Automotive component design method, device and program, and automotive component manufacturing method

Abstract

To provide an automotive component design method, a device and a program for designing an automotive component that receives a compressive load in a longitudinal direction during an automotive collision so as to improve collision performance, and to provide an automotive component manufacturing method.SOLUTION: An automotive component design method comprises: obtaining an automotive component model that models an automotive component that receives a compressive load in a longitudinal direction during an automotive collision (S1); setting a design space for a to-be-designed portion, which is a portion to be designed (S3); generating a to-be-designed-portion model by modeling the set design space with shell elements and / or solid elements (S5); setting, in the automotive component model, an objective function that maximizes the buckling load of the primary buckling mode obtained by linear buckling analysis (S7); performing optimization analysis to find the optimal shape of the to-be-designed-portion model that satisfies the set objective function (S9); and determining the shape of the to-be-designed portion on the basis of the optimal shape of the to-be-designed-portion model (S11).SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method, an apparatus, and a program for designing an automobile part so as to improve the collision performance of an automobile part that receives a compressive load in the longitudinal direction during an automobile collision. Furthermore, the present invention relates to a method for manufacturing an automobile part so as to improve the collision performance of the automobile part that receives a compressive load in the longitudinal direction during an automobile collision. [Background technology]

[0002] While there is an increasing demand for improved collision performance of automobile bodies, there is also a need to reduce the weight of automobile bodies in order to reduce CO2 emissions. In order to meet these demands simultaneously, it is important to design automobile parts with improved collision performance while increasing the strength and thinning of the materials (e.g., steel plates) used in the automobile body.

[0003] The knowledge accumulated over many years has been extremely useful in designing automobile bodies and automobile parts with consideration for collision performance. However, electric vehicles are equipped with large-capacity batteries, so space must be secured for them, and their body frame structure is significantly different from that of conventional gasoline-powered vehicles. In addition, it is also necessary to consider collision protection for these batteries. And as electric vehicles become more widespread, there is a greater demand than ever before for methods to efficiently design automobile bodies and automobile parts.

[0004] As a technique for efficiently designing a high-performance automobile body, for example, Patent Document 1 discloses an optimization method for finding the optimal shape of a part of a structural model (vehicle body) using a computer. In this method, a design space is first set for the part of the vehicle body to be optimized, and load conditions and constraint conditions to be applied to the vehicle body, as well as objective conditions (corresponding to the "objective function" in this application; hereinafter referred to as the objective function) and constraint conditions related to vehicle body performance such as rigidity and weight are set. Then, under the set load conditions and constraint conditions, an optimization analysis process is performed to delete unnecessary parts in the design space so as to satisfy the objective function and constraint conditions, thereby finding the optimal shape of the part of the vehicle body. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 5585672 Summary of the Invention [Problem to be solved by the invention]

[0006] According to the method disclosed in Patent Document 1, by setting an objective function such as maximizing rigidity, minimizing displacement or stress, or minimizing strain energy, it is possible to obtain the optimal shape of a part of an automobile body that satisfies the objective function.

[0007] Therefore, the inventor of the present application attempted to obtain an optimal shape of an automobile part that receives a compressive load in the longitudinal direction so as to improve the collision performance of the automobile part by using the method of Patent Document 1. However, the obtained optimal shape of the automobile part did not necessarily improve the collision performance. The reason for this was that while an optimization analysis process in which maximization of stiffness or minimization of stress, etc., was set as an objective function, was appropriate as an index for determining stiffness, stiffness did not necessarily correlate with collision performance. Therefore, in particular, the method described in Patent Document 1 had a problem in that it was not possible to obtain an optimal shape for improving the collision performance of an automobile part that receives a compressive load in the longitudinal direction, and it was not possible to design the automobile part.

[0008] The present invention has been made to solve the above-mentioned problems, and has an object to provide a method, apparatus, and program for designing automobile parts that can design automobile parts so as to improve the collision performance of automobile parts that are subjected to compressive loads in the longitudinal direction during a vehicle collision. Furthermore, the present invention has an object to provide a method for manufacturing an automobile part that can improve the collision performance of an automobile part that receives a compressive load in the longitudinal direction during an automobile collision. [Means for solving the problem]

[0009] (1) A method for designing an automobile part according to the present invention is for designing an automobile part that receives a compressive load in a longitudinal direction during an automobile collision so as to improve the collision performance of the automobile part, the method comprising the steps of: The computer executes the following steps: An automobile part model acquisition step of acquiring an automobile part model obtained by modeling the automobile part; a design space setting step of setting a design space for a design target portion to be designed in the acquired automobile part model; a design object part model generating step of generating a design object part model for performing optimization analysis processing in the set design space; an optimization analysis condition setting step of setting optimization analysis conditions including a load condition for inputting a compressive load in a longitudinal direction of the automobile part model, an objective function for maximizing a buckling load in a primary buckling mode obtained by a linear buckling analysis, and predetermined constraint conditions related to the design target portion model; an optimization analysis step of performing an optimization analysis to obtain an optimal shape of the design object portion model generated in the automobile part model under the optimization analysis conditions; and a design object portion shape determining step of determining a shape of the design object portion on the basis of an optimum shape of the design object portion model.

[0010] (2) In the above (1), In the optimization analysis condition setting step, the objective function is set to maximize the smallest eigenvalue among eigenvalues ​​that are a solution of a characteristic equation shown in the following equation (1).

number

[0011] (3) In the above (1) or (2), The automobile part is provided with a reinforcing member attached thereto to reinforce the automobile part so as to improve the collision performance, In the design space setting step, a two-dimensional space along a surface of the automobile part model is set as a design space; In the design target portion model generating step, the design space is modeled using shell elements to generate the design target portion model, and the design target portion model is coupled to the automobile part model; The design target portion shape determining step is characterized in that a shape and a position of the reinforcing member to be attached to the automobile part are determined based on an optimal shape of the design target portion model in the automobile part model.

[0012] (4) In the above (1) or (2), In the design space setting step, the design space is set by using the automobile part model itself as the design target portion.

[0013] (5) In any one of (1) to (4) above, In the optimization analysis step, a topology optimization is performed as the optimization analysis to obtain an optimal shape of the design target portion model.

[0014] (6) In any one of (1) to (4) above, The optimization analysis step is characterized in that a plate thickness optimization is performed as an optimization analysis of the design target portion model, and the plate thickness distribution of the design target portion model obtained by the plate thickness optimization is obtained as an optimal shape of the design target portion model.

[0015] (7) In any one of (1) to (6) above, In the optimization analysis condition setting step, the load conditions are set based on a load to be input in the longitudinal direction of the automobile part, which is determined in advance by a crash analysis in which all or a part of the automobile including the automobile part is the analysis target.

