aluminum, then consider the process constraint that the thickness difference between different cavity surfaces should be less than 1.5. The thickness of the design domain needs to meet the process requirements, usually taking one decimal place after the millimeter. If the result shows a thickness less than 0.5 mm, then consider deleting this part. After optimization, relevant holes need to be re-added, and other constraint requirements need to be met to correct the optimized design domain.

[0124] After correction, the target equivalent model can also be substituted into the whole vehicle model for calculation, and the results of the target equivalent model are compared with the results of the whole vehicle model to verify the accuracy of the target equivalent model again. If necessary, the target equivalent model is corrected again to obtain a target equivalent model that meets the lightweight requirements and collision performance requirements, enhancing the effect of structure optimization.

[0125] To clearly and completely describe the structure optimization method for collision conditions proposed in the present application, now in combination with Figure 6 an exemplary description is given: such as Figure 6As shown in the figure, first, a vehicle collision simulation model, i.e., a vehicle model, is constructed. The vehicle model is simplified to extract an equivalent model. The collision simulation results on the equivalent model are compared with those on the vehicle model. The equivalent model is corrected according to the constraints of the result differences. When the result differences are small, the final equivalent model is determined. Nonlinear topology optimization is performed on this equivalent model: that is, the displacement differences corresponding to different load steps during the collision simulation are extracted, and the stiffness matrices corresponding to different load steps are further extracted. The loads at specific load steps are calculated by combining the displacement differences and the stiffness matrices, and these loads are reapplied to the equivalent model to update the collision simulation results on the equivalent model. After the new loads are applied to the equivalent model, the equivalent model is optimized under the action of these improved loads. Then, the topology optimization results of the equivalent model are extracted, and a target equivalent model is generated in combination with the optimization results. Thereafter, the target equivalent model is corrected by combining process and other constraint parameters. The corrected target equivalent model (i.e., the optimized model) is substituted into the vehicle model for verification, and the target equivalent model is further corrected according to the verification results. After meeting the requirements, a lightweight target equivalent model is obtained.

[0126] Next, the optimization process of side pole collision of a certain vehicle model is used for illustration:

[0127] For the equivalent simplified model of side pole collision, compared with the vehicle model, only the seat crossbeam, sill beam, side wall of the battery pack, barrier and related connections are retained, and all other components and related connections are deleted. One side of the seat crossbeam, both ends of the sill beam, and both ends of the side wall of the battery pack are fixed to simulate the constraints of the positions with small deformation in the vehicle away from the collision area. The weights of the barrier, seat crossbeam, and sill beam are used to ensure the energy matching between them.

[0128] The vehicle model and the equivalent model are calculated respectively, and the sum of the internal energies of each cross-section of the sill is extracted. It is found that the internal energies of both models start to rise from 0 and tend to be stable until about 30 ms, and the energy difference between the two is within 5%. The speed curves of both models decrease from the legally specified 8.89 m / s to about -1.6 m / s in the rebound stage. The deformations of the two models are similar, and it can be considered that the equivalent model can basically be equivalent to the trend direction of the topology optimization of the detailed vehicle model. After adopting the equivalent model, the calculation time is reduced from 8 hours of the vehicle model to 17 minutes of the equivalent model, and the efficiency is greatly improved.

[0129] The extruded aluminum sill is used as the design domain and filled with hexahedral elements. Since it has the characteristic of a consistent cross-section along the extrusion direction, the mesh needs to be regularized during filling. The mesh size is 3 mm, the initial mass fraction is 0.4, the minimum strain energy of different load steps is selected as the target, and the difference between different load steps is 3 ms. The mass fraction of 0.4 is selected as the constraint.

[0130] Select the last iteration step as the optimal iteration result, whose result is already in the convergence stage, the mass fraction meets the constraints, and the strain energy is the smallest. As the iteration step increases, the elements with a small threshold density are gradually deleted. The final non-linear topology optimization result is as shown in Figure 7 shown, with two main beam bars and corresponding auxiliary bars appearing. According to engineering experience, it is simplified to the result as shown in Figure 8 . When it is put into the vehicle calculation, it is found that the side column collision performance is basically the same, while the weight can be reduced by 12%.

