Front auxiliary frame lightweight design method and device and vehicle

Abstract

The invention provides a front auxiliary frame lightweight design method and device and a vehicle, and the method comprises the steps: obtaining a nonlinear finite element model, solving the nonlinear finite element model, obtaining a displacement time function of a front auxiliary frame installation point and an internal energy gradient time function of a filling unit, and obtaining the internal energy gradient time function of the filling unit; screening time points in the displacement time function and time points in the internal energy gradient time function to obtain a target time point, determining a loading point reaction function and a displacement value of a collision equivalent static working condition, and generating a collision linear model based on front subframe data and body-in-white data, constructing a topological function based on the reaction force of all the loading points, all the displacement values and a reaction force function of the loading points, and performing iterative solution on the topological function by taking minimization of the topological function as a target; according to the method, the design period is shortened, the calculation complexity is reduced, the contradiction between the collision energy absorption and the whole vehicle rigidity is effectively solved, and the calculation accuracy of the relative density output value is improved.

Description

Technical Field

[0001] The present application relates to the field of lightweight design technology, and in particular to a method, device and vehicle for lightweight design of a front subframe. Background Art

[0002] Lightweight design is a method of reducing structural weight while meeting performance requirements by optimizing material distribution, structural topology or material selection. It is widely used in aerospace, automotive manufacturing, mechanical engineering and construction.

[0003] In the automotive industry, lightweight design is primarily performed based on statics assumptions for topology optimization (for example, the Solid Isotropic Material with Penalization (SIMP) method). This topology optimization approach has the following drawbacks: it ignores dynamic nonlinear effects under collision conditions (such as material plastic deformation and contact friction), resulting in a mismatch between force transmission paths and actual collision energy absorption requirements. Furthermore, it performs serial optimization on performance factors such as collision safety and bending and torsional stiffness. This serial optimization model struggles to reconcile collision energy absorption (which requires local flexibility) with overall vehicle stiffness (which requires high stiffness). Consequently, the design results require multiple iterative compromises, resulting in long design cycles and difficulty in achieving a global optimal solution. Summary of the Invention

[0004] In view of the above-mentioned shortcomings of the prior art, the present application provides a front subframe lightweight design method, device and vehicle to solve the above-mentioned technical problems.

[0005] According to one aspect of an embodiment of the present application, a method for lightweight design of a front subframe is provided, comprising: obtaining a nonlinear finite element model for collision simulation of a whole vehicle, the nonlinear finite element model comprising front subframe data and body-in-white data; the front subframe data is determined by attribute information of a filling unit; the filling unit is used to fill a spatial area of ​​the front subframe; solving the nonlinear finite element model to obtain a displacement time function of a front subframe mounting point and an internal energy gradient time function of the filling unit; and screening the time points in the displacement time function and the time points in the internal energy gradient time function to obtain a target time point; determining a collision according to the displacement field of the target time point, the unit stiffness matrix of the filling unit, and the relative density variable of the filling unit. A loading point support reaction function of an equivalent static working condition; and according to the target time point and the displacement time function, determining the displacement value of the collision equivalent static working condition; generating a collision linear model based on the front subframe data and the body-in-white data; the collision linear model is used to characterize the loading point support reaction and displacement values ​​generated under the chassis attachment point stiffness working condition, the loading point support reaction and displacement values ​​generated under the bending stiffness working condition, and the loading point support reaction and displacement values ​​generated under the torsional stiffness working condition; based on all loading point support reactions, all displacement values ​​and the loading point support reaction function, constructing a topological function, with the goal of minimizing the topological function, iteratively solving the topological function to obtain a relative density output value, so as to perform a lightweight design on the front subframe through the relative density output value.

[0006] In one embodiment of the present application, the process of screening the time points in the displacement time function and the time points in the internal energy gradient time function to obtain the target time point includes: screening the displacement values ​​in the displacement time function according to the displacement screening condition to obtain the screened displacement value, and using the time point corresponding to the screened displacement value as the first screening time point; the displacement screening condition includes: selecting the displacement value in the displacement time function that is greater than or equal to the preset safety threshold; screening the internal energy gradient value in the internal energy gradient time function according to the internal energy gradient screening condition to obtain the screened internal energy gradient value, and using the time point corresponding to the screened internal energy gradient value as the second screening time point; the internal energy gradient screening condition includes: selecting the internal energy gradient maximum point and the point where the internal energy gradient turns from positive to negative; based on the internal energy gradient time function, calculating the internal energy score at the first screening time point and the second screening time point; based on the internal energy score and the time point spacing, screening the first screening time point and the second screening time point to obtain the target time point.

[0007] In one embodiment of the present application, the calculation formula for the internal energy score includes: ， in, represents the internal energy score, Indicates the i Screening time point, i The screening time point is the first screening time point or the second screening time point, Indicates the first screening time point, represents the weighting factor of the energy absorption rate, represents the weight factor of the accumulated energy, represents the weight factor of the front subframe mounting point displacement penalty term, Represents the attenuation coefficient, which is used to control the attenuation coefficient of the displacement penalty term of the front subframe mounting point. represents the absolute value of the internal energy gradient time function, It represents the internal energy time function obtained by integrating the internal energy gradient time function in the time dimension.

[0008] In one embodiment of the present application, based on the internal energy score and the time point spacing, the first screening time point and the second screening time point are screened to obtain the target time point. The process includes: if the time point spacing is less than or equal to a preset distance threshold, and the difference in the internal energy scores of the two screening time points obtained by calculating the time point spacing is less than or equal to the preset score threshold, then deleting the time point with the smaller internal energy score in the two screening time points obtained by calculating the time point spacing; taking the time point remaining after deleting the first screening time point and the second screening time point as the update time point, or combining the first screening time point and the second screening time point to obtain a first combined time point, and taking the first combined time point as the update time point; integrating the internal energy gradient time function according to the time dimension to obtain the internal energy time function; dividing the internal energy time function into elastic and elastic time functions according to the comparison result of the internal energy gradient standard deviation of each time point and the preset standard deviation threshold. stage, plastic development stage and stable stage; compare the update time point with the time range of the elastic stage to obtain the elastic stage time point; compare the update time point with the time range of the plastic development stage to obtain the plastic development stage time point; compare the update time point with the time range of the stable stage to obtain the stable stage time point; according to the internal energy score of the elastic stage time point, select a first preset number of time points from the elastic stage time point; according to the internal energy score of the plastic development stage time point, select a second preset number of time points from the plastic development stage time point; according to the internal energy score of the stable stage time point, select a third preset number of time points from the stable stage time point; combine the first preset number of time points, the second preset number of time points and the third preset number of time points to obtain a second combination time point, and use the second combination time point as the target time point.

[0009] In one embodiment of the present application, before obtaining a nonlinear finite element model for performing collision simulation on the entire vehicle, the method further includes: obtaining front subframe envelope data; the front subframe envelope data is derived from a front subframe unit in a preset collision finite element model; based on the front subframe envelope data, the front subframe space area is established, and the front subframe space area is filled with the filling unit to obtain a front subframe space area unit; the attribute information of the filling unit is consistent with the attribute information of the front subframe unit; the front subframe unit is replaced by the front subframe space area unit, and the connection relationship and position relationship between the front subframe and preset components are configured to obtain the nonlinear finite element model; the preset components include a body-in-white, a chassis component, and a suspension bracket.

[0010] In one embodiment of the present application, the expression of the loading point support reaction function includes: ,in, represents the loading point support reaction function, Indicates The displacement field at a point in time, Indicates the s target time points, represents the stiffness matrix; the expression of the stiffness matrix includes: ， in, represents the stiffness matrix, Indicates the i The relative density variable of the filling unit, p represents the penalty factor, Indicates the i The element stiffness matrix of the infill element.

[0011] In one embodiment of the present application, the process of iteratively solving the topological function with the goal of minimizing the topological function includes: obtaining the current relative density value of the filling unit; inputting the current relative density value into the topological function to obtain the current weighted flexibility, and counting the number of iterations; using the relative density variable as the design variable, derivatizing the topological function in the design variable dimension to obtain the gradient function of the design variable; inputting the current relative density value into the gradient function to obtain the initial sensitivity of the design variable; and updating the current relative density value based on the initial sensitivity. , obtain an updated relative density value; input the updated relative density value into the topological function to obtain an updated weighted flexibility, and update the number of iterations; calculate the flexibility change between the current weighted flexibility and the updated weighted flexibility, and calculate the density value change between the updated relative density value and the current relative density value; determine the number of iterations of the topological function and the relative density output value based on the comparison result of the flexibility change with the preset flexibility change threshold, the comparison result of the density value change with the preset density value change threshold, and the comparison result of the updated number of iterations with the preset iteration number threshold.

