Automobile body design method, automobile body design apparatus, automobile body design program, and automobile body manufacturing method.

Abstract

We design and manufacture automobile bodies that improve vehicle performance by integrating multiple body parts into a single component. [Solution] The automobile body design method according to the present invention involves setting a target range for body parts to be integrated in the automobile body 100 (S1a), setting a design space 131 in a joint 123 where multiple body parts are joined within the target range (S1b), setting a coupling element 133 in the set design space 131 for integrating the joined multiple body parts (S1c), setting boundary conditions for external forces and constraints to evaluate the body performance (S3a), setting an objective function for the body performance and constraint conditions for the coupling element 133 as optimization analysis conditions (S3b), performing an optimization analysis to find the optimal coupling element 141 under the boundary conditions and optimization analysis conditions (S3c), and determining multiple body parts to be integrated into one part based on the optimal coupling element 141 (S3d).

Description

Technical Field

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[0001] The present invention relates to an automobile body design method, an automobile body design device, an automobile body design program for designing an automobile body with improved body performance, and a method for manufacturing an automobile body.

Background Art

[0002] In the design of automobile bodies, optimization analysis techniques using computers are used for the purpose of improving body performance. For example, Patent Document 1 discloses an optimization analysis technique for obtaining an optimal shape of a vehicle body structure that improves the rigidity and collision characteristics of the vehicle body or realizes weight reduction while maintaining the rigidity and collision performance at a predetermined value. Further, Patent Document 2 discloses an optimization analysis technique for obtaining the optimal positions of point joints or continuous joints between components of a body structure model of a vehicle body composed of a plurality of components.

Prior Art Documents

Patent Documents

[0005] However, even if multiple body parts that were previously joined together by spot welding or other means are integrated into a single component, it is not guaranteed that the vehicle's performance will necessarily improve depending on which body parts are integrated. Therefore, it is important to use computer-based optimization analysis technology to determine which body parts are best suited for integration from the perspective of improving vehicle performance.

[0006] The optimization analysis technique described in Patent Document 1 was a method for determining the optimal shape of the vehicle body structure in order to improve the desired performance. Therefore, it was not possible to obtain results that would allow for the determination of the optimal vehicle body part to be integrated among multiple vehicle body parts, and thus it was unsuitable for the challenge of reducing manufacturing costs. Furthermore, the optimization analysis technique described in Patent Document 2 was a method for determining the optimal position for spot welding and continuous welding to join body parts together without changing the shape of the body parts that constitute the body structure. Therefore, although a certain reduction in manufacturing costs can be expected by performing optimization calculations aimed at reducing the number of welding points, it did not contribute to eliminating the process of processing body parts by press forming.

[0007] The present invention was made to solve the above-mentioned problems, and aims to provide an automobile body design method, an automobile body design apparatus, and an automobile body design program that can design an automobile body with improved automobile body performance by integrating multiple automobile body parts as a single component. Furthermore, the present invention aims to provide a method for manufacturing an automobile body that improves the performance of an automobile body by integrating multiple body parts as a single component. [Means for solving the problem]

[0008] (1) The automobile body design method according to the present invention involves a computer performing the following steps in order to design an automobile body that improves the performance of the automobile body by integrating multiple automobile body parts into a single part: An optimization analysis model generation step for generating an optimization analysis model for performing an optimization analysis on the multiple vehicle body parts that are best suited to be integrated into a single part, The process includes an optimization analysis step of performing the optimization analysis using the generated optimization analysis model, The aforementioned optimization analysis model generation step is: A step of setting the scope of the body parts to be integrated, which is to set the scope of the body parts to be integrated with all or part of the existing automobile body, A design space setting step in which a design space to be targeted for the optimization analysis is set at the joint where the plurality of vehicle body parts are joined within the set target range, The process includes setting a coupling element in order to set coupling elements that connect multiple vehicle body parts that are joined together in the set design space to integrate them into a single part, The aforementioned optimization analysis step is: A boundary condition setting step in which boundary conditions relating to external forces and constraints are set for the optimization analysis model in order to evaluate the vehicle body performance in the aforementioned optimization analysis model, An optimization analysis condition setting step, which sets the objective function relating to the vehicle body performance and the constraint conditions relating to the coupling elements set in the optimization analysis model as optimization analysis conditions, An optimization analysis step is performed to determine the optimal coupling element in the optimization analysis model under the boundary conditions and the optimization analysis conditions, The present invention is characterized by comprising: a process for determining an integrated vehicle body part, which determines a plurality of vehicle body parts to be integrated into a single part based on the optimal coupling element obtained by the optimization analysis;

[0009] (2) In the items described in (1) above, In the aforementioned coupling element setting step, the coupling element is characterized in that a shell element having an elastic modulus equal to or greater than that of a steel plate is used, and the nodes of the shell element and the nodes of the elements that model the plurality of vehicle body parts are shared.

[0010] (3) In the items described in (1) above, The aforementioned coupling element setting step is characterized in that a solid element having an elastic modulus equal to or greater than that of a steel plate is used as the coupling element, and the solid element and the elements that model the plurality of vehicle body parts are connected by rigid elements.

[0011] (4) In any of the items described in (1) to (3) above, The aforementioned vehicle body performance is defined as bending rigidity or torsional rigidity. The boundary condition setting step is characterized by setting an external force that causes bending or twisting in the optimization analysis model, and constraints on the translation and / or rotation of the optimization analysis model or constraints on the optimization analysis model by an inertia relief method, as the boundary conditions.

[0012] (5) In any of the items described in (1) to (3) above, The aforementioned vehicle body performance is defined as collision performance. The boundary condition setting step is characterized by setting an external force corresponding to the collision load during a vehicle collision, and constraints on the translation and / or rotation of the optimization analysis model or constraints on the optimization analysis model by the inertia relief method, as the boundary conditions.

