Analysis device, analysis method, and computer program

Abstract

To easily select a natural vibration mode that corresponds to a difference value of strain energy, stress vector or strain vector of a member without carrying out spring-back analysis and enable analysis for reducing the deformation of the member that is considered to be caused by spring-back.SOLUTION: The present invention generates, by press molding analysis, first distribution data that indicates the distribution of at least one parameter among the strain energy, stress vector and strain vector of a member, generates second distribution data that indicates the distribution of parameters of the member in each natural vibration mode, finds the degree of coincidence between both distribution data, and selects one or a plurality of natural vibration modes on the basis of the degree of coincidence.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an analysis device, an analysis method, and a computer program. [Background technology]

[0002] Due to the demand for collision safety and weight reduction, the tensile strength of steel plates used in automobile bodies and the like exceeds 590 MPa and is approaching the GPa unit. High-strength steel plates can increase the energy absorption and strength during a collision without increasing the plate thickness. Compared to other lightweight materials, the processing and assembly of parts using high-strength steel plates does not necessarily require major changes in equipment and production technology. Therefore, the burden on production costs of processing and assembly of parts using high-strength steel plates is considered to be relatively small compared to other lightweight materials.

[0003] However, in the case of press forming, as the strength of the steel plate increases, springback and wrinkles increase, making it difficult to ensure the dimensional accuracy of the parts. In addition, the decrease in ductility that accompanies the increase in strength increases the risk of breakage during press forming. As such, achieving both performance and productivity with high-strength steel plate is not necessarily easier than with conventional mild steel plate, and combined with the need to shorten development periods and reduce manufacturing costs, the burden of developing processing technology for mass production is greatly increased.

[0004] Of the above-mentioned breakage, wrinkles, and springback, breakage and wrinkles are issues that can occur even when conventional mild steel sheets are used, depending on the part shape, forming conditions, etc., and a great deal of knowledge, countermeasures, etc. have been accumulated so far. On the other hand, springback is an issue specific to the use of high-strength steel sheets, and has not yet been fully studied. It cannot be said that widely used forming simulations have sufficient practical reliability in terms of predicting dimensional accuracy by springback analysis.

[0005] Springback is the elastic deformation that occurs in a part to achieve a new equilibrium, driven by residual stress, when the part is removed from the mold after molding, when unnecessary parts are trimmed, or when other tasks that relieve the constraints on the part are performed. Since high-strength steel sheets have a large springback, it is difficult to ensure the dimensional accuracy required for the final product.

[0006] Springback is classified into "angle change", "wall warpage", "twist", "ridge warpage" and "punch bottom springback" according to the phenomenon. In all cases, residual stress distribution in the part acts as a bending or twisting moment, and the part is deformed according to the rigidity determined by the elastic coefficient of the material, the plate thickness, the part shape, etc. For example, the most well-known examples of springback are bending angle change and wall warpage. These springbacks are driven by the stress distribution in the plate thickness direction, and the rigidity is mainly determined by the plate thickness. Alternatively, when a hat-shaped beam curved in the longitudinal direction is draw-formed, wall warpage and twist occur, but if the curvature of the curve is small, the part rigidity increases and the wall warpage decreases.

[0007] Based on this mechanism, one of the countermeasures against poor dimensional accuracy is to change the plate thickness, part shape, etc., to increase the rigidity according to the elastic deformation mode of springback, and to increase the resistance to springback.

[0008] Increasing the resistance to springback definitely reduces dimensional change. Resistance to springback is the stiffness of a part against its elastic deformation mode. To increase the stiffness of a part, the shape of the part is an important factor. Since the shape of a part is restricted by the requirements of performance, layout, etc., small measures such as beads and embossing are effective.

[0009] Beads against wall warpage are the most typical example of stiffness reinforcement measures. On the other hand, it is not easy to find the optimal stiffness reinforcement position for three-dimensional springback in complex parts. As a new attempt, a method of combining natural vibration analysis and optimization has been proposed (see Non-Patent Document 1).

[0010] That is, focusing on the fact that the natural frequency is proportional to the square root of the stiffness and inversely proportional to the square root of the density (mass), the elastic deformation mode of springback is identified, the natural vibration mode corresponding to that elastic deformation mode of springback is selected, some of the elements are replaced with highly elastic material of the same density so that the natural frequency of that natural vibration mode increases, and the optimal arrangement of the elements is found using an optimization tool, etc. This makes it easy to find the optimal position for stiffness reinforcement.