[0012] In one embodiment of the present application, the expression of the topological function includes:

[0013] ,

[0014]

[0015] in, represents the weighted flexibility, For the i The relative density variable of the filling unit, represents the weighting coefficient of the collision equivalent static condition, represents the weighting coefficient of the chassis attachment point stiffness case, represents the weighting coefficient of the bending stiffness case, represents the weighting coefficient of the torsional stiffness case, represents the loading point support reaction function, represents the loading point support reaction for the chassis attachment point stiffness case, represents the loading point support reaction for the bending stiffness case, represents the loading point support reaction for the torsional stiffness condition, Indicates the s The displacement value of the target time point, represents the displacement value of the chassis attachment point stiffness case, represents the displacement value of the bending stiffness case, represents the displacement value of the torsional stiffness condition, Indicates The displacement field at a point in time, Indicates the s target time points, represents the stiffness matrix, represents the quality fraction of the design domain, Indicates the number of chassis attachment points.

[0016] According to one aspect of an embodiment of the present application, a front subframe lightweight design device is provided, comprising: a data acquisition module for acquiring a nonlinear finite element model for performing collision simulation on a whole vehicle, wherein the nonlinear finite element model comprises front subframe data and body-in-white data; the front subframe data is determined by attribute information of a filling unit; the filling unit is used to fill the front subframe space area; a time point screening module for solving the nonlinear finite element model to obtain a displacement time function of a front subframe mounting point and an internal energy gradient time function of the filling unit; and screening the time points in the displacement time function and the time points in the internal energy gradient time function to obtain a target time point; a static working condition calculation module for calculating the target time point based on the displacement field of the target time point, the unit stiffness matrix of the filling unit, and the relative density variable of the filling unit. , determine the loading point support reaction function of the collision equivalent static working condition; and determine the displacement value of the collision equivalent static working condition according to the target time point and the displacement time function; a model conversion module, used to generate a collision linear model based on the front subframe data and the white body data; the collision linear model is used to characterize the loading point support reaction and displacement values ​​generated under the chassis attachment point stiffness working condition, the loading point support reaction and displacement values ​​generated under the bending stiffness working condition, and the loading point support reaction and displacement values ​​generated under the torsional stiffness working condition; a function solving module, used to construct a topological function based on all loading point support reactions, all displacement values ​​and the loading point support reaction function, with the goal of minimizing the topological function, iteratively solve the topological function to obtain a relative density output value, so as to perform lightweight design on the front subframe through the relative density output value.

[0017] According to one aspect of an embodiment of the present application, a vehicle is provided, comprising the front subframe lightweight design method as described above.

[0018] Beneficial effects of the present application: The present application obtains a nonlinear finite element model for collision simulation of the entire vehicle, solves the nonlinear finite element model, obtains the displacement time function of the front subframe mounting point and the internal energy gradient time function of the filling unit, and screens the time points in the displacement time function and the time points in the internal energy gradient time function to obtain the target time point, determines the loading point support reaction function of the collision equivalent static working condition according to the displacement field of the target time point, the unit stiffness matrix of the filling unit, and the relative density variable of the filling unit, and determines the displacement value of the collision equivalent static working condition according to the target time point and the displacement time function, generates a collision linear model based on the front subframe data and the body-in-white data, and constructs a topological function based on all loading point support reactions, all displacement values ​​and the loading point support reaction function to minimize the topological function With the goal of achieving the desired effect, the topological function is iteratively solved to obtain the relative density output value, so as to perform lightweight design on the front subframe through the relative density output value. The above process fully considers the dynamic nonlinear effect under the collision condition, and establishes a topological function based on the collision equivalent static condition, the chassis attachment point stiffness condition, the bending stiffness condition and the torsional stiffness condition. The topological function is iteratively solved to obtain the relative density output value, avoiding iterative solution through the serial optimization model in multiple working conditions, greatly shortening the design cycle, and effectively solving the contradiction between collision energy absorption and vehicle stiffness, thereby improving the accuracy of the relative density output value calculation. At the same time, by converting the nonlinear finite element model into a linear model, the computational complexity of iterative solution of the topological function is greatly reduced, which helps to improve the calculation rate of the relative density output value.

[0019] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings are incorporated into and constitute a part of the specification, illustrating embodiments consistent with the present application and, together with the specification, serving to explain the principles of the present application. It is obvious that the drawings described below are merely some embodiments of the present application, and a person of ordinary skill in the art can derive other drawings based on these drawings without inventive effort. In the drawings: Figure 1 is a schematic diagram of an exemplary system architecture shown in an exemplary embodiment of the present application; Figure 2 is a flow chart of a front subframe lightweight design method shown in an exemplary embodiment of the present application; Figure 3 is a flow chart of a front subframe lightweight design method shown in another exemplary embodiment of the present application; Figure 4is a schematic diagram of a front subframe space area shown in an exemplary embodiment of the present application; Figure 5 is a schematic diagram of an internal energy time function shown in an exemplary embodiment of the present application; Figure 6 is a schematic diagram of an internal energy gradient time function shown in an exemplary embodiment of the present application; Figure 7 is a relative density contour cloud diagram of the front subframe space area shown in an exemplary embodiment of the present application; Figure 8 is a block diagram of a front subframe lightweight design device shown in an exemplary embodiment of the present application; Figure 9 A schematic diagram of the structure of a computer system suitable for implementing an electronic device according to an embodiment of the present application is shown. DETAILED DESCRIPTION

[0021] Exemplary embodiments will be described in detail herein, with examples illustrated in the accompanying drawings. When the following description refers to the drawings, identical numerals in different figures represent identical or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all embodiments consistent with the present application. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present application, as detailed in the appended claims.

[0022] The block diagrams shown in the accompanying drawings are merely functional entities and do not necessarily correspond to physically separate entities. That is, these functional entities may be implemented in software, in one or more hardware modules or integrated circuits, or in different networks and / or processor devices and / or microcontroller devices.

[0023] The flowcharts shown in the accompanying drawings are for illustrative purposes only and do not necessarily include all contents and operations / steps, nor must they be executed in the order described. For example, some operations / steps may be decomposed, while others may be combined or partially combined. Therefore, the actual execution order may vary depending on the actual situation.

[0024] In this application, "plurality" refers to two or more. "And / or" describes the relationship between related objects, indicating that three possible relationships exist. For example, "A and / or B" can mean: A exists alone, A and B exist simultaneously, and B exists alone. The character " / " generally indicates that the related objects are in an "or" relationship.

[0025] The technical solutions of the embodiments of this application involve path planning and other related technologies, which are specifically described through the following embodiments: Figure 1It is a schematic diagram of an exemplary system architecture shown in an exemplary embodiment of the present application.

[0026] Reference Figure 1 As shown, the system architecture may include a storage device 101 and an electronic device 102. The electronic device 102 may be at least one of a desktop graphics processing unit (GPU) computer, a GPU computing cluster, a neural network computer, and the like. Relevant technical personnel can use the electronic device 102 to obtain a nonlinear finite element model for collision simulation of the entire vehicle, solve the nonlinear finite element model, obtain the displacement time function of the front subframe mounting point and the internal energy gradient time function of the filling unit, and screen the time points in the displacement time function and the time points in the internal energy gradient time function to obtain the target time point. According to the displacement field of the target time point, the unit stiffness matrix of the filling unit, and the relative density variable of the filling unit, the loading point support reaction function of the collision equivalent static working condition is determined, and the displacement value of the collision equivalent static working condition is determined according to the target time point and the displacement time function. Based on the front subframe data and the white body data, a collision linear model is generated, and based on all loading point support reactions, all displacement values ​​and loading point support reaction functions, a topology function is constructed. With the goal of minimizing the topology function, the topology function is iteratively solved to obtain a relative density output value, so as to perform lightweight design on the front subframe through the relative density output value. The storage device 101 is used to store the nonlinear finite element model, and the front subframe data and body-in-white data in the nonlinear finite element model, and provide the data to the electronic device 102 for processing.