[0016] (8) An automobile part design device according to the present invention is for designing an automobile part that receives a compressive load in a longitudinal direction during an automobile collision so as to improve the collision performance of the automobile part, an automobile part model acquisition unit that acquires an automobile part model obtained by modeling the automobile part; a design space setting unit that sets a design space for a design target portion that is a design target in the acquired automobile part model; a design object portion model generation unit that generates a design object portion model for performing optimization analysis processing in the set design space; an optimization analysis condition setting unit that sets optimization analysis conditions including a load condition for inputting a load in a longitudinal direction of the automobile part model, an objective function for maximizing a buckling load of a primary buckling mode obtained by a linear buckling analysis of the automobile part model, and predetermined constraint conditions for the design target portion model; an optimization analysis unit that performs optimization analysis on the automobile part model from which the design object portion model has been generated under the optimization analysis conditions, and determines an optimal shape of the design object portion model; and a design subject portion shape determination section that determines a shape of the design subject portion on the basis of an optimum shape of the design subject portion model.

[0017] (9) A design program for an automobile part according to the present invention is for designing an automobile part that receives a compressive load in a longitudinal direction during an automobile collision so as to improve the collision performance of the automobile part, Computer, an automobile part model acquisition unit that acquires an automobile part model obtained by modeling the automobile part; a design space setting unit that sets a design space for a design target portion that is a design target in the acquired automobile part model; a design object portion model generation unit that generates a design object portion model for performing optimization analysis processing in the set design space; an optimization analysis condition setting unit that sets optimization analysis conditions including a load condition for inputting a load in a longitudinal direction of the automobile part model, an objective function for maximizing a buckling load of a primary buckling mode obtained by a linear buckling analysis of the automobile part model, and predetermined constraint conditions for the design target portion model; an optimization analysis unit that executes an optimization analysis to find an optimal shape of the design object portion model under the optimization analysis conditions; The present invention is characterized in that it has a function of executing a design object portion shape determination unit that determines the shape of the design object portion on the basis of the optimum shape of the design object portion model.

[0018] (10) A method for manufacturing an automobile part according to the present invention is for manufacturing an automobile part so as to improve the collision performance of the automobile part which receives a compressive load in a longitudinal direction during an automobile collision, the method comprising the steps of: According to the shape of the reinforcing member determined by the design method of the automotive part described in (3) above, a plate-shaped reinforcing member is manufactured by press molding; The automobile part is manufactured by attaching the produced plate-shaped reinforcing member to the determined position of the reinforcing member on the automobile part.

[0019] (11) A method for manufacturing an automobile part according to the present invention is for manufacturing an automobile part so as to improve the collision performance of the automobile part which receives a compressive load in a longitudinal direction during an automobile collision, the method comprising the steps of: The automobile part is manufactured based on the shape of the automobile part determined by the automobile part design method described in (4) above. Effect of the Invention

[0020] In the present invention, in an optimization analysis of an automobile part that receives a compressive load in the longitudinal direction during an automobile collision, an objective function is set that maximizes the buckling load of the primary buckling mode, thereby enabling the design of an automobile part that has excellent crash performance in the deformation mode of axial crush, whose performance is determined by the buckling load. Furthermore, according to the present invention, it is possible to manufacture automobile parts that have excellent crash performance against the deformation mode of axial crush. [Brief description of the drawings]

[0021] [Figure 1] 1 is a block diagram showing a configuration of a design device for an automobile part according to a first embodiment of the present invention. [Diagram 2] 1 is a diagram illustrating an example of an automobile part that receives a compressive load in the longitudinal direction during an automobile collision, which is a target of the present invention. [Diagram 3]FIG. 1 is a diagram showing a rectangular cylindrical automobile part model that simulates an automobile part that receives a compressive load in the longitudinal direction during an automobile collision, and that was used as an example of a subject of study in the process of arriving at the present invention. [Figure 4] 13 is a graph showing an example of a load-stroke curve when a load is input in the longitudinal direction of a rectangular cylindrical automobile part model. [Diagram 5] FIG. 1 shows a rectangular cylindrical automobile part model used to compare the relationship between rigidity and load capacity in the process of arriving at the present invention ((a) automobile part model with bend ridges remaining, (b) automobile part model with flat surfaces remaining). [Figure 6] FIG. 1 is a graph plotting the load-stroke curves when a compressive load is input in the longitudinal direction to a rectangular cylindrical automobile part model with a bend ridge remaining and a rectangular cylindrical automobile part model with a flat surface remaining, in the process of arriving at the present invention, and the buckling loads obtained by linear buckling analysis. [Figure 7] FIG. 2 is a flow chart illustrating a process flow in the design method for an automobile part according to the first embodiment of the present invention. [Figure 8] FIG. 1 shows an optimal shape of the model of the designed portion obtained by topology optimization in Example 1, in which a two-dimensional space along the surface of the automobile part model is set as the design space to generate the model of the designed portion ((a) Example 1, (b) Comparative Example 1). [Figure 9] In Example 1, a design space is set in a two-dimensional space along the surface of the automobile part model, and a model of the design target portion is generated by topology optimization. The optimal shape of the model of the design target portion is then attached to the automobile part model ((a) Example 1, (b) Comparative Example 1). [Figure 10] 10A and 10B are diagrams showing an optimal shape of a design object part model obtained by topology optimization in Example 2, with the automobile part model itself being the design object part ((a) Example 2 of the invention, (b) Comparative Example 2). [Figure 11]11A and 11B are graphs showing load-stroke curves of optimal shapes of automobile part models obtained by topology optimization with the automobile part model itself as the design target part in Example 2 ((a) Example 2 of the invention, (b) Comparative Example 2). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Before explaining the design method, device, and program for an automobile part according to the first embodiment of the present invention, and the manufacturing method for an automobile part according to the second embodiment, the automobile part that is the subject of the present invention and the background to the invention will be described.

[0023] <Automobile parts> The automobile parts targeted by the present invention are assumed to be subjected to a compressive load in the longitudinal direction during an automobile collision. 2, examples of such automobile parts include a front side member 101, a front pillar upper 103, and a roof rail 105 in a frontal collision. Other examples include a roof center cross 107 in a side collision, and a side sill 109 in a small lap collision. These automobile parts may be composed of one part or may be composed of multiple parts (for example, the side sill 109 is composed of a side sill outer and a side sill inner). Furthermore, the present invention is not limited to automobile parts composed of one part or multiple parts, but also covers the design of automobile parts that are reinforced by attaching a reinforcing member to improve collision performance.

[0024] As described below, the present invention seeks, through optimization analysis, the optimal shapes that can improve the collision performance of these automobile parts against a compressive load input in the longitudinal direction. For this purpose, the automobile parts are assumed to be modeled using shell elements and / or solid elements, and the element information, material properties, etc. of the modeled automobile part model are assumed to be stored in an automobile part model file 31 (FIG. 1) described below.

[0025] <Background to the invention> In order to obtain the optimal shape of an automobile part by optimization analysis with the aim of improving the collision performance of the automobile part, it is necessary to appropriately set the objective function in the optimization analysis. As mentioned above, in conventional optimization analysis, the optimal shape of the automobile part is obtained by setting the objective functions of maximizing rigidity, minimizing displacement and stress, and minimizing strain energy. Also, an automobile part with high collision performance is an automobile part that has high resistance to the load input in the direction expected during a car collision, i.e., has high load resistance.