[0011] However, this method has the problem that the natural vibration mode must be selected manually, which is time-consuming. In addition, even if the natural vibration mode is selected automatically, the selection criteria are not clear, so it is not always possible to select a natural vibration mode that corresponds to the elastic deformation mode of springback, and the optimal arrangement of the high-elasticity material is not always obtained. Therefore, it is possible to select all natural vibration modes and find the optimal arrangement of the high-elasticity material for each of them, but this has the problem of being too costly. For this reason, it is not easy to perform an analysis to reduce the deformation of the member caused by springback. [Prior art documents] [Non-patent literature]

[0012] [Non-Patent Document 1] Shunji Hiwatari and 1 other, "Comprehensive Approach to Forming Issues of High Strength Steel Plates," Special Lecture at the Plate Forming Forum of the Forming Engineering Division of the Iron and Steel Institute of Japan, The Iron and Steel Institute of Japan, January 14, 2005 Summary of the Invention [Problem to be solved by the invention]

[0013] The present invention has been made to solve such conventional problems, and has an object to easily select a natural vibration mode corresponding to the strain energy, stress vector, or strain vector of a component without performing a springback analysis, and to easily perform an analysis for reducing deformation of the component that is thought to be caused by springback. [Means for solving the problem]

[0014] The analysis device of the present invention has a press molding analysis unit that performs press molding analysis on the part based on finite element model data that indicates the shape of the part and material property data that indicates the material properties of the part, and generates first distribution data that indicates a distribution of at least one parameter of the part's strain energy, stress vector, and strain vector; a natural vibration analysis unit that generates second distribution data for each natural vibration mode based on the finite element model data and the material property data, the second distribution data indicating the distribution of the parameters of the part in each natural vibration mode; a mode decomposition unit that determines the degree of agreement between the first distribution data and each of the second distribution data in each natural vibration mode; and a mode selection unit that selects one or more natural vibration modes based on the degree of agreement.

[0015] In the analysis device of the present invention, two or three of the strain energy, stress vector, and strain vector of the member are used as the parameters.

[0016] In the analysis device of the present invention, the mode selection unit evaluates the parameters at a plurality of integration points in the plate thickness direction of the component, and selects one of the natural vibration modes based on the degree of agreement.

[0017] The analysis method of the present invention includes: The computer system a press molding analysis process for performing a press molding analysis on the member based on finite element model data indicating a shape of the member and material property data indicating a material property of the member, and generating first distribution data indicating a distribution of at least one parameter of a strain energy, a stress vector, and a strain vector of the member; The computer systema natural vibration analysis process for generating, for each natural vibration mode, second distribution data indicating a distribution of the parameters of the component in the each natural vibration mode based on the finite element model data and the material property data; The computer system a mode decomposition process for determining a degree of agreement between the first distribution data and each of the second distribution data in each of the natural vibration modes; The computer system At least a mode selection step is performed in which one or more natural vibration modes are selected based on the degree of coincidence.

[0018] In the analysis method of the present invention, two or three of the strain energy, stress vector, and strain vector of the member are used as the parameters.

[0019] In the analysis method of the present invention, the mode selection step evaluates the parameters at a plurality of integration points in the plate thickness direction of the component, and selects one of the natural vibration modes based on the degree of agreement.

[0020] The computer program of the present invention causes a computer to execute the following steps: a press molding analysis process for performing a press molding analysis of the member based on finite element model data indicating a shape of the member and material property data indicating the material properties of the member, and generating first distribution data indicating a distribution of at least one parameter of the member's strain energy, stress vector, and strain vector; a natural vibration analysis process for generating second distribution data for each natural vibration mode based on the finite element model data and the material property data, indicating the distribution of the parameters of the member in each natural vibration mode; a mode decomposition process for determining the degree of agreement between the first distribution data and each of the second distribution data in each natural vibration mode; and a mode selection process for selecting one or more natural vibration modes based on the degree of agreement.

[0021] In the computer program of the present invention, two or three of the strain energy, stress vector, and strain vector of the member are used as the parameters.

[0022] In the computer program of the present invention, the mode selection step evaluates the parameters at a plurality of integration points in the plate thickness direction of the component, and selects one of the natural vibration modes based on the degree of agreement. Effect of the Invention

[0023] According to the present invention, it is possible to easily select a natural vibration mode corresponding to the strain energy, stress vector, or strain vector of a member without performing a springback analysis. Therefore, it is possible to easily perform an analysis for reducing deformation of the member that is thought to be caused by springback. [Brief description of the drawings]

[0024] [Figure 1] 4 is a flowchart illustrating an example of an operation of the analysis device according to the present embodiment. [Diagram 2] 1A and 1B are schematic diagrams showing an example of a member before and after division into elements. [Diagram 3] FIG. 13 is a schematic diagram illustrating a case where a vector is used as a parameter of the degree of match. [Figure 4] FIG. 13 is a characteristic diagram showing the relationship between the order of a natural vibration mode and the degree of agreement between distribution data. [Diagram 5] FIG. 2 is a block diagram showing an example of a functional configuration of an analysis device according to the present embodiment. [Figure 6] FIG. 2 is a schematic diagram showing the internal configuration of a personal user terminal device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] Various embodiments of the present invention will be described below with reference to the drawings. However, it should be noted that the technical scope of the present invention is not limited to these embodiments, but extends to the inventions described in the claims and their equivalents.