[0027] Schematically, after acquiring the nonlinear finite element model, front subframe data and body-in-white data of the storage device 101, the electronic device 102 solves the nonlinear finite element model to obtain the displacement time function of the front subframe mounting point and the internal energy gradient time function of the filling unit, and filters the time points in the displacement time function and the time points in the internal energy gradient time function to obtain the target time point, and determines the loading point support reaction function of the collision equivalent static working condition according to the displacement field of the target time point, the unit stiffness matrix of the filling unit, and the relative density variable of the filling unit, and determines the displacement value of the collision equivalent static working condition according to the target time point and the displacement time function, generates a collision linear model based on the front subframe data and the body-in-white data, and constructs a topological function based on all loading point support reactions, all displacement values ​​and loading point support reaction functions. With the goal of minimizing the topological function, the topological function is iteratively solved to obtain the relative density output value, so as to perform lightweight design on the front subframe through the relative density output value. The above process fully takes into account the dynamic nonlinear effects under the collision condition, and establishes the topological function based on the collision equivalent static condition, the chassis attachment point stiffness condition, the bending stiffness condition and the torsional stiffness condition. The topological function is iteratively solved to obtain the relative density output value, avoiding the iterative solution through the serial optimization model in multiple working conditions, greatly shortening the design cycle, improving the accuracy of the relative density output value calculation, and effectively solving the contradiction between collision energy absorption and vehicle stiffness. At the same time, by converting the nonlinear finite element model into a linear model, the computational complexity of the iterative solution of the topological function is greatly reduced, which helps to improve the calculation rate of the relative density output value.

[0028] It should be noted that the front subframe lightweight design method provided in the embodiment of the present application is generally executed by the electronic device 102 , and accordingly, the front subframe lightweight design device is generally provided in the electronic device 102 .

[0029] The following is a detailed description of the implementation details of the technical solution of the embodiment of the present application: Figure 2 is a flowchart of a front subframe lightweight design method shown in an exemplary embodiment of the present application. The front subframe lightweight design method can be executed by a computing and processing device. The computing and processing device can be Figure 1 The electronic device 102 shown in FIG. Figure 2 As shown, the front subframe lightweight design method includes at least steps S210 to S250, which are described in detail as follows: In step S210, a nonlinear finite element model for performing crash simulation on the entire vehicle is obtained. In one embodiment of the present application, the nonlinear finite element model includes front subframe data and body-in-white data. The front subframe data is determined by the attribute information of filler cells. The filler cells are used to fill the space area of ​​the front subframe. The attribute information of the filler cells includes the filler cell's material type, relative density, elastic modulus, stress, thermal conductivity, etc. The filler cells can be first-order hexahedron cells, tetrahedron cells, quadrangular prisms, pentahedrons, etc.

[0030] In step S220, the nonlinear finite element model is solved to obtain the displacement-time function of the front subframe mounting point and the internal energy gradient-time function of the filling element. The time points in the displacement-time function and the internal energy gradient-time function are then filtered to obtain the target time point. In one embodiment of the present application, the nonlinear finite element model is solved using nonlinear finite element analysis software, LS-DYNA (Livermore Software Technology Corporation - DYNA). The process of screening the time points in the displacement time function and the time points in the internal energy gradient time function to obtain the target time point includes: screening the displacement value in the displacement time function according to the displacement screening condition to obtain the screened displacement value, and taking the time point corresponding to the screened displacement value as the first screening time point; screening the internal energy gradient value in the internal energy gradient time function according to the internal energy gradient screening condition to obtain the screened internal energy gradient value, and taking the time point corresponding to the screened internal energy gradient value as the second screening time point; calculating the internal energy score at the first screening time point and the second screening time point based on the internal energy gradient time function; screening the first screening time point and the second screening time point based on the internal energy score and the time point interval to obtain the target time point.

[0031] In step S230, the load-point support reaction function for the collision-equivalent static condition is determined based on the displacement field at the target time point, the element stiffness matrix of the infill element, and the relative density variable of the infill element. Furthermore, the displacement value for the collision-equivalent static condition is determined based on the target time point and the displacement-time function. In one embodiment of the present application, once the displacement-time function is obtained, the target time point is input into the displacement-time function to obtain the displacement value for the collision-equivalent static condition.

[0032] The expression of the loading point support reaction function is as follows: Formula (1) in, represents the loading point support reaction function, Indicates The displacement field at a point in time, Indicates the starget time points, represents the stiffness matrix; The expressions for the stiffness matrix include: Formula (2) in, represents the stiffness matrix, represents the relative density variable of the i-th filling unit, p represents the penalty factor, Indicates the i The element stiffness matrix of the infill element.

[0033] In step S240, a linear collision model is generated based on the front subframe data and the body-in-white (BIW) data. In one embodiment of the present application, the linear collision model is used to characterize the load-point support reaction forces and displacement values ​​generated under the chassis attachment point stiffness condition, the load-point support reaction forces and displacement values ​​generated under the bending stiffness condition, and the load-point support reaction forces and displacement values ​​generated under the torsional stiffness condition. The loading method for the bending stiffness condition includes constraining the displacement and rotational degrees of freedom of the front suspension shock absorber mounting points of the BIW, constraining the displacement and rotational degrees of freedom of the rear suspension shock absorber mounting points of the BIW, and applying a predetermined force (e.g., 2000N) vertically downward to the left side of the midpoint of the sill and a predetermined force (e.g., 2000N) vertically downward to the right side of the midpoint of the sill. Under the loading conditions of this bending stiffness condition, the bending stiffness is greater than or equal to the target bending stiffness value. The loading method of the torsional stiffness working condition includes: constraining the displacement and rotational freedom of the left shock absorber body mounting point of the rear suspension of the body-in-white, constraining the displacement and rotational freedom of the right shock absorber body mounting point of the rear suspension of the body-in-white, and applying a predetermined torque (for example, 2000N*M vertical torque) at the left shock absorber body mounting point of the front suspension of the body-in-white in an MPC (Multi-Point Constraint) manner, and applying a predetermined torque (for example, 2000N*M vertical torque) at the right shock absorber body mounting point of the front suspension of the body-in-white in an MPC manner, and under the conditions of the loading method of this torsional stiffness working condition, the torsional stiffness is greater than or equal to the torsional stiffness target value, wherein the application direction of the vertical torque is based on the global coordinate system. The loading method of the chassis attachment point stiffness working condition includes: constraining the position and rotational freedom of the front subframe mounting point, and applying a predetermined force (e.g., 100 N) in the X-axis direction of the chassis attachment point, applying a predetermined force (e.g., 100 N) in the Y-axis direction of the chassis attachment point, and applying a predetermined force (e.g., 100 N) in the Z-axis direction of the chassis attachment point. Under the conditions of this loading method of the chassis attachment point stiffness working condition, the mounting point stiffness is greater than or equal to the mounting point stiffness target value.

[0034] In step S250, a topological function is constructed based on all load-point support reactions, all displacement values, and the load-point support reaction function. With the goal of minimizing the topological function, the topological function is iteratively solved to obtain a relative density output value, which is then used to perform a lightweight design on the front subframe. In one embodiment of the present application, the expression of the topological function is as follows:

[0035]

[0036]

[0037]

[0038] Formula (3) in, represents the weighted flexibility, For the i The relative density variable of the filling unit, represents the weighting coefficient of the collision equivalent static condition, represents the weighting coefficient of the chassis attachment point stiffness case, represents the weighting coefficient of the bending stiffness case, represents the weighting coefficient of the torsional stiffness case, represents the loading point support reaction function, represents the loading point support reaction for the chassis attachment point stiffness case, represents the loading point support reaction for the bending stiffness case, represents the loading point support reaction for the torsional stiffness condition, Indicates the s The displacement value of the target time point, represents the displacement value of the chassis attachment point stiffness case, represents the displacement value of the bending stiffness case, represents the displacement value of the torsional stiffness condition, Indicates The displacement field at a point in time, Indicates the s target time points, represents the stiffness matrix, represents the quality fraction of the design domain, Indicates the number of chassis attachment points.