[0131] Therefore, the structure optimization method proposed in this application introduces intelligent non-linear topology technology into the collision simulation analysis, which can effectively solve the situation of completely relying on manual work for structure optimization. The equivalent model is efficient and has high accuracy. There are engineering practical application cases, which have high guiding significance for the collision simulation analysis. In addition, for the multi-cavity structure of the extruded aluminum sill, the design method of removing the vertical ribs on the upper side in the direction close to the vehicle interior can reduce the weight by more than 12%. This design scheme has a certain generality and can be extended to other vehicle models. At the same time, when ensuring similar performance, the weight is optimized.

[0132] It should be understood that the magnitudes of the sequence numbers of the steps in the above embodiments do not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments of the present application.

[0133] Figure 9 is a block diagram of a structure optimization device for a collision condition according to an exemplary embodiment of the present application, as shown in Figure 9 shown. The device 900 includes: a determination module 901, a load update module 902, and a topology optimization module 902.

[0134] The determination module 901 is used to determine the displacement matrix and stiffness matrix that change continuously during the collision simulation of the finite element, where the finite element is the unit area determined after performing finite element mesh division on the equivalent model corresponding to the vehicle body part to be optimized;

[0135] The load update module 902 is used to update the load of the target load step according to the displacement matrix and stiffness matrix at the target moment, so as to update the collision simulation on the equivalent model based on the target load step after the load is updated, where the target moment is the action moment of the target load step;

[0136] The topology optimization module 903 is used to perform topology optimization on the model structure based on the equivalent model updated by the collision simulation to obtain an optimized target equivalent model, so as to optimize the vehicle body part to be optimized based on the target equivalent model.

[0137] In the embodiments of the present application, the determination module is further used for:

[0138] Apply a load to the equivalent model based on a preset load step to perform a collision simulation on the equivalent model;

[0139] Extract the displacement matrix of the finite element under different load steps during the collision simulation to determine the continuously changing displacement matrix of the finite element during the collision simulation;

[0140] Based on the displacement matrix of the finite element under different load steps, determine the displacement difference matrix corresponding to any adjacent load steps;

[0141] For any load step, determine the target displacement difference matrix caused by the load step from the displacement difference matrix corresponding to the adjacent load steps, and determine the stiffness matrix of the finite element when the load step acts according to the target displacement difference matrix and the load corresponding to the load step, so as to determine the continuously changing stiffness matrix of the finite element during the collision simulation.

[0142] In the embodiment of the present application, the determining module is further configured to:

[0143] For any adjacent load steps, subtract the displacement matrix at the end of the action of the previous load step in the adjacent load steps from the displacement matrix at the end of the action of the latter load step in the adjacent load steps to obtain the displacement difference matrix corresponding to the adjacent load steps. The displacement matrix at the end of the action of the load step is the displacement matrix of the finite element carrying the load step under the action of the load step.

[0144] In the embodiment of the present application, the determining module is further configured to:

[0145] Multiply the load corresponding to the load step by the inverse matrix of the target displacement difference matrix to obtain the stiffness matrix of the finite element when the load step acts.

[0146] In the embodiment of the present application, the load updating module is further configured to:

[0147] Determine the velocity matrix and acceleration matrix of the finite element at the target moment according to the continuously changing displacement matrix of the finite element during the collision simulation;

[0148] Update the load of the target load step according to the displacement matrix, velocity matrix, acceleration matrix and stiffness matrix of the finite element at the target moment.

[0149] In the embodiment of the present application, the device is further configured to:

[0150] Combined with the collision condition, determine the collision key area in the vehicle model to determine the equivalent model corresponding to the vehicle body parts to be optimized in the collision key area;

[0151] According to the deviation between the collision variables of the equivalent model and the collision variables of the vehicle model under a collision condition, the equivalent model is corrected, where the collision variables include the internal energy, velocity, and sectional force of the key parts in the vehicle body parts to be optimized under the collision condition.

[0152] In summary, the structure optimization device for a collision condition proposed in this application determines the continuously changing displacement matrix and stiffness matrix of each finite element on the equivalent model during the collision simulation. For each finite element, according to the displacement matrix and stiffness matrix of this finite element at the target moment, the load of the target load step applied to this finite element is updated. Based on the load step after the load update, the collision simulation on the equivalent model is updated. Based on the equivalent model after the collision simulation, topology optimization is performed on the model structure to obtain the optimized target equivalent model, so as to optimize the structure of the vehicle body parts to be optimized based on this target equivalent model. This application analyzes the change of the stiffness matrix of the finite element under different load steps. By updating the target load step, different stiffness matrices are used for different load steps, and different stiffness states under different load steps are determined, which greatly reflects the real non-linear load stress process of the collision, so that each load step can truly display the real-time state of the collision, rather than the state at the initial moment. In this way, the non-linear process during the collision is restored with high precision, enhancing the effect and accuracy of the structure optimization, and realizing lightweight design while ensuring the collision performance of the vehicle body parts.