[0013] (6) In any of the items described in (1) to (3) above, The aforementioned vehicle body performance is defined as vibration characteristics, In the boundary condition setting step, as the boundary conditions, an external force for inputting vibrations in a specific frequency band to a predetermined position in the optimization analysis model and constraints on the translation and / or rotation of the optimization analysis model or constraints on the optimization analysis model by the inertia relief method are set. This is the gist of the invention.

[0014] (7) In the case of the above (4), In the optimization analysis condition setting step, as the objective function, minimization of the compliance of the entire optimization analysis model or minimization of the displacement at a predetermined position in the optimization analysis model is set. This is the gist of the invention.

[0015] (8) In the case of the above (5), In the optimization analysis condition setting step, as the objective function, minimization of the compliance of the entire optimization analysis model or minimization of the displacement at a predetermined position in the optimization analysis model is set. This is the gist of the invention.

[0016] (9) In the case of the above (6), In the optimization analysis condition setting step, as the objective function, minimization of the inertance at a predetermined position in the optimization analysis model or minimization of the equivalent radiation power of a predetermined part in the optimization analysis model is set. This is the gist of the invention.

[0017] (10) The automobile body design device according to the present invention designs an automobile body in which the body performance is improved by integrating a plurality of body parts in an existing automobile body as one part. An optimization analysis model generation unit that generates an optimization analysis model for performing optimization analysis on the plurality of body parts that are optimal for integration into one part, An optimization analysis unit that performs the optimization analysis using the generated optimization analysis model, are provided. The optimization analysis model generation unit A unit for setting the target range of the body parts that integrate all or part of the existing automobile body, A design space setting unit sets the design space to be targeted for the optimization analysis at the joint where the multiple vehicle body parts are joined within the set target range, The system includes a coupling element setting unit which sets coupling elements for joining multiple vehicle body parts that are joined together in the set design space to integrate them as a single part, The aforementioned optimization analysis unit is The aforementioned optimization analysis model includes a boundary condition setting unit that sets boundary conditions relating to external forces and constraints applied to the optimization analysis model in order to evaluate the vehicle body performance, An optimization analysis condition setting unit sets the objective function relating to the vehicle body performance and the constraint conditions relating to the coupling elements set in the optimization analysis model as optimization analysis conditions, An optimization analysis unit performs an optimization analysis to determine the optimal coupling element in the optimization analysis model under the boundary conditions and the optimization analysis conditions, The present invention is characterized by having an integrated vehicle body part determination unit that determines a plurality of vehicle body parts to be integrated into a single part based on the optimal coupling element obtained by the optimization analysis described above.

[0018] (11) The automobile body design program according to the present invention designs an automobile body that improves the performance of the automobile body by integrating multiple automobile body parts in an existing automobile body into a single part, Computers, An optimization analysis model generation unit that generates an optimization analysis model for performing an optimization analysis on the multiple vehicle body parts that are best suited to be integrated into a single part, An optimization analysis unit that performs the optimization analysis using the generated optimization analysis model, and a function that is executed as such, moreover, The aforementioned optimization analysis model generation unit, A unit for setting the target range of the body parts that integrate all or part of the existing automobile body, A design space setting unit sets the design space to be targeted for the optimization analysis at the joints that join adjacent vehicle body parts within the set target range, A coupling element setting unit is provided to set coupling elements in order to integrate multiple vehicle body parts that are joined together into a single part within the set design space, and to function as such. The aforementioned optimization analysis unit, The aforementioned optimization analysis model includes a boundary condition setting unit that sets boundary conditions relating to external forces and constraints applied to the optimization analysis model in order to evaluate the vehicle body performance, An optimization analysis condition setting unit sets the objective function relating to the vehicle body performance and the constraint conditions relating to the coupling elements set in the optimization analysis model as optimization analysis conditions, An optimization analysis unit performs an optimization analysis to determine the optimal coupling element in the optimization analysis model under the boundary conditions and the optimization analysis conditions, The present invention is characterized by functioning as an integrated vehicle body part determination unit that determines multiple vehicle body parts to be integrated into a single part based on the optimal coupling element obtained by the aforementioned optimization analysis.

[0019] (12) The method for manufacturing an automobile body according to the present invention manufactures an automobile body with improved body performance by integrating multiple body parts of an existing automobile body into a single part, Using the automobile body design method described in any of (1) to (3) above, determine the number of body parts to be integrated into a single part. The method is characterized by manufacturing the multiple vehicle body parts that have been determined as a single integrated part. [Effects of the Invention]

[0020] In this invention, by determining multiple body parts that can be integrated into a single component in an existing automobile body to improve body performance, it is possible to design an automobile body that improves body performance and reduces the manufacturing cost of the automobile body. Furthermore, according to the present invention, by manufacturing multiple vehicle body parts that can improve vehicle body performance by integrating them into a single part, it is possible to manufacture a vehicle body that improves vehicle body performance and reduces the manufacturing cost of the vehicle body. [Brief explanation of the drawing]

[0021] [Figure 1] This is a block diagram showing the configuration of an automobile body design device according to Embodiment 1 of the present invention. [Figure 2] This figure shows the automobile body designed in Embodiment 1 of the present invention, the scope of integration, and the body parts. [Figure 3] This figure shows the design space set at the joint of a plurality of vehicle body parts to be integrated, and the connecting element of a solid element that integrates and connects the plurality of vehicle body parts, in Embodiment 1 of the present invention. [Figure 4] This figure shows a rear member in which a connecting element is set at the joint of a plurality of vehicle body parts to be integrated, according to Embodiment 1 of the present invention. [Figure 5] This figure illustrates another aspect of Embodiment 1 of the present invention, showing a design space set at the joint of a plurality of vehicle body parts to be integrated, and a connecting element of a shell element that integrates and connects the plurality of vehicle body parts. [Figure 6] This figure shows the boundary conditions set in the optimization analysis model as optimization analysis conditions in Embodiment 1 of the present invention. [Figure 7] This figure shows the optimal coupling element obtained by optimization analysis in Embodiment 1 of the present invention. [Figure 8] This figure shows the vehicle body parts that were determined to be integrated into a single component based on the optimal coupling elements obtained by optimization analysis in Embodiment 1 and the examples of the present invention. [Figure 9] This is a flowchart showing the processing flow of the automobile body design method according to Embodiment 1 of the present invention. [Figure 10] In the example, this figure illustrates the vehicle body part to be integrated as Comparative Example 2 ((a) coupling elements remaining after optimization analysis, (b) vehicle body part to be integrated). [Modes for carrying out the invention]