[0039] In one embodiment of the present application, the process of lightweighting the front subframe using relative density output values ​​includes: reading the relative density output values, generating a density contour map based on the relative density output values; displaying the density contour map; and performing lightweight design on the front subframe with reference to the density contour map. The processes of reading the relative density output values, generating the density contour map based on the relative density output values, and displaying the density contour map can be implemented using advanced finite element post-processing software (HyperView).

[0040] This application fully considers the dynamic nonlinear effects under collision conditions, and establishes a topological function based on the collision equivalent static condition, the chassis attachment point stiffness condition, the bending stiffness condition and the torsional stiffness condition. The topological function is iteratively solved to obtain the relative density output value, avoiding iterative solution through serial optimization model in multiple working conditions, greatly shortening the design cycle, and effectively solving the contradiction between collision energy absorption and vehicle stiffness, improving the accuracy of the relative density output value calculation. At the same time, by converting the nonlinear finite element model into a linear model, the computational complexity of iterative solution of the topological function is greatly reduced, which helps to improve the calculation rate of the relative density output value.

[0041] In one embodiment of the present application, the process of screening the time points in the displacement time function and the time points in the internal energy gradient time function to obtain the target time points includes: According to the displacement screening condition, the displacement values ​​in the displacement-time function are screened to obtain a screened displacement value, and the time point corresponding to the screened displacement value is used as the first screening time point. In one embodiment of the present application, the displacement screening condition includes: selecting a displacement value in the displacement-time function that is greater than or equal to a preset safety threshold, where the preset safety threshold is set based on actual conditions.

[0042] According to the internal energy gradient screening conditions, the internal energy gradient values ​​in the internal energy gradient time function are screened to obtain a screened internal energy gradient value, and the time point corresponding to the screened internal energy gradient value is used as the second screening time point. In one embodiment of the present application, the internal energy gradient screening conditions include: selecting the internal energy gradient maximum point and the point where the internal energy gradient turns from positive to negative. The internal energy gradient maximum point is used to represent the point corresponding to the peak energy absorption rate, and the point where the internal energy gradient turns from positive to negative is used to represent the energy absorption saturation point.

[0043] Based on the internal energy gradient time function, the internal energy scores at the first screening time point and the second screening time point are calculated; based on the internal energy scores and the time point spacing, the first screening time point and the second screening time point are screened to obtain the target time point. In one embodiment of the present application, the expression for the internal energy score is as follows: Formula (4) in, represents the internal energy score, Indicates the i Screening time point, i The screening time point is the first screening time point or the second screening time point, Indicates the first screening time point, represents the weighting factor of the energy absorption rate, represents the weight factor of the accumulated energy, represents the weight factor of the front subframe mounting point displacement penalty term, Represents the attenuation coefficient, which is used to control the attenuation coefficient of the displacement penalty term of the front subframe mounting point. represents the absolute value of the internal energy gradient time function, It represents the internal energy time function obtained by integrating the internal energy gradient time function in the time dimension.

[0044] The expression of the internal energy gradient time function is as follows: Formula (5) in, Indicates the The internal energy gradient value at a time point is Indicates the The internal energy value at a time point, Indicates the After obtaining the internal energy gradient time function, the internal energy gradient time function is input into the Savitzky-Golay filter, and the processed internal energy gradient time function is output to achieve the effect of smoothing the internal energy gradient data with large noise in the internal energy gradient time function and avoiding false detection of extreme points.

[0045] The expression of internal energy time function is as follows: Formula (6) in, represents the internal energy time function, represents the filling element stress, represents the fill element strain tensor, represents the integration domain including all front subframe units, represents the filling unit, Represents the set of all front subframe units.

[0046] In one embodiment of the present application, the first screening time point obtained by screening through the displacement screening condition is a key time point for characterizing exceeding the safety threshold, and the second screening time point obtained by screening through the internal energy gradient screening condition is a key time point for characterizing the energy absorption situation. Furthermore, the first screening time point and the second screening time point are screened by the internal energy score and the time point spacing, which not only greatly reduces the number of target time points, but also helps to reduce the number of time points that need to be calculated, thereby reducing the amount of calculation for iteratively solving the topological function, and thereby improving the calculation rate of the relative density output value. Moreover, the target time point is dynamically selected according to the displacement screening condition, the internal energy gradient screening condition, the internal energy score and the time point spacing, avoiding the technical problems of low calculation efficiency and lack of pertinence caused by intercepting time points at certain step sizes in the nonlinear analysis time history to calculate the equivalent static force.

[0047] In one embodiment of the present application, the process of screening the first screening time point and the second screening time point based on the internal energy score and the time point spacing to obtain the target time point includes: If the time point spacing is less than or equal to a preset distance threshold, and the difference in the internal energy scores between the two screening time points calculated to have a time point spacing is less than or equal to the preset score threshold, then the time point with the smaller internal energy score between the two screening time points calculated to have a time point spacing is deleted. In one embodiment of the present application, the preset distance threshold is set based on actual conditions, and the preset score threshold is set based on actual conditions. By deleting the time point with the smaller internal energy score between the two screening time points calculated to have a time point spacing when the time point spacing is less than or equal to the preset distance threshold, and the difference in the internal energy scores between the two screening time points calculated to have a time point spacing is less than or equal to the preset score threshold, this helps to further reduce the number of time points and retain time points with higher scores (i.e., stronger features).

[0048] The time point remaining after deleting the first screening time point and the second screening time point is used as the update time point, or the first screening time point and the second screening time point are combined to obtain a first combined time point, and the first combined time point is used as the update time point. In one embodiment of the present application, if no time point is deleted from the first screening time point and the second screening time point, the first combined time point is used as the update time point; if a time point is deleted from the first screening time point and the second screening time point, the time point remaining after deleting the first screening time point and the second screening time point is used as the update time point.

[0049] The internal energy gradient time function is integrated along the time dimension to obtain the internal energy time function; based on the comparison result of the internal energy gradient standard deviation at each time point and the preset standard deviation threshold, the internal energy time function is divided into the elastic stage, the plastic development stage, and the stable stage. In one embodiment of the present application, the preset standard deviation threshold is set according to the actual situation, and the calculation formula of the internal energy gradient standard deviation is as follows: Formula (7) in, express The standard deviation of the internal energy gradient at a time point, Indicates the The internal energy gradient value at a time point is represents the mean value of the internal energy gradient, Indicates the number of time points.

[0050] In some embodiments of the present application, the standard deviation of the internal energy gradient is calculated by sliding in ascending order of time t starting from time t=0. The calculation formula of the standard deviation of the internal energy gradient is shown in Formula (7), and the window size is N (that is, the number of time points in a window), which is used to quantify the fluctuation of the internal energy gradient. The process of dividing the internal energy time function into the elastic stage, the plastic development stage and the stable stage according to the comparison results of the internal energy gradient standard deviation at each time point and the preset standard deviation threshold includes: starting from time t=0, the internal energy gradient standard deviation calculated at different time points is compared with the preset standard deviation threshold from front to back. If the internal energy gradient standard deviation is less than the preset standard deviation threshold, the time point corresponding to the internal energy gradient standard deviation belongs to the elastic stage; if the internal energy gradient standard deviation is equal to the preset standard deviation threshold, the elastic stage ends and the time point corresponding to the internal energy gradient standard deviation is used as the starting point of the plastic development stage; starting from the starting point of the plastic development stage, the internal energy gradient standard deviation calculated at different time points is compared with the preset standard deviation threshold from front to back. If the internal energy gradient standard deviation is greater than the preset standard deviation threshold, the time point corresponding to the internal energy gradient standard deviation belongs to the plastic development stage; if the internal energy gradient standard deviation is equal to the preset standard deviation threshold, the plastic development stage ends and the time point corresponding to the internal energy gradient standard deviation is used as the starting point of the stable stage, and the time from the starting point of the stable stage to the end point of the internal energy time function is used as the stable stage. The elastic stage is used to characterize the linear growth of internal energy, the plastic development stage is used to characterize the fluctuation and increase of internal energy gradient, and the stable stage is used to characterize the approach of internal energy to saturation.

[0051] The update time point is compared with the time range of the elastic stage to obtain the elastic stage time point; the update time point is compared with the time range of the plastic development stage to obtain the plastic development stage time point; the update time point is compared with the time range of the stable stage to obtain the stable stage time point. In one embodiment of the present application, if the update time point falls within the time range of the elastic stage, it is used as the elastic stage time point; if the update time point falls within the time range of the plastic development stage, it is used as the plastic development stage time point; if the update time point falls within the time range of the stable stage, it is used as the stable stage time point.