[0026] Fig. 1 is a flowchart for explaining an example of the operation of the analysis device 1. The processing flow shown in Fig. 1 is executed mainly by the processing unit 13 of the analysis device 1 in cooperation with each element of the analysis device 1, based on a program previously stored in the storage unit 12 of the analysis device 1 shown in Fig. 5. The configuration of the analysis device 1 will be described later.

[0027] First, the processing unit 13 generates finite element model data by dividing the shape of a component into a plurality of elements of specific shapes and sizes based on the "CAD model data and generation condition data" stored in the storage unit 12 (step S101). The processing unit 13 also stores the generated finite element model data in the storage unit 12. Note that HyperMesh, a commercially available application program, is used for the generation process of the finite element model. However, it is also possible to use other application programs (e.g., ANSA).

[0028] Fig. 2(a) is a schematic diagram (perspective view) showing an example of a member before being divided into elements. Fig. 2(b) is a schematic diagram (perspective view) showing an example of a member after being divided into elements. When the member 201 shown in Fig. 2(a) is divided into a plurality of rectangular elements by the processing unit 13, it becomes a member 211 shown in Fig. 2(b).

[0029] Next, the processing unit 13 performs press forming analysis by the finite element method based on the finite element model data and material property data stored in the storage unit 12, and generates first distribution data indicating the distribution of any one of the parameters of the strain energy, stress vector, and strain vector of the member (step S102). The stress-strain state of the member (at the bottom dead center) for which springback analysis has not yet been performed is considered to be equivalent to the driving force of springback. In consideration of this, in this embodiment, the stress-strain state of the member at the bottom dead center is used as an index of the driving force of springback without performing springback analysis. The processing unit 13 stores the generated first distribution data in the storage unit 12. Note that, for the analysis processing of press forming, HyperForm, which is a commercially available application program, is used. However, it is also possible to use other application programs (LS-DYNA, PAM-STAMP, etc.).

[0030] Next, the processing unit 13 generates second distribution data indicating the distribution of the above parameters of the component in each natural vibration mode for each natural vibration mode based on the finite element model data, material property data, and boundary condition data stored in the storage unit 12 (step S103). The processing unit 13 also stores each of the generated second distribution data in the storage unit 12. Note that OptiStruct, which is a commercially available application program, is used for the analysis processing of the natural vibration. However, it is also possible to use other application programs (such as Nastran).

[0031] Next, the processing unit 13 obtains the degree of agreement between the distribution data for each combination of the first distribution data stored in the storage unit 12 and the second distribution data in each natural vibration mode (step S104). That is, the processing unit 13 obtains the degree of agreement between the distribution data by determining the degree of correlation between the parameters in each natural vibration mode and the parameter values ​​after press forming for each element of the component.

[0032] In this embodiment, one of the strain energy, stress vector, and strain vector of the member is used as the parameter. Below, a method for determining the degree of agreement between distribution data will be described for the cases where the parameter is a scalar (strain energy) and the vector (stress vector or strain vector).

[0033] [When the parameter is a scalar (strain energy)] Specifically, the processing unit 13 calculates the degree of agreement between the distribution data by solving the simultaneous linear equations shown in the following formula (1). Here, u ij denotes the strain energy value of element j in the i-th natural vibration mode, and u Pj denotes the strain energy value of element j at the bottom dead center, and a i indicates the degree of agreement between the i-th natural vibration mode and the strain energy value. i A larger magnitude indicates a higher degree of agreement between the distribution data.

[0034]

number

[0035] Alternatively, the processing unit 13 can obtain the degree of agreement between the distribution data by calculating the difference between the parameter value in each natural vibration mode and the parameter value at the bottom dead center. Specifically, the processing unit 13 can obtain the degree of agreement between the distribution data by calculating the following formula (2) or (3). Here, u ij denotes the strain energy value of element j in the i-th natural vibration mode, and u Pj denotes the strain energy value of element j at the bottom dead center. i ,c i indicates the degree of agreement between the i-th natural vibration mode and the strain energy value. i ,c i A larger magnitude indicates a higher degree of agreement between the distribution data.

[0036]

number

[0037] The processing unit 13 stores the obtained degrees of agreement between the distribution data in the storage unit 12. In this embodiment, the degree of agreement a between the i-th natural vibration mode and the strain energy value is i ,b i ,c i Of these, a i The following will explain the case where the above is used as an example.