[0022] Before describing Embodiments 1 and 2 of the present invention, the automobile body targeted by the present invention will be described. In the drawings of this application, the X-axis direction, Y-axis direction, and Z-axis direction refer to the longitudinal direction of the vehicle body, the width direction of the vehicle body, and the vertical direction of the vehicle body, respectively.

[0023] <Automobile body> As an example, the automobile body 100 is composed of multiple body parts, as shown in Figure 2(a). Examples of multiple body parts include the rear side member front 111, rear side member barrier 113, rear side member front inner gusset 115, rear cross member 117-1, 117-2, and rear cross member gusset 119-1, 119-2, as shown in Figure 2(b). These are body frame components that constitute the rear member 110 of the automobile body 100.

[0024] The automobile body 100 is composed of body parts modeled with shell elements and / or solid elements. The element information and material properties of each body part modeled with shell elements and / or solid elements are stored in the automobile body model file 7a (Figure 1), which will be described later.

[0025] [Embodiment 1] <Automotive Body Design Equipment> The automobile body design apparatus according to Embodiment 1 of the present invention designs an automobile body 100 in which the performance of the automobile body is improved by integrating multiple automobile body parts of an existing automobile body 100 as a single part. As an example, the automobile body design apparatus 1 is composed of a PC (personal computer) or the like, as shown in Figure 1, and includes a display device 3, an input device 5, a storage device 7, a working data memory 9, and an arithmetic processing unit 11. Furthermore, in the automobile body design apparatus 1, the display device 3, the input device 5, the storage device 7, and the working data memory 9 are connected to the arithmetic processing unit 11, and their respective functions are executed by commands from the arithmetic processing unit 11. The following describes the various components of the automobile body design device 1.

[0026] The display device 3 is used for displaying analysis results, etc., and consists of a liquid crystal monitor or the like. The input device 5 is used for displaying the automobile body model file 7a and for inputting operator conditions, and consists of a keyboard, mouse, etc. The storage device 7 is used for storing various files such as automobile body model files 7a, and is composed of a hard disk or the like. The working data memory 9 is used for temporary storage and calculation of data used by the arithmetic processing unit 11, and is composed of RAM (Random Access Memory), etc.

[0027] As shown in Figure 1, the arithmetic processing unit 11 comprises an optimization analysis model generation unit 13 and an optimization analysis unit 15, and is configured by a CPU (Central Processing Unit) of a PC or the like. Each of these units functions when the CPU executes a predetermined program. The functions of each of the above-mentioned units in the arithmetic processing unit 11 are described below.

[0028] ≪Optimization Analysis Model Generation Unit≫ The optimization analysis model generation unit 13 generates an optimization analysis model that performs an optimization analysis on the optimal body parts for integrating multiple body parts. As shown in Figure 1, the optimization analysis model generation unit 13 includes an integrated body part target range setting unit 13a, a design space setting unit 13b, and a coupling element setting unit 13c.

[0029] (Setting the range of target for integrated vehicle body parts) As shown in Figure 2, the integrated body part target range setting unit 13a sets the rear member 110, which is part of the existing automobile body 100, as the target range for the body parts to be integrated.

[0030] (Design space setting department) As shown in Figure 3, the design space setting unit 13b sets the design space 131 to be targeted for optimization analysis at the joint 123 where multiple body parts 121A and 121B are joined together in the rear member 110, which is the target range set by the integrated body part target range setting unit 13a.

[0031] (Combination element setting section) As shown in Figure 3, the coupling element setting unit 13c sets coupling elements 133 in the design space 131 set by the design space setting unit 13b in order to integrate multiple joined vehicle body parts 121A and 121B into a single part.

[0032] As the connecting element 133, a solid element having an elastic modulus equal to or greater than that of the steel plate, which is the material of the vehicle body part, can be used. When a solid element is used for the connecting element 133, as shown in Figure 3, the vehicle body parts 121A and 121B are joined by connecting the nodes of the connecting element 133 to the nodes of the vehicle body parts 121A and 121B with rigid elements 135.

[0033] In Figure 3, the spot welding points that join body part 121A and body part 121B are omitted, but the joining element setting section 13c joins body part 121A and body part 121B by the joining element 133 while maintaining the spot welding points.

[0034] Figure 4 shows the rear member 110 in an optimization analysis model in which connecting elements 133 are set using solid elements at the joints 123 of multiple body parts such as the rear side member front 111 and the rear side member barrier 113. The connecting elements 133 shown in Figure 4 are set by arranging solid elements to fill the gaps between body parts at each joint 123, and are connected to the body parts using rigid elements (not shown in Figure 4).

[0035] Furthermore, the connecting element is not limited to a solid element; a shell element having an elastic modulus equal to or greater than that of the steel plate, which is the material of the vehicle body part, can also be used. In this case, for example, as shown in Figure 5, a shell element connecting element 137 is placed in a design space 131 set at the joint 123 where vehicle body parts 121A and 121B are joined by spot welding points 125. By sharing the nodes of the connecting element 137 with the nodes of vehicle body parts 121A and 121B, vehicle body parts 121A and 121B can be joined while maintaining the spot welding points 125.