[0026] 3 shows, as an example, an automobile part model 111 that models an automobile part that receives a compressive load in the longitudinal direction. The automobile part model 111 is formed in a rectangular tube shape with a flat portion 113 and a bent ridge portion 115, and has flat plates 117 and 119 at both ends in the longitudinal direction, respectively.

[0027] The relationship between the strength and stiffness when the automobile part model 111 is subjected to a compressive load in the longitudinal direction is expressed using a load-stroke curve exemplified in FIG. 4 below. The load-stroke curve shown in FIG. 4 is a graph showing the relationship between the longitudinal displacement (stroke) of flat plate 117 attached to one end of automobile part model 111 when a compressive load is applied to flat plate 117 and the load input to automobile part model 111. In FIG. 4, the slope of the load-stroke curve in the elastic deformation region where the load and stroke are expressed in a linear relationship is the rigidity of the automobile part model 111, and the maximum load in the plastic deformation region beyond the elastic deformation region on the load-stroke curve is the strength (load capacity) of the automobile part model 111.

[0028] As shown in Figure 4, in order to accurately calculate the load capacity of an automobile part model in the plastic deformation region beyond the elastic deformation region using finite element method (FEM) analysis, etc., it is necessary to perform a time increment calculation to obtain the time change in the relationship between the load and the stroke (the displacement of the load input point in the automobile part model). However, this type of time increment calculation requires a much longer calculation time than a linear calculation (static analysis) to obtain the stiffness of the automobile part model.

[0029] Furthermore, optimization analysis, which determines the optimal shape for an automobile part model that satisfies a specified performance (objective function), requires repeated calculations. Therefore, if the objective function in optimization analysis is to maximize the load capacity of an automobile part model, the load capacity must be determined by performing time increment calculations at each step of the repeated calculations. However, performing such repeated calculations in optimization analysis is not realistic in terms of calculation time.

[0030] Therefore, in conventional optimization analyses (for example, the above-mentioned Patent Document 1), even when the objective was to improve the crashworthiness of an automobile part, the maximization of rigidity was set as the objective function from the viewpoint of calculation time. This type of optimization analysis was effective in obtaining the optimal shape of an automobile part model in which the load capacity increases according to the rigidity.

[0031] However, it has been found that, for example, in automobile part model 111A shown in FIG. 5(a) and automobile part model 111B shown in FIG. 5(b), the rigidity and the load capacity when subjected to a compressive load in the longitudinal direction do not correspond to each other.

[0032] Automobile part model 111A has a shape obtained by removing flat surface portion 113 from automobile part model 111 of rectangular tube shape shown in Fig. 3 and leaving bent ridgeline portion 115. On the other hand, automobile part model 111B has a shape obtained by removing bent ridgeline portion 115 from automobile part model 111 of rectangular tube shape shown in Fig. 3 and leaving flat surface portion 113.

[0033] FIG. 6 shows a graph comparing the relationship between the load and stroke (load-stroke curve) when a compressive load is applied in the longitudinal direction for automobile part model 111A and automobile part model 111B.

[0034] Automobile part model 111A with bent ridgeline 115 remaining has a smaller slope (rigidity) of the elastic region in the load-stroke curve (solid line in FIG. 6) but a larger maximum load than automobile part model 111B with flat portion 113 remaining. In contrast, automobile part model 111B with flat portion 113 remaining has a larger slope (rigidity) of the elastic deformation region in the load-stroke curve (solid line in FIG. 6) but a smaller maximum load than automobile part model 111A with bent ridgeline 115 remaining.

[0035] Therefore, when an optimization analysis was performed on automobile part model 111 (FIG. 3) with maximization of rigidity as the objective function, a shape with high rigidity was obtained, like automobile part model 111B, but a shape with high load-bearing capacity like automobile part model 111A could not be obtained.

[0036] The inventors have therefore conducted extensive research into such problems, and in the course of their research, have focused on the load (=buckling load) at which an automobile part that undergoes axial crushing when subjected to a compressive load in the longitudinal direction buckles.

[0037] The crashworthiness of an automobile part can be evaluated based on the maximum load (load capacity) input to the automobile part. However, at the point where the load reaches its maximum value, in many cases the automobile part is in a deformation mode due to buckling. In particular, in the case of automobile parts with complex shapes, when the compressive load applied in the longitudinal direction is gradually increased, the deformation mode changes due to buckling in the early stages of deformation, and buckling occurs continuously, progressing the deformation of the automobile part. Furthermore, when the compressive load applied to the automobile part reaches its maximum (maximum load), it is common for the deformation mode to be even larger.

[0038] As such, it is difficult to predict a state in which a large deformation mode has occurred using linear calculations (static analysis) to determine the stiffness of automotive parts. In contrast, in automotive parts where a compressive load is applied in the longitudinal direction, the limit load (= buckling load) at which the deformation mode changes from axial compression mode to another deformation mode such as bending mode can be obtained by linear buckling analysis.

[0039] Linear buckling analysis is a static analysis that determines the balance between load and displacement before buckling occurs under certain load conditions. Specifically, the buckling load is calculated as follows: If we consider the case where a load increment is given to an automobile part in a balanced state obtained by static analysis, the stiffness equation for the load increment shown in the following equation (2) can be obtained from the principle of virtual work.

[0040]

number

[0041] When an automotive part buckles under a load condition that is λ times the load under balanced stress, {ΔF} can be set to 0, so equation (3) can be obtained from the relationship in equation (2).

number

[0042] Equation (3) is a generalized eigenvalue problem, and by solving this by numerical analysis, the eigenvalue {λ} and the corresponding eigenmode {Δδ} can be obtained.

[0043] The smallest eigenvalue λ among the eigenvalues ​​{λ} is the load multiplier that gives the load at which buckling occurs relative to the load in a balanced stress state, so {K G The initial buckling load is calculated by multiplying the input load under the load conditions when} is calculated by the smallest eigenvalue λ.

[0044] In this way, linear buckling analysis is an analytical method in which the equilibrium equation at the time of buckling is derived from the principle of virtual work and treated as a generalized eigenvalue problem, and there is no need to perform time increment calculations to determine the change in load and stroke over time.

[0045] FIG. 6 mentioned above shows the results of plotting the buckling loads obtained by linear buckling analysis on a load-stroke curve for each of the automobile part model 111A (FIG. 5(a)) and the automobile part model 111B (FIG. 5(b)). As shown in FIG. 6, the buckling load obtained by linear buckling analysis shows no correlation with the rigidity in either automobile part model 111A or automobile part model 111B, but shows a correlation with the maximum load.

[0046] Based on the above considerations, the inventors came up with the idea of ​​performing an optimization analysis to obtain an optimal shape of an automobile part in a deformation mode in which the automobile part is subjected to a compressive load in the longitudinal direction and is subjected to an axial crush, with the objective function being the maximization of the buckling load obtained by a linear buckling analysis. Then, by performing such an optimization analysis, the inventors gained the knowledge that it is possible to design an automobile part so as to improve the collision performance of the automobile part subjected to a compressive load in the longitudinal direction, without requiring a large amount of calculation time. The present invention has been made based on such findings, and its specific configuration is as described below.