[0052] According to the internal energy scores of the elastic phase time points, a first preset number of time points are selected from the elastic phase time points; according to the internal energy scores of the plastic development phase time points, a second preset number of time points are selected from the plastic development phase time points; and according to the internal energy scores of the stable phase time points, a third preset number of time points are selected from the stable phase time points. In one embodiment of the present application, the first preset number, the second preset number, and the third preset number can be the same or different, and the first preset number, the second preset number, and the third preset number are all set according to actual conditions. After obtaining the elastic phase time points, the plastic development phase time points, and the stable phase time points, a first preset number of time points with larger internal energy scores are selected from the elastic phase time points, a second preset number of time points with larger internal energy scores are selected from the plastic development phase time points, and a third preset number of time points with larger internal energy scores are selected from the stable phase time points. The above process further implements the screening of time points with larger internal energy scores among the time points, and retains time points in the elastic phase, the plastic development phase, and the stable phase, ensuring that the distribution of time points can cover the energy absorption mechanisms of different stages.

[0053] The first preset number of time points, the second preset number of time points, and the third preset number of time points are combined to obtain a second combination of time points, and the second combination of time points is used as the target time point. In one embodiment of the present application, the first preset number of time points, the second preset number of time points, and the third preset number of time points are time points with the largest internal energy scores at different stages, and using the second combination of time points as the target time point can better reflect the internal energy characteristics and energy absorption mechanisms of different stages.

[0054] In one embodiment of the present application, before obtaining a nonlinear finite element model for performing a crash simulation on the entire vehicle, the front subframe lightweight design method further includes: Obtaining front subframe envelope data. In one embodiment of the present application, the front subframe envelope data is derived from a front subframe unit in a preset collision finite element model. The preset collision finite element model can be a frontal 100% overlap rigid wall collision finite element model or a frontal 40% overlap rigid wall collision finite element model that complies with GB11551-2014.

[0055] Based on the front subframe envelope data, a front subframe spatial region is established and filled with filling cells to obtain front subframe spatial region units. In one embodiment of the present application, the attribute information of the filling cells is consistent with the attribute information of the front subframe units, and the attribute information of the filling cells includes the material type, relative density, elastic modulus, stress, thermal conductivity, etc. The filling cells can be first-order hexahedral cells, tetrahedral cells, quadrangular prisms, pentahedrons, etc.

[0056] A nonlinear finite element model is obtained by replacing the front subframe unit with a front subframe spatial region unit and configuring the connection and positional relationships between the front subframe and pre-set components. In one embodiment of the present application, the pre-set components include a body-in-white, chassis components, suspension brackets, and swing arms. The connection and positional relationships between the front subframe and the pre-set components must ensure that there is no interference or collision between the front subframe and the pre-set components, and that the front subframe and the pre-set components function properly.

[0057] In one embodiment of the present application, with the goal of minimizing the topology function, the process of iteratively solving the topology function includes: Obtaining the current relative density value of the filling unit. In one embodiment of the present application, the current relative density value can be obtained by presetting.

[0058] The current relative density value is input into the topological function to obtain the current weighted flexibility, and the number of iterations is counted. In one embodiment of the present application, after the first iteration, the number of iterations is set to 1.

[0059] The relative density variable is used as the design variable, and the topological function is derived in the design variable dimension to obtain the gradient function of the design variable. In one embodiment of the present application, the expression of the gradient function is as follows: = Formula (8) in, represents the gradient function of the design variable, represents the weighted flexibility, represents the design variable (i.e., relative density variable).

[0060] The current relative density value is input into the gradient function to obtain the initial sensitivity of the design variable; based on the initial sensitivity, the current relative density value is updated to obtain an updated relative density value; the updated relative density value is input into the topology function to obtain an updated weighted flexibility, and the number of iterations is updated. In one embodiment of the present application, the gradient descent method is used to update the design variable, and the calculation formula for the updated relative density value is as follows: Formula (9) in, Indicates the iteration step is design variables (e.g., updating relative density values), Indicates the iteration step is design variables (e.g., current relative density value), represents the step length, Indicates the initial sensitivity of the design variable (that is, the initial sensitivity obtained when the current relative density value is input).

[0061] The flexibility change between the current weighted flexibility and the updated weighted flexibility is calculated, and the density change between the updated relative density value and the current relative density value is calculated. In one embodiment of the present application, the flexibility change and the density change can be used as factors to determine whether the topology function is iteratively stopped.

[0062] According to the comparison result of the flexibility change amount and the preset flexibility change amount threshold, the comparison result of the density value change amount and the preset density value change amount threshold, and the comparison result of the updated number of iterations and the preset number of iterations threshold, the number of iterations of the topological function and the relative density output value are determined. In one embodiment of the present application, the preset flexibility change amount threshold, the preset density value change amount threshold and the preset number of iterations threshold are all set according to actual conditions. According to the comparison result of the flexibility change amount and the preset flexibility change amount threshold, the comparison result of the density value change amount and the preset density value change amount threshold, and the comparison result of the updated number of iterations and the preset number of iterations threshold, the process of determining the number of iterations of the topological function and the relative density output value includes: if the flexibility change amount is less than the preset flexibility change amount threshold, or the density value change amount is less than the preset density value change amount threshold, or the updated number of iterations is greater than the preset number of iterations threshold, then stop iterating and solving the topological function, and use the updated relative density value as the density output value; if the flexibility change amount is greater than or equal to the preset flexibility change amount threshold, or the density value change amount is greater than or equal to the preset density value change amount ... If the updated relative density value is less than or equal to the preset iteration threshold, the updated relative density value is input into the gradient function to obtain the update sensitivity of the design variable. Based on the updated sensitivity, the updated relative density value and the updated weighted flexibility are continuously updated to obtain the updated flexibility change and the updated density value change. The updated number of iterations is continuously updated until the updated flexibility change is less than the preset flexibility change threshold, or the updated density value change is less than the preset density value change threshold, or the updated number of iterations is greater than the preset iteration threshold. Then, the iterative solution of the topological function is stopped, and the updated relative density value is used as the density output value.

[0063] In one embodiment of the present application, the dynamic nonlinear effects under collision conditions are fully taken into account, and a topological function is established based on the collision equivalent static condition, the chassis attachment point stiffness condition, the bending stiffness condition and the torsional stiffness condition. The topological function is iteratively solved to obtain the relative density output value, avoiding iterative solution through serial optimization model in multiple working condition performance, solving the problem of multidisciplinary performance coupling, greatly shortening the design cycle, and effectively resolving the contradiction between collision energy absorption and vehicle stiffness, thereby improving the accuracy of relative density output value calculation. At the same time, by converting the nonlinear finite element model into a linear model, the computational complexity of iterative solution of the topological function is greatly reduced, which helps to improve the calculation rate of the relative density output value; dynamic selection is performed according to displacement screening conditions, internal energy gradient screening conditions, internal energy score and time point spacing, avoiding the technical problems of low computational efficiency and lack of pertinence caused by intercepting time points at certain step lengths in the nonlinear analysis time history to calculate the equivalent static force.