[0036] Optimization Analysis Unit The optimization analysis unit 15 performs optimization analysis using the optimization analysis model generated by the optimization analysis model generation unit 13. As shown in Figure 1, the optimization analysis unit 15 includes a boundary condition setting unit 15a, an optimization analysis condition setting unit 15b, an optimization analysis unit 15c, and an integrated vehicle body part determination unit 15d.

[0037] (Boundary condition setting section) The boundary condition setting unit 15a sets boundary conditions related to external forces and constraints applied to the optimization analysis model in order to evaluate vehicle performance in the optimization analysis.

[0038] In this embodiment 1, the vehicle body performance related to torsional stiffness is evaluated in the optimization analysis. Therefore, as shown in Figure 6, the boundary condition setting unit 15a sets boundary conditions for evaluating torsional stiffness in the optimization analysis model 140 in which the coupling elements have been set by the coupling element setting unit 13c. The boundary conditions shown in Figure 6 assume that the external forces input to the optimization analysis model 140 are applied to the left and right suspension tower tops (A in Figure 6) at the front of the vehicle, with loads (+1000N, -1000N) in opposite directions in the vertical direction of the vehicle body. Furthermore, the boundary conditions shown in Figure 6 constrain the optimization analysis model 140 to the vertical translation of the vehicle body at the midpoint of the left and right suspension tower tops A (B in Figure 6), and to the longitudinal and widthwise translation of the vehicle body at the rear subframe mounting position (C in Figure 6).

[0039] (Optimization analysis condition setting unit) The optimization analysis condition setting unit 15b sets the objective function related to vehicle body performance and the constraint conditions related to the coupling element 133 set in the optimization analysis model 140 as optimization analysis conditions.

[0040] As described above, in this embodiment 1, the vehicle body performance related to torsional rigidity is evaluated in the optimization analysis. Therefore, the optimization analysis condition setting unit 15b sets the objective function to minimize the compliance of the entire optimization analysis model 140 when a torsional load is applied. Furthermore, it sets a constraint that the volume ratio of the connecting elements 133 set at the joints 123 of multiple vehicle body parts in the optimization analysis model 140 is 10% or less. Here, the volume ratio of the connecting elements 133 is the ratio of the volume of the connecting elements 133 to the volume of the design space 131 set in the optimization analysis model 140.

[0041] (Optimization Analysis Department) The optimization analysis unit 15c performs an optimization analysis to find the optimal coupling element in the optimization analysis model 140, under the boundary conditions set by the boundary condition setting unit 15a and the optimization analysis conditions set by the optimization analysis condition setting unit 15b.

[0042] In this embodiment 1, topology optimization is applied to the optimization analysis performed by the optimization analysis unit 15c. In topology optimization using the density method, the virtual material density of the coupling element is used as a design variable, and the optimal coupling element is determined by performing the optimization analysis process to determine whether the coupling element remains or is eliminated.

[0043] Figure 7 shows the optimal coupling element 141 obtained by the optimization analysis performed by the optimization analysis unit 15c. As shown in Figure 7, the result was obtained that many coupling elements 141 remain at the joint 123 between the rear side member front 111 and the rear side member barrier 113. Furthermore, the result was obtained that coupling elements 141 also remain at the joint 123 between the rear side member barrier 113 and the rear cross member gusset 119-2.

[0044] (Decision-making section for integrated vehicle body parts) The integrated body part determination unit 15d determines multiple body parts to be integrated into a single part based on the optimal coupling element 141 obtained by the optimization analysis performed by the optimization analysis unit 15c.

[0045] The multiple body parts to be integrated are defined as multiple body parts in which the optimal connecting element 141, determined by the optimization analysis performed by the optimization analysis unit 15c, is located at the joint 123. In this case, the area where the optimal connecting element 141 is located can be the area where the multiple body parts are integrated into a single part.

[0046] In this embodiment 1, as shown in Figure 8(a), many optimal connecting elements 141 remain at the joint 123 between the rear side member front 111 and the rear side member barrier 113. Therefore, as shown in Figure 8(b), the integrated body part determination unit 15d determines that the rear side member front 111 and the rear side member barrier 113 are integrated into a single body part 151. This reduces the rear member 110, which was composed of 12 body parts, to 10 body parts.

[0047] Furthermore, as shown in Figure 7, the connecting element 141 remains at the joint 123 between the rear side member barrier 113 and the rear cross member gusset 119-2. Therefore, the integrated body part determination section 15d may determine the rear side member front 111, the rear side member barrier 113, and the rear cross member gusset 119-2 as a single body part. In this case, the rear member 110, which was composed of 12 body parts, can be reduced to 8 body parts.

[0048] <Automotive Body Design Methods> The automobile body design method according to Embodiment 1 of the present invention designs an automobile body with improved performance by integrating multiple body parts of an existing automobile body into a single component. The automobile body design method according to Embodiment 1, as shown in Figure 9, includes an optimization analysis model generation step S1 and an optimization analysis step S3, and these steps are performed by a computer. In the following description, each of the above steps will be performed using the automobile body design apparatus 1 (Figure 1) according to Embodiment 1, which is configured by a computer.

[0049] ≪Optimization Analysis Model Generation Steps≫ The optimization analysis model generation step S1 generates an optimization analysis model for performing an optimization analysis on the optimal body part for integrating multiple body parts, and is performed by the optimization analysis model generation unit 13 of the automobile body design apparatus 1. As shown in Figure 9, the optimization analysis model generation step S1 includes an integrated body part target range setting step S1a, a design space setting step S1b, and a coupling element setting step S1c.

[0050] (Process for setting the scope of integrated vehicle body parts) As shown in Figure 2, the integrated body part target range setting step S1a sets the rear member 110, which is part of the existing automobile body 100, as the target range for the body parts to be integrated. In this embodiment 1, the integrated body part target range setting step S1a is performed by the integrated body part target range setting unit 13a of the automobile body design device 1.