[0047] [Embodiment 1] <Automotive parts design equipment> An automobile part design device (hereinafter referred to as "automobile part design device") according to a first embodiment of the present invention designs automobile parts so as to improve the collision performance of the automobile parts that receive a compressive load in the longitudinal direction during an automobile collision. As shown in FIG. 1 as an example, the automobile part design device 1 is configured by a PC or the like, and includes a display device 3, an input device 5, a storage device 7, a working data memory 9, and a calculation processing unit 11. The display device 3, the input device 5, the storage device 7, and the working data memory 9 are connected to the calculation processing unit 11, and each function is executed in response to a command from the calculation processing unit 11. Each component of the automotive part design device 1 will be described below.

[0048] The display device 3 is used to display the analysis results and is configured with a liquid crystal monitor or the like. The input device 5 is used for issuing display instructions for the automobile part model file 31 and inputting conditions by the operator, and is composed of a keyboard, a mouse, and the like. The storage device 7 is used for storing various files such as the automobile part model file 31, and is configured with a hard disk or the like. The working data memory 9 is used for temporary storage of data used by the arithmetic processing unit 11 and for calculations, and is composed of a RAM (Random Access Memory) or the like.

[0049] 1, the calculation processing unit 11 includes an automobile part model acquisition unit 13, a design space setting unit 15, a design target portion model generation unit 17, an optimization analysis condition setting unit 19, an optimization analysis unit 21, and a design target portion shape determination unit 23. The calculation processing unit 11 is configured by a CPU (Central Processing Unit) such as a PC, and each of the above units functions when the CPU executes a predetermined program. In the first embodiment, an automobile part to which a reinforcing member is attached so as to improve collision performance is taken as the design object, and each unit of the automobile part design device 1 will be described.

[0050] <Automotive Parts Model Acquisition Department> The automobile part model acquisition unit 13 acquires an automobile part model that models an automobile part (see FIG. 2) that receives a compressive load in the longitudinal direction during an automobile collision.

[0051] In the design device for an automobile part according to the first embodiment, it is assumed that a reinforcing member is attached to the automobile part to reinforce the automobile part so as to improve the collision performance of the automobile part. Then, the automobile part model acquisition unit 13 acquires an automobile part model in which the automobile part is modeled using shell elements and / or solid elements.

[0052] ≪Design space setting department≫ The design space setting unit 15 sets a design space for a design target portion that is to be a design target in the automobile part model acquired by the automobile part model acquisition unit 13 . In the first embodiment, the design space setting unit 15 sets a two-dimensional space along the surface of the automobile part model as the design space.

[0053] <Design target part model generation section> The design object portion model generating unit 17 generates a design object portion model for performing optimization analysis processing in the design space set by the design space setting unit 15 . In the first embodiment, a design space set in a two-dimensional space along the surface of an automobile part model is divided into elements using shell elements, thereby generating a model of a portion to be designed.

[0054] The design target portion model generating unit 17 connects the generated design target portion model to the automobile part model. The design target portion model and the automobile part model may be connected, for example, by connecting the nodes of the design target portion model and the nodes of the automobile part model with elements (rigid elements, elastic elements, or elasto-plastic elements) (rigid connection or elastic connection). Alternatively, the nodes of the design target portion model and the automobile part model may be connected by sharing the nodes of the design target portion model and the automobile part model. Furthermore, the design target portion model generating unit 17 sets the material properties, plate thickness, etc. of the generated design target portion model according to the material of the reinforcing member that reinforces the automobile part, and, if the reinforcing member is plate-shaped, the plate thickness, etc.

[0055] <Optimization analysis condition setting section> The optimization analysis condition setting unit 19 sets load conditions, objective functions, and predetermined constraint conditions as optimization analysis conditions for the automobile part model from which the design target portion model has been generated.

[0056] The load condition is a condition for inputting a compressive load in the longitudinal direction of the automobile part model from which the design target portion model has been generated. In the present embodiment 1, the load condition is set such that a predetermined load is input along the longitudinal direction of automobile part model 111 to flat plate 117 provided at the longitudinal end of automobile part model 111 (see FIG. 3).

[0057] The load conditions include the magnitude and direction of the load to be input, the load input point, etc. The load conditions are as follows: It is preferable to set the load based on a compressive load input in the longitudinal direction of the automobile part, which is obtained in advance by a crash analysis that analyzes all or a part of the automobile including the automobile part that receives the compressive load in the longitudinal direction.

[0058] Furthermore, the optimization analysis condition setting unit 19 may set a constraint condition for constraining the displacement of the automobile part model in addition to the load condition. For example, as in the case of a rectangular cylindrical automobile part model 111 shown in Fig. 3, a condition for constraining the displacement of a flat plate 119 provided at the tip on the opposite side to a flat plate 117 which is a load input point where a load is input may be set.

[0059] The objective function is to maximize the buckling load of the primary buckling mode obtained by linear buckling analysis. In the first embodiment, the objective function is to maximize the minimum eigenvalue λ, which is the solution of the characteristic equation expressed by the above-mentioned equation (3).

[0060] The constraint condition imposes a predetermined constraint on the design object portion model in the optimization analysis, and for example, a volume constraint rate (ratio to the volume of the entire design space) of the design object portion model may be set.

[0061] <Optimization Analysis Section> The optimization analysis unit 21 performs optimization analysis on the automobile part model from which the design object portion model has been generated, under the optimization analysis conditions set by the optimization analysis condition setting unit 19, to find the optimal shape of the design object portion model.

[0062] For example, topology optimization can be applied to the optimization analysis by the optimization analysis unit 21. When a density method is used in topology optimization and there are many intermediate densities, it is preferable to discretize the topology by giving a penalty coefficient as an optimization parameter. The value of the penalty coefficient can be set appropriately.

[0063] In this embodiment 1, the optimum shape of the design object portion model is found by retaining and eliminating shell elements that constitute the design object portion model so as to satisfy the optimization analysis conditions set by optimization analysis condition setting unit 19.

[0064] The optimization analysis by the optimization analysis unit 21 can also be performed by, for example, commercially available analysis software using the finite element method.

[0065] <Design target part shape determination section> The design subject portion shape determination section 23 determines the shape of the design subject portion based on the optimal shape of the design subject portion model obtained by the optimization analysis section 21.

[0066] In this embodiment 1, the remaining shape obtained by retaining and eliminating shell elements through a topology optimization analysis process for a design target portion model modeled with shell elements is determined as the shape of a plate-like reinforcing member to be attached to an automobile part model.

[0067] Since the plate-shaped reinforcing member is preferably manufactured by, for example, press molding, the design target portion shape determination unit 23 may convert the shape determined for the plate-shaped reinforcing member into a shape that can be manufactured by press molding. For example, taking into consideration the blank workability of the plate-shaped reinforcing member, it may smooth out the irregularities in the contour of the shape determined for the plate-shaped reinforcing member. Furthermore, if the shapes remaining from the optimization analysis process are scattered over a certain range, it may be replaced with the shape of one plate-shaped reinforcing member that has the same weight and center of gravity.