[0038] [When the parameter is a vector (stress vector or strain vector)] (1) First Method Specifically, the processing unit 13 calculates the degree of agreement between the distribution data by the following formula (4): Mij is the maximum principal stress vector or maximum principal strain vector of element j in the i-th natural vibration mode in the modal analysis. Pj is the maximum principal stress vector or maximum principal strain vector (bottom dead center) of element j in press forming analysis. Mij is the minimum principal stress vector or minimum principal strain vector of element j in the i-th natural vibration mode in the modal analysis. Pj is the minimum principal stress vector or minimum principal strain vector of element j (bottom dead center) in press forming analysis. d i indicates the degree of agreement between the i-th natural vibration mode and the springback deformation. d i The larger the magnitude of , the higher the degree of agreement between the distribution data. In equation (4), the stress is reversed between the modal analysis and the press forming analysis, so a negative sign (-) is added.

[0039]

number

[0040] (2) Second Method Specifically, the processing unit 13 calculates the degree of agreement between the distribution data by the following formula (5): Mij is the maximum principal stress vector or maximum principal strain vector of element j in the i-th natural vibration mode in the modal analysis.Pj is the maximum principal stress vector or maximum principal strain vector (bottom dead center) of element j in press forming analysis. Mij is the minimum principal stress vector or minimum principal strain vector of element j in the i-th natural vibration mode in the modal analysis. Pj is the minimum principal stress vector or minimum principal strain vector of element j (bottom dead center) in press forming analysis. d i indicates the degree of agreement between the i-th natural vibration mode and the minimum principal stress vector or the minimum principal strain vector. d i The larger the magnitude of , the higher the degree of agreement between the distribution data. In equation (5), the stress is reversed between the modal analysis and the press forming analysis, so a negative sign (-) is added.

[0041]

number

[0042] A case where a vector is used as a parameter of the degree of agreement in formula (4) of the first method and formula (5) of the second method will be described with reference to FIG. 3. Here, a stress vector is exemplified as the parameter. In this embodiment, the degree of agreement between the natural vibration mode and the springback deformation, which includes both the "angle deviation" and the "vector magnitude", is expressed for the stress vector of the press forming analysis and the stress vector of the mode analysis. For this reason, the inner product is used.

[0043] Next, the processing unit 13 selects one or more (a small number), here one, natural vibration mode based on each of the degrees of agreement between the distribution data stored in the storage unit 12 (step S105). Unlike the present embodiment, when the degree of agreement between the distribution data is evaluated using the shape (displacement) of the member, only one relationship (characteristic diagram) can be created for the relationship between the degree of agreement between the natural vibration mode and the distribution data. In contrast, in the present embodiment, the degree of agreement between the distribution data is evaluated using parameters of the strain energy, stress vector, or strain vector of the member. In this case, parameters can be evaluated at each integral point in the plate thickness direction of the member, and characteristic diagrams can be created for the relationship between the degree of agreement between the natural vibration mode and the distribution data for the number of integral points. As a result, in the present embodiment, as described later, the processing unit 13 can select, for example, only the 8th mode as the natural vibration mode corresponding to the deformation of the member that is thought to be caused by springback based on the degree of agreement between the distribution data.

[0044] Next, the processing unit 13 places beads in the finite element model data stored in the memory unit 12 based on the material property data, boundary condition data, and placement condition data stored in the memory unit 12 so as to increase the natural frequency of the generated natural vibration mode (step S106).

[0045] Here, arranging a bead in the finite element model data means providing irregularities on the surface of a member belonging to an element included in the finite element model data. In this way, the bead in the present invention means providing irregularities on the surface of a member, and is a concept that also includes embossing and the like.

[0046] Then, the processing unit 13 stores the finite element model data after the bead is placed in the storage unit 12. The bead placement process uses OptiStruct, a commercially available application program. In addition, when placing the bead, the ratio of the bead placement area to the component area can be specified. Here, the component area is the area of ​​the surface of the component on which the bead can be placed. The bead placement area is the area of ​​the surface of the component on which the bead is placed. If this ratio is made too large, the beads will be placed in most of the area of ​​the component. However, there are cases where restrictions are imposed on the area in which the beads are placed depending on the shape of the component, the attachment point of the component, and the relationship with other components. In addition, there are cases where it is desired to make it easier to design the component by setting only the area in which the bead is placed that contributes greatly to suppressing the deformation of the component that is thought to be caused by springback as the area in which the bead is placed. From this perspective, the user operates the operation unit 14 to appropriately specify the ratio of the bead placement area to the component area.

[0047] Next, the processing unit 13 updates the first distribution data of the member by determining, by the finite element method, any one of the parameter values ​​of the strain energy, stress vector, and strain vector generated in each element of the member based on the "finite element model data, material property data, and press molding condition data after the bead is placed" stored in the storage unit 12 (step S107). The processing unit 13 also stores the "first distribution data after the bead is placed" thus generated in the storage unit 12. Note that HyperForm, which is a commercially available application program, is used for the analysis processing of the press molding. However, it is also possible to use other application programs (LS-DYNA, PAM-STAMP, etc.).