[0051] (Design space setting process) As shown in Figure 3, the design space setting step S1b sets the design space 131 to be targeted for optimization analysis at the joint where multiple vehicle body parts are joined within the target range set in the integrated vehicle body part target range setting step S1a. In this embodiment 1, the design space setting step S1b is performed by the design space setting unit 13b of the automobile body design device 1.

[0052] (Connection element setting process) The coupling element setting step S1c involves setting coupling elements 133 in the design space 131 set in the design space setting step S1b, in order to integrate multiple joined vehicle body parts into a single part. In this embodiment 1, the coupling element setting step S1c is performed by the coupling element setting unit 13c of the automobile body design apparatus 1.

[0053] If multiple vehicle body parts are joined at joint 123 by spot welding points, the joining element setting step S1c places the joining element 133 in the design space 131 while maintaining the spot welding points, and joins the vehicle body parts together.

[0054] In the coupling element setting step S1c, the coupling element 133 can be a solid element having an elastic modulus equal to or greater than that of the steel plate, which is the material of the vehicle body part. In this case, for example, as shown in Figure 3, the coupling element 133 can be placed in the design space 131, and the vehicle body parts 121A and 121B can be joined together by connecting the nodes of the coupling element 133 to the nodes of the vehicle body parts 121A and 121B with rigid elements 135.

[0055] Alternatively, in the coupling element setting step S1c, the coupling element may be a solid element having an elastic modulus equal to or greater than that of the steel plate, which is the material of the vehicle body part. In this case, for example, as shown in Figure 5, the coupling element 137 is placed in the design space 131, and the vehicle body parts 121A and 121B can be coupled to the rigid element 135 by sharing the nodes of the coupling element 133 with the nodes of the vehicle body parts 121A and 121B.

[0056] ≪Optimization Analysis Steps≫ The optimization analysis step S3 is a step in which an optimization analysis is performed using the optimization analysis model 140 generated in the optimization analysis model generation step S1, and is executed by the optimization analysis unit 15 of the automobile body design device 1. As shown in Figure 9, the optimization analysis step S3 includes a boundary condition setting step S3a, an optimization analysis condition setting step S3b, an optimization analysis step S3c, and an integrated body part determination step S3d.

[0057] (Boundary condition setting process) The boundary condition setting step S3a is a step in which boundary conditions related to external forces and constraints applied to the optimization analysis model in order to evaluate vehicle body performance in the optimization analysis, as shown in Figure 6 above. In this embodiment 1, the boundary condition setting step S3a is performed by the boundary condition setting unit 15a of the automobile body design device 1. This sets the boundary conditions shown in Figure 6 for the optimization analysis model 140 generated by setting the coupling element 133 in the coupling element setting step S1c.

[0058] (Optimization analysis condition setting process) The optimization analysis condition setting step S3b sets the objective function related to vehicle body performance and the constraint conditions related to the coupling elements set in the optimization analysis model 140 as optimization analysis conditions. In this embodiment 1, the optimization analysis condition setting step S3b is performed by the optimization analysis condition setting unit 15b of the automobile body design device 1.

[0059] In this embodiment 1, the objective function is to minimize the overall compliance of the optimization analysis model 140 under torsional load application as shown in Figure 6, and the constraint is that the volume ratio of the connecting elements 133 set in the design space 131 of multiple vehicle body parts in the optimization analysis model 140 is 10% or less.

[0060] (Optimization analysis process) The optimization analysis step S3c performs an optimization analysis to find the optimal coupling element 141, as shown in Figure 7, under the boundary conditions set in the boundary condition setting step S3a and the optimization analysis conditions set in the optimization analysis condition setting step S3b. In this embodiment 1, the optimization analysis step S3c is performed by the optimization analysis unit 15c of the automobile body design device 1.

[0061] Topology optimization can be applied to the optimization analysis in the optimization analysis process S3c. Topology optimization using the density method uses the virtual material density of the connecting elements (shell elements or solid elements) as a design variable, and by performing the optimization analysis process, the optimal connecting elements can be determined by determining whether the connecting elements remain or are eliminated.

[0062] (Process for determining integrated vehicle body components) The integrated body part determination process S3d determines multiple body parts to be integrated into a single part based on the optimal coupling element 141 (Figure 7) obtained by the optimization analysis in the optimization analysis process S3c. In this embodiment 1, the integrated body part determination process S3d is performed by the integrated body part determination unit 15d of the automobile body design apparatus 1. Figure 8 shows the integrated body part 151 formed in the integrated body part determination process S3d, in which the rear side member front 111 and the rear side member barrier 113 are integrated into a single part.

[0063] <Automotive Body Design Program> The above description of Embodiment 1 concerned an automobile body design apparatus 1 and an automobile body design method. However, Embodiment 1 can be configured as an automobile body design program that enables the operation of each unit in the calculation processing unit 11 of the automobile body design apparatus 1 (Figure 1), which is configured by a computer.

[0064] In other words, the automobile body design program according to this embodiment 1 designs an automobile body that improves its performance by integrating multiple body parts from an existing automobile body into a single component. Furthermore, the automobile body design program according to this embodiment 1 causes the computer to function as an optimization analysis model generation unit 13 and an optimization analysis unit 15, as shown in the calculation processing unit 11 in Figure 1.

[0065] Here, the automobile body design program according to this embodiment 1 makes the computer function as an optimization analysis model generation unit 13, and thus enables the various parts of the optimization analysis model generation unit 13 to function. As shown in Figure 1 above, the optimization analysis model generation unit 13 includes an integrated body part target range setting unit 13a, a design space setting unit 13b, and a coupling element setting unit 13c.

[0066] Furthermore, the automobile body design program according to this embodiment 1 enables the computer to function as an optimization analysis unit 15, thereby enabling the various parts of the optimization analysis unit 15 to function. As shown in Figure 1 above, the optimization analysis unit 15 includes a boundary condition setting unit 15a, an optimization analysis condition setting unit 15b, an optimization analysis unit 15c, and an integrated body part determination unit 15d.