[0068] Furthermore, in the first embodiment, the design target portion shape determining unit 23 determines the position at which to attach a plate-shaped reinforcing member to the automobile part, based on the determined or converted shape of the reinforcing member to be attached to the automobile part.

[0069] <Automotive part design method> The design method of an automobile part according to the first embodiment of the present invention is for designing an automobile part so as to improve the collision performance of the automobile part that receives a compressive load in the longitudinal direction during an automobile collision. The design method of an automobile part according to this embodiment includes an automobile part model acquisition step S1, a design space setting step S3, and a design target portion model generation step S5, as shown in Fig. 7. Furthermore, the design method of an automobile part according to this embodiment includes an optimization analysis condition setting step S7, an optimization analysis step S9, and a design target portion shape determination step S11, as shown in Fig. 7. Each of these steps is executed by a computer in the design method for an automobile part according to the present embodiment 1. Hereinafter, in the present embodiment 1, the design target is an automobile part to which a reinforcing member is attached so as to improve the collision performance, and each of the above steps will be described.

[0070] <Steps to obtain an automobile part model> The automobile part model acquisition step S1 is a step for acquiring an automobile part model that models an automobile part (see FIG. 2) that receives a compressive load in the longitudinal direction during an automobile collision. In the present embodiment 1, the automobile part model acquisition step S1 is executed by the automobile part model acquisition unit 13 of the automobile part design device 1. Then, in the automobile part model acquisition step S1, an automobile part model in which the automobile part is modeled using shell elements and / or solid elements is acquired.

[0071] <Design space setting step> The design space setting step S3 is a step of setting a design space for a design target portion that is to be a design target in the automobile part model acquired in the automobile part model acquisition step S1. In the present embodiment 1, the design space setting step S3 is executed by the design space setting unit 15 of the automobile part design device 1. In the design space setting step S3, a two-dimensional space along the surface of the automobile part model is set as the design space.

[0072] <Design target part model generation step> The design object portion model generating step S5 is a step for generating a design object portion model for performing an optimization analysis process in the design space set in the design space setting step S3. In the first embodiment, design target part model generating step S5 is executed by design target part model generating unit 17 of automotive part design device 1. In design target part model generating step S5, a design space set in a two-dimensional space along the surface of the automotive part model is divided into elements using shell elements to generate a design target part model.

[0073] Furthermore, in the design target portion model generation step S5, the generated design target portion model is coupled to the automobile part model. The coupling between the design target portion model and the automobile part model may be performed, for example, by coupling the nodes of the design target portion model and the nodes of the automobile part model with elements (rigid elements, elastic elements, or elasto-plastic elements) (rigid coupling or elastic coupling). Alternatively, the coupling may be performed by sharing the nodes of the design target portion model and the nodes of the automobile part model.

[0074] In addition, in the design target portion model generation step S5, the material properties and plate thickness of the generated design target portion model are set according to the material of the reinforcing member that reinforces the automobile part, and, if the reinforcing member is plate-shaped, the plate thickness, etc.

[0075] <Optimization analysis condition setting step> The optimization analysis condition setting step S7 is a step for setting optimization analysis conditions including a load condition for inputting a compressive load in the longitudinal direction of the automobile part model, an objective function for maximizing the buckling load of the primary buckling mode obtained by linear buckling analysis, and predetermined constraint conditions for the model of the part to be designed. In the present embodiment 1, the optimization analysis condition setting step S7 is executed by the optimization analysis condition setting unit 19 of the automotive part design device 1. In the optimization analysis condition setting step S7, the load conditions, the objective function, and the constraint conditions are set in the same manner as in the optimization analysis condition setting unit 19 of the automotive part design device 1.

[0076] In addition, it is preferable to set the load conditions based on a load to be input in the longitudinal direction of the automobile part model, which is obtained in advance by a crash analysis in which all or a part of an automobile including an automobile part model subjected to a compressive load in the longitudinal direction is analyzed.

[0077] In the optimization analysis condition setting step S7, similarly to the optimization analysis condition setting unit 19 of the automobile part design device 1 described above, it is preferable to set constraint conditions for constraining the displacement of the automobile part model in addition to the load conditions.

[0078] <Optimization analysis step> The optimization analysis step S9 is a step of performing optimization analysis to find an optimal shape of the design object portion model generated in the automobile part model under the optimization analysis conditions set in the optimization analysis condition setting step S7. In the first embodiment, the optimization analysis step S9 is executed by the optimization analysis unit 21 of the automotive part design device 1.

[0079] For example, topology optimization can be applied to the optimization analysis in the optimization analysis step S9. When using a density method in topology optimization and there are many intermediate densities, it is preferable to discretize the topology by giving a penalty coefficient as an optimization parameter. The value of the penalty coefficient can be set appropriately.

[0080] In the first embodiment, the optimum shape of the design object portion model is found by retaining and eliminating shell elements that constitute the design object portion model so as to satisfy the optimization analysis conditions set in optimization analysis condition setting step S7.

[0081] The optimization analysis in the optimization analysis step S9 can be performed, for example, by using commercially available analysis software using the finite element method.

[0082] <Step to determine the shape of the part to be designed> The design subject portion shape determination step S11 determines the shape of the design subject portion based on the optimal shape of the design subject portion model obtained in the optimization analysis step S9. In the first embodiment, the design target portion shape determining step S11 is executed by the design target portion shape determining unit 23 of the automobile component design device 1.

[0083] In this embodiment 1, the remaining shape obtained by retaining and eliminating shell elements through a topology optimization analysis process for a design target portion model modeled with shell elements is determined as the shape of a plate-like reinforcing member to be attached to an automobile part model.

[0084] Since a plate-shaped reinforcing member is preferably manufactured by, for example, press molding, in design target portion shape determination step S11, the shape determined for the plate-shaped reinforcing member may be converted into a shape that can be manufactured by press molding. For example, in consideration of blanking processability of the plate-shaped reinforcing member, it is advisable to smooth out the unevenness of the contour of the determined shape of the plate-shaped reinforcing member. Furthermore, when the shapes remaining after the optimization analysis process are scattered in a certain range area, it is advisable to replace the shapes of the plate-shaped reinforcing member with the shape of one plate-shaped reinforcing member having the same weight and center of gravity.

[0085] Furthermore, in the first embodiment, in the design target portion shape determination step S21, the position at which the plate-shaped reinforcing member is to be attached to the automobile part is determined based on the determined or converted shape of the reinforcing member to be attached to the automobile part.

[0086] <Automotive parts design program> The above description of the first embodiment has been about the design device and method for an automobile part. However, the first embodiment can be configured as a design program for an automobile part that causes each unit in the arithmetic processing unit 11 of the automobile part design device 1 (FIG. 1) configured by a computer to function.

[0087] The design program for the automobile part according to the first embodiment is for designing the automobile part so as to improve the collision performance of the automobile part that receives a compressive load in the longitudinal direction during an automobile collision. The design program for an automotive part according to the first embodiment has the function of causing a computer to operate as an automotive part model acquisition unit 13, a design space setting unit 15, a design target portion model generation unit 17, an optimization analysis condition setting unit 19, an optimization analysis unit 21, and a design target portion shape determination unit 23, like the calculation processing unit 11 shown in FIG. 1.