[0153] This application also proposes a vehicle body part, and its structure is optimized based on the structure optimization method for a collision condition described in the above embodiment.

[0154] In summary, this application determines the continuously changing displacement matrix and stiffness matrix of each finite element on the equivalent model during the collision simulation. For each finite element, according to the displacement matrix and stiffness matrix of this finite element at the target moment, the load of the target load step applied to this finite element is updated. Based on the load step after the load update, the collision simulation on the equivalent model is updated. Based on the equivalent model after the collision simulation, topology optimization is performed on the model structure to obtain the optimized target equivalent model, so as to optimize the structure of the vehicle body parts to be optimized based on this target equivalent model. This application analyzes the change of the stiffness matrix of the finite element under different load steps. By updating the target load step, different stiffness matrices are used for different load steps, and different stiffness states under different load steps are determined, which greatly reflects the real non-linear load stress process of the collision, so that each load step can truly display the real-time state of the collision, rather than the state at the initial moment. In this way, the non-linear process during the collision is restored with high precision, enhancing the effect and accuracy of the structure optimization, and realizing lightweight design while ensuring the collision performance of the vehicle body parts.

[0155] To implement the above embodiments, an embodiment of the present application further provides a vehicle 1000, as Figure 10 shown, including the body part 1001 described in the above embodiments.

[0156] In summary, the vehicle proposed in the present application includes a body part optimized through the following process: determining the displacement matrix and stiffness matrix that continuously change during the collision simulation for each finite element on the equivalent model, and for each finite element, updating the load of the target load step applied to the finite element according to the displacement matrix and stiffness matrix of the finite element at the target moment, so as to update the collision simulation on the equivalent model based on the load step with updated load, and performing topology optimization on the model structure based on the equivalent model after the collision simulation to obtain an optimized target equivalent model, and optimizing the structure of the vehicle part to be optimized based on the target equivalent model. The present application analyzes the change of the stiffness matrix of the finite element under different load steps, and by updating the target load step, different stiffness matrices are used for different load steps, determining different stiffness states under different load steps, which greatly reflects the real non-linear load force process during the collision, enabling each load step to truly display the real-time state of the collision rather than the state at the initial moment, thereby restoring the non-linear process during the collision with high precision, enhancing the effect and accuracy of the structure optimization, and realizing lightweight design while ensuring the collision performance of the body part.

[0157] To implement the above embodiments, an embodiment of the present application further provides an electronic device 1100, as Figure 11 shown, the electronic device 1100 may specifically include: a memory 1101, a processor 1102, and a computer program stored on the memory 1101 and executable on the processor 1102. When the processor 1102 executes the program, it implements the steps of the structure optimization method for the collision condition as shown in the above embodiments.

[0158] In summary, for the electronic device proposed in this application, during the collision simulation process, the displacement matrix changes and stiffness matrix changes corresponding to each finite element on the equivalent model are determined. For each finite element, based on the displacement matrix change and stiffness matrix change corresponding to this finite element, the load of the target load step applied to this finite element is updated, so as to update the collision simulation on the equivalent model based on the load step with updated load. Based on the equivalent model after the collision simulation, topology optimization is performed on the model structure to obtain an optimized target equivalent model, so as to optimize the structure of the vehicle parts to be optimized based on this target equivalent model. This application analyzes the changes in the stiffness matrix of finite elements under different load steps. By updating the target load step, different stiffness matrices are used for different load steps, realizing different stiffness states for different load steps, greatly reflecting the real non-linear load force process during the collision, enabling each load step to truly display the real-time state of the collision rather than the state at the initial moment, thereby restoring the non-linear process during the collision with high precision, enhancing the effect and accuracy of structural optimization, and achieving lightweight design while ensuring the collision performance of the body parts.

[0159] Those of ordinary skill in the art can understand that all or part of the processes of implementing the methods in the above embodiments can be completed by instructing relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above methods. Among them, any reference to a memory, storage, database or other medium used in the embodiments provided in this application can include non-volatile and / or volatile memories. Non-volatile memories can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memories can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.

[0160] Those skilled in the art can clearly understand that, for the convenience and brevity of description, only the division of the above functional units and modules is used as an example. In actual applications, the above functions can be allocated to different functional units and modules according to needs, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above.