[0067] In the automobile body design method, automobile body design apparatus, and automobile body design program according to this first embodiment, multiple automobile body components are determined that can improve the performance of an existing automobile body by integrating them into a single component. This makes it possible to design an automobile body that improves performance and reduces manufacturing costs.

[0068] The above explanation assumed that the rear member 110 of the automobile body 100 shown in Figure 2 was the target range for the body parts to be integrated. However, in the present invention, the entire automobile body 100 may be set as the target range for the body parts to be integrated.

[0069] Furthermore, in generating an optimization analysis model using the integrated body part target range setting unit or in the integrated body part target range setting process, the present invention may be obtained by measuring the part shape and assembly state of all or some of the body parts using an actual existing automobile body. Here, the assembly state refers to, for example, the size and spacing of the spot welding points when multiple body parts are joined by spot welding. In addition, any method such as optical measurement or contact measurement can be used to measure the part shape and assembly state of the body parts.

[0070] If it is not possible to use an actual existing automobile body, the part shapes and assembly methods of all or some of the body parts may be obtained from the design drawing data of an existing automobile body, and an optimization analysis model may be generated. Furthermore, an optimization analysis model may be generated by combining the part shape and assembly method obtained through measurement with the part shape and assembly method obtained from design drawing data.

[0071] Furthermore, while the multiple body parts to be integrated were joined by spot welding, they could also be multiple body parts assembled by laser welding or bolts. In this case, the laser-welded areas or bolted areas should be designated as joints, and the design space should be defined accordingly.

[0072] In the above explanation, the elastic modulus of the connecting elements set at the joints of multiple vehicle body parts was set to be equal to or greater than that of the steel plate, but the density of the connecting elements should be a value that is sufficiently small compared to that of the steel plate (for example, almost zero).

[0073] In this first embodiment, the vehicle body performance to be evaluated in the optimization analysis was defined as torsional stiffness, and boundary conditions corresponding to this were set in the optimization analysis model. However, in the present invention, it is sufficient to set the external forces and constraints to be set as boundary conditions according to the vehicle body performance to be evaluated.

[0074] For example, when evaluating bending stiffness as a vehicle performance feature, external force conditions are set regarding the direction, magnitude, and position of the external force (load) applied to the optimization analysis model, as well as constraint conditions regarding the position that constrain translation and rotation in the optimization analysis model.

[0075] When evaluating collision performance as a measure of vehicle performance, it is advisable to set boundary conditions that include an external force corresponding to the collision load during a vehicle collision, and constraints on the translation and / or rotation of the optimization analysis model. Here, the external force set as the boundary conditions is the position, magnitude, and direction at which the collision load is input to the optimization analysis model, and the constraints are the position and direction that restrict the translation and / or rotation of the vehicle body during a vehicle collision.

[0076] When evaluating vibration characteristics as part of vehicle performance, it is advisable to set boundary conditions that include an external force inputting vibrations of a specific frequency band at predetermined positions in the optimization analysis model, and constraints on the translation and / or rotation of the optimization analysis model. Here, the external force set as boundary conditions is the position, magnitude, and direction of the vibration input to the optimization analysis model, and the constraints are the position and direction that constrain the translation and / or rotation of the optimization analysis model into which the vibration is input.

[0077] Furthermore, when setting boundary conditions, instead of setting constraints on the optimization analysis model as described above, constraints on the optimization analysis model may be set using the inertia relief method.

[0078] The inertia relief method is an analytical technique that determines stress and strain from the forces acting on an object undergoing uniformly accelerated motion while the object is supported at a support point that serves as the reference point for the inertial force coordinates (free support state). It is used in static analysis of aircraft and ships in motion. Therefore, to set constraints on an optimization analysis model using the inertia relief method, it is sufficient to set the optimization analysis model to a state where it is supported at the support point that serves as the reference point for the inertial force coordinates.

[0079] The objective function in optimization analysis should also be set according to the vehicle performance being evaluated. When evaluating bending stiffness or collision characteristics, as with evaluating torsional stiffness, it is advisable to set the objective function as minimizing the compliance or strain energy of the entire optimization analysis model, or minimizing the displacement at a predetermined position in the optimization analysis model.

[0080] Furthermore, when evaluating vibration characteristics, it is advisable to set the objective function as minimizing the inertance at a given location in the optimization analysis model, or minimizing the equivalent radiated power at a given part.

[0081] Inertance is a vibration characteristic expressed as the ratio of the force applied to an object to the resulting acceleration, and is also called the vibration transfer function. In an optimization analysis model, a predetermined position that minimizes inertance is, for example, the top of the center pillar. Equivalent radiated power is a simplified indicator of the sound level emitted by a vibrating structure. It represents a vibration characteristic based on the idea that the perpendicular component of the structure's vibration velocity imparts energy to the acoustic space. In an optimization analysis model, the parts that minimize equivalent radiated power are typically the roof panel or door panel.

[0082] In the above explanation, the constraint in the optimization analysis was defined as the volume fraction of the connecting elements. However, it is not limited to this; for example, constraints that represent the volume of the design space, such as the weight or number of connecting elements, may also be set.

[0083] The present invention does not limit the optimization analysis to topology optimization; it may also involve optimization analysis using other calculation methods, and for example, commercially available analysis software using the finite element method can be used for the optimization analysis.

[0084] In the present invention, when determining which body parts to integrate based on the results of the optimal bonding element analysis, it may also consider whether multiple body parts with remaining bonding elements at the joints can be press-formed as a single part. For example, if it is difficult to press-form multiple body parts that have been determined to be integrated into a single part based on the remaining bonding elements through optimization analysis, these body parts may not be integrated.