[0088] As described above, in the design device, method, and program for an automobile part according to the first embodiment, an optimization analysis is performed to obtain an optimal shape of a reinforcing member that reinforces an automobile part that receives a compressive load in the longitudinal direction during an automobile collision so as to improve the collision performance. In the optimization analysis, an objective function that maximizes the buckling load in the primary buckling mode is set. This makes it possible to design an automobile part reinforced with a reinforcing member so as to improve the collision performance in the deformation mode of axial crush, in which the buckling load determines the performance.

[0089] In addition, the above-mentioned embodiment 1 is directed to designing an automobile part by determining the optimal shape and position of a reinforcing member to be attached to reinforce the automobile part in order to improve the collision performance against a compressive load input in the longitudinal direction during an automobile collision.

[0090] However, as another aspect of the first embodiment, the shape of the automobile part itself may be determined and the automobile part may be designed so as to improve the collision performance of the automobile part that receives a compressive load in the longitudinal direction.

[0091] For example, in a method for designing an automobile part according to another aspect of the first embodiment, the shape of the automobile part may be determined by the following procedure.

[0092] First, in a design space setting step, a design space is set with the automobile part model itself as the design target portion.

[0093] Next, in the design object portion model generating step, a design object portion model is generated using shell elements and / or solid elements. At this time, the design object portion model may be generated using the shell elements and / or solid elements used in modeling the automobile part model.

[0094] Then, the material properties and plate thickness of the generated model of the part to be designed are set according to the material of the automotive part to be designed, and, if the automotive part is manufactured by press-molding a metal plate as described below, the plate thickness, etc.

[0095] Next, in the optimization analysis condition setting step, optimization analysis conditions are set for the automobile part model from which the design target portion model has been generated, with the objective function being maximization of the buckling load in the primary buckling mode. In the optimization analysis condition setting step, the load conditions, constraint conditions, and restriction conditions may be set in the same manner as in the first embodiment described above.

[0096] Next, an optimization analysis is performed on the design object portion model under the set optimization analysis conditions to find an optimal shape of the design object portion model.

[0097] Then, the shape of the automobile part, which is the design target portion, is determined based on the optimal shape of the model of the design target portion.

[0098] When topology optimization is applied in optimization analysis, the three-dimensional position data of the remaining shape (element density distribution above a certain threshold) of the design target part is input into a CAD / CAM program. Next, the shape of the car part can be determined by carrying out CAD processing such as smoothing and shape optimization processing in accordance with the constraints of the actual manufacturing of the car part.

[0099] Similarly, the design device and program for an automobile part according to another aspect of this embodiment 1 may be designed to improve the collision performance of the automobile part by determining the optimal shape of the automobile part itself that is subjected to a compressive load in the longitudinal direction. In this way, in other aspects of this embodiment 1, automobile parts that are subjected to compressive loads in the longitudinal direction can be designed to improve the collision performance in the axial crush deformation mode, in which the buckling load determines the collision performance.

[0100] In the above description, topology optimization is performed as the optimization analysis for determining the optimal shape of the design target portion model generated in the automobile part model, but the present invention may also perform thickness optimization for determining the optimal thickness distribution of the design target portion model as the optimization analysis. In this case, the shape of the design target portion in the automobile part model can be determined as follows.

[0101] When a two-dimensional space along the surface of an automobile part model is set as a design space, the shape of the design target part model remaining after removing parts with a thickness less than a predetermined thickness from the optimal thickness distribution obtained by thickness optimization is obtained as the optimal shape of a reinforcing member to be affixed to the automobile part. In this case, the predetermined thickness used as the basis for removal may be appropriately set in consideration of the collision performance and weight.

[0102] In addition, when the design space is set with the automobile part model itself as the design target part, the part where the plate thickness obtained by the plate thickness optimization analysis is greater than the plate thickness of the original automobile part model is determined as the part where a reinforcing member is to be affixed, and the shape of that part is determined as the shape of the reinforcing member. Alternatively, the shape of the part to be designed may be determined by deleting parts whose plate thickness is equal to or smaller than a predetermined value compared to the plate thickness of the automobile part model.

[0103] In addition, the automobile part model is not limited to a model of only the automobile part that is the subject of design, but may also include other automobile parts that are installed in the surrounding area but are not the subject of design.

[0104] [Embodiment 2] The method of designing an automobile part according to the first embodiment described above is for designing an automobile part so as to improve the collision performance of the automobile part that receives a compressive load in the longitudinal direction during an automobile collision.

[0105] However, the present invention can be configured to manufacture automobile parts by improving the collision performance of the automobile parts that receive a compressive load in the longitudinal direction during an automobile collision.

[0106] In the manufacturing method of an automobile part according to the second embodiment, first, the design method of an automobile part according to the first embodiment described above is used to determine the shape and position of a reinforcing member to be attached to the automobile part so as to improve collision performance. Next, a plate-shaped reinforcing member is produced by press molding according to the determined shape of the reinforcing member.

[0107] Furthermore, the manufactured plate-shaped reinforcing member is attached to the determined position of the reinforcing member for the automobile part, thereby manufacturing the automobile part. Specific examples of methods for attaching a plate-shaped reinforcing member to an automobile part include welding such as resistance spot welding, arc welding, and laser welding, adhesion using a structural adhesive, or a weld bond method that combines spot welding and adhesion.

[0108] To attach a plate-shaped reinforcing member to an automobile part, first, the position data of the three-dimensional coordinates of the automobile part is obtained, and then the obtained position data of the three-dimensional coordinates of the automobile part is converted into assembly data. The assembly data is data (NC data) in a format used by assembly robots in the manufacturing process of automobile bodies, and the converted assembly data is read into an NC unit. The NC unit that has read the converted assembly data is then used to assemble the automobile parts by attaching plate-shaped reinforcing members to them.

[0109] In this way, according to the manufacturing method of the automobile part of the second embodiment, it is possible to manufacture an automobile part reinforced with a reinforcing member so as to improve the collision performance in the axial crush deformation mode when subjected to a compressive load in the longitudinal direction during a vehicle collision.

[0110] Furthermore, as a manufacturing method for an automobile part according to another aspect of the present embodiment 2, an automobile part may be manufactured based on the shape of the automobile part determined by the design method for an automobile part according to another aspect of the present embodiment 1 described above.

[0111] When the shape of an automobile part is determined using a design method for an automobile part according to another aspect of embodiment 1, the automobile part can be manufactured by press-molding a metal plate, as described below as an example.

[0112] First, CAD data of the automobile part is acquired based on the shape of the automobile part determined by the method for designing an automobile part according to another aspect of the first embodiment.

[0113] Next, CAD data for a press-molding die is created based on the acquired CAD data for the automobile part, and the press-molding die is created based on the created CAD data for the press-molding die.The automobile part is then manufactured using the created press-molding die.