[0064] Figure 3is a flow chart of a front subframe lightweight design method shown in another exemplary embodiment of the present application. Figure 3 The lightweight design method of the front subframe includes: (1) obtaining the front subframe envelope data: the front subframe envelope data is derived from the GB 11551-2014 stipulates the frontal 100% overlapping rigid wall collision finite element model; (2) Design space definition: Based on the front subframe envelope data, the front subframe space area is established, and the front subframe space area is filled with filling units to obtain the front subframe space area unit; (3) Obtaining a nonlinear finite element model: The front subframe unit is replaced by the front subframe space area unit, and the connection relationship and position relationship between the front subframe and the preset components are configured to obtain a nonlinear finite element model; (4) Nonlinear solution: The nonlinear finite element model is solved to obtain the displacement time function of the front subframe installation point and the internal energy gradient time function of the filling unit; (5) Time point screening: The time points in the displacement time function and the time points in the internal energy gradient time function are screened to obtain the target time point; (6) Equivalent static load calculation: According to the displacement field at the target time point, the unit stiffness matrix of the filling unit, and the relative density variable of the filling unit, the loading point support reaction function of the collision equivalent static working condition is determined; and based on According to the target time point and the displacement-time function, the displacement value of the equivalent static working condition of the collision is determined; (7) Based on the front subframe data and the body-in-white data, a collision linear model is generated; the collision linear model is used to characterize the loading point support reaction and displacement value generated under the chassis attachment point stiffness working condition, the loading point support reaction and displacement value generated under the bending stiffness working condition, and the loading point support reaction and displacement value generated under the torsional stiffness working condition; (8) Topology optimization: Based on all loading point support reactions, all displacement values ​​and loading point support reaction functions, a topology function is constructed; (9) Iteratively solve the topology function: determine whether the iteration process is completed. If the iteration process is completed, the density contour cloud map is output; if the iteration process is not completed, the design variables are updated until the calculated flexibility change after the update is less than the preset flexibility change threshold, or the calculated density value change after the update is less than the preset density value change threshold, or the number of iterations after the update is greater than the preset iteration number threshold, the iteration process is stopped, and the density contour cloud map is output.

[0065] Figure 4 is a schematic diagram of the front subframe space area shown in an exemplary embodiment of the present application. Figure 4 In the model, the front subframe space region is constructed according to the front subframe envelope data, and the front subframe space region is filled with first-order hexahedral elements.

[0066] Figure 5 is a schematic diagram of an internal energy time function shown in an exemplary embodiment of the present application. Figure 5In the figure, the horizontal axis is time in seconds, and the vertical axis is energy in kilojoules. Within 0-0.02s, the internal energy increases linearly with time. Within 0.02-0.06s, the internal energy continues to rise. Within 0.06s-0.12s, the internal energy approaches saturation.

[0067] Figure 6 is a schematic diagram of an internal energy gradient time function shown in an exemplary embodiment of the present application. Figure 6 In the figure, the horizontal axis is time in seconds, the vertical axis is energy gradient in kilojoules per second, the maximum point of internal energy gradient represents the point corresponding to the peak value of energy absorption rate, and the point where the internal energy gradient turns from positive to negative is used to represent the energy absorption saturation point.

[0068] Figure 7 is a relative density contour cloud diagram of the front subframe space area shown in an exemplary embodiment of the present application. Figure 7 In the graph, different color depths represent different relative density values, thus representing different materials.

[0069] This application establishes a topological function and performs iterative optimization based on the collision equivalent static working condition, the chassis attachment point stiffness working condition, the bending stiffness working condition and the torsional stiffness working condition, accurately identifies the force transmission path, eliminates redundant materials, achieves subframe weight reduction while meeting the needs of multiple working conditions, effectively resolves the contradiction between collision energy absorption and vehicle stiffness, and avoids local over-design problems caused by iterative optimization through serial optimization models in multiple working condition performance; compared with calculating the equivalent static force by intercepting time points at certain step lengths, the dynamic selection of time points greatly reduces the single iterative calculation time; the collision load distribution is more reasonable, ensuring that the collision energy is dissipated along the preset path, reducing the intrusion into the passenger compartment and improving safety; in addition, it can also bring about energy conservation and emission reduction effects due to the reduction in material cost of a single front subframe and the lighter weight of the entire vehicle.

[0070] The following describes an apparatus embodiment of the present application, which can be used to execute the data view configuration method in the above-mentioned embodiment of the present application. For details not disclosed in the apparatus embodiment of the present application, please refer to the above-mentioned embodiment of the data view configuration method of the present application.

[0071] Figure 8 This is a block diagram of a front subframe lightweight design device shown in an exemplary embodiment of the present application. The device can be applied to Figure 1 The implementation environment shown is specifically configured in the computer device 102. The apparatus may also be applicable to other exemplary implementation environments and specifically configured in other devices. This embodiment does not limit the implementation environment to which the apparatus is applicable.

[0072] like Figure 8 As shown, the exemplary front subframe lightweight design device 800 includes: The data acquisition module 801 is used to obtain a nonlinear finite element model for performing collision simulation on the entire vehicle.

[0073] The time point screening module 802 is used to solve the nonlinear finite element model to obtain the displacement time function of the front subframe mounting point and the internal energy gradient time function of the filling unit; and to screen the time points in the displacement time function and the internal energy gradient time function to obtain the target time point.

[0074] The static working condition calculation module 803 is used to determine the loading point support reaction function of the collision equivalent static working condition based on the displacement field at the target time point, the unit stiffness matrix of the filling unit, and the relative density variable of the filling unit; and determine the displacement value of the collision equivalent static working condition based on the target time point and the displacement time function.

[0075] The model conversion module 804 is used to generate a collision linear model based on the front subframe data and the body-in-white data.

[0076] The function solving module 805 is used to construct a topological function based on all loading point support reactions, all displacement values ​​and loading point support reaction functions, and iteratively solve the topological function with the goal of minimizing the topological function to obtain a relative density output value, so as to perform lightweight design on the front subframe through the relative density output value.

[0077] In one embodiment of the present application, the nonlinear finite element model includes front subframe data and body-in-white data. The front subframe data is determined by the attribute information of filling cells. The filling cells are used to fill the spatial region of the front subframe. The attribute information of the filling cells includes the material type, relative density, elastic modulus, stress, thermal conductivity, etc. The filling cells can be first-order hexahedral cells, tetrahedral cells, quadrangular prisms, pentahedrons, etc.

[0078] In one embodiment of the present application, a nonlinear finite element model is solved using nonlinear finite element analysis software, the nonlinear finite element analysis software being LS-DYNA (Livermore Software Technology Corporation-DYNA). The process of screening time points in a displacement time function and a time point in an internal energy gradient time function to obtain a target time point includes: screening the displacement values ​​in the displacement time function according to a displacement screening condition to obtain a screened displacement value, and using the time point corresponding to the screened displacement value as a first screening time point; screening the internal energy gradient values ​​in the internal energy gradient time function according to an internal energy gradient screening condition to obtain a screened internal energy gradient value, and using the time point corresponding to the screened internal energy gradient value as a second screening time point; calculating internal energy scores at the first screening time point and the second screening time point based on the internal energy gradient time function; and screening the first screening time point and the second screening time point based on the internal energy score and the time point spacing to obtain the target time point.

[0079] In one embodiment of the present application, once a displacement-time function is obtained, the target time point is input into the displacement-time function to obtain the displacement value of the collision equivalent static working condition. The expression for the loading point support reaction function is shown in Formula (1), and the expression for the stiffness matrix is ​​shown in Formula (2).

[0080] In one embodiment of the present application, a linear collision model is used to characterize the load-point support reaction force and displacement values ​​generated under a chassis attachment point stiffness condition, the load-point support reaction force and displacement values ​​generated under a bending stiffness condition, and the load-point support reaction force and displacement values ​​generated under a torsional stiffness condition. The loading method for the bending stiffness condition includes: constraining the displacement and rotational degrees of freedom of the front suspension shock absorber mounting point of the body-in-white, constraining the displacement and rotational degrees of freedom of the rear suspension shock absorber mounting point of the body-in-white, and applying a predetermined force (e.g., 2000N) vertically downward to the left side of the midpoint of the door sill and a predetermined force (e.g., 2000N) vertically downward to the right side of the midpoint of the door sill, and under the conditions of this loading method for the bending stiffness condition, the bending stiffness is greater than or equal to the target bending stiffness value. The loading method of the torsional stiffness working condition includes: constraining the displacement and rotational freedom of the left shock absorber body mounting point of the rear suspension of the body-in-white, constraining the displacement and rotational freedom of the right shock absorber body mounting point of the rear suspension of the body-in-white, and applying a predetermined torque (for example, 2000N*M vertical torque) at the left shock absorber body mounting point of the front suspension of the body-in-white in an MPC (Multi-Point Constraint) manner, and applying a predetermined torque (for example, 2000N*M vertical torque) at the right shock absorber body mounting point of the front suspension of the body-in-white in an MPC manner, and under the conditions of the loading method of this torsional stiffness working condition, the torsional stiffness is greater than or equal to the torsional stiffness target value, wherein the application direction of the vertical torque is based on the global coordinate system. The loading method of the chassis attachment point stiffness working condition includes: constraining the position and rotational freedom of the front subframe mounting point, and applying a predetermined force (e.g., 100 N) in the X-axis direction of the chassis attachment point, applying a predetermined force (e.g., 100 N) in the Y-axis direction of the chassis attachment point, and applying a predetermined force (e.g., 100 N) in the Z-axis direction of the chassis attachment point. Under the conditions of this loading method of the chassis attachment point stiffness working condition, the mounting point stiffness is greater than or equal to the mounting point stiffness target value.