[0085] Furthermore, if there are body parts that are difficult to press-form as a single integrated component, these body parts may be excluded from the selection of body parts to be integrated. Furthermore, even if it is difficult to press-form a part as a single component, it may be decided to manufacture it as a single body part by casting or other methods instead of press forming. This makes it possible to find body parts that are effective in improving vehicle performance through integration.

[0086] [Embodiment 2] The automobile body design method according to Embodiment 1 described above was a method for designing an automobile body that improves body performance by integrating multiple body parts of an existing automobile body into a single component.

[0087] However, the present invention can be configured as a method for manufacturing an automobile body by integrating multiple existing automobile body parts into a single component to produce an automobile body.

[0088] In the automobile manufacturing method according to this second embodiment, first, multiple body parts to be integrated into a single component are determined using the automobile body design method according to the first embodiment described above. Then, the multiple body parts to be integrated are manufactured as a single component.

[0089] Thus, according to the automobile body manufacturing method of this second embodiment, it is possible to manufacture an automobile body while improving the performance of the vehicle body and reducing manufacturing costs.

[0090] In the automobile body manufacturing method according to this second embodiment, the body parts to be integrated as a single component may be manufactured, for example, by press forming using a single blank. Furthermore, if the plate thickness, strength, etc., of the multiple body parts to be integrated differ, they may be press-formed using a tailored blank. [Examples]

[0091] An analysis was conducted to verify the effects of Embodiment 1 of the present invention, and this will be described below. In this embodiment, as described in Embodiment 1, multiple body parts to be integrated into a single component in the rear member 110 of the automobile body 100 were determined, and torsional rigidity was determined as a measure of the body performance. Here, as shown in Figure 8 above, Invention Example 1 is an example in which two vehicle body parts, the rear side member front 111 and the rear side member barrier 113, are integrated into a single part based on the optimal connecting element 141.

[0092] Furthermore, as a point of comparison, a composite of the entire rear member 110 was designated as Comparative Example 1. In addition, as shown in Figure 10, a composite of seven body parts—the left and right rear side member fronts 111, the rear side member front inner gusset 115, the rear cross member gusset 119-1, and the rear cross member 117-1—was designated as Comparative Example 2. In Comparative Example 2, as shown in Figure 6, the integrated body part was such that no connecting element 141 remained at the joint 123 after optimization analysis.

[0093] Then, for each of the automobile body 100 equipped with the rear member 110 of Invention Example 1, Comparative Example 1, and Comparative Example 2, the torsional rigidity was determined by applying boundary conditions (external forces and constraints, see Figure 6) in the optimization analysis, and the improvement rate of the torsional rigidity was calculated. Torsional rigidity (kNm / rad) = (Absolute value of the load in the z direction applied to each suspension tower top (kN)) × 2 × (Distance between the left and right suspension towers (m)) / (Angle around the x-axis of the line segment connecting the left and right suspension tower tops (rad)) The percentage improvement in torsional rigidity (%) = ((torsional rigidity of the automobile body of Invention Example 1, Comparative Example 1, or Comparative Example 2) - (torsional rigidity of the original automobile body)) / (torsional rigidity of the original automobile body) × 100

[0094] The improvement in torsional rigidity in Invention Example 1 was 2.7%, which was almost the same as the improvement in torsional rigidity (=2.9%) in Comparative Example 1, in which the entire rear member 110 was integrated. In contrast, the improvement in torsional rigidity in Comparative Example 2 was 0.2%, indicating that there was virtually no improvement in torsional rigidity due to the integration of body parts.

[0095] As described above, according to the present invention, it is possible to determine multiple body parts that can improve the performance of an existing automobile body by integrating them into a single component, and to design an automobile body that can reduce manufacturing costs. [Explanation of Symbols]

[0096] 1. Automobile body design device 3 Display device 5 Input devices 7 Storage device 7a Automobile body model file 9 Working data memory 11. Arithmetic Processing Unit 13. Optimization Analysis Model Generation Unit 13a Integrated vehicle body part target range setting section 13b Design space setting section 13c Joint element setting section 15 Optimization Analysis Unit 15a Boundary condition setting section 15b Optimization analysis condition setting unit 15c Optimization Analysis Department 15d Integrated vehicle body part determination section 100 automobile body 110 Rear Member 111 Rear side member front 113 Rear side barrier 115 Rear side member front inner gusset 117-1, 117-2 Rear Cross Member 119-1, 191-2 Rear Cross Member Gusset 121 Body parts 121A Body parts 121B Body parts 123 Joint 125 Spot Welding Model Section 131 Design space 133. Joined elements (solid elements) 135 Rigid Body Elements 137. Connecting elements (shell elements) 140 Optimization Analysis Models 141 Optimal binding elements 151 Integrated vehicle body parts (Example of invention 1) 153 Integrated vehicle body parts (Comparative Example 2)

Claims

1. A car body design method in which a computer performs the following steps in order to design a car body that improves car body performance by integrating multiple car body parts of an existing car body into a single part, An optimization analysis model generation step for generating an optimization analysis model for performing an optimization analysis on the multiple vehicle body parts that are best suited to be integrated into a single part, The process includes an optimization analysis step of performing the optimization analysis using the generated optimization analysis model, The aforementioned optimization analysis model generation step is: A step of setting the scope of the body parts to be integrated, which is to set the scope of the body parts to be integrated with all or part of the existing automobile body, A design space setting step in which a design space to be targeted for the optimization analysis is set at the joint where the plurality of vehicle body parts are joined within the set target range, The process includes setting a coupling element in order to set coupling elements that connect multiple vehicle body parts that are joined together in the set design space to integrate them into a single part, The aforementioned optimization analysis step is: A boundary condition setting step in which boundary conditions relating to external forces and constraints are set for the optimization analysis model in order to evaluate the vehicle body performance in the aforementioned optimization analysis model, An optimization analysis condition setting step, which sets the objective function relating to the vehicle body performance and the constraint conditions relating to the coupling elements set in the optimization analysis model as optimization analysis conditions, An optimization analysis step is performed to determine the optimal coupling element in the optimization analysis model under the boundary conditions and the optimization analysis conditions, A method for designing an automobile body, comprising: a step of determining an integrated body part, which determines a plurality of body parts to be integrated into a single part based on the optimal coupling element obtained by the optimization analysis.