[0114] Specific examples of how to prepare a press molding die include the following. The CAD data for press molding dies is input into a CAD / CAM program linked to an NC machine tool and converted into NC data (NC program) for NC processing. The NC machine tool machines the die model for full mold casting or the steel die. Then, using the acquired NC data (NC program), the NC machine tool produces the die model for casting or the steel die, and the actual press molding die is created.

[0115] According to another aspect of the manufacturing method of an automobile part according to the second embodiment described above, it is possible to manufacture an automobile part whose shape is determined so as to enhance collision performance against deformation modes such as axial crushing when subjected to a compressive load in the longitudinal direction. EXAMPLES

[0116] Using the method, device, and program for designing an automobile part according to the present invention, an analysis was performed to verify the effect of improving the collision performance of an automobile part subjected to a compressive load in the longitudinal direction, and this will be described below.

[0117] <Example 1: Optimal shape of reinforcing member for automobile parts> In the first embodiment, a rectangular cylindrical automobile part model 111 modeled with shell elements as shown in FIG. 3 was used as an analysis target, and an optimal shape of a reinforcing member for reinforcing the automobile part model 111 was obtained.

[0118] Automobile part model 111 simulates an automobile part that receives a compressive load in the longitudinal direction during an automobile collision, and is formed in a square tube shape with four flat surfaces 113 and a bent ridge portion 115 connecting adjacent flat surfaces 113. Flat plates 117 and 119 are provided at both ends in the longitudinal direction of automobile part model 111. Automobile part model 111 is a square tube with one side measuring 50 mm and a height of 100 mm, and is made of a steel plate with a plate thickness of 1 mm and a tensile strength of 1,180 MPa.

[0119] In Example 1, which is an example of the invention, an optimization analysis was performed to obtain an optimal shape of a reinforcing member that improves the crash performance of an automobile part against a compressive load input in the longitudinal direction.

[0120] In the optimization analysis, first, an automobile part model 111 modeled with shell elements was obtained, and a two-dimensional space along the surfaces of a flat portion 113 and a bend ridge portion 115 in the automobile part model 111 was set as a design space. Then, a design target portion model was generated for the set design space using shell elements. Furthermore, the nodes of the design target portion model and the nodes of the automobile part model were linked by sharing them.

[0121] Next, for the automobile part model 111, load conditions, constraint conditions, objective functions, and constraint conditions were set as optimization analysis conditions. The loading condition was a condition in which a load of 1 kN was input in the longitudinal direction to flat plate 117 on one end side in the longitudinal direction, and the restraining condition was a condition in which flat plate 119 on the other end side was restrained. The objective function was set to maximize the eigenvalue of the primary buckling mode of the automobile part model, and the constraint was set to ensure that the volume of the model of the part to be designed was 30% or less of the volume of the design space.

[0122] Then, an optimization analysis using topology optimization was performed under the set optimization analysis conditions, and the remaining design target portion model was obtained as the optimal shape of the reinforcing member.

[0123] In addition, in Example 1, as Comparative Example 1, only the objective function among the optimization analysis conditions set in Invention Example 1 was changed to “minimization of the displacement of the flat plate 117”, and optimization analysis was performed using topology optimization to obtain the optimal shape of the model of the part to be designed.

[0124] FIG. 8 shows the optimum shapes of the reinforcing members obtained by optimization analysis in Example 1 and Comparative Example 1. As shown in FIG. 8(a), the optimum shape 121 of the reinforcing member in Example 1 of the invention was a shape that remained along the longitudinal direction of the bent ridge portion 115, with almost no shape remaining on the flat portion 113 of the automobile part model 111. In contrast, as shown in FIG. 8(b), the optimum shape 123 of the reinforcing member in Comparative Example 1 was such that almost no part remained on the bent ridge line portion 115, and a roughly H-shape remained on the flat portion 113.

[0125] The optimal shape 121 of the reinforcing member according to Example 1 and the optimal shape 123 of the reinforcing member according to Comparative Example 2 were attached to an automobile part model 111, and an axial compression analysis was performed in which a compressive load was input to a flat plate 117 at one end in the longitudinal direction. The load-stroke curve was obtained, and the result is shown in FIG. 9.

[0126] As shown in FIG. 9, in Example 1 of the invention and Comparative Example 1, a reinforcing member of optimal shape 121 or 123 was attached to the original automobile part model 111, so there was no significant difference in the rigidity (slope of the load-stroke curve in the elastic region) between the two.

[0127] However, the maximum load was higher in Example 1 of the invention, in which maximization of the buckling load was the objective function, than in Comparative Example 1, and even in the strokes after the maximum load, the load of Example 1 of the invention was higher than that of Comparative Example 1.

[0128] This result indicates that the automobile part model 111 to which the reinforcing member of the optimum shape 121 according to the invention example 1 is attached has superior collision performance in the deformation mode of axial crush.

[0129] <Example 2: Optimal shape of automotive parts> In the second embodiment, a rectangular cylindrical automobile part model 111 modeled with shell elements as shown in FIG. 3 was used as a design target portion, and an optimal shape thereof was obtained.

[0130] As in the first embodiment described above, the automobile part model 111 is formed in a rectangular tube shape with four flat surfaces 113 and a bent ridge portion 115 connecting adjacent flat surfaces 113. A flat plate 117 and a flat plate 119 are provided at both ends in the longitudinal direction of the automobile part model 111. The automobile part model 111 is a rectangular tube with a side of 50 mm and a height of 100 mm, and is made of a steel plate with a thickness of 1 mm and a tensile strength of 1,180 MPa.

[0131] In Example 2, as an example of the invention 2, an optimization analysis was performed to obtain an optimal shape for improving the crash performance of an automobile part model 111 that receives a compressive load in the longitudinal direction.

[0132] In the optimization analysis, first, an automobile part model 111 modeled with shell elements was obtained, and a flat portion 113 and a bend ridgeline portion 115 in the automobile part model 111 were set as a design space. Then, for the set design space, a design target portion model was generated using the shell elements of the flat portion 113 and the bend ridgeline portion 115.

[0133] Next, as optimization analysis conditions, the load conditions, the constraint conditions, the objective function, and the constraint conditions were set for the automobile part model 111, similarly to the first embodiment. However, in the second embodiment, the constraint condition was set such that the volume of the design object portion model was 50% or less of the volume of the design space.

[0134] Then, an optimization analysis using topology optimization was performed under the set optimization analysis conditions, and the optimal shape of the remaining design target portion model was obtained.

[0135] In addition, in the embodiment, as Comparative Example 2, only the objective function among the optimization analysis conditions set in Invention Example 2 was changed to “minimization of the displacement of the flat plate 117”, and optimization analysis was performed using topology optimization to obtain the optimal shape of the model of the part to be designed.

[0136] FIG. 10 shows the optimum shape of the automobile part model 111 obtained by optimization analysis in the second invention example and the second comparative example. As shown in FIG. 10(a), the optimum shape 131 of the automobile part model in the invention example 2 is a shape in which the flat portion 113 has almost disappeared and remains at the portion corresponding to the bent ridge portion 115 (FIG. 3). In contrast, the optimum shape 133 of the automobile part model in Comparative Example 2 is a shape in which the bend ridgeline portion 115 has almost disappeared and remains in the portion corresponding to the flat portion 113 (FIG. 3), as shown in FIG. 10(b).