[0081] In one embodiment of the present application, the expression of the topological function is shown in Formula (3). The process of lightweighting the front subframe using the relative density output value includes: reading the relative density output value, forming a density contour cloud map based on the relative density output value; displaying the density contour cloud map; and lightweighting the front subframe with reference to the density contour cloud map. The process of reading the relative density output value, forming a density contour cloud map based on the relative density output value, and displaying the density contour cloud map can be implemented using advanced finite element post-processing software (HyperView).

[0082] This application fully considers the dynamic nonlinear effects under collision conditions, and establishes a topological function based on the collision equivalent static condition, the chassis attachment point stiffness condition, the bending stiffness condition and the torsional stiffness condition. The topological function is iteratively solved to obtain the relative density output value, avoiding iterative solution through serial optimization model in multiple working conditions, greatly shortening the design cycle, and effectively solving the contradiction between collision energy absorption and vehicle stiffness, improving the accuracy of the relative density output value calculation. At the same time, by converting the nonlinear finite element model into a linear model, the computational complexity of iterative solution of the topological function is greatly reduced, which helps to improve the calculation rate of the relative density output value.

[0083] It should be noted that the front subframe lightweight design device provided in the above-mentioned embodiment and the front subframe lightweight design method provided in the above-mentioned embodiment are based on the same concept. The specific manner in which the various modules and units perform their operations has been described in detail in the method embodiments and will not be repeated here. In actual applications, the front subframe lightweight design device provided in the above-mentioned embodiment can, as needed, allocate the aforementioned functions to different functional modules, i.e., divide the internal structure of the device into different functional modules to perform all or part of the functions described above, and this is not a limitation herein.

[0084] An embodiment of the present application also provides an electronic device, comprising: one or more processors; a storage device for storing one or more programs, wherein when the one or more programs are executed by the one or more processors, the electronic device implements the front subframe lightweight design method provided in the above-mentioned embodiments.

[0085] Figure 9 The following is a schematic diagram showing the structure of a computer system suitable for implementing an electronic device according to an embodiment of the present application. Figure 9 The computer system 900 of the electronic device shown is only an example and should not bring any limitation to the functions and scope of use of the embodiments of the present application.

[0086] like Figure 9As shown, computer system 900 includes a central processing unit (CPU) 901, which can perform various appropriate actions and processes, such as executing the methods described in the above embodiments, based on programs stored in read-only memory (ROM) 902 or programs loaded from storage 908 into random access memory (RAM) 903. RAM 903 also stores various programs and data required for system operation. CPU 901, ROM 902, and RAM 903 are interconnected via a bus 904. An input / output (I / O) interface 905 is also connected to bus 904.

[0087] The following components are connected to the I / O interface 905: an input section 906 including a keyboard, a mouse, and the like; an output section 907 including devices such as a cathode ray tube (CRT), a liquid crystal display (LCD), and speakers; a storage section 908 including devices such as a hard disk; and a communication section 909 including a network interface card such as a LAN (Local Area Network) card or a modem. The communication section 909 performs communication processing via a network such as the Internet. A drive 910 is also connected to the I / O interface 905 as needed. Removable media 911, such as a magnetic disk, an optical disk, a magneto-optical disk, or a semiconductor memory, is installed in the drive 910 as needed, so that computer programs read from the removable media can be installed in the storage section 908 as needed.

[0088] In particular, according to embodiments of the present application, the processes described above with reference to the flowcharts can be implemented as computer software programs. For example, embodiments of the present application include a computer program product comprising a computer program carried on a computer-readable medium, the computer program including a computer program for executing the methods illustrated in the flowcharts. In such embodiments, the computer program can be downloaded and installed from a network via the communication section 909 and / or installed from removable media 911. When executed by the central processing unit (CPU) 901, the computer program performs the various functions defined in the system of the present application.

[0089] It should be noted that the computer-readable medium described in the embodiments of this application may be a computer-readable signal medium or a computer-readable storage medium, or any combination thereof. A computer-readable storage medium may, for example, be an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device, or component, or any combination thereof. More specific examples of computer-readable storage media may include, but are not limited to, an electrical connection having one or more wires, a portable computer disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM), flash memory, optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination thereof. In this application, a computer-readable signal medium may include a data signal propagated in baseband or as part of a carrier wave, carrying a computer-readable computer program. This propagated data signal may take a variety of forms, including, but not limited to, an electromagnetic signal, an optical signal, or any suitable combination thereof. A computer-readable signal medium may also be any computer-readable medium other than a computer-readable storage medium that can transmit, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device. A computer program embodied on a computer-readable medium may be transmitted using any suitable medium, including but not limited to wireless, wired, or any suitable combination thereof.

[0090] The flowcharts and block diagrams in the accompanying drawings illustrate the possible implementation architecture, functions and operations of the systems, methods and computer program products according to various embodiments of the present application. Among them, each box in the flowchart or block diagram can represent a module, program segment, or part of the code, and the above-mentioned module, program segment, or part of the code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in an order different from that marked in the accompanying drawings. For example, two boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram or flowchart, and the combination of boxes in the block diagram or flowchart, can be implemented with a dedicated hardware-based system that performs the specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0091] The units involved in the embodiments described in this application may be implemented by software or hardware, and the units described may also be set in a processor. In some cases, the names of these units do not constitute limitations on the units themselves.

[0092] Another aspect of the present application provides a vehicle including the front subframe lightweight design method described in the above embodiments. The vehicle may include the electronic device described in the above embodiments, or may exist independently without the electronic device described in the above embodiments being incorporated into the vehicle.

[0093] It should be noted that, although several modules or units of the device for action execution are mentioned in the above detailed description, this division is not mandatory. In fact, according to the embodiment of the application, the features and functions of two or more modules or units described above can be concretized in one module or unit. On the contrary, the features and functions of one module or unit described above can be further divided into multiple modules or units to be concretized.

[0094] Through the description of the above embodiments, it is easy for those skilled in the art to understand that the example embodiments described herein can be implemented by software or by combining software with necessary hardware. Therefore, the technical solution according to the embodiments of the present application can be embodied in the form of a software product, which can be stored in a non-volatile storage medium (which can be a CD-ROM, a USB flash drive, a mobile hard disk, etc.) or on a network, and includes several instructions to enable a computing device (which can be a personal computer, a server, a touch terminal, or a network device, etc.) to execute the method according to the embodiments of the present application.

[0095] Those skilled in the art will readily conceive of other embodiments of the present application after considering the specification and practicing the embodiments disclosed herein. This application is intended to cover any variations, uses, or adaptations of the present application that follow the general principles of this application and include common knowledge or customary techniques in the art that are not disclosed herein.

[0096] It should be understood that the above content is only a preferred exemplary embodiment of the present application and is not intended to limit the implementation scheme of the present application. Ordinary technicians in this field can easily make corresponding changes or modifications based on the main concept and spirit of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection required by the claims.

Claims

1. A lightweight design method for a front subframe, characterized in that: The method comprises: Obtaining a nonlinear finite element model for performing a crash simulation on the entire vehicle, the nonlinear finite element model including front subframe data and body-in-white data; the front subframe data is determined by attribute information of a filling unit; the filling unit is used to fill a spatial area of ​​the front subframe; Solving the nonlinear finite element model to obtain a displacement time function of the front subframe mounting point and an internal energy gradient time function of the filling unit; and screening time points in the displacement time function and the internal energy gradient time function to obtain target time points; Determine a loading point support reaction function of a collision equivalent static working condition based on the displacement field at the target time point, the unit stiffness matrix of the filling unit, and the relative density variable of the filling unit; and determine a displacement value of the collision equivalent static working condition based on the target time point and the displacement time function; generating a collision linear model based on the front subframe data and the body-in-white data; the collision linear model is used to characterize the load point support reaction force and displacement value generated under the chassis attachment point stiffness working condition, the load point support reaction force and displacement value generated under the bending stiffness working condition, and the load point support reaction force and displacement value generated under the torsional stiffness working condition; Based on all loading point support reactions, all displacement values ​​and the loading point support reaction function, a topological function is constructed. With the goal of minimizing the topological function, the topological function is iteratively solved to obtain a relative density output value, so as to perform a lightweight design on the front subframe through the relative density output value.