2. The automobile body design method according to claim 1, characterized in that, in the joint element setting step, a shell element having an elastic modulus equal to or greater than that of a steel plate is used as the joint element, and the nodes of the shell element and the nodes of the elements that model the plurality of automobile body parts are shared.

3. The automobile body design method according to claim 1, characterized in that, in the step of setting the connecting element, a solid element having an elastic modulus equal to or greater than that of a steel plate is used as the connecting element, and the solid element and the element that models the plurality of automobile body parts are connected by a rigid element.

4. The aforementioned vehicle body performance is defined as bending rigidity or torsional rigidity. The automobile body design method according to any one of claims 1 to 3, characterized in that, in the boundary condition setting step, an external force that causes bending or twisting in the optimization analysis model, and constraints on the translation and / or rotation of the optimization analysis model or constraints on the optimization analysis model by an inertia relief method are set as the boundary conditions.

5. The aforementioned vehicle body performance is defined as collision performance. The automobile body design method according to any one of claims 1 to 3, characterized in that, in the boundary condition setting step, an external force corresponding to the collision load during a vehicle collision and the translational and / or rotational constraints of the optimization analysis model or the constraints of the optimization analysis model by the inertia relief method are set as the boundary conditions.

6. The aforementioned vehicle body performance is defined as vibration characteristics, The automobile body design method according to any one of claims 1 to 3, characterized in that, in the boundary condition setting step, an external force that inputs vibrations of a specific frequency band to a predetermined position in the optimization analysis model, and constraints on the translation and / or rotation of the optimization analysis model or constraints on the optimization analysis model by an inertia relief method are set as the boundary conditions.

7. The automobile body design method according to claim 4, characterized in that, in the optimization analysis condition setting step, the objective function is set to minimize the compliance of the entire optimization analysis model or to minimize the displacement of a predetermined position in the optimization analysis model.

8. The automobile body design method according to claim 5, characterized in that, in the optimization analysis condition setting step, the objective function is set to minimize the compliance of the entire optimization analysis model or to minimize the displacement of a predetermined position in the optimization analysis model.

9. The automobile body design method according to claim 6, characterized in that, in the optimization analysis condition setting step, the objective function is set to minimize the inertance at a predetermined position in the optimization analysis model or to minimize the equivalent radiated power of a predetermined part in the optimization analysis model.

10. An automobile body design device for designing an automobile body that improves the performance of the automobile body by integrating multiple automobile body parts into a single part in an existing automobile body, An optimization analysis model generation unit that generates an optimization analysis model for performing an optimization analysis on the multiple vehicle body parts that are best suited to be integrated into a single part, The system comprises an optimization analysis unit that performs the optimization analysis using the generated optimization analysis model, The aforementioned optimization analysis model generation unit is: A unit for setting the range of target body parts that integrate all or part of the existing automobile body, A design space setting unit sets the design space to be targeted for the optimization analysis at the joint where the multiple vehicle body parts are joined within the set target range, The system includes a coupling element setting unit which sets coupling elements for joining multiple vehicle body parts that are joined together in the set design space to integrate them as a single part, The aforementioned optimization analysis unit is The aforementioned optimization analysis model includes a boundary condition setting unit that sets boundary conditions relating to external forces and constraints applied to the optimization analysis model in order to evaluate the vehicle body performance, An optimization analysis condition setting unit sets the objective function relating to the vehicle body performance and the constraint conditions relating to the coupling elements set in the optimization analysis model as optimization analysis conditions, An optimization analysis unit performs an optimization analysis to determine the optimal coupling element in the optimization analysis model under the boundary conditions and the optimization analysis conditions, An automobile body design apparatus characterized by having an integrated body part determination unit that determines a plurality of body parts to be integrated into a single part based on the optimal coupling element obtained by the optimization analysis.

11. An automobile body design program for designing an automobile body that improves the performance of the automobile body by integrating multiple automobile body parts into a single component, Computers, An optimization analysis model generation unit that generates an optimization analysis model for performing an optimization analysis on the multiple vehicle body parts that are best suited to be integrated into a single part, An optimization analysis unit that performs the optimization analysis using the generated optimization analysis model, and a function that is executed as such, moreover, The aforementioned optimization analysis model generation unit, A unit for setting the range of target body parts that integrate all or part of the existing automobile body, A design space setting unit sets the design space to be targeted for the optimization analysis at the joints that join adjacent vehicle body parts within the set target range, A coupling element setting unit is provided to set coupling elements in order to integrate multiple vehicle body parts that are joined together into a single part within the set design space, and to function as such. The aforementioned optimization analysis unit, The aforementioned optimization analysis model includes a boundary condition setting unit that sets boundary conditions relating to external forces and constraints applied to the optimization analysis model in order to evaluate the vehicle body performance, An optimization analysis condition setting unit sets the objective function relating to the vehicle body performance and the constraint conditions relating to the coupling elements set in the optimization analysis model as optimization analysis conditions, An optimization analysis unit performs an optimization analysis to determine the optimal coupling element in the optimization analysis model under the boundary conditions and the optimization analysis conditions, An automobile body design program characterized by functioning as an integrated body part determination unit that determines a plurality of body parts to be integrated into a single part based on the optimal coupling elements obtained by the optimization analysis.

12. A method for manufacturing an automobile body that improves the performance of an automobile body by integrating multiple body parts of an existing automobile body into a single part, Using the automobile body design method described in any one of claims 1 to 3, a plurality of body parts to be integrated into a single part are determined, A method for manufacturing an automobile body, characterized by manufacturing the determined plurality of vehicle body parts as a single integrated part.

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