[0048] Next, the processing unit 13 judges whether the difference between the parameter value of the component determined based on the first distribution data after the bead is placed and the target parameter value of the component is within a predetermined range (step S108). This judgment can be realized, for example, by judging whether all the differences between the parameter value of each element of the component on which the bead is placed and the target parameter value of each element are within a predetermined range.

[0049] If the result of this determination is that the difference between the parameter value of the member determined based on the first distribution data after the bead is placed and the target parameter value of the member is not within the predetermined range, the process returns to step S103. Then, the process of steps S104 to S108 is repeated using "each (latest) finite element model data after the bead is placed" stored in the storage unit 12 until the difference between the parameter value of the member determined based on the first distribution data after the bead is placed and the target parameter value of the member falls within the predetermined range. Then, when the difference between the parameter value of the member determined based on the first distribution data after the bead is placed and the target parameter value of the member falls within the predetermined range, the processing unit 13 causes the display unit 15 to display information specifying the bead placement (the latest bead placement obtained in step S106) in which the difference between the parameter value of the member considered to be after springback and the target parameter value falls within the predetermined range. Then, the process according to the flowchart of FIG. 1 is terminated. The information specifying the bead placement can include, for example, information such as the position, shape, and height (depth) of the bead in addition to the image. In addition, information indicating the natural vibration mode selected when the parameter values ​​of the component considered to be after springback and the target parameter values ​​fall within a predetermined range (the latest natural vibration mode obtained in step S105) may be displayed on the display unit 15.

[0050] In the process of step S109, for example, information specifying the arrangement of the beads is displayed. However, the shape of the bead is complex. Therefore, it is not easy to arrange the beads on the component according to the information. Therefore, the user determines the actual arrangement of the beads with respect to the component (i.e., the shape of the component) based on the arrangement of the beads in the information, the shape and attachment position of the component, the relationship with other components, etc.

[0051] In this way, the processing unit 13 of the analysis device 1 performs press forming analysis, natural vibration analysis, etc. on the finite element model data. The processing unit 13 also selects one natural vibration mode based on the degree of agreement of the parameter values, and arranges beads in the finite element model data so that the natural frequency of this natural vibration mode increases. Then, the processing unit 13 performs press forming analysis again on the finite element model data after the beads have been arranged. Then, the arrangement of beads and the press forming analysis are repeated until the difference between the parameter values ​​of the component after the press forming analysis and the target parameter values ​​falls within a predetermined range. This allows the user to easily select the natural vibration mode corresponding to the springback deformation.

[0052] In the flowchart of FIG. 1, the processes of steps S107 and S108 may be omitted.

[0053] Next, an example of this embodiment will be described. In this example, a hat-shaped member having the shape shown in FIG. 2 was analyzed. The dimensions of the member were a length of 300 mm, a cross section of 58×36 to 46×26 mm, and a flange width of 26 mm. The plate thickness of the member was 1.2 mm. The material constituting the member was a steel plate. The physical properties of the steel plate were a Young's modulus of 206 GPa, a Poisson's ratio of 0.3, and a specific gravity of 7.8. The friction coefficient of the steel plate was 0.12.

[0054] Press forming analysis, natural vibration analysis, and mode decomposition were performed under the above conditions, and the relationship between the order of the natural vibration mode and the degree of agreement between the distribution data was obtained, as shown in Figure 4. Here, the horizontal axis indicates the order of the natural vibration mode, and the vertical axis indicates the degree of agreement between the distribution data (between the first distribution data based on springback deformation and the second distribution data for each natural vibration mode). In Figure 4, in order to bring the value of the degree of agreement on the vertical axis closer to 1, the degree of agreement is expressed as YP, where YP is the yield point. n It is divided by n, where n is the number of elements.

[0055] In this embodiment, the degree of agreement between the distribution data is evaluated using the parameters of the strain energy, stress vector, or strain vector of the member, so that the parameters are evaluated at multiple integration points in the plate thickness direction of the member. In FIG. 4, the multiple integration points are evaluated at two points, the plate thickness center and the plate thickness upper surface layer of the member, and two types of characteristic diagrams obtained corresponding to each integration point are shown. The stress at the plate thickness center is a factor of torsional deformation, and the stress at the plate thickness upper surface layer is a factor of bending deformation, and it can be said that the mode of the order that shows a high degree of agreement in both is excellent in accuracy. From the two types of characteristic diagrams, only the 8th mode has a high degree of agreement for both integration points. The 1st, 2nd, 12th modes, etc., in which only one integration point is high, are excluded. In this embodiment, only the 8th mode can be selected as the natural vibration mode corresponding to the deformation of the member caused by springback, and it is possible to reliably reduce the deformation of the member caused by springback.