2. The front subframe lightweight design method according to claim 1, characterized in that: The process of screening the time points in the displacement time function and the time points in the internal energy gradient time function to obtain the target time points includes: According to a displacement screening condition, the displacement values ​​in the displacement-time function are screened to obtain a screened displacement value, and a time point corresponding to the screened displacement value is used as a first screening time point; the displacement screening condition includes: selecting a displacement value in the displacement-time function that is greater than or equal to a preset safety threshold; According to the internal energy gradient screening condition, the internal energy gradient value in the internal energy gradient time function is screened to obtain a screened internal energy gradient value, and the time point corresponding to the screened internal energy gradient value is used as the second screening time point; the internal energy gradient screening condition includes: selecting the internal energy gradient maximum point and the point where the internal energy gradient turns from positive to negative; Based on the internal energy gradient time function, the internal energy scores at the first screening time point and the second screening time point are calculated; based on the internal energy scores and the time point spacing, the first screening time point and the second screening time point are screened to obtain the target time point.

3. The front subframe lightweight design method according to claim 2, characterized in that: The calculation formula of the internal energy score is include: ， in, represents the internal energy score, Indicates the i Screening time point, i The screening time point is the first screening time point or the second screening time point, Indicates the first screening time point, represents the weighting factor of the energy absorption rate, represents the weight factor of the accumulated energy, represents the weight factor of the front subframe mounting point displacement penalty term, Represents the attenuation coefficient, which is used to control the attenuation coefficient of the displacement penalty term of the front subframe mounting point. represents the absolute value of the internal energy gradient time function, It represents the internal energy time function obtained by integrating the internal energy gradient time function in the time dimension.

4. The front subframe lightweight design method according to claim 2, characterized in that: The process of screening the first screening time point and the second screening time point based on the internal energy score and the time point interval to obtain the target time point includes: If the time point interval is less than or equal to the preset distance threshold, and the difference between the internal energy scores of the two screening time points calculated to obtain the time point interval is less than or equal to the preset score threshold, then the time point with the smaller internal energy score between the two screening time points calculated to obtain the time point interval is deleted; The remaining time point after deleting the first screening time point and the second screening time point is used as the update time point, or the first screening time point and the second screening time point are combined to obtain a first combined time point, and the first combined time point is used as the update time point; Integrating the internal energy gradient time function according to the time dimension to obtain the internal energy time function; dividing the internal energy time function into an elastic stage, a plastic development stage, and a stable stage according to a comparison result of the internal energy gradient standard deviation at each time point and a preset standard deviation threshold; Comparing the update time point with the time range of the elastic stage to obtain the elastic stage time point; comparing the update time point with the time range of the plastic development stage to obtain the plastic development stage time point; comparing the update time point with the time range of the stable stage to obtain the stable stage time point; According to the internal energy scores of the elastic stage time points, a first preset number of time points are selected from the elastic stage time points; according to the internal energy scores of the plastic development stage time points, a second preset number of time points are selected from the plastic development stage time points; according to the internal energy scores of the stable stage time points, a third preset number of time points are selected from the stable stage time points; The first preset number of time points, the second preset number of time points, and the third preset number of time points are combined to obtain second combined time points, and the second combined time points are used as the target time points.

5. The front subframe lightweight design method according to any one of claims 1 to 4, characterized in that: Before obtaining a nonlinear finite element model for performing collision simulation on the entire vehicle, the method further includes: Acquiring front subframe envelope data; the front subframe envelope data is derived from a front subframe unit in a preset collision finite element model; Based on the front subframe envelope data, the front subframe space region is established, and the front subframe space region is filled by the filling unit to obtain a front subframe space region unit; the attribute information of the filling unit is consistent with the attribute information of the front subframe unit; The nonlinear finite element model is obtained by replacing the front subframe unit with the front subframe space area unit and configuring the connection relationship and position relationship between the front subframe and preset components; the preset components include a body-in-white, a chassis component and a suspension bracket.

6. The front subframe lightweight design method according to any one of claims 1 to 4, characterized in that: The expression of the loading point support reaction function includes: ， in, represents the loading point support reaction function, Indicates The displacement field at a point in time, Indicates the s target time points, represents the stiffness matrix; The expression of the stiffness matrix includes: ， in, represents the stiffness matrix, Indicates the i The relative density variable of the filling unit, p represents the penalty factor, Indicates the i The element stiffness matrix of the infill element.

7. The front subframe lightweight design method according to any one of claims 1 to 4, characterized in that: The process of iteratively solving the topological function with the goal of minimizing the topological function includes: Obtaining a current relative density value of the filling unit; Inputting the current relative density value into the topological function to obtain the current weighted flexibility, and counting the number of iterations; Taking the relative density variable as a design variable, and deriving the topological function in the dimension of the design variable to obtain a gradient function of the design variable; Inputting the current relative density value into the gradient function to obtain the initial sensitivity of the design variable; and updating the current relative density value based on the initial sensitivity to obtain an updated relative density value; inputting the updated relative density value into the topology function to obtain an updated weighted flexibility, and updating the number of iterations; Calculating a change in flexibility between the current weighted flexibility and the updated weighted flexibility, and calculating a change in density between the updated relative density value and the current relative density value; The number of iterations of the topological function and the relative density output value are determined based on the comparison results of the flexibility change and the preset flexibility change threshold, the comparison results of the density value change and the preset density value change threshold, and the comparison results of the updated number of iterations and the preset iteration number threshold.

8. The front subframe lightweight design method according to any one of claims 1 to 4, characterized in that: The expression of the topological function includes: ， in, represents the weighted flexibility, For the i The relative density variable of the filling unit, represents the weighting coefficient of the collision equivalent static condition, represents the weighting coefficient of the chassis attachment point stiffness case, represents the weighting coefficient of the bending stiffness case, represents the weighting coefficient of the torsional stiffness case, represents the loading point support reaction function, represents the loading point support reaction for the chassis attachment point stiffness case, represents the loading point support reaction for the bending stiffness case, represents the loading point support reaction for the torsional stiffness condition, Indicates the s The displacement value of the target time point, represents the displacement value of the chassis attachment point stiffness case, represents the displacement value of the bending stiffness case, represents the displacement value of the torsional stiffness condition, Indicates The displacement field at a point in time, Indicates the s target time points, represents the stiffness matrix, represents the quality fraction of the design domain, Indicates the number of chassis attachment points.

9. A front subframe lightweight design device, characterized in that: The device comprises: a data acquisition module, configured to acquire a nonlinear finite element model for performing crash simulation on the entire vehicle, the nonlinear finite element model including front subframe data and body-in-white data; the front subframe data being determined by attribute information of a filling unit; the filling unit being configured to fill a spatial region of the front subframe; a time point screening module, configured to solve the nonlinear finite element model to obtain a displacement time function of the front subframe mounting point and an internal energy gradient time function of the filling unit; and to screen the time points in the displacement time function and the internal energy gradient time function to obtain a target time point; a static working condition calculation module, configured to determine a loading point support reaction function of a collision equivalent static working condition based on the displacement field at the target time point, the unit stiffness matrix of the filling unit, and the relative density variable of the filling unit; and to determine a displacement value of the collision equivalent static working condition based on the target time point and the displacement time function; a model conversion module for generating a collision linear model based on the front subframe data and the body-in-white data; the collision linear model is used to characterize the loading point support reaction force and displacement value generated under the chassis attachment point stiffness working condition, the loading point support reaction force and displacement value generated under the bending stiffness working condition, and the loading point support reaction force and displacement value generated under the torsional stiffness working condition; A function solving module is used to construct a topological function based on all loading point support reactions, all displacement values ​​and the loading point support reaction function, and iteratively solve the topological function with the goal of minimizing the topological function to obtain a relative density output value, so as to perform a lightweight design on the front subframe through the relative density output value.

10. A vehicle, characterized in that: The vehicle includes the front subframe lightweight design method according to any one of claims 1 to 8.

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