[0161] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A structural optimization method for collision conditions, characterized in that Including: Determine the displacement matrix and stiffness matrix that are constantly changing during the collision simulation for the finite elements, where the finite elements are the unit areas determined after performing finite element mesh division on the equivalent model corresponding to the vehicle body part to be optimized; According to the displacement matrix and stiffness matrix at the target moment, update the load of the target load step, and based on the target load step with the updated load, update the collision simulation on the equivalent model, where the target moment is the acting moment of the target load step; Based on the equivalent model updated by the collision simulation, perform topology optimization on the model structure to obtain the optimized target equivalent model, so as to optimize the vehicle body part to be optimized based on the target equivalent model.

2. The method according to claim 1, wherein The determination of the displacement matrix and stiffness matrix that are constantly changing for the finite elements during the collision simulation includes: Based on a preset load step, apply a load on the equivalent model to perform a collision simulation on the equivalent model; Extract the displacement matrix of the finite elements under different load steps during the collision simulation to determine the displacement matrix that is constantly changing for the finite elements during the collision simulation; Based on the displacement matrix of the finite elements under different load steps, determine the displacement difference matrix corresponding to any adjacent load steps; For any load step, determine the target displacement difference matrix caused by the load step from the displacement difference matrix corresponding to the adjacent load steps, and according to the target displacement difference matrix and the load corresponding to the load step, determine the stiffness matrix of the finite elements when the load step acts, so as to determine the stiffness matrix that is constantly changing for the finite elements during the collision simulation.

3. The method according to claim 2, wherein The determination of the displacement difference matrix corresponding to any adjacent load steps based on the displacement matrix of the finite elements under different load steps includes: For any set of adjacent load steps, subtract the displacement matrix at the end of the action of the previous load step in the adjacent load steps from the displacement matrix at the end of the action of the latter load step in the adjacent load steps to obtain the displacement difference matrix corresponding to the adjacent load steps; The displacement matrix at the end of the action of the load step is the displacement matrix of the finite elements carrying the load step under the action of the load step.

4. The method according to claim 2, characterized in that, The determination of the stiffness matrix of the finite elements when the load step acts according to the target displacement difference matrix and the load corresponding to the load step includes: Multiply the load corresponding to the load step by the inverse matrix of the target displacement difference matrix to obtain the stiffness matrix of the finite elements when the load step acts.

5. The method according to claim 1, wherein The update of the load of the target load step according to the displacement matrix and stiffness matrix at the target moment includes: According to the displacement matrix that is constantly changing for the finite elements during the collision simulation, determine the velocity matrix and acceleration matrix of the finite elements at the target moment; According to the displacement matrix, velocity matrix, acceleration matrix and stiffness matrix of the finite elements at the target moment, update the load of the target load step.

6. The method according to any one of claims 1-5, characterized in that, The method further includes: Combined with the collision condition, determine the collision critical area in the whole vehicle model to determine the equivalent model corresponding to the vehicle body part to be optimized in the collision critical area. According to the deviation between the collision variables of the equivalent model and the collision variables of the vehicle model under collision conditions, the equivalent model is corrected. The collision variables include the internal energy, velocity, and sectional force of the key components in the body parts to be optimized under collision conditions.

7. A structural optimization device for collision conditions, characterized in that, Comprising: A determination module, configured to determine the displacement matrix and stiffness matrix that change continuously during the collision simulation of the finite element. The finite element is the unit area determined after performing finite element mesh division on the equivalent model corresponding to the body parts to be optimized. A load update module, configured to update the load of the target load step according to the displacement matrix and stiffness matrix at the target moment, so as to update the collision simulation on the equivalent model based on the target load step after the load is updated. The target moment is the action moment of the target load step. A topology optimization module, configured to perform topology optimization on the model structure based on the equivalent model updated by the collision simulation to obtain an optimized target equivalent model, so as to optimize the body parts to be optimized based on the target equivalent model.

8. A vehicle body part, characterized in that, Perform structural optimization according to the structural optimization method for collision conditions described in any one of claims 1-6.

9. A vehicle, characterized in that, Comprising the body parts described in claim 8.

10. An electronic device, comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, When the processor executes the computer program, the steps of the structural optimization method for collision conditions described in any one of claims 1-6 are implemented.

11. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by the processor, the steps of the structural optimization method for collision conditions described in any one of claims 1-6 are implemented.

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