[0056] Finally, a hardware configuration of the analysis device 1 in this embodiment will be described below.

[0057] The analysis device 1 executes programs that have already been installed, and executes various processes by referring to data stored in the storage unit 12 and / or data stored in other devices. The analysis device 1 also executes various processes according to instructions input by a user via the operation unit 14, and presents the results to the user via the display unit 15. To this end, the analysis device 1 has a communication unit 11, a storage unit 12, a processing unit 13, an operation unit 14, and a display unit 15.

[0058] The communication unit 11 has a communication interface circuit for connecting the analysis device 1 to a network (not shown). The communication unit 11 passes data received from other devices (not shown) via the network to the processing unit 13. The communication unit 11 also transmits data received from the processing unit 13 to other devices via the network.

[0059] The storage unit 12 has, for example, at least one of a semiconductor memory, a magnetic disk device, and an optical disk device. The storage unit 12 stores application programs, data, etc. used for processing in the processing unit 13. The storage unit 12 stores, for example, a finite element model generation program, a press molding analysis program, a natural vibration analysis program, a mode decomposition program, a mode selection program, a bead placement program, etc. as application programs.

[0060] The storage unit 12 also stores the following data as preset initial setting data: As the first initial setting data, the storage unit 12 stores CAD (Computer Aided Design) model data indicating the position, size, and shape of the member. As the second initial setting data, the storage unit 12 stores material property data indicating the material properties of the member (dimensions, plate thickness, material, Young's modulus, Poisson's ratio, mass density, relationship between stress and strain, etc.). As the third initial setting data, the storage unit 12 stores generation condition data indicating the generation conditions of the finite element model (shape, size, etc. of elements). As the fourth initial setting data, the storage unit 12 stores press molding condition data indicating the press molding conditions (friction coefficient, member flange pressing force, etc.). As the fifth initial setting data, the storage unit 12 stores boundary condition data indicating boundary conditions (fixed points on the member, etc.). As the sixth initial setting data, the storage unit 12 stores arrangement condition data indicating the arrangement conditions of the bead (height, arrangement area, etc.).

[0061] Furthermore, the storage unit 12 stores the following data as intermediate data generated by the processing unit 13: That is, as the first intermediate data, the storage unit 12 stores finite element model data (position, shape, size, etc. of each element) corresponding to the CAD model data. As the second intermediate data, the storage unit 12 stores first distribution data indicating the distribution of parameter (strain energy, stress vector, or strain vector) values ​​of the member in the press forming analysis. As the third intermediate data, the storage unit 12 stores second distribution data indicating the distribution of parameter values ​​of the member in each natural vibration mode. As the fourth intermediate data, the storage unit 12 stores the degree of agreement between the distribution data. As the fifth intermediate data, the storage unit 12 stores the selected order of the natural vibration mode. As the sixth intermediate data, the storage unit 12 stores finite element model data after the bead is arranged. As the seventh intermediate data, the storage unit 12 stores distribution data indicating the distribution of parameter values ​​after the bead is arranged. Furthermore, the storage unit 12 may temporarily store temporary data related to a predetermined process.

[0062] The processing unit 13 has one or more processors and their peripheral circuits. The processing unit 13 is a processing unit, such as a CPU (Central Processing Unit), that comprehensively controls the overall operation of the analysis device 1. That is, the processing unit 13 controls the operation of the communication unit 11, the display unit 15, etc. so that various processes of the analysis device 1 are executed in an appropriate order based on the operation of the operation unit 14, the programs stored in the storage unit 12, etc. The processing unit 13 executes processes based on the programs (operating system programs, application programs, etc.) stored in the storage unit 12. The processing unit 13 can also execute multiple programs (application programs, etc.) in parallel.

[0063] The processing unit 13 includes a finite element model generating unit 131 that executes the process of step S101 in Fig. 1, a press molding analysis unit 132 that executes the processes of steps S102 and S107, a natural vibration analysis unit 133 that executes the process of step S103, a mode decomposition unit 134 that executes the process of step S104, a mode selection unit 135 that executes the process of step S105, a bead arrangement unit 136 that executes the process of step S106, a parameter determination unit 137 that executes the process of step S108, and a data drawing unit 138 that executes the process of step S109. Each of these units included in the processing unit 13 is a functional module implemented by a program executed on a processor included in the processing unit 13. Alternatively, each of these units included in the processing unit 13 may be implemented in the analysis device 1 as firmware.