[0137] For each of the optimum shape 131 of the invention example 2 and the optimum shape 133 of the comparative example 2, an axial compression analysis was performed by inputting a load to the flat plate 117 at one end in the longitudinal direction, and the load-stroke curve was obtained, and the results are shown in FIG. 11. 11, the stiffness (slope of the load-stroke curve in the elastic region) was higher in Comparative Example 2, which aimed to maximize stiffness. However, the maximum load was higher in Example 2, which aimed to maximize the buckling load as an objective function, and the maximum load in Comparative Example 2 was significantly lower than that of Example 2.

[0138] This result indicates that the automobile part having the shape according to Example 2 of the present invention is superior in collision performance in the deformation mode of axial crush. [Explanation of symbols]

[0139] 1 Automotive parts design equipment 3 Display device 5 Input Devices 7 Storage device 9 Working Data Memory 11 Processing unit 13 Automotive Parts Model Acquisition Department 15 Design space setting section 17 Design target part model generation unit 19 Optimization analysis condition setting section 21 Optimization Analysis Section 23 Design target part shape determination section 31 Auto Parts Model File 100 Automobile bodies 101 Front side member 103 Front pillar upper 105 roof rail 107 Roof center cross 109 Side sill 111 Auto Parts Model 111A Auto Parts Model 111B Auto Parts Model 113 Plane section 115 Bending ridge 117 Flat plate 119 Flat plate 121 Optimal shape (reinforcement member, invention example 1) 123 Optimum shape (reinforcement member, comparative example 1) 131 Optimal Shape (Automobile Parts, Invention Example 2) 133 Optimum Shape (Automobile Parts, Comparative Example 2)

Claims

1. A method for designing an automobile part that is subjected to a compressive load in a longitudinal direction during an automobile collision so as to improve the collision performance of the automobile part, comprising: The computer executes the following steps: An automobile part model acquisition step of acquiring an automobile part model obtained by modeling the automobile part; a design space setting step of setting a design space for a design target portion to be designed in the acquired automobile part model; a design object part model generating step of generating a design object part model for performing optimization analysis processing in the set design space; an optimization analysis condition setting step of setting optimization analysis conditions including a load condition for inputting a compressive load in a longitudinal direction of the automobile part model, an objective function for maximizing a buckling load in a primary buckling mode obtained by a linear buckling analysis, and predetermined constraint conditions related to the design target portion model; an optimization analysis step of performing an optimization analysis to obtain an optimal shape of the design object portion model generated in the automobile part model under the optimization analysis conditions; and a design object portion shape determining step of determining a shape of the design object portion based on an optimum shape of the design object portion model.

2. 2. The method for designing an automotive part according to claim 1, wherein in the optimization analysis condition setting step, the objective function is set to maximize a minimum eigenvalue among eigenvalues ​​that are solutions to a characteristic equation shown in the following equation (1). [0010]

3. The automobile part is provided with a reinforcing member attached thereto to reinforce the automobile part so as to improve the collision performance, In the design space setting step, a two-dimensional space along a surface of the automobile part model is set as a design space; In the design target portion model generating step, the design space is modeled using shell elements to generate the design target portion model, and the design target portion model is coupled to the automobile part model; 3. The method for designing an automobile part according to claim 1, wherein in the design target portion shape determination step, a shape and a position of the reinforcing member to be attached to the automobile part are determined based on an optimal shape of the design target portion model in the automobile part model.

4. 3. The method for designing an automobile part according to claim 1, wherein in the design space setting step, the design space is set by using the automobile part model itself as the design target portion.

5. 3. The method for designing an automobile part according to claim 1, wherein in the optimization analysis step, a topology optimization is performed as the optimization analysis to obtain an optimal shape of the model of the design target portion.

6. 3. The method for designing an automotive component according to claim 1 or 2, characterized in that, in the optimization analysis step, a plate thickness optimization is performed as an optimization analysis of the design target portion model, and a plate thickness distribution of the design target portion model obtained by the plate thickness optimization is obtained as an optimal shape of the design target portion model.

7. 3. The design method for an automobile part according to claim 1 or 2, characterized in that, in the optimization analysis condition setting step, the load conditions are set based on a load to be input in the longitudinal direction of the automobile part, which is obtained in advance by a crash analysis in which all or a part of the automobile including the automobile part is the analysis target.

8. An automobile part design device that designs an automobile part that receives a compressive load in a longitudinal direction during an automobile collision so as to improve the collision performance of the automobile part, an automobile part model acquisition unit that acquires an automobile part model obtained by modeling the automobile part; a design space setting unit that sets a design space for a design target portion that is a design target in the acquired automobile part model; a design object portion model generation unit that generates a design object portion model for performing optimization analysis processing in the set design space; an optimization analysis condition setting unit that sets optimization analysis conditions including a load condition for inputting a load in a longitudinal direction of the automobile part model, an objective function for maximizing a buckling load of a primary buckling mode obtained by a linear buckling analysis of the automobile part model, and predetermined constraint conditions for the design target portion model; an optimization analysis unit that performs optimization analysis on the automobile part model from which the design object portion model has been generated under the optimization analysis conditions, and determines an optimal shape of the design object portion model; a design object portion shape determination unit that determines a shape of the design object portion based on an optimal shape of the design object portion model.

9. A design program for an automobile part that designs an automobile part that receives a compressive load in a longitudinal direction during an automobile collision so as to improve the collision performance of the automobile part, Computer, an automobile part model acquisition unit that acquires an automobile part model obtained by modeling the automobile part; a design space setting unit that sets a design space for a design target portion that is a design target in the acquired automobile part model; a design object portion model generation unit that generates a design object portion model for performing optimization analysis processing in the set design space; an optimization analysis condition setting unit that sets optimization analysis conditions including a load condition for inputting a load in a longitudinal direction of the automobile part model, an objective function for maximizing a buckling load of a primary buckling mode obtained by a linear buckling analysis of the automobile part model, and predetermined constraint conditions for the design target portion model; an optimization analysis unit that executes an optimization analysis to find an optimal shape of the design object portion model under the optimization analysis conditions; a design target portion shape determination unit that determines a shape of the design target portion based on an optimal shape of the design target portion model.

10. A method for manufacturing an automobile part that is subjected to a compressive load in a longitudinal direction during an automobile collision so as to improve the collision performance of the automobile part, comprising: A plate-shaped reinforcing member is manufactured by press molding according to the shape of the reinforcing member determined by the method for designing an automobile part according to claim 3; A method for manufacturing an automobile part, comprising the steps of: manufacturing the automobile part by attaching the manufactured plate-shaped reinforcing member to the determined position of the reinforcing member on the automobile part.

11. A method for manufacturing an automobile part that is subjected to a compressive load in a longitudinal direction during an automobile collision so as to improve the collision performance of the automobile part, comprising:

5. A method for manufacturing an automobile part, comprising the steps of: manufacturing the automobile part based on a shape of the automobile part determined by the method for designing an automobile part according to claim 4.

Images