[0064] The data drawing unit 138 executes a data drawing process. That is, the data provided from the finite element model generating unit 131, the press forming analysis unit 132, the natural vibration analysis unit 133, the mode decomposition unit 134, the mode selection unit 135, and the bead placement unit 136 is analyzed, the data is rendered in a predetermined format (for example, a contour diagram), and the drawing data is generated. Then, the data drawing unit 138 outputs the generated drawing data to the display unit 15 or the like. In this case, the display unit 15 functions as an output unit. However, this is not necessarily required. For example, when the communication unit 11 transmits data provided from the finite element model generating unit 131, the press forming analysis unit 132, the natural vibration analysis unit 133, the mode decomposition unit 134, the mode selection unit 135, and the bead placement unit 136 to an external device, the communication unit 11 functions as an output unit.

[0065] The operation unit 14 may be any device capable of operating the analysis device 1, such as a keyboard or a touch panel. A user can input instructions such as selection using this device. When operated by a user, the operation unit 14 generates a signal corresponding to the operation. The generated signal is then input to the processing unit 13 as an instruction from the user.

[0066] The display unit 15 may be any device capable of displaying a video, an image, etc., such as a liquid crystal display, an organic EL (Electro-Luminescence) display, etc. The display unit 15 displays a video, an image, etc. according to the drawing data supplied from the processing unit 13.

[0067] As described above, in this embodiment, it is possible to easily select a natural vibration mode corresponding to the strain energy, stress vector, or strain vector of a component without performing a springback analysis, and to easily perform an analysis to reduce the deformation of the component that is thought to be caused by springback.

[0068] In this embodiment, the case where any one of the strain energy, stress vector, and strain vector is used as a parameter of the member in the press forming analysis is exemplified, but any two or all three of these may be used. By using multiple parameters, it is possible to more accurately select the natural vibration mode corresponding to these difference values, and to reliably reduce the deformation of the member that is thought to be caused by springback. In addition, the shape of the member (selecting the natural vibration deformation mode corresponding to the shape after springback) may be added to these three parameters.

[0069] The present invention is not limited to this embodiment. For example, in this embodiment, the analysis device 1 has each unit shown in FIG. 5, but some of them may be included in a server device (not shown). The server device may have, for example, a storage unit corresponding to the storage unit 12 of the analysis device 1, and provide the analysis device 1 with the program, data, etc. stored in the storage unit, and cause the analysis device 1 to execute the analysis process. In this case, the processing unit 13 of the analysis device 1 acquires the program, data, etc. from the server device via the communication unit 11. On the other hand, when the program, data, etc. are stored in the storage unit 12 of the analysis device 1, the processing unit 13 acquires the program, data, etc. from the storage unit 12.

[0070] In addition, the server device may have a memory unit and a processing unit equivalent to the memory unit 12 and processing unit 13 of the analysis device 1, and perform analysis processing using programs, data, etc. stored in the memory unit, and provide only the results to the analysis device 1.

[0071] That is, the above-described embodiment can be realized by a computer executing a program. The functions of the components of the analysis device according to the embodiment (each unit 131-138 of the processing unit 13 in FIG. 5, etc.) can be realized by the operation of a program stored in the RAM, ROM, etc. of the computer. Similarly, each step of the analysis method according to the embodiment (steps S101-S109 of FIG. 1, etc.) can be realized by the operation of a program stored in the RAM, ROM, etc. of the computer. The functions may be realized by loading into memory and executing a program for realizing the functions of each component of the analysis device according to the embodiment (each unit 131-138 of the processing unit 13 in FIG. 5, etc.) and a program for each step of the analysis method according to the embodiment (steps S101-S109 of FIG. 1, etc.).

[0072] The memory unit 12 of the analysis device 1 shown in FIG. 5 may be composed of a hard disk device, a magneto-optical disk device, a non-volatile memory such as a flash memory, a read-only storage medium such as a CD-ROM, a volatile memory such as a RAM, or a combination of these.

[0073] In addition, a program for implementing the functions of each component of the analysis device according to this embodiment (such as each unit 131-138 of the processing unit 13 in FIG. 5) may be recorded on a computer-readable recording medium, and the program recorded on the recording medium may be read into a computer system and executed to execute the processing of each component. Note that the term "computer system" here includes hardware such as an OS and peripheral devices.

[0074] Furthermore, if a WWW system is used, the "computer system" may also include the homepage providing environment (or display environment). In addition, the term "computer-readable recording medium" refers to portable media such as flexible disks, optical magnetic disks, ROMs, and CD-ROMs, and storage devices such as hard disks built into computer systems. Furthermore, the term "computer-readable recording medium" may also include devices that dynamically hold a program for a short period of time, such as a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line, and devices that hold a program for a certain period of time, such as a volatile memory inside a computer system that serves as a server or client in such cases. Furthermore, the above-mentioned program may be one that realizes part of the above-mentioned functions, or may be one that can realize the above-mentioned functions in combination with a program already recorded in the computer system.

[0075] As a specific example, the analysis device shown in this embodiment has a computer function 100 as shown in FIG. 6, and the operations in this embodiment are carried out by a CPU 101 thereof. 6, the computer function 100 includes a CPU 101, a ROM 102, and a RAM 103. It also includes a controller (CONSC) 105 for an operation unit (CONS) 109, and a display controller (DISPC) 106 for a display (DISP) 110 serving as a display unit such as a CRT or LCD. It also includes a controller (DCONT) 107 for a hard disk (HD) 111 and a storage device (STD) 112 such as a flexible disk, and a network interface card (NIC) 108. These functional units 101, 102, 103, 105, 106, 107, and 108 are connected to each other via a system bus 104 so as to be able to communicate with each other.

[0076] The CPU 101 executes software stored in the ROM 102 or the HD 111, or software supplied from the STD 112, thereby generally controlling each component connected to the system bus 104. That is, the CPU 101 performs control to realize the operation in this embodiment by reading out a processing program (analysis program) for performing the above-mentioned operation from the ROM 102, the HD 111, or the STD 112 and executing it. The RAM 103 functions as the main memory, work area, etc. of the CPU 101.

[0077] CONSC 105 controls instruction input from CONS 109. DISPC 105 controls the display of DISP 110. DCONT 107 controls access to HD 111 and STD 112 which store the boot program, various applications, user files, network management program, and the above-mentioned processing programs in this embodiment. NIC 108 exchanges data bidirectionally with other devices on network 113. Instead of using a personal user terminal device, a specific computer or the like specialized for the analysis device of this embodiment may be used. [Industrial Applicability]

[0078] The present invention can be used, for example, in molding components that are applied to automobile bodies and the like. [Explanation of symbols]

[0079] 11 Communications Department 12 Storage section 13 Processing section 14 Control section 15 Display section

Claims

1. a press molding analysis unit that performs a press molding analysis on the member based on finite element model data that indicates a shape of the member and material property data that indicates a material property of the member, and generates first distribution data that indicates a distribution of at least one parameter of a strain energy, a stress vector, and a strain vector of the member; a natural vibration analysis unit that generates, for each natural vibration mode, second distribution data that indicates a distribution of the parameters of the component in the each natural vibration mode based on the finite element model data and the material property data; a mode decomposition unit that determines a degree of agreement between the first distribution data and each of the second distribution data in each of the natural vibration modes; a mode selection unit that selects one or more natural vibration modes based on the degree of coincidence; An analysis device comprising:

2. 2. The analysis device according to claim 1, wherein two or three of a strain energy, a stress vector, and a strain vector of the member are used as the parameters.

3. 3. The analysis device according to claim 1, wherein the mode selection unit evaluates the parameters at a plurality of integration points in the plate thickness direction of the component, and selects one of the natural vibration modes based on the degree of agreement.

4. A press molding analysis process in which a computer system performs a press molding analysis on the member based on finite element model data indicating the shape of the member and material property data indicating the material properties of the member, and generates first distribution data indicating a distribution of at least one parameter of the strain energy, stress vector, and strain vector of the member; a natural vibration analysis process in which a computer system generates, for each natural vibration mode, second distribution data indicating a distribution of the parameters of the component in the each natural vibration mode based on the finite element model data and the material property data; a mode decomposition process in which the computer system determines a degree of agreement between the first distribution data and each of the second distribution data in each of the natural vibration modes; a mode selection step of the computer system selecting one or more natural vibration modes based on the degree of agreement; An analysis method comprising at least the steps of:

5. 5. The analysis method according to claim 4, wherein two or three of a strain energy, a stress vector, and a strain vector of the member are used as the parameters.

6. 6. The analysis method according to claim 4, wherein the mode selection step evaluates the parameters at a plurality of integration points in the thickness direction of the component, and selects one of the natural vibration modes based on the degree of agreement.

7. a press molding analysis process for performing a press molding analysis on the member based on finite element model data indicating a shape of the member and material property data indicating a material property of the member, and generating first distribution data indicating a distribution of at least one parameter of a strain energy, a stress vector, and a strain vector of the member; a natural vibration analysis process for generating, for each natural vibration mode, second distribution data indicating a distribution of the parameters of the component in the each natural vibration mode based on the finite element model data and the material property data; a mode decomposition process for determining a degree of agreement between the first distribution data and each of the second distribution data in each of the natural vibration modes; a mode selection step of selecting one or more natural vibration modes based on the degree of agreement; A computer program characterized by causing a computer to execute the above.

8. 8. The computer program according to claim 7, wherein two or three of a strain energy, a stress vector, and a strain vector of the member are used as the parameters.

9. 9. The computer program according to claim 7 or 8, wherein the mode selection step evaluates the parameters at a plurality of integration points in the thickness direction of the component, and selects one of the natural vibration modes based on the degree of agreement.

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